| 摘要 |
PURPOSE:To prevent occurrence of any sink by forming slip-out preventing ribs composed of at least 2 ribs small in width. CONSTITUTION:A spool is provided with the slip-out preventing ribs 15 made smaller in width than the conventional slip-out preventing ribs by about 1/3. These ribs 15, 15 are located between engaging ribs 8, 8 so as to set the distance between the both outsides similar to that of the conventional slip-out preventing ribs, and the ribs 15, 15 are shortened in side width and they are arranged side by side, thus permitting injection time and cooling time to be reduced without causing any sink in the injection molding process for manufacturing the spool, and its cost to be lowered by enhancing its productivity. |
