| 摘要 |
PURPOSE:To prevent generation of warp by almost uniformly bending the circumferential edge part of the disk serving as a basic board, thus reinforcing the disk. CONSTITUTION:As for a washer 5 and a dixk 1, one or plural through-holes or concave parts are formed on the disk 1, and the projection parts 7 for fitting purpose are formed on the washer 5, while setting their positions to the plural through-holes on the disk 1, and the projection parts on the washer are fitted with through-holes or concave parts on the disk, and the both are clamped under pressure by boss-caulking. Therefore, the center part of the disk is further strengthened, and thus perfectly flat disk free from the deformation in future can be held through the above works onto the bent circumferential edge and the center part of the disk. |
