GB1469110A - Moudling apparatus - Google Patents

Abstract

1469110 Moulding rubber articles DUNLOP Ltd 2 Aug 1974 [14 Aug 1973] 38338/73 Heading B5A Article parts of uncured rubber, e.g. annular halves of a tyre inner tube, are formed in the opposed cavities of mould halves 3, 7 in association with a core assembly 27-29, which halves are then brought together, after removing the core, to join and cure the parts. Grooves 14a, 14b, 15a, 15b in the mould halves receive uncured rubber during the injection of the rubber into the cavities and prevent the displacement of the parts on mould opening and core removal. The mould is pressurized with gas during the moulding by a casing 9 vertically movable to a position to enclose the cavities and to a retracted position wherein the cavities are accessible. The mould halves are located in a press 1, 2 provided with opposed heat sinks 4, 8; the lower mould half and heat sink are vertically movable by rams. The casing has seals 21-24 which slidably engage cylindrical sleeves 10-13 surrounding the mould halves and heat sinks when the casing is raised to its operative position by a ram. In operation, the core is located between the heat sinks, with its parts 28, 29, spaced from the part 27, Fig. 5, where a transfer chamber 32 receives a measured supply of rubber from an injection screw 5. During this time the formers 30, 31 of the core are cooled by the heat sinks. The latter are then separated and the core lowered and fed to between the mould halves; such feeding is effected by a carriage supported by the casing which is raised. The mould halves are then urged together, Fig. 6, forcing the uncured rubber from the transfer chamber through passages 35, 36 into the mould cavities and grooves. During this period the casing is pressurized. The mould halves are heated by steam circulation through passages 39, 40 when the core is removed and the mould halves brought together to join and cure the moulded parts.