Inversion tables do they work?

Home Gym with Inversion Table A Baccalaureate thesis submitted to
the School of Dynamic Systems College of Engineering and Applied Science University of Cincinnati in partial fulfillment of the requirements for the degree of Bachelor of Science in Mechanical Engineering Technology by Aaron Crum April 2013 Thesis Advisor: Professor Amir Salehpour

ii TABLE OF CONTENTS TABLE OF CONTENTS .......................................................................................................... II LIST
OF FIGURES ................................................................................................................ III LIST OF TABLES .................................................................................................................. III INTRODUCTION .................................................................................................................... 1 EXISTING PRODUCTS .......................................................................................................... 2 HOME GYM FITNESS EQUIPMENT ....................................................................................................................... 2 INVERSION TABLES ............................................................................................................................................. 4 SUMMARY .......................................................................................................................................................... 5 CUSTOMER FEEDBACK, FEATURES, AND OBJECTIVES ............................................. 6 INTERVIEWS ........................................................................................................................................................ 6 SURVEY ANALYSIS ............................................................................................................................................. 7 FEATURES AND OBJECTIVES ............................................................................................................................... 8 PROTOTYPE OBJECTIVES - QFD ............................................................................................................... 10 SCHEDULE AND BUDGET ................................................................................................. 11 SCHEDULE ........................................................................................................................................................ 11 BUDGET ............................................................................................................................................................ 12 3D SOLID MODELS OF THE TOTAL GYM ...................................................................... 14 DRAWINGS ........................................................................................................................................................ 14 LOADING CONDITIONS AND SAFETY FACTOR .................................................................................... 16 COMPONENT SELECTION .......................................................................................................................... 20 BILL OF MATERIALS .......................................................................................................... 21 EXPLODED VIEW ................................................................................................................ 22 FABRICATION ...................................................................................................................... 23 TESTING AND CONCLUSION ........................................................................................... 32 REFERENCES ....................................................................................................................... 33 APPENDIX A - RESEARCH ................................................................................................ A1 APPENDIX B – SURVEY .................................................................................................... A2 APPENDIX C – QUALITY FUNCTION DEPLOYMENT ANALYSIS ............................ A3 APPENDIX D – PRODUCT OBJECT IVES ....................................................................... A4 APPENDIX E – SCHEDULE ............................................................................................... A5 APPENDIX F – BUDGET .................................................................................................... A6 APPENDIX G – SHOP DRAWINGS ................................................................................... A7

iii LIST OF FIGURES Figure 1 - Bowflex Home Gym
................................................................................................ 2 Figure 2 - Total Home Gym...................................................................................................... 3 Figure 3 - Teeter Fitspine Inversion Table ............................................................................... 4 Figure 4 - IronMan LXT850 Inversion Table ........................................................................... 5 Figure 5 – 3D Model of Machine in Workout Position .......................................................... 14 Figure 6 - 3D Model of Machine in Inversion Table Position ................................................ 15 Figure 7 – Foot Plate Stress .................................................................................................... 16 Figure 8 – Full System Deflection .......................................................................................... 17 Figure 9 – Bending Stress in Rails .......................................................................................... 18 Figure 10 – Shear Stress of Rotational Pins............................................................................ 19 Figure 11 – Exploded View of Full Gym ............................................................................... 22 Figure 12 – Waterjetting Aluminum Rotational Plates ........................................................... 23 Figure 13 – Band Saw Cutting ................................................................................................ 24 Figure 14 – Upholstering The Backrest .................................................................................. 25 Figure 15 – Wheels Added onto Backrest .............................................................................. 26 Figure 16 – Welding Steel Brackets ....................................................................................... 26 Figure 17 – Creating T-brackets ............................................................................................. 27 Figure 18 – Foot Slider Assembly .......................................................................................... 28 Figure 19 – Footrest Assembly ............................................................................................... 28 Figure 20 – Frame Coming Together...................................................................................... 29 Figure 21 – Rotational Plate Assembly .................................................................................. 29 Figure 22 – Machine Fully Assembled ................................................................................... 30 LIST OF TABLES Table 1 - Survey of Important Features 7 Table 2 – QFD Analysis for Engineering Characteristics 10 Table 3 – Schedule 11 Table 4 – Budget 12 Table 5 - Final Budget 13

Home Gym with Inversion Table Aaron Crum 1 INTRODUCTION Home
gyms have been around for decades, with promises that just a few minutes a day can help turn the average couch potato into the next Sylvester Stalone. They come in all shapes and sizes from the simple Bullworker spring to complex home gyms systems such as the Bowflex. Before a workout begins, and after a workout ends, the best thing for your muscles is a good stretching. Stretching is important for people of all ages and skill levels. The benefits include increasing the range of motion, reduced muscle tension, and increased circulation to various parts of the body. Also, stretching after working out is beneficial workout recovery and decreases muscle soreness. One of the most useful stretching devices on the market today are inversion tables. These are machines that turn the user’s body upside-down, with their ankles supported by the table. The purpose of using this machine is to allow the user to stretch out after working out, and provide a method to decompress the spine. On the market today, there are hundreds of types of home gyms, as well as inversion tables for sale. The focus of this project is to design a machine that can both incorporate a home gym, and an inversion table into one unit.

