US4249301A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for manufacturing magnetic transducing heads
Assignee: Data Recording Instrument Co Ltd
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Filing: 1979-08-10
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Granted: 1981-02-10
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Expires: 1999-08-10
Abstract
Abstract A method of forming a magnetic ferrite element for the core of a magnetic transducing head is disclosed in which spacers for determining the length of a non-magnetic gap are formed by providing a masking layer at locations on a surface of the element at which the spacers are required and eroding away the masking layer and the unmasked portions of the surface by an ion beam to produce a new surface having a spacer projecting at each of the locations by a distance determined by the relative rates of erosion of the ferrite and the masking material and by the predetermined thickness of the masking layer.
Inventors
- 👤 John R. Cartwright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:35
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1871; G11B5/193; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49055; Y10T29/49057; Y10T29/49059
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
216 words
A method of manufacturing a magnetic core for a magnetic transducing head including the steps of providing a first magnetic member of ferrite material with a first planar surface; providing a layer of masking material having a predetermined thickness at each of two spaced apart positions on the first planar surface leaving a portion of the planar surface exposed; subjecting the exposed portion of the planar surface and the masking layers to an eroding action by an ion beam to remove material from the surface of the masking layers and from the exposed portion of the planar surface to produce a new planar surface on the first magnetic member and a spacer at each of said positions projecting from said new planar surface consisting at least partly of the ferrite material of the first magnetic member, the height of the spacers being determined by the relative rates of erosion of the ferrite material and masking material and by the predetermined thickness of the layer of masking material; then assembling the first magnetic member with a second magnetic member utilising the spacers to form a non-magnetic gap between the first and second members; bonding the members together with a glass material which fills the non-magnetic gap between the members and machining the assembly to remove the spacers.
Claim 2
Independent Claim
216 words
A method of manufacturing a magnetic core for a magnetic transducing head including the steps of providing a first magnetic member of ferrite material with a first planar surface; providing a layer of masking material having a predetermined thickness at each of two spaced apart positions on the first planar surface leaving a portion of the planar surface exposed; subjecting the exposed portion of the planar surface and the masking layers to an eroding action by an ion beam to remove material from the surface of the masking layers and from the exposed portion of the planar surface to produce a new planar surface on the first magnetic member and a spacer at each of said positions projecting from said new planar surface consisting at least partly of the ferrite material of the first magnetic member, the height of the spacers being determined by the relative rates of erosion of the ferrite material and masking material and by the predetermined thickness of the layer of masking material; then assembling the first magnetic member with a second magnetic member utilising the spacers to form a non-magnetic gap between the first and second members; bonding the members together with a glass material which fills the non-magnetic gap between the members and machining the assembly to remove the spacers.
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1, in which the masking material has a rate of erosion substantially equal to that of the ferrite material of the first magnetic member.
Claim 4
Dependent Claim
29 words
A method as claimed in claim 1, in which the masking material has a rate of erosion different to that of the ferrite material of the first magnetic member.
Claim 5
Dependent Claim
28 words
A method as claimed in claim 2, in which the eroding action by the ion beam is continued at least until all the masking material has been removed.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 3, in which the eroding action by the ion beam is continued at least until all the masking material has been removed.
Claim 7
Dependent Claim
24 words
A method claimed in claim 1 in which the masking material is sputtered on to the first magnetic member through apertures in a shield.
Claim 8
Dependent Claim
28 words
A method as claimed in claim 1 in which the masking material is provided at each position by a metal shim bonded on to the first magnetic member.
Claim 9
Dependent Claim
26 words
A method as claimed in claim 1 in which the glass material utilised in bonding the members together is a glass-ceramic material in its glass phase.
Claim 10
Dependent Claim
62 words
A method as claimed in claim 1 in which after bonding the members together, the bonded members are cut into a plurality of slices, each slice consisting of a portion of the first and of the second member bonded together by the glass in the gap between the portions, each slice providing a magnetic structure for use in a magnetic transducing head.
References Cited (Backward Citations)
US4045864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |