Patent US3568329A successfully refreshed from Google Patents.
US3568329A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic fluid compass
Assignee: United States Department of the Navy
•
Filing: 1968-10-28
•
Granted: 1971-03-09
•
Expires: 1988-10-28
Abstract
Abstract A MAGNETIC COMPASS WHICH INCLUDES A BAR MAGNET, A FLUID COMPARTMENT WHICH ENCLOSES THE MAGNET, NEEDLE SUPPORT MEANS MOUNTED WITHIN THE COMPARTMENT SO AS TO SUPPORT THE MAGNET FOR ROTATION IN A HORIZONTAL PLANE, AND BUOYANT MATERIAL MOUNTED ON THE MAGNET FOR SUPPORTING THE MAGNET IN THE FLUID WITH A SLIGHT NEGATIVE BUOYANCY SO THAT FRICTION AT THE NEEDLE SUPPORT IS AT A MINIMUM, AND A SMALL SLAVE BAR MAGNET ROTATABLY MOUNTED TO THE COMPARTMENT AND IN AXIAL ALIGNMENT WITH THE LARGE BAR MAGNET SO AS TO FOLLOW THE MOVEMENTS OF THE LARGE BAR MAGNET.
Inventors
- 👤 Leslie T Cambell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:27
CPC Classifications
G; G01; G01C; G01C17/00
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |