GB476573A - Improvements in forging presses - Google Patents

Abstract

476,573. Forging - press. EVANS, W. E. (Hydraulik Ges.) June 9, 1936, No. 16131. [Class 83 (iv)] [Also in Group XXIX] In an hydraulically-operated forging- press of the pump piston type with fluid control, electrically actuated drive to pump and variable pressure between pump and working cylinder, the return stroke cylinders are under the constant pressure of an accumulator connected with the pressure pipe between the working plunger and pump plunger through hand-operated valves. As shown, the working cylinder 1 is connected by a pipe 9 with the pump cylinder 10 having a plunger 12 driven from a shaft 11, which also operates a plunger 15 of a cylinder 16 connected by a pipe 17 to a valve casing 22. A valve casing 31 with a non-return valve 32 has handoperated valves 33, 34, 35 and is connected at 30 to the pipe 9, which is connected by a pipe 37 to an accumulator and by a pipe 38 to a tank 24. An accumulator 20 is connected by a pipe 41 to the return stroke cylinders 5, the pipe 41 being also connected to the pipe 37. A spring pressed plunger 27 works in a cylinder 26 connected by a pipe 25 to the accumulator and is attached to a valve 21. A non-return valve 19 controls connection to the accumulator. With the valve 33 closed, the piston 2 remains uniform in stroke. With the valves 33, 34 open and the valve 35 closed, water flows into the pipe 9 for lowering the press tool on to the work. Thereupon, when the driving shaft operates by starting a motor or throwing in a clutch in the driving mechanism, the piston 2 makes a working stroke regulated by the position of the throttle valve 33 in conjunction with the valves 34, 35.