US3821804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo system for positioning data transducer
Assignee: Individual
•
Filing: 1973-01-17
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Granted: 1974-06-28
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Expires: 1993-01-17
Abstract
Abstract A SERVO SYSTEM IS DISCLOSED FOR POSITIONING A MAGNETIC TRANSDUCER IN RELATION TO A PLURALITY OF TRACKS ON A DISC RECORD. A SERVO TRANSDUCER MOVES ACROSS A PLURALITY OF SERVO TRACKS IN SYNCHRONISM WITH MOVEMENT OF THE MAGNETIC TRANSDUCER. DISCRETE SIGNALS ARE RECORDED IN THE SERVO TRACKS IN SUCH A MANNER THAT MOVEMENT OF THE SERVO TRANSDUCER FROM ONE PAIR OF SERVO TRANCKS TO GENERATE TRACK CHANGE SIGNALS WHICH ARE DIFFERENT ACCORDING TO DIRECTION OF MOVEMENT OF THE TRANSDUCER.
Inventors
- 👤 T Stevenson
- 👤 R Yardy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B21/00; G11B21/02; G11B21/10; G11B21/106; G11B5/5552; G11B5/5556; G11B5/58; G11B5/596; G11B5/59688
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |