Project Introduction and Overview
P-06025 Standing Table
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Matthew Bell
Craig Hudson
Jeffery Matusik
Kahamala Morgan
Maria Spagnola
Aditya Srinvas
Table of Contents
1 Project Introduction and Overview 5
1.1 Project Initiation 5
1.2 Project Beneficiary, the ARC 5
1.3 Definition of a Standing Table 6
1.4 Health Benefits of Standing 6
1.5 Project Projections 7
2 Team Mission Statements 9
2.1 Primary Goals 9
2.2 Primary Stakeholders 9
2.3 Key Business Goals 10
2.4 Primary and Secondary Markets 10
2.5 Success Winners and Qualifiers 11
3 Individual Roles and Responsibilities 13
3.1: Team Roles Tree 13
3.2 Project Manager, Craig A. Hudson 13
3.3 Report Organizer, Matthew Bell 13
3.4 Meeting Minutes, Jeff Matusik 14
3.5 Co-Lead Engineer, Maria Spagnola & Aditya Srinivas 14
3.6 Budget & Purchasing, Kahamala T. Morgan 14
4.1 Team Structure Tree 15
4.2 Power Team 16
4.3 Biomechanics & Ergonomics Team 16
4.4 Frame Design Team 17
5 Team Timeline 18
5.1 Winter Quarter 18
5.1.1 Needs Facet 18
5.1.2 Specifications Facet 18
5.1.3 Feasibility Assessment 19
5.1.4 Team Design 19
5.2 Spring Quarter, Future Plans 20
6 Ergonomics 21
6.1 Introduction to Ergonomics 21
6.2 Standing Risks and Benefits 22
6.3 Ergonomic Design Parameters 22
6.3.1 Height Thresholds 22
6.3.2 Weight Thresholds 24
6.3.3 Pad and Footplate Placement 24
6.3.4 Harness Design 25
6.3.5 Chest Pad and Table Parameters 25
7 Customer Needs and Specifications 27
7.1 Needs and Specifications Overview 27
7.2 Formal Needs Statements 27
8 Concept Development 32
8.1 General Concept Development 32
8.2 Detailed Concept Development 33
9 Project Feasibility 35
9.1 Feasibility overview 35
9.2 Non-weighted Pugh Analysis 35
9.3 Determination of Assessment Weights 36
9.4 Weighted Pugh Analysis 37
10 Base Design and Analysis 38
10.1 General Base Design 38
10.2 Fluid Drive System 39
11 Design of the Lifting Mechanism 41
11.1 Design Challenges 41
11.2 Solution Methods 42
12 Circuit Design and Analysis 44
12.1 Necessary Circuit Requirements 44
12.2 Circuit Components and Layout 44
13 Leg Design and Analysis 46
13.1 Free Body Diagram and Solutions 46
14 Table Top and Support Design and Analysis 48
14.1 Free Body Diagrams and Solutions 48
15 Product Strengths and Weaknesses 50
16 Method of Operation 52
16.1 Operating Instructions 52
16.2 Safeguards and Warnings 53
Appendices: Table of Contents 55
Appendix A – Project Proposal 57
Appendix A – Project Proposal 57
Appendix B – Mission Statement 60
Appendix C – Team Values and Norms 63
Appendix D – Gantt Chart 64
Appendix E – Feasibility 65
Section 1 – Pugh Analysis 65
Section 2 - QFD 66
Section 3 – Determination of Weights 68
Section 4 – Determination of Weights Results 69
Section 5 – Weighted Pugh Analysis 70
Appendix F – Ergonomics 71
Section 1 – Anthropometric Data Table (Height) 71
Section 2 – Relative Body Dimensions 71
Section 3 – Generic Body Weights 72
Section 4 – Segment Weights of 300lbs. Person 72
Section 5 – FEA Analysis of Footplate 73
Appendix G – The Five Whys 74
Appendix H – Concept Generation 78
Section 1 - Brainstorming 85
Section 2 – Requirements, Needs, and Guidelines 85
Section 3 – Design Parameters 86
Section 4 – Objective Trees 87
Section 5 – Morphological Charts 91
Section 6 – Individual Concepts 93
Section 7 – Team Preliminary Concepts 94
Section 8 – Final Morphological Chart 95
Section 9 – Final Concepts 96
Appendix I – Pneumatic Fluid Drives 97
Section 1 – Solid Model: “Extend” Drive Cylinder 97
Section 2 – Solid Model: Fluid Drive/Leg Interface 98
Section 3 – Fluid Drive Ratio Formulas 100
Section 4 – Force and Travel Ratios for Cylinder Bore 101
Section 5 – Fluid Drive Schematic 102
Section 6 – FEA Analysis of Drive Cylinder Assembly 103
Section 7 – Stress Lift Curves of Base Assembly 104
Appendix J – Force Determination for Lifting 105
Section 1 – Body Segment Weights 105
Section 2 – Strap Forces 105
Section 3 – Angle and Force Determination 106
Section 4 – Torque Equation 107
Section 5 – Force and Torque Summary 107
Section 6 – Forces and Torques Graph 108
Section 7 – Torques Generated by Individuals 109
Section 8 – Force Required to Lift Individuals 110
Section 9 – Actuator Duty Cycles 111
Section 10 – Free Body Diagram of Lift Arms 111
Section 11 – FEA Analysis of Lifting Arm 112
Section 12 – Pin Shear Calculations 113
Section 13 – Stress Life Curves for Lifting Assembly 114
Appendix K – Table Electronic Systems 115
Section 1 – Circuit Schematic 115
Section 2 – Battery & Charger 116
Section 3 – Wiring Diagram for Circuit 120
Appendix M – Force in Main & Secondary Support 125
Appendix N – Stress in Table & Bolt 128
Appendix O – Bill of Materials (BOM) 129
Appendix P – Assembly Plans 131
Appendix Q – Business Plan Outline: Standing Table 134
Appendix R – Engineering Drawings 147
1 Project Introduction and Overview
1.1 Project Initiation
Senior Design Project #P06205 was officially commissioned during the time that RIT received a grant from the National Science Foundation (NSF) and began to compile a list of projects that would meet the needs of the community, satisfy the objectives of Rochester Institute of Technology’s (RIT) Senior Design program, and qualify for funding via the NSF grant. The grant was provided to RIT for the purpose of furthering the design and development of devices to improve the quality of life of disabled individuals. Work on the project first began during the fall quarter of 2005 during which, Craig A. Hudson, the future project manager, began to compile preliminary documents detailing the needs, objectives, and design parameters that would need to be addressed by the team. The purpose of the project was to design, build, and test a standing table, also known as a powered standing lift, for use by the ARC of Monroe County in its residential program. A copy of the original project proposal, as presented to seniors entering the Senior Design program in the Fall of 2005 can be found in Appendix A.
1.2 Project Beneficiary, the ARC
The Arc of Monroe County is a non-profit (NP) foundation dedicated to providing services to individuals with physical or mental disabilities. The organization provides a warm enriching environment encouraging its members with physical or mental disabilities to celebrate their unique talents through recreation, community involvement and volunteerism. It provides a number a day, residential and vocational services which aim to meet the different variety of care types, length, and scope that are needed by different individuals. More information can be found at the foundation’s website located at .
The standing table project is an attempt to provide help to this noble cause in the form of Senior Design project (project #P06205) at RIT. As the ARC is an NP company, they do posses the necessary finances to purchase and use a commercially available standing table. The Standing Table Project is being designed by a team of six Rochester Institute of Technology students currently in their senior year.
1.3 Definition of a Standing Table
A standing table is a device that allows individuals, unable to stand on their own, maintain a vertical standing position with either partial or full weight support. A table also allows the users to transfer from a seated position in a wheelchair or bed to another seating location, or to a standing position with some aid. A more detailed analysis and description of the method of operation can be found in the discussion of the methods of operation found in section 16.
1.4 Health Benefits of Standing
Standing, in general, has a number of health benefits as it has been proven over the years by a number physicians and therapists. Standing facilitates the improvement of balance and strength of the upper body, as well as improving the range of motion of the spine, hips, knees, and ankles. Additionally, standing aids in good blood circulation throughout the body. Standing is also able to reduce pressure issues through changing positions, improves systemic functions (digestive, bladder, respiratory, etc.). Standing also prevents the loss of bone density, alleviates pain caused by inappropriate positions and standing by itself also develops tolerance and endurance in the body. Another extremely important advantage of standing is the psychological benefits it provides to a person, as being reduced to spending your entire life from a seated position can be damaging to an individual’s self esteem. The standing table would provide its users a sense of independence and thus increase their self esteem. It can enhance social development and also interaction with peers. Thus, the standing table project is of immense importance for the ARC, and is a privilege for the team to design it. A more detailed analysis and description of the health benefits can be found in the discussion of the ergonomic factors found in section 6.
1.5 Project Projections
As written above, a standing table provides a number of advantages that the ARC is currently unable to make use of. By designing a standing table that is able to support 95% of the entire population, the ARC will be able to utilize this device for the enjoyment, benefit, and health of its residents. While the table is currently planned to be left in a single residential home that provides service for only a handful of individuals, the design of the table is such that transporting it is a fairly easy process.
As stated previously, the project commenced at the beginning of the winter quarter of the 2005-2006 school year at RIT, and is currently scheduled to finish at the end of the spring quarter in May of 2006. The team involved in this project has been able to expand their knowledge on the biomechanics of people with different physical disabilities, and have been able to gain experience in applying various engineering and design concepts in a multidisciplinary design environment. It is the team’s sincere desire that this project is going to be of great use to the ARC once it is finished, and would help to improve the quality living of all its members. Additionally, the team hopes that its final prototype is of a caliber that displays the quality of their hard work over the past five years, and would be able to compete in the market place if it was to be commercially produced.
2 Team Mission Statements
After defining a project, it is important for any group to formally state their mission. The intent of the team, within the next few pages, is to provide a brief overview of the team’s goals, priorities, and the limitations inherent to the project. For a comprehensive layout of the group’s mission statement, please see Appendix B.
2.1 Primary Goals
The primary goal of the team, as defined by the customer, was to provide the ARC of Monroe County with a complete working prototype of a standing table. The table is to be used on a daily, or near daily basis, so it is imperative that they are presented with a functioning, low maintenance design.
2.2 Primary Stakeholders
The primary stakeholders for the standing table project are the team members, the ARC of Monroe county therapists and residents, and Dr. Elizabeth DeBartolo, the team mentor. The stakeholders with the most vested into the project are the team members, and their mentor. For reasons that should be apparent for the interests of the team, successful completion of the Senior Design curriculum is a factor involved in determining their ability to graduate at the end of the current school year, and hence places the team as a primary stakeholder. However, the reasons for the team mentor’s stake in the project may not be quite as obvious. Due to the fact that funding for the project was provided by a grant from the National Science Foundation, Dr. Debartolo has been charged with being a good steward of a large sum of grant money. In order to ensure future funding of projects, it is important that currently funded teams utilize the available funds to the best of the school’s ability. The ARC affiliates themselves have the most potential to gain from this project, as they will be able to acquire a fully working, customized standing table, at no cost to them.
2.3 Key Business Goals
Although Senior Design teams rarely evolve into anything more than a student led team, it is still important to conduct the team as though it is, or at the least has the potential, to be a business. Hence, the business goals of the team reflect a broad collection of ideals held by most of the business community. First and foremost, the design team is striving to build a better product, or minimally, a better valued product than currently exists on the commercial market. During the attempt to reach the first goal, there shouldn’t be any excessive, or undue, liability placed upon any of the stakeholders in any form. Please refer to Appendix B for a more in depth view of these liabilities, and how they are to be minimized.
2.4 Primary and Secondary Markets
Again following the premise that a Senior Design project has the potential to be a working business prototype, a set of detailed primary and secondary markets were laid out. Listed as the primary market targets were the ARC residents and therapists, the engineering faculty at RIT, parents of students on the design team, and the students who could have been potential team members.
As the ARC is the main material beneficiary of the project, it is important that they are satisfied with the features of the design, and the overall build quality. In order to develop a product it is a bare necessity to have students that are not only well qualified, but also interested in the project. Thus, the engineering students of RIT also become a market as it is imperative to attract a broad knowledge base along with top notch skills. If the project does not appeal to students as much as other projects do, there is a risk of acquiring students that are here to pass the course, and are not interested in performing at the levels required.
The engineering faculty at RIT, and the parents of students at RIT, make up a primary market in that they have a vested interest in the success of their students and children. As is true of any investment, individuals desire to see their work and money used to its greatest potential. Thus, parents have invested a large amount of time and money in raising, teaching, and supporting current students, while the engineering faculty has invested a large amount of time in teaching and training their students. Therefore, it is not much to ask that the final capstone project would be able to showcase, to its utmost, the extent to which students have grown and acquired knowledge of engineering practices.
2.5 Success Winners and Qualifiers
While the formal mission statement details the success qualifiers and winners, only a very brief overview will be given here. Essentially, the qualifiers are a list of the needs and goals that must be met in order for the team to reach minimal success. Success winners, on the other hand, are a list of what the team can do to meet and exceed any expectations placed upon the team and the design of the standing table. Again, as these qualifiers and winners are practically a formal written statement of customer needs, and a modified formation of team goals, they will not be discussed here further. Please refer to Appendix B, Sections 8 & 9 if more information is desired.
3 Individual Roles and Responsibilities
3.1: Team Roles Tree
Figure 1 Individual Jobs
3.2 Project Manager, Craig A. Hudson
At the start of the first group meeting, the roles and responsibilities of the group members were assigned. The group leader, Craig Hudson, a mechanical engineer, was responsible for keeping the group on target and meeting the deliverables schedule as established by our customer and the RIT Senior Design Program. Craig facilitated the communication between the many disciplines involved and also served as a point of reference for the entire group.
3.3 Report Organizer, Matthew Bell
Matthew Bell, a mechanical engineer, was designated as the main contact person for gathering together the pieces of the report. All individual work was to be given to him so that he could provide some cohesion between the different written portions that were to be combined for the final report.
