US3854199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of magnetic transducing heads
Assignee: Fujitsu Services Ltd
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Filing: 1973-04-13
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Granted: 1974-12-17
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Expires: 1993-04-13
Abstract
Abstract A magnetic head production process is described which involves threading apertured laminations on to a centre member to form a bonded stack, machining opposite sides of the stack, bonding a Cshaped core member in spaced relation to each of the sides and machining a further surface on the bonded assembly, the further surface constituting the working face of the finished head, and having a pair of magnetic gaps transverse of the working surface, with a portion of the centre member exposed in the surface and lying between the gaps.
Inventors
- 👤 P Ridgway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/265; G11B5/147; G11B5/1475; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49048; Y10T29/49055
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
197 words
A method of manufacture of a magnetic transducing head including the steps of providing a first member; providing a plurality of magnetic laminations each with an aperture therein, the apertures being aligned on a common axis; assembling the laminations on to the first member, the first member passing through the apertures of all the laminations; bonding the laminations to one another and to the first member to form an aligned stack; forming two flat parallel surfaces on opposite edges of the stack; forming an assembly by bonding two magnetic laminar C-shaped members, each terminating in a pair of co-planar surfaces, one to each of said flat surfaces of the stack with said co-planar surfaces of each C-shaped member being spaced from the respective flat surface to which it is bonded, the first member lying between the-C-shaped members, the laminations of the stack and the laminations of the C-shaped members lying in parallel planes; removing material from the bonded assembly to form a face parallel to said common axis, the first member being at least partially exposed on the face so formed to produce a surface having two magnetic gaps respectively between the Cshaped members and the stack.
Claim 2
Independent Claim
197 words
A method of manufacture of a magnetic transducing head including the steps of providing a first member; providing a plurality of magnetic laminations each with an aperture therein, the apertures being aligned on a common axis; assembling the laminations on to the first member, the first member passing through the apertures of all the laminations; bonding the laminations to one another and to the first member to form an aligned stack; forming two flat parallel surfaces on opposite edges of the stack; forming an assembly by bonding two magnetic laminar C-shaped members, each terminating in a pair of co-planar surfaces, one to each of said flat surfaces of the stack with said co-planar surfaces of each C-shaped member being spaced from the respective flat surface to which it is bonded, the first member lying between the-C-shaped members, the laminations of the stack and the laminations of the C-shaped members lying in parallel planes; removing material from the bonded assembly to form a face parallel to said common axis, the first member being at least partially exposed on the face so formed to produce a surface having two magnetic gaps respectively between the Cshaped members and the stack.
Claim 3
Dependent Claim
83 words
A method of manufacture as claimed in claim 1 including the step of forming said first member by interposing a first layer of high permeability magnetic material between two second layers of non-magnetic material, the first member then being positioned within the assembly so that the planes of the first and second layers lie at right angles to the planes of said laminations and perpendicular to said face, the first member being effective to form a magnetic screen between said two magnetic gaps.
Claim 4
Dependent Claim
105 words
A method as claimed in claim 1 including the steps of interposing non-magnetic spacers between a plurality of groups of said magnetic laminations when assembling the laminations on to the first member to form a plurality of aligned stacks separated by non-magnetic spacers; tnd interposing non-magnetic spacers between a corresponding plurality of groups of magnetic laminations of said C-shaped members; bonding said C-shaped members one to each of the flat surfaces with said groups of magnetic laminations aligned in opposing relationship so that upon carrying out the step Of removing material from the bonded assembly a plurality of pairs of aligned magnetic gaps are produced.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |