| 摘要 |
PURPOSE:To reduce a manufacturing cost, by a method wherein a cover sheets, covering the back of a case body, a side wall, standing upright from a periphery thereof, and a cover plate elementary material, which has a projection protruding to the inside of the cover plate and at the base part, are monolithically formed through a thin metal sheet. CONSTITUTION:A thin stainless sheet, which has been ground, is punched to form a cover sheet 2 for covering the back of a case body 1 for a wrist watch, and simultaneously, a drawing process is made on the periphery of the cover sheet 2 to form a side wall part 3 standing upright from the periphery of the cover sheet 2. When the drawing process is conducted, a press processing, simultaneously, is made on the base part of the side wall part 2 and on 8 spots spaced at equal intervals to dent the outer surface of the cover sheet 2 to form projection parts 4 protruding inward, and this manufactures a back cover elementary material 5. An ineer sheet 7, a hook peripheral part 14, and a middle frame 15 are attached to the back cover elementary material 5 to unite them into a monolithical unity to complete a manufacture. This reduces the number of processes and a manufacturing cost compared with conventional manufactures. |
