GB205551A - Improvements in the method of and means for cutting or generating helical teeth of toothed gearing wheels - Google Patents

Abstract

205,551. Brown & Sons (Huddersfield), Ltd., D., and Green, A. July 15, 1922. Gear-cutting.-In a machine for generating helical or spur gearing by means of a rack-tooth cutter which, by relative rolling movement, generates the tooth profile on both sides of a tooth space simultaneously, the cutter is fed to the blank in such a way that the bulk of the cutting is effected by the outer and leading edges of each rack-tooth, the rear cutting-edge serving merely to impart the required profile to the flank on which it operates. Fig. 11 shows the path of the cutting tooth a into the blank, the generating motions being omitted. In order that the cutting may be effected by the edges b, c of the cutting-tooth a a tangential movement equal to the distance between the lines AB and CD is imparted to the tool during the radial feed. One stage of the operation of generating gear-teeth according to the invention is shown in Fig. 14. Fig. 1 shows the invention applied to a machine for cutting double-helical teeth on a blank 3 by means of two rack-cutters 2 reciprocating on inclined guides on a carriage 8<a>. The rotation of the blank and the vertical movement of the cutter-carriage 8<a> are effected through the usual gearing so as to produce correct rolling of the blank on the cutter. A nut 14 on the screw 9 which operates the vertical cutter-movements is formed with worm-wheel teeth and mav be driven by a worm 15 actuated through a flexible shaft 17 and shaft 18 from a handle 19. The shaft 18 is connected by change gears to the blank feedscrew 20 so that when, after each revolution of the blank, the latter is fed towards the cutters, the required tangential movement is simultaneously imparted to the cutter-carriage. In a modification, instead of imparting tangential movement to the cutters the blank itself may be adjusted after each radial feed movement. In a further modification the invention is applied to a machine in which the cutters reciprocate in a fixed path and the rotary and tangential movements are both imparted to the blank. Fig. 17 shows one stage in the cutting of a rack in accordance with the invention.