Patent GB-733378-A (GB)
Title: Improvements in automatic single spindle lathes
IPC: B23Q5/26
Filed: 1952-12-31
Abstract: 733,378. Automatic lathes. TAREX SOC. ANON. Dec. 31, 1952 [Feb. 16, 1952], No. 33053/52. Class 83 (3). An automatic single-spindle turret lathe comprises an electric motor drive coupled with change-speed and control devices giving changes of spindle speed and direction, a cam-shaft with flat cams operating feeler members, a hydraulic servomotor and distributer valve for each tool-holder and control devices for giving the valve members a movement which is a function of both the movement produced by the cam and feeler and also of the movement of the tool-holder. The work spindle B is driven through a speed-change and reversing device VB and an electric motor MB. The controls for this may be electric, as described, or hydraulic or pneumatic. The controls shown comprise a drum T,'Fig. 1, with adjustable dogs t1, t2 &c. operating switches n1, n2, &c., the drum being secured to the end of the main cam-shaft C. Front and rear tool-slides G2, G1, respectively, and a turret tool-slide Gp are operated by hydraulic servomotors comprising piston and cylinder elements 9, 10, respectively. These are supplied with fluid from an electrically-driven pump O through distributer valves D1, D2, &c. The latter comprise pistons 12, sliding in cylinders 11, Fig. 2, and pressed to the left by light springs 46, against lever arms b which have springs 14 (stronger than the springs 46), urging the arms to the right. Each servo-piston has its own control valve D1 &c., operation of which is effected by the combined movements derived from the camshaft C and by the tool-slide itself. This is effected by a peripheral cam c1 &c., engaging a feeler m, Fig. 2, on a bell-crank 2 carrying an adjustable link 6 connected to a slidable rod P which carries a pulley-bracket 8. A cable passes around the pulley v on the bracket and through a series of jockey pulleys and is led to the lever b at one end and to a tool slide G at the other end. Thus the control valve 12 is restored to its normal position each time an increment of movement is given to the tool slide. Turret operation. The tool-turret 20, Fig. 1, is indexed by Geneva mechanism 21, 22, and locked by a cam- and spring-operated pin 35. The Geneva mechanism is driven through gearing and a one-revolution clutch A from the motor MC for driving the cam-shaft. The onerevolution clutch is operated by solenoid 23 controlled from the switch mechanism i, &c. of the control device PC which also controls the operation of motor MC. Longitudinal movement of the turret is effected by a servo-device similar to that used for the other tool slides and supplying pressure to the head 10 of a stationary piston 9 over which slides a cylinder 39. The latter in turn slides within the turret casing Gp. The cylinder 39 is connected by a link 40 and crank 41 to the turret-indexing gear 43 so that the movement of the turret casing is accelerated at the beginning of the return stroke through the combined movement of the fluid-pressure and mechanical drives. A modified movement for the turret is described in which, in place of the cable fp, a tappet moved by linkage and rack and pinion mechanism from the cam-shaft operates the control valve for the longitudinal feed, the valve being formed as part of the turret casing and moving therewith. Specification 733,379 is referred to.