US3845550A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a magnetic head
Assignee: Ampex Corp
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Filing: 1973-10-01
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Granted: 1974-11-05
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Expires: 1993-10-01
Abstract
Abstract A method of constructing transducers is provided wherein a pair of rectangular ferrite blocks are processed to yield a plurality of magnetic heads, each having protective glass pockets formed thereon about the edges of the ferrite pole pieces which define the non-magnetic transducing gap. In its preferred form the process requires only a single glass bonding step which simultaneously bonds the material at the non-magnetic record/reproduce gap and forms the protective glass pockets. The glass pockets eliminate the detrimental effects of edge chipping and granular pull-outs adjacent the non-magnetic record/reproduce gap which tend to occur on magnetic heads fabricated from ferrites or other similarly brittle magnetic materials.
Inventors
- 👤 B Gooch
- 👤 E Schiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:12
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/133; G11B5/1335; G11B5/187; G11B5/1871; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49048; Y10T29/49055; Y10T29/49057
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
237 words
A method of constructing a magnetic transducer having a functional non-magnetic gap formed between a pair of complementary magnetic core halves, the steps comprising: forming a plurality of spaced parallel notches extending into a block of magnetic material only between intersecting surfaces thereof to define a plurality of outwardly facing lands, one of said surfaces being planar; forming an elongate groove in a plane surface of another block of magnetic material; holding said blocks in confronting spaced apart relationship with said planar surfaces in opposition so that a portion of said elongate groove confronts a portion of each of said notches at said lands to form communicating free space regions between the confronting blocks in said notches, in said groove and between the planar surfaces; filling the free space regions between said confronting planar surfaces, in said notches and in at least a part of said groove with glass, said glass forming an integral structural unit bonded to said planar surfaces and the walls of said notches and groove; and slicing said blocks along planes parallel to and substantially bisecting each of said spaced parallel notches to form a plurality of individual transducers each having a pair of magnetic core halves with a nonmagnetic glass gap therebetween and having glass pockets on the side of the glass gap, said glass pockets and the glass between said core halves, including said glass gap, forming an integral structural unit.
Claim 2
Independent Claim
237 words
A method of constructing a magnetic transducer having a functional non-magnetic gap formed between a pair of complementary magnetic core halves, the steps comprising: forming a plurality of spaced parallel notches extending into a block of magnetic material only between intersecting surfaces thereof to define a plurality of outwardly facing lands, one of said surfaces being planar; forming an elongate groove in a plane surface of another block of magnetic material; holding said blocks in confronting spaced apart relationship with said planar surfaces in opposition so that a portion of said elongate groove confronts a portion of each of said notches at said lands to form communicating free space regions between the confronting blocks in said notches, in said groove and between the planar surfaces; filling the free space regions between said confronting planar surfaces, in said notches and in at least a part of said groove with glass, said glass forming an integral structural unit bonded to said planar surfaces and the walls of said notches and groove; and slicing said blocks along planes parallel to and substantially bisecting each of said spaced parallel notches to form a plurality of individual transducers each having a pair of magnetic core halves with a nonmagnetic glass gap therebetween and having glass pockets on the side of the glass gap, said glass pockets and the glass between said core halves, including said glass gap, forming an integral structural unit.
Claim 3
Dependent Claim
50 words
The method of constructing a magnetic transducer in accordance with claim 1 wherein said notches are formed to extend from said planar surface to a second planar surface, said second planar surface being normal to said planar surface and coinciding with the face part of the transducers to be formed.
Claim 4
Dependent Claim
88 words
The method of constructing a magnetic transducer in accordance with claim 2 wherein said step of filling the free space regions is accomplished by the steps of disposing glass material within said elongate groove; heating said glass material to a temperature at which said glass material melts and flows into said free space regions between said confronting planar surfaces and into said free space regions in said notches; and cooling said glass material to bond said glass material to said planar surfaces and said walls of said notches.
Claim 5
Dependent Claim
104 words
The method of constructing a magnetic transducer in accordance with claim 3 wherein said step of holding said blocks in confronting spaced apart relationship is accomplished by positioning said blocks so that the bottom walls of said notches emerge from said planar surface of the first named block substantially midspan of the elongate groove carried by said planar surface of the second named block whereby a passage is formed between the upper region of said groove and the bottom wall of said notches for communicating glass melt between the free space region defined by said groove and said free space regions in said notches.
Claim 6
Dependent Claim
37 words
The method of constructing a magnetic transducer in accordance with claim 4 wherein said passage has a maximum dimension in the range of 2 to 5 thousandths of an inch in order to optimize capillary flow characteristics.
Claim 7
Dependent Claim
85 words
The method of constructing a magnetic transducer in accordance with claim 5 wherein the amount of glass material disposed within said groove is selected to substantially equal the volume of said free space regions between said confronting planar surfaces and said free space regions in said notches so that the heating and cooling steps result in the flow of glass material to said free space regions with the resultant formation of an open region in said groove defining a window adapted to receive transducer windings.
Claim 8
Dependent Claim
165 words
The method of constructing a magnetic transducer in accordance with claim 2, wherein said step of filling the free space regions is accomplished by the steps of disposing a spacer material between said confronting blocks above the level of said elongate groove to define the length of said functional non-magnetic gap; disposing glass material within said elongate groove; heating said glass material to a temperature at which said glass material melts and flows into said free space regions between confronting planar surfaces up to the level of said spacer material, and flows into said free space regions in said notches; cooling said glass material to bond said glass material to said walls of said notches and said planar surfaces; and lapping the second planar surface face part side of said combined blocks so that said spacer material is removed and said glass between said confronting planar surfaces is exposed to form a glass transducing gap on the face part of the transducers to be formed.
Claim 9
Dependent Claim
21 words
The method of constructing a magnetic transducer in accordance with claim 7 wherein said gap spacer material comprises a solid band.
Claim 10
Dependent Claim
47 words
The method of constructing a magnetic transducer in accordance with claim 8 wherein said gap spacer material is applied to at least one of said blocks prior to said holding step, said material being applied above the level of said elongate groove by a particle deposition process.
Claim 11
Dependent Claim
85 words
The method of constructing a magnetic transducer in accordance with claim 9 wherein the amount of glass material disposed within said groove is selected to substantially equal the volume of said free space regions between said confronting planar surfaces and the free space regions in said notches so that the heating and cooling steps result in the flow of glass material to said free space regions with the resultant formation of an open region in said groove defining a window adapted to receive transducer windings.
Claim 12
Dependent Claim
65 words
The method of constructing a magnetic transducer in accordance with claim 10 wherein said glass material is in the form of a plurality of glass rods disposed longitudinally within said groove, said glass rods having selectively different cross sections in order to minimize the storage space required by said glass material so that an undesirably large groove is not required in said second named block.
Claim 13
Dependent Claim
164 words
The method of constructing a magnetic transducer in accordance with claim 2 wherein said step of filling the free space regions is accomplished by the steps of disposing glass material within said elongate groove; disposing a glass shim between said confronting planar surfaces above the level of said elongate groove of said block, said glass shim having a melting temperature higher than the melting temperature of said glass material disposed in said elongate groove, and heating said glass material in said elongate groove to a temperature at which it melts and flows into said free space regions between said confronting planar surfaces up to the level of said glass shim and flows into the free space regions in said notches, said temperature being below the melting point of said glass shim so that said glass shim softens to create a bond between said glass shim and said confronting planar surfaces, and said glass shim and said glass material merge into an integral structural unit.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |