Electric wheelchairs are an evolution of the traditional hand-pushed wheelchair/bath chair. They function in much the same way as manual wheelchairs, granting mobility to users over a wide range of terrains and inclines, however they’re selfpropelled, with a motor doing the hard graft.
As the chair is motorised, they also differ to manual wheelchairs in that they feature a systems platform beneath the seat. This platform – which is typically encased within a plastic shell – supports the motor as well as its power source (typically a battery array). The power pack is then connected via a wiring system to the motor, the seat and the wheelchair’s all-important control panel.
These controls, which are generally located on one of the armrests, enable the user to operate the majority of the chair’s functions. These include seat position (both elevation and tilt), motor power for speed alterations, directional movement – delivered through a joystick, plus system diagnostics.
Drive wheels on electric wheelchairs, unlike manual models, are fixed on a single plane, with an additional set, or pair of sets, found at the front and back of the chair to take care of guidance. These guide wheels are typically fitted with variable suspension struts and springs so the wheels remain in contact with the ground even on uneven surfaces.
Indeed, many modern electric wheelchairs are designed to cope with robust terrains, with large tracked wheels, reinforced pivot frames, pneumatic suspension units and high-torque motors allowing for cross-country use.
While wheeled platforms are recorded dating back to the 6th century BCE, one of the earliest references to wheelchairs being used in their modern incarnation comes from the 6th century CE. These are depicted in Chinese art carrying children, invalids and even emperors. These manually pulled cart-style chairs, however, were only the preserve of the rich and powerful, with wood, metal and those able to make them all in short supply. A good example of this can be seen in the inset image, which shows famous Chinese politician and philosopher Confucius being pushed around in his own bespoke wheelchair.