US4231730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moulding video discs
Assignee: EMI Ltd
•
Filing: 1979-11-06
•
Granted: 1980-11-04
•
Expires: 1999-11-06
Abstract
Abstract A means for moulding thermoplastics video discs having one or two shaped resilient compensators to maintain the stamper plates in parallelism with the plastics foil during moulding. The compensators may be of a rubber and may contain a thermally conductive material.
Inventors
- 👤 David E. Birt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:32
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/02; B29D; B29D17/00; B29D17/005; B30; B30B; B30B15/00; B30B15/06; B30B15/061; Y; Y10; Y10S; Y10S425/00; Y10S425/81
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
119 words
An arrangement for impressing a surface of a thermoplastics foil with a relief structure, the arrangement comprising a pair of substantially parallel mould blocks, means for applying pressure to said mould blocks, a pair of substantially parallel stamper plates mounted between the mould blocks, at least one stamper plate bearing a negative impression of said relief structure, and interposed between an adjacent mould block and stamper plate a resilient material compensator, as hereinbefore defined, wherein at least one compensator has a convex surface, the ratio of the diameter of said surface to the depth thereof being no less that 340 and no greater than 3400, which arrangement is capable of impressing a thermoplastics foil positioned between the stamper plates.
Claim 2
Dependent Claim
119 words
An arrangement for impressing a surface of a thermoplastics foil with a relief structure, the arrangement comprising a pair of substantially parallel mould blocks, means for applying pressure to said mould blocks, a pair of substantially parallel stamper plates mounted between the mould blocks, at least one stamper plate bearing a negative impression of said relief structure, and interposed between an adjacent mould block and stamper plate a resilient material compensator, as hereinbefore defined, wherein at least one compensator has a convex surface, the ratio of the diameter of said surface to the depth thereof being no less that 340 and no greater than 3400, which arrangement is capable of impressing a thermoplastics foil positioned between the stamper plates.
Claim 3
Dependent Claim
17 words
An arrangement according to claim 1 wherein the said relief structure is indicative of information or data.
Claim 4
Dependent Claim
18 words
An arrangement according claim 1 or claim 2 wherein there are two compensators each having a convex surface.
Claim 5
Dependent Claim
17 words
An arrangement according to claims 1 or 2 wherein said convex surface is substantially spherical or conical.
Claim 6
Dependent Claim
29 words
An arrangement according to claim 1 or claim 2 wherein the at least one compensator is formed of rubber having an IRHD hardness in the range 60° to 75°.
Claim 7
Dependent Claim
15 words
An arrangement according to claim 5 wherein said IRHD hardness lies between 73° and 75°.
Claim 8
Dependent Claim
18 words
An arrangement according to claims 1 or 2 wherein said compensator is loaded with a thermally conductive material.
Claim 9
Dependent Claim
22 words
An arrangement according to claim 7 wherein the compensator is loaded with 60% to 75% by weight of said thermally conductive material.
Claim 10
Dependent Claim
18 words
An arrangement according to claims 7 wherein said thermally conductive material is carbon black or a metallic powder.
Claim 11
Dependent Claim
23 words
An arrangement according to claim 1 or claim 2 wherein the depth of said convex surface lies between 1 mm and 0.1 mm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |