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US3810191A Expired / Lapsed US ⏱️ 0.0 years remaining

Multi-stylus through field recording head

Assignee: Northrop Grumman Innovation Systems LLC
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Filing: 1972-10-26
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Granted: 1974-05-07
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Expires: 1992-10-26
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Abstract

Abstract A magnetic recording head for recording on a magnetically responsive recording medium is arranged to incorporate a core structure of high magnetic retentivity material with individual core members being magnetized by a respective winding to produce a magnetic flux through the magnetically responsive recording medium. A flux return path is arranged to distribute the magnetic flux in the return path to a flux density level which is ineffective to produce a recording on a recording medium and is arranged to provide a flux return path on the other side of the recording medium from the magnetic recording head. A common bias and reset winding is arranged on the core structure and is separately energized to normally bias the core structure to a magnetic state which is ineffective to produce a recording on the recording medium during the absence of a signal on the individual windings on the core members and to reset the core structure to a non-recording state after the core members have been placed in a recording state by a signal applied to the respective windings on the core members.

Inventors

  • 👤 N Stauffer

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 10:07
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278; G11B5/48; G11B5/49; G11B5/4969

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 216 words
A magnetic recording head comprising a first magnetic core member having a first end face of a predetermined surface area and a second end face spaced from said first end face and being in a common plane therewith while having a predetermined surface area substantially greater than said surface area of said first end face, whereby a magnetic flux concentration insufficient to cause recording is associated with said second end face said first magnetic core member being made of a high magnetic retentivity characteristic material, an energizing winding wound on said magnetic core member and arranged to be connected to a source of an energizing signal suitable for producing a magnetic flux from said first and second end faces, a bias and reset winding wound on said magnetic core and arranged to be connected to a source of a bias and reset signal suitable for normally biasing said first core member into a non-magnetic flux producing state and to reset said core member into said state after the application and termination of an energizing signal to said energizing winding, and a second core member forming a magnetic flux return path and being located adjacent to said first and second end faces and separated therefrom by a distance sufficient to allow a recording medium to pass therebetween.
Claim 2
Dependent Claim 216 words
A magnetic recording head comprising a first magnetic core member having a first end face of a predetermined surface area and a second end face spaced from said first end face and being in a common plane therewith while having a predetermined surface area substantially greater than said surface area of said first end face, whereby a magnetic flux concentration insufficient to cause recording is associated with said second end face said first magnetic core member being made of a high magnetic retentivity characteristic material, an energizing winding wound on said magnetic core member and arranged to be connected to a source of an energizing signal suitable for producing a magnetic flux from said first and second end faces, a bias and reset winding wound on said magnetic core and arranged to be connected to a source of a bias and reset signal suitable for normally biasing said first core member into a non-magnetic flux producing state and to reset said core member into said state after the application and termination of an energizing signal to said energizing winding, and a second core member forming a magnetic flux return path and being located adjacent to said first and second end faces and separated therefrom by a distance sufficient to allow a recording medium to pass therebetween.
Claim 3
Dependent Claim 15 words
A magnetic recording head as set forth in claim 1 wherein said material is ferrite.
Claim 4
Dependent Claim 57 words
A magnetic recording head as set forth in claim 1 wherein said first end face is divided into a plurality of separate core projections forming recording stylii and said energizing winding means includes a separate winding on each of said projections and said bias and reset winding is arranged to be common to all of said projections.
Claim 5
Dependent Claim 28 words
A magnetic recording head as set forth in claim 1 wherein said second core member is made from a low magnetic retentivity and low magnetic reluctance characteristic material.
Claim 6
Dependent Claim 16 words
A magnetic recording head as set forth in claim 4 wherein said material is soft iron.

References Cited (Backward Citations)

US3164628A Cited
US3414893A Cited
US3432838A Cited
US3492670A Cited
US3683382A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-05-06 1977-11-05 1978-05-07 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-05-06 1981-11-05 1982-05-07 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-05-06 1985-11-05 1986-05-07 $7700.00 Window Closed / Lapsed

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