Abstract: A solenoid-actuated zero-leakage fail-safe three-position poppet-style four-way hydraulic directional control valve includes an arrangement whereby the inlet pressure P is connected to the inlet ports of first and second normally closed 2-way poppet solenoid valves. The outlets of first and second poppet solenoid valves are connected to the A and B load ports, respectively. The A and B ports are respectively connected to the checked port of first and second pilot-operated check valves (POCVs) whose outlets are connected to the tank port T. The pilot ports of the POCVs are cross connected from A to B and from B to A. When the solenoid for the first poppet solenoid valve is energized, the first poppet solenoid valve opens, admitting pressure to port A. Pressure is blocked to the tank port by the first POCV. Simultaneously, the pilot pressure from the A-line opens the second POCV, thereby connecting the B port to tank. If power fails, pressure is maintained in the A-line and the B-line remains connected to tank.

Abstract: A rescue tool as incorporated into a portable unit both the tool operating mechanism and the hydraulic power means necessary to provide a self-contained tool. An elongated tool body comprises the rescue tool mechanism and its associated hydraulic actuator unit, an air/oil intensifier pump for driving the hydraulic actuator unit, the control valves for the pump, and an air valve for actuating the hydraulic control valves to their control positions, whereby the only hose connection to the portable unit is a single air hose for supplying high pressure air.