GB1200772A - Hydraulic thrusting device - Google Patents

Abstract

1,200,772. Hydraulic presses. P. E. ASHTON. 19 Oct., 1967 [24 Oct., 1966], No. 47595/67. Heading B5F. [Also in Division B3] An hydraulic device such as a press e.g. for rivet heading, staking or marking, includes a pump 31 for feeding fluid under pressure from a reservoir 89 to a movable ram 16, the pump being carried by and movable with the ram, and actuating means operated manually for moving the ram into engagement with a workpiece and for thereafter actuating the pump to supply fluid under pressure to the ram. In the example shown the actuating means comprises a hand operated lever 17 pivoted at 20 to a bracket 19 and at 70 to a crosshead 46 secured to a piston-rod 38. The lever 17 is releasably connected to the ram 16 through a spring- biased latch pin 76 having a tongue 82 which is bevelled to match the walls of a groove 81 in the ram 16. Downward movement of lever 17 will thus carry ram 16, a piston 23 and pump 31 together in the same direction. During this movement fluid is drawn from the reservoir 89 through a check valve 29 and into cylinder 22 above piston 23. When the ram 16 meets an obstruction the latch pin 76 will be forced out of groove 81 and will drop into a slot 72 in ram 16 to allow free operation of the parts involved. Continued movement of lever 17 will bring a bushing 51 (Fig. 4), into sealing engagement with an 0-ring 50 carried by an annular piston 47. Downward movement of bushing 51 and piston 47 will force fluid through ports 36 into an annulus 42 and on into cylinder 22 to apply hydraulic pressure to piston 23 and ram 16. At the same time fluid is being drawn past a ball valve 57 into a barrel 32. On reversing the motion of lever 17 piston-rod 38 will move bushing 51 away from ring 50 and allow a cruciform washer 52 carried by rod 38 to engage piston 47 and carry it upwards. Fluid in barrel 32 will thus pass to the underside of piston 47 through a central passage 48 and become available for displacement into cylinder 22 upon further reciprocation of lever 17. To release the ram and raise it, lever 17 is moved upwardly to cause the tongue 82 to re-enter the groove 81, the tip of piston-rod 38 unseating valve 57. In a simplified embodiment (not shown) the valve unit 55 is omitted, giving a short single stroke hydraulic press without locking facility.