Patent GB-1474717-A (GB)
Title: Apparatus and method for grinding an elongated workpiece
IPC: B24B5/04
Filed: 1974-12-16
Abstract: 1474717 Grinding H A McMASTER 16 Dec 1974 [19 Dec 1973 1 April 1974] 54179/74 Heading B3D Apparatus for grinding a roller blank 12 from its rough diameter 23 to a predetermined finish diameter 26 comprises at least one grinding wheel 48, means for rotating the blank about its axis w, at least one centring support member 32 for supporting at least one end of the blank, the or each member having a head portion 34 and a shank 30 for insertion in an axial bore 28 in the, or the respective end of the blank, a centring 0-ring 42 mounted on the shank, or each shank, intermediate the ends thereof for engaging the wall of the, or the respective, bore, and an elastic drive 0-ring 44 disposed on the, or each, shank adjacent the respective head portion, the drive 0-ring being of a diameter in excess of the respective bore and the centring 0- ring but smaller than that of the, or the respective, head portion for frictional driving engagement with the, or the respective, end of the blank.  As described, the roller is for use in conveying glass through a furnace and is of ceramic material, the ends of the roller being of slightly reduced diameter to receive metal caps from which project supporting pins. The roller blank of ceramic material, bush as fused silica or glass rock, has an initial rough diameter 23 and an axial bore 28 at each end. The central portion of the roller blank is ground to a finish dimension 26 and the end portions to a finish dimension 24 to receive the end caps. One bore 28 receives the shank 30 of a support member 32 having a head portion drivable by a chuck, and the other bore receives the shank 36 of a support member 38 having a head portion 40 formed with a conical recess 46 for engagement with a tailstock centre. Grooves 43 in the shanks 30, 36 locate the elastic centring 0-rings 42, 43, which engage the walls of the bores, and the elastic 0-rings 44 are disposed between the head portions 34, 40 for frictional engagement with the end walls 45, 47 of the roller blank. The grinding wheel 48 consists of a disc having a V-shaped periphery of abrasive, such as a diamond matrix, the V preferably having an included angle 2y equal to 60 degrees and the plane of the wheel being at an angle y to the axis w of the roller blank so that one face 56 of the periphery acts with an undercut to rough grind the roller blank and the other face 58 acts to finish grind the blank. The effect of the undercutting is stated to cause a cancellation of radial forces 66, 68 of the blank so as to minimize transverse bending-forces acting on the blank during grinding. In another embodiment, rough grinding with undercut is effected by a grinding wheel 100, Fig. 6, on one side of the roller blank and finish grinding is effected by a second grinding wheel 101 which trails the first and is disposed on the other side of the roller blank. The first wheel has a hub portion 102 with a radially extending rim 104 having grinding surfaces 106, 108, and the second wheel has a hub 114 having a grinding face 118 with an inclined portion 120, the operative portion of which is parallel to the axis w of the roller blank.