A new wheel design by Salim Nasser — a NASA engineer, inventor and quadriplegic — can reduce the repetitive stress injuries that many wheelchair users face. Popular Science reports.
With standard manual wheelchairs, users have to grasp and push the rim extending from the back wheels. It’s okay for self-propulsion, but it takes a toll on shoulder and arm muscles.
This new wheel reduces the amount of energy expended by targeting bigger muscles: "Using a mechanical device called a planetary gear, Nasser redesigned the wheel hub so that users pull it backwards in a rowing motion to go forward. Planetary gears are used in automatic transmissions and power tools to reverse and reduce motion, but no wheelchair wheels on the market currently use this design."
Pulling uses larger, stronger muscle groups, while pushing a wheelchair uses little muscles in the front of the body (which also hunches over the upper body). This rowing motion reduces wear and tear, and users can stay upright (which improves breathing).
“If a typical user pushes 2,000 to 3,000 times a day, on average, my redesign came out to 330,050 less strokes a year,” Nasser says. The wheel can be fitted onto existing chairs.
He entered the design in the 2010 NASA Tech Briefs “Create the Future” competition, and won.
“Some 1.8 million folks use manual wheelchairs in the U.S. — so there’s a big market out there for these wheels,” says Rimas Buinevicius of Madcelreator, a company that helps early stage firms bring their ideas to market.
Nasser and Buinevicius cofounded Rowheels in 2012 and won the Wisconsin Governor’s Business Plan Contest that June. They hope to bring the wheel to market later this year. One wheelchair will probably cost between $2,000 and $3,000.
The beta design was recently presented at MedTrade in Atlanta and last month at the International Seating Symposium in Nashville.
Saturday, April 13, 2013
Posted by BA Haller at 8:59 PM