| 摘要 |
PROBLEM TO BE SOLVED: To prevent a sinkmark from developing on a surface opposite to the boss part, to which the fusion welding part of a molded article is formed, realize larger diameter boss part and consequently a wider fusion welding range, a remarkably higher impact strength, a fine fusion welded surface and a favorable appearance and contribute to the improvement of quality. SOLUTION: This article is produced by integrally binding the fusion welding parts corresponding respectively to the upper case 1 and to the lower case 2 made of synthetic resin members. On the inner surface of one synthetic resin material lower case 2 at its welding part position, hollow tubular boss parts 3 are protrusively provided. Through holes 4, through each of which the boss part 3, are provided opposite to the welding part positions of the upper case 1 made of the other synthetic resin member and then each boss part 3 is fittingly and projectingly connected to the through hole 4 by abutting both the synthetic resin members against each other so as to form the end 31 of the boss part projecting beyond this through hole 4 into the fusion welding part 5 of a curved surface-like ring flange part larger than the outer diameter of the through hole 4 in order to bind the upper and the lower cases 1 and 2 together. |
