GB396292A - Improvements in or relating to automatic lathes - Google Patents

Abstract

396,292. Lathes. HAHN, H., HAHN, O., and TESSKY, K., (trading as INDEXWERKE HAHN & KOLB), Esslingen-on- Neckar, Germany. Jan. 11, 1933, No. 894. Convention date, Jan. 20, 1932. Addition to 382,950. [Class 83 (iii).] The bar feed mechanism for an automatic lathe described in the parent Specification is modified to effect the automatic feed of the stock bars from a magazine. The lever 80 controlled by the cam 6 to operate the spool 5 of the feed mechanism is connected to a pawl 210 which at each feed step intermittently rotates a control wheel 201 carrying an adjustable tappet 202. The control wheel 201 is normally prevented from moving backwards under the influence of a coil spring by a locking pawl 213. After a predetermined number of feed steps, chosen so that the end of the bar 8 being worked has passed clear of the bar guide but is not yet exhausted, Fig. 1, the tappet 202 acts through a lever 203 to withdraw a roller 236 from a cam path on a splined clutch member 205 which is then moved forward by a spring 238 into contact with clutch teeth on a continuously driven worm wheel 206. The shaft 204 is rotated through one revolution before the clutch teeth are again disengaged, and during this movement a cam 207 on the shaft 204 acts through a bell-crank lever 208 on a member 209. This causes the pawl 210, and locking pawl 213 to be lifted from the control wheel, which is thereupon returned by its spring. A crank 239 on the shaft 204 rocks a toothed segment 240 engaging a pinion 218 on a wheel 219 constituting one of a pair of wheels connected by an endless rope 242. The rope carries a stop 244 which moves back the plunger 23 and associated parts and raises the weight 29. A cam 222 on the shaft 204 row acts through lever mechanism 223 to withdraw a shutter 224 from the bottom of a stock bar magazine 243 and allow a fresh bar to descend into the bar guide. The segment 240 is then swung back, allowing the plunger 23 to be moved by the weight 29 so that it engages behind the fresh stock bar which then follows up the bar 8, until it is finally caused to enter the chuck and eject the remnant of the bar 8 in the manner described in the parent Specification. In a modification the feed wheel 201 may be replaced by a rack bar which is fed forward by a pawl and returned by a weight or other means.