Locking device for a fluid operated rod

Claim 1

IN A PRESSURE FLUID OPERATED DEVICE INCLUDING A WORKING CYLINDER, A WORKING PISTON MOVABLE IN SAID CYLINDER, A PISTON ROD ASSOCIATED WITH SAID PISTON AND EXTENDING FROM THE CYLINDER AND MEANS FOR SUPPLYING PRESSURE FLUID TO END PORTIONS OF SAID CYLINDER, THE PROVISION OF MEANS FOR MECHANICALLY RELEASABLY LOCKING SAID PISTON ROD AND PISTON AT THE END OF A WORKING STROKE WITHOUT RELIANCE UPON MAINTENANCE OF PRESSURE FLUID IN SAID CYLINDER, COMPRISING: AN ANNULAR RECESS FORMED IN THE CYLINDER, SAID RECESS INCLUDING A STOP SHOULDER; SEGMENTED LOCKING ELEMENTS CARRIED BY THE PISTON ROD, AND RADIALLY EXPANDABLE INTO OPERATIVE ENGAGEMENT WITH SAID STOP SHOULDER, SAID LOCKING ELEMENTS HAVING A FRUSTO-CONICAL INNER BORE; A LOCKING CONE CARRIED BY THE PISTON ROD ADJACENT THE PISTON AND COOPERABLE WITH SAID FRUSTO-CONICAL INNER BORE TO RADIALLY EXPAND SAID LOCKING ELEMENTS INTO ENGAGEMENT WITH SAID STOP SHOULDER FOR RELEASABLY LOCKING SAID PISTON ROD AT THE END OF ITS WORKING STROKE; SPRING MEANS ADJACENT SAID LOCKING CONE TO BIAS SAID LOCKING CONE INTO OPERABLE ENGAGEMENT WITH SAID LOCKING ELEMENTS; AND A SECOND SPRING MEANS OPERATING ON SAID PISTON AND SAID ROD FOR BIASING THE PISTON AND THE ROD RELATIVE TO EACH OTHER WHEN SAID LOCKING ELEMENTS ARE IN ENGAGEMENT WITH SAID STOP SHOULDER.