US3634933A
Expired / Lapsed
US
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Magnetic head method
Assignee: RCA Corp
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Filing: 1969-12-23
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Granted: 1972-01-18
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Expires: 1989-12-23
Abstract
Abstract An integral multihead magnetic transducer and method of manufacturing the same which is for example suitable for use in contact or noncontact disc recording. The transducer is comprised of blocks of preferred magnetic material having desired grooved shape and surface smoothness which are united and gap-filled by stipulated nonmagnetic materials to form a loaf. In one embodiment a nonmagnetic base is affixed to the loaf from which selected portions are removed to form an integral head assembly having a series of recording heads at spaced intervals. For certain applications the nonmagnetic base may be dispensed with, in which case selected pieces of the loaf are removed at spaced intervals with the remaining portions providing the backing and structural support for the resultant series of magnetic heads. In either case a multiple transducer is provided with accurately located heads and perfectly aligned recording gaps.
Inventors
- 👤 Joseph John Hanak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:41
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; Y10T29/49036; Y10T29/49039; Y10T29/49048; Y10T29/49053
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
A method for manufacturing a multiple magnetic head transducer assembly of the type consisting of a member formed of magnetic material, with said member having in a surface thereof a gap extending partially through said member and a nonmagnetic base member comprising the steps of: a. polishing to an optical finish both the surface of said member which is opposite to said surface containing said gap and a surface of said base member; b. then positioning said polished surfaces in facing relation with a bonding agent interposed therebetween; c. then placing said last-mentioned combination in a vacuum at a raised temperature; d. then exerting pressure on said load and said base in said vacuum, said pressure urging the polished surfaces together to form a bond therebetween; and e. then removing at spaced intervals along said base selected portions of said member, said removed portions including corresponding portions of said gapped surface, to form a multiple head assembly.
Claim 2
Independent Claim
157 words
A method for manufacturing a multiple magnetic head transducer assembly of the type consisting of a member formed of magnetic material, with said member having in a surface thereof a gap extending partially through said member and a nonmagnetic base member comprising the steps of: a. polishing to an optical finish both the surface of said member which is opposite to said surface containing said gap and a surface of said base member; b. then positioning said polished surfaces in facing relation with a bonding agent interposed therebetween; c. then placing said last-mentioned combination in a vacuum at a raised temperature; d. then exerting pressure on said load and said base in said vacuum, said pressure urging the polished surfaces together to form a bond therebetween; and e. then removing at spaced intervals along said base selected portions of said member, said removed portions including corresponding portions of said gapped surface, to form a multiple head assembly.
Claim 3
Dependent Claim
90 words
The method according to claim 1 wherein: a. said bonding agent is interposed by chemical vapor deposition of glass to a thickness of at least 500 angstrom units on each of said polished surfAces; b. said loaf and said base are placed in a vacuum of at least 10 2 Torr. at a temperature of at least 10* C. higher than the softening point of the glass bonding agent; and c. the pressure exerted is at least 2,000 pounds per square inch for a period of at least 10 minutes.
Claim 4
Dependent Claim
89 words
A method according to claim 1 wherein: a. said bonding agent is interposed by radiofrequency sputtering of glass to a thickness of at least 500 angstrom units on each of said polished surfaces; b. said loaf and said base are placed in a vacuum of at least 10 2 Torr. at a temperature of at least 10* C. higher than the softening point of the glass bonding agent; and c. the pressure exerted is at least 2,000 pounds per square inch for a period of at least 10 minutes.
Claim 5
Dependent Claim
161 words
In a method for manufacturing multiple head magnetic transducer assemblies including uniting at least two blocks of ferrite material by molecular transport, said blocks having a gap extending partially therebetween which is filled with a nonmagnetic gap-spacing material, the improvement comprising the steps of: a. polishing to an optical finish both the surface of the united blocks which is opposite the surface containing the gap and a surface of a base member; b. then depositing a layer of glass on each of said polished surfaces; c. then placing said united blocks and base member in a vacuum at a raised temperature with said glass-covered surfaces facing each other; d. then exerting a pressure on said blocks and said base uniting said glass-covered surfaces to form an integral bonded assembly; and e. then removing at spaced intervals along said base selected portions of said ferrite block material, said removed portions including corresponding portions of said gap, to form a multiple head assembly.
Claim 6
Dependent Claim
161 words
In a method for manufacturing multiple head magnetic transducer assemblies including uniting at least two blocks of ferrite material by molecular transport, said blocks having a gap extending partially therebetween which is filled with a nonmagnetic gap-spacing material, the improvement comprising the steps of: a. polishing to an optical finish both the surface of the united blocks which is opposite the surface containing the gap and a surface of a base member; b. then depositing a layer of glass on each of said polished surfaces; c. then placing said united blocks and base member in a vacuum at a raised temperature with said glass-covered surfaces facing each other; d. then exerting a pressure on said blocks and said base uniting said glass-covered surfaces to form an integral bonded assembly; and e. then removing at spaced intervals along said base selected portions of said ferrite block material, said removed portions including corresponding portions of said gap, to form a multiple head assembly.
Claim 7
Dependent Claim
50 words
A method for manufacturing multiple head magnetic transducer assemblies, according to claim 1, wherein said magnetic member having a gap in one surface thereof is formed of electrically conductive magnetic material; said selected portions of said magnetic member are removed by electrical machining to form a plurality of magnetic cores.
Claim 8
Dependent Claim
33 words
A method for manufacturing multiple head magnetic transducer assemblies according to claim 1, wherein said selected portions of said magnetic member are removed by laser machining to form a plurality of magnetic cores.
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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) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |