Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
292 words
A molding apparatus for producing record discs, comprising: first and second mold halves reciprocally movable with respect to each other between a closed position, wherein the parting line between the two mold halves is closed and an annular cavity is formed therebetween, and wherein a molten material can be injected into the annular cavity to form a record disc, and an open position, wherein the parting line is open and the molded record disc can be removed; a planar, disc-shaped stamper secured to one of said first and second mold halves, said stamper defining one side of the annular cavity; and means for limiting the reciprocal movements of said first and second mold halves, to define said closed position, said means including a first annular ring fixedly secured to said first mold half, said first ring having an outwardly-facing abutment face, and a second annular ring fixedly secured to said second mold half, said second ring having an outwardly-facing abutment face 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, wherein the inner periphery of the annular ring for the mold half carrying said stamper is defined by an inwardly projecting annular foot that retains the outer periphery of the stamper, said annular foot being spaced from said mold half by a distance greater than the thickness of said stamper to permit the stamper to expand radially, without substantial frictional resistance, when heated by the molten material injected into the cavity, and wherein at least one of said first and second rings includes means for venting air from the cavity whenever molten material is being injected therein.
Claim 2
Dependent Claim
292 words
A molding apparatus for producing record discs, comprising: first and second mold halves reciprocally movable with respect to each other between a closed position, wherein the parting line between the two mold halves is closed and an annular cavity is formed therebetween, and wherein a molten material can be injected into the annular cavity to form a record disc, and an open position, wherein the parting line is open and the molded record disc can be removed; a planar, disc-shaped stamper secured to one of said first and second mold halves, said stamper defining one side of the annular cavity; and means for limiting the reciprocal movements of said first and second mold halves, to define said closed position, said means including a first annular ring fixedly secured to said first mold half, said first ring having an outwardly-facing abutment face, and a second annular ring fixedly secured to said second mold half, said second ring having an outwardly-facing abutment face 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, wherein the inner periphery of the annular ring for the mold half carrying said stamper is defined by an inwardly projecting annular foot that retains the outer periphery of the stamper, said annular foot being spaced from said mold half by a distance greater than the thickness of said stamper to permit the stamper to expand radially, without substantial frictional resistance, when heated by the molten material injected into the cavity, and wherein at least one of said first and second rings includes means for venting air from the cavity whenever molten material is being injected therein.
Claim 3
Dependent Claim
65 words
A molding apparatus as defined in claim 1, wherein: said means for venting air includes a plurality of circumferentially spaced, radially aligned grooves in the abutment face of the corresponding annular ring, communicating with the annular cavity; and the cross-sectional size of each of said plurality of radially aligned grooves increases a prescribed distance from the inner peripheries of said first and second annular rings.
Claim 4
Dependent Claim
44 words
A molding apparatus as defined in claim 1, wherein the inwardly projecting annular foot includes a planar retaining face parallel to the plane of the stamper and to the plane of the abutment faces, for slidably securing the stamper to the corresponding mold half.
Claim 5
Dependent Claim
35 words
A molding apparatus as defined in claim 1, wherein the inner periphery of the inwardly projecting annular foot is beveled, to grip the molded record disc when the apparatus is moved to the open position.
Claim 6
Dependent Claim
43 words
A molding apparatus as defined in claim 1, wherein the radial length of said annular foot is greater than the radial expansion of the stamper as it is heated for room temperature to the temperature of the molten material injected into the cavity.