| 摘要 |
PURPOSE:To obtain a thin disc hand free from deflection, yet excellent in design, by arranging a monolithic electrocast shell construction which comprises a dial plate with a ring-shaped protruded frame on the circumference thereof and a hour pointer projected at the center of the dial plate. CONSTITUTION:The surface of a die is transferred onto the surface of a plastic matrix by a plastic molding. Then, a conducting film layer is formed on the surface of the plastic matrix by a chemical copper plating and nickel is electrocast thereon to form a nickel electrocast layer 25. Moreover, the undersurface side of the electrocast layer 25 is machined to define a shoe 4 of a hour disc hand 10 and the thickness of the disc hand itself 10 and after removed from the plastic matrix, the disc hand 10 is finish plated with gold or the like to complete a thin type disc hand 10. A hollow 26 is formed over the entire circumference of the rear of the disc hand 10 to create a shell construction. This reduces the machining cost after the electrocasting of nickel and allows the suppression of a deflection otherwise caused by machining. To prevent the deformation of the disc hand 10, a ring-shaped protruded frame 3 is provided on the circumference thereof.
|
