FOLDING THREEWHEEL WHEELCHAIR

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FOLDING THREE-WHEEL WHEELCHAIR
Neeharika Bhartiya, Andrea Blakemore, Rebecca
Hung, Amanda Maguire
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PROBLEM
Three-wheeled Wheelchairs do not fit on public
transportation.
?
Western four-wheeled chairs are not as stable on
rugged terrain.
Ø
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CURRENT DESIGN
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FINAL DESIGN

• L-Shaped Bracket
• Modified X-Brace (two hockey sticks)
• Middle rod attaches to caster
• L shape allows front wheel to touch the ground
• Wheels attach from rods that extend down from the
  back
• Armrests form from long bent rods that extend
  through both L-Brackets to attach to the back of
  the chair

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Most Critical Module Prototype
Demonstrate Final Prototype!
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IMPORTANT DESIGN ELEMENTS

• Folding L-bracket
• Needed to find dimensions using geometry to
  optimize folded size
• Stresses on bars and joints
• Solved for reaction forces and stresses on middle
  rod to determine the strength and thickness of
  steel
• Height off of ground
• Chairs low to the ground can get stuck on
  obstacles
• Riders use wheelies to go over bumps
• Had to set a minimum height the frame had to be
  off the ground

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DESIGN SPECS MET

• Folded size folded size is similar to
• folding four wheeled wheelchairs
• Ease of Use Design is easy to fold unfold
• Loose Parts No loose parts
• Availability of Materials Only used parts that
  are already present on wheelchairs made in Africa

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DESIGN SPECS MET CONT.

• Cost Have not used any new or uncommon
  materials cost should not increase
• User Acceptability Appears similar to existing
  folding four wheel designs customers do not have
  to worry about the wheelchair appearing to be a
  new and unusual design

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PROBLEMS FACED

• Calculating forces and stresses
• Able to find forces on center rod
• Over-constrained system so it was hard to find
  all forces on the chair.
• Geometry
• Folded L-Brackets have parts sticking out when
  folded (W in diagram)
• Had to minimize W while still keeping frame
  reasonable height off the ground

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FUTURE IMPROVEMENTS

• Add wheels, footrests, armrests
• Better mechanism to hold brackets in place
• Figure out math to get best size pipes
• Thinner center rod (reduce weight)?
• Test as a chair and get user feedback!

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Wed like to thank our amazing lab instructor,
Amos Winter, Mark Belanger, Mike Tarkanian,
Gwyndaf Jones, Dennis Nagle, and Daniel Namkessa
from Mobility Care and Abdullah Munish from KCMC
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ANY QUESTIONS?
Website wddc.foldingwc.googlepages.com