Patent GB-153631-A (GB)
Title: Improvements in gear cutting machines
IPC: B23F5/12
Filed: 1919-07-09
Abstract: 153,631. Smith & Coventry, and Wright, I. H. July 9, 1919. Gear-cutting.-In a bevel-gear cutting-machine of the type having cutting-tools operating simultaneously on both sides of a tooth and reciprocated on guide-arms controlled by a templet, means are provided for angularly moving the work during the cutting-stroke to cut helical teeth. The driving-shaft carries coned pulleys 13 and drives through gearing the crank-disk 11 which, by means of the link 9, oscillates a toothed sector 7 engaging a pinion 6 on a shaft e carrying one of the slide-actuating pinions h. The cutter slides a, b, carried by balanced guide-arms c, d, controlled by a generator plate or templet n are reciprocated by means of racks g, i engaging the pinions f, h respectively. The generator plate n, operating as described in Specification 9849/13, is traversed on a slide q by a sector r operated by a connecting-rod s and arm t from a worm w on a shaft x. This shaft carries a bevel-wheel z engaging a bevel-wheel 2 on a threaded shaft 3, Fig. 5, operating the work-carrying table 5. The latter carries a saddle 25 swivelling about the vertical axis of the machine and adjustable by means of a shaft 26 operating a rack pinion 29 engaging a fixed rack 30. The toothed sector 7 also engages a spur-wheel 14 which, through gearing shown in Figs. 2 and 3, oscillates the pinion 36 engaging a rack on the shaft 38 which operates a slide 42. The shaft 38 carries a feathered pinion 39 engaging a pinion 40, Fig. 3, on the shaft 26. The rotation of the shaft 38 by the rolling of the pinion 39 on its rack compensates for the angular movement of the saddle 25, and secures uniform reciprocation of the slide 42. An angularly adjustable grooved member 43 is engaged by a block on a sliding rack 48 which engages a sector 50 on the blank spindle 51. The sector has an adjustable pawl 53, Fig. 4, engaging the dividing wheel 55, and its oscillation causes the pawl to rotate the blank spindle during the cutting stroke by an amount determined by the angularity of the member 43, while a detent 54 carried by a bracket on the saddle holds the spindle during the return stroke. By using the reverse gear operated by a hand lever 21 and reversing the pawl detent helices of opposite hand may be cut. The blank feed is operated from the shaft carrying the crank disk 11 which through worm gearing drives a shaft 59, Fig. 2, carrying a crank disk 60 operating a ratchet wheel 61 the movement of which is transmitted through worm gearing and a clutch 68, Fig. 5, to the shaft 3. The feed may be automatically stopped by a projection on the table engaging a. trip rod 69 to release the clutch 68. The tools 70 are each carried by a block mounted on a pin 72, Fig. 9, carried in a bracket 73 having a bevelled pinion 76 engaging a, pivoted sector 77. The latter is frictionally clamped to a plate 79 which is actuated to rotate the pinion 76 and swing the cutters clear of the blank by a rod 81 having adjustable stops thereon and passing through a stop on the cutter slide arm. Straight tooth wheels may be cut bv holding the blank stationary during the cutting stroke and rotating it as described during the return stroke.