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Wheelchair Accessible ATV

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

Patrick Tribble

August 2013

Thesis Advisor: Dr. Ahmed Elgafy

ii

ACKNOWLEDGEMENTS

I would like to express my deep gratitude to Professor Elgafy, Chris Kubic, and the

volunteers with May We Help for their patient guidance, enthusiastic encouragement and

useful critiques of my research and my project. I would also like to thank Dean Arthur Allen

for his advice and time when I needed assistance. My grateful thanks are also extended to the

Mechanical Engineering Technology faculty for their feedback during my presentations.

I would also like to thank Brittany Franklin for her help with finding resources and

useful contacts to assist me with the concept designs and fabrication of my project.

Finally, I would like to thank my parents for allowing me to use their garage as a place to

work on and store my project.

iii

TABLE OF CONTENTS

ACKNOWLEDGEMENTS ...................................................................................................... II

TABLE OF CONTENTS ........................................................................................................ III

LIST OF FIGURES ................................................................................................................ IV

LIST OF TABLES ................................................................................................................... V

ABSTRACT ............................................................................................................................ VI

INTRODUCTION .................................................................................................................... 1

BACKGROUND .................................................................................................................................................... 1 INTERVIEWS ....................................................................................................................................................... 2

EXSISTING PRODUCTS ........................................................................................................ 3

SELF-MODIFIED PRODUCTS ................................................................................................................................ 3 EXISTING HANDICAPPED ACCESSIBLE PRODUCTS .............................................................................................. 4

CUSTOMER FEEDBACK, FEATURES, AND OBJECTIVES ............................................. 6

SURVEY ANALYSIS ............................................................................................................................................. 6 PRODUCT OBJECTIVES ........................................................................................................................................ 7 ENGINEERING CHARACTERISTICS ....................................................................................................................... 8

DESIGN .................................................................................................................................... 9

CONCEPT DESIGNS ............................................................................................................................................. 9 CURRENT DESIGN ............................................................................................................................................... 9

CALCULATIONS .................................................................................................................. 13

STARTING PARAMETERS ................................................................................................................................... 13 REQUIRED TORQUE & HORSEPOWER ................................................................................................................ 13 MOTOR & REDUCER SELECTION ...................................................................................................................... 14 BRAKING TORQUE ............................................................................................................................................ 14 POWERING OF THE SYSTEM ............................................................................................................................... 15 FORCES IN THE SYSTEM .................................................................................................................................... 16 DESIGN FACTOR ............................................................................................................................................... 18 MATERIAL SELECTION ..................................................................................................................................... 19

SYSTEM CHANGES ............................................................................................................. 20

POWERING OF THE SYSTEM CHANGES ............................................................................................................... 20 OBJECTIVES CHANGES ..................................................................................................................................... 20

FABRICATION ...................................................................................................................... 22

DE-ASSEMBLY OF THE ATV FRAME ................................................................................................................. 22 ASSEMBLY OF FRAME, CART, AND PLACEMENT ON THE ATV ......................................................................... 23 ATTACHMENT OF LAWNMOWER PARTS ............................................................................................................ 25

RESULTS ............................................................................................................................... 29

MOVEMENT TESTING ....................................................................................................................................... 29 WEIGHT TESTING ............................................................................................................................................. 29 FINAL PRODUCT ............................................................................................................................................... 29

iv

SCHEDULE AND BUDGET ................................................................................................. 31

SCHEDULE ........................................................................................................................................................ 31 BUDGET ............................................................................................................................................................ 32

WORKS CITED ..................................................................................................................... 33

APPENDIX A- RESEARCH .................................................................................................... 1

APPENDIX B – SURVEY WITH RESULTS ......................................................................... 1

APPENDIX C – QUALITY FUNCTION DEPLOYMENT .................................................... 1

APPENDIX D – PRODUCT OBJECTIVES ............................................................................ 2

APPENDIX E – SCHEDULE .................................................................................................. 1

APPENDIX F – BUDGET ....................................................................................................... 1

LIST OF FIGURES

Figure 1-Custom ATV (4) ........................................................................................................ 3

Figure 2-Custom ATV rear (4) ................................................................................................. 3

Figure 3 - 906 ELC Plunger Accelerator (5) ............................................................................ 4

Figure 4 – Classic Hand Control Knob Grip Straight Handle (Model 3501KB) (6) ................ 5

Figure 5 – First and Second Design Concepts .......................................................................... 9

Figure 6 – ATV cart design .................................................................................................... 10

Figure 7 – Frame Brackets ...................................................................................................... 10

Figure 8 – Frame of ATV ....................................................................................................... 11

Figure 9 – Rear axle mount ..................................................................................................... 11

Figure 10 – Front axle mount.................................................................................................. 12

Figure 11 – Top view of cart with rear axle and wheels attached .......................................... 12

Figure 12 – Reactions for three supports under evenly distributed load (8) ........................... 17

Figure 13 – Deflection diagram of the ATV cart .................................................................... 17

Figure 14 – Guidelines for Design Factor with ductile materials (9) ..................................... 19

Figure 15 – Disassembled front of ATV................................................................................. 22

Figure 16 – Disassembled rear of ATV .................................................................................. 22

Figure 17 – Disassembled middle section of ATV ................................................................. 23

Figure 18 – Disassembled ATV .............................................................................................. 23

Figure 19 – Attaching the frame to front of ATV ................................................................... 24

Figure 20 – Completed frame of ATV .................................................................................... 24

Figure 21 – 6061-T6 Cart welded together ............................................................................. 25

Figure 22 – Opening in cart with Styrofoam tubing around edges ......................................... 25

Figure 23 – Murray riding lawnmower ................................................................................... 26

Figure 24 – 11.5hp motor from riding lawnmower ................................................................ 26

Figure 25 – Lawnmower rear axle with tubing attached ........................................................ 27

Figure 26 – Lawnmower axle welded to ATV ....................................................................... 27

Figure 27 – Front end of lawnmower attached to rear ............................................................ 28

