For many disabled people, the only way to move around is by using a wheelchair. Those who cannot afford powered wheelchairs propel themselves with their arms, which often leads to fatigue, pain, and even permanent damage to arms and shoulders.
In 2007, a group of mechanical engineering students from the Massachusetts Institute of Technology decided that the wheelchair needed a new design.
Amos Winter, now an MIT professor, came up with an innovative idea for a wheelchair propelled by levers. The group formed a company called Global Research and Innovation Technology (GRIT) and started manufacturing what they call the Leveraged Freedom Chair.
GRIT’s chief technology officer, Mario Bollini, said that "instead of grabbing on the wheels, like you would with the regular wheelchair, you grab these levers that you can push with either hand — kind of like a bench press. And it uses a bicycle drivetrain, very similar to what you have on your bike, to transfer power from these levers to the wheels.”
Other wheelchairs are also based on push-lever technology, but Bollini said GRIT's design is unique in at least two important areas.
“Our core technology is this lever drivetrain that you’re able to make entirely out of bike parts," he said. "And so that lets us have a really low-cost design, especially compared to the other competitors in the U.S., for about half the price of the next closest chair on the market, with, I think, better performance in our drivetrain. In addition to that, we’re the only drivetrain that lets you change the mechanical advantage by where you grab the lever.”
Bollini said the leveraged wheelchairs are especially useful for moving over the rugged surfaces often encountered in developing countries.
“We’ve had chairs in India for multiple years that are still performing great, and chairs in sub-Saharan Africa that are also doing very well out in the field," he said. "And most importantly, we have designed the chair so that every part is easily found on the local markets.”
If a wheel or a chain breaks, it can be replaced with a regular bike wheel and regular bike chain.
The production started in 2011, and Bollini said that last year, GRIT shipped almost 1,200 Leveraged Freedom Chairs to 17 countries. They are mostly sold to aid agencies and NGOs, which distribute them free of charge.
The company plans to design an equally affordable folding model.