| 摘要 |
972,861. Moulding cellular articles. SPRING- FIELD CAST PRODUCTS Inc. Oct. 17, 1961, No. 37147/61. Heading B5A. Thermal - insulating cellular articles are moulded from granules of polystyrene expanded by a blowing agent, methylchloride, butane or heptane by feeding the granules from a hopper 140 through a valve 146 down a hollow runner 62 through openings 64 into mould cavities 60, defined between two co-operating mould faces 40, 50 when they are in contact, heating the granules by allowing steam to pass through apertures 61 to the mould cavities 60 from steam chests 42, 52, cooling the articles by spraying water into and against the back of the mould cavities 60, opening the mouth parts and ejecting the articles by the forward movement of spring-loaded ejector pins 70, which are interconnected with a piece of wire 76 to prevent rotation of the pins 70. The mould cavities 60 may be presteamed before they are filled and the granules may be pre-foamed before they are used for moulding. The mould faces 40, 50 are attached to head platens 30, 20 and steam chests 42, 52 respectively, the head platen 20 being fixed so to form the mould cavities 60. The head platen 30 is advanced towards the other by the pressure of a power ram 120. To close the mould cavities 60 when they are filled, the position of the runner 62 is altered to move the openings 64 out of registry with their respective openings in the mould cavities 60, afterwards the excess material in the runner 62 is blown out and returned to the hopper 140. The mould faces 40 and 50, which are reinforced by ribs 77, are interchangeable so that different articles may be moulded using the same machine. The machine has incorporated time and pressure switches so that the steps of the process are performed automatically on a cyclical basis. |
