Patent GB-1018222-A (GB)
Title: Improvements in or relating to the treatment of workpieces in the manufacture of articles of ceramic ware
Inventor: DOWLEY ARTHUR
IPC: B24B9/06
Filed: 1961-11-01
Abstract: 1,018,222. Grinding. SERVICE (ENGINEERS) Ltd. Nov. 1, 1962, Nos. 39034/61, 24795/62 and 28876/62. Heading B3D. The invention relates to several different features of a machine for finishing a circular article of ceramic ware including the support of the workpiece by a suction device while towing, and the use of a rockable and indexable fettling tool for finishing the edge of the workpiece. A number of supports 38, Fig. 3 (not shown), are arranged on the ends of arms 36 of a spider which is indexed to move the workpieces successively between a loading station, an operating station and an unloading station as described in Specification 1,018,221. Each support comprises a disc 44 which is rotatably mounted on the end of an arm 36 and has a strip 50 of cellular material around its periphery for receiving the marginal portion of the workpiece. The strip has three gaps, in each of which is a suction device comprising a cup 58 having a flange 54 engaging a base 56 on the disc, and a tube connected by passages 62 to a space 46 connected to a suction pump as described in the above-mentioned Specification. The operating station 34, Fig. 1 (not shown), has two shafts 64, 108 forming parts of a towing device 40 and a fettling device 42. The towing tool, which is described in Specification 1,013,419 and comprises at least one strip of flexible abrasive material extending over at least the radius of the workpiece and reciprocated through a small amplitude, is carried by a shaft 64 having fixed thereto a collar 72 provided with rollers 80 engaging the bifurcated end of a lever 82 which is movable by a cam to raise and lower the towing tool into and out of engagement with the workpiece. The shaft 64 carries a roller 90 which cooperates with a bell-crank lever 92 joined by a rod 100 to a crank 106 on the shaft 108 carrying the fettling tool which is thereby, simultaneously with the movement of the towing tool, brought into engagement with the edge of the workpiece. The shaft 108 is rotatably mounted in a support 110 vertically slidable in a bracket 112 by a manually-operable screw 114 having a handle 124 to adjust the fettling tool to the height of the edge of the workpiece, the towing tool also being vertically adjustable by a handle 68. The lower end of the shaft 108 carries a housing 148, Fig. 5 (not shown), and a rod 136, which is movable by a bell crank 128 rockable by a rod 134 co-operating with a cam, is connected by an adjustable link 140 to a crank 144 on a shaft 146 rotatable in bearings 150 in the housing 148. The end of the shaft carries a cranked member 164 supporting the fettling tool 166 which is rocked during abrading of the edge of the workpiece between angular positions 30 degrees above and 30 degrees below the horizontal plane by movement of the rod 134; a dwell may be provided in the horizontal position of the fettling tool to ensure complete removal of any flash present on the edge of the workpiece. The fettling tool 166 comprises a strip of emery cloth on a sponge rubber strip bonded to a disc 174 connected by a one-way clutch 170 to the member 164. During abrading, the rotation of the workpiece holds the tool against the one-way clutch to prevent rotation of the tool. After an abrading operation, as the tool is swung out of engagement with the workpiece, a portion 184 of the tool engages a pad 186 which causes the tool to be indexed a small amount so that a fresh part of the tool is presented to the next workpiece. In an alternative embodiment, the fettling tool comprises an abrasive stone which is bonded to a flexible pad on the end of the member and has a curved surface for engaging the edge of the workpiece.