| 摘要 |
621,227. Grinding and polishing; polishing discs. HOOP, H. DE. Dec. 24, 1946, No. 37911. Convention date, Jan. 28, 1944. [Classes 19 and 60] The face of a disc 1 is clothed with a sheet 2 of sandpaper, flannel etc.; the face of the disc has a conically bevelled portion 3 in which is provided, as e.g. by turning a groove 4 to receive the edge of the sheet; the face 5 of the marginal portion of the disc lies behind the front face of the sandpaper. |
