Patent GB-762368-A (GB)
Title: Improvements in or relating to control mechanism for a copying lathe
IPC: B23Q35/18
Filed: 1953-08-19
Abstract: 762,368. Copy-turreing. FISCHER AKT.- GES., G. Aug. 19, 1953 [Sept. 13, 1952], No. 22919/53. Class 83 (3). In a copying-lathe including a carriage 7, Fig. 1, movable on a bed 3 in a direction parallel with the lathe axis, a tool-slide 10 displaceable on the carriage transversely of said axis, and means for hydraulically controlling the slide from a feeler 22 co-operating with a template 26, a control mechanism is provided for automatically controlling a number of successive cuts to be taken by tool 11 on work 35: The mechanism comprises a cylindrical drum 50, Fig. 3, carrying cams in circumferential grooves and rotatable, in dependence on longitudinal feed of carriage 7, anti-clockwise as viewed in Fig. 3 during forward feed, and clockwise during return movement. The drum is mounted in carriage 7 together with a gear-box 8, Fig. 10, through which pass high and low-speed shafts 184, 183, driven in the same direction from the headstock, and a non-rotatable screwed shaft 185, all supported in the head and tail-stocks 1, 5. On a shaft 181 are fixed gears 194a, 190c and the inner part 181a of a free-wheel, and free thereon are gears 194, 195 capable of being connected to the shaft by clutches 192, 193 actuable hydraulically by pressure-fluid applied to lines 53, 54, respectively. On shaft 182 are gears 189, 190, capable of being clutched to gear 188 fixed to the shaft, by pressure-fluid applied to lines 91, 94 respectively, gear 188 meshing with gear 187 on a nut 186 threadedly engaging shaft 185. - The carriage is fed from shaft 183 via gears 194b, 194, clutch 192, shaft 181 and gears 194a, 189, 188, 187, at normal-speed, or via gears 183a, 181b, shaft 181 and gears 194a &c. as before, at half-speed. High-speed feed occurs from shaft 184 via gears 184a, 195, clutch 193, shaft 181 and gears 194a &c. as before. Return movement of the carriage is effected by releasing gears 189, 188, and engaging gears 190, 188 so that the drive from shaft 181 to shaft 182 occurs through reverse-gearing 190c, 190a, 190. High, normal or low-speed return is selected by actuating clutch 193, 192 or neither clutch, respectively. Slide 10, Fig. 9, is movable relatively to a stationary piston 12 under the control of valve 24 actuated by feeler 22 pivoted at 20 to the slide, the depth of cut for each cut being limited by a stepped member 178 moved by longitudinal movement of the drum between cuts. The cams 47, 47a, 60, 60a are fitted in the grooves of the drum for each cut and a starting cam 101 is fitted in the first groove only. Cams 60 interrupt the feed motion of the carriage 7, cams 60a interrupt the high-speed return-movement of the carriage, cams 47 reduce normal-feed-speed to half-speed and cams 47a institute high-speed-feed. The cams 47, 47a are fitted in the grooves, as required. Single-cut operation. This is attainable when valve 161 is pulled down, and lever 78 is positioned by hand to move valves 74, 75 and start the longitudinal feed at a desired speed and valve 66 is moved by lever 67 to release pressure in line 69 below valve 24 whereby the feeler is rendered operative. At the end of the cut, cam 60 actuates valve 49 to stop the feed and force valve 66 to the right, so that liquid enters line 69 to raise valve 24, and hence slide 10, from the work. In moving, slide 10 actuates, via rack 15, pinion 16, shaft 17, and cams 18, 19, a control-element IV to initiate highspeed return of the carriage, which is stopped by cam 60a. Normal and half-speed return movements, which are not used during automatic working of the lathe, may be selected during single-cut working by hand lever 78. Automatic operation. With the parts positioned as in Fig. 3, this is initiated by cam 101 actuating valve 49, which moves piston 76 and hence valves 74, 75, 66 to free slide 10, which moves towards the work and actuates element IV so that fluid is applied to lines 53, 91 to engage normal-speed-feed. At the end of the cut, cam 60 actuates valve 49 as in single-cut operation, and a piston 97 is lowered to move, via levers 99, 34, a slide-member 31 on which valves 42, 49 are mounted, downwards out of reach of the cams of the drum. Also, fluid is supplied to move piston 139 which, via lever 135, displaces drum 50 to align the next row of cams with the actuating-members of valves 42, 49, and to move the member 178 to its second position. Subsequently slide 31 is raised and the high-speed-return of the carriage is initiated, and ultimately stopped by cam 60a of said second row. The movement of valve 49 causes movement of piston 76 and valves 74, 75, 66 to initiate the next cut. Successive cuts follow until the high-speed-return of the carriage is stopped by the cam 60a in the last groove of the drum, the preceding axial-movement of drum 50 having actuated a valve 111 which prevents slide 10 from moving towards the work again, and the cycle is stopped. Transfer from automatic operation to single-cut operation is effected by pushing in valve 162 to cause lowering of valve 161, and transfer in the reverse sense is effected by pressing in valve 161 and moving valve 105 against spring 106.