US3753093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and equipment for the determination of the degree of abrasiveness of magnetic tape
Assignee: Fulmer Research Institute Ltd
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Filing: 1971-12-29
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Granted: 1973-08-14
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Expires: 1991-12-29
Abstract
Abstract A method is described for the determination of the degree of abrasiveness of magnetic tape which method comprises passing the magnetic tape over the working surface of a simulated recording head fabricated of an electrically non-conducting material and geometrically closely approximating the dimensions of an actual recording head, the working surface of the simulated head having deposited thereon one or more thin strips of a magnetic alloy similar to the magnetic alloy used for the actual head, and observing the increase in electrical resistance of the magnetic alloy strip or strips. A device suitable for use in the method is also disclosed.
Inventors
- 👤 D Stewart
- 👤 G Williams
- 👤 L Gardner
- 👤 N Helbren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:40
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/40; G01; G01N; G01N3/00; G01N3/56; G11B5/74
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
120 words
A method for the determination of the degree of abrasiveness of magnetic tape, which method comprises passing the magnetic tape substantially at a normal operating speed over the working surface of a simulated recording head, fabricated of an electrically non-conducting material and geometrically closely approximating the dimensions of an actual recording head, the working surface of the simulated recording head possessing substantially the same dimensions and contours as the working surface of the actual head, said working surface of the simulated head having deposited thereon one or more thin strips of a magnetic alloy substantially similar to the magnetic alloy used in the actual recording head, and measuring the increase in electrical resistance of said magnetic alloy strip or strips.
Claim 2
Independent Claim
120 words
A method for the determination of the degree of abrasiveness of magnetic tape, which method comprises passing the magnetic tape substantially at a normal operating speed over the working surface of a simulated recording head, fabricated of an electrically non-conducting material and geometrically closely approximating the dimensions of an actual recording head, the working surface of the simulated recording head possessing substantially the same dimensions and contours as the working surface of the actual head, said working surface of the simulated head having deposited thereon one or more thin strips of a magnetic alloy substantially similar to the magnetic alloy used in the actual recording head, and measuring the increase in electrical resistance of said magnetic alloy strip or strips.
Claim 3
Dependent Claim
15 words
A method according to claim 1 wherein the simulated recording head is fabricated from alumina.
Claim 4
Dependent Claim
30 words
A method according to claim 1 wherein the surfaces of the simulated recording head are fine ground to the required dimensions with a surface finish of approximately 25 micro in.
Claim 5
Dependent Claim
27 words
A method according to claim 1 wherein the working surface of the simulated recording head is polished to a surface finish of better than 20 micro in.
Claim 6
Dependent Claim
32 words
A method according to claim 1 wherein the thin strips of magnetic alloy provided on the working surface of the simulated recording head have a thickness of from 700 to 1,000 A.
Claim 7
Dependent Claim
23 words
A method according to claim 1 wherein the thin strips deposited on the working surface of the simulated recording head are of nichrome.
Claim 8
Dependent Claim
49 words
A method accordinG to claim 1 wherein conducting films are deposited on the simulated recording head at each end of each strip of magnetic alloy so that electrical connections may be made between the strips of magnetic alloy and a resistance-measuring means for measuring said increase in electrical resistance.
Claim 9
Dependent Claim
116 words
A method according to claim 1 wherein: a. the simulated recording head is fabricated from alumina which is b. fine ground to the required dimensions with a surface finish of approximately 25 micro in. and the working surface thereof polished to a surface finish of better than 20 micro in.; c. the thin strips of magnetic alloy provided on the working surface of the simulated recording head are of nichrome and have a thickness of from 700 to 1,000 A; and d. conducting gold films are deposited on the simulated recording head at each end of each strip of nichrome in order that electrical connections may be made between the said nichrome strips and resistance-measuring circuits.
Claim 10
Independent Claim
90 words
A device for the determination of the degree of abrasiveness of magnetic tape, comprising a simulated recording head fabricated of an electrically non-conducting material and geometrically closely approximating the dimensions of an actual recording head, the working surface of the simulated recording head possessing substantially the same dimensions and contours as the working surface of the actual head, said working surface of the simulated head having deposited thereon one or more strips of a magnetic alloy substantially similar to the magnetic alloy which is used in said actual recording head.
Claim 11
Independent Claim
90 words
A device for the determination of the degree of abrasiveness of magnetic tape, comprising a simulated recording head fabricated of an electrically non-conducting material and geometrically closely approximating the dimensions of an actual recording head, the working surface of the simulated recording head possessing substantially the same dimensions and contours as the working surface of the actual head, said working surface of the simulated head having deposited thereon one or more strips of a magnetic alloy substantially similar to the magnetic alloy which is used in said actual recording head.
Claim 12
Dependent Claim
116 words
A device according to claim 9 wherein: a. the simulated recording head is fabricated from alumina which is b. fine ground to the required dimensions with a surface finish of approximately 25 micro in. and the working surface thereof polished to a surface finish of better than 20 micro in.; c. the thin strips of magnetic alloy provided on the working surface of the simulated recording head are of nichrome and have a thickness of from 700 to 1,000 A; and d. conducting gold films are deposited on the simulated recording head at each end of each strip of nichrome in order that electrical connections may be made between said nichrome strips and a resistance-measuring means.
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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) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |