Patent US3249928A successfully refreshed from Google Patents.
US3249928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic transducer
Assignee: Unisys Corp
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Filing: 1961-09-22
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Granted: 1966-05-03
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Expires: 1981-09-22
Abstract
No abstract record available.
Inventors
- 👤 Fred C Curtis
- 👤 Michael I Behr
- 👤 Henry M Merrill
- 👤 Richard E Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:30
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/29
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
359 words
A READ-WRITE TRANSDUCER COMPRISING A SUBSTANTIALLY NON-MAGNETIC MEMBER MOUNTING A PLURALITY OF SIMILARLY CONSTRUCTED INDIVIDUALLY SHIELDED ELECTROMAGNETIC MODULAR ASSEMBLIES FOR EFFECTING A READING OPERATION IN DIFFERENT CHANNELS ON A MAGNETIC CARRIER, EACH OF SAID MODULAR ASSEMBLIES COMPRISING A PLURALITY OF INSULATIVELY STACKED, SUBSTANTIALLY U-SHAPED, LOW RELUCTANCE MAGNETIC LAMINATIONS AND SEPARATE ELECTRICAL WINDING MEANS WOUND ON EACH ARM OF SAID U-SHAPED MEMBER AND CONNECTED IN A SERIES AIDING RELATIONSHIP, SAID MODULAR ASSEMBLY BEING ARRANGED ON SAID NON-MAGNETIC BODY WITH AN END EXPOSED TO A MAGNETIC CARRIER, ANOTHER SUBSTANTIALLY NON-MAGNETIC MEMBER MOUNTING A PLURALITY OF SIMILARLY CONSTRUCTED INDIVIDUALLY SHIELDED ELECTROMAGNET MODULAR ASSEMBLIES FOR EFFECTING A WRITING OPERATION IN DIFFERENT CHANNELS ON A MAGNETIC CARRIER, EACH OF SAID WRITING MODULAR ASSEMBLIES COMPRISING A PLURALITY OF INSULATIVELY STACKED, SUBSTANTIALLY U-SHAPED, LOW RELUCTANCE MAGNETIC LAMINATIONS AND ELECTRICAL WINDING MEANS WOUND ON AN ARM OF SAID USHAPED MEMBER, SAID MODULAR ASSEMBLY BEING ARRANGED IN SAID NON-MAGNETIC MEMBER WITH AN END EXPOSED TO A MAGNETIC CARRIER, A DIVIDER BODY COMPRISING A PLURALITY OF ALTERNATELY ARRANGED ELECTROMAGNETIC AND ELECTROSTATIC SHIELDING MEMBERS HAVING AT LEAST A CENTRAL ELECTROSTATIC SHIELDING MEMBER AND A PAIR OF OUTER ELECTROSTATIC SHIELDING MEMBERS ARRANGED ON OPPOSITE SIDES OF SAID CENTRAL MEMBER AND SPACED THEREFROM BY AT LEAST A SINGLE ELECTROMAGNETIC SHIELDING MEMBER, A PAIR OF LOW RELUCTANCE MAGNETIC MEMBERS CARRIED BY SAID DIVIDING BODY AND ARRANGED ADJACENT ONE OF SAID OUTER SHIELDING MEMBERS, SAID PAIR OF MAGNETIC MEMBERS BEING DEFINED RELATIVE TO SAID ELONGATED MAGNETIC STRUCTURE TO PROVIDE A SUBSTANTIALLY CLOSED LOOP MAGNETIC PATH WHEN ASSEMBLIED TOGETHER, A NON-MAGNETIC MEMBER ARRANGED INTERMEDIATE SAID PAIR OF MAGNETIC MEMBERS AT THE MAGNETIC CARRIER EXPOSED END OF SAID DIVIDING BODY TO ISOLATE SAID ELECTROMAGNETIC SHIELDING MEMBERS FROM THE MAGNETIC CARRIER, A PAIR OF HIGH RELUCTANCE MEMBERS, MEANS FOR SECURING SAID PAIR OF BODIES TOGETHER ON OPPOSITE SIDES OF THE DIVIDER BODY WITH ONE OF THE HIGH RELUCTANCE MEMBERS SANDWICHED BETWEEN SAME AND ADJACENT THE MAGNETIC CARRIER EXPOSED END OF SAID MAGNETIC STRUCTURE, THE THUS SECURED TRANSDUCER ASSEMBLY BEING FURTHER DEFINED WHEREBY THE HIGH RELUCTANCE MEMBERS FUNCTION AS TRANSDUCING GAPS AND ARE ALIGNED TO PROVIDE A SIMULTANEOUS TRANSDUCING OPERATION ON THE SAME TRACK OF A MAGNETIC CARRIER.
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) | 1969-05-02 | 1969-11-01 | 1970-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-05-02 | 1973-11-01 | 1974-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-05-02 | 1977-11-01 | 1978-05-03 | $7700.00 | Window Closed / Lapsed |