Figure 28 – Motor placed onto ATV with belt attached ......................................................... 28

Figure 29 – ATV final product (rear view) ............................................................................. 29

v

Figure 30 – ATV final product (front view) ........................................................................... 30

Figure 31 - Budget .................................................................................................................. 32

LIST OF TABLES

Table 1– Customer importance and customer satisfaction ratings 6

Table 2– Engineering characteristics 8

Table 3 – Senior Design Project Schedule 31

vi

ABSTRACT

Many handicapped individuals that cannot enjoy some of the simple task that most able

bodied people can achieve are now beginning to do what they love to do. This is being made

possible by the great volunteers of the May We Help organization. Ideas are brought to life

with a common goal of helping someone in need. A damaged all-terrain vehicle was to be

made of use to a wheelchair user. What better than to allow the wheelchair user to be able to

access the ATV just like any abled bodied person could? This question brought me to

designing and fabricating an ATV that could be driven by someone in a wheelchair while

they are in their chair.

Throughout the duration of the project the ATV was extended with use of steel rods and

an aluminum cart was fixed on the supports to allow a wheelchair user to fit inside. An old

lawnmower was then stripped of some components and then placed onto the ATV to power

the system. The end results were a very reliable structure with a bigger motor needed to run

the system. My research proves that with thought an reliable backing, more handicapped

individuals can do what they love to do regardless of their handicap.

Wheelchair Accessible Electric ATV Patrick Tribble

1

INTRODUCTION

BACKGROUND

Dean Allen Arthur of the University of Cincinnati, sent out a mass email to students

concerning an old all-terrain vehicle that was in a fire and could possibly be used for a senior

project. The meeting with Mr. Allen took place on September 17th, 2012 about the all-terrain

vehicle and possible senior design projects. Mr. Allen talked about an all-terrain vehicle that

was brought to his attention by the May We Help organization. He said the vehicle was in a

fire and the only working parts on the vehicle were the wheels, frame, and the brakes. He

also said that the organization wanted it to be run off electricity also, which meant the vehicle

would have to be converted. He contacted the organization and got times for which they were

open so the vehicle could be shown off and to get to know some of the people in the

organization.

The May We Help (1) group is a non-profit organization that is comprised of skilled

engineers and volunteers that gather together to create customized devices and adaptations

for people with specific needs at no cost. These include projects such as an indestructible

dressing stick for an individual with no arms, a children’s shower chair that was light enough

for the client to get in and out of the bathroom independently, and a computer and keyboard

stand designed to be used by a mouth stick user.

All-terrain vehicles are made for off-road driving such as in wooded, snow covered, or

swamp land type areas. With normal all-terrain vehicles, use by someone in a wheelchair or

with non-functioning legs would be very difficult. The user would have to get out of the

wheelchair and transfer their body into the vehicle. Without fully functioning legs, this would

be unsafe. Also, the user could not accelerate the vehicle because most all-terrain vehicles are

adapted for pedal usage. Essentially, if you are in a wheelchair you could not ride an all-

terrain vehicle.

This project with the My We Help organization would allow a user in a wheelchair or

who has non-functioning legs to operate and all-terrain vehicle while in their wheelchair. The

new modified all-terrain vehicle would have to work in a way where it gives the user the

same experience as if they were on a normal all-terrain vehicle. During the duration of this

project the goal is to work with the organization to make an all-terrain vehicle that can be

accessible by someone in a wheelchair or has non-functioning legs.


2

INTERVIEWS

During this project several interviews were conducted. One with Associate

Dean/Professor of College of Engineering and Applied Science Allen Arthur (2) and the

second with Engineering Organization Coordinator Chris Kubic (3) with May We Help. Both

interviews were conducted in September in Cincinnati Ohio concerning project ideas,

concept designs, and introducing the all-terrain vehicle being worked on.

Chris Kubic is the engineering organization coordinator with May We Help. The

meeting took place on September 18th

, 2012 during an open house meeting at the May We

Help main office. There, the vehicle was presented and possible ideas were discussed about

how to go about working on the vehicle. The organization also showed off recent and past

projects to give a sense of what they do and some of the people they help. Mr. Kubic

explained that the vehicle was brought in by the owner with the thought of it being useful to

the organization to help someone in need. The engineers there then had the idea to turn the

normal ATV into an ATV that could be driven by someone with non-functioning legs. They

also expressed the idea that they wanted it to be run off of electricity so that there would be

no emissions. That way the user wouldn’t have to purchase gasoline. Once the project was

established and approved, the research began.


3

EXSISTING PRODUCTS

SELF-MODIFIED PRODUCTS

There currently aren’t any all-terrain vehicles on the market that allow the user to be in-

chair while operating. But, there are vehicles out there that are custom built that give a

wheelchair user that ability.

Figure 1-Custom ATV (4)

Figure 2-Custom ATV rear (4)

Custom Ramp for

wheelchair access

Wheelchair user in chair while

operating

Hand controls for operation

All terrain capable


4

Looking at these custom designs sparked ideas for different concept designs. Looking at this

concept design there are both positives and negatives. Some positives with the design are that

it fits in the frame of a regular ATV and that hand controls are incorporated to give the user

all the control that he could not normally use with non-functioning legs. The negative with

this concept design is that the person enters and exits the vehicle through the rear. This would

allow the vehicle to move while trying to enter and exit. With my design, I want to limit the

motion of the person in the wheelchair. With this design it seems as if the user would roll

around in the vehicle depending on the motion of the vehicle. Also, this design has the rider

entering from the rear of the ATV.

EXISTING HANDICAPPED ACCESSIBLE PRODUCTS

For the design, hand controls would have to be incorporated due to the fact the intended

user would not have functioning legs. Looking at existing products, there are hand

accelerators that work similar to a push button that allows the user to accelerate the vehicle

with their hands, and also a hand crank that operates as an accelerator and brake. The plunger

accelerator is an accelerator that can be mounted to the dashboard in a car and it allows the

user to accelerate the vehicle with their thumb. It also has an auto lock out feature for

emergency braking situations (figure3). The negatives with this design are that the design

would be hard to operate due to the fact that you are accelerating with your thumb instead of

your hand.

