| 摘要 |
PURPOSE:To contrive extension of life by making highly accurate part unnecessary, by so constituting the title valve that either a pressure difference between resin at a front flow path and that at a rear flow path becomes small or a gate is closed when the resin pressure becomes lower than a predetermined value. CONSTITUTION:A gate is formed of a ring 12 dividing a flow path 11 communicating a resin lead-in port 9 and resin spouting port 10 with each other into two. The flow path 11 is divided into a front flow path 11a and rear flow path 11b by the ring 12 and the ring 12 is abutted against a stepped part 8a provided in the flow path 11. A groove 14 is provided on a sprue 13 in an axial direction of the outer circumference of the same provided slidably on the inner circumference of the ring 12 and a protrusion 15 is provided on the rear of the sprue 13. As for a spring 16, one side of the same is abutted against the protrusion 15, the other side is abutted against the stepped part 8a through the ring 12 and sprue 13 is energized backward. With this construction, when eiter a pressure difference between resin at the front flow path and that at the rear flow path becomes small or resin pressure becomes lower than a predetermined value by filling the inside of a mold with the resin, the flow path 11 is closed by sliding the sprue 13 backward through the spring 16.
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