Patent GB-358031-A (GB)
Title: Improvements in or relating to gear generating machines
IPC: B23F5/12
Filed: 1930-03-28
Abstract: 358,031. Gear cutting. GLEASON WORKS, 1000, University Avenue, Rochester, New York, U.S.A.-(Assignees of Finsen, E. ; 1000, University Avenue, Rochester, New York, U.S.A.) March 28, 1930, No. 9996. Convention date, June 6, 1929. Void [Published under Sect. 91 of the Acts]. [Class 83 (iii).] In a gear generating machine of the type in which the generating roll is produced by the oscillation of a cradle carrying the work or tool and by rotation of the work spindle in unison with the cradle movement, the work spindle is journalled directly in the work head. The tool head is provided with tools 12 which reciprocate to cut simultaneously opposite sides of a tooth of a gear blank G to which the rolling generating movements are imparted. The blank spindle is mounted in a work head 14 carried by a base 15 which is adjustable along arcuate guides formed on part of the cradle 16. The base 15 is provided with a guideway 34 along which slides a dovetail projection 32 on the work head, this adjustment, which serves to set the blank to the required cone distance, being effected by a pinion 37 and rack 38. The base 15 is secured in the required angular position on the cradle guides by means of bolts 40 and grooves 41. Oscillation of the cradle is effected by means of a cam which acts through a lever and link 25. In order to give rolling movement to the blank a segment 19 secured to a sleeve 18 engages with a stationary segment 20. When one tooth has been generated the tool head is withdrawn from the work and the work indexed by rotation of the sleeve 18 relative to the spindle. The segment 19 is made in two parts secured together by bolts 50 passing through slots and adjusted by a screw 52. The inner part of the segment is bolted to a sleeve 46 which is splined on the sleeve 18. In order to modify the profile of the teeth cut from the theoretical involute form the segment 19 is adjusted to an angle slightly different from the pitch cone angle of the gear blank. The adjustment of the segment 19 also enables a single segment to generate gears of different cone angles within a limited range so that the total number of segments required is reduced. The machine may also be set to cut gears similar to those cut on machines having geared rolling mechanism whereon the blank moves as though rolling on an imaginary nominal crown gear having a plane top surface (this nominal gear being represented by the tools) but the speeds of the rolling movement are arranged as if the blank were rolling on a true crown gear. The spindle is journalled directly in the work head 14 and is carried in a plain front bearing 26 and a gear ball bearing 27 both bearings being capped for ease of assembly. The spindle 13 carries a ratchet wheel 55 and an index plate 58, and the sleeve 18 carries an arm 61 to which is pivoted an arm 63 carrying a locking dog 65 which locks the spindle and sleeve together during normal operation. Slight adjustment of the work relative to the tools may be effected by a worm 68 which adjusts the locking dog along its arm. A lever 73 pivoted at 72 to the arm 61 is connected by a link 75 to the arm 63 and is provided with a cam surface 84 which normally engages a roller 85 on a pawl 81 to hold this pawl out of engagement with the ratchet wheel 55. Towards the end of the working roll a lug 87 on the work head engages a lug 88 on the lever 73 and moves the latter so that the locking-dog is withdrawn and the pawl is pulled by a spring 82 against the ratchet-wheel. The work-spindle is thus held stationary while the sleeve 18 and arm 61 continue to move so that the lug 88 rides off the lug 87 and the locking-dog engages with the next notch in the index place. During the backward roll the lug 88 rides over the lug 87 without lifting the lever 73. The machine is employed for the finishing operation, and in order to position the roughed-out blank a gauging device is employed. This comprises a ring 92 mounted over the front of the work-spindle and secured to the sleeve 18 by screws 102 and plate 101. The ring carries an arm 93 carrying on a pin 96 a plate 95 on which an arm 98 carrying the gauging-finger 99 is adjusted. The finger is adjusted relative to the tools so that it correctly engages a roughed blank. Any succeeding blank may then be correctly positioned by adjusting it on its spindle until the finger engages in a tooth space. When the finger is released it is returned to the position in Fig. 4 by a coiled spring 97.