The Create the Future Design Contest has unveiled its winners and the grand prize goes to Salim Nasser out of Florida who designed and built a mechanism to modify wheelchairs to operate by pulling action rather than by pushing. The idea is that the stronger biceps take on more of the work, hopefully allowing for more endurance and greater control. It must be said that there must be an adjustment factor involved when switching to reverse controls.
Biomechanically, it offers a direct and more efficient solution to the problems of shoulder, elbow, wrist injuries, user fatigue and maneuverability, since the pulling motion transfers loads and stresses usually experienced by smaller and weaker muscles in the shoulder and arms to larger and more capable muscles in the upper back, shoulders, and arms, therefore, considerably reducing stresses and injuries experienced by the shoulders, triceps, and wrists.
The Rowheel has similar specifications and appearance to those of existing manual wheelchair wheels. The ability of the Rowheel to mount onto any standard manual wheelchair was of paramount importance and therefore, care was taken in incorporating standard, universal parts where necessary. The key feature of the Rowheel design involves adapting a planetary gear system at the center of the wheel, which reverses the pulling motion of the user into a forward motion of the chair. The unique change from pushing to pulling along with the mechanical advantage created by the use of the gear system will provide an overall increase in user endurance and range.
To operate a wheelchair with Rowheels, the user pulls a standard rim which is connected to the sun gear of the planetary system. This transfers the motion from the user to the wheelchair. The sun gear engages the planet gears (the planet carrier motion is fixed to the chair frame), which in turn engage a ring gear that is fixed to the hub which is fixed to the wheel through spokes. Large bore, small cross-section bearings fixed on to the inner and outer hub plates, allow relative motion between these plates and the inner and outer hub casings to occur.