Figure 3 - 906 ELC Plunger Accelerator (5)

Plunger which controls

acceleration in some handicapped

accessible vehicles.


5

This design is a hand control knob grip straight handle which works as an accelerator

and a brake. When pulling back on the knob you would accelerate the vehicle and when

pushing the knob away from you it would apply the break (figure4). This is also a

consideration that would be beneficial because you can do both operations with one handle.

The negatives with this design are that the device gets in the way and adds extra parts to the

vehicle which could lead to discomfort.

Figure 4 – Classic Hand Control Knob Grip Straight Handle (Model 3501KB) (6)

The knob that controls

acceleration and breaking in

some handicapped accessible

vehicles


6

CUSTOMER FEEDBACK, FEATURES, AND OBJECTIVES

SURVEY ANALYSIS

All of the ten wheelchair surveys distributed were returned and analyzed for customer

needs. All of the surveys were completed by handicapped individuals who were in a

wheelchair (Appendix B has survey results). The survey asked the individual about the

importance of 12 product features that would be incorporated with my design and the

importance of those features in existing products that they currently use. The importance and

satisfaction were rated from 1 to 5 with 1 being low and 5 being high. The quality function

development shows the ratings of the customer importance and satisfaction on the right side

of the table. These numbers were generated based off customer feedback from the surveys.

Table 1– Customer importance and customer satisfaction ratings

The survey results showed that safety, reliability, easy to adjust, and different terrain

capable were the most important features to the customer. With the findings, new design

concepts will address the desirable features of the customer.

Customer Importance Ratings

Safe 4.6

Reliable 3.9

Easy to Adjust 3.8

Different terrain compatible 3.6

Durable 3.5

Easy to Operate 3.4

Maneuverable 3.3

Compatible with wheelchair 2.9

Affordable 2.9

Easy to Store 2.8

Comparible speed of commercial ATV 2.6

Reduce Emissions 2.4

Customer Satisfaction Ratings

Durable 3.8

Easy to Store 3.2

Affordable 3.1

Reliable 3.1

Safe 2.9

Easy to Adjust 2.7

Reduce Emissions 2.6

Maneuverable 2.6

Comparible speed of commercial ATV 2.4

Different terrain compatible 2.1

Easy to Operate 2.0

Compatible with wheelchair 1.9


7

PRODUCT OBJECTIVES

The product objectives come from the list of features from the survey. The product

objectives are sorted by customer importance based off of survey results. Under each of the

listed features are the methods or intended designs that will be used in the prototype of the

vehicle.

1. Safe (12.5%)

a. Wheel locks for wheelchair

b. Emergency stop to cut electricity to motor

c. Standard ATV braking

d. Meets ATV/OFMC Regulations

2. Easy to Operate (11.9%)

a. Added accelerator on the handle for easy acceleration

b. Hand brakes like a standard ATV

c. Ramp mounted on vehicle for wheelchair access

3. Compatible with wheelchair (11.6%)

a. Wheelchair will lock in place in the ATV

4. Different terrain compatible (9.0%)

a. Able to drive in wooded areas

b. Able to drive in shallow water

5. Reliable (8.8%)

a. Low charging times

b. Low maintenance

6. Easy to Adjust (8.7%)

a. Adjustable Steering column for different wheelchair sizes

b. Adjustable height of ramp for different wheelchair sizes

7. Reduce Emissions (8.1%)

a. Electric motor has no emissions


8

8. Maneuverable (6.7%)

a. Standard ATV steering specifications

9. Comparable speed of commercial ATV (6.5%)

a. Will reach speeds that standard all-terrain vehicles can

10. Durable ( 6.2%)

a. Standard All Terrain Tires

b. 45amp/hour batteries

11. Affordable (5.3%)

a. Under $2500

12. Easy to Store (4.6%)

a. Will be able to store in standard 24x24ft garage

b. Will be able to tow in a standard 6.5ft truck bed for

transportation

ENGINEERING CHARACTERISTICS

Table 2– Engineering characteristics

The results from the quality function development chart show that latches wheelchair in

ATV, adjustable steering column, large tires, and ramp mounted on ATV for wheelchair

access are the most weighted features. I believe if I incorporate most of my efforts into these

features that I will have a desirable product.

Engineering Characteristics

Latches wheelchair in ATV 2.62

Adjustable steering column 1.82

Large Tires 1.51

Ramp Mounted on ATV for wheelchair access 1.42

45 amp/hour batteries 1.35

Large wheel base with low outside wheel cut 1.34

Accelerator on the handle 1.08

Fully charged within 3 hours 0.80

Electric motor 0.73

Will reach speeds that standard all terrain vehicles can 0.59

Under $2500 0.47

Will be able to store in standard 24x24ft garage 0.42


9

DESIGN

CONCEPT DESIGNS

Before selecting the final design, there were several other concept ideas that were drawn

up. With the intended usage of this project, there are only so many ways to go about

modifying the vehicle. To have and in chair design the frame must be modified to some

degree, there had to be some sort of ramp implemented that was able to open and close, and

at minimum had to be 3’ by 4 ‘ to satisfy manual wheelchair standard dimensions. With that

in mind, the first concept design had all three but the ramping mechanism and the entry point

were very difficult. In order for design one to work the back axel would have had to be

rebuilt entirely and extended several feet.

Figure 5 – First and Second Design Concepts

The second design shown in figure 6 allowed for a side entry which left open the

possibility of still leaving the rear axle intact. The brakes, wheels, and steering are still in

good condition on the vehicle and to keep those intact would save on funding. The second

design also had a turn style turntable that the vehicle would be locked in place to and would

turn into driver position once locked in. This was concept had a good principle to it but it was

just too difficult of a task to do. The turntable would have made the vehicle wider than

necessary. Both concepts had positives and negatives but they ultimately gave way to the

current design model.

