Long travel hydraulic cushion device

Claim 1

IN A HYDRAULIC CUSHION DEVICE COMPRISING A CYLINDER HAVING A BORE, A FIRST BASE PLATE FIXED TO ONE END OF SAID CYLINDER, AN INTERMEDIATE CYLINDER BEAD FIXED WITHIN SAID CYLINDER BORE INWARDLY OF THE OPEN END OF SAID CYLINDER, SAID INTERMEDIATE CYLINDER HEAD DEFINING ON ONE SIDE THEREOF WITH SAID FIRST BASE PLATE A HYDRAULIC FLUID-FILLED BORE AND ON THE OPPOSITE SIDE THEREOF ADJACENT SAID OPEN END A FLEXIBLE BOOLT RESERVOIR CHAMBER, AN AXIAL OPENING IN SAID INTERMEDIATE CYLINDER HEAD, A PISTON HEAD MEANS RECIPROCABLE WITHIN SAID BORE AND HAVING A HYDRAULIC FLUID ORIFICE MEANS FORMED THEREIN, SAID PISTON HEAD MEANS DEFINING WITHIN SAID BORE A HIGH PRESSURE CHAMBER WITH SAID FIRST BASE PLATE MEANS AND A LOW PRESSURE CHAMBER WITH SAID INTERMEDIATE CYLINDER HEAD AND BEING MOVABLE FROM A NEUTRAL POSITION AND A CONTRACTED POSITION, A TUBULAR PISTON ROD EXTENDING OUTWARDLY THROUGH SAID INTERMEDIATE CYLINDER HEAD AXIAL ORIFICE, A FLEXIBLE BOOT RESERVOIR CONNECTED BETWEEN SAID INTERMEDIATE CYLINDER HEAD AND SAID OUTWARDLY EXTENDING END OF SAID TUBULAR PISTON ROD, SAID FLEXIBLE BOOT RESERVOIR HAVING FLUID COMMUNICATION WITH SAID CYLINDER BORE, A SECOND BASE PLATE FIXED TO THE OTHER END OF SAID TUBULAR PISTON HEAD AND RETURN SPRING MEANS DISPOSED BETWEEN SAID FIRST AND SECOND BASE PLATES FOR RETURNING SAID PISTON HEAD FROM SAID CONTRACTED POSITION TO SAID NEUTRAL POSITION; THE IMPROVEMENT WHEREIN SAID PISTON HEAD MEANS COMPRISES A PISTON HEAD HAVING AN OUTER DIAMETER LESS THAN THE DIAMETER OF SAID CYLINDER BORE SO AS TO DEFINE AN ANNULAR SPACE, REVERSE FLUID FLOW PASSAGE MEANS EXTENDING THROUGH SAID PISTON HEAD FROM SAID OUTER CIRCUMFERENCE TO THE HIGH PRESSURE FACE THEREOF, AND RING MEANS MOUNTED ON SAID OUTER CIRCUMFERENCE SPANNING SAID ANNULAR SPACE, SAID RING MEANS BEING LENGTHWISE SLIDABLE ON SAID PISTON BETWEEN A POSITION CUTTING OFF HYDRAULIC FLUID FLOW THROUGH SAID REVERSE FLOW PASSAGES DURING THE TRAVEL TO SAID CONTRACTED POSITION AND A POSITION PERMITTING HYDRAULIC FLUID FLOW THROUGH SAID REVERSE FLOW PASSAGES DURING THE RETURN TO SAID NEUTRAL POSITION.