Hydraulic cylinder

Claim 1

A FLUID PRESSURE ACTUATOR AND LOCKING DEVICE COMPRISING: A TUBULAR CASING HAVING FIRST AND SECOND END CLOSURES RESPECTIVELY ATTACHED TO OPPOSITE ENDS THEREOF, SAID FIRST END CLOSURE HAVING AN APERTURE FORMED THEREIN, SAID CASING HAVING A FLUID PRESSURE PORT AT EACH END THEREOF; A PROJECTION DISPOSED WITHIN SAID CASING AND CONNECTED AT ONE END TO SAID SECOND END CLOSURE, AT LEAST ONE SURFACE OF SAID PROJECTION BEING CONVERGENT WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID CASING IN THE DIRECTION OF SAID FIRST END CLOSURE; A TUBULAR SHELL SLIDABLY DISPOSED WITHIN SAID CASING, SAID SHELL HAVING FIRST AND SECOND END WALLS WHICH ARE RESPECTIVELY ATTACHED TO OPPOSITE ENDS THEREOF AND EACH OF WHICH IS PROVIDED WITH AN APERTURE THROUGH WHICH SAID PROJECTION EXTENDS, SAID FIRST END WALL FACING SAID FIRST END CLOSURE AND HAVING A VENT PASSAGE FORMED THEREIN; A PISTON SLIDABLY DISPOSED WITHIN SAID SHELL, SAID PISTON HAVING AN OPENING FORMED THEREIN WHICH IS SUBSTANTIALLY COAXIAL WITH SAID CASING AND THROUGH WHICH SAID PROJECTION EXTENDS, THE PORTION OF THE WALL OF SAID OPENING THAT FACES SAID CONVERGENT SURFACE OF SAID PROJECTION ALSO BEING CONVERGENT WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID CASING IN THE DIRECTION OF SAID FIRST END CLOSURE, SAID PISTON HAVING A VENT PASSAGE FORMED THEREIN; A TUBULAR SHAFT SLIDABLY DISPOSED IN SAID APERTURES IN SAID FIRST END WALL AND SAID FIRST END CLOSURE RESPECTIVELY, SAID SHAFT BEING CLOSED AT ONE END AND CONNECTED AT THE OTHER END TO SAID PISTON SO THAT THE INTERIOR THEREOF COMMUNICATES WITH SAID OPENING IN SAID PISTON; AT LEAST ONE LOCKING WEDGE DISPOSED WITHIN SAID SHELL, SAID LOCKING WEDGE HAVIG AN INNER SURFACE WHICH IS DISPOSED ADJACENT SAID CONVERGENT SURFACE OF SAID PROJECTION AND AN OUTER SURFACE WHICH IS CONVERGENT WITH RESPECT TO THE LONGITUDINAL AXIS OF SAID CASING IN THE DIRECTION OF SAID FIRST END CLOSURE; MEANS CONNECTED TO SAID SHELL AND ADAPTED TO MAINTAIN SAID LOCKING WEDGE A PREDETERMINED DISTANCE FROM SAID SECOND END WALL WHILE PERMITTING IT TO MOVE IN A DIRECTION SUBSTANTIALLY PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID CASING; FIRST VALVE MEANS MOUNTED ON SAID FIRST END WALL AND ADAPTED TO CLOSE SAID VENT PASSAGE THEREIN WHEN FLUID PRESSURE IS ADMITTED INTO SAID CASING BETWEEN SAID FIRST END WALL AND SAID FIRST END CLOSURE; AND SECOND VALVE MEANS MOUNTED ON SAID PISTON AND ADAPTED TO CLOSE SAID VENT PASSAGE THEREIN WHEN FLUID PRESSURE IS ADMITTED INTO SAID CASING BETWEEN SAID PISTON AND SAID SECOND END CLOSURE.