| 摘要 |
PURPOSE:To prevent a foaming material certainly from flowing backwards by a method wherein a head is enabled to leave from a metal mold just after injection when the foaming material is injected into a cavity of a closed die. CONSTITUTION:In a metal mold for closed injection which pressure injects a foaming material into a cavity 16 by making a head 22 abut against a sprue 20 formed on a parting face between a top force 14 and a bottom force 12, a rod like valve plug 30 which can be moved between a first position wherein the plug 30 intervenes inside a runner 18 to blockage the runner and a second position wherein it is evacuated from the inside to open the runner, and a driving means 34 which can move the rod like valve plug 30 in a freely sliding manner between the first position and the second position, are provided. Further, the rod like valve plug 30 is shifted to the second position wherein it is evacuated from the runner in pressure injection of the foaming material with the head. Further, when the pressure injection of the foaming material is ended, it is shifted to the first position wherein it blockades the runner, and prevents the foaming material after injection into the metal mold from flowing backwards. |
