Patent US3404392A successfully refreshed from Google Patents.
US3404392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic track following servo system
Assignee: International Business Machines Corp
•
Filing: 1967-04-14
•
Granted: 1968-10-01
•
Expires: 1987-04-14
Abstract
No abstract record available.
Inventors
- 👤 Frank J Sordello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:24
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/012; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B5/58; G11B5/596; G11B5/59633; G11B5/5965; G11B5/62; G11B5/64; G11B5/66; G11B5/672; G11B5/68; G11B5/70; G11B5/716; G11B5/74; G11B5/82; H; H01; H01F; H01F10/00; H01F10/06; H01F10/08; H01F10/10; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/925; Y10S428/9265; Y10S428/928; Y10S428/9335; Y10S428/934; Y10S428/935; Y10S428/936; Y10S428/937; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12639; Y10T428/12646; Y10T428/12736; Y10T428/1275; Y10T428/12986
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2643130A
Cited
US2647954A
Cited
US2714133A
Cited
US3185775A
Cited
US3052567A
Cited
US3263031A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-10-01 | 1972-04-01 | 1972-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-10-01 | 1976-04-01 | 1976-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-10-01 | 1980-04-01 | 1980-10-01 | $7700.00 | Window Closed / Lapsed |