US3021921A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ladder extension
Assignee: Individual
•
Filing: 1959-05-22
•
Granted: 1962-02-20
•
Expires: 1979-05-22
Abstract
No abstract record available.
Inventors
- 👤 Clement C Poelvoorde
- 👤 Stanley A Kapusta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:10
CPC Classifications
E; E06; E06C; E06C7/00; E06C7/42; E06C7/44
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1844760A
Cited
US1978865A
Cited
US2432245A
Cited
US2555036A
Cited
US2608794A
Cited
US2890824A
Cited
US2806723A
Cited
US2914135A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1965-02-19 | 1965-08-21 | 1966-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-02-19 | 1969-08-21 | 1970-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-02-19 | 1973-08-21 | 1974-02-20 | $7700.00 | Window Closed / Lapsed |