US4787002A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head having a read/write coil with a d.c. current through it for cancellation of leakage magnetic flux from erase coil
Assignee: Mitsubishi Electric Corp
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Filing: 1987-09-15
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Granted: 1988-11-22
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Expires: 2007-09-15
Abstract
Abstract A magnetic disk drive apparatus is disclosed including a read and write head having a read and write coil and an erase head having an erase coil at the opposite sides of the read and write head for erasing data at the both sides of the written data track, the improvement includes a leakage magnetic flux cancelling coil wound on the read and write head which is energized with a d.c. current for cancelling the leakage magnetic flux from the erase head when the erase coil is energized with a d.c. current.
Inventors
- 👤 Shin Isozaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:53
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/265; G11B5/2652; G11B5/2654; G11B5/2655; G11B5/012; G11B5/17; G11B5/02; G11B5/024
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
249 words
A magnetic head for use in a magnetic disc drive apparatus for performing read/write operations, said magnetic head comprising: a read/write head having a read/write coil with a center tap to divide said read/write coil into a first section and a second section; an amplifying circuit means for supplying a write current through said read/write coil in accordance with data to be written during a write mode, said write current including a first write current flowing through said first section and a second write current flowing through said second section, said first write current flowing alternately with said second write current and in an opposite direction; an erase head having an erase coil through which an erase current flows during said write mode for erasing on both sides of a data track written by said read/write head, said erase head causing a magnetic leakage flux in an opposite direction to a magnetic flux set up by said first write current; an erase switch circuit means provided in series with a DC voltage source and said erase coil, said erase switch circuit means being closed during said write mode for supplying said erase current and for causing a DC current therefrom to flow through said first section in the same direction as said first write current, such that said DC current generates a magnetic flux in an opposite direction to said magnetic leakage flux caused by said erase head in said read/write head, thereby cancelling out said magnetic leakage flux.
Claim 2
Dependent Claim
249 words
A magnetic head for use in a magnetic disc drive apparatus for performing read/write operations, said magnetic head comprising: a read/write head having a read/write coil with a center tap to divide said read/write coil into a first section and a second section; an amplifying circuit means for supplying a write current through said read/write coil in accordance with data to be written during a write mode, said write current including a first write current flowing through said first section and a second write current flowing through said second section, said first write current flowing alternately with said second write current and in an opposite direction; an erase head having an erase coil through which an erase current flows during said write mode for erasing on both sides of a data track written by said read/write head, said erase head causing a magnetic leakage flux in an opposite direction to a magnetic flux set up by said first write current; an erase switch circuit means provided in series with a DC voltage source and said erase coil, said erase switch circuit means being closed during said write mode for supplying said erase current and for causing a DC current therefrom to flow through said first section in the same direction as said first write current, such that said DC current generates a magnetic flux in an opposite direction to said magnetic leakage flux caused by said erase head in said read/write head, thereby cancelling out said magnetic leakage flux.
Claim 3
Dependent Claim
41 words
The magnetic head of claim 1, wherein said first section is provided with an auxiliary tap therein, and said erase current flowing out of said erase coil is supplied to said first section via said auxiliary tap as said DC current.
References Cited (Backward Citations)
JPS5687215A
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JPS5798124A
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JPS5864609A
Cited
JPS58125220A
Cited
JPS59139120A
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JPS59229703A
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US4680657A
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EP0175800A1
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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) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |