Patent US4458858A successfully refreshed from Google Patents.
US4458858A
Expired / Lapsed
US
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Bowed cassette shim and method for making
Assignee: 3M Co
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Filing: 1982-01-07
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Granted: 1984-07-10
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Expires: 2002-01-07
Abstract
Abstract A method is described for forming a novel bowed shim for a cassette which includes impacting one surface of a sheet of polymeric material with particles until layer-like portions adjacent its surfaces are differentially expanded and the material is bowed, and then cutting the shim from the material.
Inventors
- 👤 Norman E. Nelson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:50
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/02; G11B23/04; G11B23/08; G11B23/087; G11B23/08707; G11B23/08757; G11B23/08764; Y; Y10; Y10S; Y10S242/00; Y10S242/90
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
159 words
In a cassette of the type including a case, two spools rotatably mounted in aligned, axially parallel, spaced relationship within the case, a length of tape having opposite end portions helically wound in coils about the spools and having a portion extending therebetween, means on the case defining a path for the portion of tape extending between the coils, and a pair of shims of resilient elastic polymeric material on the opposite sides of said spools between said spools and said case, the improvement wherein said shims each comprise a first layer-like portion adjacent said spools and a second layer-like portion adjacent said case with said first layer-like portion applying a stress in all directions along said second layer-like portion to form in the free, unassembled state of said shim a spherically convex outer surface on said first layer-like portion, said shims being resiliently deflected between said case and said spools to bias said spools to central positions therebetween.
Claim 2
Dependent Claim
159 words
In a cassette of the type including a case, two spools rotatably mounted in aligned, axially parallel, spaced relationship within the case, a length of tape having opposite end portions helically wound in coils about the spools and having a portion extending therebetween, means on the case defining a path for the portion of tape extending between the coils, and a pair of shims of resilient elastic polymeric material on the opposite sides of said spools between said spools and said case, the improvement wherein said shims each comprise a first layer-like portion adjacent said spools and a second layer-like portion adjacent said case with said first layer-like portion applying a stress in all directions along said second layer-like portion to form in the free, unassembled state of said shim a spherically convex outer surface on said first layer-like portion, said shims being resiliently deflected between said case and said spools to bias said spools to central positions therebetween.
Claim 3
Dependent Claim
19 words
A cassette according to claim 1 wherein said polymeric material is carbon filled ultra high molecular weight density polyethylene.
Claim 4
Dependent Claim
14 words
A cassette according to claim 1 wherein said polymeric material is graphite coated polyester.
Claim 5
Dependent Claim
101 words
A shim adapted to be inserted between a case and side surfaces of spools in a cassette, wherein said shim is of a resiliently elastic polymeric material and comprises a first layer-like portion defining a first surface of said shim adapted to contact the side surfaces of the spools, and a second layer-like portion on the side of said first layer-like portion opposite said first surface, said first layer-like portion applying a stress in all directions along said second layer-like portion to bow said shim in its free state, prior to insertion and cause said first surface to be spherically convex.
Claim 6
Dependent Claim
101 words
A shim adapted to be inserted between a case and side surfaces of spools in a cassette, wherein said shim is of a resiliently elastic polymeric material and comprises a first layer-like portion defining a first surface of said shim adapted to contact the side surfaces of the spools, and a second layer-like portion on the side of said first layer-like portion opposite said first surface, said first layer-like portion applying a stress in all directions along said second layer-like portion to bow said shim in its free state, prior to insertion and cause said first surface to be spherically convex.
Claim 7
Dependent Claim
20 words
A shim according to claim 4 wherein said polymeric material is carbon filled ultra high molecular weight high density polyethylene.
Claim 8
Dependent Claim
14 words
A shim according to claim 4 wherein said polymeric material is graphite coated polyester.
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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) | 1987-07-10 | 1988-01-09 | 1988-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-10 | 1992-01-09 | 1992-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-10 | 1996-01-09 | 1996-07-10 | $7700.00 | Window Closed / Lapsed |