| 摘要 |
A shield for improving the wear resistance and life of holding support blocks for cylindrical carbide-tipped cutting bits used in drum pulverizer and wheel machines of the type used for pulverizing and cutting refractory materials is disclosed. The shield includes a short cylindrical metal container having a bottom annular wall supporting a coaxial central tube section. The annular space between the tube and inner surface of the cylindrical wall of the container contains and is hard brazed to solid tungsten carbide segments in the shape of sectors of a flat annular ring whose upper surface is parallel to the upper annular wall surface of the outer cylindrical wall of the container. The bore of the central tube is adapted to receive the shank of a cutting-bit, and the bottom wall of the cylindrical container of the shield is welded to the face of a cutting-bit holding block, with the bores of holding block and tube aligned, to permit insertion and removal of cutting bits into the bore of the holding block. In the preferred embodiment, the upper end of the tube is coined to flare radially outwards and downwards over the inner circumferential edges of the carbide segments, retaining the segments in place in the container. Preferably, the entrance bore of the tube is tapered to form a rotational bearing surface for the tapered lower annular flange of a cutting-bit.
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