Home Gym with Inversion Table Aaron Crum 2 EXISTING PRODUCTS
HOME GYM FITNESS EQUIPMENT There are many different types of home gyms, but they all perform a very similar task. They can be broken down into two categories. One contains some type of resistance band, or spring that gives resistance to a particular motion. The other utilizes gravity as resistance, whether it is a set of weights, or the user’s own body weight. When it comes to resistance bands, the most well-known home gym is the Bowflex, as shown in Figure 1 (1). The Bowflex requires the user to overcome the bending force of the resistance bands. The different bands on the back of the machine are rated at different weight capacities. The problems with these kind of machines are their price, as well as lack of ability to stretch using the machine. Initial investment cost is a very key factor in purchasing a home gym, and many of these gyms can cost thousands of dollars, turning many people away. Figure 1 - Bowflex Home Gym

Home Gym with Inversion Table Aaron Crum 3 Gravity-based workout
units are the predominant ones found in fitness centers. They typically consist of a stack of weights, a steel cable, and a few pulleys. The simplicity causes the machines to be durable and allows the user to track their progress by seeing exactly how much weight they are lifting. The downsides to these machines are their high cost, and size. Other examples of gravity-based workout units include free weights such as dumbbells, and products that involve the user lifting a percentage of their own body weight. These machines take up less space and are relatively inexpensive. The main complaint for these home gyms are that they lack versatility and the time it takes to adjust between workouts. An example of one of these systems is the Total Home Gym XLS as shown in Figure 2 (2). Figure 2 - Total Home Gym

Home Gym with Inversion Table Aaron Crum 4 INVERSION TABLES
While many people haven’t used an inversion table, most people are familiar with them through TV ads, and seeing similar devices in various gyms. Almost all of them work by strapping the user’s ankles to the lower part of the table and then flipping the user upside down to relax and let their muscles and spine stretch out. The most popular model on the market is the Teeter Fitspine, as shown in Figure 3 (3) is the most popular model on the market today. It is a very basic no-frills device that allows the user to strap their feet and ankles in and flip upside-down. As with most exercise equipment, the price always tends to be an issue. This model is over $400, while others by the same company can cost upwards of $900. For a device that only serves one purpose, many people think the cost outweighs the benefits. Also for this particular model, there is no locking mechanism to keep someone in place. This could be an issue causing the user to rock back and forth in the machine. Figure 3 - Teeter Fitspine Inversion Table

Home Gym with Inversion Table Aaron Crum 5 The IronMan
LXT850 as shown in Figure 4 (4) overcomes most of the bad qualities of the Teeter device. It has a lower cost at a sub-$300 price point, and has a locking mechanism that can hold it into 10 different positions. Figure 4 - IronMan LXT850 Inversion Table SUMMARY There is a gap in the market where working out, and stretching is combined into one single unit. The goal of this project is to fill this gap with a machine that can be used to have a full- body workout, and then quickly turn into an inversion table to stretch out with.

Home Gym with Inversion Table Aaron Crum 6 CUSTOMER FEEDBACK,
FEATURES, AND OBJECTIVES INTERVIEWS Interviews were conducted with people that have a close relationship with the world of fitness and home gyms. The interviews were conducted to find out what kind of qualities are liked and disliked with home gyms and/or inversion tables. In an interview with Katy Brian, she explains how she liked and disliked her Total Home Gym (5). She explained how she has used the machine for over 5 years and has enjoyed it very much. Also, that it was a much cheaper and more convenient solution to working out than a gym membership. Jayme Johnson is the Coordinator of Facilities for the University of Cincinnati Recreation Center (6). As a Rec Center Coordinator, he is familiar with the hundreds of pieces of gym equipment, and has finished his Master’s Degree in the field of Exercise Science. He typically does not enjoy home gyms, and prefers to go to fitness centers for a few reasons. First, there is typically a larger variety of exercises that can be performed due to many different machines. Secondly, changing from one type of workout to another is as simple as switching machines. Finally, he believes home gyms are prone to breaking, and are not of the same quality as equipment found in fitness centers. In an interview with Christos Sampanis, he gave similar points as the previous interviewees (7). He says that the costs of home gyms are too much and he would prefer to pay a lower monthly fee rather than huge upfront costs. He also prefers fitness centers due to the wide variety in machines. On the other hand, he also enjoys a few aspects of home gyms. These include the privacy of working out at home, as well as not having to drive somewhere to workout.

Home Gym with Inversion Table Aaron Crum 7 SURVEY ANALYSIS
Fourteen surveys were handed out to people within the UC Rec Center to provide feedback from people who regularly workout. The survey listed a range of product features with which they were to give a 1-5 rating based on their importance (1 being least important – 5 being most important). The first section of the survey was to get information on what aspects of the machine are most important to them. The second was to find out what their opinions were on home gyms they have previously used (detailed survey results can be found in Appendix B). The results of the survey, along with the designer improvement plan can be seen in Table 1. The average customer importance column shows the survey results. The following columns show the expected improvement upon each of these qualities. The price has the second highest improvement ratio as this is the highest importance factor when considering the purchase of a home gym. This information shown is crucial in coming up with specific engineering requirements and finding ways to achieve high customer satisfaction. Table 1 - Survey of Important Features Questions Avg Customer Importance Designer's Multiplier Current Satisfaction Planned Satisfaction Improvement Ratio Modified Importance Relative Weight % Price 4.14 1.10 2.73 3.50 1.28 5.84 13.00 Capacity for varied user height/weight 3.71 1.00 3.23 3.50 1.08 4.02 9.00 Ease of operation 4.36 1.10 3.46 4.00 1.16 5.54 13.00 Ease of assembly 3.43 1.00 2.70 3.00 1.07 3.68 8.00 Quiet operation 2.92 1.00 3.69 4.00 1.08 3.17 7.00 Comfort 3.43 1.10 3.38 3.50 1.04 3.91 9.00 Stability 4.57 1.10 4.00 4.00 1.00 5.03 11.00 Small footprint 2.93 1.00 3.17 4.00 1.26 3.68 8.00 Safety 4.07 1.00 3.77 4.50 1.19 4.89 11.00 Ease of maintenance 3.64 1.00 3.15 3.50 1.11 4.04 9.00 Importance of Features of a Home Gym

