Valve means

Claim 1

IN A FULLY HYDRAULIC POWER SYSTEM HAVING A MANUALLY OPERABLE PRESSURE PRODUCING DEVICE ADAPTED TO CONTROL A VARIABLE VOLUME CHAMBER IN THE EVENT OF A POWER FAILURE, A POWER VALVE COMPRISING IN COMBINATION: A VALVE CHAMBER IN SAID PRESSURE PRODUCING DEVICE; A BALL VALVE; A VALVE SEAT WITHIN SAID PRESSURE PRODUCING DEVICE AT ONE END OF SAID VALVE CHAMBER WHICH SEAT IS ADAPTED TO COOPERATE WITH SAID BALL VALVE TO CONTROL A PRESSURIZED FLUID, SAID SEAT HAVING AN AREA OF CONTACT FOR SAID BALL VALVE; A VALVE STEM OPERATIVELY CONNECTED TO SAID BALL VALVE, SAID VALVE STEM HAVING A CROSS-SECTIONAL AREA OF A PORTION IMMEDIATELY BEHIND ITS OPERATIVE CONNECTION WITH SAID BALL VALVE WHICH AREA IS EQUAL TO SAID AREA OF CONTACT OF SAID BALL VALVE WITH SAID VALVE SEAT, SAID VALVE STEM FURTHER HAVING A GROOVED PORTION AND AN INTERNALLY DRILLED PASSED FROM SAID END OPPOSITE THAT OPERATIVELY CONNECTING SAID BALL VALVE THERETO LEADING INWARDLY TO SAID BALL VALVE IMMEDIATELY BEHIND ITS FACE THAT COOPERATES WITH SAID VALVE SEAT; AN ANNULAR FLEXIBLE MEMBER WHOSE INNER SURFACE IS FITTED INTO SAID GROOVE OF SAID VALVE STEM AND WHOSE OUTER DIAMETER IS EQUAL TO SAID VALVE CHAMBER TO LOCATE SAID VALVE STEM INTERNALLY OF SAID VALVE CHAMBER; AND A SPRING MEANS OPERATIVELY CONNECTING SAID ANNULAR FLEXIBLE MEMBER IN SAID VALVE CHAMBER TO SAID PRESSURE PRODUCING DEVICE TO PROJECT SAID VALVE STEM EXTERNALLY OF SAID VALVE CHAMBER INTO THE VARIABLE VOLUME CHAMBER THROUGH AN APPROPRIATELY SIZED OPENING IN SAID PRESSURE PRODUCING DEVICE WITH SAID ANNULAR FLEXIBLE MEMBER OVERLYING SAID OPENING TO FORM A HOLDING MEANS FOR SAID VALVE STEM AND A SEAL FOR SAID OPENING, SAID SPRING MEANS BEING ARRANGED IN SAID VALVE CHAMBER TO BIAS SAID VALVE STEM AND ITS OPERATIVELY CONNECTED BALL VALVE INTO CONTACT WITH SAID VALVE SEAT AT THE OTHER END OF SAID VALVE CHAMBER WHILE HOLDING SAID ANNULAR FLEXIBLE MEMBER TO SAID PRESSURE PRODUCING DEVICE.