Leveraged Freedom Chair
MIT Mobility Lab, Amos Winter
Leveraged Freedom Chair (LFC) is a 3-wheeled, wheelchair designed for use on rough terrain with push levers to allow movement.
GRIT distributes the LFC via partners organizations, such as NGOs, government health units, hospitals, and others.
$250 USD Interview with representative
Free Wheelchair Mission, Rough Terrain Wheelchair (Motivation UK), RoughRider (Whirlwind Wheelchair International), ROC Wheels (Reach Out and Care). Here is a complete list of organizations distributing wheelchairs in the developing world (their own design and/or second-hand).
Goal 3: to improve and promote good health.
Disabled individuals in developing countries, who require a wheelchair that can function on rough terrain.
LFC kits are centrally manufactured and then distributed for local assembly through partner networks.
IP ProtectedUS Patent US8844959 B2
The LFC is sold in bulk (quantities of 100+) to NGOs, governments, and aid agencies serving the disabled in developing countries.
Over 1,500 LFCs have been distributed worldwide through partner organizations in 17 countries.
– – Rigid mild-steel frame
– – Three wheels
– – Adjustable rear axle position
– – 26 inch pneumatic bicycle tires
– – 8 inch solid rubber front castors
– – Adjustable footrest with straps
– – Fixed armrest with mudguard
– – Comfort cushion
– – Seatbelt
– – Chest and foot straps
– – Bicycle ball bearings on all bearing surfaces
– – Storable lever drivetrain and pushrims
– – Variable mechanical advantage from 1:1 to 3:1.
Measurements (standard size):
– – Seat depth: 14 inches
– – Length: 44 inches
– – Width: 26 inches
– – Seat width: 15 inches
– – Weight: 51 pounds.
Operation Overview: LFC riders push on levers, which are bio-mechanically more efficient than pushing on the wheels of a traditional wheelchair. Riders “”shift gears”” by sliding their hands up and down the levers. Grabbing low on the levers is a “high gear” enabling riders to travel 80% faster than a regular wheelchair on tarmac. Grabbing high on the levers is a “low gear,” enabling riders to power over obstacles with 50% more torque than a regular wheelchair.
LFCs must be properly prescribed for individual users. This requires support from local distribution partners, who ensure the LFC is correctly sized and appropriate for its user.
LFC is built from bicycle parts that are widely available around the world. LFC owners have reported using local bicycle shops to repair punctures, change bearings, and tune up their chairs.
LFC is designed to be easily repairable across the world to promote repairs rather than replacement.
Able to travel 5km/day on variable terrain;small and maneuverable enough to be used indoors; locally repairable using local tools, parts, and knowledge; provides good posture support.
Field tests show that compared to a conventional wheelchair on a dirt road, the LFC is about 78% faster, 41% more efficient in terms of metabolic effort, and able to put out 51% more torque.
A wheelchair that is not properly fit to the needs of an individual user can result in discomfort or injury (such as scoliosis or pressure sores) due to insufficient support or improper cushioning. There is also a risk of tipping while using a wheelchair.
The Design and Fabrication of the East African Trial Leveraged Freedom Chair (RESNA Annual Conference, 2010)
Stakeholder-Driven Design Evolution of the Leveraged Freedom Chair Developing World Wheelchair (Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition, 2012)
ISO International Standards for Wheelchairs, International Organization for Standardization.
Biomechanical Testing (field testing) Static, Impact, and Fatigue strength testing using a 200,000 cycle double-drum test (lab testing)
Empowering People Award winner
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