Home Gym with Inversion Table Aaron Crum 8 FEATURES AND
OBJECTIVES The product objectives are the same as the list of customer features. In this section, these features have been listed in order of importance, along with their relative weight percentages. Also, under each one there are a number of objectives for how the prototype of this machine can fulfill the customer’s needs. 1. Cost (13%) a. Prototype under $500 2. Ease of operation (13%) a. Adjustment between exercises requires ≤ 3 steps b. Adjusts from workout station to inversion table in ≤ 3 steps c. Mechanisms to help with inversion d. Inversion table can be locked in all angles from horizontal to vertical with one hand e. Allows user ability to work out all muscle groups without reconfiguration 3. Stability (11%) a. Symmetrical design b. Consistent loading conditions and design for CG at or below comparable machines c. Frame to be welded instead of fastened 4. Safety (11%) a. All corners covered with rubber bumpers b. Ankle supports to lock to prevent falling c. No pinch points d. Safety bars on side of machine 5. Capacity for varied user height/weight (9%) a. Adjustable positioning for heights between 5’0” – 6’6” b. Includes ankle supports for range of human ankles c. Material and design will be sized and selected based on a 3.0 safety factor 6. Ease of maintenance (9%) a. All steels are stainless or coated to prevent rust b. All bearings are sealed requiring no lubrication 7. Comfort (9%) a. Back rest is typical weight bench padding b. Ankle supports are adjustable and padded comparable to Teeter brand c. Handle grips will be ergonomic

Home Gym with Inversion Table Aaron Crum 9 8. Ease
of assembly (8%) a. Uses standard hardware b. Uses standard tools for assembly and teardown c. Unit has ≤ 10 parts that need assembling 9. Small footprint (8%) a. Product to take up no more than 6’x4’ floor space b. Foldable frame to take up no more than 3’x4’ floor space 10. Quiet operation (7%) a. Contains roller bearings for smooth movements b. Uses rubber feet to prevent floor noise and vibration

Home Gym with Inversion Table Aaron Crum 10 PROTOTYPE OBJECTIVES
- QFD The analysis in Table 2 shows how the engineering characteristics given at the top of the chart are going to be solutions to the customer requirements in the left-hand side of the chart. These have been weighted and compared to achieve a relative weight percentage that will dictate which of these engineering characteristics are the most important to the final design. Table 2 – QFD Analysis for Engineering Characteristics The left side of this table shows the customer features. The top and center of the table shows how engineering characteristics relate to these features. To the right of the body, we have importance weights to each feature determined by taking the average responses from the surveys. Also, there is a designer’s multiplier and a final relative weight percentage. Finally, we have a relative importance percentage at the very bottom row that shows which characteristics are most important to implement in the design. Ankle supports Coated or stainless steel Standard hardware Rubber corners and feet Standard tools used for assembly Handles Foldable frame Roller Bearings Back rest Symmetrical Design Customer importance Designer's Multiplier Current Satisfaction Planned Satisfaction Improvement ratio Modified Importance Relative weight Relative weight % Price 3 9 9 1 1 1 3 1 1 4.14 1.10 2.73 3.50 1.28 5.84 0.13 13% Ease of Operation 1 9 1 4.36 1.10 3.46 4.00 1.16 5.54 0.13 13% Stability 3 1 9 4.57 1.10 4.00 4.00 1.00 5.03 0.11 11% Safety 9 9 3 3 4.10 1.00 3.77 4.50 1.19 4.89 0.11 11% Comfort 9 1 9 3.43 1.10 3.38 3.50 1.04 3.91 0.09 9% Ease of Maintenance 9 1 9 3 3.64 1.00 3.15 3.50 1.11 4.04 0.09 9% Capacity for varied height/weight 9 3.71 1.00 3.23 3.50 1.08 4.02 0.09 9% Small footprint 9 2.92 1.00 3.17 4.00 1.26 3.68 0.08 8% Ease of assembly 9 9 1 3 3.43 1.00 2.80 3.00 1.07 3.68 0.08 8% Quiet operation 9 9 2.92 1.00 3.69 4.00 1.08 3.17 0.07 7% Abs. importance 3.16 2.38 2.05 1.79 1.72 1.69 1.52 1.28 1.27 1.03 17.9 37.0 0.84 0.84 Rel. importance 0.18 0.13 0.11 0.10 0.10 0.09 0.09 0.07 0.07 0.06 1.0 Rel. importance % 18% 13% 11% 10% 10% 9% 9% 7% 7% 6% 100% Aaron Crum Home Gym with Inversion Table 9 = Strong 3 = Moderate 1 = Weak

