GB732279A - Control means for a machine tool which is to operate on a predetermined cycle - Google Patents

Abstract

732,279. Switching systems. HERBERT, Ltd., A. Sept. 30, 1953 (Feb. 28, 1953], No. 5698/53. Class 38 (4). [Also in Group XXII] In a control means for a machine tool required to operate on a predetermined cycle, a magnetic wire or tape recorder, having oscillations of different frequencies pre-imposed on the wire or tape dependent upon the different operations, is employed and a plurality of relays are connected to receive the output of the replay head of the recorder and each tuned to respond only to one of the said frequencies the tuned relays being connected, preferably through slave relays, to actuate electroresponsive devices associated with slides or other elements of the machine tool. A horizontal boring machine, Fig. 1, with a radiallyfed tool-carrier 22, has a non-rotating workpiece 16 carried by a holder 15 mounted on a cross-slide 14 and longitudinal slide 13. The motions of the slides &c. are derived from hydraulic cylinder and plunger arrangements (not shown). The motive fluid, supplied from a motor-driven pump, is controlled by solenoidoperated valves 28, 29. The tool slide 22 is moved automatically to withdraw the tool when the work is completed. A control panel 31 adjacent the headstock has press-button switches 32 for the six slide &c., movements and other switches 32a for the main power service. The tape recorder 35 is arranged below the switch panel with tape reels 36, 37, and the " record "/"eraze"/" play-back" head 38 is shown diagrammatically. Control circuit. The six movements required in the machine described are represented by six oscillator valves 40-45, Fig. 2, with circuits to maintain a constant oscillatory signal on each of the outlet lines 40a-45, the lines being open-circuited at the press-button switches 32. Each switch is connected to a mixing unit 47 by a line to the control grid of, for example, half a double triode valve 48, the anodes of the respective half sections being connected in parallel so as to have a common output line 49. A stabilized D.C. voltage is supplied from a power pack 52 which receives A.C. voltage along the lines 53, 54, in common with the recorder 35. Thus, actuation of one or more of the switches 32 will enable an oscillatory signal to be fed to the " record " input of the recorder over the line 58, or to one of the tuned relays over the line 66. The tuned relays may be of the type in which a reed vibrates to supply D.C. pulses when the appro. priate frequency is applied across its winding. The pulses are supplied to relays 68, each controlling a slave relay 69 which, establishes a positive circuit to control the solenoids 160- 165 for the solenoids of the hydraulic control valves. The machines may be controlled in at least two ways: (1) the controls may be used to move the machine parts up to pre-set stops to produce a pilot workpiece, the tape recorder being set to "record," so that when the operator has completed the workpiece in this manner the recorder may be changed to "replay" and the cycle of operations repeated automatically; (2) the operator may use the controls to carry out a pilot operation with the usual gauges &c., starting and stopping the slides by the press-buttons, the recorder being set to " record ". On completion of a workpiece by this method the tape may be played back to produce the workpieces automatically. The machine may also be set up by using a model similar to a copying operation, the sequence being subsequently repeatable from the tape. The electro-responsive devices may be electric motors and brakes in lieu of solenoid operated valves and cylinders, and pistons, or electromagnetic clutches may be employed. When hydraulic or pneumatic power is used, use could be made of further solenoid valves to give different speeds of the slides &c., at different points in the cycle.