GB357601A - Improvements in and relating to presses - Google Patents

Abstract

357,601. Mechanical presses. JACKSON, L. MELLERSH-, 28, Southampton Buildings, London. -(Terkelsen, A.; 12, Bradford Road, Newton, Massachusetts, U.S.A.) May 19, 1930, No. 15397. [Class 87 (ii).] A press comprises a ram and a resiliently supported bed, said ram being controlled by manually adjustable means coacting with means for automatically controlling its movement in dependence upon the amount of pressure exerted, the ram and bed being retained in position when their relative movement is stopped. The bed 15 is secured by adjustable nuts 19 on four posts 18 which are resiliently supported by springs 22 bearing against the adjustable collars 24. The ram 16 is carried by the double rack 27 which is driven by the electric motor M through the train of gears 28, 40. The motor M is a three-phase alternating current motor supplied by feed lines L1, L2, L3 and controlled by a reversing switch R which is provided with two triple-pole, magnetically operated, contactors a, b. The contactor a comprises a pivoted member carrying an armature 110 which co-operates with the coil 61 to close the switch. An electric interlock e is provided to close the operating circuit. The contactors a, b are mechanically interlocked by the bar 117. The motor circuit is controlled by " up," " down," and " stop " switches 80, 81, 82 and also by two automatic limit switches A, B. By pressing the " up " switch 80 the circuit shown in full lines, Fig. 3, is closed and the coil 61 energized to close the contactor a and start the motor M. The interlock e is also closed to keep the coil 61 energized. When either the limit switch A or the " stop " switch 82 are opened the contactor a and interlock e will open and stop the motor. The " down " switch 81 closes the circuit shown in dot and dash lines, Fig. 3, and reverses the motor by means of the contactor b. The armature shaft 42 of the motor is provided with a solenoid brake 54 which is applied when the motor circuit is opened. The limit switch B has a trip arm 26 which is engaged by a lug 43, adjustably carried on the ram 16, when the ram descends. The trip arm 26 of the switch A is engaged by an adjustable slide 47 carried on one of the posts 18 so that the switch A is opened when the bed yields. A scale 49 may be provided to regulate the limiting pressure. The switch A may also be opened by the lug 43 contacting with a projection 53 upon excessive upward movement of the ram. A pressure indicator is provided, comprising a dial 120 carried by the post 18 over which moves a pointer 123 which is rotated by the rack and pinion 124.