Importance

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Abstract

A new breed of die cylinders operating at 1000-5000 psig. working fluid pressures and adaptable for use individually or by manifolding with punch presses to cushion dies can be operated with maximum rated pressure force against a force which a ram develops in one direction and in the opposite direction with partial pressure force which the die cylinders exert when force balanced. The following is accomplished by loading a piston underside by the same working fluid pressure when the piston bottoms inside a cylinder housing at the end of the ram induced stroke enabling an instant high pressure surge of fluid, be it Nitrogen gas or other working fluid, to enter the piston underside provided with a piston rod and exert a resistance force proportional to the net free area exposed thereto thereby providing force balanced cylinder operation. The die cylinder capacity during the cycle of rod extension will be controlled by the size of the piston rod while the die cylinder capacity during the cycle of rod withdrawal under ram load will be controlled by the size of the piston face opposite to that provided with the piston rod. The structure includes provisions for discharge of the working fluid from the piston underside at the end of the cylinder stroke with the rod extended, and for generating a vacuum behind the piston during rod withdrawal until the ram stroke is completed, and vice-versa, providing for directional braking of the die cylinder operation analogous to the operation of die cylinders with built-in time delays, but, at considerably reduced cost to construct and to operate die cylinders of this general type.

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First Claim