Moulding apparatus for record discs

Claim 2

A moulding apparatus for producing record discs, comprising: first and second mould halves (11, 17) reciprocally movable with respect to each other between a closed position,wherein the parting line between the two mould halves is closed and an annular cavity (31) is formed therebetween, and wherein a molten material can be injected into the annular cavity to form a record disc (10), and an open position, wherein the parting line is open and the moulded record disc can be removed; and means for limiting the reciprocal movement of said first and second mould halves, to define said closed position, said means including a first annular ring (41) fixedly secured to said first mould half, said first ring having an outwardly-facing abutment face-(47), and a second annular ring (43) fixedly secured to said second mould half, said second ring having an outwardly-facing abutment face (49) for abutment with the abutment face of said first ring when the apparatus is in said closed position, the inner peripheries of said first and second rings defining the perimeter of said annular cavity, said first and second rings including means defining a plurality of vent ports (45) arranged in spaced relationship around their inner peripheries, to vent air from the annular cavity whenever molten material is being injected therein.

Claim 3

A moulding apparatus as defined in Claim 1, wherein: said apparatus further includes a planar, disc-shaped stamper (33 or 35) secured to one of said first and second mould halves, said stamper defining one side of the annular cavity; and the inner periphery of the corresponding one of said first and second annular rings is defined by an inwardly projecting annular foot (53) to retain the outer periphery of said stamper.

Claim 4

A moulding apparatus as defined in Claim 2, wherein s'aid inwardly projecting annular foot is sized to permit said stamper to expand radially, without substantial frictional resistance, when heated by the molten material injected into the cavity.

Claim 5

A moulding apparatus as defined in any preceding Claim, wherein the inner periphery of at least one of said first and second annular rings is beveled, whereby the moulded record disc is gripped by the ring when the apparatus is moved to the open position.

Claim 6

A moulding apparatus as defined in any preceding claim, wherein the vent-ports are defined by radial grooves in the abutment face of at least one of said first and second annular rings.

Claim 7

A moulding apparatus as defined in Claim 5, wherein the cross-sectional size of each groove increases a certain distance from the inner peripheries of the annular rings.

Claim 8

A moulding apparatus for producing record discs, said apparatus including first and second mould halves (11, 17) defining an annular cavity (31) therebetween into which molten material is injected to form a record disc (10), each of said mould halves including a platen (55, 57) having means (59) for dissipating heat from the molten material injected into the cavity, said apparatus further including a disc-shaped stamper (33) coupled to said first mould half platen and defining one side of the annular cavity, the stamper being coupled to said first mould half platen (55) by a plate (63) removably secured to said platen, said stamper being, in turn, removably mounted on the plate, whereby the stamper can be mounted at a remote, clean location, after which the plate, with the stamper mounted thereon, can be secured to the platen, thereby reducing substantially the possibility of inadvertently damaging the stamper while mounting it in the apparatus.

Claim 9

A moulding apparatus for producing record discs, said apparatus including first and second mould halves (11, 17) defining an annular cavity (31) therebetween into which molten material is injected to form a record disc (10), each of said mould halves including a platen (55, 57) having means (59) for dissipating heat from the molten material injected into the cavity, said apparatus further including a disc-shaped stamper (33) coupled to said first mould half platen and defining one side of the annular cavity, the stamper being coupled to said first mould half platen (55) by a plate (63) removably secured to said platen, said stamper being, in turn, removably mounted on the plate, whereby the stamper can be mounted at a remote, clean location, after which the plate, with the stamper mounted thereon, can be secured to the platen, thereby reducing substantially the possibility of inadvertently damaging the stamper while mounting it in the apparatus.

Claim 10

An apparatus as defined in Claim 7 including a second plate (65) removably secured to said second mould half platen (57), one surface of said second plate being polished and defining a second side of the annular cavity.

Claim 11

A moulding apparatus having first and second mould halves (11,17) reciprocally movable with respect to each other between a closed position, wherein the two mould halves are in abutment, and an open position, wherein the two mould halves are spaced apart, and -including alignment means (123,125) carried by said first and second mould halves for maintaining the two mould halves properly aligned with respect to each other when the apapratus is in the closed position, said alignment means not being subject to sliding friction when the mould halves are moved reciprocally between the closed and open positions.

Claim 12

A moulding apparatus having first and second mould halves (11,17) reciprocally movable with respect to each other between a closed position, wherein the two mould halves are in abutment, and an open position, wherein the two mould halves are spaced apart, and -including alignment means (123,125) carried by said first and second mould halves for maintaining the two mould halves properly aligned with respect to each other when the apapratus is in the closed position, said alignment means not being subject to sliding friction when the mould halves are moved reciprocally between the closed and open positions.

Claim 13

An apparatus as defined in Claim 9, wherein said alignment means includes frusto-conical posts(123) projecting outwardly from said first mould half, and- frusto-conical recesses (125) formed in the other mould half to conformably receive said posts.

Claim 14

An apparatus as defined in Claim 9 or Claim 10 further including means for maintaining a coarse alignment between said first and second mould halves, said means including guide pins (25) secured to one mould half and bushings (29) secured to the other mould half for slidably receiving said guide pins.

Claim 15

A moulding apparatus for producing a centrally-apertured record disc (10), said apparatus including a first mould half (11) having a base plate (13) and a carrier plate (15) reciprocally movable with respect to each other, a second mould half (17) reciprocally movable relative to the first mould half, and a punch (89) the moulding apparatus being in a machine coupled to the base plate of the first mould half and to the second mould half and operating to move the apparatus successively from a closed position, wherein the parting line between the first and second mould halves is closed and the record disc is moulded and wherein the base plate and the carrier plate of the first mould half are in abutment with each other, to a punch position, wherein the parting line remains closed to hold the moulded disc securely in place and wherein the base plate and the carrier plate of the first mould half are spaced apart from each other and the punch is actuated to produce a central aperture in the moulded disc, and, in turn, to an open position, wherein the parting line is open and the centrally-apertured disc can be removed;and comprising at least one compression spring (105) coupled between the base plate and the carrier plate of said first mould half, to urge the carrier plate into compressive engagement with the second mould half and thereby hold the parting line closed when the apparatus is in the punch position.

Claim 16

A moulding apparatus for producing a centrally-apertured record disc (10), said apparatus including a first mould half (11) having a base plate (13) and a carrier plate (15) reciprocally movable with respect to each other, a second mould half (17) reciprocally movable relative to the first mould half, and a punch (89) the moulding apparatus being in a machine coupled to the base plate of the first mould half and to the second mould half and operating to move the apparatus successively from a closed position, wherein the parting line between the first and second mould halves is closed and the record disc is moulded and wherein the base plate and the carrier plate of the first mould half are in abutment with each other, to a punch position, wherein the parting line remains closed to hold the moulded disc securely in place and wherein the base plate and the carrier plate of the first mould half are spaced apart from each other and the punch is actuated to produce a central aperture in the moulded disc, and, in turn, to an open position, wherein the parting line is open and the centrally-apertured disc can be removed;and comprising at least one compression spring (105) coupled between the base plate and the carrier plate of said first mould half, to urge the carrier plate into compressive engagement with the second mould half and thereby hold the parting line closed when the apparatus is in the punch position.

Claim 17

An apparatus as defined in Claim 12, wherein said compression spring comprises at least one solid block (105) of a resilient material in a recess (107) formed in the base plate or the carrier plate of said first mould half.