GB190323560A - Improvements in Screw Cutting Lathes or Machines. - Google Patents

Abstract

23,560. Daniell Ltd., S. A., and Bodington, J. Oct. 30. Lathes.-A screw-cutting lathe is arranged to operate automatically after being set and started,the machine being automatically stopped when the thread has been cut to the desired depth. When applied to the cutting of double threads, two compound tool-slides c, d, Fig. 5, are mounted on feed. slides c', d', and are pressed together by springs on the saddle e, their inward movements being limited by cams on them engaging a cam f' on a feedspindle f on the saddle. The work and leading- screw m are rotated during the cutting stroke by a pulley l and train of gearing F, and have a quick return by means of a pulley i and train of gearing R. The belt fork s is actuated from a tappet shaft n, held in its middle position by springs n<1>, and displaced by the saddle at the end of each stroke, as determined by tappets n<2>. At the end of the forward stroke, a cam on the lead-screw actuates a lever, separating the tool-slides to facilitate the turning of the feed-spindle, and a toothed projection o<2> on a pinion o engages a corresponding projection on a wheel t driven through a shaft v' from the gearing F or R. The partial rotation of the tappet shaft rotates the feed-spindle half a revolution through spiral gearing f<3>, n<3>, and operates the belt fork, the movement of which is completed by springs between discs v, v<1> on the shaft v'. One of the discs is fixed to the shaft, and the other carries a pinion geared to the wheel t. The spiral wheel f<3> carries a handle y with a spring plunger engaging a notched disc f on the feed-spindle, the plunger being temporarily tripped during the movement of the handle in one direction so that the tool-slides may be gradually fed up. When the thread has reached the desired depth, the plunger falls into a deeper notch, and then actuates a cam to release a latch 6 which holds the belt fork with the belt on the loose pulley. The springs and cam surfaces on the slides and feed-spindle may be replaced by right and left handed screws and nuts, the discs v, v<1> with their springs being omitted. The latch 6 may release a weighted rod to operate the belt fork of an overhead countershaft.