3.4 Meeting Minutes, Jeff Matusik
Jeff Matusik, an industrial engineer, was responsible for recording any important information that was given or developed during the group meetings and distributed it to the team members via email. Jeff served as the reference point for our previous concepts and ideas throughout the project so that a linear timeline could easily be looked back upon.
3.5 Co-Lead Engineer, Maria Spagnola & Aditya Srinivas
Maria Spagnola, a mechanical engineer, and Aditya Srinivas, an electrical engineer volunteered to both become Co-Lead Engineers. They were both responsible for proofreading and validating any paper work that was put into the group binder and report. Maria and Aditya also served as secondary checks for any of the calculations that were performed.
3.6 Budget & Purchasing, Kahamala T. Morgan
Kahamala Morgan was responsible for the team budget. Kahamala was not only in charge of putting together the final Bill of Materials, but also kept the group members aware of team spending in order to prevent the project from becoming over budget.
4 Team Structure
Due to the fairly large size of the team, and the many disciplines involved, it was determined that it would be best to divide the team into three subgroups. Each subgroup would be responsible for one of the three major components of the standing table: Biomechanics/ergonomics, frame, and power/force generation. A copy of the “Team Values and Norms”, a written contractual agreement of teamwork, can be found in Appendix C.
4.1 Team Structure Tree
Figure 2 Team Organizational Chart
4.2 Power Team
Because of the somewhat wider scope of involved in powering the standing table, the Power subgroup was divided into an electrical and actuators/cylinders subset. Aditya was responsible for the battery selection, designing a remote that would be used to operate the device, and for interfacing the electrical components with the mechanical components. Craig was responsible for selection of the actuators that would be used to lift the patients using the standing table. This was a challenging, yet exciting, responsibility because the actuators needed to be able to produce enough force to safely lift an individual, while at the same time fitting the limited space design of a standing table. A second important issue was also the development of expanding legs for the base of the frame. The legs had to be designed such that they were expandable to accommodate different chair styles, but at the same time must still be able to fit into the compact footprint area of the design.
4.3 Biomechanics & Ergonomics Team
The Biomechanics/Ergonomics team was responsible for determining the relationship between the interaction of the human subject and the lifting mechanism, table surface, and pads/supports. Other responsibilities included determining the forces acting on the body, the range of comfort of the average adult, as well as the height and weight requirements necessary to ensure a safe and working design. The information provided by this team was invaluable in determining not only the position of the pads and supports which they designed, but also for generating the dimensions our overall design in order to provide a safe, stable, and comfortable environment for the user when using our product.
4.4 Frame Design Team
Finally, the responsibilities of the Frame team were to design and analyze the primary and secondary supports of the system, determine the load requirements and forces acting on the system, and also identify the possible areas of maximum stress and fatigue. The frame team was also responsible for designing a table top that was not only height adjustable, but able to pivot to a location that was comfortable for the user.
While each of the three subgroups had specific assigned responsibilities, it was a group effort to ensure that all the different components interfaced well with each other. Additionally, as needed, different teams would provide some concept development as well as technical support to other groups. The subgroups were, in no way, forced to adhere only to their assigned work, but were encouraged to network with, and work with, other groups on a weekly basis.
5 Team Timeline
5.1 Winter Quarter
A complete Gantt chart detailing the proposed project schedule for the team can be found in Appendix D.
5.1.1 Needs Facet
A majority of the preliminary information necessary for this project was completed prior to the start of Senior Design due to the project leader’s completion of Design Project Management during the fall quarter. However, a group review and revision of these documents was performed after meeting with the Arc Representative to determine their customer needs. The initial documents had been created only with the input from a single individual. By reviewing all of the preliminary documents as a team, the unique input, as well as combined team input, was added to ensure much broader coverage and analysis of the project. The next task was to complete a needs assessment analysis. Extensive research was performed to ascertain any standards that pertained to the construction of a standing table and to also compare current models in the market. Simultaneously, Functional and Why analyses were performed to determine which design functions and parameters would determine the success, or failure of a design, what environment the standing table would be used in, and the underlying reasons why the consumer needed this product. The needs assessment enabled the team to identify the customer’s needs and develop a plan of action that would satisfy those needs.
5.1.2 Specifications Facet
The next phase in the product development was the specifications facet. During this phase, a requirements document was finalized, a verification and validation plan was created, and the QFD was reviewed and revised. The general dimensions and other specifications of the standing table were determined in order to begin the concept process. During the concept development period, there was a group brainstorming session in which a morphological chart was created. From these ideas, the six group members developed two individual concept ideas to present to the group. Through a non-weighted Pugh analysis, the best of these twelve ideas were decided upon and presented at the concept peer review. After this review, more concept research and development was performed and finally, the group decided upon a final concept. The results of this Pugh analysis can be found in Appendix E, Section 1.
5.1.3 Feasibility Assessment
As this section is oriented towards giving a general overview of the project schedule and series of events, no in depth look will be given here. For more information, please refer to the Feasibility Analysis, Section 9.
5.1.4 Team Design
During the latter half of the quarter the following goals were accomplished: development of component models and drawings, identification of suppliers and vendors, creation of assembly and production drawings, and a final cost analysis and Bill of Materials. The final phase was to review the QFD and needs assessment to ensure that we had met and exceeded the customer’s requirements. The remainder of the quarter was spent preparing for the PDR and preparing for senior design II.
5.2 Spring Quarter, Future Plans
During the second ten weeks of the project, the group will continue to implement the ideas and concepts from Senior Design I into a working model. It is expected that most of the parts necessary will be delivered within the first or second week of spring quarter. The primary focus of the quarter will be to finalize a build plan and create a finished prototype. Machining tasks will be assigned and executed based on skill level. If time permits, the prototype will be thoroughly tested, and preparation for the final design review will be completed.
The group will also decide upon an instruction manual for the utilization of the standing table, in order to ensure that any sources of failure and misuse are minimized. The manual will contain information about inspecting for structural damage, but it will also provide information about replacing batteries and other high wear parts, if necessary. The manual will also be used as a safety manual; what to do in the case of the device getting stuck while in operation and explain the emergency override features.
Finally, the team will once again put together a detailed report based on our analysis from winter quarter and from our work and findings from spring quarter into a comprehensive report that will cover the conception of the design to its implementation as a working prototype.
6 Ergonomics
6.1 Introduction to Ergonomics
Before any real design work or even any useful brainstorming could begin, it was vitally important for the team to research and understand the basic ergonomic factors relating to a standing table. Ergonomics is the science of designing a job or task to fit a worker, rather than the worker trying to adapt to the job. Modifying tasks, tools, and work stations can help reduce physical stress on a person’s body and eliminate potential musculoskeletal disorders (MSD). Musculoskeletal disorders are injuries to the soft tissues of the body (muscles, ligaments, tendons, etc.) and the nervous system. When equipment is designed without considering ergonomic principles, there is an increased risk of exposure to physical stress, strain, awkward postures, forceful exertion, repetitive motion, and heavy lifting. Health care facilities have been identified by OSHA as an environment where ergonomic stressors exist.
There are many residents/patients at care facilities that are wholly dependent on staff members for daily activities. Each activity involves an interaction with handling or transferring the resident which could result in employee injuries. Injuries to workers can increase costs to the employer and cause staffing shortages. To minimize injuries, OSHA recommends that “employers identify and address ergonomic stressors in their facility’s safety and health plan”. Six of the top 10 professions at greatest risk for back injury are: nurse’s aides, licensed practical nurses, registered nurses, health aides, radiology technicians and physical therapists (Nash, 2003).
6.2 Standing Risks and Benefits
A patient or resident, who is dependent upon others, cannot be left sitting down for prolonged periods of time. Sitting is a static posture that increases stress in the neck, shoulders, back, arms, and legs. In particular, it can add large amounts of pressure to spinal disks and back muscles. In order to help alleviate these stressors, the resident should be allowed to stand up periodically. Standing helps increase blood flow and reduces fatigue.
A resident who is dependent upon others to transfer from a sitting to standing position would need the assistance of a staff member. The staff member, however, should not try to lift the patient themselves as it increases the risk of injury to themselves. Even if the injury is not acute, the repetition of such actions can lead to an MSD. Therefore, it is necessary to have a lifting device such as a standing table to help a staff member assist a resident or patient.
When lifting a person from a sitting position, it is important for the patient to feel secure and comfortable. An efficient and simple design will help make the device easy to use for the assisting staff member. Any part of the lifting device which the patient may come into contact with should be comfortable and safe.
6.3 Ergonomic Design Parameters
6.3.1 Height Thresholds
To design a lifting device, one must consider the variable sizes of a potential user. In order to help determine the relative size of the device, anthropometric data is used to estimate the measurements of the user. When considering a mixed population (50% male, 50% female), the 95th percentile male and 5th percentile female are used as upper and lower limits. Using these percentiles, 95% of all users will be covered (because of the overlap between male and female body dimensions).
Research done by Drillis and Contini has suggested that the body is made up of mechanical links which are proportional to our total body height. The link-length diagram in Figure 3 shows the length of body segments as proportions to body height. The height of a 95th percentile male is 73.6” and the stature of a 5th percentile female is 59.8” (see Appendix F, Section 1). Multiplying these heights by the ratios will give you the approximate length of the body segment (see Appendix F, Section 2).
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Figure 3
6.3.2 Weight Thresholds
The design parameters for this device require it to be able to lift a maximum of 300lbs. To determine the relative weights of body segments, ratios of the total body weight can be calculated based on data from Drillis and Contini (see Appendix F, Section 3). For example, the relative weight of a 300lbs person’s thigh would be calculated by first determining the weight of the total leg (300lbs. X .157 = 47.1lbs.) and then taking 63.7% of the total leg (30.0lbs.). For the rest of the relevant body segment weights see Appendix F, Section 4.
6.3.3 Pad and Footplate Placement
In order to lift someone from a seated position, a moment is created about the knees. For this reason, it is important to keep the knees stationary, and in order to do so, a knee pad is required. Using the link-length diagram, the distance between a 95th percentile males’ knees can be calculated. This will help determine the maximum width of the knee pads. The height of the knee pad is found using the link-length diagram as well, taking the ratio of the bottom of the foot to the knee for both the 5th percentile female and 95th percentile male. Making the pad large enough will allow the majority of the population to be able to use it, without having to adjust the kneepad.
To prevent the user’s feet from slipping while they are using the standing table, a foot plate is used. The surface of the plate is an anti-fatigue mat, which are designed to reduce fatigue from standing for long periods on hard surfaces. The mat also serves as traction for the user, to prevent them from slipping. A back stop is also used on the foot plate to prevent slipping, with a foam pad used for comfort and protection against the hard surface.
6.3.4 Harness Design
Lifting a patient from a seated position requires supporting the lower back/hip region. To do this safely, a padded harness is used which can slip under and behind the user before they are ready to be lifted. There are different settings of hoops along the straps of the harness which can be placed on the pegs of the lifting arms, which will allow users of different body types to be securely strapped in.
With the knees and feet set in place, and a harness lifting the user from the hips, a moment is created about the knees. This will not only lift the patient upwards, but also force them into the knee pads. Foam with an Indentation Load Deflection (ILD) of 80lbs. is used to help reduce the force placed upon the user’s knees. Calculating the moment created about the knees will determine what the maximum force will be on the system.
The harness used to lift the patient was designed to fit around a 95th percentile male, providing back and side support. Attached to the ends of the harness are straps with rings connected to them. The user can connect the rings to different pegs on the lifting arm (depending on their size), which will then securely hold the patient before standing. Within the harness is a back support, which is flexible but firm enough to provide support for the lower back of the user.
6.3.5 Chest Pad and Table Parameters
When the user is lifted into a standing position, they will be brought into a chest pad. This pad will provide support for the patient, to keep them in an upright position. The size and location of this pad can be determined by once again using the link-length diagram. The chest pad should be no higher than shoulders of a 5th percentile female, while at the same time, provide enough support for a 95th percentile male. The foam used is dense enough to provide firm support for the user, while also compressing to make it comfortable to use.
The height of the table top is adjustable on two supporting arms. The table should be located just below the elbows of the user, which would allow them to reach across the table without over extending their shoulders. The chest pad is attached to the edge of the table which will allow users to lean forward without creating a pressure point against the edge of the table.
This standing table is designed to fit 95% of the population, with a maximum weight limit of 300lbs. The proposed design will allow the nurse or aid to make minimal adjustments for specific residents, providing comfort and support for all users. Not only will the patient benefit from being able to stand periodically, but the employees will also reduce their risk of injury.
7 Customer Needs and Specifications
7.1 Needs and Specifications Overview
As is true of any problem, it is imperative that the team or individual assigned to the task is able to fully comprehend the nature of the issue. Secondly, it is of equal importance that the task force is able to ascertain whether or not the problem, as defined by the customer, is truly the problem that needs to be solved, and not simply the customer’s solution to their real problem.
During the meeting with the customer, it was necessary to clarify that the initial needs presented to the project manager during the fall quarter of 2005 were actually the basic needs of the client which need to be met, and not customer solutions. For a more detailed description of the meeting with the ARC, please refer to “The Five Whys” in Appendix G. Following the meeting with the customer, the team met to write down and quantify the actual customer needs.
7.2 Formal Needs Statements
The following is a list of these needs along with a brief description.
• Adjustable Knee Pads: The knee pads for the table are used to support the knees during the operation of the table. These knee pads should be made adjustable or sized such that they accommodate 95% of the population variances.
• Universal Design: The standing table needs to be universally adaptable in nature, and should follow the general ADA regulations. Universality is, however, limited to adult use.
• Adult Use: The standing table is to be used only by adults and, thus, it does not need to cover the heights and weights of children in its range of adjustability.
• Lifting: The standing table is to aid in lifting the customer from their wheel chair and then putting them back into the wheel chair as required.
• Aided Use: Use of the standing table should not be a completely independent operation as the individual using the table may only use it with the help of an aide. Hence, functional use by a single individual should be impeded as this would prevent misuse, or improper use, of the standing table.
