Patent GB-212862-A (GB)
Title: Improvements in or relating to machines for cutting gear wheels or the like
IPC: B23F5/12
Filed: 1923-05-10
Abstract: 212,862. Gleason Works, (Assignees of Gleason, J., Bryan, G.H., Finsen, E., and Slade, A. P.). March 14, 1923, [Convention date]. Gear-cutting.- In a machine for generating bevel gears the blank x is adjusted so that the line of travel of the tools, which are mounted on a slide a as shown diagrammatically in Fig. 30, is parallel to a generator of the root cone of the blank, the rolling generating movement being produced by means of a bevel gear segment 47 secured to the blank spindle and having a pitch cone angle less than that of the blank, this segment 48 having a pitch cone angle less than 90‹. The pitch cone angles of the two segments are so determined that correct rolling motion of the blank on the crown gear represented by the tools is obtained. By this arrangement the line of travel of the tools may be fixed at right angles to the crowr. gear axis AB and does not require to be adjusted to the root cone of the particular blank being cut as in the usual arrangement shown in Fig. 29. The machine bed 3 is provided with stationary guides 5 carrying the tool support 6 driven from a pulley 7 connected through a friction clutch with a spindle 9. The latter carries a crank connected by a link 11 to a slotted actuating-plate 12 having blocks 14 connected to the tool slides 16 so that the oscillations of the plate 12 produce alternating reciprocating movement of the tool slides. The tools y are each mounted in a tool-box 121 pivoted at 120 to the slides 16 which move in angularly adjustable guides 124. The tools are relieved on the return stroke by means of a rod 122 which slides in a friction clamp and is moved longitudinally to operate a universally connected link 123 to withdraw the tools. Feed of the tools towards the work is effected through an arm 17 operated by a cam 19 on a shaft 20, Fig. 5, which is driven through gearing from a belt pulley 30 driven through a clutch 91 from the pulley 7. The blank carrier 35 is provided with a curved portion 36 engaging corresponding guides concentric with the axis of the crown gear represented by the tools, the blank being bodily rotated about this axis by means of a cam 42, Fig. 5, mounted on the cam-shaft 20 and acting through lever mechanism on an arm 37 secured to the carrier. The gear blank x is mounted on a support 46 and is connected through indexing-mechanism to the segment 47 engaging the stationary segment 48 so that as the blank carrier is rotated on its guides the blank is simultaneously rotated on its axis so as to give correct rolling. In operation the tools are fed into the blank which is then rolled downwardly to shape the teeth, after which the tools are given a small further feed towards the blank and the upward roll, during which the finishing cuts are taken, commences. Towards the latter part of the upward roll the tools are withdrawn and the blank indexed, the movements of the tool head being effected at the required times by the feed cam 19. The tool head may be manually operated by means of a hand wheel 61. The machine is stopped automatically on completion of a gear through the disengagement of the clutch 91 by which the power pulley 7 is connected to the main transmission pulley 30. The clutch-operating lever 96 is connected to a plunger 97, Fig. 21, and is normally held in engaging position against the action of a spring 98 by means of an arm 100 on a pivoted plate 101 which is controlled by an adjustable disc secured to a ratchet wheel 106. In operation, the ratchet wheel is set according to the number of teeth to be cut and is fed forward one tooth at each forward movement of the tool support until, when the blank is completed, the plate 101 is rocked by an abutment on its coacting disc to release the plunger 97 and stop the machine. The clutch may be manually operated from a hand wheel 117. Indexing.- The blank-supporting sleeve 46, Figs. 9 and 12, carries a dividing-wheel 65 and ratchet wheel 66 the latter being operated by a pawl 67 pivoted on a collar 68. The bevel segment 47 is keyed to a sleeve carrying an arm 70 supporting a lever 72 which normally locks the generating-segment and index wheel together. As the segment turns a tail 76 on the lever engages a pivoted abutment to withdraw both the locking dog 73 and an integral member 83. Thereupon the pawl 67 is caused by a spring to engage its ratchet wheel and on further movement of the arm 70 a toothed segment 78 on the arm engages stationary teeth 79 and is thereby rotated, this rotation being transmitted by a gear 81 to the collar 68. This causes the pawl 67 to rotate the gear blank support through one tooth after which the dog 73 is re-engaged and the pawl 67 withdrawn.