US2524548A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Educational device
Assignee: Individual
•
Filing: 1949-07-11
•
Granted: 1950-10-03
•
Expires: 1969-07-11
Abstract
No abstract record available.
Inventors
- 👤 George W Speirs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:59
CPC Classifications
G; G09; G09B; G09B1/00; G09B1/02; G09B1/04; G09B1/06; G09B1/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
GB189818913A
Cited
US629527A
Cited
US632982A
Cited
US641739A
Cited
US1110434A
Cited
US1273763A
Cited
US1364778A
Cited
GB215168A
Cited
DE443726C
Cited
FR645949A
Cited
US2412180A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-10-02 | 1954-04-03 | 1954-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-10-02 | 1958-04-03 | 1958-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-10-02 | 1962-04-03 | 1962-10-03 | $7700.00 | Window Closed / Lapsed |