Patent US4700253A successfully refreshed from Google Patents.
US4700253A
Expired / Lapsed
US
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Slanted pole head for magnetic recording
Assignee: 3M Co
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Filing: 1983-11-22
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Granted: 1987-10-13
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Expires: 2003-11-22
Abstract
Abstract A magnetic pole head for recording and playback is described. Its features, as illustrated in FIG. 1 are: a high permeability core 1, a magnetic field producing means 3, and an acute angle φ between the bottom surface and side surface at the trailing portion of the head (i.e. the portion which influences the recording medium 5 last). It has been found that this improved pole head significantly increases the derivative of vertical magnetic field intensity with respect to lateral distance. This increase in the rate at which vertical field intensity changes will allow for higher density perpendicular recording than is feasible with conventional vertical heads.
Inventors
- 👤 Joel A. Gerber
- 👤 Jerry A. Sievers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1278
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
164 words
In a magnetic recording or playback apparatus, the combination of: (1) a magnetic recording medium to be transported by the apparatus close to a head; and (2) a magnetic pole head comprising: a. a magnetic field producing means; and b. a magnetizable core associated with the magnetic field producing means and defined as a pole having: (i) bottom surface; (ii) at least one side surface which intersects said bottom surface; (iii) an acute included angle greater than 15° existing between at least one side surface and the bottom surface; (iv) a sharp gradient edge at the portion of the intersection of the side and bottom surfaces nearest the location where the smallest included angle is formed; and (v) a signal averaging edge at the portion of the intersection of the side and bottom surfaces opposite the sharp gradient edge; said magnetic pole head being oriented so that the signal averaging edge is the leading edge, and the sharp gradient edge is the trailing edge.
Claim 2
Dependent Claim
164 words
In a magnetic recording or playback apparatus, the combination of: (1) a magnetic recording medium to be transported by the apparatus close to a head; and (2) a magnetic pole head comprising: a. a magnetic field producing means; and b. a magnetizable core associated with the magnetic field producing means and defined as a pole having: (i) bottom surface; (ii) at least one side surface which intersects said bottom surface; (iii) an acute included angle greater than 15° existing between at least one side surface and the bottom surface; (iv) a sharp gradient edge at the portion of the intersection of the side and bottom surfaces nearest the location where the smallest included angle is formed; and (v) a signal averaging edge at the portion of the intersection of the side and bottom surfaces opposite the sharp gradient edge; said magnetic pole head being oriented so that the signal averaging edge is the leading edge, and the sharp gradient edge is the trailing edge.
Claim 3
Dependent Claim
29 words
The combination of claim 1 in which the trailing edge is a straight line and the leading edge is a curved line intersecting both ends of the trailing edge.
Claim 4
Dependent Claim
181 words
In a magnetic recording or playback apparatus, the conbination of: (A) a magnetic recording medium to be transported by the apparatus close to a head; and (B) a magnetic pole head subassembly comprising: (1) a magnetic pole head comprising: (a) a magnetic field producing means; and (b) a magnetizable core associated with the magnetic field producing means and defined as a pole having: (i) a bottom surface; (ii) at least one side surface which intersects said bottom surface; (iii) an acute included angle greater than 15° between at least one side surface and the bottom surface; (iv) a sharp gradient edge at the portion of the intersection of the side and bottom surfaces nearest the location where the smallest included angle in formed; and (v) a signal averaging edge at the portion of the intersection of the side and bottom surfaces opposite the sharp gradient edge; and (2) a non-magnetic material in which the pole head is encased; said subassembly being oriented so that the signal averaging edge is the leading edge, and the sharp gradient edge is the trailing edge.
Claim 5
Dependent Claim
181 words
In a magnetic recording or playback apparatus, the conbination of: (A) a magnetic recording medium to be transported by the apparatus close to a head; and (B) a magnetic pole head subassembly comprising: (1) a magnetic pole head comprising: (a) a magnetic field producing means; and (b) a magnetizable core associated with the magnetic field producing means and defined as a pole having: (i) a bottom surface; (ii) at least one side surface which intersects said bottom surface; (iii) an acute included angle greater than 15° between at least one side surface and the bottom surface; (iv) a sharp gradient edge at the portion of the intersection of the side and bottom surfaces nearest the location where the smallest included angle in formed; and (v) a signal averaging edge at the portion of the intersection of the side and bottom surfaces opposite the sharp gradient edge; and (2) a non-magnetic material in which the pole head is encased; said subassembly being oriented so that the signal averaging edge is the leading edge, and the sharp gradient edge is the trailing edge.
Claim 6
Dependent Claim
34 words
The combination recited in claim 3, further comprising a non-magnetic housing into which the magnetic pole head subassembly has been installed, said housing having been given the final desired shape and pole head exposure.
References Cited (Backward Citations)
US2245286A
Cited
US2360625A
Cited
US2562707A
Cited
US2501126A
Cited
US3046358A
Cited
US3334192A
Cited
US3427409A
Cited
GB1186310A
Cited
US4091429A
Cited
JPS539110A
Cited
SU581495A1
Cited
US4222084A
Cited
JPS5441710A
Cited
US4251842A
Cited
US4210946A
Cited
JPS5474718A
Cited
JPS5567932A
Cited
JPS55113122A
Cited
US4314298A
Cited
JPS578621A
Cited
JPS57117119A
Cited
EP0070907A1
Cited
JPS57179922A
Cited
JPS5853013A
Cited
JPS58215713A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |