US4242711A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilayer magnetic head core
Assignee: Nippon Gakki Co Ltd
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Filing: 1978-04-07
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Granted: 1980-12-30
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Expires: 1998-04-07
Abstract
Abstract In a metal-insulator alternate type multilayer head core usable for magnetic sound recording and reproducing, metallic component layers are connected to each other via one or more metallic interconnecting layers passing locally through insulating component layers in order to provide high effective permeability with minimized eddy current loss. In manufacturing, a metal-insulator alternate type multilayer construction including the metallic interconnecting layer or layers is subjected to sintering in order to avoid intermetal separation to be otherwise caused by cracking in the insulating layers.
Inventors
- 👤 Takeo Sata
- 👤 Masayuki Takamura
- 👤 Tomoo Yamagishi
- 👤 Toshiharu Hoshi
- 👤 Kenzaburo Iijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/147; G11B5/1475; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
93 words
A multilayer magnetic head core comprising a plurality of adjacent parallel layers, each layer having a given area of each major surface thereof and comprising an insulating material selected from the group consisting of alumina, magnesia and silica glass; and a unitary sintered mass comprising a low ductility metallic high permeability magnetic alloy material surrounding said layers and forming a plurality of mechanically and electrically interconnected magnetic layers contiguous with corresponding areas of said layers, said mass having a predetermined cross-sectional area in a plane parallel to the major surface of said layers.
Claim 2
Dependent Claim
93 words
A multilayer magnetic head core comprising a plurality of adjacent parallel layers, each layer having a given area of each major surface thereof and comprising an insulating material selected from the group consisting of alumina, magnesia and silica glass; and a unitary sintered mass comprising a low ductility metallic high permeability magnetic alloy material surrounding said layers and forming a plurality of mechanically and electrically interconnected magnetic layers contiguous with corresponding areas of said layers, said mass having a predetermined cross-sectional area in a plane parallel to the major surface of said layers.
Claim 3
Dependent Claim
22 words
The head core according to claim 1, wherein the ratio of said given area to said predetermined area is at least 40%.
Claim 4
Dependent Claim
16 words
The head core according to claim 1, wherein said magnetic alloy material comprises sendust or alperm.
References Cited (Backward Citations)
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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) | 1983-12-30 | 1984-06-30 | 1984-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-30 | 1988-06-30 | 1988-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-30 | 1992-06-30 | 1992-12-30 | $7700.00 | Window Closed / Lapsed |