US2989729A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Keyboard checking apparatus
Assignee: Unisys Corp
•
Filing: 1958-12-10
•
Granted: 1961-06-20
•
Expires: 1978-12-10
Abstract
No abstract record available.
Inventors
- 👤 Robert H Schafer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:00
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/22; G06F11/2205; G06F11/2221; H; H03; H03M; H03M11/00; H03M11/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2735091A
Cited
US2700755A
Cited
US2719959A
Cited
US2716230A
Cited
US2869076A
Cited
US2892153A
Cited
US2892888A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-06-19 | 1964-12-19 | 1965-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-06-19 | 1968-12-19 | 1969-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-06-19 | 1972-12-19 | 1973-06-20 | $7700.00 | Window Closed / Lapsed |