US4017966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a magnetic head having a relatively large air-gap and a good resistance to mechanical wear
Assignee: Thales SA
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Filing: 1975-08-22
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Granted: 1977-04-19
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Expires: 1995-08-22
Abstract
Abstract A method of manufacturing a magnetic head, with a relatively large gap for reading, for instance, magnetic cards, and having a good resistance to mechanical wear, is provided. The head comprises two members with flat and parallel faces, made of a spinel ferrite having a high Curie temperature, encompassing a layer of non magnetic ferrite, 10 to 50 micrometers in thickness, deposited by silk-screen printing on one or both of the mutually opposite flat faces. The assembly is then bonded by sintering under pressure.
Inventors
- 👤 Antoinette Morell
- 👤 Jean Nicolas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/23; G11B5/235; G11B5/133; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49048; Y10T29/49055
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
233 words
A method of manufacturing a magnetic head assembly, including a U-shaped component consisting of a pair of magnetic ferrite sections, each of them having at least one flat face, and a gap, serving as an air-gap, consisting of a non-magnetic ferrite layer interposed between said flat faces, said method comprising the steps of: cutting a disc of magnetic ferrite material into at least two slices having two large opposite faces and grinding them so as to achieve parallelism therebetween of the order of approximately 10 microns; preparing a powder of zinc and iron oxides able to yield by sintering a non-magnetic ferrite, and mixing the same with a binder so as to form a paste; depositing a layer of said paste by silk-screen printing on one face of at least one of said slices, and drying said layer so as to eliminate the binder; bonding said two slices together, by sintering the same under pressure, for obtaining a composite member in which said layer in sandwiched between the two slices; and machining said composite member by a) cutting said member for obtaining at least one elongate bar which is a rectangular parallelepiped; b) drilling and grinding said bar in the longitudinal direction so as to obtain an elongate U-shaped block; and c) transversely cutting said block for obtaining a series of U-shaped components, one of which is to be used in said assembly.
Claim 2
Independent Claim
233 words
A method of manufacturing a magnetic head assembly, including a U-shaped component consisting of a pair of magnetic ferrite sections, each of them having at least one flat face, and a gap, serving as an air-gap, consisting of a non-magnetic ferrite layer interposed between said flat faces, said method comprising the steps of: cutting a disc of magnetic ferrite material into at least two slices having two large opposite faces and grinding them so as to achieve parallelism therebetween of the order of approximately 10 microns; preparing a powder of zinc and iron oxides able to yield by sintering a non-magnetic ferrite, and mixing the same with a binder so as to form a paste; depositing a layer of said paste by silk-screen printing on one face of at least one of said slices, and drying said layer so as to eliminate the binder; bonding said two slices together, by sintering the same under pressure, for obtaining a composite member in which said layer in sandwiched between the two slices; and machining said composite member by a) cutting said member for obtaining at least one elongate bar which is a rectangular parallelepiped; b) drilling and grinding said bar in the longitudinal direction so as to obtain an elongate U-shaped block; and c) transversely cutting said block for obtaining a series of U-shaped components, one of which is to be used in said assembly.
Claim 3
Dependent Claim
70 words
A method as claimed in claim 1, wherein: said magnetic ferrite material is a spinel structure polycrystalline ferrite in the composition of which there is Ni and Zn and in the manufacture of which there is a step of sintering under pressure; and said non-magnetic ferrite satisfies the formula Zn Fe 2 O 4 and is a polycrystalline obtained by sintering under pressure in the course of said bonding operation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-18 | 1980-10-18 | 1981-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-18 | 1984-10-18 | 1985-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-18 | 1988-10-18 | 1989-04-19 | $7700.00 | Window Closed / Lapsed |