| 摘要 |
PURPOSE:To stabilize the pressability, fixing force, etc. of a back cover by providing plural gnawing dowels which project outward in one piece at >=2 places in the upper part of the outside circumferential rising part of the circular back cover having one or plural prying-to open parts in the outermost circumferential parts. CONSTITUTION:A packing 3 for maintaining waterproofness is mounted to a back cover 1 and dowels 1a are provided in one piece to a number of places in the upper part of the outside circumferntial rising part 1b of the cover 1. Said dowels 1 are gnawed to the gnawing groove 2a of a case band 2. Here, the cover 1 is beforehand formed into the shape relieved of the part projecting to the bore of the case band, a button part or a crown part, and movement projecting parts. Then, a finished product is obtained by the easy working involving blanking and drawing alone, there are no problems in appearance, costs are considerably lower on account of saving of working and deburring, working is easy, quality is stable and the back cover of mass productivity is obtained. |