CURRENT DESIGN

On the current model, side entry is installed for ease of entry and not having to

manufacture an extended rear axle. A locking ramp is in place so that the vehicle is

Design 1

Design 2


10

accessible by a wheelchair. 3/8” thick plating is used for the base of the cart and the sides of

the cart are 1/8” thick. The cart bolts to the frame of the ATV by use of brackets that hold the

support beams in place.

Figure 6 – ATV cart design

The selected design will extend the ATV by 4ft giving it a total 7.5ft wheel base. This still

allows the vehicle to be stored in a standard garage and a standard truck bed.

Figure 7 – Frame Brackets


11

Figure 8 – Frame of ATV

The vehicle is design to have a ramp that sits on the entry side of the vehicle which

collapses up by a catch and latch. The catch will be placed on the cart and when the ramp

extends upward and makes contact with the catch it will lock in place. The operator would

pull the ramp upward with a rope attached to the end of the ramp. The frame of the ATV is

designed to allow the whole cart structure to be bolted on and off and allow a means of

connecting the front and rear ends of the ATV.

Figure 9 – Rear axle mount


12

Figure 10 – Front axle mount

Figure 11 – Top view of cart with rear axle and wheels attached

The motor will be mounted on the rear of the cart in front of the back axle mount and bar

tubing. This will allow the drive train to be closer to the motor.


13

CALCULATIONS

STARTING PARAMETERS

Before beginning the calculations, certain limits and assumptions were made to establish

the parameters of the project. These included the desired speed, desired acceleration, wheel

chair size, gear ratio, shaft material, brake type, ATV weight, and the weight of the

individual operating the vehicle. The vehicle’s desired speed was to be close to the speed of a

normal ATV to give the user something close to the same experience. The Environmental

Protection Agency(EPA) states that an off –road vehicle is described as a vehicle that at least

reaches speeds of 25mph.With that in mind, the desired speed was set to a max of 25mph

with an acceleration of 10mph in 10 seconds. These parameters gave way to calculating the

actual acceleration and the revolutions per minute value at 25mph.

Desired speed = 25 MPH

Desired acceleration = 10 MPH in 10 seconds

= 10 Hour

Miles x 5280

Mile

Feet = 52800

Hour

Feet

= 5280 Hour

Feet x 1

Seconds

Hour

3600 = 14.67

Second

Feet

= 14.67 Second

Feet / 10 seconds = 1.47

2Second

Feet

REQUIRED TORQUE & HORSEPOWER

Once the vehicles acceleration was calculated, the force of the vehicle at that

acceleration was computed. This was done to determine the torque on the shaft from the

motor. For calculating total system weight, and assumption for the vehicle weight was made

by comparing a similar ATV with around the same size motor. With that assumption made,

the new electric motor weight was omitted and accounted for in the total ATV weight with

gasoline motor. The vehicle is designed to be used with a manual wheelchair and the max

weight the operator can be is 300 lbs.

Weight of the vehicle = ATV + Cart + Gearbox + Batteries + Wheelchair + Operator

= 324 lbs + 217 lbs + 20 + (40 lbs) x 2 + 45 lbs + max 300 lbs

= 986 lbs 31 slugs

At 1.47 2Second

Feet Force = 31 slugs x 1.47

2Second

Feet = 46 lbs

Torque = (Force x Distance) (46 lbs x 11″ Wheel Radius) = 506 in-lb

Once the required torque was established, then the horse power could be calculated by

taking the desired speed, converting from mph to rpm, then dividing the torque multiplied by

the rpm by 63000.


14

ute

inches

ute

onds

onds

hourx

ft

inches

mile

ft

hour

miles

min26400

min1

sec60

sec3600

1

1

12528025

rpmute

inches

382"22

min26400

P = 63000

Re SpeedRotationalquiredTorque

= 63000

382506 3.06 horsepower

MOTOR & REDUCER SELECTION

Once required horsepower was obtained then the motor selection process began. At

minimum the system requires a 3 horsepower motor, so anything above 3 horsepower would

be acceptable. A 5hp electric AC single phase motor was selected that outputs 1725 rpm.

With this motor, it causes the output torque to be 183 in-lb. The minimum torque required to

move at the desired acceleration and speed is 506 in-lb. With the value of torque being below

the needed, a speed reducer was introduced into the system. The reducer chosen reduces at a

rate of 5:1 which increased the torque value from 183 in-lb to 913 in-lb.

T = rpm

horsepower

1725

563000 183 in-lb

T = rpm

horsepower

1725

5563000 913 in-lb

BRAKING TORQUE

The braking torque for the new motor would be different from the torque caused by the

old, therefore the new braking torque would have to be calculated to see if the existing

system could supply the force needed. This was calculated by taking the horsepower of the

motor and multiplying it with a service factor and the conversion factor 63025. Once that

number was obtained, it was divided by the rear axle’s speed. For brakes under average

conditions it is recommended to use a service factor of 1.0.

Braking Torque = rpm

torServiceFacHorsepower63025


15

Braking Torque = 382

1563025 827 in-lb

The EPA states that, “ATV or off-road vehicle should have a braking horsepower equal

less than or equal to 30kw or 40hp (7)”. With this regulation, the max braking force of the

current brakes would be:

Braking Torque = 382

14063025 6599 in-lb

With the ATV complying with these regulations, the braking system will be able to handle

the new motors torque and bring the vehicle to a stop.

POWERING OF THE SYSTEM

With the motor selected, an accompanying power source had to be applied for the motor

to work. To power the system car batteries and an inverter will be placed on the vehicle to

supply the correct voltage to the motor. Since the car batteries supply DC voltage, an inverter

is needed to convert to AC voltage for the motor to use. The operating voltage of the motor is

208-230V AC at 60Hz power. This means that two 12V DC car batteries would be needed to

convert to 240V AC for the motor to work. A 24V DC to 220/240AC inverter was selected.

