US4149204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Minor bit reduction on a magnetic head
Assignee: International Business Machines Corp
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Filing: 1977-03-28
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Granted: 1979-04-10
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Expires: 1997-03-28
Abstract
Abstract A magnetic head assembly for cooperating with a relatively moving medium, on which servo information and data information is recorded, and for reading and/or writing on said medium and for erasing said medium is fabricated so that the effect of pickup interference or unwanted signals during playback is reduced. The magnetic head assembly incorporates a geometry which shifts the signal envelope of the interfering signal so that it is in phase with the signal envelope of the desired signal. The preferred geometry is to dimension the head core so that the distance between two gaps or between a single gap and the edge of the core is equal to the distance between the servo tracks on said medium. Additionally, the gap of the head has a gap null occurring at the frequency of the interfering signal.
Inventors
- 👤 Peter T. Marino
- 👤 Frank B. Shelledy
- 👤 Edmond W. Smathers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:52
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/265; G11B5/187; G11B5/48; G11B5/58; G11B5/584; G11B5/588
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
147 words
A magnetic head assembly, for use with a relatively moving magnetic medium having longitudinal servo tracks and data tracks inclined to said servo tracks, said magnetic head moving traversely across the servo track at a predetermined angle to the longitudinal axis of said servo tracks, comprising: a gap for reproducing signals prerecorded on said medium and for recording signals thereon; a first pole piece; a second pole piece cooperating with said first pole piece to form the gap with the outside edge of said second pole piece having a sharp configuration and being the leading edge of the head; said second pole piece having a lengthwise dimension substantially equivalent to the effective spacing between the servo tracks, at the angle of traverse, said measurement being along the direction of head motion; and coil means seated on one of said pole pieces, for reproducing and recording the signals.
Claim 2
Dependent Claim
147 words
A magnetic head assembly, for use with a relatively moving magnetic medium having longitudinal servo tracks and data tracks inclined to said servo tracks, said magnetic head moving traversely across the servo track at a predetermined angle to the longitudinal axis of said servo tracks, comprising: a gap for reproducing signals prerecorded on said medium and for recording signals thereon; a first pole piece; a second pole piece cooperating with said first pole piece to form the gap with the outside edge of said second pole piece having a sharp configuration and being the leading edge of the head; said second pole piece having a lengthwise dimension substantially equivalent to the effective spacing between the servo tracks, at the angle of traverse, said measurement being along the direction of head motion; and coil means seated on one of said pole pieces, for reproducing and recording the signals.
Claim 3
Dependent Claim
142 words
In a magnetic recorder wherein a recording surface is positioned relative to a recording transducer and said transducer is aligned with a selected data track by use of servo indicia in servo tracks located on said recording surface said transducer moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks the improvement comprising in combination: a recording means having spaced longitudinal servo tracks with servo indicia thereon and data tracks inclined to the servo tracks; a transducer means, associated with said recording means, having a gap for reading and recording data and having a sharp leading edge; said gap positioned so that the distance between the gap and the sharp leading edge of said transducer is substantially equal to the effective distance between the centerlines of the servo tracks, at the angle of traverse.
Claim 4
Dependent Claim
142 words
In a magnetic recorder wherein a recording surface is positioned relative to a recording transducer and said transducer is aligned with a selected data track by use of servo indicia in servo tracks located on said recording surface said transducer moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks the improvement comprising in combination: a recording means having spaced longitudinal servo tracks with servo indicia thereon and data tracks inclined to the servo tracks; a transducer means, associated with said recording means, having a gap for reading and recording data and having a sharp leading edge; said gap positioned so that the distance between the gap and the sharp leading edge of said transducer is substantially equal to the effective distance between the centerlines of the servo tracks, at the angle of traverse.
Claim 5
Dependent Claim
129 words
Apparatus for reducing defects in the reproduced servo envelopes of a recorder comprising: a length of magnetic media having servo tracks thereon for track following and inclined data tracks; said servo tracks are parallel to an elongated edge of said length of magnetic media; a magnetic head, having a core geometry with a sharp leading edge a trailing edge and a gap therebetween, operably associated for moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks, said magnetic head having a spacing between the gap, and the leading edge substantially equal to b ÷ Sin θ where b is substantially equal to the spacing between the servo tracks and θ is substantially equivalent to the inclined angle of the data tracks.
Claim 6
Dependent Claim
129 words
Apparatus for reducing defects in the reproduced servo envelopes of a recorder comprising: a length of magnetic media having servo tracks thereon for track following and inclined data tracks; said servo tracks are parallel to an elongated edge of said length of magnetic media; a magnetic head, having a core geometry with a sharp leading edge a trailing edge and a gap therebetween, operably associated for moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks, said magnetic head having a spacing between the gap, and the leading edge substantially equal to b ÷ Sin θ where b is substantially equal to the spacing between the servo tracks and θ is substantially equivalent to the inclined angle of the data tracks.
