US3999286A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making multitrack heads
Assignee: 3M Co
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Filing: 1975-06-11
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Granted: 1976-12-28
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Expires: 1995-06-11
Abstract
Abstract A multitrack recording head having a pair of ferrite combs whose teeth are separated at their tips by nonmagnetic gap spacers and whose bases are in abutting relationship. Each tooth of one comb has a wire coil for electrically transmitting signals to or from each track of the head.
Inventors
- 👤 Harvey J. Richardson
- 👤 Robert J. Youngquist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/29; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49048; Y10T29/49053; Y10T29/49055; Y10T29/49057; Y10T29/4906; Y10T29/49066
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
158 words
Method of making a multitrack magnetic recording head comprising the steps of a. forming a pair of ferrite combs, each having a plurality of teeth, the width of each tooth exceeding the spacing between adjacent teeth, one side of each tooth having a smooth front gap surface and a smooth rear gap surface which are aligned with like surfaces of a tooth of the other comb when the combs are juxtaposed, the rear gap surfaces of one comb being at the tips of its teeth and of the other comb being at its base, b. applying a wire coil to each tooth of said one comb, c. assembling the combs in juxtaposition with the paired rear gap surfaces in substantial contact with each other and the front gap surfaces separated by a nonmagnetic gap-spacer, d. removing the base of said one comb, and e. finishing the faces of the teeth adjacent the gap-spacer to afford good head-to-tape contact.
Claim 2
Dependent Claim
158 words
Method of making a multitrack magnetic recording head comprising the steps of a. forming a pair of ferrite combs, each having a plurality of teeth, the width of each tooth exceeding the spacing between adjacent teeth, one side of each tooth having a smooth front gap surface and a smooth rear gap surface which are aligned with like surfaces of a tooth of the other comb when the combs are juxtaposed, the rear gap surfaces of one comb being at the tips of its teeth and of the other comb being at its base, b. applying a wire coil to each tooth of said one comb, c. assembling the combs in juxtaposition with the paired rear gap surfaces in substantial contact with each other and the front gap surfaces separated by a nonmagnetic gap-spacer, d. removing the base of said one comb, and e. finishing the faces of the teeth adjacent the gap-spacer to afford good head-to-tape contact.
Claim 3
Dependent Claim
64 words
Method of making a multitrack recording head as defined in claim 1 including after step step the steps of d'. positioning the head in a conductive metal can, the face of which is formed with an opening to receive each pair of teeth, d". potting the head with thermosetting resin, and the face of the can is contoured in the course of step (e).
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) | 1979-12-28 | 1980-06-28 | 1980-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-28 | 1984-06-28 | 1984-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-28 | 1988-06-28 | 1988-12-28 | $7700.00 | Window Closed / Lapsed |