ACCELERATING DEVICE FOR MECHANICAL PRESS

PURPOSE:To improve the effect of an accelerating device by controlling the interval between a pair of plates by a stopper provided between them, then, providing a device to relieve the hydraulic pressure between a large and a small piston in a hydraulic piston type accelerating device. CONSTITUTION:The stopper 13 to control the interval between an upper and a lower plate 11, 12 is provided at a position wherein a billet 2 has been finished on the lower plate 12 and an intensifier 14 is prepared as a hydraulic pressure relieving device. When the crankshaft 4 of a mechanical press 1 rotates, a slide 7 is lowered, the large piston 8 of the speed increaser 3 is pressed down and the small piston 10 is accelerated and lowered to press and work the billet 2 between the plates 11, 12. When operation comes to an end, the interval between the plates 11, 12 is controlled but the slide 7 continues to press the piston 8. Thus, the pressure between the pistons 8, 10 is raised, the device 14 is operated and the hydraulic pressure is relieved to the tank 21. Consequently, before the speed of the slide 7 is lowered, the acceleratray device 3 is operated to obtain a fast working speed.