Claim 7
Dependent Claim
154 words
An improved magnetic head, for a magnetic recorder in which track following is maintained from the amplitude of signals derived from prerecorded servo indicia located in servo tracks: the magnetic head moving transversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks; said magnetic head having: a center pole piece; a first support relief being operably connected to said center pole piece; a first gap being formed by the center pole piece and the first support relief; first coil operably seated on said first relief; a second support relief operably connected to said center pole piece; a second gap being formed by the center pole piece and the second relief; said second gap being spaced from the first gap a distance substantially equivalent to the effective spacing between servo tracks at the angle of traverse; and a second coil being operably positioned on the second support relief.
Claim 8
Dependent Claim
154 words
An improved magnetic head, for a magnetic recorder in which track following is maintained from the amplitude of signals derived from prerecorded servo indicia located in servo tracks: the magnetic head moving transversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks; said magnetic head having: a center pole piece; a first support relief being operably connected to said center pole piece; a first gap being formed by the center pole piece and the first support relief; first coil operably seated on said first relief; a second support relief operably connected to said center pole piece; a second gap being formed by the center pole piece and the second relief; said second gap being spaced from the first gap a distance substantially equivalent to the effective spacing between servo tracks at the angle of traverse; and a second coil being operably positioned on the second support relief.
Claim 9
Dependent Claim
17 words
The device as claimed in claim 4 where the first gap is a read and/or write gap.
Claim 10
Dependent Claim
15 words
The device as claimed in claim 4 where the second gap is an erase gap.
Claim 11
Dependent Claim
93 words
A magnetic transducer, for cooperating with a relatively moving recording surface in which longitudinal servo tracks are prerecorded and are used for accessing data in tracks inclined to the servo tracks, said transducer moving transversely across the servo tracks at a predetermined angle to the longitudinal axis of said servo tracks, comprising: a dual gap magnetic head; said dual gap head having a center core pole piece for separating the gaps and having an effective separating distance substantially equivalent to the spacing between the longitudinal servo tracks at the angle of head traverse.
Claim 12
Dependent Claim
93 words
A magnetic transducer, for cooperating with a relatively moving recording surface in which longitudinal servo tracks are prerecorded and are used for accessing data in tracks inclined to the servo tracks, said transducer moving transversely across the servo tracks at a predetermined angle to the longitudinal axis of said servo tracks, comprising: a dual gap magnetic head; said dual gap head having a center core pole piece for separating the gaps and having an effective separating distance substantially equivalent to the spacing between the longitudinal servo tracks at the angle of head traverse.
Claim 13
Dependent Claim
29 words
The device as claimed in claim 7 wherein one of the gap's widths is such that a null in the gap loss function is being created at servo density.
Claim 14
Dependent Claim
18 words
The device as claimed in claim 8 wherein the gap width is being equal to approximately 581 microinches.
Claim 15
Dependent Claim
169 words
A dual gap magnetic transducer for use with an elongated length of magnetic media having adjacent servo tracks thereon, with servo indicia in said tracks, said transducer moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks, comprising in combination: a center pole piece; a first support relief connected to said center pole piece; a first gap formed by the center pole piece and the first support relief; said gap having a predetermined width to create a null in the gap loss function at the density of the servo indicia in said servo tracks; first coil operably seated on said first relief; a second support relief operably connected to said center pole piece; a second gap formed by the center pole piece and the second relief; said second gap being spaced from the first gap a distance substantially equivalent to the spacing between servo tracks at the angle of head traverse; and a second coil positioned on the second support relief.
Claim 16
Dependent Claim
169 words
A dual gap magnetic transducer for use with an elongated length of magnetic media having adjacent servo tracks thereon, with servo indicia in said tracks, said transducer moving traversely across the servo tracks at a predetermined angle to the longitudinal axis of the servo tracks, comprising in combination: a center pole piece; a first support relief connected to said center pole piece; a first gap formed by the center pole piece and the first support relief; said gap having a predetermined width to create a null in the gap loss function at the density of the servo indicia in said servo tracks; first coil operably seated on said first relief; a second support relief operably connected to said center pole piece; a second gap formed by the center pole piece and the second relief; said second gap being spaced from the first gap a distance substantially equivalent to the spacing between servo tracks at the angle of head traverse; and a second coil positioned on the second support relief.
References Cited (Backward Citations)
US3049698A
Cited
US3964094A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-09 | 1982-10-09 | 1983-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-09 | 1986-10-09 | 1987-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-09 | 1990-10-09 | 1991-04-10 | $7700.00 | Window Closed / Lapsed |