| 摘要 |
PURPOSE:To enable injection molding of parts with a complicate shape having a half-closed undercut, by forming the shape of a mold for an undercut of a molding by using a sliding core and a rotating core when a mold is closed. CONSTITUTION:A half-turn pot 1 has an undercut 10 in an internal periphery of a side wall 3. By properly designing gears 35 and 38 and racks 36 and 42, it is possible to move a sliding core 23 and a rotating core 25 independently from each other when a mold is opened, said cores 23 and 25 cooperating to form the mold for the undercut 10. When a mold is opened after injection molding of a resin, a resulting molding, or the pot 1, remains attached to an annular core 30 of a movable half 21 of a mold, while the sliding core 23 and the rotating core 25 retreat from the undercut 10 of the pot 1, respectively by receding and by rotating. The pot 1 can be taken out by pushing it up with a knockout bar 33 after the mold is opened. |