Home Gym with Inversion Table Aaron Crum 11 SCHEDULE AND
BUDGET SCHEDULE The project time-table can be seen in Table 3. The concept development marks the beginning of the design phase of this project beginning in October. The design phase continues up till the end of December. Upon the start of spring semester, the fabrication phase will begin. This will run up till through March, with another month of tweaking and customer testing. Table 3 – Schedule

Home Gym with Inversion Table Aaron Crum 12 BUDGET An
initial budget of expenses is included in Table 4. This does not take into account machining and tooling costs. Prices based on internet quotes as of October 18, 2012. Table 4 – Budget Frame 40’ Tube steel ($2/ft.) $80 10’ Channel steel ($2.1/ft.) $21 Rolling Backrest Bearings $13 Wheels $19 Sheet of plywood $11 Shoulder bolts ($2.5/ea.) $10 Vinyl sheeting ($11/yd^2) $22 Foam padding $25 Inversion Table Pivot Joint and Handles Bar steel ($2.90/ft.) $3 Tube steel ($2/ft.) $8 Resistance System Handles $13 Resistance band set $20 Pulleys ($11/ea.) $22 Steel cable ($1/ft.) $10 Subtotal $277 20% Miscellaneous expenses $55 Total $333 Budget

Home Gym with Inversion Table Aaron Crum 13 Table 5
- Final Budget Final Budget Frame 2" Square tubing $130 2.5" Square tubing $75 2"x2" Angle Steel $30 Aluminum Sheet $25 Steel Rod $5 Rolling Backrest Trucks/Wheel Assembly $40 Wood $25 Vinyl Sheeting $20 Foam Padding $8 Resistance System Handles $20 Pulleys $30 Steel Cable $12 Cable Clamps $4 Carabiners $15 Foam Padding $20 Hardware Nuts, Bolts, Washers, Clips $15 Casters and Feet $30 Total $504 The cost ran over the planned budget. There were parts that were unanticipated, and the cost of the metals changed based off the vendor used. These parts were purchased based on what could be readily found, thus altering the original design slightly and increasing overall costs.

Home Gym with Inversion Table Aaron Crum 14 3D SOLID
MODELS OF THE TOTAL GYM DRAWINGS A full 3D model was created to see ensure all pieces will fit together properly. The rendering below in Figure 5 shows the machine as it is setup for working out. This position allows the user to work out against their own body weight by laying on the backrest and pulling themselves upwards (pulley cables and handles not shown). Figure 5 – 3D Model of Machine in Workout Position

Home Gym with Inversion Table Aaron Crum 15 The rendering
below in Figure 5 shows the machine as it is setup for use as an inversion table. This position allows the user to be suspended upside down by their ankles. Due to a locking mechanism, they can stay in this position until they are ready to rotate back to standing position. Figure 6 - 3D Model of Machine in Inversion Table Position

Home Gym with Inversion Table Aaron Crum 16 LOADING CONDITIONS
AND SAFETY FACTOR Most of the stress that this machine will see comes from the weight of the user in different positions. Points of high-stress have been analyzed to ensure there will not be failure. Since this machine will be holding a human above the ground, it is critical to ensure this machine will not fail and cause serious injury to the user. A maximum weight limit has been set at 300lbs, with a safety factor of two when calculating stresses. The following FEA calculations have shown that with 600lbs of force loading on critical points, there should be no mechanical issues. When stepping onto the machine to prepare for inversion, it is likely that the user will step on one side of the foot plate bar with their entire weight. Figure 7 shows the stress incurred in this subassembly if the user steps on the far edge. The force given for this calculation is 600lbs, which equates to ~36kpsi of stress on the joint edge. Because of a 90kpsi yield strength, this gives a total safety factor greater than 4. Figure 7 – Foot Plate Stress

Home Gym with Inversion Table Aaron Crum 17 The same
force has been applied in Figure 8 to check for deflection other parts of the system. This shows that most of the deflection will occur within the foot plate area. While the deflection is as important as the stress on the parts, it is important to include it because too much deflection will cause the user to think the machine is cheaply made. Figure 8 – Full System Deflection

Home Gym with Inversion Table Aaron Crum 18 Another stress
to be considered was the bending force occurred on the rails due to the user laying on the backrest. This is shown below in Figure 9. In this calculation, it has been assumed the four wheels will be in contact with the longest portion of channel aluminum for a worst case scenario and a 2.5 safety factor. This yields just under 5000 psi bending stress. This is significantly under the bending yield stress. Figure 9 – Bending Stress in Rails

Home Gym with Inversion Table Aaron Crum 19 Finally, hand
calculations have been done to show that a ½” steel bolt should be sufficient to support the shear stresses in the rotational joints. As shown in Figure 10, the pin will have a shear stress under 2300psi with 450 lbs of load. This is significantly under the 18000psi shear stress yield mark for 304 stainless steel. Figure 10 – Shear Stress of Rotational Pins

Home Gym with Inversion Table Aaron Crum 20 COMPONENT SELECTION
For the majority of this project, standard parts have been chosen to cut costs and ease procurement. Only a few parts, including casters, spring pins, and backrest rolling assembly are parts that need to be purchased and cannot be created from stock materials in the machine shop. All joints are designed to be fastened with standard bolt sizes that are readily available at any hardware store. The rails were originally chosen to be aluminum, but after a trial, this showed to be too malleable. Steel was then chosen. It turned out very well in terms of rigidity, and the ability to weld brackets onto it. Almost the entire rest of the assembly is composed of 2” square tube steel. It will have more than enough strength to support any kind of stresses this machine will incur. Secondly, it is readily available at many steel warehouse locations. Finally, this steel is easily machined, and weldable.

