Spring applied parking brake assembly having a manual quick release feature

摘要

A spring applied parking brake assembly for a railroad vehicle braking system is provided for an automatic application of the parking brake in the absence of an air source. The spring applied parking brake assembly comprises a cylindrical casing containing a piston assembly. The piston assembly is mounted for longitudinal movement within the casing upon the application and/or removal of pneumatic pressure to the piston assembly. The piston assembly is associated with a force transfer lever of the braking system so as to apply a force to this force transfer lever upon longitudinal movement of the piston assembly. At least one spring member is provided within the cylindrical casing. This spring member applies a constant force to the piston assembly such that longitudinal movement of the piston assembly automatically occurs upon removal of pneumatic pressure to the braking system, causing the piston assembly to retract within the casing and the force transfer lever to rotate in a direction to initiate a brake application. Thus, once the train is removed from the train consist and the air supply for the pneumatic braking system has been disconnected, the brakes of the train are automatically applied. A manual quick release system is also provided which allows the parking brake to be released during shunting operations or anytime that it is desirable to move the vehicle in the absence of air.