Patent US3239823A successfully refreshed from Google Patents.
US3239823A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Twin gap flux responsive head
Assignee: International Business Machines Corp
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Filing: 1962-05-16
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Granted: 1966-03-08
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Expires: 1982-05-16
Abstract
No abstract record available.
Inventors
- 👤 Chang David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:20
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/335
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
264 words
APPARATUS FOR SENSING A MAGNETIC RECORD, COMPRISING: (A) MAGNETIC READ HEAD MEANS; (B) A MAGNETIC RECORD MEMBER; (C) MEANS FOR RELATIVELY MOVING THE READ HEAD MEANS AND THE RECORD MEMBER; (D) SAID RECORD MEMBER CARRYING A MAGNETIC RECORD INCLUDING UNIDIRECTIONALLY MAGNETIZED POLES, EACH POLE BEING SPACED FROM THE NEXT ADJACENT POLE BY AT LEAST A PREDETERMINED DISTANCE IN THE DIRECTION OF SAID RELATIVE MOVEMENT; (E) SAID READ HEAD MEANS COMPRISING MAGNETIC CIRCUIT MEANS DEFINING TWO NON-MAGNETIC GAPS ADJACENT THE RECORD MEMBER, SAID GAPS BEING SPACED IN THE DIRECTION OF RELATIVE MOVEMENT BY A DISTANCE LESS THAN SAID PREDETERMINED DISTANCE, (F) SAID MAGNETIC CIRCUIT MEANS COMPRISING: (1) A FIRST LEG DEFINING THE OTHER SIDE OF THE GAP FIRST CROSSED BY A POLE ON THE RECORD MEMBER DURING SAID RELATIVE MOVEMENT; (2) A SECOND LEG DEFINING THE OUTER SIDE OF THE GAP LAST CROSSED BY THE RECORD MEMBER; (3) ADDITIONAL LEG MEANS HAVING PORTIONS DEFINING THE INNER SIDE OF THE TWO GAPS; (G) SAID RECORD MEMBER AND SAID MAGNETIC CIRCUIT MEANS COOPERATING WHEN A POLE ON THE RECORD MEMBER CROSSES A GAP TO REVERSE THE DIRECTION OF FLUX IN ONE ONLY OF SAID FIRST AND SECOND LEGS WHILE THE DIRECTION OF THE FLUX IN THE OTHER OF SAID FIRST AND SECOND LEGS REMAINS CONSTANT, WHEREBY A RESULTANT OF THE FLUXES IN THE FIRST AND SECOND LEGS; (1) HAS A PREDETERMINED VALUE WHEN A POLE ON THE RECORD MEMBER IS SPACED OUTWARDLY FROM SAID TWO GAPS IN EITHER DIRECTION, AND (2) HAS A VALUE SUBSTANTIALLY DIFFERENT FROM SAID PREDETERMINED VALUE WHEN THE POLE IS BETWEEN THE GAPS.
Claim 2
Dependent Claim
264 words
APPARATUS FOR SENSING A MAGNETIC RECORD, COMPRISING: (A) MAGNETIC READ HEAD MEANS; (B) A MAGNETIC RECORD MEMBER; (C) MEANS FOR RELATIVELY MOVING THE READ HEAD MEANS AND THE RECORD MEMBER; (D) SAID RECORD MEMBER CARRYING A MAGNETIC RECORD INCLUDING UNIDIRECTIONALLY MAGNETIZED POLES, EACH POLE BEING SPACED FROM THE NEXT ADJACENT POLE BY AT LEAST A PREDETERMINED DISTANCE IN THE DIRECTION OF SAID RELATIVE MOVEMENT; (E) SAID READ HEAD MEANS COMPRISING MAGNETIC CIRCUIT MEANS DEFINING TWO NON-MAGNETIC GAPS ADJACENT THE RECORD MEMBER, SAID GAPS BEING SPACED IN THE DIRECTION OF RELATIVE MOVEMENT BY A DISTANCE LESS THAN SAID PREDETERMINED DISTANCE, (F) SAID MAGNETIC CIRCUIT MEANS COMPRISING: (1) A FIRST LEG DEFINING THE OTHER SIDE OF THE GAP FIRST CROSSED BY A POLE ON THE RECORD MEMBER DURING SAID RELATIVE MOVEMENT; (2) A SECOND LEG DEFINING THE OUTER SIDE OF THE GAP LAST CROSSED BY THE RECORD MEMBER; (3) ADDITIONAL LEG MEANS HAVING PORTIONS DEFINING THE INNER SIDE OF THE TWO GAPS; (G) SAID RECORD MEMBER AND SAID MAGNETIC CIRCUIT MEANS COOPERATING WHEN A POLE ON THE RECORD MEMBER CROSSES A GAP TO REVERSE THE DIRECTION OF FLUX IN ONE ONLY OF SAID FIRST AND SECOND LEGS WHILE THE DIRECTION OF THE FLUX IN THE OTHER OF SAID FIRST AND SECOND LEGS REMAINS CONSTANT, WHEREBY A RESULTANT OF THE FLUXES IN THE FIRST AND SECOND LEGS; (1) HAS A PREDETERMINED VALUE WHEN A POLE ON THE RECORD MEMBER IS SPACED OUTWARDLY FROM SAID TWO GAPS IN EITHER DIRECTION, AND (2) HAS A VALUE SUBSTANTIALLY DIFFERENT FROM SAID PREDETERMINED VALUE WHEN THE POLE IS BETWEEN THE GAPS.
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) | 1969-03-07 | 1969-09-06 | 1970-03-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-03-07 | 1973-09-06 | 1974-03-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-03-07 | 1977-09-06 | 1978-03-08 | $7700.00 | Window Closed / Lapsed |