Patent GB-158567-A (GB)
Title: Method of and machine for grinding the profiles of gear teeth
IPC: B23F5/02
Filed: 1921-01-27
Abstract: 158,567. Wingquist, S. G. Feb. 5,1920 [Convention date]. Gear-wheels, grinding and trueing teeth of.- The tooth profiles are ground by a rotary grinding disc so shaped that one and the same point, line, or small surface of the disc, having a constant position relatively to the axis of the disc, is used for grinding, the point, being moved relatively to the toothed wheel blank along the line of contact of the tooth with an imaginary tooth at a speed equal to that of the point of contact of the teeth; the operating-surface of the disc is preferably narrow so that every point thereof passes and contacts with every part of the tooth profile. In grinding a tooth with an involute profile, a small surface a, Fig. 3, of the grinding-disc S is moved along the line of contact L, which is tangential to the base circle C', at a speed equal to that of the periphery of the base circle, the tooth profile being simultaneously rotated from position I to position VI; in a modification, the blank may be moved and the grinding-disc stationary. A machine for grinding teeth according to this method is shown in Figs. 7 and 9. On a frame 1 is mounted a slide 3 adjustable by means of a screw 5 and carrying a grinding-disc 4 having a peripheral grinding ring on one of its faces. On the frame is a guideway 6 for a slide 7 movable parallel to the face of the grinding-disc and carrying a slide 8 movable at right-angles to the direction of movement of the slide 7. The slide 7 is moved by a hand-wheel 9 operatively connected to a screw 10 engaging a bushing 11 screwed into the slideway 6, and keyed to the screw is a spiral gear 12 engaging a spiral gear 13 whereby the slide 8 is moved. The slide 8 carries a shaft 15, on one end of which a blank H is mounted, the other end of the shaft carrying a cylinder 16 the diameter of which is equal to that of the base circle of the wheel H; adjacent to the cylinder the shaft also carries an arm 17 with a screw 18 thereon adapted to co-operate with an indexing-disc 19 attached to the cylinder 16. A band 20, preferably of steel, passes around'the cylinder and has its ends secured to standards 21, 22 on the slide 7, whereby, on movement of the slide 8, the cylinder is rotated at a speed corresponding to the speed of the slide. The slide carries a pawl 24 co-operating with teeth 25 on the bushing 11 whereby this is rotated at the end of the stroke of the slide to give a feed to the slide 7. In operation, the hand-wheel 9 is rotated forwards and backwards, the movements of the wheel blank resulting in the grinding of the tooth along lines x. Opposite sides of a tooth are ground by reversing the wheel blank on its shaft, or, to avoid removal of the blank, the guide 6 and the slides 7, 8 may be rotatable about a journal 27, Fig. 11, secured to the base 1. The grinding-disc may also be moved to grind along lines parallel to the axis of the blank or at right-angles thereto. Both sides of the same tooth, or opposite or corresponding sides of different teeth, may be operated upon simultaneously, by the use of more than one grinding-disc. In grinding cycloidal teeth having only a convex part, the grinding- disc S, Fig. 6, is moved by a cylinder C<4> of diameter equal to that of the rolling circle and pivoted at t to a link l swinging about the centre of the pitch circle C<6>. The link has an extension with a journal t, on which slides a frame s, which carries the grinding-disc and is pivoted to the cylinder C<4>. On rolling the cylinder on the pitch circle under control of the link l, the operative surface of the grinding-disc generates an epicycloid Z. In a modification, the grinding-disc may have two operative surfaces a as shown in Fig. 20.