Transcript Alternative Terrain Wheelchair - Mechanical Engineering Department

Alternative Terrain Wheelchair
Team # 1: Team ARROW
Brent Fischer
Mitchell Kane
Eric Goyette
Brennan McVeigh
Chris MacKenzie
Outline
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Current Wheelchairs
Design Requirements
Considered Designs
Selected Design
Frame & Drive
Budget & Schedule
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Current Wheelchairs
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[Clipart] - Wheelchair
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Indoor Use Favored
No Suspension
No Gearing
Soft Tissue Damage
Alternative Terrain Wheelchair
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Braking Capabilities
Gearing
Suspension
Repairable With
Bicycle
Components
Ability To Reverse
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[SolidEdge] – Full Wheelchair
Considered Designs
Off-Axle Crank Drive
Advantages
 Proven concept
[VarnaHandcycle.com]
 Fluid Hand Motion
 Constant Propulsion
Disadvantages
 Smaller Moment Arm
 Accessibility Issues
 Snag And Pinch Hazard
[SolidEdge] – Off-Axle Crank Design
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Considered Designs
Same Axle Wheel Drive
Advantages
 No Learning
Curve
 Familiar Design
Disadvantages
 Too Many Chains
 Snag Hazard
 Unnatural Motion
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[SolidEdge] – Same Axle Wheel Drive
Considered Designs
Gears with Lever Drive
Advantages
 Ease of Reverse
 Many Gear Ratios
 Large Moment
Arm
Disadvantage
 Complicated
Design
 Difficult to
Manufacture
 Difficult to Repair
[SolidEdge] – Gears with Lever Drive
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Selected Design
Chains with Lever Drive
Advantages
 Easy to Repair
 Ergonomic
Controls
 Low Cost
Disadvantages
 Reverse has No
Mechanical
Advantage
 Requires Clutch
[SolidEdge] – Chains with Lever Drive
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Selected Design
Features:
 Roll Bar
 Adjustable Legs
Rests
 Bench Press Style
Motion
 Many Standard Bike
Components
 Geared Drive
[SolidEdge] – Full Wheelchair
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Suspended Rear Wheels
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[SolidEdge] – Rear Suspension
29” Treaded Tires
Mountain Bike
Suspension
Independently
Driven Wheels
Outer Hand Rims
Picture of Shock-absorber
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Frame Details
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Collapsible, Two
Folding Cross
Members
All Aluminum
Construction
1” Square Tubing
Picture of Tubing
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[SolidEdge] – Frame
Calculations - FEA
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Safety Factor of at
Least 5
Impact Load
Factor of 3
Bending
Side Loading
Angled Loading
Design
Considerations
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[SolidEdge] – FEA
Removable Seat
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[SolidEdge] – Removable Seat
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Two Piece Seat
Aluminum Framed
Weather Resistant
Locks on Frame
Adjustable Foot Rests
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[SolidEdge] – Foot Rests
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Removable
Adjustable
Independent
Convenient for
Amputees
Safety System
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Waist Restraint
Roll Bar
Suspension
Reflective Tape
[SolidEdge] – Roll Bar
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[SolidEdge] – Center of Gravity
Drive System
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Front Castor
Wheels
Suspended Rear
Wheels
Chain Lever
System
Accessible
Brakes, Gearing,
Clutch
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[SolidEdge] – Full Wheelchair
Chain Lever System
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Five Gears
Available Parts
Clutch to Reverse
Chain Tensioner
0.79 to 2.45 Gear
Ratio
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[SolidEdge] – Chain Lever System
Clutch Assembly
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[SolidEdge] – Clutch Assembly
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Located Centrally
Non-Standard
Clutch
Easy to Assemble
Calculations – Gear Ratios
Vw ra n1
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Va rw n2
ra 900m m
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 2.45
rw 368m m
Max Ratio
Vw
 11
 2.45    2.45
Va
 11
Min Ratio
Vw
 11 
 2.45    0.79
Va
 34 
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Build Report Budget
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
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Many off the Shelf
Items
Standard Metal
Sizes
Sponsorship
Search Ongoing
Schedule
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Construction to Start After Exam Period
Aluminum Welding in Question
Testing by February 1
Completion by March 1
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Conclusions
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Design Requirements Met
Design Essentially Completed
Structural Materials Purchased
Building and Testing March First
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Special Thanks
Mechanical Engineering Faculty
Dr. Georgiades
Pam MacDougall
ME Class of 2007
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Questions
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