Design and Modification of One Arm Driven Manual Hemiplegic Wheelchair

This paper presents a design modification to the existing standard wheelchair by incorporating an improved propulsion system and also braking and tilting systems that allow its full control with only one hand. The proposed design has the propulsion system with a chain drive powered through a four bar linkage driven by the main handle. The desired direction of motion is obtained by moving the lever in opposite directions. Disk brakes mounted on each of the wheels are operated through a brake lever attached to the handle near the main propulsion lever. The design involves a detachable lever operated lead screw that can be fitted to a wide range of wheelchair models. The leadscrew operated lifting mechanism helps to raise the seat cushion and tilt the backrest that facilitates easy shifting of the patient to bed or stretcher, etc. The design of the wheelchair mechanism is based on the anthropometric data for transfer of clients to bed. The proposed design has the merits of the mechanical advantage of requiring lesser force to operate and improved speed of operation due to a velocity ratio of the chain drive.