Patent GB-332225-A (GB)
Title: Improvements in or relating to gear producing machines
IPC: B23F9/08
Filed: 1929-04-16
Abstract: 332,225. White, A. E., (Gleason Works). April 16. 1929. Gear-cutting.-In a machine for generating tapered gears, particularly by means of a taper hob which rotates in timed relation with the continuously rotating blank, a continuous rolling generating movement between the tool and blank is followed by a return rolling movement and the depth feed between the tool and blank is automatically effected during the first part of the rolling generating movement to bring the tool and blank into engagement. A two-speed drive is also provided so that non- cutting parts of the generating cycle may be effected at high speed. The machine, frame .10 is provided with ways for the tracks 11 of the tool cradle. The tool consisting of a taper hob H is mounted on a spindle 15, mounted in a holder 16 and is supported by an adjustable tailstock 17. The holder 16 may be adjusted about the vertical axis ofla shaft 20 to bring the tool into correct tangential relation with the blank and is clamped by a bolt 21. The: tool holder is in turn mounted on a swivelling head 19 which is adjustable about a shaft 53 to position the hob for cutting right or left hand spirals. The head 19 is adjustably secured to a slide 22 which is horizontally adjustable on a slide 23 which is in turn vertically adjustable on a standard 26. This standard can be adjusted horizontally on the cradle 12 in a direction at right angles to the direction of movement of the slide 22. These adjustments serve to position the hob in relation to the gear blank. The worktable 14 is angularly adjustable on the main frame by means of the usual curved rack 30 and is secured by bolts engaging a slot 31. A column 33, adjustably mounted on the table, carries a. vertically sliding work-head 35 in which the blank-spindle 36 is supported. The continuous rotation of the hob, and the corresponding rota. tion of the blank in unison therewith are derived from a motor 40 through the gearing shown diagrammatically in Fig. 10. The hob driving gear comprises bevel gears 41, spur gearing 43, shaft 45, bevel gearing 47, shaft 50, bevel gearing 54, spur gearing 58 and bevel gearing 60. The blank rotation is derived from the shaft 45 through spur gearing 66, bevel gearing 69, shaft 70, bevel gears 72, differential gear 74, shaft 75, bevel gearing 76, 82, shaft 84, spur gearing 88, bevel gears 91 and worm gears 95. For generating the tooth profiles, the hob cradle is givem a rolling move. ment and corresponding compensating movement is imparted to the blank. The generating movements are derived from the shaft 45 through bevel gearing 100, spur gears 104 and shaft 105 which imparts to a shaft 106 either a high speed drive through spur gears 108 or a low speed drive through bevel gears 111 and worm gearing 114. The high and low gears are selectively engaged by a clutch 118. The shaft 106 drives, through reversing-gearing 121, 124 a shaft 120 connected by spur gearing 127, shaft 129, bevel gearing 131 and worm gearing 134 to the tool cradle.The shaft 129 is also connected through bevel gearing 130 and spur gearing 139 to the casing of the differential 74 by which generating movement is superposed on the blank rotation. The twospeed shaft 106 is connected by spur gearing 150 and worm gearing 155 to a cam shaft 157 carrying cams 160, 161. The cam 160 controls the reversing-mechanism. 121, 124 through a lever operating a slide which connects the required gear to the shaft 120. The. cam, 161 operates the feed and withdrawal movements of the swinging table 14, being connected through a swinging arm with the rack member 30. The cam 161 also carries a pair of adjustable lugs 173, 174, the lug 173 coacting with a, roller on a pivoted arm 188 carrying a segment 182 engaging a segment 181 mounted on a rock shaft, 180 and secured to an arm 186 actuated by the lug 174. The shaft 180 is thus rocked in alternate directions during the rotation of the cam shaft, and these movements are effective to operate the change, speed clutch 118 through a link 191 and a quick throw-over device 200. Means are provided for automatically stopping the machine when a predetermined point on the return rolling movement is reached. This is effected by means of a dog 205 on the cradle which rotates a star wheel 206 and so operates a switch 207 in the motor circuit. On restarting the machine, the return roll is completed and the reversing mechanism operates for the working rolling movement. whereupon the machine is again reversed to return the parts to the initial position when the machine is stopped. The cams are so set that the slow speed is engaged only during actual cutting. The blank feed movement is made partly at the end of the return roll and partly at the beginning of the generating roll and the withdrawal movement is started towards the end of the generating roll and is completed at the beginning of the return roll. Specification 212,862 is referred to.