PNEUMATIC SYSTEM

摘要

A pneumatic braking system for a cycle or a wheelchair wherein the braking system is adapted to receive a bottle (12) pre-charged with compressed gas. The system comprises a gas pressure operated cylinder (2, 7) for connection to a brake of a wheel of the cycle or wheelchair and a control means (21, 33) to apply gas pressure to the cylinder or vent gas from the cylinder to apply the brakes. The system also has a pressure regulator (26) to regulate the pressure of gas emerging from the outlet. The source of compressed gas is a pre-charged bottle similar to those used to pressurise a domestic or industrial beer barrel. It can be charged to around 6900 kNm<-2> and has been found to give a long-lasting supply of air. The gas pressure acts to release the brakes, and the cylinders have a spring (35, 36) to oppose this action and apply the brake. Thus a ''fail-safe'' mechanism is provided as the brakes are gradually applied when the gas pressure falls.