GB494645A - Improvements in electro-mechanical control devices for lathes and other machine tools - Google Patents

Abstract

494,645. Lathes &c. COTAL, J. March 10, 1938, No. 7492. Convention date, March 11, 1937. [Class 83 (iii)] A machine tool such as a lathe has two carriages movable independently by means consisting of a driving wheel located between two driven wheels each controlling the feed mechanism of one of the carriages an electromagnetic clutch being located between each driven wheel and the driving wheel for engaging the required feed. A worm-wheel 3 driven from a feed shaft 4 through gears 5 and 7 has annular armatures 8, 9 one on either side connected by studs 10 movable axially through the worm-wheel. The armatures coact with electromagnets 15, 16 energized by means of collector rings 17, 18 and secured respectively to gears 11, 12. The gear 11 operates the longitudinal feed of the carriage 1 through rack-and-pinion gearing and the gear 12 operates the transverse feed of the cross-slide 2. The contacts 19, 20 of the collector rings are connected by lines 21, 22 to terminals 23, 25 of two-pole switches C1, C2, connected in series to a supply 28. Parallel circuits from the switch poles 24, 26 are connected through electromagnet coils 30, 31 and switch 32 to the frame at 29. The switches are operated by a lever 34 which is normally held in the neutral position shown by a spring 36. To actuate the longitudinal feed the switch 32 is closed and the switch C<1> is also closed by moving the lever 34 in direction of arrow f<1>. This energizes the coil 15 and drives the gear 11 while the coil 30 holds the lever 34 in position. Similarly movement of the lever 34 in the direction of arrow f<2> actuates the cross-feed of the slide 2. Either feed may be stopped by opening switch 32 which causes lever 34 to be returned to neutral. For automatic stopping of the longitudinal feed a projecting dog 56 carried by a rotatable head 51 may be moved by a lever 52 so that it coacts with any one of a number of stops 57 on a stop bar 58. When the projection engages a stop, a plunger 48 is pushed back to operate a switch 46 to stop the feed, the saddle being then returned by hand. Similarly for stopping the cross-feed a projection 59 on the cross-slide coacts with one of a number of stops 60 on a rotatable stop bar 61 to operate a switch 47, and break the circuit 22. The invention is also applicable to other machine tools.