Patent GB-415583-A (GB)
Title: Improvements in or relating to gear lapping machines
IPC: B23F19/04
Filed: 1933-08-22
Abstract: 415,583. Finishing toothed gears. STEVENS, A. H., 5, Quality Court, Chancery Lane, London.-(Michigan Tool Co. ; 7171, Six Mile Road East, Detroit, Michigan, U.S.A.) Aug. 22, 1933, No. 23363. [Class 60.] Driving and feed devices.-A gear-lappingmachine for finishing gears has a number of gearlike lapping-tools 25 arranged around and meshing with the work 24, the plane of the gear being at an angle to the planes of the lapping-tools so that the lap teeth have different spiral angles from the gear teeth. The bed 11 is provided with a worktable 18 which reciprocates on ways 17, and a yoke 15 of inverted U-shape extends over the table and is bolted to the bed. The work arbor is mounted between a dead centre 22 carried by a fixed headstock, and an adjustable tailstock centre 23 which is slidable by means of a rack portion 48 engaged by a hand-operated sector 47. The lapping - tools 25 which may be of the same or different diameters or with modified tooth profiles, are mounted on arbors attached to hydraulic brake mechanism (not shown) each supported in a cylinder 27 mounted on an adjustable arm 28. The brake mechanism may comprise vanes or gears which build up a pressure which is indicated on a gauge 31 and is regulated by means of an adjustable escape orifice. The brake is effective for either direction of rotation of the arbor. A scale 32 is provided to facilitate the angular adjustment of the lap axes and the laps are adjusted radially of the gear blank along ways 33 by means of a screw 34. On the upper part of the yoke, the upper tool carrier and its brake mechanism are supported on ways 41 by means of a toggle 42 operated by a handle 43. When the toggle is broken the tool is moved upwardly by a spring to facilitate the removal and substitution of the workpiece. The gear blank is positively driven by a driver 60, Fig. 10, carried by a gear 61 connected through gear 59, shaft 52, and belt gearing 53 to a countershaft 80. A motor 65 is connected by a belt to a main shaft 68 which carries gears 81, 86 connected through an idler and directly respectively with gears 83, 87 on a shaft 84 for driving this shaft in opposite directions. The gears 81, 86 are selectively locked to the main shaft by clutches 85, 88 controlled by a lever through a rod 96. The shaft 84 is geared to the counter-shaft 80 which operates the work-rotating train. The main shaft 68 is also geared to a shaft 72 connected by a belt to a shaft 102 of the reversing and stop control mechanism 74, Fig. 5. The shaft 102 carries a gear 105 connected through a planet pinion 106 to a fixed annular gear 110 and a similar gear 111 having a slightly different number of teeth. In this way a slow differential movement is imparted to the gear 111 which forms an extension of a support 113 carrying adjustable reversing cams 100, 112 and stop elements 114. The reversing cams coact with a projection on the support of the reversing clutch control rod 96 to effect the reversals at the required times as determined by the spacing of the cams. After a predetermined number of reversals one of the stop elements 114 engages an arm 121 to operate an electric switch 124 to cut off current to the driving motor. For reciprocating the table, a gear 78 driven from the main shaft drives through a gear 128, a crank disc 129 whose pin is adjusted by a screw operated by a shaft 98. The crank pin is connected by lever mechanism to the table. In lapping a straight toothed gear the tool axes may be inclined to the blank at an angle equal to the angle of the tool teeth or they may be slightly inclined from this position to relieve the side edges of the teeth. A suitable lapping compound may be delivered to the tools during operation, or, if desired, the lapping compound may be omitted and a burnishing operation effected. In another modification, gear-like tools for taking a shaving cut in the manner described in Specification 392,385, [Group XXII], may be employed.