Patent US2229404A successfully refreshed from Google Patents.
US2229404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permeability tuning
Assignee: Wells Gardner & Co
•
Filing: 1939-01-03
•
Granted: 1941-01-21
•
Expires: 1959-01-03
Abstract
No abstract record available.
Inventors
- 👤 Hartman B Canon
- 👤 Jesse H Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:37
CPC Classifications
H; H03; H03J; H03J3/00; H03J3/28; H03J3/30; H01; H01F; H01F21/00; H01F21/02; H01F21/06; H01F21/065
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) | 1944-01-21 | 1944-07-22 | 1945-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-01-21 | 1948-07-22 | 1949-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-01-21 | 1952-07-22 | 1953-01-21 | $7700.00 | Window Closed / Lapsed |