US3401869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manhole ventilator
Assignee: Western Progress Inc
•
Filing: 1966-09-19
•
Granted: 1968-09-17
•
Expires: 1986-09-19
Abstract
No abstract record available.
Inventors
- 👤 Robert L Doyle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:50
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/40; F04D29/52; F04D29/522; F04D29/526; E; E03; E03F; E03F5/00; E03F5/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2394517A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-09-17 | 1972-03-18 | 1972-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-09-17 | 1976-03-18 | 1976-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-09-17 | 1980-03-18 | 1980-09-17 | $7700.00 | Window Closed / Lapsed |