Updated Use Scenario 9/30/2014 P15007 Anti-Rollback Wheelchair
6 Aid Assists Client into Chair Client Propels Themselves on Flat
Terrain Aid Available for Steep Inclines/Declines Aid Instructs
Client to Engage/Disengage Hill Holding System Client Continues
Self Propulsion on Flat Terrain Aid and Client Interaction
Slide 7
System Architecture 9/30/2014 P15007 Anti-Rollback Wheelchair 7
Manual Wheelchair Disc Braking System Ratchet and Pawl System
Client / Aid Input Engagement
Slide 8
Functional Decomposition (1 of 3) 9/30/2014 P15007
Anti-Rollback Wheelchair 8 Main Function: Control Motion
Slide 9
Functional Decomposition (2 of 3) 9/30/2014 P15007
Anti-Rollback Wheelchair 9 Stop Backwards Motion Ratchet and Pawl
System
Slide 10
Functional Decomposition (3 of 3) 9/30/2014 P15007
Anti-Rollback Wheelchair 10 Impede Forward Motion Braking
System
Selection Criteria 9/30/2014 P15007 Anti-Rollback Wheelchair 12
Material CostEase to Transport Labor CostAbility to Complete in 2
Semesters Additional System WeightReliability Additional
WidthSafety COTS ComponentsAbility to steer down decline Ability to
prevent rollbackErgonomic Adjustability Ability to slow on
declineMaintenance Ability to stop on declineSystem Adaptability
Ease of CollapsibilityEase of Installation
Benchmarking: Monroe Wheelchair Visit 9/30/2014 P15007
Anti-Rollback Wheelchair 17 Jonathan Walters, Vice President Custom
VS Standard Options Rigid Frame VS Collapsible Frame Spoked Wheel
VS Spokeless Wheel
Slide 18
Benchmarking: Major Brands 9/30/2014 P15007 Anti-Rollback
Wheelchair 18
Slide 19
Benchmarking: Major Brands 9/30/2014 P15007 Anti-Rollback
Wheelchair 19
Slide 20
Benchmarking: Competitive Solutions 20 Parameters/ Products
Grade AidMagic WheelsThe Pivote-motionD's LocksADI Disc Brake
Cost$180~$5000~$4770$7,675.00 +$500+ $750+ (some over $1,150)
Weight~3 lbs~10 lbs (additional)~ 12 lbs (additional)10 lbs
(additional) +2 lbsNot Available FunctionAnti-rollback for incline
Hill holding and gear reduction Dual levers, Parking brake,
anti-rollback hill holder Slows Rollback and assists motion Locks
wheels to prevent chair from moving when transferring in / out of
chair. Manual Braking System Interfacing Replaces factory wheel
locks Replaces stock wheels Replacing quick-release rear wheels
Replaces stock wheels Attaches to wheel and stock axle Attaches to
quick detach wheels on custom chairs Limitations Works best with
inflatable tires Price Mostly Replaces current wheels entirely
Maximum Range of 16 miles, increases width by 1-1.5" Only used when
stationary Needs to be a quick detach wheel MaintenanceNot
Available Sealed gearbox, factory serviced only Not Available
Battery Recharge & Replacement none Occasional to replace pads
or rotor Universality Fits most Quickie wheelchairs Fits most
manual wheelchairs with supplied adapter(s), customers are asked to
call for verification Tube diameters 22.2mm, 25.4mm, 28.6mm, 30mm,
and 31.8mm (7/8", 1", 1 1/8", 1.2", and 1 1/4"). Only Compatible
with manufacturer specified wheelchairs. Compatible With specified
chairs, approx 50 models. Compatible with a various custom
chairs
Slide 21
Benchmarking: Grade Aid 9/30/2014 P15007 Anti-Rollback
Wheelchair 21
Benchmarking: ADI Disc Brake 9/30/2014 P15007 Anti-Rollback
Wheelchair 23
Slide 24
Scope: Retrofittable 9/30/2014 P15007 Anti-Rollback Wheelchair
24 Possible Target Wheelchairs Standard (Not Custom) Collapsible
Frame (Not Rigid) Standard Wheels (Not Quick-Release)
Slide 25
Scope: Users 9/30/2014 P15007 Anti-Rollback Wheelchair 25
Target Users: Men and Women Age 65+ Any WheelchairManual
wheelchairElectric wheelchair Number (1000s) % of population Number
(1000s) % of population Number (1000s) % of population Total
1,5990.611,5030.581550.06 Age Under 18 880.12790.11180.02 18-64
6140.395600.35900.06 65+ 8972.878642.76470.15 Gender Male
6580.526060.48840.07 Female 9410.78970.67710.05
Slide 26
Risk Assessment (1 of 2) 9/30/2014 P15007 Anti-Rollback
Wheelchair 26
Slide 27
Risk Assessment (2 of 2) 9/30/2014 P15007 Anti-Rollback
Wheelchair 27
Slide 28
Feasibility (1 of 3) 9/30/2014 P15007 Anti-Rollback Wheelchair
28 How long does our device have to last? Average wheelchair
lifespan, 5-15 years Insurance company funds replacement every 5
years Average wheelchair uses travels 1.6km per day Assume 24 wheel
1524678 revs in 5 years 4574034 revs in 15 years
Slide 29
Feasibility (2 of 3) 9/30/2014 P15007 Anti-Rollback Wheelchair
29 What loads does our device have to support? Assumed 300 lb load
limit Load applied directly at wheelchair center
Slide 30
Feasibility (3 of 3) 9/30/2014 P15007 Anti-Rollback Wheelchair
30 22 Inch Wheel Teeth \Pawls 123 401.730.860.58 601.150.580.38
800.860.430.29 24 Inch Wheel Teeth \Pawls 123 401.880.940.63
601.260.630.42 800.940.470.31 26 Inch Wheel Teeth \Pawls 123
402.041.020.68 601.360.680.45 801.020.510.34 What is the resolution
of the ratchet and pawl and how can we improve it?
Slide 31
Test Plan 9/30/2014 P15007 Anti-Rollback Wheelchair 31
TestEngineering Requirement Test ergonomics of controls Component
life tests through theoretical analysisDesigned test life Test
force input to brake down an incline using force gauge. Use
wheelchair ramp on campus that is standard 1:12 slope to conduct
test. Grip force exerted by user to brake on decline Measure
wheelchair width with and without system installed, and compare. Do
this for the wheelchair in the folded state and in use state.
Increase of wheelchair width when in use; Component interference
when wheelchair is folded Test hold on incline with maximum rated
load for standard wheelchair. Force exerted by user to hold
position on incline Measure total additional weight from
installation of the systemTotal system weight Measure time it takes
to detach the system and revert to original wheelchair
configuration Time to revert to original configuration
Slide 32
Project Goals: Phase III 9/30/2014 P15007 Anti-Rollback
Wheelchair 32 Further Evaluate Feasibility of Concept 1 & 2
Cost Analysis Maintainability Functionality Choose Final Ratchet
and Pawl Design Develop Prototype
Slide 33
Phase III Benchmark Opportunities 9/30/2014 P15007
Anti-Rollback Wheelchair 33 Dr. Day: CP Rochester Southside Medical
Supply Westside Medical Supply Access Lifts & Ramps