Parking Brake Chamber Internal Breathing System

摘要

A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the portion of the brake actuator containing the parking brake actuation power spring is arranged to be vented to atmosphere but not to permit entry of outside environmental air into the power spring chamber, the spring-type brake actuator being provided with an internal breather valve which permits clean dry air from the parking brake release chamber to enter the power spring chamber which the pressure difference between the chambers falls to within a predetermined pressure range.