• Work Surface: The standing table should contain a table top or other equivalent large, flat, work surface. The customer can use this table for basic activities such as writing, arts, and crafts. Food use is to be prohibited while in the standing table. The table surface should be made clear, if possible, to allow the user a broader view of their surroundings. The table should be able tilt to an angle of 20 to 30 degrees, with respect to the ground, towards the user.
• Trunk Support: Lateral supports of some type should be a part of the design. This is necessary to prevent the user from falling sideways or backwards while in a standing position.
• Lower Body Support: The standing table design should have lower body support for the individual using it.
• Table Interface: The standing table should be operated by a remote control, preferably corded to prevent loss of the remote.
• Noise Generation: The standing table to should be reasonably quiet. Low motor sounds or hummings are acceptable, but excessive noise and vibration should be avoided.
• Cycle Time: The time for one lifting cycle of the standing table should be approximately 45 seconds.
• Safety/Secure Access: The controls and buttons of the standing table should be out of reach of the individual being lifted. This is a measure of safety to prevent misuse of the standing table or unwanted motion by users fiddling with buttons.
• Power: The table should be self powered with no need to plug the unit into the wall during use. The power source which the standing table uses should be renewable, easy to obtain, and inexpensive.
• Human Interfacing: The table should use a sling to support the customer in the hip area to facilitate lifting of the patient. The straps or the belt used in the standing table should be made adjustable to fit everyone falling within the weight and height ranges of the standing table.
• Transport/Stability: The standing table should be able to move easily across residential floors, carpets, and other surfaces. The table should also include a locking mechanism so that when the table is not being transported, it can easily, and quickly, be put into a stable, stationary state.
• Force Generation: The standing table must be able to support the loads induced while lifting and holding an individual. The table should cater to individual weights between 115 lbs and 280 lbs. 280 Pounds is the official standing table limit.
• Height Ranges: The standing table should adjust to user heights between four feet and eight inches, and six feet three inches.
• Skin Contact: For safety, as well as legal purposes, skin contact must be minimized (ideally zero) to reduce the risk of, and occurrence of, bruises, marks, or discolorations that may occur from long term pressure points.
• Foot Stand: The standing table should contain a place to support the feet of the individual using it. The foot platform will also serve as a measure for safety due to the fact that there is no possibility for relative motion between the table and the user.
• Design Dimensions: The standing table should be minimized in all of its height dimensions. The legs should, ideally, be able to fit underneath larger furniture that it can’t fully encompass within its legs. The maximum height of the table should not exceed 6 feet, while the maximum width should be less than 36 inches (width of a standard residential doorway).
8 Concept Development
One of the longest segments of the design process was the brainstorming and concept selection time frame. As could be expected, a written account of the entire process would be incredibly long. Even an abridged version of the proceedings of this section would take up several pages (as indeed it has) and is not monumentally essential to educating the reader about the final design that was chosen and developed. For this reason, only an excerpt from the complete “concept selection methods” write up is included here. For an in depth explanation of the actual feasibility methods employed, please see Project Feasibility, Section 9. Additionally, a more concise version of the concept selection information is contained in a collection of easy to read charts are included in Appendix H.
8.1 General Concept Development
During the second week of the quarter, the team continued to discuss the general idea of what a standing table is, and began to form a list of questions for the meeting with the customer. The questions generally focused on the areas of how a standing table is supposed to work, and other basic requirements needed to successfully build and design a table. At this point, the team had not yet met with the ARC representative, so brainstorming was limited to general ideas for the project (see list in Appendix H, Section 1). It was noted early on that one fundamental criteria for the design was that the weak link in the completed standing table should be a bit of a failsafe, in and of itself, which would not harm the resident, cause gross rupture, or fail abruptly in the event of a failure. In other words, the weak link should be purposefully designed to fail under certain conditions in order to prevent critical safety components from failing.
8.2 Detailed Concept Development
By the middle of the following week, the team had spoken with the ARC representative, Kristin Quinlan, on the phone and also met in person at an ARC residential house to clarify the ARC’s needs. While at the house, it was possible to analyze a Hoyer lift, which would later be compared against the initial concepts to determine which design would be better for our application. A list of our requirements and guidelines is included in Appendix H, Section 2. Based on the customer’s needs, design parameters began to be set which could be used to create some concepts based on different features. Appendix H, Section 3 shows the initial list of design parameters generated by the team.
The design parameters and customer requirements were then combined to create an objective tree in order to organize different thought process during the initial stages of development. A copy of the objective tree is located in Appendix H, Section 4.
Below is a chart detailing the final concepts chosen for each design feature.
|Feature |Final Concept |
|Power |Batteries |
|Force Generation |Electromechanical Actuator |
|Compact/Foldability |Fluid Drive (cylinders) |
|Main Frame Material |Steel |
|Main Frame Geometry |Two Main Posts |
|Ergonomics |Lower Body Lifting |
|Adaptable |Multi-positional & Sliding supports |
|Safety |Use of Machine only by Aide |
|Interface |Remote Control (corded) |
|Mobility |Casters w/ brake |
|Table Top |Tilting Tabletop |
Figure 4: Final Concept Design Features
9 Project Feasibility
9.1 Feasibility overview
After the brainstorming and “weeding out” sessions, an in depth project feasibility analysis was completed to lend some methodical credibility to the concept selection process. One of the first analyses completed was a Quality Function Deployment, or QFD, exercise. The QFD allowed the team to compare customer needs and their relations to actual design parameters or metrics that can be physically measured. As customer needs can often be lofty ideals or goals, it is important to have some method that allows a team to provide a concrete system of measuring. The completed QFD exercise is located in Appendix E, section 2.
In order to asses the feasibility of the various design created during the brainstorm sessions, two variations of the Pugh method were utilized, including a weighted and non weighted analysis. The first analysis conducted used a simple non-weighted Pugh chart that consisted of five separate concepts along the columns, and the features to be measured, or problems that needed to be solved, (customer needs) listed down the left hand side of the chart. Each customer need could also be grouped into one of four categories: Performance, Cost, Safety, and Aesthetics/Comfort.
9.2 Non-weighted Pugh Analysis
As a team, each concept’s solution to a problem or method of implementing a certain feature was judged against a baseline. For the first analysis, the rating system was kept to a simple, yet effective, set of plus, minus, or zero. Coinciding with the plus, minus, zero scale, visual markers of green, red, and yellow, respectively, were used to facilitate quick comprehension of the chart. The baseline used as a standard was an overhead transfer lift currently in use by the ARC of Monroe County. While its operation, and the function, of the lift is fairly different than that of a standing table, it was the closest tool currently in use by the ARC that partially satisfies their needs.
After the first ranking of the initial concepts, the inferior design aspects of the concepts were rejected in favor of those that performed on a higher level. Using the colored chart, it was quite easy to understand which designs to insert into a second Pugh chart for further analysis. Before a second analysis was done, a pair wise comparison of the customer needs was done in order to provide better resolution to the second analysis. The results from this first Pugh analysis can be found in Appendix E, Section 1.
9.3 Determination of Assessment Weights
By listing the customer needs on the ordinate and abscissa of a chart with all of the needs being repeated along the top and side of the chart, relative weights were determined. As a team, each need was rated as more important, equal to, or less important than the second need it was currently being measured against. Similar to the color scheme used for the Pugh analysis, a simple green, blue, and purple arrangement was selected in order to smooth the tallying process. Upon completion of the “Determination of Weights” exercise, the second Pugh analysis was performed in order to finalize a single concept. A chart detailing the process used to determine weights, as well as the results of the weight determination exercise can be found in Appendix E, Sections 3 and 4, respectively.
9.4 Weighted Pugh Analysis
As with the first the Pugh analysis, five new concepts, different from the initial concepts used to weed out the various design features, were all measured against a baseline. Instead of a simple plus, minus, zero scale, a more defined method consisting of rankings from one to five was employed. The scale had even divisions starting at the bottom with one for “much worse” up to five for “much better”. Three was the equivalent of a zero score with a rank of “equal”.
Unlike the first analysis that clearly differentiated between the brainstormed concepts, the second Pugh analysis simply revealed that the remaining two or three concepts developed were simply a matter of personal preference. The differences between the normalized weighted Pugh scores for all five concepts were only .04 from the best to worst concept. After this point, concepts and designs were chosen purely upon team likes and preferences as all of the choices left equally satisfied the customer needs. Appendix E, Section 5, details the final Pugh Assessment.
10 Base Design and Analysis
As one could surmise simply from the definition of the name of the part involved in the section, the base is the backbone of the standing table. Every part involved in the design of this senior design project either directly, or indirectly, interfaced with, or relied upon, the base for some means of positioning and support.
10.1 General Base Design
As has been mentioned previously, the team had decided, upon review of the customer needs and the Pugh assessments that were completed, that an expandable base was needed. Borrowing from the linear bearing concept developed by 8020 inc., the expandable base consists of a square tube inside of which are mounted two different profile linear bearings. The bearings on the left and right faces of the base are simple rectangular cross sections, while the bearings on the top and bottom of the tube have a T profile. Both bearings are made from ultra high molecular weight polyethylene (UHMWPE). UHMWPE is the same material used by 8020 for their bearing slides due to its low coefficient of friction, impact resistance, and high fatigue life. A standard 8020 1515-LITE slotted aluminum extrusion was chosen to ride on the bearing surfaces. The top and bottom T bearings would help maintain alignment of the 8020 extrusion as it moved in and out of the base. Appendix I, Sections 1 and 2 show the completed base design as well as a detail of the slide-bearing mechanism.
10.2 Fluid Drive System
Now that a design for the actual legs themselves had been chosen and refined, a method of actually expanding the legs had to be devised. Again, borrowing concepts from previous group’s work, a modified pneumatic “fluid drive” was designed. For the 2004-2005 moonbuggy, the human powered vehicle team has used a set of pneumatic cylinders filled with water to control the steering. By pushing on one cylinder, the driver was able to push water to two separate cylinders and control the rate and rotation of the front and back wheels simultaneously. Matthew Bell (Frame Design Team) was a member of the team that built the 2004-2005 moonbuggy.
As proof-of-concept was already readily available, and indeed field proven, all that remained was to derive a set of equations relating travel and force inputs to their respective outputs. Appendix I, Sections 3 and 4 detail the equations used to derive the ratios, and the travel and force ratios as a function of input to output cylinder bore ratios. Ideally, a short stroke input coupled with a low force input is desired. However, as can be seen in charts, the travel and force ratios are inversely related. Thus, the travel ratio was constrained, and the resulting force ratio was checked for feasibility. A ratio of 3.54 was chosen in order to limit the input stroke to six inches, yet achieve an output of 10 inches of travel on the legs.
The two input cylinders (one to expand, one to retract) are mounted on the back of the main supports. The drive cylinders are mounted on the back side of the base. Information detailing the cylinder drive schematic can be found in Appendix I, Section 5. Assuming an input force of 50 lbs, the legs will extend outwards with a force of 14 pounds. If more output force is needed, the brackets holding the cylinders are designed to completely support a 200 lb individual standing on the cylinder. This will give a maximum output force of 56 pounds. Appendix I, Section 6 details different input forces and the correlating output forces and accelerations.
11 Design of the Lifting Mechanism
The most important features of any device to interact with humans are the interfaces between man and machine. On top of that, components that will forcibly move or transport individuals are of utmost importance. For the standing table, the design, dimension, and loading of the lifting mechanism were the determining factors for the sizes and locations of all of the other subsystems.
11.1 Design Challenges
The biggest challenge in creating the lifting mechanism was staying under budget, yet finding an electrically powered device (as chosen from the Pugh analyses) that was strong enough to lift and support a 300 pound individual. To further constrain the project, the mechanism had to comfortable attach to an individual while seated, support them through the entire length of the lift phase, and provide enough support while the user is standing. Additionally, it was desired to keep the mechanisms completely underneath the lower surface of the table throughout its travel.
The different variables that could be constrained, or determined through their association with other parts, included:
• Actuator stroke
• Actuator force
• Mounting point for actuator on frame (X and Y position)
• Lift Arm dimensions
o Overall length
o Length of perpendicular arm “nub”
o Mounting location of actuator (arm length ratios)
o Mounting point for actuator on arm (X and Y position)
• Harness strap length
• Harness mounting point
11.2 Solution Methods
Originally, a mathematical modeling relating the torques, forces, lever arms, and leg angles was generated, but proved to be ineffective. Because only a limited number of equations could be developed, it would have been necessary to constrain several variables in order to determine the ones that remained. However, if the wrong constants were chosen, a solution could be derived mathematically, but it would not have physically satisfied all of the desired constraints. Due to the large number of variables involved, a simple two dimensional 4:1 scale paper model was developed to allow for quicker changing of variable dimensions. Using this method it was possible to, rather quickly and efficiently, determine the necessary dimensions for all of the variables. Only the force of the actuators was set as a constant prior to deriving the additional values needed. Next, a simple link model was created in Solidworks to ensure that the measurements taken from the paper model were accurate. Indeed they were, with only the final model needing only one dimension to be shifted a half an inch upwards and to the right
Running parallel to the Solidworks and paper models was an Excel spreadsheet used to quickly and easily determine the induced strap tensions, torques on the moment arms, and the required arm dimensions needed, assuming the use of 2, 500 pound actuators. Appendix J, Sections 1-4 provide details of the equations used to determine the strap forces and torques created. Sections 5-8 show example calculations for a 300 pound user, the corresponding Mechanism Mechanics chart, as well as the overall torque and force charts covering the entire weight range.
Finally, the flat mechanical models were transformed into a three dimensional model to which the free body diagram forces could be applied, and stresses and factors of safety determined. Due to the fact that most of the components involved in the final lifting mechanism were fairly complex, no hand calculations were done, with the exception of the shoulder bolts, which were loaded in double shear. The rest of the components were tested using the Cosmoworks FEA program, embedded in Solidworks. Details of these analyses can be found in Appendix J, Sections 9-12 including insight into the duty cycle achieved, relevant free body diagrams for FEA analysis, as well as the FEA analyses themselves and hand calculations for pin shear.
