Patent GB-481712-A (GB)
Title: Gear finishing machine
IPC: B23F19/06
Filed: 1937-06-21
Abstract: 481,712. Gear - cutting. FELLOWS GEAR SHAPER CO. June 21, 1937, No. 17265. Convention date, June 19, 1936. [Class 83 (iii)] A machine for finishing gears by conjugate gear-like tools such as those described in Specification 476,851 running in mesh with a work gear arranged on a non-intersecting and non-parallel axis has a reciprocatory carriage 14 carrying a rotary spindle 21 with a protruding portion on which the tool 33 (or work) is mounted, and a slide 43 supported on guides beneath the protruding part of the spindle and carrying at its upper end a holder 45 for mounting the work 32 (or tool). The spindle 21 driven from motor 22, Fig. 1, is mounted in a head 20 which is angularly adjustable on the carriage in arcuate guides 34 about an axis A which passes through the tool axis between cutters arranged as in Specification 476,851 and lies in a diametral plane of the work. This angular adjustment is facilitated by holes 41 in the carriage and slots 39 in the tool head. The work holder 45 is interchangeably secured to an upper flat portion 46 of the slide 43 and the slide is vertically adjusted by rotating through worm gearing, a nut 52 running on the screwed upper part 51 of a plunger 47 keyed in the slide. The lower part of the plunger carries a cam roller 49 engaging a cam 50 which automatically imparts vertical movement to the work. The latter, shown as an internal gear, is secured by an adapter to a carrier 61 mounted in ball bearings in the work holder. The carriage 14 is slowly reciprocated parallel to the work axis by a connecting rod 66 and crank disc 64 on a vertical shaft 68 connected to a motor 69 through belt gearing 71, worm gearing 73, shaft 76, worm gearing 77, change gears 80, 81 and worm gearing 84. A branch from the shaft 76 of this train, consisting of worm gearing 87, and change gears 89, drives the shaft 85 of the cam 50 at the same speed as the crank disc 64. In operation, the gear is finished in one to-and-fro movement of the tool and the cam 50, Fig. 8, may have a depression 91 (which withdraws the work when the crank is at its outer dead centre) and low spots at d, e. This produces a crowned or bowed formation of the teeth on the work similar to the formation of the tool teeth described in Specifications 466,330 and 476,851. The cam shown in Fig. 8 produces a convex bowed forma,- tion since the depth of cut is least at the centre of the teeth, but by using a cam having the rises at d and e a concave bowed formation may be obtained. For uniform teeth a circular cam with a single depression at 91 is used. The motors 22 and 69 are automatically stopped at the end of each cycle by a cam 92 on shaft 68 controlling motor 22 through switch 93 and a cam disc on cam 50 controlling motor 69 through similar switch mechanism. Either internally or externally toothed tools may be used and either internal or external gears may be finished. When the work piece is mounted on the spindle 21 this spindle must be set parallel to the path of the slide 14 as shown in Fig. 11. In this case the tool, shown as an internal gear 100, is mounted in a holder 96 which is mounted on the slide top 46 at the required helical angle. A number of interchangeable holders such as 45 or 96 may be provided and holes may be arranged in part 46 to facilitate mounting these holders.. Alternatively, a turntable may be provided to give the different angular adjustments for the tools or work pieces on the slide 43.