| 摘要 |
PURPOSE:To enable gas to be injected into a molten resin within a cavity without enlarging the mold in size by constituting such that a slidable valve in the gas passage acts to open the gas supply conduit when gas pressure rises, and it also acts to close the gas supply conduit when gas is supplied into the cavity and thus the gas pressure lowers. CONSTITUTION:Molten resin is injected from an injection cylinder to a cavity 10 and filled appropriately in the cavity 10. After the injection of the molten resin is completed, gas is allowed to be fed from gas supply means through a gas supply conduit 4. The gas flows through a gas passage 6 and a cylinder part 5, as a result, a valve body 2 is forwarded by virtue of a gas pressure in opposition of the urging force of a spring 3. When the gas port 7 comes to the gas passage 6, the gas serves to break the solidified layer of resin formed on the gas injection port 1, and in consequence injected into the central part of the molten resin within the cavity 10. After the completion of gas, the gas pressure within the cylinder part 5 weakens, so that the valve body 2 retreats by the agency of the spring 3 and, therefore, the gas port 7 moves out of the gas passage 6, resulting in the interruption of gas. |
