GB970080A - Improvements in or relating to drawing arrangements for workpiece-drawing presses - Google Patents

Abstract

970,080. Cupping. E. SCHWARZ. April 16, 1962 [April 28, 1961], No.14616/62. Heading B3Q. A deep drawing press comprises a two-part fluid pressure drawing cylinder, in each part of which a piston is provided, the cylinder parts being connected together, without valves, by a pipe, the piston in one cylinder part being in operative connection with a blank holder for carrying the workpiece being drawn, and the piston in the other cylinder part being in cooperation with a pneumatic or spring cushioning device, the said one cylinder part being received by an intermediate plate provided on a table of the press beneath a tool base plate thereof. In an embodiment the press comprises a base plate 12, a drawing die 13, a blank holder 14 supported on studs 15 attached to an hydraulic piston 19 working in a cylinder 18 accommodated in an intermediate plate 17 resting on the table 11 of the press. The cylinder 18 is connected to a second cylinder 21 by a pipe 20. The piston 22 of the second cylinder has a non-return valve 24 which is actuated by a needle 25 to vent the cylinder as the piston approaches the end of its stroke. As the deep drawing operation progresses the piston 22 acts through studs 26 on a counter plate 27 of a cushioning device comprising a spring 28 wound around a bolt 29 the spring pressure being adjusted by means of nuts 30. In the embodiment of Fig. 2 a pneumatic cushioning device is used comprising a cylinder 31 coupled by means of a piston rod 32 to the end plate 23 of the second cylinder 21. Compressed air is supplied to the piston 33 in the . cylinder 31 through a conduit 34. The cushioning studs 26 act on the end face of the cylinder 31.