Patent US5087998A successfully refreshed from Google Patents.
US5087998A
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US
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Magnetic tape cassette having improved erasure preventing device
Assignee: Rolls Royce PLC
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Filing: 1988-12-29
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Granted: 1992-02-11
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Expires: 2008-12-29
Abstract
Abstract A magnetic tape cassette of the β cam or β cam SP type having an improved mistake erasing preventing construction and improved dustproofing property. For the β cam SP type cassette, a movable plug is provided in an insertion hole formed in the bottom face of the cassette housing and a snap-off tab is removed beforehand, while for the β cam type cassette, an immovable plug is provided in the insertion hole and the snap-off tab is left intact.
Inventors
- 👤 Kengo Oishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:48
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/02; G11B23/04; G11B23/08; G11B23/087; G11B23/08707; G11B23/08714
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
119 words
A magnetic tape cassette, comprising: a cassette casing in which a pair of tape reels on which a magnetic tape is wound are rotatably housed, an insertion hole being formed on an end face of said cassette casing, said hole being disposed near one end of an openable lid of said casing; a snap-off tab positioned in said end face near an opposite end of said openable lid, said tab in-turn covers a cavity which can accept an erasure prevention detecting member therein; and an immovable plug for inserting into and which becomes immovable when fitted in said insertion hole for covering said insertion hole, wherein said insertion hole can accommodate said immovable plug or movable erasure prevention plug.
Claim 2
Dependent Claim
119 words
A magnetic tape cassette, comprising: a cassette casing in which a pair of tape reels on which a magnetic tape is wound are rotatably housed, an insertion hole being formed on an end face of said cassette casing, said hole being disposed near one end of an openable lid of said casing; a snap-off tab positioned in said end face near an opposite end of said openable lid, said tab in-turn covers a cavity which can accept an erasure prevention detecting member therein; and an immovable plug for inserting into and which becomes immovable when fitted in said insertion hole for covering said insertion hole, wherein said insertion hole can accommodate said immovable plug or movable erasure prevention plug.
Claim 3
Dependent Claim
20 words
The magnetic tape cassette of claim 1, wherein said immovable plug is secured in said insertion hole by an adhesive.
Claim 4
Dependent Claim
43 words
The magnetic tape cassette of claim 1, wherein said cassette casing has a notch formed in a side of said insertion hole, and wherein said immovable plug has an engaging convex portion which fills said notch to prevent said immovable plug from moving.
Claim 5
Dependent Claim
30 words
The magnetic tape cassette of claim 2, wherein said immovable plug is secured in said insertion hole by an adhesive in areas between said engaging convex portion and said notch.
Claim 6
Dependent Claim
35 words
The magnetic tape cassette of claim 2, wherein said immovable plug further has first and second hook-like retainer portions engaging, respectively, a retainer aperture below said notch and a rear wall of said insertion hole.
References Cited (Backward Citations)
US4791504A
Cited
US4811150A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-02-10 | 1995-08-12 | 1996-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-10 | 1999-08-12 | 2000-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-10 | 2003-08-12 | 2004-02-11 | $7700.00 | Window Closed / Lapsed |