GB300687A - Improvements in presses for drawing sheet metal and the like - Google Patents

Abstract

300,687. Fitzpatrick, H. D., (Marquette Tool & Manufacturing Co.). Aug. 18, 1927. Cupping. - In a drawing-press a reciprocating die 27 cooperates with a fixed die 18. A draw-die 26 is supported by air or other fluid pressure from a tank 36 acting on a column of liquid 50. The die 27 is reciprocated by a crank 13 and the member 25 is supported by a plunger 22 in a cylinder 21 connected by a pipe 30 with a spring-loaded valve 33 and by a further pipe to the tank 36. A pipe 41 forms a bye-pass round the valve 33 and contains a flap valve 42 and a valve 43 controlled from the crank-shaft. The tank is put under air pressure by a pipe 38. On the downstroke of the die 27 the member 26 descends and the valve 33 lifts. The member 26 is raised when the valve 43 is opened. Resilient bevelled pins 28 strip the workpiece from the die 27. An ejector 55 actuated by a pawl 64 from the cross-head of the press discharges the articles down a shoot 53. In a modification, the valves 42, 33 are connected directly with the cylinder 21 and an air receiver is fitted to the valve 42. In a further modification, the invention is applied to a press in which a double drawing operation is performed in a single-acting press. The invention is also applied to a double-acting press.