Fluid pressure operable actuators.

摘要

In a combined service brake actuator and spring force brake actuator, the spring force actuator portion has a tubular force output member (40) which passes through a seal assembly (41) to act against the push-rod assembly of the service brake actuator and a breather check valve arrangement (49) is provided carried by the tubular output member (40) the check valve having an actuation device which responds to pressure drop in the non-pressure chamber of the spring force actuator to unseat the check valve allowing air flow thereto from the service brake circuit. <IMAGE>