Patent US4644432A successfully refreshed from Google Patents.
US4644432A
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Three pole single element magnetic read/write head
Assignee: International Business Machines Corp
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Filing: 1985-01-28
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Granted: 1987-02-17
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Expires: 2005-01-28
Abstract
Abstract A magnetic head has three pole pieces that form a magnetic circuit. The magnetic pole pieces are arranged in a common plane so that the two outside pole pieces are each spaced from the central pole piece to form a transducing gap between each of the outside pole pieces and the central pole piece. A first and a second coil, each having the same magnetic sense, is wound on the magnetic structure between an outside and the center pole piece. The coils are connected in series for a write operation so that the flux in the outside pole pieces is additive for writing, and the coils are connected in series opposition for a read operation so that the flux produced in the center pole by a previously recorded magnetic transition in the magnetic recording medium adjacent to the transducing gaps is sensed additively in the coils.
Inventors
- 👤 David E. Heim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:31
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/02; G11B15/12; G11B5/00; G11B5/02; G11B5/09; G11B5/127; G11B5/17; G11B5/265; G11B5/2652; G11B5/2654; G11B5/2655; G11B5/2657; G11B5/31
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
153 words
A magnetic head structure for recording and reading magnetic transitions on a selectable one of a plurality of tracks on a magnetic recording medium comprising: a magnetic structure having three spaced pole pieces, said pole pieces comprising outside pole pieces each spaced from a central pole piece to form a transducing gap between each of said outside pole pieces and said central pole piece; first and second coils each wound on said magnetic structure between an outside and the center pole of said pole pieces; first control circuit means for connecting said coils in a first configuration for a write operation whereby the flux in said magnetic pole pieces is additive for writing; and second control circuit means for connecting said coils in a second configuration for a read operation so that a previously recorded magnetic transition in the magnetic recording medium adjacent to said transducing gaps is sensed additively in said coils.
Claim 2
Dependent Claim
153 words
A magnetic head structure for recording and reading magnetic transitions on a selectable one of a plurality of tracks on a magnetic recording medium comprising: a magnetic structure having three spaced pole pieces, said pole pieces comprising outside pole pieces each spaced from a central pole piece to form a transducing gap between each of said outside pole pieces and said central pole piece; first and second coils each wound on said magnetic structure between an outside and the center pole of said pole pieces; first control circuit means for connecting said coils in a first configuration for a write operation whereby the flux in said magnetic pole pieces is additive for writing; and second control circuit means for connecting said coils in a second configuration for a read operation so that a previously recorded magnetic transition in the magnetic recording medium adjacent to said transducing gaps is sensed additively in said coils.
Claim 3
Dependent Claim
43 words
The magnetic head structure as in claim 1 wherein said first and second coils each have the same sense, wherein said coils are connected in series for a write operation, and wherein said coils are connected in series opposition for a read operation.
Claim 4
Dependent Claim
29 words
The magnetic head structure as in claim 1 wherein each of said pole pieces terminates in pole tips, said pole tips being spaced apart to define said transducing gaps.
Claim 5
Dependent Claim
14 words
The magnetic head structure as in claim 3 wherein said pole tips are coplanar.
Claim 6
Dependent Claim
23 words
The magnetic head structure as in claim 4 wherein the gap lengths between adjacent pole tips in said common plane are substantially equal.
Claim 7
Dependent Claim
38 words
The magnetic head structure as in claim 3 wherein the thickness of said pole tips of said outer pole pieces is relatively thick and the thickness of said pole tip of said central pole piece is relatively thin.
Claim 8
Dependent Claim
35 words
The magnetic head structure as in claim 1 additionally comprising circuit means for sensing the voltage induced in said coils when said coils are connected in series opposition whereby a bipolar read signal is sensed.
Claim 9
Dependent Claim
47 words
The magnetic head structure as in claim 1 wherein said magnetic structure comprises three spaced pole pieces each having two ends and having a common back gap closure at one end where they make physical contact and being separated by a transducing gap at the other end.
Claim 10
Dependent Claim
25 words
The magnetic head structure as in claim 1 wherein said first and second control circuit means comprise a first and second selectively operable switching means.
Claim 11
Dependent Claim
38 words
The magnetic head structure as in claim 1 wherein, during a write operation, said flux in said outside pole pieces causes said outside pole pieces to be magnetized oppositely so that a horizontally recorded magnetic transition is written.
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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) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |