| 摘要 |
1291111 Injection moulding machines IMPERIAL CHEMICAL INDUSTRIES Ltd 26 Jan 1970 [18 Feb 1969] 8714/69 Heading B5A Material is injected into a mould from two separate sources 1, 2 via separate bores 3, 4 which converge into a single sprue 6, a shuttle valve 9 being adapted to slide across the paths 3, 4 of the materials so as to open and close the two bores and the position of the shuttle 9 is determined by the relative pressures exerted on the shuttle by the two materials. Thus the shuttle 9 has cut-away portions 10, 11 acted on by the material in the channels 4, 3 respectively. A rotary shut-off tap 5 is provided between the shuttle 9 and the sprue 6. As shown, the shuttle valve is provided in the end cap 8 of the injection machine but it may be in the walls of the mould itself. The invention may be applied to the making of laminar articles, e.g. having a foamed core. A first material is injected under a pressure higher than that on a second material, the latter pressure being increased while the first material is being injected so that it becomes greater than that on the first material when a sufficient quantity of the first material has been injected so that the shuttle slides to allow the second material to be injected. A second amount of the first material may be subsequently injected. Reference has been directed by the Comptroller to Specification 1,156,217.
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