| 摘要 |
1,247,532. Moulding grinding wheels. SUPER-CUT Inc. 9 Dec., 1968 [13 Dec., 1967], No. 58321/68. Heading B5A. [Also in Division B3] A method of making an internally reinforced continuous annular grinding member comprises the steps of providing an outer mould wall 50 having a continuous annular inner surface, providing an inner ring-like metal mould wall 16 having a continuous outer annular surface of less overall diameter than the overall diameter of the inner surface of the wall 50, positioning the mould walls so that said inner and outer surfaces are concentric and define therebetween an annular mould cavity 60, filling the cavity with a mixture of fusible powder and abrasive particles, creating an atmosphere of heat in the vicinity of the mould cavity to heat the mixture and the mould wall 16, and applying outward radial pressure to the wall 16 to expand it uniformly and by a stretching operation increase its circumference, thus compressing the mixture in the cavity 60, fusing the powder, and heat bonding the latter to the outer surface of the wall 16. Apparatus described for carrying out the method includes a pair of cam rings 22, 24 having frusto-conical surfaces 26, 28 which engage co-operating surfaces on the inside of the mould wall 16 so that when the cam rings 22, 24 are urged towards each other by a press 52, 54 the said radial pressure is applied to the wall 16. The heat is applied to the powder mixture and wall 16 by a gas burner 64. The wall 16 may be of steel and the cam rings 22, 24 may be of metal, e.g. steel, so that after the insertion of solder or brazing material between the cam rings and the wall 16 and the urging together of the cam rings the cam rings are bonded to each other and to the wall 16 to form a three-part hub for the grinding member. Alternatively the wall 50 and cam rings 22, 24 are of graphite and the cam rings do not bond to the wall 16. The cam rings may include radial flanges 36 which apply lateral pressure to the mixture in the cavity 60. The inner surface of the wall 50 may be planar, as shown, concave, or convex in section. The fusible powder may be metal or vitreous powder, and the abrasive particles may be of diamond, tungsten carbide, silicon carbide, or fused alumina. |