This would supply the correct voltage needed for the system to work with only two car

batteries required. Each battery has a reserve capacity of 170 minutes. This is the time it

takes for the battery to discharge until it reaches below its rated voltage. This means that you

could use the batteries at a rate of 25 amps for 340 minutes with two batteries. The motor

requires 21full load amps to reach max horsepower. So, at max hp, the system has a usage of

5 hours and 40 minutes. The two batteries will be placed on the outside of the ATV where

the front rack is located. Then, the inverter will be mounted on the left side of the front rack

so the wire from the batteries to the inverter is a short distance. A wire would then be run

from the inverter to the back of the cart where the motor lies. This would complete the circuit

and power the system.

Two Batteries = 24V

Inverter converts 24V DC to 220/240V AC

Motor uses 208-230V AC so the system would have the power necessary to work


16

FORCES IN THE SYSTEM

With the torque requirements met, the forces exerted from the torque on the shaft had to

be calculated. With a rotating member, torsional shear, bending, and tensile stress will be

present.

Tmax = J

aftRadiusofshTorque

Tmax = 4035.2

320175.1913

553 psi

Bending = ulusSectionMod

MaxMoment

Bending = 3035.2

3271288

86163 psi

Tensile = Area

Force 2035.2

4986

303.2 psi

The other members in the system that force will be exerted on the most will be the

bottom supports of the cart, and the base plate of the cart. At the supports there will be

deflection, shear, and bending stress from the distribution of the weight of the base plate

assembly with in-chair operator. At the base plate there will be bending stress from the front,

back, and side plates along with an in-chair operator. The deflection calculations were

calculated by using the figure below.


17

Figure 12 – Reactions for three supports under evenly distributed load (8)

Figure 13 – Deflection diagram of the ATV cart


18

L = 24 in

X1 = L4215.0 10.116 in

E = 30457924 psi

I = 64

4D .049

Deflection = 049.1030185

244576

4

x -.557 in

Reaction at B = 2445725.1 13710 psi

Reaction at A = Reaction at C = 8

244573 4113 psi

Moment at B = 224681125.0 12309 in-lb clockwise

Moment at A = Moment at C = 2025.126810703.0 6922 in-lb

Max Bending Stress = ulusSectionMod

MaxMoment 3035.2

3212309

14877 psi

Bending stress in base plate = ulusSectionMod

MaxMoment 23648

614232

1.37 psi

DESIGN FACTOR

With the forces on the system calculated, a design factor for the modifying parts had to

be selected. With the operator being physically impaired, it was assumed that when off-road

driving that the conditions be moderately normal with few obstructions which would reduce

impact and shock. My modifications are giving the operator the ability to experience riding

in an ATV in off-road conditions but not extreme conditions where there would be heavy

amounts of impact and shock. With these assumptions assumed, a design factor of 3 was

chosen. For ductile materials a recommended set of design factors is supplied in the figure

below. The design factor 3 will be adequate for the intended design usage.


19

Figure 14 – Guidelines for Design Factor with ductile materials (9)

MATERIAL SELECTION

With design factor chosen, the material for each component was selected. The selection

process of the material was based off of three factors. These factors are cost, design factor,

and forces obtained. The first material selected was the material of the support rods that run

along the bottom of the cart. The material chosen for the supports was high-strength 1045

carbon steel which has yield strength of around 77 ksi. The max stress the supports come

under is 14877 psi. If the yield strength of the material is divided by the design factor 3, the

value obtained is above the intended stress. This makes the material acceptable for use in the

supports.

Design Stress = orDesignFact

gthYieldStren =

3

900,76 25,633 psi

With the support material chosen the next material analyzed was the cart. The cart

includes the base plate, front panel, side panel, and back panel. The material chosen for all

four sides should be the same material for ease of welding the components together. To

reduce weight, aluminum materials were looked at because of their moderate strength with

low weight. The aluminum selected was 6061-T6 grade. The 6061 is adequate enough to

handle all the stress and forces on the cart body. The cart will not see as many forces as the

axel or supports so material was choose based on reduction of weight in the system. The

yield strength of the 6061-T6 is 40,000 psi which gives a design stress of 13,333 psi. This

makes the material acceptable for this application.

Various parts of the cart such as the support brackets and the axle mounts will be made

of 1018 steel. 1018 steel has a yield stress of 53,700 psi which gives it a design stress of

17,900 psi. The support brackets and axle mounts are there just as a means to connect the

existing ATV to the frame of the cart and the forces exerted on these members will not be

critical. The material will be suitable for the application.


20

SYSTEM CHANGES

POWERING OF THE SYSTEM CHANGES

The means to make the vehicle run by electric were too costly and the AC power would

not have been strong enough to sustain the vehicle for long periods of time as previously

thought. With these factors, the decision was made to go with a gasoline powered system to

reduce cost and to have longer usage times than with electricity. A Murray riding lawn

mower was purchased and stripped of its motor along with parts of the frame which were

used on the ATV. The motor of the riding lawn mower is rated at 11hp and rotates at max

2800 rpm. This will be adequate to power the system with at least a 3:1 speed reducer.

T = rpm

horsepower

2800

1163000 247.5 in-lb

T = rpm

horsepower

2800

31163000 742.5in-lb

OBJECTIVES CHANGES

With this change, the objectives of the project had to be restated also. The reduce

emissions, parts of durability, and reliability had to be changed from the previous objectives

to meet with current requirements.