Home Gym with Inversion Table Aaron Crum 21 BILL OF
MATERIALS Bill of Materials Quantity Unit Description Material Vendor 426 in. 2" Square Tube Steel Metals Depot 180 in. 2" Channel Steel Metals Depot 1 pc. 20" x 20" x 1/4" Plate Steel Metals Depot 10 in. 1/2" Dia. Rod Steel Metals Depot 32 in. 2.5" Square Tube Steel Metals Depot 180 in. 3/16” Steel Wire Steel Home Depot 24 in. 3" Dia Tube Foam Amazon.com 1 pc. 48" x 20" x 3/4" Plywood Home Depot 1 pc. 100" x 20" Sheeting Vinyl Walmart 2 pc. Casters - McMaster Carr 6 pc. Adjustable Height Feet - McMaster Carr 4 pc. Pulleys - Grainger 1 pc. Spring Pin - J.W.Winco Inc. 1 pc. Longboard Wheel Assy - Amazon.com 1 pc. Nylon Strap Handles - Amazon.com 10 pc. 1/2" Dia Pins With Handles - National Gym Supply Inc.

Home Gym with Inversion Table Aaron Crum 22 EXPLODED VIEW
The following drawing shows the parts and assemblies in an exploded view. Also included is a list of part and assembly names that correspond with the bill of materials. Figure 11 – Exploded View of Full Gym

Home Gym with Inversion Table Aaron Crum 23 FABRICATION After
acquiring metals, and placing orders online through vendors such as McMaster Carr, and Grainger, the construction phase was started. The first pieces, the rotational plates were done at work with the use of a waterjet machine. The precision and tolerances needed to be CNC cut. Figure 12 – Waterjetting Aluminum Rotational Plates

Home Gym with Inversion Table Aaron Crum 24 The band-saw
was used to cut the tube steel down to size, as well as to put 45 degree angles on pieces. Figure 13 – Band Saw Cutting

Home Gym with Inversion Table Aaron Crum 25 Here, after
cutting the wood to size, the vinyl sheeting is being wrapped and stapled into the wood. Also, polyfil was stuffed inside to create a comfortable seat. Figure 14 – Upholstering The Backrest

Home Gym with Inversion Table Aaron Crum 26 Finally, longboard
trucks and wheels were attached to the backrest to have a finished product. The truck assemblies came with the wheels and bearings, so this process was fairly easy. Figure 15 – Wheels Added onto Backrest In the shop, pieces were getting welded together to later form the other assemblies. Figure 16 – Welding Steel Brackets

Home Gym with Inversion Table Aaron Crum 27 These two
T-joints were created for supporting the vertical posts. They were welded out of 2.5” square tube steel with a webbing thickness that allowed 2.0” steel to slide through easily. Figure 17 – Creating T-brackets

Home Gym with Inversion Table Aaron Crum 28 This piece
is part of the footrest assembly that will allow for change in leg thickness of the user. The pin will hold this slider in place. The following picture shows it on the footrest assembly. Figure 18 – Foot Slider Assembly Figure 19 – Footrest Assembly

Home Gym with Inversion Table Aaron Crum 29 The following
photo shows how all the bandsaw cuts are coming together to put the frame intact. Figure 20 – Frame Coming Together The rotational place assembly was then bolted on, causing two different parts to be able to rotate independantly of one-another. Figure 21 – Rotational Plate Assembly

Home Gym with Inversion Table Aaron Crum 30 After cutting
the foam for the footrest assembly, and adding cables, pulleys, and other hardware, the workout part of the machine is finished. Figure 22 – Machine Fully Assembled

Home Gym with Inversion Table Aaron Crum 31 The final
photo here shows the machine in an inverted position, although not fully 90 degrees vertical. This was just to show that the backrest was held in place, and that there was no issues with the machine in terms of usability.

