Design Of Tuck-Away Manual Wheelchair Brakes

The goal of this project was to design, test and deliver a final manufactured manual wheelchair brake that would not interfere with the propulsion path of the user or injure the hand of the user in any way. Existing brakes often interfere with the individual’s propulsion stroke and require frequent adjustments. Some brakes also cause injuries to the hands that could potentially be avoided with a tuck-away brake system. The MQP team first studied the forces involved in wheelchair propulsion and the stroke patterns of an individual using the wheelchair to create a set of functional requirements for the final design. Then, twelve conceptual designs were generated that addressed the gears, the spokes, the grips, the toggle bar, the mount, and the locking mechanism of the brake system. A design matrix was applied to determine the final three brake designs and engineering drawings were produced to assist with manufacturing process. The brakes that were manufactured were the Modified Quadra, the Bicycle Brake, and the Sliding Toggle Brake. The Modified Quadra was made up of five parts including the tube, the shaft, the handle, the brass cap, and the knurl brake. The Bicycle brake was composed of the support tube, the brake arm, and the mounting bracket. The components of the Sliding Toggle brake were the base tubes, the telescoping link, the brass-bearing link, the mount, and the modified handle for a four-bar toggle brake. Each manufactured brake was tested and evaluated according to the design specifications and recommendations were made according to analysis of the results and consultation with students and caregivers at the Massachusetts Hospital School. The recommendations made for the Modified Quandra indicated that the angle of the brake should be minimized in order to decrease the amount of friction to allow smoother motion of the braking mechanism. Recommendations for the bicycle brake involved the use of a larger brake caliper to allow for better gripping of the brake, as well as easier adjustment by the user. Recommendations made for the Sliding Toggle brake involved modification of the handle to allow for more stowage underneath the seat