Parking brake piston for a parking brake chamber

摘要

A spring-type brake actuator for a pneumatically-operated vehicle brake is provided, in which the parking brake release piston is formed from at least one stamped actuator piston plate, preferably a stamped aluminum plate. Preferably the biasing force of the power spring of the spring brake actuator bears on a stamped spring seat cap element which is interposed between the power spring and the stamped actuator piston plate. In addition, the parking brake release piston flexible diaphragm may be captured between the stamped actuator piston plate and a stamped backing plate by affixing the backing plate to a joining member, where the joining member includes a threaded insert to receive a manually-actuated parking brake release actuation tool.

主权项

1. A spring brake actuator, comprising:
an actuator intermediate flange member; a spring housing configured to be affixed to a first side of the actuator intermediate flange member to form a parking brake actuator chamber; a service brake housing configured to be affixed to a second side of the actuator intermediate flange member opposite the first side to form a service brake actuator chamber; a parking brake release piston comprising a stamped piston plate and a flexible diaphragm, the parking brake release piston being configured to divide the parking brake actuator chamber into a parking brake release chamber on an intermediate flange side of the parking brake release piston and a power spring chamber on an opposite side of the parking brake release piston; a parking brake actuating power spring arranged in the power spring chamber to bias the parking brake release piston away from a rear wall portion of the spring housing; a spring seat cap having at least a flange region arranged to transfer power spring biasing force between the power spring and the parking brake release piston plate in a region of an inner radius of the power spring, the spring seat cap having an axially-extending cap portion located within the inner radius of the power spring and extending from the flange region toward the spring housing rear wall portion; and a parking brake release operating rod affixed at a first rod end to the parking brake release piston and at a second rod end to a travel limiting member in the service brake actuator chamber, the operating rod having a rod length such that the travel limiting member abuts the second side of the intermediate flange before the spring cap contacts the spring housing when the parking brake release piston is located at a fully withdrawn position.