12 Circuit Design and Analysis
12.1 Necessary Circuit Requirements
As is true of any electromechanical system, the mechanics are left dead and lifeless without the addition of electrical power. As decided upon during the team concept selection deliberations, a rechargeable battery was chosen as the power source of choice. The battery has a capacity of 12 volts and 26 amp hours. The actuators require a maximum input of 20amps at 12 volts DC. One important aspect of the actuator operation is simultaneous operation of both actuator DC motors. In light of this fact, the motors of the actuators are also going to be connected in parallel to maintain balance in the lifting mechanism. The circuit schematic for this system is given below in figure #, as well as Appendix K, Section 1. A brief description of the batteries and a data sheet may be found in Appendix K, Section 2.
12.2 Circuit Components and Layout
The main components used in the circuit are two double pole double throw (DPDT) relays, a single pole single throw (SPST) lighted switch, two momentary SPST switches, a double pole single throw (DPST) switch, an ABS project box, and of course, black and red 18 gauge wires. The main purpose of the circuit is to provide 20 amps of power to the actuators through a corded remote control. The use of the two relays allows the user to switch power to the actuators, using the momentary SPST switches, without passing 20 amps through the hand piece. The lighted SPST switch is a safety device that allows the user to lock out the remote when not in use, or for emergency purposes, kill power to the remote during operation, if needed. The DPST switch is used to disconnect both the hot and ground wires attached to the battery to effectively disconnect the batteries from everything when not in use.
As per regulations regarding the design of a powered standing lift, an emergency switch has been inserted which is separate from the emergency button on the remote. This switch has the capacity to handle 20 amperes of current and will be used to disconnect the batteries from all connections in a hurry.
The surge currents of the actuator motors were taken into account as there is the possibility of a power spike during the initial start up of the system. Thus batteries were chosen to be able provide a maximum capacity of 24 amp hours rather than the specified 20 amp hours.
A wiring schematic for these parts can be found in Appendix K, Section 3.
13 Leg Design and Analysis
In order to translate the conceptual standing table model into a working model, a design analysis was completed. These analyses would either add credibility to the design or negate it in the case of failure. A force analysis was performed in order to determine the dimension of the main and secondary frame support, the legs and the casters.
13.1 Free Body Diagram and Solutions
To determine the size of the front and rear casters needed to support the standing table, the following beam was analyzed.
The force applied is equal to the weight of the standing table and the force exerted by a 300 pound person. The moment is generated as the individual leans against the chest pad support (assumed leaning angle of 5 degrees). From this, the reactions (R1 and R2) were found to be 184.741b and 15.28lb respectively. Casters were sized at 3” diameters in order to support these forces, as listed by the manufacturer's specifications.
The dimension of the legs the casters would be attached to was determined mainly by the size of the interface to the leg attachment for the legs inside the base. Because the design would implement a T-slotted aluminum extrusion expandable leg, the caster legs would need to connect to this leg. Therefore, the outer dimensions of the legs were chosen to be equal to those of the T-slotted leg (1.5inx1.5in). The thickness of the cross section was chosen by investigating what standard profiles were commercially available. A stress analysis was completed to verify if a leg of this dimension would actually sustain the loading applied to it, and was determined to be safe.
The complete analysis, including moment and shear diagrams can be found in Appendix L.
14 Table Top and Support Design and Analysis
14.1 Free Body Diagrams and Solutions
The main and secondary supports were designed to be space efficient, yet also be able to support the loading from the actuator and the loads applied to the pads. The following loading scenario was analyzed (assumes a 300 pound individual and worse case loading).
From this it was determined that the moment and reactions( R1 and R2) were –8718.25lb-in and 278lb and –117lb respectively. The total stress is –10,281 psi. The part will not fail under this loading as the yield stress of the steel being used is 39,000 psi.
The main support and secondary support were designed to be telescoping and interface through a set of pins. To test the stability of this arrangement, it was necessary to determine the shear stress in the pins which are in single shear. The shear stress on the pins is 407.4psi. This value is less than the manufacturer specified maximum of 42,600 psi. The complete FBD, as well as the solutions can be found in Appendix M.
Finally, it was important to determine the stress on the tabletop support to ensure that the loads induced would not cause failure. The main force exerted on the tabletop comes from the chest pad mounted to the front of the quarter-round 8020 extrusion surrounding the Lexan table top. The stress generated is approximately 3.3 psi, which is considerably less than the maximum stress of 35, 000psi that the table material is capable of withstanding. For more detailed information and FEA analysis results, please see Appendix N.
15 Product Strengths and Weaknesses
As is true with any product, choices must be made due to time, group abilities, the current state of technology, and of course, cost. Senior design teams are certainly not exempt from any of the above. Therefore, the following will provide the reader with a sense of where the standing table excels, and where it may not be as notable as other commercial designs, or even other aspects of the team’s own design.
Product Strengths:
• Semi-Automatic Operation (minimal user input required)
• Renewable Power Source
• Ability to expand legs from 30” to 50” to encompass chairs
• “One Step” leg expansion
• Clear impact, scratch, and UV resistant table top
• Smooth table top protective frame
• Quick Adjust table height and tilt angle
• Easy setup and teardown for travel
• Lifting capacity up to 300 pound individual
• Accommodates users from 59.8” to 73.6”
• Quick locking casters
• High factor of safety on all parts
• Ergonomic pad and sling system
• Intuitive design and user interface
Product Weaknesses:
• Cannot support bariatric patients
• Won’t fit around or underneath large, low slung couches (competitor’s designs can not fit around small couches either)
• Not appropriate for child/junior patients
• Limited, large-scale upper body support
• Battery is reasonably heavy (18 lbs)
• Doesn’t completely fold up (problem affects competitor’s designs as well)
• Limited chest pad adjustability
• Actuator DC motor surfaces may become hot if overused (operator instructions discourage use exceeding a 15% duty cycle)
• Risk of electric shock if table is misused (operator instructions detail correct and proper usage and charging procedures)
16 Method of Operation
16.1 Operating Instructions
As is true with any device, a machine will only function as well as the user knows how to operate it. No matter how well conceived, designed, and manufactured a product might be, customer education is the key to successful use, and a satisfied customer. Below is a linear list of the steps that should be enacted in order to obtain the best results from the standing table.
• First, make sure the battery has been fully charged. The battery can then be inserted into the designated holder in the standing table if it was removed for charging.
• Manually move the table to where the patient is sitting.
• Press the cylinder that is currently in the up position (the cylinder marked extend) downward in order to extend the legs such that it can fit around the patients current chair.
• Wheel the table closer to the patient until their knees are touching the knee pad and their feet can be firmly planted on the footrest.
• Lock the two back wheels to ensure the standing table is steady for lifting.
• Slide the lifting harness behind and underneath the patient. Make sure that the patient is comfortable and aware of the actions that occur during the lift phase.
• Attach each strap of the harness to the lifting arms by placing a ring on the harness onto a peg on the lifting arm. The size of the patient will determine which ring and peg should be used, to ensure a secure harness fit.
• Flip the main power cutoff switch, if it has not already been, to the one position to connect the battery to the circuit.
• Using the red button on the side of the remote, power up the remote and prepare for use.
• Using the switches on the remote, red for up and black for down, activate the actuator arms to lift the patient into a standing position. Pressing down at any time will lower the patient, and releasing the button will leave the patient in their current position.
• Once the patient is standing, adjust the height of the table, using the quick release pins, so that it best suits the patient (table should be between elbow and waist height). If the patient would prefer to use a titled table, the aid can adjust the angle of the table by loosening both locking handles.
• Then tighten both handles to secure table at desired angle.
• To reseat the patient, follow the same procedure of ensuring a tight harness fit, power up the system, and using the same remote, lower the patient into a chair.
• Unhook and remove the harness.
16.2 Safeguards and Warnings
CAUTION! For safety purposes, both the battery disconnect switch and the remote power switch should be left in the OFF position while not in use. Failure to adhere to this safety procedure could result in undesired lift operation or battery discharge. Always disconnect power before attempting to clean or service the standing table. Battery is capable of delivering more than 20 amps of power during operation. Under no circumstances, should anyone attempt to alter or modify the existing circuit layout as improper modification may result in compromising of built in safety features or electrical shock. Actuator DC motor surfaces may become hot during extended or repeated use. A built in thermal trip sensor will shut off the actuators for 15 minutes during an overheat to prevent damage to the system. Actuator should not be run continuously, but should be restricted to complete up and down cycles when needed.
Any injuries resulting from negligent use or failure to adhere to the above listed procedures and cautions are not the liability of the design team. The user is responsible for making themselves familiar with all procedures and cautions. Any questions may be directed to the design team through the Mechanical Engineering Department at Rochester Institute of Technology.
Appendices: Table of Contents
Appendices: Table of Contents 55
Appendix A – Project Proposal 57
Appendix B – Mission Statement 60
Appendix C – Team Values and Norms 63
Appendix D – Gantt Chart 64
Appendix E – Feasibility 65
Section 1 – Pugh Analysis 65
Section 2 - QFD 66
Section 3 – Determination of Weights 68
Section 4 – Determination of Weights Results 69
Section 5 – Weighted Pugh Analysis 70
Appendix F – Ergonomics 71
Section 1 – Anthropometric Data Table (Height) 71
Section 2 – Relative Body Dimensions 71
Section 3 – Generic Body Weights 72
Section 4 – Segment Weights of 300lbs. Person 72
Section 5 – FEA Analysis of Footplate 73
Appendix G – The Five Whys 74
Appendix H – Concept Generation 78
Section 1 - Brainstorming 85
Section 2 – Requirements, Needs, and Guidelines 85
Section 3 – Design Parameters 86
Section 4 – Objective Trees 87
Section 5 – Morphological Charts 91
Section 6 – Individual Concepts 93
Section 7 – Team Preliminary Concepts 94
Section 8 – Final Morphological Chart 95
Section 9 – Final Concepts 96
Appendix I – Pneumatic Fluid Drives 97
Section 1 – Solid Model: “Extend” Drive Cylinder 97
Section 2 – Solid Model: Fluid Drive/Leg Interface 98
Section 3 – Fluid Drive Ratio Formulas 100
Section 4 – Force and Travel Ratios for Cylinder Bore 101
Section 5 – Fluid Drive Schematic 102
Section 6 – FEA Analysis of Drive Cylinder Assembly 103
Section 7 – Stress Lift Curves of Base Assembly 104
Appendix J – Force Determination for Lifting 105
Section 1 – Body Segment Weights 105
Section 2 – Strap Forces 105
Section 3 – Angle and Force Determination 106
Section 4 – Torque Equation 107
Section 5 – Force and Torque Summary 107
Section 6 – Forces and Torques Graph 108
Section 7 – Torques Generated by Individuals 109
Section 8 – Force Required to Lift Individuals 110
Section 9 – Actuator Duty Cycles 111
Section 10 – Free Body Diagram of Lift Arms 111
Section 11 – FEA Analysis of Lifting Arm 112
Section 12 – Pin Shear Calculations 113
Section 13 – Stress Life Curves for Lifting Assembly 114
Appendix K – Table Electronic Systems 115
Section 1 – Circuit Schematic 115
Section 2 – Battery & Charger 116
Section 3 – Wiring Diagram for Circuit 120
Appendix M – Force in Main & Secondary Support 125
Appendix N – Stress in Table & Bolt 128
Appendix O – Bill of Materials (BOM) 129
Appendix P – Assembly Plans 131
Appendix Q – Business Plan Outline: Standing Table 134
Appendix R – Engineering Drawings 147
Appendix A – Project Proposal
2005/2006 RIT Multidisciplinary Senior Design Project Proposal
|Project Name and Number |Updated |
|06205 Standing Table |12-15-05 |
|Sponsor | |
|Arc of Monroe County | |
|Sponsor Contact |Phone |Email |
|RIT Contact |Phone |Email |
|DeBartolo |475-2152 |eademe@rit.edu |
|Project Start Quarter 052 (Winter 05-06) Finish Quarter 053 (Spring 06) |
|Project Overview |
|(please provide a brief background and description of the project) |
|A standing table is a device that allows individuals unable to bear weight alone to stand with partial or full weight support. A standing |
|table also allows users to independently transfer from a seated position in a wheelchair or bed to transfer to another seating location, or a |
|standing position. Such a device would greatly improve the self esteem and independence level of these consumers as they are no longer fully |
|reliant on others to stand up or move about. Additionally, a standing table is able to improve poor muscle tone and increase the range of |
|motion of certain joints that are not normally used. A table that is capable of folding or collapsing would be innovative as existing |
|standing tables are quite large, require a great deal of space, and are more suited to commercial living centers rather than standard homes. |
|Some existing designs for standing tables are as simple as a sturdy walker with a wide base and gripping handles, while other more flexible |
|designs utilize actuators to assist the individual who is not capable of pulling themselves out of a chair. The senior design team will meet |
|with the members of the ARC home and the ARC physical therapist. The team will also customize the design of the standing table to the |
|specific needs and sizes of the individuals currently living in the home. As part of the learning process, students will expand their |
|knowledge of the biomechanics of people with different physical disabilities and apply basic manufacturing procedures. |
| |
|Project Success Factor Checklist |
|(x) The project is important to the sponsor, but is not on the |Comments |
|critical path. |The standing table would lessen the strain on ARC workers and improve |
| |the condition of ARC community members. |
|(x) There is an advocate in the sponsor’s organization committed to |Advocate Contact Information |
|the project success. |Kristen Quinlan, ARC Representative |
| |585-747-7509 (Cell) |
|(x) There are no intellectual property or other legal concerns that |IP Status |
|will interfere with the student’s course commitments (reports, |( ) a non-disclosure agreement will be required |
|presentations, web site, poster) |( ) a provisional patent application has been files |
| |( ) a full patent application has been filed |
