| 摘要 |
PURPOSE:To change over a fluid by a simple construction by a method wherein a first path and a second path are respectively provided upstream and downstream of a piston part on a side face of a mandrel, the first path is closed by a first valve with the upstream travel of the mandrel, and the second path is closed by a second valve with the downstream travel of the mandrel. CONSTITUTION:Upstream of a piston part 23, a first path 2b is provided so as to pass through a mandrel 20 and connect to a port 12 and an injection port 11, and a first valve part 17 is provided. Downstream of the piston part 23, a second path 28 is provided so as to connect to a supply port 13 and the injection port 11, and a second valve part 18 is provided. The mandrel 20 moves downward by the pressure of a melt resin. The first valve part 17 is opened. The second valve part 18 is closed. The first path 26 is connected. Thus, the melt resin is injected from the injection port 11. On the other hand, the second path 28 is interrupted. Next, the mandrel 20 moves upstream by feeding a high- pressure nitrogen gas into a die 10. On the contrary, the second path 28 is connected, and the first path 26 is interrupted. |
