Moulding apparatus

Claim 2

A moulding apparatus for moulding a hollow rubber article which is first formed in two or more separate parts, the apparatus comprising: a. means to pre-work unvulcanized rubber without any substantial curing, prior to the rubber being formed into the parts; b. two mould halves arranged for relative movement towards and away from each other, and each having a mould cavity for a respective one of said article parts, and a locking spue groove adjacent said mould cavity to prevent accidental displacement of a moulded article part from its respective mould cavity; c. two sleeves respectively surrounding and carried by said two mould halves and having similar radial cross-section; d. male formers to co-operate respectively with the mould cavities to provide mould chambers into which molten rubber can be fed to provide said article parts; e. means to feed the pre-worked rubber to said mould chambers; and f. means to provide super-atmospheric gaseous pressure in the space between the mould halves when separated apart, said last recited means including a retractable casing which is movable between an operative position in which the mould halves are enclosed in a gas-tight volume by the casing, and a retracted position in which the mould halves are not enclosed in a gas-tight volume, said casing having in two opposed walls thereof corresponding apertures which can engage in a gas-tight fit the two respective sleeves carried by the two mould halves.

Claim 3

A moulding apparatus according to claim 1 in which the mould halves are movable towards each other by means of a press.

Claim 4

A moulding apparatus according to claim 2 in which the casing is movable in the same direction as the line of action of the press.

Claim 5

A moulding apparatus according to claim 1 in which the casing is provided with seals which provide a gas-tight fit against the sleeves when the casing is in the operative position.

Claim 6

A moulding apparatus according to claim 4 in which the size of the sleeves and arrangement of the seals is such that the casing will maintain an internal gas pressure in both operative and retracted positions and during movement between them.

Claim 7

A moulding apparatus according to claim 1 in which the mould halves are movable towards and away from each other within the casing to permit the mould to be opened and closed while the casing is pressurized.

Claim 8

A moulding apparatus according to claim 1 in which the means to form moulded article parts of rubber in the mould cavities comprises a mould center-section including a pair of male formers for co-operation with the mould cavities, transfer chambers which can be filled with rubber compound and passages to permit rubber to be forced from said transfer chambers simultaneously to the mould chambers defined by the co-operation of the mould cavities and the co-operation of the mould cavities and the respective male formers to form moulded article parts.

Claim 9

A moulding apparatus according to claim 7 in which the mould center section is movable between two positions, one in alignment between the mould cavities the other clear of said mould cavities.

Claim 10

A moulding apparatus according to claim 8 further comprising a pair of heat sinks for the mould center section located in the position clear of the mould cavities to permit temperature control of the center section, and associated with one of said heat sinks an injection port from a filling screw for supply of rubber to the mould center section.

Claim 11

A moulding apparatus according to claim 9 further comprising a subsidiary press ram to close the heat sinks about the mould center section and hold the mould center section against the injection port to permit the transfer chambers in the mould center section to be filled with rubber from said injection port.

Claim 12

A moulding apparatus according to claim 8 in which the casing includes a carriage to support the mould center section when the casing is in the operative position, the casing having runners along which the carriage may be moved to carry the mould center-section between its two positions.

Claim 13

A moulding apparatus according to claim 7 in which the mould cavities are movable towards each other within the casing by two separate means, one a high pressure short stroking ram to force the cavities against the mould center-section to transfer rubber out of the transfer chambers and the other, at least one long stroking auxiliary ram to bring the mould cavities together to join the article parts after removal of the mould center section to a position clear of the mould cavities.

Claim 14

A moulding apparatus for moulding a hollow rubber article which is first formed in two separate parts, the apparatus comprising: upper and lower mould halves arranged in vertical alignment for relative movement towards and away from each other, each mould half having a mould cavity and a locking spue groove to prevent accidental displacement of a rubber part when moulded in that mould cavity; two sleeves each surrounding and carried by a respective mould half; a heat sink arranged in side-by-side relation with said upper and lower mould halves and comprising upper and lower heat sink members each having one or more cavities arranged in vertical alignment, said heat sink members being arranged for relative movement towards and away from each other; two sleeves each surrounding and carried by a respective heat sink member; a mould center section having two sets of male formers, one set corresponding to the cavities in both the upper mould half and to the cavities in the upper heat sink members, and the other set corresponding to the cavities in both the lower mould half and to the cavities in the lower heat sink members; and means to carry the center section from a first position in which the first and second sets of male formers are in alignment respectively with the cavities in the upper and lower mould halves, and a second position in which the male formers are in alignment respectively with the cavities in the upper and lower heat sink members, said center section having a chamber to receive molten uncured rubber, and conduits by which the rubber can be fed under pressure to said mould cavities, and a retractable casing mounted for movement between an operative position in which it encompasses the mould and an inoperative position in which the interior of the mould is accessible to the operator of the mould, said casing having in its upper and lower walls thereof apertures each provided with a seal which engages with a respective one of said sleeves carried by the mould halves and the heat sink members at least when the casing is in its operative position.

Claim 15

A moulding apparatus for moulding a hollow rubber article which is first formed in two separate parts, the apparatus comprising: upper and lower mould halves arranged in vertical alignment for relative movement towards and away from each other, each mould half having a mould cavity and a locking spue groove to prevent accidental displacement of a rubber part when moulded in that mould cavity; two sleeves each surrounding and carried by a respective mould half; a heat sink arranged in side-by-side relation with said upper and lower mould halves and comprising upper and lower heat sink members each having one or more cavities arranged in vertical alignment, said heat sink members being arranged for relative movement towards and away from each other; two sleeves each surrounding and carried by a respective heat sink member; a mould center section having two sets of male formers, one set corresponding to the cavities in both the upper mould half and to the cavities in the upper heat sink members, and the other set corresponding to the cavities in both the lower mould half and to the cavities in the lower heat sink members; and means to carry the center section from a first position in which the first and second sets of male formers are in alignment respectively with the cavities in the upper and lower mould halves, and a second position in which the male formers are in alignment respectively with the cavities in the upper and lower heat sink members, said center section having a chamber to receive molten uncured rubber, and conduits by which the rubber can be fed under pressure to said mould cavities, and a retractable casing mounted for movement between an operative position in which it encompasses the mould and an inoperative position in which the interior of the mould is accessible to the operator of the mould, said casing having in its upper and lower walls thereof apertures each provided with a seal which engages with a respective one of said sleeves carried by the mould halves and the heat sink members at least when the casing is in its operative position.