Patent GB-821511-A (GB)
Title: Improvements relating to rotary cutting or abrading tools
Inventor: HALL GODFREY NEWMAN
IPC: A47J17/18
Filed: 1956-12-21
Abstract: 821,511. Milling-cutters. SIMMONDS AEROCESSORIES Ltd. Dec. 16, 1957 [Dec. 21, 1956], No. 39113/56. Class 83 (3). [Also in Group VI] In a rotary cutting or abrading- tool wherein the cutting-area is provided by thin flexible strip or sheet B of hardenable metal having a multiplicity of holes 10 therein and hard, sharp cutting-edges 11 upset from the strip or sheet along a series of parallel lines, each cutting-edge being constituted by portions of the edge of a hole 10 and having a clearance-angle, the cutting-area is divided into a series of cutting-sections 4 and the cuting-edges are so directed as to cut when the tool is rotated in one direction only. The whole of the strip or, as illustrated, only the cutting-sections 4, are provided with the cutting-edges 11. The strip is folded, along lines 1, 2, into annular form, Fig. 2, before the edges are hardened by a cyanide or gaseous diffusion treatment of the whole element. A dished supporting-element of sheet-metal (Fig. 3, not shown), to which at least some of the non-cutting intermediate sections 6 are spot-welded, completes the tool and provides a stubshaft for rotation of the tool. Instead of the edges 11 being in a flat plane, they may be formed on the inclined surfaces 6, and a flat support spot-welded to the sections 4. An uninterrupted cutting-area may be provided from a strip, the whole of which has cutting- edges 11, by tapered folds 20, Figs. 4 and 5, the parts 5, 7 of which are pressed into engagement with each other, flattening the ridges 12 locally. The folds 20 may be secured to turned-up radial-tongues on a support, or at least some of them may be welded in radially-aligned notches, as in the construction of Fig. 11, described below. Alternatively, the folds may be given a triangular cross-section (Fig. 7, not shown), having a flat base by which they are spot-welded to a support. Instead of folding the cutting-sections from a cutting-strip, they may be severed therefrom and provided with flanges 27, 28, Figs. 8 and 9, spot-welded to polygonal rings 30, 31 to form a unitary cutter which is secured, as by bolts 35, to the flanges 33, 34 of a support 32 perforated to permit the escape of swarf. By varying the width of the rings 30, 31, the cutting-area may be made approximately conical. The support 32 may be made from sheet-metal (Fig. 10, not shown), having an outer flange and an inner series of spaced tongues replacing the flange 34. The cutting-area may, alternatively, be discontinuous. As depicted in Fig. 11, radial or parallel flanges 41, 42 may be formed on the separate cutting-sections 40 for brazing or welding in slots 44 in a support 43 of conical cross-section, which locates the cutting-edges in a flat plane. A sheet-metal support may be used in place of the support 43. Tools of conical form or double curvature may be provided, e.g. part-spherical or the like, as illustrated in Fig. 15, which depicts a butt, the curved sections 50 of which are attached to discs 51, 52 welded to a shaft 56. The sections may be joined by folds, as in Fig. 5. Non-cutting margins of the cutting-area may be avoided by providing cutting-edges 11 intersecting the edges of the area, as in Specification 821,510. Specifications 666,573, 666,621, 666,622, 695,830, 695,859 and 721,895 also are referred to.