| |( ) a patent has been issues |
| |(X) students may retain their IP rights as individuals |
| |( ) students will be required to assign IP rights to sponsor |
|(x) The success of the project requires the skills of at least two |Estimated Number of Students Needed |
|engineering disciplines | |
| |Computer Engineering ________ |
| |Electrical Engineering___1____ |
| |Mechanical Engineering__4___ |
| |Industrial & Systems Engineering ___1____ |
| |Industrial Design _________ |
| |Business ___________ |
| |Other ______________ |
|Proposed Team Members Major Email Has this individual agreed to join the team? |
|1. Craig A. Hudson (Manager) ME cah8460@rit.edu Y |
|2. Matthew Bell ME mab4837@rit.edu Y |
|3. Jeff Matusik ISE jrm2444@rit.edu Y |
|4. Kahamala Morgan ME ktm1016@rit.edu Y |
|5. Maria Spagnola ME mes4381@rit.edu Y |
|6. Aditya Srinivas EE axs1048@rit.edu Y |
| |
|The improvement team will be provided with the following: |
|(x) Background Information: |Comments |
|( ) data, |Team will meet personally with the ARC physical therapist to go over |
|( ) drawings, |critical design factors and patient needs. Team will be supplied with|
|( ) reports, |Project Readiness Package from Design Project Management. |
|(x) other: See comments | |
|( ) Requirements Document, including |Comments |
|qualitative performance goals |Specific requirements will be determined by the Project Manager during|
|quantitative performance goals |scheduled meetings with the ARC therapist. |
|operating environment | |
|human interfaces | |
|interfaces with other systems | |
|physical & aesthetic requirements | |
|design constraints | |
|(x) Security Clearance: See comments |Comments |
| |Team must complete IRB form to receive institute permission to work |
| |with human subjects |
|( ) Lab or Office Space: |Comments |
| | |
|( ) Computers & Software: |Comments |
| | |
|( ) Equipment: |Comments |
| | |
|( ) Other Essentials: |Comments |
| | |
| |
|Desired Outcomes: |
|( ) concept sketches |Comments |
|( ) prototype drawings |Purpose of project is to provide the ARC with a usable product after |
|( ) production grade drawings |20 weeks |
|( ) prototype | |
|(x) fully functional, ready to use model | |
| | |
| | |
| |
|Funding Considerations & Budget |
|(note: Sponsors are responsible for purchasing, and out-of-pocket expenses, such as project materials, equipment, and external fabrication |
|costs.) |
| |
|The standing table project is part of the “Design Projects to Aid People with Disabilities” program. These projects are sponsored by an |
|umbrella grant from the National Science Foundation. Design teams are required to track their individual expenses as the NSF grant is being |
|managed under a single account. |
Appendix B – Mission Statement
P06205 - Standing Table
|1.0 Product (Project) |The goal of Senior Design Team with project #P06205 is to design and build a standing table to assist |
|Description |disabled people living in the Monroe County area ARC homes. A standing table is a device used to help |
| |patients, incapable of standing on their own, lift themselves from a seated position to a standing |
| |position. |
|2.0 Scope Limitations |2.1 Product will be defined and limited by the Preliminary Product Specifications to be determined and |
| |provided by the team. 2.2 Funds for all supplies and labor should not exceed a |
| |budget of $1,500. |
| |2.3 Product shall utilize available OEM subsystems and assemblies where applicable. |
| |2.4 Product shall work safely within a disabled person’s home. 2.5 Product size and |
| |weight shall be minimized to increase mobility and usefulness. |
| | |
| |2.6 Design shall assume low volume manufacturing cost considerations. 2.7 Design team should |
| |use a Solidworks as their main CAD package. |
|3.0 Stakeholders |3.1 Senior Design team members of project P06205. |
| |3.2 Dr. Elizabeth Debartolo, Ph.D. 3.3 |
| |ARC community members |
| |3.4 ARC therapist |
|4.0 Key Business Goals |4.1 Product should be cheaper than existing commercially available models. 4.2 Product shall not |
| |increase liability of stakeholders |
| |4.2.1 No financial costs shall be placed upon the stakeholders, all monetary |
| |needs shall be covered by supplied funding |
| |4.2.2 Product shall not noticeably increase therapist’s workload in the form of preventative maintenance|
| |of which neglect of said maintenance, may cause product failure and patient injury |
| |4.2.3 Potential for and the number of ways in which a patient could possibly be injured will be |
| |minimized via adherence to common sense and industrial safety practices. |
| |4.3 Product maintenance costs should not exceed cost of the product over the useful life of the product |
| | |
| |4.4 Operation of product shall not measurably increase operating costs of the ARC. |
| |4.5 Product value should exceed initial investment. |
| |4.5.1 Final product value shall be determined based upon cost of materials, amount of time spent |
| |designing, and the amount of time spent fabricating. |
| |4.5.2 Time spent fabricating prototype shall be considered an upper limit for theoretical production |
| |times of additional units |
|5.0 Financial Analysis |See attached Bill of Materials |
|6.0 Primary Market |6.1 Product design and operation shall appeal to primary disabled users. |
| |6.1.1 Appeal shall be based upon ease of use of unit, noise output of unit (minimize), bulkiness |
| |(minimize) and ability to easily move/transport |
| |6.2 Product operation shall decrease workload of ARC social workers. |
| |6.2.1 Patients shall be able to, with the help of the product, lift themselves from a seated position to |
| |a standing position with minimal aide from therapist (patients will not use machine unsupervised). |
| | |
| |6.3 Product shall showcase student ability and gained knowledge to the RIT ME |
| |faculty. |
| |6.3.1 Product will require significant application of topics learned including Statics, Dynamics, Design|
| |of Machine Elements, Mechanics, ergonomics, human factors, and design of circuits and electrical systems.|
| | |
| |6.3.2 Prototype fabrication shall demonstrate student’s proficiency with modern production machines and |
| |processes. |
| |6.4 Project will appeal to senior engineering students as exciting and challenging. |
| |6.4.1 Students will be able to apply their academic experience in a team setting |
| |6.4.2 A working prototype will increase a student’s confidence level in apply academic knowledge |
| |6.4.3 Product design will be such that it is not easily designed by a single student in a short amount |
| |of time but rather, requires due diligence to accomplish while allowing students a chance to push their |
| |individual limits. |
| |6.5 Project will satisfy parental desire for student success. |
| |6.5.1 Final design shall be such that, prior to their schooling, students would not have been able to |
| |as effectively and efficiently designed such a product. |
| |6.5.2 Project shall be such that students are able to achieve grades that directly reflect their |
| |abilities and mastery of academic application |
|7.0 Secondary Markets |7.1 Product may be adapted to high volume commercial production for sale to disabled persons homes and |
| |suppliers of medical equipment. |
| |7.2 Product may be adapted for use in recreational pools where pool transfer equipment is needed. |
| | |
| |7.3 Limits placed upon secondary market possibilities |
| |7.3.1 Product is not designed for use by young persons |
| |7.3.2 Product is not designed, nor should be adapted, to lift and support patients in excess of 300 |
| |pounds. |
| |7.3.3 Product is not designed for use outside of a group home or therapy center where immediate help is |
| |available in case of an emergency. |
|8.0 Success Qualifiers |8.1 Technological Attributes |
| |8.1.1 Product shall be able to lift larger patients up to, and including 300 pounds. |
| |8.1.2 Product shall be automated to ease patient transition |
| |8.1.2.1 Different type of transitions will include a seated to standing transition as well as a seated |
| |to seated transfer, such as from a wheelchair to a bed or toilet. |
| |8.1.3 Design shall be manufacturable in-house at RIT by student team members. |
| |8.1.3.1 Manufacturing facilities in building 9 (mills, lathes, drills) as well as the Brinkmann lab in |
| |the CIMS building (CNC, EDM) may be used for manufacturing of necessary parts. |
| | |
| |8.2 Budget and Economic Attributes |
| |8.2.1 Product shall be affordable for low budget operations (namely the ARC) |
| |8.2.2 Raw materials shall remain within budget |
| |8.2.2.1 Materials used in design shall be chosen such that they are easily obtained and are not |
| |excessive in cost (choosing lower grade alloys where expensive high grade alloys are not necessary, etc) |
| |8.2.2.2 Materials shall be chosen such that machining of said materials does not require special |
| |tooling or processes or require the manufacturer to provide additional services necessary to supply the |
| |desired materials. |
| |8.2.2.3 Material scrap shall be minimized. When possible, like material types and sizes will be used |
| |in design to minimize the total number of different stock pieces that must be purchased. |
| |8.2.3 Product manufacturing should utilize existing shop equipment and minimize necessary tooling and |
| |fixturing. |
| | |
| |8.3 Performance Attributes |
| |8.3.1 Operation shall be manageable by a single person. |
| |8.3.2 Product shall decrease patient transfer times from standing to sitting and vice versa. |
| |8.3.3 Product shall support a patient for extended periods of time comfortably |
| | |
| |8.4 Scheduling Attributes |
| |8.4.1 Design team shall meet with ARC therapist and ARC home members to tailor the end product to their |
| |personal needs. |
| |8.4.2 Product shall be designed within 10 weeks. |
| |8.4.3 Product shall be manufacturable within an additional 10 weeks. |
| |8.4.4 Product shall be tested and shown to be safe within the 10 weeks |
| |of manufacturing. |
|9.0 Success Winners |9.1 Technological Attributes |
| |9.1.1Product should meet or exceed current weight limits of like existing competitor products (not to |
| |include extra-heavy duty machines designed specifically to lift patients in excess of 400 pounds) |
| |9.1.2 Product should meet or exceed safe transfer rate of patient from a seated to a standing position |
| |that existing products currently have (approximately 45 seconds per transfer, not including harnessing |
| |operations). |
| | |
| |9.2. Budget and Economic Attributes |
| |9.2.1 Product should be cheaper than similar existing competitor products. |
| |9.2.2 Product should use proven technology to reduce manufacturing and maintenance costs. |
| | |
| |9.3 Performance Attributes |
| |9.3.1 Operation should be intuitive and easier than existing designs. |
| |9.3.2 Product should have a fatigue life sufficient to exceed the life of existing competitor products. |
| | |
| | |
| |9.4 Time Attributes |
| |9.4.1 Lead time for additional units should be half the lead time for the original unit |
| |9.4.2 Modification of units should be able to be completed with a 10 week period to allow for additional|
| |work to be completed by other senior design teams. |
|10.0 Innovation Opportunities|10.1 Product design should be such that patentable ideas can be utilized to form a business or sold to |
| |an existing medical supplier. |
| |10.2 Product shall allow students insight into the design process of a product from conceptualization to|
| |manufacture. |
| |10.3 Project shall give students insight into the design and use of simple assistive medical devices. |
| |10.4 Project experience should prepare students for a career in the medical devices field. |
Appendix C – Team Values and Norms
P06205 – ARC Standing Table
1. Each team member agrees to attend all regularly scheduled meetings, show up on time and stay for the duration of the meeting unless prior arrangements have been made.
2. If a member is unable to attend a meeting, all work that was due to be completed for that meeting will be delivered to a second team member or their mail folder.
3. All members of the team agree to be prepared to the best of their ability to share their completed work and learn during group meetings.
4. Team members agree to respond to emails promptly, within 24 hours during the week or, within 48 hours on weekends.
5. Each group member agrees to be respectful of others ideas, property, and each other.
6. Members of the group agree to work hard and do their best, but to take on a feasible work load that they can complete well within the allotted time.
7. Team members agree to complete work on time.
8. Team members agree to keep organized individual notebooks as well as contribute to the team binder.
Team Signatures:
__________________________________ ________________________
Craig A. Hudson (Team Manager, ME) Date
__________________________________ ________________________
Maria Spagnola (Co-Lead Engineer, ME) Date
__________________________________ ________________________
Aditya Srinivas (Co-Lead Engineer, EE) Date
__________________________________ ________________________
Matthew Bell (Mechanical Engineer) Date
__________________________________ ________________________
Jeff Matusik (Industrial Engineer) Date
__________________________________ ________________________
Kahamala Morgan (Mechanical Engineer) Date
Appendix D – Gantt Chart
|Standing Table Schedule | | | | | | | | | |
| | |
| |1 |2 |
|Trunk Support |0.958 | |
| | | |
| | | |
|Lower Body Support |0.958 | |
|No Skin Contact |0.958 | |
|Secure Access |0.917 | |
|Stable Platform |0.917 | |
|Stand Alone System |0.625 | |
|Universal Design |0.583 | |
|Lift Heavy Patients |0.458 | |
|Adult Use |0.417 | |
|Remote Access |0.292 | |
|Work Surface |0.250 | |
|Quick Transfer |0.208 | |
|Efficient |0.125 | |
|Quiet |0.083 |Least Important |
Section 5 – Weighted Pugh Analysis
|Feature |Relative Weights|Final 1 |Final 2 |Final 3 |Final 4 |
|Universal Design |0.583 |4 |4 |4 |4 |
|Adult Use |0.417 |3 |3 |3 |3 |
|Lift Heavy Patients |0.458 |4 |3 |4 |3 |
|Work Surface |0.250 |5 |5 |5 |5 |
|Trunk Support |0.958 |5 |5 |4 |4 |
|Lower Body Support |0.958 |5 |5 |4 |4 |
|Remote Access |0.292 |3 |3 |3 |3 |
|Quiet |0.083 |3 |3 |3 |3 |
|Quick Transfer |0.208 |4 |4 |3 |3 |
|Secure Access |0.917 |4 |4 |4 |4 |
|Stable Platform |0.917 |4 |4 |5 |5 |
|No Skin Contact |0.958 |4 |4 |4 |4 |
|Must be Safe |1.000 |3 |3 |3 |3 |
|Stand Alone System |0.625 |3 |3 |3 |3 |
|Efficient |0.125 |4 |4 |5 |5 |
|Total Score | |34.75 |34.2917 |33.6667 |33.2083 |
|Normalized Score | |1 |0.99 |0.97 |0.96 |
Appendix F – Ergonomics
Section 1 – Anthropometric Data Table (Height)
[pic]
Anthropometric data tables for a standing and sitting posture based on the work of Pleasant
Section 2 – Relative Body Dimensions
|Relative Dimensions of Avg Human Body (in inches) |
| | |Ratio |5th female |95th male |Avg |Std Dev |
|ground to knee |0.285 |17.04 |20.98 |19.01 |1.97 |
|ground to hips |0.53 |31.69 |39.01 |35.35 |3.66 |
|ground to elbow |0.63 |37.67 |46.37 |42.02 |4.35 |
|ground to chest |0.72 |43.06 |52.99 |48.02 |4.97 |
|ground to shoulder |0.818 |48.92 |60.20 |54.56 |5.64 |
|width of hips |0.191 |11.42 |14.06 |12.74 |1.32 |
|chest to grip reach | |17.5 |21.9 |19.70 |2.20 |
Section 3 – Generic Body Weights
Breakdown of Generic Body Weights
|Grouped Segment |% of Total Body Weight |Individual Segment |% of Grouped Segment |
|head and neck |8.4% |head |73.8% |
| | |neck |26.2% |
|torso |50.0% |thorax |43.8% |
| | |lumbar |29.4% |
| | |pelvis |26.8% |
|total arm |5.1% |upper |54.9% |
| | |forearm |33.3% |
| | |hand |11.8% |
|total leg |15.7% |thigh |63.7% |
| | |shank |27.4% |
| | |foot |8.9% |
Section 4 – Segment Weights of 300lbs. Person
Breakdown of 300 lb Individual
|Segment |% of Total Body Weight|Weight (lbs.) |
|Head and neck |8.40% |25.20 |
|Torso |50% |150.00 |
|Total Arm |5.10% |15.30 |
|Upper Leg (Thigh) |10% |30.00 |
|*Total Body Weight = 300lbs. | |
References:
Rudolfs Drillis and Renato Contini. Body segment parameters. Technical Report 1166-
03, New York University, School of Engineering and Science, Research Division, New York under contract with Office of Vocational Rehabilitation, Department of Health, Education and Welfare, September 1966.
