| 摘要 |
PURPOSE:To prevent a weld line from being formed on a part of a pull-ring opposite to a strut so as to increase the strength of the pull-ring, by changing the position for injecting a resin to a position opposite to the strut of the pull-ring from the central section of the plug. CONSTITUTION:When the plug A is injection molded that includes a double wall including an outer wall 1 and an inner wall 2, a partition wall 3 at the inner circumference of the intermediate of the inner wall 2 for intercepting the space, a circular score 4 in the undersurface of the partition wall 3, the strut 6 extending through a rib 5 from the top surface of the partition wall 3, and the pull-ring 7 on the top of the strut to be pulled up by finger, the position of a gate G through which a melted resin is injected into molds 10, 12 is displaced from the center of the plug as in the case of the prior art to the position of the pull-ring forming section 7a opposite to the strut. Consequently, the injected resin flows to both sides of the pull-ring forming section 7a, then the two flows join at a section 6a for forming the strut 6 of the plug A, and the resin flows to other part for forming the plug A. |
