US3559304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for teaching
Assignee: Individual
•
Filing: 1968-06-05
•
Granted: 1971-02-02
•
Expires: 1988-06-05
Abstract
Abstract AN INEXPENSIVE THROW-AWAY ANSWER SHEET OF OPAQUE MATERIAL ADAPTED TO BE DISPERSED OR PUNCTURED EASILY BY A HAND-HELD CONDUCTIVE STYLUS AND HAVING AN ELECTRICAL CONDUCTOR ON THE BACK OF THE SHEET EFFECTIVE TO BE ELECTRICALLY CONNECTED TO SAID STYLUS UPON THE PASSAGE OF SAID STYLUS THROUGH SAID SHEET, AND THE METHOD OF USING SAME TO CONSERVE MORE EXPENSIVE EDUCATIONAL FORMS.
Inventors
- 👤 Patrick A Kane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:23
CPC Classifications
G; G09; G09B; G09B7/00; G09B7/06; G09B7/063
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |