Patent attributes
A block manifold for a fail safe actuator system allows the actuator operation with a hand pump if electrical power were not available. A method is available to isolate fail safe solenoid valves and an accumulator from a hand pump circuit to relieve the stored energy from the fail safe circuit. An additional set of pilot operated check valves were installed between the motor driven pump circuit and the hand pump circuit. These pilot operated check valves isolated the hand pump circuit from the fail safe dump solenoid and accumulator. These pilot actuated check valves also hold the actuator in the fail safe position as long as the hand pump system was not used. There is also a hydraulic bleed circuit to relieve the accumulator stored energy when the hand pump system was used.
