Hydraulically controlled punching machine

Claim 1

A HYDRAULICALLY CONTROLLED STAMPING MACHINE COMPRISING A MAIN CYLINDER, A MAIN PISTON HAVING AN UPPER AND A LOWER END AND RECIPROCALLY MOVABLE WITHIN SAID MAIN CYLINDER, A PUNCH RIGIDLY CONNECTED TO THE LOWER END OF SAID MAIN PISTON, AN ANNULAR CHAMBER WITHIN SAID MAIN PISTON EXTENDING REARWARDLY FROM SAID LOWER END AND TERMINATING BELOW SAID UPPER END AT AN UPPER INTERNAL SURFACE OF SAID MAIN PISTON, SAID UPPER INTERNAL SURFACE OF SAID MAIN PISTON HAVING A GIVEN CONTACT AREA FOR CONTACT WITH A FLUID MEDIUM, AN ANNULAR PISTON RECIPROCALLY MOVABLE WITHIN SAID ANNULAR CHAMBER, HOLDER MEANS COOPERABLE WITH THE BOTTOM OF SAID ANNULAR PISTON, FIRST MEANS FOR SUPPLYING A HYDRAULIC FLUID TO SAID MAIN CYLINDER TO DRIVE SAID MAIN PISTON, A COUNTER-PUNCH SUPPORTED IN ALIGNMENT WITH SAID PUNCH, A FURTHER PISTON RIGIDLY CONNECTED TO SAID COUNTER PUNCH, A FURTHER CYLINDER WHEREIN SAID FURTHER PISTON IS RECIPROCALLY MOVABLE, SECOND MEANS FOR SUPPLYING A FLUID MEDIUM UNDER PRESSURE TO SAID ANNULAR CHAMBER AND SAID FURTHER CYLINDER, SAID SECOND MEANS INCLUDING A FIRST CHECK VALVE AND FIRST THROTTLE VALVE MEANS ADAPTED TO COOPERATE WITH SAID ANNULAR CHAMBER AND A SECOND CHECK VALVE AND SECOND THROTTLE MEANS IN REGISTRY WITH SAID FURTHER CYLINDER, SAID RESPECTIVE THROTTLE VALVE MEANS BEING MOVABLE INTO AN OPEN POSITION UNDER THE INFLUENCE OF A CHANGEABLE PRESSURE MAGNITUDE WHICH IN ALL INSTANCES OF SAID OPEN POSITION OF SAID RESPECTIVE THROTTLE VALVE MEANS IS GREATER THAN THE PRESSURE EXERTED BY SAID FLUID MEDIUM SUPPLIED FROM SAID SECOND MEANS, SAID CHANGEABLE PRESSURE MAGNITUDE BEING AT LEAST A FUNCTION OF THE VELOCITY OF MOVEMENT OF SAID MAIN PISTON AND THE GIVEN CONTACT AREA OF SAID UPPER SURFACE, WHEREBY THE RATE OF RETURN FLOW OF SAID FLUID MEDIUM FROM SAID ANNULAR CHAMBER THROUGH SAID FIRST THROTTLE VALVE MEANS IS REGULATED TO THUS INFLUENCE IN A CONTROLLED MANNER OPERATION OF SAID PUNCH AND HOLDER MEANS.