Patent GB-348867-A (GB)
Title: Gear generating machine
IPC: B23F5/16
Filed: 1930-05-06
Abstract: 348,867. Gear - cutting. SIMMONS, O. G., 17217, Clifton Boulevard, Lakewood, Ohio, U.S.A. May 6, 1930, No. 13963. [Class 83 (iii).] In a machine for generating spur gears, particularly helical gears, the gear blank and a reciprocating pinion cutter are continuously rotated in timed relation and the cutter is fed progressively in a lateral direction parallel to an imaginary rack engaging the blank, the feed movement being compensated by modifying the cutter rotation in such a manner as to maintain correct generating relation between the cutter and the blank. The blank axis is set over to the required helical angle with respect to the cutter axis and helical gears of all angles may be cut from a single straight tooth pinion cutter. Thus in Figs. 7 and 9 a cutter 32 reciprocating along the axis a a and rotating in timed relation with the blank 17 is fed laterally along the imaginary conjugate rack, between the dotted and full line positions in Fig. 9. The corresponding settings for the cutting of helical gears are shown in Figs. 10 and 12. The machine comprises a base 1 having a portion 2 carrying an adjustable workhead 4, the angular adjustment of the workhead being indicated by vernier scale 5. Adjustment is effected from a squared shaft 201 connected by bevel gears 200, Fig. 21, to a shaft having pinion teeth 195 engaging a circular rack 193. The workhead is clamped by bolts 4a and is provided with a vertically adjustable spindle head 9 secured by bolts 10. The head carries a work-spindle 11 which is provided with a conical seating 18 in which the arbor 16 carrying the blank 17 is secured by a bolt 19. An overhanging arm 12 carries a tail centre to support the outer end of the work arbor. The work-spindle is mounted on ball bearings 149, 150. The base 1 is also provided with horizontal guideways for a support 23 on which is mounted a transversely-movable carriage 27 having laterally-aligned trunnion bearings which receive trunnions carried by a head 30 providing a rocking support for the cutter spindle 31 carrying the pinion cutter 32. The forward end of the cutter spindle is mounted in a slide 33 having longitudinal movement in the head 30. The cutter is reciprocated in a fixed horizontal plane, the adjustments for different sized blanks being effected by moving the workhead. The driving mechanism of the machine is shown diagrammatically in Fig. 13. An electric motor 34 is connected by a chain 39 to a shaft 35 which carries a pulley 40 driving an oil pump 44. The shaft 35 is connected through change gears 46, shaft 47, change gears 48 . . 52, shaft 53, worm gearing 54, vertical shaft 56, bevel gears 58, shaft 59, bevel gears 60, vertical shaft 62, splined bevel gear 63, shaft 65, and worm gearing 67 to the work-spindle 11. The axis of the shaft 56 is the axis about which the workhead is adjusted. A bevel gear 68 on the shaft 47 drives through a shaft 70, change gears 71, telescopic shaft 73, worm gear 74, shaft 76, spur gears 77, 78, 80, shaft 81, spur gear differential 88, telescopic shaft 91, and worm gearing 93 to the splined cutter spindle 31. The change gears are so arranged that the cutter and blank are rotated in correct timed relation. The worm wheel 75 carries an adjustable crank pin 94 which, through the linkage shown in Fig. 13, reciprocates the slide 33 to impart axial reciprocating movement to the cutter. The transverse feed movement of the cutter carriage is effected by means of a lead screw 101 engaging a nut 102, and rotated by ratchet mechanism 104, 106 actuated automatically from an eccentric 372 mounted on the shaft 76, Fig. 23, and connected through a link 371, Fig. 30, and slotted lever 366 to a ratchet-operating arm 364. The lead-screw may also be rotated manually by a crank applied to its squared end 103. The screw is connected through spur gearing 107, worm gearing 112, bevel gears 114, change gears 117, and spur gears 122, 125, to the planetary carrier 87 of the differential gear, this gearing serving to compensate the cutter rotation for the transverse feed movement of the cutter carriage. The change gears in the various driving trains are mounted within housings such