Section 5 – FEA Analysis of Footplate
[pic]
FEA Analysis of Footplate While Lifting 300lbs. Person
Appendix G – The Five Whys
Copy of the “Five Whys” paper, as Presented in Senior Design 1
The Five Whys:
The Why:
Whenever a firm or individual sets out to design something, either for themselves or for someone else, it is important to find out exactly what is needed or wanted. While the customer usually knows what they want, they often have a hard time conveying their actual wants to the designers. In order to effectively design a device or system that will satisfy the customer with minimal frustration and setbacks to the design group, it is paramount that the actual customers needs be separated from the customer’s preconceived notions of how to solve the problem. The best way to form this separation is to ask the “5 Whys”.
For our design team, the ARC of Monroe County approached us and requested that we design a standing table. A lot of their patients are wheelchair bound and are unable to stand up by themselves. Sometimes being blatantly obvious is the best way to get some information and, hence, our first why was the most simple, “Why do you need a standing table”. The ARC stated that it is important to have a standing table so that patients are able to stand by themselves unaided and unattended. Logically, this incited the question of “Why is standing good for the patients”. Humans, by nature, are upright beings and standing is an important part of maintaining a healthy body. Standing, even with partial or full weight bearing by a machine, helps to increase the patients muscle tone as well as increase circulation. Also, by nature of extended their body, their joints are flexed and used while their cardiovascular system is given a slightly heavier load. While it does not compare much to traditional exercise of non-disabled persons, for a wheelchair bound patient, it is the equivalent to them.
Now that the actual need for a standing table had been solidified, we were curious to know why they approached us to design a standing table, as several commercial designs already exist. Currently, the ARC has one powered lift, which is similar in nature to a standing table but is used only for transfers, not for standing. When questioned about the need for a table versus the lift, it was stated, as before, that it is important for the patients to remain standing for a certain amount of time, and that the current design of the powered lift had several defaults. Mainly, there were some adjustability and maintenance issues that had become a bit of a nuisance when using the device.
Two of the main needs that the ARC had for a new standing table is that it also must be smaller, and must be customized for their patients. Of course, these were responded to with a polite “why?”. Their current lift, manufactured by Arjo, does have a few size imposed limitations inherent to the design. First, it often has trouble fitting around, or under in the case of the legs, couches in such a way that allows them to access patients sitting on a couch. Additionally, the overhead lift design often limits the height to which they can place a patient as it sometimes hits the ceiling. Finally, the ARC needs a custom table because, quite simply, they are a not-for-profit company that does not have the necessary funds to appropriate such a standing table, or hire an independent firm to design one. By allowing RIT to use NSF designated funds, they can not only obtain a product especially customized, and therefore useful, to them, but they can obtain it free of charge.
By asking five whys, in five different ways, it was determined that the ARC does, in fact, require RIT to design a standing table. Rather than a standing table being a preconceived solution to their problem, it is simply a need. Given the state of the ARC patients, there really is no other way to encourage them to stand that does not put both the patient and therapist at risk.
The How:
A difficult task, as discussed before, is understanding the needs and requirements of our customer. The expectations for the designers always tend to be a little confusing. To reduce this gap to the minimum, we basically brainstormed with the customer by asking as many questions as possible that came into our mind. The first few questions covered a big picture and a sort of debate was created out of it.
For example, the first few questions and discussions we had with our customer was who they are, what they do, why did they choose us, why do they need a standing table, do they currently have a standing table, if yes, what is the problem with its design, what more are you looking out for etc. As and when the questions were being answered, we kept getting more and more specific giving us a much better picture of what our customer’s expectations are. We took advantage of the opportunity to sit on the machines they are currently using to aid the people at the ARC like a Tempo Combi.
The Tempo Combi is a machine used to lift the patient from the wheel chair by shifting weights and to transport them to a different location. The levers involved in it, its working mechanism, the power used by it, etc. were analyzed by us, which gave us a clearer picture of what needs to be done, and how it has been done in the past.
The basic mode of asking questions was in one word – brainstorming. We tried to squeeze as much information out of the ARC as possible by asking simple yes and no and then getting further into details, and getting demonstrations until we had nothing more to ask. Following this, we met a couple of residents of ARC which gave us a basic understanding of what kind of people are going to be using our design we are in the process of creating. More meetings shall be held in the future with ARC representative to get more information.
Appendix H – Concept Generation
Detailed Account of Concept Generation and Selection Process
During the second week of the quarter, the team continued to discuss the general idea of what a standing table is, and began to form a list of questions for the meeting with the customer. The questions generally focused on the areas of how a standing table is supposed to work, and other basic requirements needed to successfully build and design a table. At this point, the team had not yet met with the ARC representative, so brainstorming was limited to general ideas for the project (see list in Appendix H, Section 1). It was noted early on that one fundamental criteria for the design was that the weak link in the completed standing table should be a bit of a failsafe, in and of itself, which would not harm the resident, cause gross rupture, or fail abruptly in the event of a failure. In other words, the weak link should be purposefully designed to fail under certain conditions, and should not be a component critical to safety.
By the middle of the following week, the team had spoken with the ARC representative, Kristin Quinlan, on the phone and also met in person at an ARC residential house to clarify the ARC’s needs. While at the house, it was possible to analyze a Hoyer lift, which would later be compared against the initial concepts to determine which design would be better for our application. A list of our requirements and guidelines is included in Appendix H, Section 2. Based on the customer’s needs, design parameters began to be set which could be used to create some concepts based on different features. Appendix H Section 3 shows the initial list of design parameters generated by the team.
The design parameters and customer requirements were then combined to create an objective tree in order to organize different thought process during the initial stages of development. A copy of the objective tree is located in Appendix H, Section 4.
In order to begin choosing which concept would best satisfy the customer requirements, the team listed important features and all of the possible combinations of features from the morphological chart from prior brainstorming and requirements lists. Features were divided up into exclusive and non-exclusive concepts, showing that some features would work well together and there could be a few different features within the same design feature category. These non-exclusive concepts could all be incorporated together on a standing table, while for other categories, the concept that we decided to go with would have to be the only one utilized for that feature. Appendix H, Section 5 contains our tables of the exclusive and non-exclusive features developed by the team.
In order to continue to work towards selecting a final concept, each member of the senior design group created two concepts that were a combination of what each member thought would be the best features for a standing table. Appendix H, Section 6 contains individual concept ideas.
Following this, the team went through a series of discussions and modeled different tables in order to further break down our list so that it would be possible narrow down the available concepts into a final design. Through team discussions, and through individual concept ideas, exclusive ideas that were deemed to not be feasible for our project were eliminated. With the pared down morphological chart, the team made four preliminary concepts (see Appendix H, Section 7).
From these concepts, it was decided to further reduce the exclusive concepts table from Appendix H, Section 5, and create a newly revised exclusive concept table with three possible concepts. At this point, the number of possibilities for each feature was reduced to a single design for all of the categories except for compact, main frame material, main frame geometry, and adaptable methods. These remaining categories were reduced to two or three potential possibilities. The revised exclusive concepts table can be found in Appendix H, Section 8.
As is evident from the revised exclusive concept table, the team decided to use rechargeable batteries as the power source. These seemed to be the most portable and reusable option for power that the team came up with. Two batteries can be supplied so that one can charge for backup service while the other is in use.
Electromechanical actuators were chosen for force generation due to their uncomplicated and economical nature for lifting heavy loads. Upon further discussion of the winch idea it was found that it could be obtrusive to the person in the standing table.
For the compact category, two options were still being decided between after the initial weeding out of ideas: manually collapsing or hand pump (fluid drive) collapsing. If the device were to fold and collapse manually, there would need to be a certain defined method to do so, and an explanation in an instruction manual of how to physically collapse or fold the standing table such that an aide or staff member of the ARC would be able to learn the process. If we were to use a fluid drive with cylinders to collapse or extend the standing table, this would make putting the standing table away or out of the way less labor intensive. By simply stepping on the end of one fluid cylinder, the ARC aide could easily extend or collapse the entire device.
At this point, it was decided that the main frame of the standing table could be made up of aluminum, 80/20 extrusion, or Cro-Moly steel. The decision of which material would be better to use would depend on strength, weight, and how each could be uniquely used for this application. The decision would have to be made once other decisions, such as desired frame setup, geometry, and features could be decided. After creating initial layouts for the frame, strength and weight needs could be taken into consideration.
The main frame geometry could have been either a space frame with two posts, or a single main post. This decision would depend highly on other options chosen in order to see how the standing table could best be laid out. A space frame with two supports would seem more stable in spreading out the weight of the standing table. A single main post would require less material and everything could be attached in one place, which has the ability to simplify the design and reduce the overall number of parts.
As far as the ergonomics related to lifting a person in the standing table, it was decided that lower body lifting would be the most comfortable, and safest, method of lifting for the given application. Lower body lifting would provide more overall support while allowing for more freedom of movement when a person is being held for an extended period of time. Overhead lifting would be limiting for people of different sizes due to the fact that their whole body would be enveloped by the harness or sling lifting them. From the observations of a Hoyer lift where this type of lifting was utilized, it would be difficult to reach forward and be supported in a way where they would still be able to use the table top effectively. Underarm or torso lifting would support the upper body, but the lower body would be free to move about, which did not appear to be very safe or comfortable. Having lower body support through the lifting motion seemed to be the safest method and would provide the most support, giving the person in the harness confidence in the standing table’s ability to hold them.
The safest and most useful method for making the standing table adaptable was a toss up between using sliding supports or multi-positional supports. Chest and knee pads could be designed in a way that they would be able to move up and down, or in and out, to be comfortable for people of all sizes. In order to do this, the supports for these pads would need to be moveable. If these supports were sliding, a clamp would be used that would allow the pads to be positioned at any place along the pad rails or main beam. Sliding supports would be more adaptable in that it is possible to make smaller adjustments and the user is not limited to pre-positioned points equally spaced apart. As mentioned just before, multi-positional pads would, by design, have a limited number of slots or holes along the pad rail or main beam. A pin system would be utilized in which a pin would be inserted into the slots in order to hold the pads in place. In this case, there would be fewer options as far as where the pads could potentially be located, but it would be safer due to the fact that there would be no way for the pads to slip down while someone was leaning against them, unlike a clamp that may come loose.
For safety, it was decided that the machine would only be operated by an aide or staff member of the ARC house. The aide would be able to use the remote to lift a person from sitting to standing and then, through the series of pads and harnesses involved, the resident would be secure enough such that the aide would be able to leave the side of the resident to attend to other needs within the same room. This way, the resident would not be lifting or lowering themselves and, a qualified individual would help to ensure proper use of the table.
For the interface that would control the lifting or lowering of an individual, it was decided to use a remote control. The remote would have a cord attached to the standing table so that it could be held by the aide if they were to stand next to the resident as they were being lifted, but also ensure that the remote would not be misplaced. This design is similar to the remote used on the Hoyer lift that was observed.
For mobility, the standing table would be on caster wheels. A resident would then be able to be lifted up into a standing position and moved to a location to do an activity, or moved closer to a table to join in with a group. The caster wheels would have a brake integrated into their design so that when the table is in place, it may be held there for safety purposes.
The table top itself should be able to tilt 20 or 30º from horizontal as it is more comfortable to write or do an activity with a small degree of upward tilt while standing. Because of this tilt, it will be necessary for the table top to have a ridge of some sort so that anything placed on the table will not roll and fall off.