Home Gym with Inversion Table Aaron Crum 32 TESTING AND
CONCLUSION The machine was tested under real-world conditions. Different people tried out the machine to check for any issues with the system. While the machine could be used as projected, there were parts that were difficult to use. The first issue was the rotational plates. While good on paper, these plates were very difficult to use in the real world. The issue here was that the pin that holds the two plates together absorbs all torque within the system. Because of this, the pin has a large amount of friction between the pin and the plates causing it to be very difficult to pull out when a user was on the machine. In fact, during testing of the inversion table, it was nearly impossible for the user to extract the pin while inverted. This was the most limiting factor in using the machine, and would call for a complete redesign of the rotational locking mechanism. Secondly, there was a metal-on-metal sliding joint that caused issues when raising and lowering the rails. The assembly consisted of a 2.5” section of tube sliding over a 2” section of tube. This was not a large problem, but it did get stuck on numerous occasions, even after grinding down any sharp edges. This would definitely be a hassle for the end user of the machine. Thirdly, since the machine was built with a modular design, everything was pinned or bolted together. This was good for assembling and disassembling the unit, but bad because it caused some slop where the bolt-holes weren’t perfectly aligned. Also, pinning everything into place was difficult for the user. In retrospect, it would have been a much better design to have a different locking mechanism than pins holding everything in place. Also, drilling very well-aligned holes for the pins to fit perfectly was very difficult on large pieces. In terms of manufacturability, the machine could be mass-produced very easily, requiring very few pieces of machinery. The prototype build was extremely over-built with the gauge of steel used, and further increasing the budget. If refined, this home gym could easily be produced at a priced point at or below $300. The modular design would allow the parts to be packaged into smaller boxes, and assembled at home. Finally, the entire machine could be assembled using just two common wrench sizes.

Home Gym with Inversion Table Aaron Crum 33 REFERENCES 1.
Nautilus Inc. Bowflex Xtreme 2 SE Home Gym. [Online] [Cited: September 2, 2012.] http://www.bowflexhomegyms.com/bowflex_home_gyms_us/products/xtreme2se/prdcdovr~ 100070/Bowflex+Xtreme+2+SE+Home+Gym.jsp. 2. IronMan. IronMan LXT850 Locking Inversion Table. Overstock.com. [Online] [Cited: September 2, 2012.] http://www.overstock.com/Sports-Toys/Ironman-LXT850-Locking- Inversion-System/3987541/product.html. 3. Total Gym. Total Gym XLS. [Online] [Cited: September 2, 2012.] http://www.totalgymdirect.com/total-gym-xls.php. 4. Teeter Hangups. FitSpine Trainer Inversion Table. [Online] [Cited: September 2, 2012.] http://www.teeter-inversion.com/Store/P-FS1002/Fitspine+Trainer+Inversiontable. 5. Brian, Katy. Interview with Total Home Gym owner. September 9, 2012. 6. Johnson, Jayme. Interview with Coordinator of Facility Operation at the UC Campus Rec Center. September 10, 2012. 7. Sampanis, Christos. Interview with Home Gym User. September 9, 2012.

Appendix A1 APPENDIX A - RESEARCH Interview with Total Home
Gym owner: Katy Bryan 307 Deer Chase Drive Duncan South Carolina 29334 09/09/12 She has owned the Total Home Gym for 5+ years, and uses it a few times per week. The ease of changing out accessories is a big plus, as well as the range of different workouts than can be done with one machine. She says the incline that the bench has does help for stretching, but the idea of an inversion table included would be very helpful. She has not heard of the idea to have a home gym and inversion table in one unit. Katy prefers using a home gym over going to a fitness center due to convenience, gym fees, and dealing with irritating people. Interview with Jayme Johnson: Coordinator of Facility Operations at the University of Cincinnati Campus Recreation Center. 2820 Bearcat Way PO Box 210017 Cincinnati, OH 45221 09/10/12 Background: Bachelors in Exercise Physiology, Masters in Exercise Science Jayme has used a variety of home exercise equipment, but prefers to go to fitness centers. His biggest complaint with a home gym is the time it takes to set up when going from one work-out to the next. For instance, he says “The time spent on changing resistances between workouts takes just as much time as the workout itself”. Secondly, he believes the quality of build on many home gyms is subpar, and they are prone to breaking. On the other hand, he praises home gyms on the variety of exercises that can be performed with one piece of equipment. He has used an inversion table for physical therapy, and thinks the idea of incorporating it into a workout machine is a wise idea. Besides the similarities of this and the Total Home Gym, he has not seen a similar product currently on the market. Interview with home gym user: Christos Sampanis 240 Greenup St. Covington, KY 41011 09/09/12 Christos has used many types of home gym equipment, including dumbbells, barbells, the Iron Gym, treadmills, and multiple types of benches. He says the downside of home gyms are cost, the total space it takes up, and lack of different exercises like are found in a fitness center. He enjoys having home gym equipment because it is more private, there is a lack of driving, and because he does not have to deal with the continued cost of fitness centers. He has not heard of a single piece of equipment that allows for both working out, and an inversion table but he would definitely be interested in trying out a machine like this.

Appendix A2 Bowflex Xtreme 2 SE Home Gym The Bowflex
Xtreme 2 SE is a Bowflex’s top selling home gym. It uses a series of “Power Rods” that act as different resistance levels to give the user approximately 70 different exercises from head to toe. The maximum resistance available for this home gym is 210lbs, but is expandable to 410lbs. The Bowflex works very well as a home gym, but does not provide the option of having an inversion table to stretch with after working out. Also, this home gym is very expensive at $1600 for this model. For more versatility in your workouts, the higher end models cost upwards of $3000. http://www.bowflexhom egyms.com/bowflex_ho me_gyms_us/products/x treme2se/prdcdovr~100 070/Bowflex+Xtreme+2 +SE+Home+Gym.jsp 09/02/2012

Appendix A3 Total Gym XLS The Total Gym XLS is
the top model from the Total Gym line. The resistance is based off the user’s weight. The incline of the bench can provide resistances from 6% to 50% of the user’s body weight. The company claims that the XLS model can provide 80 different exercises. The Total Gym workout system has been around for many years with very little change. As with the Bowflex, this does not include an option to turn it into an inversion table. This higher model is very costly at about $1000. Also, the range of resistance is very limited to the weight of the user. http://www.totalgymdire ct.com/total-gym- xls.php 09/02/2012

