Patent GB-372329-A (GB)
Title: Improvements in hollow-spindle lathes
IPC: B23B13/00
Filed: 1931-01-26
Abstract: 372,329. Making nuts. WORRELL, G. C., 2, Pleasant Street, Westfield, lassa. chusetts, U.S.A. Jan. 26, 1931, No. 2550. [Class 83 (iii).] Lathes.-In a hollow-spindle lathe for forming objects from bar-stock, a reciprocable tool shaft is provided in alignment with the work spindle and carries at its inner end a tool which acts as the sole gauging stop for the work as the latter is fed forwards in the spindle and which is subsequently fed axially so as to enter the work. As applied to the making of nuts, the machine comprises a hollow work spindle 5, an axially reciprocating shaft 60 carrying a non-rotatable drill D and two lever rests 70, 71, pivoted on a shaft 72 parallel to the workspindle, the operations of the lathe being controlled by cams on a shaft 37. The spindle 5 is rotated through a chain 7 from a motor M or by a belt or gearing, and drives the cam shaft through spur gearing 26, bevel gears 30, spur gears 35, and worm gearing 36. In operation, the chuck is released by a cam 45 having a track 46 which actuates a yoke lever 40, and the bar stock R is fed against the stationary drill D by a weight W which is connected by a cable 54 to a plunger 52 slidable within a tube 50 forming an extension of the spindle 5, a slot being provided in the tube to allow the cable loop on the plunger to slide therethrough. The chuck is then closed by the cam 45 and the drill D is fed into the rotating work by a cam 68 acting on a roller 66 on the shaft 60. As the drill approaches the forward limit of its feed a turning and chamfering tool F, Fig. 7, mounted on the lever rest 70 is brought against the work by a cam track 85 on a drum 66 which oscillates a lever 78, Fig. 3, pivoted at 80 and connected to the rest by a link. The tool F turns a neck on the stock and forms the chamfer, the drill being withdrawn whilst it is operating, and as it is finishing its work and is swung away a cutting-off tool C, mounted on the lever rest 71, is brought up by a cam track 86 on the drum 66 acting on a lever 79 linked to the rest, thereby cutting off the finished nut. The cutting-off tool is narrower than the neck formed by the tool F so that a washer, flange or seat n will be left on the face of each nut. The tools and the timing of their operations may be varied for producing articles other than nuts. The drill D may be replaced by a combined drilling and screwing tool, in which case the relative speeds of the operative parts of the machine are modified to allow the work to be both drilled and screwed and the end of the drill enters further into the end of the bar so as to act as a stop at the base of the recess left after the finished work has been cut off. Chucks.-The front end of the hollow spindle 5 is internally bevelled at 10, Fig. 2, to coact with a split collet 12 on the end of a sleeve 11 within the spindle. Flanges 14, 15 are rigidly connected to the spindle and sleeve respectively, the former having levers 16 pivoted thereto which have cam ends acting against the flange 15 for closing the chuck when the levers are rocked by a bell 20 which is keyed to the spindle at 21 and is reciprocated by the camactuated yoke lever 40, Fig. 1. The cam ends of the levers 16 operate in radial slots 17 in the flange 15 in order to cause the collet to be rotated positively with the spindle.