Fluid-pressure operated equipment and methods of utilising such equipment

Claim 1

A FLUID-PRESSURE OPERATED RECIPROCATING MOTOR COMPRISING A CYLINDRICAL; A PISTON RECIPROCABLE IN THE CYLINDER; AND CONTROL VALVE MEANS COMPRISING A POPPET VALUE MEMBER WITH TWO SPACED POPPET PORTIONS, TWO OPPOSED SEATINGS BETWEEN WHICH ONE OF SAID POPPET PORTIONS IS MOVABLE AND AGAINST WHICH THAT PORTION ALTERNATIVELY SEATS, TWO FURTHER OPPOSED SEATINGS BETWEEN WHICH THE OTHER OF SAID POPPET PORTIONS IS MOVABLE AND AGAINST WHICH SAID OTHER PORTION ALTERNATIVELY SEATS, BOTH SAID POPPET PORTIONS SEATING TOGETHER TO CONTROL THE INLET AND EXHAUST FLOWS THROUGH THE VALVE MEANS FROM THE CYLINDER AND THE EFFECTIVE CROSSSECTIONAL AREA OF TWO SEATINGS ASSOCIATED WITH ONE SAID ONE PORTION BEING DIFFERENT FROM THE EFFECTIVE CROSS-SECTIONAL AREA OF SAID TWO FURTHER SEATINGS SO THAT IN USE A FORCE DIFFERENTIAL IS PRODUCED WHICH BIASED THE VALVE MEMBER; AND MECHANICAL VALVE OPERATING MEANS INCLUDING A VALVE SPINDLE ON WHICH THE VALVE MEMBER IS SLIDABLY MOUNTED, THE SPINDLE BEING DISPLACEABLY BY THE PISTON TO CHANGE OVER THE VALVE MEMBER, A SPRING THROUGH WHICH A VALVE OPERATING FORCE IS APPLIED TO THE VALVE MEMBER FORM THE SPINDLE AND THE COMPRESION OF WHICH IS SUFFICIENT TO MOVE THE VALVE MEMBER AGAINST SAID BIAS AND TO HOLD THE MEMBER IN A NEW TERMINAL POSITION UNTIL PRESSURE CONDITIONS HAVE BUILT-UP TO PROVIDE THE NECESSARY HOLDING BIAS IN THE OPPOSITE DIRECTION.