US3444579A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reversible,disposable chalkboard eraser pad and holder therefor
Assignee: Conwed Corp
•
Filing: 1967-05-17
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Granted: 1969-05-20
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Expires: 1987-05-17
Abstract
No abstract record available.
Inventors
- 👤 William F Thomford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:42
CPC Classifications
B; B43; B43L; B43L21/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-05-19 | 1972-11-18 | 1973-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-05-19 | 1976-11-18 | 1977-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-05-19 | 1980-11-18 | 1981-05-20 | $7700.00 | Window Closed / Lapsed |