as 126, the housings being provided with hinged doors for convenient access. The base 1 is also provided with a hinged door giving access to the motor 34 and oil pump 44. The vertical adjustments of the workhead are effected from a squared shaft 147 which is connected by spiral gears to the adjusting screw 138. Fine adjustment is facilitated by a graduated dial 148. The transverse worm shaft 65, Fig. 19, is mounted in a supporting member provided with ball bearings 158, 159, the supporting member having an extension 160 provided with ball bearings for the hub of the splined bevel gear 63. The supporting member is adjustable by means of a screw 167 to permit the adjustment of the worm 66 relatively to its worm wheel. The mountings for the shafts 56, 59 in the work-driving train are shown in Fig. 20. The gear housing 126, secured to the slide 23 by brackets, supports one end of the shaft 76, the other end of this shaft extending into the housing 128 also secured to the slide 23 as shown in Fig. 23. The crank pin 94 from which the cutter is reciprocated is adjusted on its worm wheel 75 by means of a scale. The base frame is slotted at 254 to permit longitudinal adjustment of the slide 23 with the shaft 76 and its housings. The worm shaft 91 which is carried by the transverselymovable head 27 has a splined extension extending through the splined tubular shaft 90, and the shaft 91 is mounted in a carrier 277 bolted to the trunnions 29, 29a. The housing 30 enclosing the worm 92 and its worm wheel is adjustable on the member 277 bv means of a screw. The shaft 91 is in alignment with the trunnion axes so that the transverse movement of the carriage 27 may be effected without disturbing the drive of the shaft 91 from the splined shaft 90. The rear end of the cutter spindle is keyed to a sleeve 297, Fig. 25, which is slidably keyed in an elongated hub 299 of the worm wheel 93 by means of diametrally opposed gibs 298 arranged in pairs as shown in Fig. 35. The gibs are held in place by bolts 305 passing through clearance holes in the hub 299 and are moved outwards to compensate for wear and to bring them into close engagement with the sides of their respective grooves by means of wedge elements 396 adjusted by means of bolts 397. The cutter slide 33 is connected to the link 100 by means of a bracket 313 and the housing 30 has a forwardly extending channel 315 which coacts with upper guideplates 316 to guide the cutter slide. The extension 315 has slight vertical play in the carriage 27, the upward movement being limited by stop bars 319 and the downward movement by flanges on the carriage 27. Springs normally tend to hold the extension in its lowermost position. In operation, during the forward operative stroke, the cutter is held up against the stop bars by means of a cam 330 splined on the shaft 76, the cam being connected through levers 336, 338 to a rounded thrust link 339 engaging under the forward end of the cutter housing. On the return stroke the cam 330 allows the springs to move the cutting housing downwards, thus relieving the cutters from the work during the idle movement. A wedge 342 in the link mechanism may be adjusted to determine the upward pressure on the housing during the cutting stroke. Means are provided for automatically disengaging the ratchet actuating pawl 105 after the desired lateral travel of the cutter carriage. For this purpose an arm 373, Fig. 30, carries a pin engaging a spiral groove 377 in the ratchet wheel 106. The pin may be adjusted to any part of the groove at the start of the operation and after a predetermined feed the inward movement of the arm along the spiral causes a shoulder 374 on the arm to engage with a pin 375 on the pawl to disengage the latter from its ratchet wheel. During the operation of the cutter, a suitable nozzle, not shown, is provided for directing a stream of lubricant over the cutter, the lubricant being directed into a spout 399 moving with the carriage 27, by a flange 401 on the housing 30. The spout 399 delivers through a strainer into a stationary spout 402 communicating with a receptacle 403 connected to the pump 44. The pump has a delivery pipe 405 which is fitted with a tap 407 so that the receptacle 403 may be drained when necessary.