US3852812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Symmetrical direct current tunnel erasing
Assignee: Potter Instrument Co Inc
•
Filing: 1973-07-25
•
Granted: 1974-12-03
•
Expires: 1993-07-25
Abstract
Abstract A tunnel erase magnetic transducer head has a magnetic core with a read/write gap and a pair of tunnel erase gaps symmetrically positioned to erase opposite edges of a recorded track. The erase gaps provide magnetic fields of relatively opposite senses to reduce recorded track width.
Inventors
- 👤 F Reisfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:18
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/012; G11B5/02; G11B5/027; G11B5/03
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
104 words
In a magnetic transducer head of the type having a first magnetic core with a gap defining the width of a magnetic track to be recorded, a read/write coil on said first magnetic core, second and third magnetic cores having gaps positioned to erase opposite sides of said magnetic track, and erase coils on said second and third cores; the improvement comprising means for direct current energizing sAid erase coils and means interconnecting said energizing means and said erase coils for producing magnetic fields of opposite polarity at the respective gaps of said cores with respect to the lengthwise direction of said magnetic track.
Claim 2
Dependent Claim
104 words
In a magnetic transducer head of the type having a first magnetic core with a gap defining the width of a magnetic track to be recorded, a read/write coil on said first magnetic core, second and third magnetic cores having gaps positioned to erase opposite sides of said magnetic track, and erase coils on said second and third cores; the improvement comprising means for direct current energizing sAid erase coils and means interconnecting said energizing means and said erase coils for producing magnetic fields of opposite polarity at the respective gaps of said cores with respect to the lengthwise direction of said magnetic track.
Claim 3
Dependent Claim
144 words
In a tunnel erase magnetic transducer head of the type having a first magnetic core with a gap substantially defining the width of a magnetic track to be recorded, a read/write coil on said first core, second and third magnetic cores each having a gap and being mounted with their gap symmetrically disposed on opposite sides of the normal to the center of the gap of the first core for erasing opposite edges of a recorded track, and erase coils on said second and third core; the improvement comprising means for direct current energizing said erase cores and means for interconnecting said energizing means and said erase coils to produce equal and opposite polarity magnetic fields at their respective gaps with respect to the lengthwise direction of said recorded track whereby fringe erasure of a magnetic track recorded by said transducer head is symmetrical.
Claim 4
Dependent Claim
144 words
In a tunnel erase magnetic transducer head of the type having a first magnetic core with a gap substantially defining the width of a magnetic track to be recorded, a read/write coil on said first core, second and third magnetic cores each having a gap and being mounted with their gap symmetrically disposed on opposite sides of the normal to the center of the gap of the first core for erasing opposite edges of a recorded track, and erase coils on said second and third core; the improvement comprising means for direct current energizing said erase cores and means for interconnecting said energizing means and said erase coils to produce equal and opposite polarity magnetic fields at their respective gaps with respect to the lengthwise direction of said recorded track whereby fringe erasure of a magnetic track recorded by said transducer head is symmetrical.
Claim 5
Dependent Claim
32 words
The tunnel erase magnetic transducer head of claim 2 wherein the gaps of said second and third cores are coplanar and parallel to the plane of the gap of said first core.
Claim 6
Independent Claim
79 words
A system for recording magnetic tracks on a recording medium comprising transducer means, and means for providing relative movement between said transducer means and said recording medium, said transducer means comprising means for magnetically recording a signal on said medium to produce a magnetic track thereon, and direct current energized means for producing magnetic erasing fields of opposite polarity with respect to the lengthwise direction of the recorded track at opposite edges of said track to erase said edge.
Claim 7
Independent Claim
79 words
A system for recording magnetic tracks on a recording medium comprising transducer means, and means for providing relative movement between said transducer means and said recording medium, said transducer means comprising means for magnetically recording a signal on said medium to produce a magnetic track thereon, and direct current energized means for producing magnetic erasing fields of opposite polarity with respect to the lengthwise direction of the recorded track at opposite edges of said track to erase said edge.
Claim 8
Independent Claim
91 words
A method for magnetically recording a signal on a track on a recording medium comprising producing relative movement between a magnetic transducing means and said recording medium, energizing said transducing means with said signal to produce a recorded track on said recording medium, direct current energizing an edge erasing means to produce magnetic erasing fields of opposite polarity with respect to the lengthwise direction of said recorded track and on opposite edges of said track to erase edge portions of said track whereby fringe erasure of said magnetic track is symmetrical.
Claim 9
Independent Claim
91 words
A method for magnetically recording a signal on a track on a recording medium comprising producing relative movement between a magnetic transducing means and said recording medium, energizing said transducing means with said signal to produce a recorded track on said recording medium, direct current energizing an edge erasing means to produce magnetic erasing fields of opposite polarity with respect to the lengthwise direction of said recorded track and on opposite edges of said track to erase edge portions of said track whereby fringe erasure of said magnetic track is symmetrical.
References Cited (Backward Citations)
US3485958A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |