GB847642A - Improvements in or relating to electric circuit controlling apparatus particularly for effecting electric cycles of movement of the work tables of machine tools - Google Patents

Abstract

847,642. Control of several motors. ELLIOTT & CO. Ltd., B., FRYE, C. H., and SELBY, J. Nov. 22, 1956 [Aug. 22, 1955], No. 24126/55. Class 38 (3). [Also in Group XXII] Relates to electrical control apparatus for effecting selected cycles of movement of the work-table of a machine tool wherein relative movement between a number of switches and corresponding dogs takes place in accordance with the movement of the work-table, the switches being adapted to establish electric motor connections for driving the table in a selected cycle of operations. As shown, the apparatus is set for automatic operation by closing contacts AU1, AU2, AU3, AU4, and opening contacts H1, H2, the dogs having been adjusted to appropriate positions. Depression of a push-button TRPB, for example, energizes a quick-traverse-right contactor TRCW whereby a motor QTM drives the table to the right at high speed, and the contactor closes a self-holding contact. If now a dog-operated switch is actuated to open contacts FRS1 and close contacts FRS2, the motor QTM is stopped and a contactor FRCW is energized for causing the motor FM to drive the table to the right at feed-speed. When the winding of the feed-right contactor FRCW is energized, a relay FRRW is also energized. If now a dog-operated switch is actuated to open contact TLS1 and close contacts TLS2, the contactor FRCW is deenergized and a contactor TLCW is actuated for causing the motor QTM to traverse the table quickly to the left. During such movement, the dog-operated contacts FRS1 are opened and the contacts FRS2 are closed, but this is without effect since contacts TLC5 are closed and the contacts TLC1 are opened. When a dog-operated stop switch SP is actuated, the motor QTM is de-energized and the table is brought to rest. The dogs may be hinged, as described in Specification 702,226 so that each one operates its associated switch only when the table is travelling in one given direction. It is then possible to change from feed-right to feed-left operation by opening a hand-operation switch TSL. When a dog-operated switch closes its contacts FLS2 and establishes a circuit for the feed-left relay FLRW, the feed-left contactor FLOW does not respond immediately, but is closed after the feed-right contactor FRCW is opened by the interruption of contacts FLRC1 of the relay FLRW. If the switch TSL is kept closed, however, the feedright operation is continued despite close of the contacts FLS2. While the system is set for automatic operation, depression of the push-button TLPB energizes the contactor TLCW provided that neither of the contactors FLCW, TRCW are closed. Similarly, the contact TRCW is energized and maintained upon depression of the push-button TRPB. Actuation of the push-button FLPB energizes contactor FLCW provided neither of the contactors TRCW, FRCW are closed. Similarly, the contactor FRCW is energized and maintained by depressing push-button FRPB. The system is set for hand operation by opening contacts AU1-AU4 and closing contacts H1, H2. Depression of the push-buttons TLPB or TRPB energizes contactors TLCW or TRCW, but, in this case, the contactors are not selfmaintained. Actuation of push-buttons FLPB or FRPB energizes contactors FLCW or FRCW, these contactors being self-maintained. A contactor SCW for spindle motor SM is adapted to be energized when any of the contactors TRCW, TLCW, FRCW or FLCW are closed provided that selector switch SL is in a first position. When the selector switch is in its second position, the spindle contactor is closed only when the contactors FRCW, FLCW are closed. A back-lash eliminator as described in Specification 664,824, [Group XXII], has a solenoid SOL such as the eliminator is operative only when the solenoid is energized. The eliminator, which is used in connection with a lead screw for driving the table, is required only when feeding in one direction, as selected by the hand-switch HD.