Appendix A4 Teeter FitSpine Inversion Table The Teeter FitSpine Inversion
Table is the #1 rated inversion table on the market today. This model includes adjustable ankle support for any size foot. It also has a strap to control the maximum angle of rotation. Features:  Pre-set rotation control  Smooth and Quiet rotation  Easy Assembly  Foldable for storage  Customizable accessories  Weight limit of 300lbs  Height capacity of 4’8” – 6’6” The Teeter FitSpine, as with many other inversion tables does not have a locking mechanism to lock into a specific angle. This model is $429, but others range from $289 - $999. The only exercises than can be performed on this product are abdominal. http://www.teeter- inversion.com/Store/P- FS1002/Fitspine+Traine r+Inversiontable 09/02/12

Appendix A5 IronMan LXT850 Locking Inversion Table The IronMan LXT850
Locking inversion table comes equiped with a racheting mechanism to lock it at 10 different angles. Features include:  Comfortable ankle holder to prevent pinch point pressure  Foam backrest with lumbar support  Supports up to 300lbs  Side holder for cell phones, glasses, wallets, etc.  Extended handles to return body to upright position. This model only allows locking in ten positions. The price point for this model is $250, but other models range up to $330. As with other inversion tables, the machine cannot be used for exercising anything other than abdominal muscles. http://www.overstock.co m/Sports- Toys/Ironman-LXT850- Locking-Inversion- System/3987541/produc t.html 09/02/2012

Appendix B1 APPENDIX B – SURVEY Home Gym and Inversion
Table CUSTOMER SURVEY There is a gap in the market for home gyms that also give the user the ability to stretch after working out. This purpose of this survey is to gather data about the current satisfaction with home gyms and inversion tables. How important is each feature to you for the design of a home gym? Please circle the appropriate answer. 1 = low importance 5 = high importance Avg. Price 1 (0) 2 (0) 3 (4) 4 (4) 5 (6) N/A (0) 4.14 Capacity for varied user height/weight 1 (0) 2 (2) 3 (3) 4 (6) 5 (3) N/A (0) 3.71 Ease of operation 1 (0) 2 (1) 3 (1) 4 (4) 5 (8) N/A (0) 4.36 Ease of assembly 1 (0) 2 (4) 3 (3) 4 (4) 5 (3) N/A (0) 3.43 Quiet operation 1 (2) 2 (3) 3 (4) 4 (2) 5 (2) N/A (0) 2.92 Comfort 1 (1) 2 (2) 3 (3) 4 (6) 5 (2) N/A (0) 3.43 Stability 1 (0) 2 (0) 3 (1) 4 (4) 5 (9) N/A (0) 4.57 Small footprint 1 (3) 2 (2) 3 (4) 4 (3) 5 (2) N/A (0) 2.93 Safety 1 (0) 2 (1) 3 (3) 4 (4) 5 (6) N/A (0) 4.07 Ease of maintenance 1 (1) 2 (0) 3 (4) 4 (7) 5 (2) N/A (0) 3.64 How satisfied are you with the current home gyms or inversion tables currently on the market? Please circle the appropriate answer. 1 = very unsatisfied 5 = very satisfied Avg. Price 1 (0) 2 (5) 3 (5) 4 (4) 5 (1) N/A (3) 2.73 Capacity for varied user height/weight 1 (1) 2 (1) 3 (7) 4 (2) 5 (2) N/A (1) 3.23 Ease of operation 1 (1) 2 (1) 3 (3) 4 (7) 5 (0) N/A (1) 3.46 Ease of assembly 1 (1) 2 (4) 3 (2) 4 (2) 5 (0) N/A (4) 2.80 Quiet operation 1 (0) 2 (1) 3 (5) 4 (4) 5 (3) N/A (1) 3.69 Comfort 1 (1) 2 (0) 3 (6) 4 (5) 5 (1) N/A (1) 3.38 Stability 1 (0) 2 (0) 3 (3) 4 (7) 5 (3) N/A (1) 4.00 Small footprint 1 (0) 2 (3) 3 (4) 4 (5) 5 (0) N/A (2) 3.17 Safety 1 (1) 2 (0) 3 (3) 4 (6) 5 (3) N/A (1) 3.77 Ease of maintenance 1 (0) 2 (4) 3 (3) 4 (6) 5 (0) N/A (1) 3.15

