Alternative Terrain Wheelchair

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Alternative Terrain Wheelchair

• Team 1 Team ARROW
• Brent Fischer
• Mitchell Kane
• Eric Goyette
• Brennan McVeigh
• Chris MacKenzie

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Outline

• Current Wheelchairs
• Design Requirements
• Considered Designs
• Selected Design
• Frame Drive
• Budget Schedule

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Current Wheelchairs

• Indoor Use Favored
• No Suspension
• No Gearing
• Soft Tissue Damage

Clipart - Wheelchair
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Alternative Terrain Wheelchair

• Braking Capabilities
• Gearing
• Suspension
• Repairable With Bicycle Components
• Ability To Reverse

SolidEdge Full Wheelchair
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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

SolidEdge Off-Axle Crank Design
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Considered DesignsSame Axle Wheel Drive

• Advantages
• No Learning Curve
• Familiar Design
• Disadvantages
• Too Many Chains
• Snag Hazard
• Unnatural Motion

SolidEdge Same Axle Wheel Drive
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Considered DesignsGears 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 DesignChains 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

• 29 Treaded Tires
• Mountain Bike Suspension
• Independently Driven Wheels
• Outer Hand Rims

Picture of Shock-absorber
SolidEdge Rear Suspension
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Frame Details

• Collapsible, Two Folding Cross Members
• All Aluminum Construction
• 1 Square Tubing

Picture of Tubing
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SolidEdge Frame
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Calculations - FEA

• Safety Factor of at Least 5
• Impact Load Factor of 3
• Bending
• Side Loading
• Angled Loading
• Design Considerations

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SolidEdge FEA
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Removable Seat

• Two Piece Seat
• Aluminum Framed
• Weather Resistant
• Locks on Frame

SolidEdge Removable Seat
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Adjustable Foot Rests

• Removable
• Adjustable
• Independent
• Convenient for Amputees

SolidEdge Foot Rests
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Safety System

• Waist Restraint
• Roll Bar
• Suspension
• Reflective Tape

SolidEdge Roll Bar
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SolidEdge Center of Gravity
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Drive System

• Front Castor Wheels
• Suspended Rear Wheels
• Chain Lever System
• Accessible Brakes, Gearing, Clutch

SolidEdge Full Wheelchair
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Chain Lever System

• Five Gears
• Available Parts
• Clutch to Reverse
• Chain Tensioner
• 0.79 to 2.45 Gear Ratio

SolidEdge Chain Lever System
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Clutch Assembly

• Located Centrally
• Non-Standard Clutch
• Easy to Assemble

SolidEdge Clutch Assembly
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Calculations Gear Ratios
Max Ratio
Min Ratio
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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

• Many off the Shelf Items
• Standard Metal Sizes
• Sponsorship Search Ongoing

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Schedule

• Construction to Start After Exam Period
• Aluminum Welding in Question
• Testing by February 1
• Completion by March 1

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Conclusions

• 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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