Patent GB-680104-A (GB)
Title: Improvements in machines for producing gears
IPC: B23F23/12
Filed: 1948-07-06
Abstract: 680,104. Gear-cutting and grinding. GLEASON WORKS. July 6, 1948 [Oct. 15, 1947], No. 18185/48. Class 83 (iii). [Also in Groups XXIV and XXV] A machine for producing tapered gears with longitudinally curved teeth comprises an annular cutter C, Fig. 22, secured to a spindle 55 mounted on a support 40 and adjustable about an axis W intersecting the spindle axis t in a point a in the plane of the tip of the cutter. The cutter, which may be a face-mill cutter or a grinding-wheel, may thus be adjusted angularly to represent a form-cut tapered gear or a crown gear or to cut gears having pressure angles equal to or differing from those of itself. The blank G, Fig. 2, is mounted on a column 2'80 slidable on a member 420 pivotally mounted on a slide 425 for adjustment of cone distance and cone angle, the latter being measured by a scale 428. A bar 370 on the slide 425 is pivotally connected to a hydraulic piston 368, Fig. 15, which, when the machine has been set up, is moved by a lever 372, Fig. 3, to advance the blank to operative position. An electric motor 70, Fig. 19, is then started to feed the blank into the cutter. At the same time the blank and cutter are rotated and a cradle 35 carrying the cutter is rocked to generate a tooth-space. After rocking in one direction, the cutter is returned either in, or out of, contact with the blank and the blank is then indexed by one tooth space. When all the teeth, or one side of each tooth, have been generated, a cam-operated electric counting device stops the machine. The hydraulic piston 368 is then actuated again to move the blank to the unloading position. Cutter-spindle-mountings.-The cutter C, Fig. 4, having a trueing disc 62, is mounted on a spindle 55 journalled in a carrier 50, rotatably adjustable about an inclined pivot 120 in a head 45. The head 45 is rotatably adjustable about an eccentric axis in a drum 40 which, in turn, is mounted eccentrically in the cradle 35 carried in a housing 31. Manually-turned shafts 207, 194 and 192, Fig. 3, and graduated scales are provided to adjust the members 40, 45 and 50. The cutter-drive from the motor 70 includes gearing mounted on the axes of the rotatablyadjustable members. The motor 70 also drives a shaft 206, Fig. 19, which rotates a barrel cam 150 once per tooth side or sides. The cam 150 comprises three grooves 151-153. One of two followers is moved by a manually-turned pinion 348, Fig. 15, to engage one of the grooves 151 or 152 according to whether a finishing or roughing cut is to be taken. The followers are mounted on a lever 345 pivoted at 350 and connected to the cylinder 363 of the hydraulic piston 368 by a block 360 sliding in a slot 361. The piston 368 is locked in its cylinder by hydraulic pressure so that rotation of the cam 150 reciprocates the slide 425 to move the blank to and from the cutter. The effective throw of the lever 345 is adjusted by a screw 357 engaging a nut 358 pivoted on the block 360. Wear of the cutter is taken up by a hand-screw 530, Fig. 2, which adjusts the length of the bar 370. The groove 153 is engaged by a follower 160 which oscillates a gear sector 170 connected to the cradle 35 by hypoid gearing 188, 190. The groove is shaped to cause the cutter to provide evenly-spaced cuts, or generating flats, along the whole of each tooth face. The sector gear 170 also rotates a shaft 232 which drives the blank G through a differential gear 240-242 and hypoid gearing 307, 308. Removable gears 181, 183 allow the oscillation of the cradle 35 to be reversed and change-gears 225, 226, 230 and 231 allow the ratio of roll to be varied. The cutter-drive is transmitted from the housing 31, Fig. 2, to the column 280 via a sliding shaft 265 and bevel gearing in pivoted casings 260, 274. Change-gears 293, 294, 297 and 298 in the drive are adjusted according to the number of teeth to be cut. Chucks.-The blank G is mounted on a shaft 310, Fig. 18, in a chuck actuated by a screwed draw-spindle 325 operated by hydraulic and/or spring means. The shaft 310 is journalled in a bracket 315 adjustable vertically by a handturned screw 322, having a co-operating setting dial 321, to set the gear blank when cutting hypoid gearing. Machine framings.-The slide 425, Fig. 2, on which the work is fed towards the cutter, is mounted on rollers 432-434, Fig. 3, carried on a sub-base 32 which is pivoted at 435 to the machine-bed 30 and is adjusted angularly against a zero 438 when a grinding-wheel is employed. By such angular adjustment, uniform wear of the grinding-wheel may be achieved. The column 280 is adjusted along the member 420 by a rack secured to its underside and is locked in position by T-bolts engaged by nuts tightened manually through toothed gearing (see Group XXV). Indexing.-The drive to the cam 150, Fig. 19, also rotates an indexing member 391, Fig. 8, which is coaxial with two disc cams engaged by rollers controlling the movement of a locking member 407. The member 391 carries a roller 396, which engages one of two slots in a disc 402, and also a gear segment 395 which engages a similar segment on the disc 402 to provide a positive, even drive during the main indexing movement. Rotation of the member 402 is added to the differential gearing 240-242, thus indexing the blank through one tooth space. Gear teeth-relieving from theoretical shape. In a modification, a rotary cam adds increments of rotation to the cradle 35 by way of a differen-. tial gear, not shown, inserted in the shaft 182, Fig. 19. The shape of the teeth and the pressure angle may thus be varied according to the shape of the cam. Specifications 543,408, 546,494 and 680,183 are referred to.