Appendix C1 APPENDIX C – QUALITY FUNCTION DEPLOYMENT ANALYSIS Handles
Ankle supports Roller Bearings Standard hardware Foldable frame Coated or stainless steel Rubber corners and feet Symmetrical Design Back rest Standard tools used for assembly Customer importance Designer's Multiplier Current Satisfaction Planned Satisfaction Improvement ratio Modified Importance Relative weight Relative weight % Price 1 3 1 9 3 9 1 1 1 4.14 1.10 2.73 3.50 1.28 5.84 0.13 13% Capacity for varied height/weight 9 3.71 1.00 3.23 3.50 1.08 4.02 0.09 9% Ease of Operation 9 1 1 4.36 1.10 3.46 4.00 1.16 5.54 0.13 13% Ease of assembly 1 9 3 9 3.43 1.00 2.80 3.00 1.07 3.68 0.08 8% Quiet operation 9 9 2.92 1.00 3.69 4.00 1.08 3.17 0.07 7% Comfort 9 1 9 3.43 1.10 3.38 3.50 1.04 3.91 0.09 9% Stability 1 3 9 4.57 1.10 4.00 4.00 1.00 5.03 0.11 11% Small footprint 9 2.92 1.00 3.17 4.00 1.26 3.68 0.08 8% Safety 3 9 9 3 4.10 1.00 3.77 4.50 1.19 4.89 0.11 11% Ease of Maintenance 3 1 9 9 3.64 1.00 3.15 3.50 1.11 4.04 0.09 9% Abs. importance 1.69 3.16 1.28 2.05 1.52 2.38 1.79 1.03 1.27 1.72 17.9 43.8 1.00 1.00 Rel. importance 0.09 0.18 0.07 0.11 0.09 0.13 0.10 0.06 0.07 0.10 1.0 Aaron Crum Home Gym with Inversion Table 9 = Strong 3 = Moderate 1 = Weak

Appendix D1 APPENDIX D – PRODUCT OBJECT IVES Based on
the research, the product objectives are the list of features that are taken into consideration. The following is a list of product objectives and how they will be obtained or measured to ensure that the goal of the project was met. 11. Cost (13%) a. Prototype under $500 12. Ease of operation (13%) a. Adjustment between exercises requires ≤ 3 steps b. Adjusts from workout station to inversion table in ≤ 3 steps c. Mechanisms to help with inversion d. Inversion table can be locked in all angles from horizontal to vertical with one hand e. Allows user ability to work out all muscle groups without reconfiguration 13. Stability (11%) a. Symmetrical design b. Consistent loading conditions and design for CG at or below comparable machines c. Frame to be welded instead of fastened 14. Safety (11%) a. All corners covered with rubber bumpers b. Ankle supports to lock to prevent falling c. No pinch points d. Safety bars on side of machine 15. Capacity for varied user height/weight (9%) a. Adjustable positioning for heights between 5’0” – 6’6” b. Includes ankle supports for range of human ankles c. Material and design will be sized and selected based on a 3.0 safety factor 16. Ease of maintenance (9%) a. All steels are stainless or coated to prevent rust b. All bearings are sealed requiring no lubrication 17. Comfort (9%) a. Back rest is typical weight bench padding b. Ankle supports are adjustable and padded comparable to Teeter brand c. Handle grips will be ergonomic

Appendix D2 18. Ease of assembly (8%) a. Uses standard
hardware b. Uses standard tools for assembly and teardown c. Unit has ≤ 10 parts that need assembling 19. Small footprint (8%) a. Product to take up no more than 6’x4’ floor space b. Foldable frame to take up no more than 3’x4’ floor space 20. Quiet operation (7%) a. Contains roller bearings for smooth movements b. Uses rubber feet to prevent floor noise and vibration

Appendix E1 APPENDIX E – SCHEDULE TASKS Oct 14-20 Oct
21-27 Oct 28 - Nov 3 Nov 4 - 10 Nov 11 - 17 Nov 18 - 24 Nov 25 - Dec 1 Dec 2 - 8 Dec 9 - 15 Dec 16 - 22 Dec 23 - 29 Dec 30 - Jan 5 Jan 6 - 12 Jan 13 - 19 Jan 20 - 26 Jan 27 - Feb 2 Feb 3 - 9 Feb 10 - 16 Feb 17 - 23 Feb 24 - Mar 2 Mar 3 - 9 Mar 10 - 16 Mar 17 - 23 Mar 24 - 30 Mar 31 - Apr 6 Apr 7 - 13 Apr 14 - 20 Apr 21 - 27 Proof of Design to advisor 18 First Report 29 Full Senior Design Report 13 Concept sketches to advisor 1 3D Model - (Frame sub-assembly) 8 3D Model - (Rolling backrest sub-assembly) 15 3D Model - Full system assembled 6 System Analysis Calculations 6 Order Components 13 Bill of Materials 13 Oral Report to Faculty 17 Frabricate frame assembly 7 Fabriate rolling backrest assembly 28 Full Assembly and Testing 14 Modification and Tweaking 28 Customer Testing 4 Oral Report to Faculty 11 Project Final Report 18 Aaron Crum Home Gym with Inversion Table

Appendix G1 APPENDIX F – BUDGET Frame 40’ Tube steel
($2/ft.) $80 10’ Channel steel ($2.1/ft.) $21 Rolling Backrest Bearings $13 Wheels $19 Sheet of plywood $11 Shoulder bolts ($2.5/ea.) $10 Vinyl sheeting ($11/yd^2) $22 Foam padding $25 Inversion Table Pivot Joint and Handles Bar steel ($2.90/ft.) $3 Tube steel ($2/ft.) $8 Resistance System Handles $13 Resistance band set $20 Pulleys ($11/ea.) $22 Steel cable ($1/ft.) $10 Subtotal $277 20% Miscellaneous expenses $55 Total $333

Appendix G1 APPENDIX G – SHOP DRAWINGS

Appendix G1

Inversion tables do they work?

Inversion tables do they work?

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