Patent GB-143622-A (GB)
Title: Improvements in or relating to pattern reproduction
IPC: B23Q35/10
Filed: 1919-02-25
Abstract: 143,622. British United Shoe Machinery Co., (United Shoe Machinery Corporation). Feb. 25, 1919. Lathes.-A copying-mechanism of the kind in which a two-dimension relative movement occurs between the model and tracer is provided with means for varying the adjustment of the mechanism interconnecting the model and work and the tracer and implement during operation, in order to obtain a non-geometric reproduction. The invention is described with reference to last-turning lathes, but is stated to be applicable to such other operations as gun-stock and hat-block turning. Headstock-traversing mechanism; stop-motions. -Work blanks are held between driving-centres 82, 84, Figs. 1 and 2, carried by a carriage 70 and tailstock-centres 74, 76 carried by a slide on the carriage. The carriage is traversed by a screw 66 driven at 64 through a change-speed gear 52 of the sliding-swinging arm type from a pinion 48 on a shaft 42 clutched at 44 to a sprocket 40 chaindriven at 36 through a two-speed drive 18, 20 from a motor pinion 12. At the end of a traverse, a cam 318 is interposed in the path of a sliding pin 308 carried by a lever oscillated by pins carried by one of the members of the gear 52, thus moving over the clutch lever 310 fitted with a spring detent 314. Toothed driving-gear; reversing-mechanism.- The shaft 42 is splined to a pinion meshing with the wheel 335, Fig. 13. The spindles carrying the driving-centres 82, 84 rotate either in the same or in opposite directions, according to the position of sliding wheels 330, 336, the wheel 336 being driven either directly from the wheel 335 or through the pinion 330. Spindles.-The pins that operate the lever carrying the pin 308 are so arranged on their carrying- gear that the spindles are always stopped on shifting the clutch 44 in a constant angular position such that the work is most readily removed. Speed-controlling and clutch-operating mechanism.-The two-speed drive 18, 20 is controlled by a clutch operated by an arm 30, Fig. 3, on a shaft 32 bevel-geared to a shaft 192 rocked by a cam 210, Fig. 1, mounted on the model carriage. Clamping tailstocks. - The slide carrying the tailstock centres is clamped, after adjustment, by a screw and hand-wheel acting through the adjusting-gib. Mounting centres.-The driving-centre 100, Fig. 6, for the model is pivotally mounted at 112, as limited by pins and slots 114, to a slide 116 displaceable laterally on the spindle nose. The tailstock centre is similarly mounted. Copying-mechanism.-The model tailstock is adjustable in a slide on the headstock slide which is movable on ways on a bar 92, Figs. 1 and 2, and carries a rack 234 connected to an adjustable rack 230 through a pinion 238. A rack 232 on the work headstock slide is correspondingly connected to a fixed rack 228 through a pinion 242. The pinions 238, 242 are mounted on studs on slides in an arm 218 having an adjustable fulcrum 222 to provide for varying the length scale of reproduction. In order to vary this scale during a traverse, the rack 230 is adjustable by a screw 246 controlled by a pinion nut and a rack 250 adjust.- ably connected at 252, Fig. 3, to either side of the fulcrum of a working link 206 linked to a work-shaft 190 operated by cams 198, 200, Fig. 1, mounted on the model carriage. To cause a bending of the work relatively to the model, one of the model centres is displaced laterally during rotation, and to cause a parallel displacement of certain sections, both centres are displaced. The displacement is controlled by cams 178, 184 adjustably mounted on the model carriage and actuating rock-shafts connected through adjustable linkage similar to 206 &c. to shafts 106, 108 carrying annular wheels 152, Fig. 6. The centrecarrying slides 110 are fitted with racks engaging pinions on shafts 142 keyed to planet-carriers 144. Planet-carriers 136 rotate with the model-driving sleeves 134 geared at 122 to shafts 126 bevelgeared to the shaft 42 through a cross-shaft 132, Fig. 1, so that the model and work rotate at equal speeds. Annular wheels 148 are fixed. When the shafts 106, 108 are stationary, the planet-carriers, and consequently the slides 110 and their pinion shafts, rotate at the same speed. When, however, the shafts 106, 108 are rocked, the pinions rotate relatively to the slides, and the centres are displaced accordingly. The transverse dimensions of the work are controlled by lateral motions of the tracer and cutter carriages. The cutters 258, 260, Figs. 1 and 2, are driven by motors mounted in cradles 320, Fig. 11, rocking about centres 322 as controlled by pins and slots 326 and screws 324. The centres 322 a.re so located that a small adjustment for cutter diameter will not appreciably vary the height of the cutter above its carriage. Errors in reproduction due to slight variation in cutter diameter, on account of grinding, &c. are thus avoided. The cutter axes are arranged at an angle as shown in Fig. 2, on a carriage 254, Fig. 5, movable on ways 256, Fig. 2. The tracer 298 is mounted on a slide 294 adjustable on a carriage 272 movable on ways 274. The ways 256, 274 are mounted at an angle of about 15 degrees to the horizontal. The cutter and tracer axes move in planes passing through the axes of the work and model respectively. The carriage 254 is pivoted at 280 to a lever 276 slotted at 278 to engage a fixed fulcrum pin and carrying a slide 282 connected to the carriage 272 through a link 290. The slide is adjusted by a screw geared to a hand-wheel 288 to vary the relative transverse dimensions of the work and model.