Fluid motor operator having relatively movable working members

Claim 1

AN OPERATOR DEVICE FOR MOVING AN OPERATIVE MEANS OF A VALVE BETWEEN OPEN AND CLOSED POSITIONS COMPRISING: A HOUSING HAVING MEANS FOR CONNECTION TO A VALVE AND PROVIDED WITH A LONGITUDINAL BORE; AN OPERATOR ROD EXTENDING THROUGH SAID BORE OF SAID HOUSING AND LONGITUDINALLY MOVABLE THEREIN, SAID OPERATOR ROD HAVING MEANS AT ONE END CONNECTABLE TO OPERATIVE MEANS OF A VALVE, SAID OPERATOR ROD HAVING PISTON MEANS SEALINGLY ENGAGEABLE WITH SAID HOUSING AND DIVIDING SAID BORE INTO A FIRST CHAMBER ON ONE END OF SAID PISTON MEANS AND A SECOND CHAMBER ON THE OTHER END OF SAID PISTON MEANS; MEANS PROVIDING A BYPASS FLOW PASSAGE COMMUNICATING WITH SAID CHAMBERS ON OPPOSITE ENDS OF SAID PISTON MEANS, SAID OPERATOR DEVICE HAVING MEANS FOR ADMITTING MOTIVE FLUID PRESSURE TO SAID FIRST CHAMBER; MEANS ASSOCIATED WITH SAID BYPASS FLOW PASSAGE TO EFFECT A REDUCTION OF FLUID PRESSURE IN SAID SECOND CHAMBER RELATIVE TO SAID FIRST CHAMBER, SAID BORE OF HOUSING HAVING ONE LONGITUDINAL PORTION OF REDUCED DIAMETER AND A SECOND LONGITUDINAL PORTION OF ENLARGED DIAMETER, SAID PISTON MEANS INCLUDING A MAIN PISTON MOVABLE IN LONGITUDINAL PORTION OF REDUCED DIAMETER AND AN AUXILIARY PISTON MOVABLE IN SAID PORTION OF ENLARGED DIAMETER OF SAID BORE; COENGAGEABLE . MEANS ON SAID PISTONS LIMITING MOVEMENT OF SAID MAIN PISTON RELATIVE TO SAID AUXILIARY PISTON UPON MOVEMENT OF SAID OPERATOR ROD AND MAIN PISTON FROM ONE EXTREME LONGITUDINAL PORTION IN SAID HOUSING A PREDETERMINED DISTANCE IN ONE PORTION IN SAID HOUSING, THE OPERATOR ROD BEING ADAPTED TO HOLD OPERATIVE MEANS OF A VALVE IN OPEN POSITION WHEN IN SAID ONE EXTREME POSITION AND BEING ADAPTED TO MOVE OPERATIVE MEANS OF A VALVE FROM OPEN TOWARD CLOSED POSITION DURING MOVEMENT THEREOF IN SAID ONE DIRECTION, SAID HOUSING AND SAID AUXILIARY PISTON HAVING COENGAGEABLE MEANS LIMITING MOVEMENT OF SAID AUXILIARY PISTON IN SAID BORE IN A SECOND DIRECTION OPPOSITE TO SAID ONE DIRECTION UPON MOVEMENT OF SAID AUXILIARY PISTON AND SAID OPERATOR ROD A PREDETERMINED DISTANCE FROM A SECOND EXTREME POSITION OF THE OPERATOR ROD WHEREIN THE OPERATOR ROD IS ADAPTED TO HOLD THE OPERATIVE MEANS OF A VALVE IN CLOSED POSITION; AND MEANS SEALING BETWEEN SAID PISTONS WHEN SAID MAIN PISTON IS ENGAGED WITH SAID AUXILIARY PISTON, SAID AUXILIARY PISTON BEING OF GREATER DIAMETER THAN SAID MAIN PISTON.