GB884743A - Improvements relating to face mill cutters - Google Patents

Abstract

884,743. Milling-cutters. GLEASON WORKS. March 11, 1959 [March 27, 1958], No. 8437/59. Class 83 (3). A rotary tool for cutting a non- generated spiral bevel or hypoid gear G of tapering tooth-depth comprises a plurality of groups of cutter-blades 18a-19b, 18c-19d 18e-19e, each group presenting at least one inner and one outer cutting edge, the blades of each group lying along a different helix 21 coaxial of the cutter, and the helices being substantially identical and equally spaced from each other about the tool-axis 12. The tool cuts by the method described in Specification 750,034 and may be used in the machine of Specification 884,741. In the tool of Fig. 1, which is reciprocated in the direction of its axis three times for each of its rotations, the blades 18a-18e, 19a-19e are integral with mounting segments 13 attached by bolts 14 to a conical surface 15 of the tool. Keys 17 locate the segments 13. Adjacent blades cut on opposite sides of a tooth-space, and the offset (i.e. depthof-cut), of each inner cutting-edge is represented in Fig. 2 by a-e, a common helix 21 being assumed for purposes of illustration. Blade 18e cuts to full depth with its inneredge and blade 18d with its top-edge d<SP>1</SP>, extensions of these edges passing through the helix 21. Similarly (Fig. 3, not shown), the outeredge of blade 19e and the top-edge of blade 19d cut to the full depth of the tooth-space. Blades 18e, 19e are spaced so that they do not engage a tooth-space at the same time. Indexing of the gear blank takes place between the last group 18e, 19e and the first group 18a-19b. Offsets and blade-spacings for a finishing tool are given. In a modified three-stroke tool with separate blades, each having locating key and attachment screw (Fig. 5, not shown), the first blade of the first group has an inner cutting- edge while that of the second group has an outer cutting-edge. A four-stroke tool is also described, and a five-stroke tool in which one of the helices is without teeth, thus facilitating indexing of the gear-blank. The surfaces behind the cutting edges are preferably helicoidal, having a helix angle about six degrees greater than that of helices 21.