US2209324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Duct heating system
Assignee: JOHN B PLERCE FOUNDATION
•
Filing: 1935-08-02
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Granted: 1940-07-30
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Expires: 1955-08-02
Abstract
No abstract record available.
Inventors
- 👤 Robert L Davison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:32
CPC Classifications
F; F24; F24B; F24B1/00; F24B1/18; F24B1/185; F24B1/188; F24B1/1885
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) | 1943-07-30 | 1944-01-29 | 1944-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-07-30 | 1948-01-29 | 1948-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-07-30 | 1952-01-29 | 1952-07-30 | $7700.00 | Window Closed / Lapsed |