The Leveraged Freedom Chair (LFC)

The Leveraged Freedom Chair (LFC) is an all-terrain wheelchair designed for rural areas of developing countries. The key innovation behind the LFC is its single-speed, variable mechanical advantage drivetrain. The user propels the chair by pushing on the levers; gasping high increases torque, while grasping low increases speed. The drivetrain geometry was optimized considering human power and force capabilities, user physiology, and terrain types found in the developing world. This simple system achieves a 3:1 change in mechanical advantage, enabling LFC users to travel 80% faster and produce 50% higher peak wheel torque than they could with a conventional wheelchair. All moving parts on the LFC are made from bicycle parts found anywhere in the world, making the LFC locally repairable and comparable in price to other wheelchairs available in developing countries. The LFC is in production in India and can be purchased through Global Research Innovation and Technology (GRIT).

Human upper body force and power outputs were used to optimize the drivetrain geometry for optimal performance on a wide range of terrains. All moving parts on the LFC are made from bicycle components, making the chair manufacturable and repairable anywhere in the developing world. The LFC is currently being trialed in Guatemala and India, with plans to start large-scale production in the summer of 2011 with BMVSS Jaipur Foot and its partners. Additionally, a developed world version of the LFC is under development in collaboration with Continuum.