GB835388A - An arrangement for actuating shears and similar machines and for various types of presses - Google Patents

Abstract

835,388. Metal-working presses; shearing. ETABLISSEMENTS GRIMAR. Aug. 6, 1958 [Oct. 11, 1957], No. 25190/58. Class 83 (4). Actuating mechanism for the tool holder 5 of a metal working press.or a shears comprises two parallel toggle linkages 11a, 11b, connected respectively at 15a, 15b, to the tool holder and whose centre pivots 21a, 21b are connected to opposite sides of a double-acting hydraulic piston 22 for actuation thereby. A shears has a fixed blade 9 on a stationary platen 3 and a moving blade 8 on the tool holder 5. An hydraulically operated hold-down 45 is biased to open position by springs 46. The toggle links are pivoted at 12a, 12b to a fixed support plate 4 and at 14a, 14b to bell-cranks 13a, 13b. The latter have ball ends 15a, 15b seating in supports 16a, 16b secured to the tool holder 5 and are pivoted at 18a, 18b to links 19a, 19b mounted on stationary pivots 20. Hydraulic fluid from a reservoir 33 is supplied by a pump 31 driven by an electric motor 36, to a solenoid-actuated reversing valve 30 which first distributes the fluid to the cylinders of the hold-down 45 and also to the right-hand side of piston 22 to effect the shearing stroke and then automatically to the left-hand side to effect a quick return stroke. An electrical control circuit is described, Figs. 4, 5 (not shown). In another embodiment, Fig. 6 (not shown), the positions of the ball ends 15a, 15b are adjustable manually or by a motor. The working stroke may be performed on the upstroke.