1. Safe (12.5%)

a. Wheel locks for wheelchair

b. Emergency stop to cut electricity to motor

c. Standard ATV braking

d. Meets ATV/OFMC Regulations

2. Easy to Operate (11.9%)

a. Added accelerator on the handle for easy acceleration

b. Hand brakes like a standard ATV

c. Ramp mounted on vehicle for wheelchair access

3. Compatible with wheelchair (11.6%)

a. Wheelchair will lock in place in the ATV

4. Different terrain compatible (9.0%)

a. Able to drive in wooded areas

b. Able to drive in shallow water


21

5. Reliable (8.8%)

a. Low maintenance

6. Easy to Adjust (8.7%)

a. Adjustable Steering column for different wheelchair sizes

b. Adjustable height of ramp for different wheelchair sizes

7. Maneuverable (6.7%)

a. Standard ATV steering specifications

8. Comparable speed of commercial ATV (6.5%)

a. Will reach speeds that standard all-terrain vehicles can

9. Durable ( 6.2%)

a. Standard All Terrain Tires

10. Affordable (5.3%)

a. Under $2500

11. Easy to Store (4.6%)

a. Will be able to store in standard 24x24ft garage

b. Will be able to tow in a standard 6.5ft truck bed for


22

FABRICATION

DE-ASSEMBLY OF THE ATV FRAME

The first step of fabrication was to disassemble the ATV into pieces. Old wires were

trimmed from the frame and bolts were removed to take off components not needed. The

front of the frame was disassembled first.

Figure 15 – Disassembled front of ATV

Once the front of the ATV was removed the rear was removed which gave the necessary

pieces to start fabrication of the wheelchair ATV.

Figure 16 – Disassembled rear of ATV


23

Figure 17 – Disassembled middle section of ATV

Figure 18 – Disassembled ATV

ASSEMBLY OF FRAME, CART, AND PLACEMENT ON THE ATV

Once the ATV was in separate pieces, the lower frame was assembled and welded on to

the front section of the disassembled ATV. The lower frame was made by making three

carbon steel brackets by bending plates 90 degrees down the center. Once bent, the carbon

steel was drilled three times to allow the supports to slide through them. With the supports

through the brackets, each support was welded to the brackets at each hole location. The

front axle mount was then placed onto the supports to allow connection to the upper section

of the ATV. A steel section of tubing was also placed on the edge of the supports to allow for

connection to the rear section of the ATV.


24

Figure 19 – Attaching the frame to front of ATV

When the front end of the vehicle was attached the lower frame, the front end was raised

and to allow the correct placement. Once a solid weld was run then the frame was lowered

and the rear section of the ATV was welded on.

Figure 20 – Completed frame of ATV

Once the frame was completed, the 6061-T6 aluminum cart was welded together and

had 6 holes drilled on the bottom so that it could be bolted onto the frame. This was chosen

to be done this way to have a means to remove the cart if the cart were to be damaged

somehow. This way it could be replaced without having to replace the frame.


25

Figure 21 – 6061-T6 Cart welded together

Once the cart was attached to the frame, the cart’s front section was cut to allow access

to the steering wheel. Styrofoam tubing was then placed along the jagged edges of the cut

frame so that the user would not get cut while operating. A ramp was supposed to be placed

on the side of the cart but a means to do so would have been too expensive and taken up too

much time to meet deadline dates. Therefore, the ramp was excluded during the duration of

the project.

Figure 22 – Opening in cart with Styrofoam tubing around edges

ATTACHMENT OF LAWNMOWER PARTS

Due to the cost of making the ATV run off of electricity, a Murray riding lawnmower


26

was stripped of its rear axle, front end, and an 11.5hp motor to be placed onto the ATV so

that the motor could be used to run the system. The new plan was to implement the same

system as the riding lawnmower to push the ATV by using a pulley clutch attached to the

drive shaft of the motor which would be connected to the lawnmowers rear axle by a belt. A

sawzall, screwdriver, and ratchets were used to remove the needed pieces from the

lawnmower.

Figure 23 – Murray riding lawnmower

The 11.5hp motor was removed first so that the other components could be easily taken

off without an issue of damaging the motor. Bolts fastening the motor to the body of the

lawnmower were removed, along with the drive belt and pulleys which freed up the motor to

be removed.

Figure 24 – 11.5hp motor from riding lawnmower

The next step in fabrication was to remove the rear axle. A sawzall was run through the


27

rear of the lawnmower to remove the plastic body from the rear axle and bolts were removed

from the body, which were fastened to the axle, which freed the axle. Once the axle was

removed, steel tubing was connected to the axle to allow a means to connect to the rear of the

ATV.

Figure 25 – Lawnmower rear axle with tubing attached

Once the lawnmower parts were ready to be attached, the existing axle of the ATV was

removed so that steel tubing could be placed on to allow connection. When the proper

alignment was made the tubing pieces were welded together.

Figure 26 – Lawnmower axle welded to ATV

With the front end of the lawnmower removed, the next step was to place it onto the rear

of the ATV so that the motor could be placed on top of it and line up with the rear axle

pulley. This way motion could be achieved when the motor makes rotation, and drive the

wheels.


28

Figure 27 – Front end of lawnmower attached to rear

The final part of reconstruction was to place the motor onto the rear of the ATV. The

pulley clutch was attached to the shaft of the motor and holes were drilled into the top

portion of the lawnmower so that the motor could be bolted down. Once bolted down, a belt

was sized and placed onto the rear axle pulley and clutch.

Figure 28 – Motor placed onto ATV with belt attached


29

RESULTS

MOVEMENT TESTING

The planned testing of the ATV was to turn on the motor and see how fast it could

accelerate, stop, and the ease of turning on and off. The 11.5hp motor was not able to start up

so a new motor was purchased and placed on the system. The new motor is a 5.5hp motor so

accurate testing of the system could not be made. The new motor was able to move the

weight of the ATV with a chair placed on the inside of the cart but with a weight applied

(230lbs) it was able to move about a half a foot or so. With the old motor fixed the system

will be able to tow the design weight of at least 300lbs.

WEIGHT TESTING

The frame was tested by placing my weight plus a wheel chair into the cart and

observing if the system would give out or yield. The frame was sturdy while just sitting in the

wheelchair, so a shock test was made. While in the cart standing, I began to jump up and

down repeatedly to see if the cart would buckle or give. The frame withstood the shock and

was able to do so without deforming. The results of these test show that the frame is able to

handle the necessary stresses to operate properly.

