| 摘要 |
PURPOSE:To simplify the device, shorten the processing time, and reduce the costs of grindstones by coaxially installing a grindstone for the inner circumference and a grindstone for the outer circumference on a single rotational shaft in a device for processing the inner and outer circumferences of the doughnut shape plate-like article. CONSTITUTION:When a donut-shaped glass plate used for an optical disk, etc., is produced, a glass disk is cut down into a donut-shaped piece, and the inner and outer circumferential surfaces of the piece are subjected to a chamfering processing and to an edge surface-processing, respectively. Therein, the donut shape glass disk 36 is attracted onto the surface of a table 32 with a vacuum-attracting means. The processing tool 34 is provided with a shaft 38, and a device 30 for processing the inner and outer circumferences of the disk is rotatably supported on an axial line. The shaft 38 is supported liftably in the axial direction and transferably in the radial direction of the donut shape plate 36. The grindstone 40 for the inner circumference contains a circular groove 40A, and both the walls 40B are formed in tapered states. The grindstone 40 for the inner circumference can be fit into the glass disk 36A. The grindstone 42 for the outer circumference is installed above the grindstone 40 for the inner circumference. |
