US3621153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic read/write head with partial gap and method of making
Assignee: International Business Machines Corp
•
Filing: 1969-12-22
•
Granted: 1971-11-16
•
Expires: 1989-12-22
Abstract
Abstract A magnetic head having a plurality of read/write tracks, each track being formed of a single continuous lamina of highpermeability magnetic material which is wrapped around the edge of a support substrate and extends through an opening in the substrate. A coil encircles one leg of each of the lamina, the coils being alternately placed on opposite sides of the substrate to allow minimum space between the tracks. A magnetic gap extends less than the complete distance across each individual lamina parallel to the edge of the substrate. The electrical characteristics of each individual magnetic gap are monitored as the gap is cut. The cutting operation is terminated in accordance with the value of an electrical characteristic to obtain uniform gap characteristics for each of the gaps. The lateral position of the cut is adjusted in accordance with the value of an electrical characteristic to obtain longitudinal alignment of all of the gaps.
Inventors
- 👤 John W Wenner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/29; G11B5/1272; G11B5/187; G11B5/23; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49004; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49036; Y10T29/49048
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A magnetic head, comprising: a nonmagnetic support substrate having opening means adjacent one edge thereof, a single continuous lamina of magnetic material extending through said opening means in said substrate and encircling said edge of said substrate, a read/write coil encircling a leg of said lamina on one side of said substrate between said opening and said edge of said substrate, and an elongated magnetic gap in said lamina substantially parallel to said edge of said substrate, said gap length being less than the width of said lamina.
Claim 2
Dependent Claim
88 words
A magnetic head, comprising: a nonmagnetic support substrate having opening means adjacent one edge thereof, a single continuous lamina of magnetic material extending through said opening means in said substrate and encircling said edge of said substrate, a read/write coil encircling a leg of said lamina on one side of said substrate between said opening and said edge of said substrate, and an elongated magnetic gap in said lamina substantially parallel to said edge of said substrate, said gap length being less than the width of said lamina.
Claim 3
Dependent Claim
39 words
A magnetic head as defined in claim 1 wherein said lamina is formed of a sheet of magnetic material whose ends are fastened as by welding to form a continuous loop which encircles and is supported by said substrate.
Claim 4
Dependent Claim
31 words
A magnetic head as defined in claim 1 wherein said magnetic gap is formed in said lamina such that a portion of said lamina bridges each longitudinal end of said gap.
Claim 5
Dependent Claim
83 words
A magnetic head as defined in claim 1 including: a plurality of similar individual continuous lamina of magnetic material spaced from each other along said edge of said substrate and extending through said opening in said substrate, a plurality of similar coils, each encircling a leg of one of said lamina, and an elongated magnetic gap in each of said pluralities of lamina substantially parallel to said edge of said substrate and each extending a distance less than the width of the lamina.
Claim 6
Dependent Claim
33 words
A magnetic head as defined in claim 4 wherein said magnetic gap is centrally located in each of said lamina with a portion of said lamina bridging each longitudinal end of said gap.
Claim 7
Dependent Claim
35 words
A magnetic head as defined in claim 5 wherein the size of the magnetic gap in each of said lamina is controlled such that the resulting plurality of individual magnetic gaps have similar electrical characteristics.
Claim 8
Dependent Claim
20 words
A magnetic head as defined in claim 6, wherein said coils are alternately placed on opposite sides of said substrate.
Claim 9
Independent Claim
93 words
The method of making a magnetic head comprising the steps of: encircling a single lamina of magnetic material with a coil, wrapping the lamina around the edge of a support substrate so that the ends of said lamina engage, welding the ends of the lamina, cutting a magnetic gap in said lamina substantially parallel to said edge of said substrate and of a length less than the width of said lamina, monitoring an electrical characteristic of said gap during the cutting process, and terminating the cutting process in accordance with said electrical characteristic.
Claim 10
Independent Claim
93 words
The method of making a magnetic head comprising the steps of: encircling a single lamina of magnetic material with a coil, wrapping the lamina around the edge of a support substrate so that the ends of said lamina engage, welding the ends of the lamina, cutting a magnetic gap in said lamina substantially parallel to said edge of said substrate and of a length less than the width of said lamina, monitoring an electrical characteristic of said gap during the cutting process, and terminating the cutting process in accordance with said electrical characteristic.
Claim 11
Independent Claim
115 words
The method of making a magnetic head having a plurality of read/write gaps, comprising the steps of: encircling each of a plurality of individual lamina of magnetic material with a coil, wrapping said laminae around the edge of a support substrate in spaced relationship so that the ends of each individual lamina overlap, welding the ends of each of said lamina, cutting a magnetic gap in each of said lamina substantially parallel to said edge of said substrate and of a length less than the width of said lamina, monitoring an electrical characteristic of each individual magnetic gap as it is cut, and terminating the cutting operation when said electrical characteristic reaches a given value.
Claim 12
Independent Claim
115 words
The method of making a magnetic head having a plurality of read/write gaps, comprising the steps of: encircling each of a plurality of individual lamina of magnetic material with a coil, wrapping said laminae around the edge of a support substrate in spaced relationship so that the ends of each individual lamina overlap, welding the ends of each of said lamina, cutting a magnetic gap in each of said lamina substantially parallel to said edge of said substrate and of a length less than the width of said lamina, monitoring an electrical characteristic of each individual magnetic gap as it is cut, and terminating the cutting operation when said electrical characteristic reaches a given value.
Claim 13
Dependent Claim
80 words
The method of making a magnetic head as defined in claim 9, including the steps of: monitoring an electrical signal received as a result of a magnetic gap in one of said lamina, comparing said electrical signal with the signal received as a result of a magnetic gap which is in the process of being cut, and controlling the position of the cut in accordance with said comparison in order to maintain the magnetic gaps in said laminae in alignment.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |