Hydraulic cushion for dies

Claim 1

IN A CRANK TYPE PRESS WHEREIN THE PRESS RAM DECELERATES AS ITS APPROACHES ITS CLOSED POSITION AND A DIE PAD IS ENGAGED BY THE WORK UPON THE CLOSING OF THE PRESS RAM A HYDRAULIC CUSHION ARRANGED TO RESIST MOVEMENT OF SAID DIE PAD UPON CLOSING OF THE PRESS RAM AND TO RETURN THE DIE PAD TO ITS EXTENDED POSITION UPON OPENING OF THE PRESS RAM, SAID HYDRAULIC CUSHION COMPRISING A HYDRAULIC SYSTEM WHICH INCLUDES A HYDRAULIC WORK CYLINDER AND PISTON REACTING AGAINST SAID DIE PAD AND DISCHARGING HYDRAULIC FLUID THEREFROM AT A DECREASING RATE AT THE RAM CLOSES, A TANK OF HYDRAULIC FLUID UNDER RELATIVELY LOW PRESSURE, HYDRAULIC FLUID FLOW AND PRESSURE TRANSMITTING CONNECTIONS BETWEEN SAID TANK AND CYLINDER FOR SUPPLYING HYDRAULIC FLUID TO THE LATTER UNDER TANK PRESURE, AND NORMALLY CLOSED PRESSURE RELIEF MEANS DISPOSED IN SAID HYDRAULIC FLUID FLOW AND PRESSURE TRANSMITTING CONNECTIONS BETWEEN SAID TANK AND WORK CYLINDER SO AS TO CREATE A VARYING RESISTANCE TO THE DISCHARGE OF HYDRAULIC FLUID FROM SAID WORK CYLINDER UPON AND DURING CLOSING THE FLUID FROM SAID WORK IMPROVEMENT WHEREIN SAID PRESSURE RELIEF MEANS COMPRISES A PRESURE RELIEF ORIFICE FORMING A PART OF SAID FLUID FLOW CONNECTIONS AND THROUGH WHICH HYDRAULIC FLUID IS DIS CHARGED FROM SAID WORK CYLINDER, AND HYDRAULIC PRESSURE OPERATED VALVE MEANS COOPERABLE WTHE SAID ORIFICE AND MOVABLE IN RESPONSE TO THE DISCHARGE OF HYDRAULIC PRESSURE FROM THE WORK CYLINDER TO OPEN SAID ORIFICE TO THE MAXIMUM POSITION FOR WHICH IT IS SET DURING THE RELATIVELY FAST CLOSING MOVEMENT OF THE PRESS RAM TO PROVIDE A RELATIVELY HIGH PRESSURE RESISTANCE TO THE RESULTING DISCHARGE OF HYDRAULIC FLUID FROM SAID WORK CYLINDER, SAID ORIFICE BEING NARROW IN WIDTH AND ELONGATED IN THE DIRECTION OF MOVEMENT OF SAID VALVE MEANS, SAID PRESSURE OPERATED VALVE MEANS BEING MOVABLE IN RESPONSE TO A DECREASING RATE OF DISCHARGE OF HYDRAULIC FLUID FROM THE WORK CYLINDER DURING THE SUCCEEDING RELATIVELY SLOWER CLOSING MOVEMENT OF THE PRESS RAM SO AS TO REDUCE THE EXTENT OF OPENING OF SAID ORIFICE AND THE RESISTANCE TO THE RESULTING DISCHARGE OF HYDRAULIC FLUID FROM SAID WORK CYLINDER AS THE PRESS RAM MOVES TO ITS CLOSED POSITION.