Patent GB-976464-A (GB)
Title: Improvements relating to methods and machines for generating spur, straight bevel orlike gears
IPC: B23F5/20
Filed: 1963-11-20
Abstract: 976,464. Gear-cutting. GLEASON WORKS. Nov. 20, 1963 [Dec. 26, 1962], No. 45864/63. Headings B3K and B3L. Means for generating a gear G whose teeth extend substantially in planes containing the gear axis comprises a tool support 11 and a rotatable work support 15 mounted for relative generating motion including a rotation of the work-support, the supports also being mounted for relative advance and withdrawal depthwise of a tooth at a mean point of generation, and actuating means 32 for effecting relative withdrawal during the initial phase of generation (thus producing a reducing root relief on one flank) and advance during the concluding phase (thus producing an increasing tip relief on an opposite flank), the major portions of the tooth sides, however, being generated with the supports held against relative movement. The gears produced may be spur, straight-toothed bevel, or curved-toothed Zerol gears with the ends relieved and the middle portions of the profiles of substantially correct involute or octoidal shape. The intermeshing cutters C, C<SP>1</SP> and their supports are of the kind disclosed in Specification 772,237, but a single face-mill or reciprocating cutters may be used. The cradle 11 is rocked by a cam 29 rotated by a motor 23 and the transmission mechanism may be adjustable as described in Specification 934,131. The motor also rotates feed cams for moving the work-slide 19 and a cam 42 for reciprocating the work head 17 vertically. The latter may act through stroke-adjusting mechanism as described in Specification 870,879. Small angular adjustments of the cam 42 may be made by worm mechanism 47. The cams 29, 32, 42 all rotate at the same angular velocity. The motor 23 may also rotate the cutters. A follower 52, Fig. 3, is urged against the cam 32 by a piston 58 and is carried on a lever 51 adjustably pivoted to a rod 21 to move the work slide 19 between working and indexing positions. The cam 32 has two graduated, adjustable parts 82, 83 to allow independent adjustment of the extent of tip and root relief and adjustment of the pivot on the lever 51 varies the amount of relief. To move the work well clear of the cutters for unloading a piston 48 is moved to its right-hand position. For cutting a spur gear, the work-column 18 is adjusted so that the work axis 16 is at right-angles to the cradle axis 12, the generating cam 29 is removed and the cradle 11 is locked. The work-head 17 is then reciprocated past the cutters with the gear being continuously indexed by its uninterrupted rotation. For generating bevel gears, the column 18 is adjusted to the required angle and the cam 42 is removed. The cradle 11 is then rocked, the gear being cut on one of the cradle movements, the gear again being indexed by its continuous rotation. For generating bevel gears of long cone distance as in Specification 793,831, the cam 42 is used to reciprocate the head 17. The cutters may cut on both sides of a tooth space or, if planing cutters are used, on both sides of a tooth. Specification 870,819 also is referred to.