FINAL PRODUCT

Below are the images of the final product with the replacement motor mounted onto the

rear, and the front view with Styrofoam tubing placed along the edges.

Figure 29 – ATV final product (rear view)


30

Figure 30 – ATV final product (front view)


31

SCHEDULE AND BUDGET

SCHEDULE

The project schedule begins on November 8, 2012 with meeting with the advisor for

proof of design and ends on August 2nd

, 2013 with project completion.

Table 3 – Senior Design Project Schedule

November December January February March April May June July August

Proof of Design to advisor 8

Concept sketches to advisor 15

Choose best concept design 20

Solidworks modeling 8

Design freeze 15

Desing Calculations 5 2

Order components 1

Assembly of ATV cart 14

Testing of Frame 30

Tech Expo 4

Redesign/Assembly of cart 7

Summer extension granted 24

Testing of ATV 12

Redesign of motor operation 22

Purchase of new motor 12

Re-test of the ATV w/new motor 18

Project Completion 2


32

BUDGET

The figure below shows my amounts for all of the items I needed when fabricating the

vehicle.

Figure 31 - Budget

Material Components or Labor Forecasted amout Actual amount

6061-T6 Aluminum for cart 500.00$ 670.00$

Murray riding Lawnmower 250.00$ 100.00$

1 in pulley clutch 80.00$ 80.00$

2 in pulley clutch 100.00$ 80.00$

5.5hp vertical shaft motor 150.00$ 110.00$

A size belt 10.00$ 8.00$

6' x 1" thick 1045 Carbon Steel rods 150.00$ 169.35$

Ramp Hinges with screws 55.00$ 61.68$

Ramp Grab Latch 5.00$ 10.13$

25 pk Steel Hinge Screws #10 thread 8.00$ 11.69$

Total 1,308.00$ 1,300.85$


33

WORKS CITED 1. May We Help. May We Help . [Online] [Cited: September 20, 2012.]

www.maywehelp.org.

2. Allen, Arthur. Possible Senior Project . Cincinnati, September 17, 2012.

3. Kubic, Chris. Wheelchair Accessible Electric ATV. Cincinnati, September 18, 2012.

4. 6x6 World. 6x6 World. [Online] [Cited: September 26, 2012.]

http://www.6x6world.com/gallery/argo-6-and-8-wheelers/p15539-wheelchair-accessible-

argo.html.

5. Ride-away. Ride-away Web site. [Online] [Cited: October 1, 2012.] http://www.ride-

away.com/products/driving-controls/guidosimplex/guidosimplex.php.

6. Able Data. Able Data website. [Online] [Cited: October 1, 2012.]

http://www.abledata.com/abledata.cfm?pageid=19327&top=13914&ksectionid=19327&prod

uctid=205666&trail=0&discontinued=0.

7. Environmental Protection Agency . Environmental Protection Agency web site. [Online]

[Cited: January 22, 2012.] http://www.epa.gov/nonroad/recveh/1-applicable-regs.pdf.

8. Mott, Robert L. Applied Strength of Materials. Upper Saddle River : Pearson Prentice

Hall, 2008. 0-13-236849-8.

9. —. Machine Elements in Mechanical Design. Upper Saddle River : Pearson Prentice Hall,

2004. 0-13-061885-3.

Appendix A1

APPENDIX A- RESEARCH

Interview with Engineering Organization Coordinator: Chris Kubic with May We Help

7525 Wooster Pike Cincinnati, Ohio 45227 9/18/12

He is the organizer of projects for the May We Help Organization. He has coordinated many

projects dealing with handicapped individuals and is also an engineer.

We talked about the tasks of the project and possible ideas of how to go about completing it.

To start off, he suggested stripping the ATV of its gasoline components and of its

transmission. Next task would be to design a new frame for the vehicle or to use the existing

frame and build an add on to it. Once the frame was figured out, then we talked about

putting the electric components into the vehicle, possible using 3-4 car batteries to power it.

When talking about design requirements, we both agreed that the ATV would have to have

hand controls due to the fact that the intended user would have non-functioning legs. We

also mentioned that the modified ATV should be easy to access by a wheelchair

user/individual with non-functioning legs and maybe a possible way to store the wheelchair

while the user is riding. Since the braking system on the ATV is functional, we talked about

possibly keeping that intact and maybe making small modifications to it if necessary.

He felt that the project upon completion would make the user it is for feel more able bodied

and give them the ability to do something that would normally be non-feasible.

Meeting with Associate Dean/Professor of College of Engineering and Applied Science:

Arthur Allen

7147 Garden Rd Cincinnati, OH 45236 9/17/12

We spoke about the project and ways to go about doing the project. He was alerted about the

project by the May We Help organization and he gave me the contact information of the

organization.

He suggested using an accelerator on the handle as the way to accelerate and also using the

transmission from a motorized wheelchair for use in the ATV. He also suggested keeping

the working parts of the ATV and just modifying the components that didn’t work.

Appendix A2

Custom Wheelchair Accessible Argo 8-wheeler

This is a custom ATV made for a person in a

wheelchair. With this design the intended user is to be

in the wheelchair while using. The ATV has a

collapsible ramp attached to the end for traveling in

and out of the ATV.

Custom ATV (4)

Custom ATV rear (4)

Design allows the user to move

while in the ATV.

My design would allow the user

to be out of the chair to give the

user a more comfortable

experience and eliminate rolling

inside of the ATV.

My design will be run off of

electric power.

Appendix A3

906 ELC Plunger Accelerator

This is an accelerator that can be mounted to the

dashboard in a car and it allows the user to accelerate the

vehicle with their thumb. This also has an auto lock out

feature for emergency braking situations.

906 ELC Plunger Acclerator (5)

Design would be hard to operate

due to the fact that you are

accelerating with your thumb

instead of your hand.

My design would have an

accelerator on the handle of the

ATV which would allow more

control.

