GB1110901A - A gear-shaping machine - Google Patents

Abstract

1,110,901. Gear-shaping. DRUMMOND BROS. Ltd. 31 March, 1967 [6 Jan., 1966], No. 728/66. Headings B3B and B3L. A gear-shaping machine comprises pneumatic or fluid-pressure means 15, 16, Figs. 1 and 2, for reciprocating the cutter on a cutting-stroke and means 30 for varying the speed of the cutting stroke without affecting the speed of the return stroke. A cutter head 3 and a slide 2 are moved together by fluid-pressure means 4, 5 and a relief movement is imparted to the head by similar means 7, 8. The cutter-spindle and work spindle 20 are rotated by gearing 21, 22 actuated by a fluidpressure device 23 or by a ratchet drive. In operation, the slide 2 is moved to the right by the piston 5 until a roller 11 engages a cam 10. The cutter is then fed downwardly by a piston 16. The first stroke may or may not remove metal. The cutter is relieved on the up-stroke by operating the piston 8 to withdraw the head 3 by a small amount. When the cutter has completed its up-stroke, the cam 10 is advanced by a fluid-pressure-operated rack to effect a feed increment, the cutter and work are rotated by the device 23 (which includes a double-acting rack-and-pinion and clutches which may be fluid-operated) and the head is returned to its former position by the piston 8. Feed and cutting continue until the slide 2 abuts an adjustable stop 12 or an adjustable stop on the slide abuts a fixed stop. The cam 10 may then rotate idly or stop. One complete rotation of the work follows to enable it to be finish-cut. The cutter head is then withdrawn by the piston 5, the cutter-reciprocating piston 16 is stopped and the cam 10 is returned to its initial position. The cam 10 may have several lobes to produce a stepped feed with pauses or may be rotated intermittently with pauses each allowing a complete revolution of the work to take place. It may be linear instead of rotatory. The speed of the piston 16 on a down-stroke is determined by the adjustable valve 30. This is by-passed by a valve 29 on the up-stroke. In a modification, the down-stroke speed is controlled by a variable-delivery pump. Backlash in the work- and cutter-drive may be eliminated by a gear connected to an hydraulic or an electric motor which may also be used for rapid movement for setting-up. To ensure rapid termination of cutting when all the teeth have been cut, an electric or hydraulic device is actuated, when the slide 2 engages the stop 12, to engage a clutch and connect a collar 50, Fig. 5, to the work-spindle. A spring tends to turn the collar in the opposite direction from spindle rotation. As the collar rotates with the work, a plunger 56 is forced out of a groove 54. When a dog 55 actuates a switch 59, say, after 360 degrees, the reciprocation of the cutter is stopped. Similar means can be used when the cutter pauses during its in-feed. In a modification, a disc 62, Fig. 8, is connected by a slipping clutch constituted by pistons 63 to a wormwheel 60 driving the work. When the stop 12 is engaged by the slide 2, a switch or valve actuates a piston to withdraw a tapered plunger from a recess in the disc 62 to allow it to rotate with the work. After 360 degrees rotation, a screw-head 69 actuates a switch to terminate cutting and re-engage the plunger. In further modifications, the cutter may reciprocate before the roller 11 engages the cam 10 or the work may be relieved instead of the cutter.