Patent GB-860932-A (GB)
Title: Shear machine with adjustable ram
IPC: B23D35/00
Filed: 1958-09-04
Abstract: 860,932. Shearing. PACIFIC INDUSTRIAL MANUFACTURING CO. Sept. 4, 1958 [Dec. 24, 1957], No. 28412/58. Class 83 (4). In a machine, e.g. a shearing machine operated by two cylinders mounted one at each end of the reciprocating ram, the cylinders are normally supplied with liquid from an hydraulic system so that equal piston speeds result but operatorcontrollable means are provided to selectively alter the relative feed rate of liquid for tilting adjustment of the ram in either direction and means are also provided for limiting the tilt. An hydraulicallyoperated shear comprises a frame 1, with spaced side-walls, a work-table 11 carrying a stationary blade 15 and a ram 17 which reciprocates in guides 25 and which carries a blade 19. The ram is actuated by cylinders 33, 35 arranged in series and attached to the side walls. The cylinders each have a piston-rod 40 pivoted to the ram at 36. The work is held prior to shearing by hold-down devices 41 comprising hydraulic cylinders suspended from a fixed beam 43. The solenoid - operated valves of the hydraulic circuit are actuated in sequence on closing a foot switch 231, Fig. 7 (not shown). Solenoidcontrolled relays 227, 237, 205, 217, 235, 201, Fig. 7 (not shown), operate to set up circuits for operation of the ram and hold-downs. Hydraulic fluid is pumped from a reservoir by a main pump, the pressure on the hold-downs being maintained after initial actuation by an auxiliary pump. While the foot-switch 231 is closed the ram 17 will cycle up and down, the stroke being controlled by stops 95, 117 adjustable on a scale 91 and which operate associated switches. An inch switch, if open, causes the ram to remain in the lower position. An adjustable depth stop 105 and switch 107 is also provided to prevent the piston 39 bottoming in cylinder 33. The rake-angle of the blade 19 is adjustable up or down from a normal position indicated by the centre of a scale 169, Fig. 6. On rotation of an adjusting wheel 155 a spring-biased arm 141 of an actuating bar 137 is pivoted about a point 139 by a cable 158 and according to the direction of rotation one or other of switches 127, 129 is closed. The lower end of the actuating bar at the same time may operate either one of emergency stop limit switches 183, 181, should the tilting of the ram become excessive; the lower end of the actuating bar 137 is arranged to travel further in either direction before actuating the switches than the upper end. The switches 181, 183 actuate a solenoidcontrolled emergency stop valve which, when opened, causes the main pump to idle. The circuits may be re-established by depressing a button switch. The adjustment to increase the blade tilt is effected by actuation of the switch 129, liquid being pumped through an " up " valve 59, Fig. 7 (not shown), to the underside of the piston in the.cylinder 33, the liquid by-passing cylinder 39 through a solenoidoperated valve 265 to the reservoir 47. The blade 19 will therefore tilt effectively about its lower end. Likewise the blade tilt is decreased when the switch 127 operates and liquid passes to both ends of the cylinder 33, since the solenoid-operated valve 271 is then open. Differential thrust due to differing areas of the upper and lower sides of the piston cause the piston to move down and decrease the tilt of the blade. While making the blade tilt adjustment a push-button is held depressed to maintain the regional set-up of the hydraulic circuit.