Patent GB-190724609-A (GB)
Title: Improvements in Gear Cutting Machines.
Inventor: EBERHARDT FREDERICK L HOMMEDIE
Filed: 1907-11-06
Granted: 1908-11-06
Abstract: 24,609. Eberhardt, F. L'H., and Zimmermann, W. F. Nov. 6. Milling.-Helical spur-wheels are generated by a hob which is fed, parallel to the wheel axis, across the face of the blank, the machine being constructed to operate without the use of differential gearing. The deduction and the application of formulµ connecting the various change-gears employed are given in the Specification. The driving-cone 57, Fig. 5, is mounted on a sleeve 54 secured to the framing, and is coupled to the shaft 52 by a flanged driver 58. The cutter 10, Fig. 12, is driven through reversing bevels 50, a vertical shaft 37, bevels 35, 34, Fig. 12, and spur gearing 17. The driven wheel 16 is confined laterally in the casing 25, but its splined centre 15 is adjustable, in this direction together with the spindle 9 to provide for varying lengths of hob. This adjustment is permitted by a slide 8 and is effected by a screw and lugs connecting the slide R and swivel base 4. The spindle 9 has a collar 18 and end thrust is taken by antifriction washers 21, 22. A flanged washer 24 excludes cuttings and dirt from the bearings. The saddle 3 is traversed on the pillar 2 by a feed-screw 126 driven from the shaft 84, which rotates the wheel flank, through a reversing train 117, change-wheels 121, and worm gearing 124. The wheel-blank arbor 112, Fig. 14, is secured in a conical bushing 110, by a differential nut 113, to rotate with a table 105, supported;near the axis and also at the rim. Antifriction washers are interposed at the former support. The table is provided with worm teeth 107 which are split to enable them to be more accurately formed. A pinion on the shaft 84 driven a pinion on a sleeve loose on the shaft of the worm 95 but adjustably connected to it by a worm and wheel, so as to give a solid drive and yet permit of adjustment. The shaft 84 is driven from a shaft: 64 through a compound train of change-gearing 82. The changegearing 82 is adjusted so that the relative rotation of the blank and hob differs slightly from that corresponding to an engaging worm-wheel and worm, and the change-wheels 121 are such that the travel of the feed-slide just produces the required inelination of the teeth. The shaft 64 is driven from the shaft 52 by worm gearing 61, or in the reverse direction at an increased speed by spur and bevel gearing 135, 73. After taking a cut, the blank is disengaged from the cutter and a clutch 70 is manually operated to throw in the quick-return drive for the cutter slide. To permit of this reversal and the re-engagement of the cutting-feed without losing the synchronism, the clutch is constructed to allow engagement in one relative angular position only, and the various gear ratios are such that the shaft 52 makes an integral number of revolutions per revolution of the cutter shaft 9, and the shaft 64 when driven through the gearing 61 makes one revolution for each revolution of the cutter shaft. The feed-screw 126 is driven through a clutch which may be operated by hand or by a dog rod 130. In a modification, the cutterslide feed-screw is driven from any constantly rotating shaft between the cone 57 and the indexing-gears 82.