Combined service brake actuator and spring brake unit - with actuator compactly nested inside spring unit

摘要

As in previous combined units for vehicle wheel brakes spring force for emergency and/or parking brake application is normally opposed by a release piston subject to pneumatic or other fluid pressure in one cylinder. The service actuator has its own cylinder, suitably of hydraulic type with a piston which can also be mechanically operated by the spring unit. To obtain a compact assembly facilitating installation, the service cylinder is surrounded by the piston of the spring unit, and also by the spring, the latter piston thus being guided on the exterior of the service cylinder.