HYDRAULIC RELEASE SYSTEM WITH MANUALLY OPERATED HYDRAULIC LOCK VALVE FOR SPRING-APPLIED, HYDRAULICALLY-RELEASED PARKING BRAKE SYSTEM

摘要

A hydraulic manifold assembly for use in a hydraulic release system operable to control a spring applied, hydraulically released parking brake assembly wherein a brake is movable between an applied position and a released position, a spring biases the brake towards the applied position, and a brake release actuator is selectively operable to release said brake against an application force imposed by said spring. The hydraulic manifold assembly comprises a manifold block and a manually operated hydraulic lock valve assembled in the manifold block. The manifold block includes a high pressure inlet port, an actuator port for connection to the brake release actuator, an outlet port for connecting to a hydraulic fluid reservoir, and an internal passage connecting the actuator port to the outlet port. The manually operated hydraulic lock valve is manually movable between an open position allowing flow of hydraulic fluid from the actuator port to outlet port and a closed position blocking flow of hydraulic fluid from the actuator port to the outlet port, whereby the hydraulic lock valve can be manually moved to its closed position to contain pressurized fluid in the actuator to keep the brake released, and manually moved to its open position for normal operation of the hydraulic release system.