Hydraulic draft gear

Claim 1

A DOUBLE ACTING HYDRAULIC CUSHION DEVICE FOR A DRAFT GEAR ARRANGEMENT, SAID HYDRAULIC DEVICE COMPRISING A HYDRAULIC FLUID FILLED HOUSING FORMING A RESERVOIR, A HYDRAULIC FLUID FILLED CYLINDER DISPOSED WITHIN SAID RESERVOIR, ORIFICE MEANS FORMED IN SAID CYLINDER PROVIDING COMMUNICATION BETWEEN THE BORE OF SAID CYLINDER AND SAID RESERVOIR, A PISTON HEAD MEANS RECIPROCABLE WITHIN SAID CYLINDER BETWEEN A NEUTRAL POSITION ADJACENT ONE END OF SAID CYLINDER TO A BUFF POSITION ADJACENT THE OTHER END OF SAID CYLINDER, PRESSURE RELIEF PASSAGE MEANS THROUGH SAID PISTON HEAD, SAID PRESSURE RELIEF PASSAGE MEANS INCLUDING A GROOVE FORMED ON THE PISTON HEAD SIDE FACING SAID ONE END OF SAID CYLINDER, VALVE SEAT MEANS PARTIALLY DISPOSED WITHIN SAID GROOVE AND INCLUDING A PLURALITY OF CONICAL OPENING COMMUNICATING WITH AN ANNULAR ORIFICE, VALVE MEANS SEATABLE OVER SAID PRESSURE RELIEF PASSAGES, BELLEVILLE SPRING MEANS URGING SAID VALVE MEANS INTO SEATING RELATIONSHIP OVERLYING SAID PRESSURE RELIEF PASSAGE MEANS, SAID BELLEVILLE SPRING MEANS BEING YIELDABLE AT A PRESELECTED PRESSURE FORCE OF THE HYDRAULIC FLUID THROUGH SAID PASSAGE MEANS AND BEING FULLY DEFLECTED UPON A SMALL INCREASE IN THE PRESSURE FORCE TO UNSEAT SAID VALVE MEANS FROM OVERLYING RELATION WITH SAID PRESSURE RELIEF PASSAGE MEANS.