US3357005A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple magnetic head assembly
Assignee: US Philips Corp
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Filing: 1965-02-18
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Granted: 1967-12-05
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Expires: 1985-02-18
Abstract
No abstract record available.
Inventors
- 👤 Geurst Jan Albert
- 👤 Walther George Ludwig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:12
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/265; G11B5/29
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
164 words
A DEVICE FOR REDUCING OR ELIMINATING THE RELATIVE INFLUENCE OF THE PARTS OF A MULTIPLE MAGNETIC HEAD FOR RECORDING AND REPRODUCING ONE OR MORE PARALLEL RECORDS ON A CARRIER PROVIDED WITH MAGNETISABLE MATERIAL, SAID HEAD CONSISTING OF AT LEAST TWO INTERCONNECTED MAGNETIC CIRCUITS, ONE FOR RECORDING AND ONE FOR REPRODUCING, LYING ONE AFTER THE OTHER AND CONSISTING EACH OF AT LEAST TWO PORTIONS OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL, THERE BEING PROVIDED BETWEEN SAID TWO PORTIONS A USEFUL GAP FILLED OUT WITH NON-MAGNETISABLE MATERIAL, SAID NON-MAGNETISABLE MATERIAL BONDING THE TWO PORTIONS TO EACH OTHER, AT LEAST ONE PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL ARRANGED BETWEEN THE MAGNETIC CIRCUITS, A PLATE OF ELECTRICALLY CONDUCTING, NON-MAGNETISABLE MATERIAL ARRANGED BETWEEN EACH INDIVIDUAL MAGNETIC CIRCUIT AND A PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL, AND MEANS FOR IMPARTING TO THE PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL A MAGNETIC POTENTIAL WHICH IS SUBSTANTIALLY EQUAL TO THAT PORTION OF THE RECORDING CIRCUIT WHICH IS LOCATED ON THE OUTER SIDE OF THE HEAD.
Claim 2
Independent Claim
164 words
A DEVICE FOR REDUCING OR ELIMINATING THE RELATIVE INFLUENCE OF THE PARTS OF A MULTIPLE MAGNETIC HEAD FOR RECORDING AND REPRODUCING ONE OR MORE PARALLEL RECORDS ON A CARRIER PROVIDED WITH MAGNETISABLE MATERIAL, SAID HEAD CONSISTING OF AT LEAST TWO INTERCONNECTED MAGNETIC CIRCUITS, ONE FOR RECORDING AND ONE FOR REPRODUCING, LYING ONE AFTER THE OTHER AND CONSISTING EACH OF AT LEAST TWO PORTIONS OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL, THERE BEING PROVIDED BETWEEN SAID TWO PORTIONS A USEFUL GAP FILLED OUT WITH NON-MAGNETISABLE MATERIAL, SAID NON-MAGNETISABLE MATERIAL BONDING THE TWO PORTIONS TO EACH OTHER, AT LEAST ONE PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL ARRANGED BETWEEN THE MAGNETIC CIRCUITS, A PLATE OF ELECTRICALLY CONDUCTING, NON-MAGNETISABLE MATERIAL ARRANGED BETWEEN EACH INDIVIDUAL MAGNETIC CIRCUIT AND A PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL, AND MEANS FOR IMPARTING TO THE PLATE OF SINTERED, OXIDIC, FERROMAGNETIC MATERIAL A MAGNETIC POTENTIAL WHICH IS SUBSTANTIALLY EQUAL TO THAT PORTION OF THE RECORDING CIRCUIT WHICH IS LOCATED ON THE OUTER SIDE OF THE HEAD.
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) | 1970-12-04 | 1971-06-05 | 1971-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-12-04 | 1975-06-05 | 1975-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-12-04 | 1979-06-05 | 1979-12-05 | $7700.00 | Window Closed / Lapsed |