GB152654A - Improvements in gear slotting machines - Google Patents

Abstract

152,654. Schaerer, O. Oct. 18, 1919, [Convention date]. Gear-cutting; tools.-A form-tool gear-shaping machine has two vertically reciprocating diametrically-opposed tool rams for cutting, two or more teeth by simultaneous or alternate working strokes, the tools being radially fed at each working stroke. An adjustable crank 32 driven through change gearing from the driving shaft 27 reciprocates a rack 33 which through a pinion 35 oscillates a shaft 34 whose movement is transmitted through pinions 40, 41, racks 36. 37, and pinions 42. 43 to the shafts 38, 39. In Fig. 1 the cutters are shown as working alternately, while the racks 36, 37 are shown as arranged for operating the cutters simultaneously. Pinions 44, 45 feathered on the shafts 38, 39 respectively engage racks fixed to the tool rams 8, 9 to reciprocate the tools. The rams are carried on slides 6, 7 connected by threaded' spindles 15, 16 to racks 13, 14 sliding in a recess of a yoke portion 2 of the frame and actuated by a pinion 12 on a spindle carrying a second pinion 17 engaging a rack 19. A cam 20 on a shaft 21<a> is rotated to actuate the rack 19 and feed the tools radially bv means of a ratchet wheel 21 intermittently operated by a lever 22, pawl 23, and oscillating lever 24 on the shaft 34. A fixed pawl 23<a> prevents backward movement of the ratchet wheel. The rack 19 is returned to the lowest position on completion of two teeth by means of a weighted lever 18. During this operation a sleeve 25 surrounding the shaft 21<a> is rotated by means of a link 26, and a projection on the sleeve lifts a lever 55 and disengages the stop lever 51 from a dividing wheel 47. The lever 55 is afterwards disengaged from the sleeve by an adjustable screw 25<b>. A link 52, Fig. 8, connects the stop lever to a jaw coupling portion 53 which is thus moved into engagement with a continuously rotating member 46. This motion is transmitted through spur and worm gearing to a table 3 carrying the blank 4. A hardened die 5 is placed beneath the blank to avoid chipping the lower edges of the teeth. A safety lever 54 attached to the stop lever raises the pawl 23 while the dividing mechanism is in operation so that the feed motion and dividing motion cannot take place simultaneously. During the next cutting operation, the upward movement of the lever 18 rotates the sleeve 25 and its projection again engages the lever 55. To obtain better ratios for the wheels operating the dividing mechanism the gear shaft 48 carries a pinion 56 engaging a pinion 57 fixed to a cam 58. The lever 51 carries a finger 59 which slides on the cam and keeps the lever 51 in its raised position through a number of revolutions of the dividinn wheel according to the ratio of the gearing 56, 57. When gears with an odd number of teeth are cut, the tools 10<b>, 11<b> are shaped as shown in Fig. 6. For cutting small teeth, the tools may cut a number of teeth at one operation, the dividing mechanism being made to turn the blank by an amount corresponding to the number of teeth cut.