SPRING FORCE APPLYING ACTUATORS

摘要

A spring brake actuator consists of an air pressure-responsive piston (8) and a heavy captive spring (11) which on release of air pressure applies force to a piston (8) for applying force to a brake and wherein the piston (8,13) is locked to the piston rod (20) by a locking mechanism (16,17) which is releasable by the application of a rotary motion to an externally accessible member (24) to enable release of the brake force without applying air pressure.