US3500558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for the teaching of numeration systems to all bases
Assignee: BLAIR J MATEJCZYK
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Filing: 1967-12-08
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Granted: 1970-03-17
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Expires: 1987-12-08
Abstract
No abstract record available.
Inventors
- 👤 Blair J Matejczyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:13
CPC Classifications
G; G09; G09B; G09B23/00; G09B23/02; G09B19/00; G09B19/02
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) | 1973-03-16 | 1973-09-15 | 1974-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-03-16 | 1977-09-15 | 1978-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-03-16 | 1981-09-15 | 1982-03-17 | $7700.00 | Window Closed / Lapsed |