In order to reduce the design concepts further, four final team concepts were created that incorporated all of our exclusive concepts listed in the revised concepts table referenced above, and created the table shown in Appendix H, Section 9. This helped to further illustrate the possibilities that were being debated, and helped the team to arrive at a final decision for the feature categories that were still not finalized. The final team concept incorporates the features that best apply to our application, the requirements initially stated, and is also based on the feasibility of each part of the design. This final design concept that we continued to work with is shown below:
|Feature |Final Concept |
|Power |Batteries |
|Force Generation |Electromechanical Actuator |
|Compact/Foldability |Fluid Drive (cylinders) |
|Main Frame Material |Steel |
|Main Frame Geometry |Two Main Posts |
|Ergonomics |Lower Body Lifting |
|Adaptable |Multi-positional & Sliding supports |
|Safety |Use of Machine only by Aide |
|Interface |Remote Control (corded) |
|Mobility |Casters w/ brake |
|Table Top |Tilting Tabletop |
Section 1 - Brainstorming
- lift – lever, fork lift, parallel beam
- power – rechargeable battery, AC interface, DC, pump, compressor
- force generation – screw actuator, hydraulic system, winch, human power, pneumatics
- fold and compact – aluminum, hydraulic assist folding, able to be broken down for storage
- ergonomics – bone adaptation to mechanical loading, leg and shin support system, sling, padding, strap system – minimize sharp edges, pinch points – overhead harness or lower body – foot plate
- how adaptable – sliding components, multi-positional pieces
- stand alone – no cords or need to bolt into place, able to move about
- type of interface – remote, console, trigger locks wheels into place, stickers about how to use, standardized colors
- safety – emergency shut off button, emergency lowering device, travel sensor, in use sensor
- extras – instruction book, cup holder, personalization, safety grips with covers, drawer, automatic shut down if not used for awhile to save battery, radio
Section 2 – Requirements, Needs, and Guidelines
- universal (able to be adjusted for different sizes of people)
- adults only (no children would use our standing table, and no geriatric people)
- 115 – 280 pounds (weight range)
- 4’8” – 6’3” (height range) – average height is about 5’4”
- resident would be coming out of a wheelchair (lifted from sitting position)
- resident would not necessarily have a lot of function with their hands
- staff would be present at a minimum of when the resident is in motion on the standing table – resident would be secure enough that aide could walk away to help someone else once the resident is securely standing
- security and stability very important (for safety).
- residents could have seizures (allow for safety under these circumstances)
- resident would stand on a platform (off the ground) – this would allow the standing table to be moved with the resident in it (caster wheels)
- make sure to support the entire body
- have a knob that allows the standing table to move up and down
- eliminate aide’s need to have their hands on the resident (no skin contact), hand over hand assistance
- sling – harness (supports lower body) – adjustable straps
- knees might not totally straighten (need to be supported so the resident would be comfortable in this case)
- legs of standing table could be made closer to the ground (than that of Hoyer lift) – this would allow the standing table to pull up close enough to an easy chair that it would be able to fit underneath the chair and the standing table would be able to be used for chairs other than the resident’s wheelchair – low clearance
- caster wheels under the standing table would be able to be locked into place so that the standing table is secure when in use
- table top must be clear so the resident would be able to see their feet and the ground in front of them, should the standing table be moved
- table top should be able to be tilted to 20 - 30º tilt from horizontal
- table top should have guard around bottom (especially if table tilt is involved) so that nothing falls off the table top and should be weight bearing and be used for table top activites
- resident should be able to go from sitting to standing in 45 – 60 seconds
- this standing table will be used in a residential atmosphere that doesn’t currently have standing tables (not in that house, but some do have them)
- there should be a remote to activate the actuators – this remote should be out of the range of motion of the resident
- rechargeable battery would be used so that the Arc wouldn’t have to keep buying batteries – the battery should be out of sight
- the maximum height of the standing table itself should be around 6 feet, but ideally it would be more in the range of 4 to 5 feet – the standing table should also be able to move through doorways, so should be less than 3 feet in width
Section 3 – Design Parameters
- voltage and battery capabilities
- time to set up the standing table and put it away
- time to transfer the resident
- amount of power used
- number of operations required
- weight limit of the standing table and overall size
- amount of discomfort caused and injuries resulting from use of this standing table – this would be minimized
- colors available
- materials used
- type of actuator
- harness system
- number of parts
- adjustability
- number of pads
- number of safety precautions
Section 4 – Objective Trees
Objective Trees, Organized by Performance, Cost, Safety, and Comfort
[pic]
[pic]
[pic]
[pic]
[pic]
Section 5 – Morphological Charts
Morphological Charts Detailing Exclusive and Non-Exclusive Concepts
[pic]
[pic]
Section 6 – Individual Concepts
Chart Detailing a Selection of Individual Concepts
[pic]
Section 7 – Team Preliminary Concepts
[pic]
Section 8 – Final Morphological Chart
[pic]
Section 9 – Final Concepts
Chart Detailing Final Concepts for the Weighted Pugh Analysis
[pic]
Appendix I – Pneumatic Fluid Drives
Section 1 – Solid Model: “Extend” Drive Cylinder
[pic]
Solid Model Detail of “Extend” Drive Cylinder
Section 2 – Solid Model: Fluid Drive/Leg Interface
[pic]
Solid Model Detail of Fluid Drive/Leg Interface
[pic]
FEA Analysis of Leg
[pic]
Front View of Base Deflection While Lifting a 300lb Person
Section 3 – Fluid Drive Ratio Formulas
Determination of Fluid Drive Ratio Formulas
Use of liquid ( No compression of fluid ( Maximum [pic]rate
Input :
[pic]r1 F1
dx P1
Output:
r2 F2
dy P2
[pic]
[pic](1) [pic] [pic] Pressure @1=[pic]
(2) [pic] [pic] Force @2= [pic]
Note: If output is larger less force is needed.
[pic] (1) [pic]
(2) [pic] [pic]
Note: If input is larger, output distance is decreased.
[pic]F2 = [pic]
[pic]dy = [pic]
Section 4 – Force and Travel Ratios for Cylinder Bore
Force and Travel Ratios for Given Cylinder Bore Ratios
[pic]
Section 5 – Fluid Drive Schematic
Fluid Drive Schematic showing input cylinders at left, leg cylinders at right
[pic]
Section 6 – FEA Analysis of Drive Cylinder Assembly
[pic]
FEA Analysis of Drive Cylinder Assembly, 200 lb load
Section 7 – Stress Lift Curves of Base Assembly
|Part Name |Max Stress (ksi) |Min Stress |
|Total Travel |8 |in |
|Needed Travel |6.5 |in |
|Time To Travel |14 |secs |
[pic]
Section 10 – Free Body Diagram of Lift Arms
500lb
Section 11 – FEA Analysis of Lifting Arm
[pic]
Front View of Lift Arm Deflection While Lifting a 300lb Person
[pic]
Side View of Lift Arm Deflection While Lifting a 300lb Person
Section 12 – Pin Shear Calculations
[pic]
[pic]Actuator pins:
There are two pins with a force of 500 lb each which will be used to connect the actuator to the frame and the other connecting the actuator to the lift arm. The pins are in double shear.
[pic]
The total force for both pins is 2546.4 psi.
There is also a pin located on the actuator arm. This pin is also in double shear. There is a 445 lb force acting on that pin.
[pic]
There will never be more than a 500lb force on the actuator.
Both of these values are below the manufacturer recommend of 84,000 psi
Section 13 – Stress Life Curves for Lifting Assembly
|Part Name |Max Stress (ksi) |
|Amp Hour |26 |
|CCA* |--- |
|Length |6.5" |
|Width |6.86" |
|Height |4.94" |
|Weight |18.05 lbs |
Battery Charger
The charger for the battery being used is a 71708 battery charger and is commonly used for sealed lead-acid batteries, which is being used for the system. The features of the charger are as follows:
• 3-Stage Switch Mode
• Maintains 12 V lead-acid batteries
• Fast charge, topping charge and float charge states
• Short circuit protection system protects the battery from short circuit damage
• Over-voltage protection protects the battery being charged from damage
• Charger offers reverse polarity protection capability, rendering the charger and battery safe against any incorrectly connected cables
• Multi-color LED display to indicate the charging status
• Engineered for safe automatic charging
• Maintains a full charge
• Built to last
• Compact, very light and extremely powerful
The specifications of the battery are as follows:
• Input Voltage: 100-120 Vac
• Input Frequency: 47-63Hz
• Output Voltage Fast Charge (Bulk): DC14.4V
• Float DC: 13.6V
• Output Current Fast Charge (Bulk): DC 2,000mA
• Battery Capacity: 5-100Ahr (Suggested)
• Operation Temperature: +32°F/0°C to +104°F/40°C
• Storage Temperature: -4°/-20°C to +140°F 60°C
Source:
Thus, with this charger, the battery used in our project would take about 6 hours to charge as our battery is of 26 Amp capacities. Therefore, 26A-h/4A = 6.2 hours. Thus, the recharging capacity of this battery is 4 times faster than the charger currently used at the Arc. That battery takes approximately 24 hours as it was discovered during the meeting with our client. Thus, this charger is in every way superior to one currently used at the Arc.
Section 3 – Wiring Diagram for Circuit
[pic]
Appendix L – Force Determination for Caster (Beam)
F = 200lb
L=35.5 in
a=30.5 in
b=5 in
[pic]
Max. Stress and Moment:
V(x)
lbf
M(x)
lbf-in
These figures indicate that the max stress and max moment occur in the beam at the point of application of the force.
[pic]
Caster Plate While Lifting a 300lbs. Person
[pic]
Caster Legs While Lifting a 300lbs. Person
[pic]
Appendix M – Force in Main & Secondary Support
[pic]
[pic]
The total stress on the beam:
[pic]
[pic]
[pic]
Main Support While Lifting a 300lbs. Person
[pic]
Main Support While Lifting a 300lbs. Person
Appendix N – Stress in Table & Bolt
Stress on Table and Bolt
The stress on the table when the user is leaning against the chest pad (assuming the user is leaning forward 5 degrees, and weighs 300 pounds).
[pic]
Pins in shear:
The pins that are used to interface the main and secondary support are in shear.
[pic]
The shear on the pins is less than the manufacture specified maximum of 42,600 psi.
Appendix O – Bill of Materials (BOM)
[pic]
[pic]
ACTUAL TOTAL = $1,717.60
ADJUSTED TOTAL = $1,453.50
Appendix P – Assembly Plans
The basic manufacturing of the parts is going to be done using a TIG weld. It provides superior quality welds and can be made with or without filler material. Parts are going to be manufactured in the Mechanical Engineering Machine shop in the engineering building at RIT. Extensive use of milling and lathing of parts is going to be done to obtain the design.
For the electrical part of the project, the circuits and connections are to be made using thru-hole technologies in which the pins designed are inserted into holes and soldered to pads on boards. This would be done in the electrical engineering laboratories and the Mechanical Engineering Machines shop as done for welding. Once the actuators reach, the batteries would be connected to it to the working of the actuators.
Ergonomics parts assembly
The wooden board for the foot plate will be cut across the length of the board so that there will be one larger length piece and two smaller ones. Smaller holes will be drilled closer to one end of the wooden board in order to allow for securing of caster wheels for support, as seen in the drawing. There will also be some larger holes on the other end of the wooden board to allow for brackets to be connected in order to attach the entire foot plate assembly to the main frame of the standing table itself. The two smaller pieces will then be positioned on top of one another at one end of the larger board, and nails will be used to hold them together. A series of bolts and nuts will then be used to line up and attach the two caster wheels underneath the wooden board. Brackets will then be attached to each other and welded to the main frame, and the wooden board will be attached to these brackets. Anti-fatigue material will be attached to the wooden board after everything else is put together to cover the heads of the bolts used for securing the wooden board, and this will also provide comfort and a non-slip surface for people using the standing table.
The knee pad will be created by cutting two small pieces of metal extrusion to spec and welding them directly to the main two posts of the standing table, with a longer piece connecting the smaller two pieces. The wooden board will be cut and drilled as called for in the drawing and high density foam will be attached to the wooden board using glue specially made for this type of application. These materials will then be covered with the soft vinyl material and stapled to the back of the wooden board. This board will then be connected to the metal frame, which will provide a great deal of comfort and support for the person being lifted in the standing table, which is of particular importance, given that the main pivot point of the person will be about their knees in the knee pad as they are being lifted.
The chest pad will consist of a wooden board for support that will be attached with brackets to the T-slot material that will form a frame to hold the table top material in place. The wooden board for this pad will be shorter than the length of the foam connected to it, which will be used in the knee pad, because with the tilting table top, the chest pad will be leaned towards the individual using the standing table. This is the reason for the curved design of the foam, which allows for more contact once the table is tilted. The high density foam for this part will be cut and formed in a way to provide extra support. This part will also be covered in the soft vinyl material.
The harness will be made up of nylon webbing sewn together as shown in the drawing with Kevlar thread. Thick batting will be attached for added cushion, along with the low-density polyethylene material for back support. More pieces of the nylon webbing will be attached at each end of the harness and sewn together with metal rings at different lengths. These rings will be attached to the lifting arm, and the different lengths between the rings will allow for different amounts of tension in the harness, depending on the size of the person and how they are positioned. Finally, the harness materials will be covered with a soft fabric for comfort.
Appendix Q – Business Plan Outline: Standing Table
“It is the ability, not the disability of the person that counts.” - Unknown
It is rarely thought of how the ability to stand affects people and their lives. Standing gives a greater access to various social, vocational and recreational activities. There are many people in the world who are unable to stand by themselves or need aid to do so. Thus there are many devices which act as standing aids, and the standing table is one such device.
The main plan, or goal, of Senior Design Team P06205 is to design a standing table for the Arc of Monroe County. The project is to be finished by the end of spring quarter of 2005-2006 at RIT. After building the standing table, the team will test it thoroughly. Consideration is being made that the final product may be copyrighted and sold by the team or an organization with authorization from the team.
Thus, the team has decided to make a business marketing plan for the standing table which can be used after the standing table is built so that it can be marketed and sold. The design which has been decided upon for the standing table is a state of the art design, appears to be comparably priced as compared with other standing tables offered now in the market. Additionally, it abides with all rules and regulations and contains all the required safety features.
Presently, the standing table is in the design phase. The complete business plan is to be made in the second half of the senior design course, but a basic overview of the standing table market is going to be discussed now.
OVERALL MARKET
During research, it has been found that approximately 20 million Americans, approximately 10% of the population of the United States, has some disability related to legs and thus, become our target market. This group has about $80 billion in discretionary income.
