Patent US2557566A successfully refreshed from Google Patents.
US2557566A
Expired / Lapsed
US
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Foundation ventilator
Assignee: Individual
•
Filing: 1947-04-19
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Granted: 1951-06-19
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Expires: 1967-04-19
Abstract
No abstract record available.
Inventors
- 👤 Howard W Ronfeldt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:38
CPC Classifications
E; E04; E04B; E04B1/00; E04B1/62; E04B1/70; E04B1/7069; E04B1/7076
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US347392A
Cited
FR743204A
Cited
GB191324671A
Cited
US1141417A
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US1720200A
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US1795001A
Cited
US1855294A
Cited
US2011797A
Cited
US2130811A
Cited
GB518399A
Cited
US2245931A
Cited
US2282946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-06-18 | 1954-12-18 | 1955-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-06-18 | 1958-12-18 | 1959-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-06-18 | 1962-12-18 | 1963-06-19 | $7700.00 | Window Closed / Lapsed |