Alternative Terrain Wheelchair
Team # 1: Team ARROW
Brent Fischer
Mitchell Kane
Eric Goyette
Brennan McVeigh
Chris MacKenzie
Outline
Current Wheelchairs Design Requirements Considered Designs Selected Design Frame & Drive Budget & Schedule
2
Current Wheelchairs
Indoor Use Favored No Suspension No Gearing Soft Tissue Damage
3
[Clipart] - Wheelchair
Alternative Terrain Wheelchair
Braking Capabilities Gearing Suspension Repairable With
Bicycle Components
Ability To Reverse
4[SolidEdge] – Full Wheelchair
Considered DesignsOff-Axle Crank Drive
Advantages
Proven concept [VarnaHandcycle.com]
Fluid Hand Motion Constant Propulsion
Disadvantages Smaller Moment Arm Accessibility Issues Snag And Pinch Hazard
5
[SolidEdge] – Off-Axle Crank Design
Considered DesignsSame Axle Wheel Drive
Advantages No Learning
Curve Familiar Design
Disadvantages Too Many Chains Snag Hazard Unnatural Motion
6[SolidEdge] – Same Axle Wheel Drive
Considered DesignsGears with Lever Drive
Advantages Ease of Reverse Many Gear Ratios Large Moment ArmDisadvantage Complicated
Design Difficult to
Manufacture Difficult to Repair
7[SolidEdge] – Gears with Lever Drive
Selected DesignChains with Lever Drive
Advantages Easy to Repair Ergonomic
Controls Low CostDisadvantages Reverse has No
Mechanical Advantage
Requires Clutch
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[SolidEdge] – Chains with Lever Drive
Selected DesignFeatures: Roll Bar Adjustable Legs Rests Bench Press Style
Motion Many Standard Bike
Components Geared Drive
9[SolidEdge] – Full Wheelchair
Suspended Rear Wheels 29” Treaded Tires Mountain Bike
Suspension Independently
Driven Wheels Outer Hand Rims
10[SolidEdge] – Rear Suspension Picture of Shock-absorber
Frame Details Collapsible, Two
Folding Cross Members
All Aluminum Construction
1” Square Tubing
11 [SolidEdge] – Frame
Picture of Tubing
Calculations - FEA
Safety Factor of at Least 5
Impact Load Factor of 3
Bending Side Loading Angled Loading Design
Considerations
12 [SolidEdge] – FEA
Removable Seat
Two Piece Seat Aluminum Framed Weather Resistant Locks on Frame
13[SolidEdge] – Removable Seat
Adjustable Foot Rests
Removable Adjustable Independent Convenient for
Amputees
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[SolidEdge] – Foot Rests
Safety System
Waist Restraint Roll Bar Suspension Reflective Tape
15 [SolidEdge] – Center of Gravity
[SolidEdge] – Roll Bar
Drive System
Front Castor Wheels
Suspended Rear Wheels
Chain Lever System
Accessible Brakes, Gearing, Clutch
16[SolidEdge] – Full Wheelchair
Chain Lever System
Five Gears Available Parts Clutch to Reverse Chain Tensioner 0.79 to 2.45 Gear
Ratio
17[SolidEdge] – Chain Lever System
Clutch Assembly
Located Centrally Non-Standard
Clutch Easy to Assemble
18
[SolidEdge] – Clutch Assembly
Calculations – Gear Ratios
45.2368
900
mm
mm
r
r
w
a
79.034
1145.2
a
w
V
V
45.211
1145.2
a
w
V
V
19
2
1
n
n
r
r
V
V
w
a
a
w
Max Ratio
Min Ratio
Build Report Budget
Many off the Shelf Items
Standard Metal Sizes
Sponsorship Search Ongoing
SubTotal $1,877
Tax $263
Contingency (5%) $94
Total $2,234
Outside Donations $1,000
ME Departmental Donation
$1,000
Total $2,000
Net -$234
20
Schedule
Construction to Start After Exam Period Aluminum Welding in Question Testing by February 1 Completion by March 1
21
Conclusions
Design Requirements Met Design Essentially Completed Structural Materials Purchased Building and Testing March First
22
Special Thanks
Mechanical Engineering Faculty
Dr. Georgiades
Pam MacDougall
ME Class of 2007
23
Questions
24
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