Dutch Volunteers Help Design a One-Hand-Drive Wheelchair
The conventional wheelchair works well for persons who have strength in both upper limbs. But for persons who have only one strong hand and the other paralyzed, propelling the wheelchair is not easy. Persons who are hemiplegic (paralyzed on one side) from brain injury or cerebral palsy fall into this category.
For a number of years, Martin Perez, an innovative wheel designer who used to work at PROJIMO, and who is himself paraplegic from a bullet wound, was working on an all-terrain one-hand-drive wheelchair design. (Commercial hemiplegic wheelchairs break down quickly on rough roads.) But Martin had to leave Ajoya before his design was fully completed.
In the summer of 2001, two industrial engineering students from Delft University in Holland did an internship in Ajoya, where they helped design 2 different models of hemiplegic wheelchairs. In one model, the seat is placed low so that the person can use use his stronger leg (by pushing on the ground) to help propel and steer the chair.
The second model is the one-armed-drive wheelchair illustrated in Figure 1.
This “hemiplegic” or one-hand drive wheelchair is designed for the rider who has strength or control in only one hand. It has two hand-rims on the person’s strong side. The inner rim is drives the wheel on the side it is on. The outer rim drives the wheel on the far side.
Thus by pushing the inner rim, this young man makes a left turn. By pushing the outer rim, he turns to the right. By gripping and pushing both rims at once, he moves straight ahead (refer to Figure 2).
In the one-hand drive wheelchair, the outer hand-rim powers the wheel on the opposite site by means of a an axle which passes through the center of the hub on the rim side, and is attached to the wheel on the far side. The axle is built so that it can be folded like an accordion, to facilitate transport and in other circumstances where a folding wheelchair is needed.
This wheelchair, designed by the Dutch engineering students at PROJIMO, is much more sturdy and trouble free than the commercial hemiplegic wheelchairs in the USA, which are good for hospital wards but quickly break down in sandy or rocky terrain.
This one-hand drive wheelchair, built by Gabiel’s team for this girl with hemiplegic cerebral palsy (pictured in Figure 3), also has an easily adjustable angle to the back. A push button release on either side behind the backrest allows the angle of the back to be easily changed from upright to more horizontal. This allows her to change her position, from more upright for mobility and other activity, and more reclined for resting.