Abstract: In a double-acting hydraulic press: an outer press ram having a cylinder formed therewithin for the piston of an inner press ram, the inner and outer ram cylinders in communication with one another and the rams being subject to a common hydraulic actuating means, each ram carrying a separate and distinct tool at its forward face, and means controllably feeding pressurized hydraulic fluid to an intermediate section of said inner ram cylinder, whereby to control the effective hydraulic force applied to said inner ram and the tool thereof.

Abstract: In a hydraulic forging press having one or a plurality of press rams actuated reciprocatively through working oil by reciprocating motion of pump ram given by mechanical driving means, a closed forging press being provided with one or a plurality of punch rams disposed in a position to communize said working oil with said press ram and perform double action with said press ram, and actuated through said working oil by reciprocating motion of said pump ram.

Abstract: This case discloses a forging press having a pump ram inserted into the upper part of a cylinder within a frame, a press ram into the lower part thereof, and a cavity filled with working oil provided between both parts of the cylinder for transmitting the mechanically given reciprocating motion of the pump ram to the press ram by the working oil, said forging press comprising a stopper provided outside the frame for mechanically controlling the upper limit position in reciprocating motion of the press ram and enabling an adjustment of the position where the stopper and corresponding portion of the press ram come into contact with each other, from outside during operating the press, wherein a controllable check valve for open-and-close operation is provided in the middle of oil passage which communicates with working oil supply source and working oil in the cylinder, for feeding or discharging oil into or from the supply source therethrough according to shortage or excess of oil quantity in the cylinder result