CLASSIC HAND CONTROL KNOB GRIP

STRAIGHT HANDLE (MODEL 3501KB)

This is a push/pull mechanism that is mounted in the

vehicle and functions as a lever to accelerate and brake.

To accelerate, you would pull the lever towards you. To

brake, you would push the lever away from you.

Classic Hand Control Knob Grip Stright Handle (Model

3501KB) (6)

Device gets in the way, and adds

extra parts to the vehicle which

could lead to discomfort for the

user.

My design would be operated on

the handles of the ATV allowing

normal motion and comfort.

Appendix B1

APPENDIX B – SURVEY WITH RESULTS

Handicapped Accessible ATV

Customer Survey

The purpose of this survey is to gauge customer interest in an electric handicapped accessible

all terrain vehicle. Below is a list of features that the vehicle will incorporate.

How important is each feature to you for the design of a handicapped accessible ATV ?

Please circle the appropriate answer. 1 = low importance 5 = high importance

Averages

Safe 1(0) 2(0) 3(1) 4(2) 5(7) N/A(0) 4.6

Easy to Operate 1(2) 2(1) 3(1) 4(3) 5(3) N/A(0) 3.4

Reliable 1(1) 2(1) 3(1) 4(3) 5(5) N/A(0) 3.9

Durable 1(1) 2(1) 3(3) 4(2) 5(3) N/A(0) 3.5

Maneuverable 1(1) 2(1 3(3) 4(4) 5(1) N/A(0) 3.3

Easy to Store 1(2) 2(2) 3(3) 4(2) 5(1) N/A(0) 2.8

Compatible with wheelchair 1(3) 2(1) 3(3) 4(0) 5(3) N/A(0) 2.9

Reduce Emissions 1(3) 2(3) 3(2) 4(1) 5(1) N/A(0) 2.4

Comparable speed of commercial ATV 1(2) 2(3) 3(3) 4(1) 5(1) N/A(0) 2.6

Different terrain compatible 1(2) 2(1) 3(1) 4(5) 5(1) N/A(0) 3.6

Easy to Adjust 1(1) 2(1) 3(1) 4(3) 5(4) N/A(0) 3.8

Affordable 1(3) 2(1) 3(2) 4(2) 5(2) N/A(0) 2.9

How satisfied are you with the current wheelchair accessible vehicles?

Please circle the appropriate answer. 1 = very unsatisfied 5 = very satisfied

Averages

Safe 1(2) 2(2) 3(1) 4(5) 5(0) N/A(0) 2.9

Easy to Operate 1(4) 2(2) 3(4) 4(0) 5(0) N/A(0) 2.0

Reliable 1(2) 2(1) 3(2) 4(4) 5(1) N/A(0) 3.1

Durable 1(0) 2(1) 3(2) 4(5) 5(2) N/A(0) 3.8

Maneuverable 1(3) 2(0) 3(6) 4(0) 5(1) N/A(0) 2.6

Easy to Store 1(2) 2(2) 3(1) 4(2) 5(3) N/A(0) 3.2

Compatible with wheelchair 1(4) 2(3) 3(1) 4(1) 5(0) N/A(1) 1.9

Reduce Emissions 1(2) 2(2) 3(4) 4(2) 5(0) N/A(0) 2.6

Comparable speed of commercial ATV 1(3) 2(2) 3(1) 4(3) 5(0) N/A(1) 2.4

Different terrain compatible 1(5) 2(2) 3(1) 4(1) 5(1) N/A(0) 2.1

Easy to Adjust 1(1) 2(3) 3(4) 4(2) 5(0) N/A(0) 2.7

Affordable 1(2) 2(1) 3(4) 4(0) 5(3) N/A(0) 3.1

Appendix D1

APPENDIX C – QUALITY FUNCTION DEPLOYMENT

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Rela

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%

Safe 9 3 4.6 2.9 4.5 1.6 7.1 0.1 13%

Easy to Operate 9 3 9 3.4 2.0 4.0 2.0 6.8 0.1 12%

Reliable 3 9 9 3.9 3.1 4.0 1.3 5.0 0.1 9%

Durable 3 9 9 3.5 3.8 3.8 1.0 3.5 0.1 6%

Maneuverable 9 3.3 2.6 3.0 1.2 3.8 0.1 7%

Easy to Store 3 9 2.8 3.2 3.0 0.9 2.6 0.0 5%

Compatible with wheelchair 9 9 3 2.9 1.9 4.3 2.3 6.6 0.1 12%

Reduce Emissions 9 2.4 2.6 5.0 1.9 4.6 0.1 8%

Comparible speed of commercial ATV 9 2.6 2.4 3.5 1.4 3.7 0.1 7%

Different terrain compatible 9 3.6 2.1 3.0 1.4 5.1 0.1 9%

Easy to Adjust 9 3.8 2.7 3.5 1.3 4.9 0.1 9%

Affordable 9 2.9 3.1 3.2 1.0 3.0 0.1 5%

Abs. importance 2.62 1.82 0.80 1.51 0.73 1.35 1.08 0.47 1.34 0.42 1.42 0.59 12.1 56.9 1.0 1.0

Rel. importance 0.22 0.15 0.07 0.12 0.06 0.11 0.09 0.04 0.11 0.03 0.12 0.05 1.0

Patrick TribbleHandicapped Accessible ATV9 = Strong3 = Moderate1 = Weak

Appendix D2

APPENDIX D – PRODUCT OBJECTIVES

Appendix E1

APPENDIX E – SCHEDULE

November December January February March April May June July August

Proof of Design to advisor 8

Concept sketches to advisor 15

Choose best concept design 20

Solidworks modeling 8

Design freeze 15

Desing Calculations 5 2

Order components 1

Assembly of ATV cart 14

Testing of Frame 30

Tech Expo 4

Redesign/Assembly of cart 7

Summer extension granted 24

Testing of ATV 12

Redesign of motor operation 22

Purchase of new motor 12

Re-test of the ATV w/new motor 18

Project Completion 2

Appendix F1

APPENDIX F – BUDGET

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