GB464342A - Improvements relating to screw cutting or chasing devices for lathes and the like - Google Patents

Abstract

464,342. Chasing - attachments. MARKS, F. W., and WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. Oct. 15, 1935, No. 28489. [Class 83 (iii)] A screw cutting or chasing attachment, particularly for use with capstan or turret lathes, has a base 10 rotatably carrying a lead screw 20 driven from the headstock of the lathe or the like, and a tool-holder 14 mounted to be traversed across the base by the lead screw, means being provided for automatically disengaging the tool holder from the lead screw, returning it to the starting position, and automatically engaging it. The tool-holding slide 14 carrying the chaser 17 moves across the base in a guideway 15, Fig. 4, of an intermediate slide 13. The latter moves at rightangles to the first slide on the base 10 and through a spring 22, Fig. 5, housed within it, forces a half-nut 21 carried by the upper slide into engagement with the lead screw which is driven from the lathe headstock by means not shown. A train of interchangeable gearing 32-35, Fig. 2, is adapted through cam means to rock the shaft 37 whereby a locking bolt 25, Fig. 4, at the end opposite from the gearing is withdrawn from the lower slide at the end of a predetermined thread cutting movement, the slide then being moved by a cam 41, Fig. 5, to release the half nut and lead screw, the upper slide is thereupon automatically returned to its initial position, determined by a stop bolt, by spring means and the halfnut, and lead screw are re-engaged to continue the cutting. By changing the gearing 32-35 the displacement of the cutting tool may be varied and provision for cutting taper threads is attained by clamping the base at an angle to the axis of the work.