Imagine if the only way of propelling yourself on a bicycle was to reach down and turn one of the wheels with your hand. It would be pretty inefficient, yet that's essentially how a wheelchair works. Of course, wheelchairs are set up so that the push-rims can be reached very easily, but the propulsion process still comes down to the wheels being directly pushed forward by hand. ROTA Mobility, however, has an alternative. It's called the RoChair, and it's a wheelchair that is rowed by pushing and pulling on a front-and-center-mounted lever.
The ROTA powertrain takes the linear back-and-forth motion of the lever, and converts it into unidirectional rotary output. Depending on the selected gearing, one push-pull of the lever can translate into as much as two wheel revolutions.
Steering is accomplished by turning the adjustable-length lever to the left or right, while handlebar-mounted brake levers activate the wheelchair's dual disc brakes. A choice of eight gears is available, depending on whether users are going for maximum speed and efficiency on the flats, or making their way uphill.
As compared to traditional wheelchairs, the RoChair's push/pull propulsion system is said to not only offer a better mechanical advantage, but it is reportedly also less likely to cause repetitive strain injuries of the shoulders, wrists and hands. The chair still has traditional push-rims, however, for maneuvering at very slow speeds or in tight quarters.
It's also fairly narrow, with a width of 24 inches (61 cm). According to its designers, previous attempts at lever propulsion wheelchairs haven't used a front-and-center-mounted lever, and have thus ended up being wider. The RoChair additionally utilizes smaller-than-normal 20-inch wheels. These low wheels allow users to slide directly across from a chair onto its seat (its arm rests raise), without having to heave themselves up over one wheel. It's also designed to disassemble in seconds for car stowage.
ROTA Mobility also makes the three-wheeled RoTrike, for users who prefer the idea of a human-powered scooter over that of a wheelchair. Both devices are priced at US$4,980 each.
The video below shows them in use.
Source: Bicycle Design
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