| 摘要 |
PURPOSE:To dispense with the application of special processing to a hard core material, by integrally coating the outer peripheral surface of a shape holding core material, which is molded into a shape near to a middle case to be molded, with a thermoplastic resin having elasticity. CONSTITUTION:A thermoplastic resin material 1 having elasticity is applied onto a middle core material for reinforcing a middle, which is molded from a metal or a hard resin material and receives finish processing in the threaded part 26 of its parting surface 24 and its back surface, so as to cover not only the outer surface thereof but also the placing surface 21 of glass 3 and the reverse surface 22 thereof and the coated parts are formed into a glass packing 11. In addition, the lower end surface of the core material 2 is also coated with said resin material 1 to form the closely adhered connection part 12 with the peripheral edge 41 of the back surface 4. By this method, the numbers of processes and parts can be reduced to a large extent without applying special processing to the hard core material. |
