517,038. Gear-cutting. CAMPBELL, W. A., and OHLSON.-E. G. July 16, 1938, No. 21129. [Class 83 (iii)] In a bevel gear generating machine, a pair of rotary cutting or grinding discs 27 with plane operative faces are mounted in a cutter head which is rotated in unison with the blank to give the generating movement while the tools are reciprocated to and from the blank cone apex. The blank 1 is mounted on a dividing - head 2 angularly adjustable on a base 25 about a pivot 20 to set the blank to the required cone angle. The blank-spindle carries a worm wheel 3 connected through gearing 4 ... 8 shaft 9 gears 10 ... 12 shaft 13, one way indexing-coupling 75 shaft 77, gears 78, 79, shaft 112 spiral gears 80, 110, Fig. 4, and reversing-gearing 105 to a power pulley 22. The spiral gear 80 is also connected through worm gearing 116 to a cutter head 31-which is thus driven in unison with the blank to impart the generating crown wheel movements to the cutters, The cutters consist of two plane-sided toothed discs of about nine inches diameter and are adjustable in their mountings so that the plane faces converge to the blank cone apex. A pulley 46 which may be operated by the same belt as that which drives the pulley 22, is connected through gears 47, 42, to two universal parallel shafts 39, shafts 36 and worm gearing 34, to drive the cutter spindles. The gear 47 is also connected through shaft 49 to a crank disc 53 which through rods 55 reciprocates the cutter slides 56 to move the cutters along the blank teeth. The cutter slides move in guides 56a in a slide 32a which may be angularly adjusted to set the cutters 'to the required root angle. The slide 32a is in turn mounted in a slide 30a which may be angularly adjusted on the part 32 of the cutter head to vary the pressure angle of the teeth represented by the cutters. The cutter head rotates in a frame 60 which can move axially to withdraw the cutters from the work, The reversing-gearing forming part of the generating-traih consists of a shaft 88, Fig. 4, driven from the pulley 22 and carrying loose gears 87, 86 connected directly and through an idler respectively to gears 105, 108 on the shaft 106 of the gear 80. The gears 86, 87, may be selectively locked to the shaft 88 by interconnected coupling-members 92, 93, operated through a rod 102 by a fixed stop 124. The gears ratios are arranged so that one turn of the shaft 77 produces a rotation through two teeth of the blank. When in operation the cutters have rolled clear of the blank a cam plate 120 on the cutter head engages a fixed stop 121 to withdraw the culter head and the tools. By this movement the lever 102 is operated by the stop 124 to actuate the reversing-mechanism for the return roll of the cutters and work. During this return roll the disc 74 of, the coupling remains stationary during a complete reverse rotation of the disc 75 thus indexing the blank through two pitches. For this purpose the driving-dog 130, Fig. 6, which during the operative forward roll drives the pawl 132 in direction of arrow C moves past the lower end of plunger 131 and moves it to the Fig. 7 position. On completion of the reverse roll a second cam plate 126 restores the cutter head and again actuates the reversing-mechanism whereupon the driving-dog 130 again engages pawl 132 for the next operative roll. For cutting spiral bevels a transverse slide may be mounted on the cutter head so that the tools are moved in an oblique path across the blank.