This is a very vast number and is approximately equal to the spending power of American teenagers and several times (about 8) the spending power of the American “tweens” market. Thus, the market is huge and there is a lot of profit potentially involved in it. However, this market has not yet been fully tapped into.
The options and advantages of accessibility attract not only those people with disabilities, but also their family and friends. Disabled people often visit stores, go to restaurants and movie theaters accompanied by their family and friends. This desire for travel expands the market by a great amount.
The market is certainly growing at a high rate. By 2030, 71.5 million Baby Boomers would be over the age of 65, out of which it can be predicted that about 30 million would be demanding products and services which address their age related physical changes.
A point to be thought of before making any business plan, is that everyone benefits when businesses give customers with disability an equal opportunity to obtain their goods and services. By considering this, businesses can make it easier for people with disabilities, as well as other customers, to access and purchase the services or products they have to offer. Accessibility pays dividends and makes good business sense.
OUR BUSINESS PLAN: OUTLINE
The team will create a marketing plan for the standing table targeting both general and internet aspects of the market. The plan will include a budget proposal as well as a number of strategies to make this product in the evoked set of consumers, and therefore sell. The online website development for the team is currently in stage 0 meaning that the team does not have a website domain name, and is not on the internet. The internet offers a huge opportunity for business which can be exploited. One marketing objective is to reach stage 2 of business online development, meaning that a website will be created along with slight developments including information and pictures. Additionally, there will be content with a basic e-commerce facility for online transactions.
To determine the best course of action, the team is considering the four Ps of its marketing mix: Product, Price, Placement and Promotion to understand the strengths and weakness of the team. Due to limitations of resources and time, the marketing plan for the product would focus primarily on the aspect of promotion and its online functionality – that is, the team desires create an online presence for the product being marketed. However, if time permits, the marketing plan can also focus on various integrated marketing communication strategies.
The basic resources and opportunities which the team can take advantage of after reaching stage 1 of online business development include portal usage, online transactions, partnerships, improved trust measures, metrics gathering, legal considerations, advertising strategy, and search engine strategy to name a few. Regardless of the team’s success, capital is always a limiting constraint on growth, and Senior Design Team 6205 is absolutely no exception.
The team management would make informed decisions about which strategy would work best for immediate and long term implementation for the team’s marketing activities based on the costs. For each option presented, there will be methods of measuring usefulness included. Overall, significant developments have been made by the team in designing the product and thus the team is taking a different viewpoint with the project by giving it a business perspective. This could not only help the team, but also, RIT and the Arc.
MARKETING MANAGEMENT PROCESS
There are five questions which correspond with the analysis, planning, implementation and control of the process of marketing management. These questions form a logical framework for potential development into distinct and easily identifiable portions based upon levels of implementation.
The questions are as follows:
Where are we now?
Currently, the team is in the design stage of the product and the project will finish at the end of the spring quarter 2005-2006 at RIT. Currently, there is no marketing structure, as the product is in the design phase, and finishing the product has been given top priority. The team currently has a basic idea of how they are going to go about production, and has an outline of the business plan.
Where do we want to be?
The main project objective is to have a thoroughly tested standing table along with a website in the stage 2 process of online business development. Although starting a formal business is not an objective of the team, this gives them the advantage of understanding how business operations run, and can be extremely useful if they wish to pursue it in the future. Thus, a platform to reach stage 3 of online business development is another objective for the team. Stage 3 means that the website would have significant developments in it. There is a high degree of interactivity and features like e-commerce are present. The website has an active online presence.
How do we get there?
An appropriate use of the marketing mix consisting of 4 P’s is the answer to this question. The 4 P’s of marketing are product, price, placement and promotion. Analysis of each will give the team a background of the marketing infrastructure to be built.
How to ensure safe arrival?
For each marketing strategy which is presented, there will be a number of ways to measure usefulness such that, with these measures in place, the team can discontinue those strategies or services which appear to be unprofitable.
E-STRATEGY
The basic online strategy is to take a completely offline presence online, and then from a passive to an active online presence. The goals of the e-strategy are to achieve the following:
• Make the design a clear option for our target market and the product in their evoked set.
• Make consistent use of online technology and e-commerce.
• Become a preferred destination for information regarding standing table and news regarding standing table builds, and maintain a decent public relations standing.
• Progress is making it well established through knowledge that our clientele can expect superior services from the team.
• Provide online and offline services to customers before, during and after the transactions have been completed.
BASIC MARKETING MODELS
Porter’s five forces is a marketing model which is used by various businesses to understand their core competencies and competition, and to aid them in understanding the industry in which they operate. The five forces are supplier power, barriers to entry, threat of substitutes, buying capacity and degree of rivalry. These are also known as potential entrants, buyers, industry competitors, suppliers and substitutes.
[pic]
Source: brs-
Suppliers
The product will be fairly dependent upon suppliers. Presently, there is no need for any personnel but, depending on the team’s progress, there may be in the future. Some of the supplies needed are actuators, batteries, switches, metals, foam, and casters. A list of the project’s supplies is given in Appendix O. The suppliers are present in abundance on the internet, and it is certainly not hard to find parts. Once, a relationship with the supplier is established, it is possible to get reduced prices which can considerably decrease overall costs. Since, the product is in the design stage, the overall cost of the product can only be estimated but seems fairly reasonable.
Barriers to Entry
There are a number of other companies and organizations offering standing tables, but many of them are expensive with a lack of features and automation. The team’s design appears to be simple, powerful and comparatively inexpensive for the capabilities of the table. The risk of having new competitors in this region is not very high.
Threat of Substitutes
A substitute product in the market can always pose a threat. Although competitors cannot fully replicate the design, it is possible for them to get very close. It is necessary to research competitors and understand their designs to create product differentiation and a distinct market positioning.
Buyer Power
Buyers and consumers have the ability to go anywhere on the internet and the market Thus, it is important to make sure that online business development is growing at an efficient rate and that the team is always available to our potential customers.
Degree of Rivalry
There are a number of competitors, but as discussed earlier, the key is in product differentiation, image differentiation and market positioning. Public relations strategies can be adopted to maintain competence in the market. Once the product is in the building process, during the second phase of this project, discussions of strengths and weaknesses with respect to our competitors will be done – an analysis of this immediately opens doors to a number of marketing strategies.
Another marketing model which is going to be used is the Mckinsey 7-S framework. This framework is a heuristic which determines the internal workings of an organization. Organizational culture is formed of seven interacting variables: systems, style, structure, shared values, skills and strategy.
[pic]
Source:
A brief description of these terms is given in the following page.
The 3Ss across the top of the model are described as 'Hard Ss':
Strategy: This direction and scope of the company over a certain decided period of time.
The current business strategy for the company does not exist because the product is in its design stage.
Structure: The basic organization of the company, its departments, reporting lines, areas of expertise, and responsibility (and how they inter-relate).
This is a student managed team, the organizational structure of which is given in Section 4 of the report.
Systems: Formal and informal procedures that govern everyday activity, covering everything from management information systems, through to the systems at the point of contact with the customer.
The team does not have a comprehensive understanding of the clientele’s buying behavior in marketing terms, but the product attributes are specific to the ARC’s specifications. Thus, the product is being designed according to the client’s specific requirements which gives the team a great opportunity to market on the basis of product differentiation. This also promotes the thought of creating direct marketing strategies.
The 4Ss across the bottom of the model are less tangible, more cultural in nature, and were termed 'Soft Ss' by McKinsey:
Skills: The capabilities and competencies that exist within the company, or what it does best.
Since the team is a student design team, the learning curve is high and the product can be constantly improved. The present team has core competency in engineering and thus, the skills of the team can be considered to be high.
Shared values: The values and beliefs of the company. They ultimately guide employees toward 'valued' behavior.
All of the product standards are maintained, and the ADA regulations have been met. The assumption is that once the business is started, quality of service and customer satisfaction would be given a very high priority just as the client’s requirements have been given right now.
Staff: The company's people and resources, and how they are developed, trained, and motivated. Currently the staff includes only the team.
Style: The leadership approach of top management and the company's overall operating approach. The organizational structure is minimal, but there is a fair amount of cooperation within the team making it easy to get work done.
SUMMARY
If implemented after the end of this business proposal, many organizations can take advantage of the team’s marketing strategy. The team, RIT and the ARC of Monroe County are all potential benefidiaries. A small non-profit enterprise could be created which can be used extensively for fund raising activities, etc. This busniness could also become a professional enterprise with some more managing capabilities. This would be a small-scale industry, and would definitely be for a good cause as described in the beginning of this section. The previous proposal is just an outline, with the main objective for the inclusion of this section to analyze the marketing environment the team operates in. The complete recommendations in the areas of strategic planning, strategy formulation, and strategic evaluation will be given following the completion of the product.
An overview of the business plan for Senior Design II deals with the discussion of a number of business aspects. Some of them include redefining the target market, competitor analysis, integrated marketing communication strategies, advertising, online trust, implementation strategies, etc.
References:
The Americans with Disability Acts Publication.
Fact Sheet on Standing aids by
US Department of Labor:
Appendix R – Engineering Drawings
Drawing No. Part Name
1. ¼-20 x .5” BHCS
2. ¼-20x1”LHSHCS
3. .3125-18 Bolt
4. .3125-18x.625 BHSC
5. Quick Release Pin
6. Weld Pin
7. Lock Caster
8. 2426T52 Caster
9. 8020-4302
10. 8020-4024
11. Caster/Leg Assembly
12. 8020 Table
13. Cap for Pivot Point
14. 8020 Leg Adapter
15. Caster Mounting Table
16. Caster Leg 2
17. Caster Legs
18. Main Support Leg
19. Secondary Support
20. Lexan table top
21. .3125x.25 Shoulder bolt
22. Universal Power Battery
23. Battery Tray
24. Actuator Bushing
25. Bottom Bracket Drive Cyl
26. Foot Plate-Wooden Base
27. Duff Norton Actuator
28. Bearing Bolt
29. Chest Pad-Corner Brace
30. Tslot Bearing
31. Push Cylinder Bracket
32. Chest Pad- HD Foam
33. Chest Pad-Wooden Base
34. Nylon Inset Lock Nut
35. Cylinder Mounting Nut
36. Knee Pad-Frame Arm
37. 1.5” Shoulder Bolt
38. Base
39. Knee Pad-Frame Main Beam
40. 1.75” Shoulder Bolt
41. Actuator Bracket
42. Knee Pad-HD Foam
43. Knee Pad-Wooden Base
44. 2” Bore Bimba Cylinder
45. 1-1/6” Bore Bimba Cyl
46. Quick Connect Fitting 3/8”
47. Quick Connect Fitting 3/8”
48. Arm Bracket
49. Knee Pad-Corner Brace
50. Harness-LDPE Backing
51. Foot plate: anti-fatigue mtrl
52. Final Assembly
53. Foot plate-caster
54. Foot Plate-Corner Brace
55. #10-32 1-1/4” Bolt
56. 5/16”-18 x 1-1/2” Bolt
57. 5/16”-18 x 7/8” Bolt
58. 3/8”-24 x 2-1/2” Bolt
59. 3/8”-24 x 1-3/4” Bolt
60. ¼”-20 x 3/8” Bolt
61. #10-32 x 1/8” nut
62. 5/16”-18x½”x17/64” Hex Nut
63. 3/8”-24 x 9/16” x 21/64” Hex Nut
64. 3/8” ID, 7/8” OD washer
65. 15/32” ID, 59/64” OD washers
66. Arm Bushing
67. Lift Arm
68. Fluid Drive Tube
-----------------------
ACTUATOR & CYLINDERS
Craig
ELECTRICAL
Aditya
POWER
Aditya and Craig
FRAME
Kahamala and Matt
BIOMECHANICS/
ERGONOMICS
Jeff and Maria
STANDING TABLE
Aditya Srinivas
(Co-Lead Engineer)
EE
Maria Spagnola
(Co-Lead Engineer)
ME
Kahamala Morgan
(Budget)
ME
Jeff Matusik
(Meeting Minutes)
IE
Matthew Bell
(Report Organizer)
ME
Craig Hudson
(Team Manager)
ME
y
L
F
b
a
x
B
M3
R2
R1
5472 lb-in
478.75lb-in
3725 lb-in
A
M1
500 lb
383 lb
R2
R1
228 lb
40lb
10 lb
Design Standing Table for ARC Monroe County
Performance
Cost
Safety
Comfort/
Aesthetics
Performance
Efficient
Adaptable for different people
Lift Large Patients
Compact Design
Easy to Use
Low profile
Stand alone
Foldable/
Collapsible
Low drain
Minimized number of steps required
Adjustable
Sturdy and stable
Powered actuator
Automated
Intuitive user interface
One person use
Cost
Low
Operating Costs
Low
Maintenance Cost
Cheaper than existing designs
Low cost parts
Remanufacture
Donations/ price red
Minimal power consumption
Avoid non-renewable power sources
Durable
Samples
OEM subsystems
Standards
Readily available
Materials and processes
Powered systems scaled to use to avoid over design
Replacement parts easy to obtain and install
Minimal preventative maintenance required
Safety
Automatic safety stops/kill switch
Stable during operation
Minimal maintenance design
No sharp edges
Easy to maintain
Eliminate service induced damage failures
Measure activity
Switches for emergency
Retractable platform support
Minimize profile
Utilize chamfers and breaks
Pad contact surfaces, frame corners, and protrusions
Lower center of gravity
Minimize 90o bends near patients
Aesthetics/
Comfort
Visually Appealing
Ergonomic Design
Pads
Supports
(Lateral, trunk, lower body)
Different color schemes available
Soothing colors
Enclose mechanical parts
Organic design
Minimize square edges
[pic]
F
[pic]
[pic]
L[pic]
[pic]
L
y
L
F
b
a
x
B
M3
R2
R1
y
-170.45
29.55
x
462.5
x
10 lb
228 lb
40lb
R1
R2
383 lb
500 lb
M1
A
3725 lb-in
478.75lb-in
5472 lb-in
................
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