Long travel hydraulic cushion device

Claim 1

A HYDRAULIC CUSHION DEVICE COMPRISING A HYDRAULIC FLUID-FILLED CYLINDER HAVING A CLOSED END AND AN OPEN END, A PISTON HEAD ASSEMBLY RECIPROCABLE WITHIN SAID CYLINDER FROM A NEUTRAL POSITION BETWEEN SAID OPEN END AND SAID CLOSED END OF SAID CYLINDER AND A CONTRACTED POSITION ADJACENT SAID CLOSED END, SAID PISTON HEAD ASSEMBLY DEFINING A HIGH PRESSURE CHAMBER ADJACENT THE CLOSED END OF SAID CYLINDER AND A LOW PRESSURE CHAMBER ADJACENT THE OPEN END OF SAID CYLINDER, A TUBULAR PISTON ROD FASTENED AT ONE END TO SAID PISTON HEAD ASSEMBLY, SAID TUBULAR PISTON ROD HAVING THE OTHER OF SAID ENDS EXTENDING OUTWARDLY OF SAID OPEN END OF SAID CYLINDER, AN EXPANDABLE HYDRAULIC FLUID RECEIVING RESERVOIR COMMUNICATING WITH SAID LOW PRESSURE CHAMBER AND CONNECTED BETWEEN SAID CYLINDER AND SAID PISTON ROD FOR CLOSING-OFF SAID OPEN END OF SAID CYLINDER, SPRING MEANS FOR RETURNING SAID PISTON HEAD ASSEMBLY FROM SAID CONTRACTED POSITION TO SAID NEUTRAL POSITION, SAID PISTON HEAD ASSEMBLY INCLUDING AN ORIFICE PLATE FIXED TO SAID ONE END OF SAID TUBULAR PISTON ROD AND HAVING AN ORIFICE AXIALLY ALIGNED WITH THE BORE OF SAID TUBULAR PISTON ROD, A METERING PIN FIXED TO SAID CLOSED END OF SAID CYLINDER AND PROJECTING THROUGH SAID ORIFICE TO PROVIDE A GRADUALLY DIMINISHING EFFECTIVE ORIFICE AREA AS SAID PISTON HEAD ASSEMBLY MOVES TOWARD SAID CONTRACTED POSITION, SAID PISTION HEAD ASSEMBLY FURTHER INCLUDING A SLIDE HEAD LONGITUDINALLY SLIDABLE MOUNTED ON SAID ONE END OF SAID TUBULAR PISTON ROD FOR MOVEMENT BETWEEN A POSITION ABUTTING SAID ORIFICE PLATE MEMBER WHEN SAID PISTON HEAD ASSEMBLY MOVES TOWARD SAID CONTRACTED POSITION AND A POSITION EXTENDED FROM SAID ORIFICE PLATE WHEN SAID PISTON HEAD MOVES TO SAID NEUTRAL POSITION, SAID SLIDE HEAD HAVING FLUID PASSAGE MEANS BY-PASSING SAID ORIFICE IN SAID ORIFICE MEMBER WHEN SAID SLIDE HEAD IS IN SAID EXTENDED POSITION TO PROVIDE DIRECT HYDRAULIC FLUID COMMUNICATION BETWEEN SAID LOW PRESSURE AND HIGH PRESSURE CHAMBERS.