US3570145A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Teaching aid
Assignee: Individual
•
Filing: 1969-01-24
•
Granted: 1971-03-16
•
Expires: 1989-01-24
Abstract
Abstract A TEACHING AID INCLUDING A SLIDE VIEWER, HAVING TWO SLIDE TRACKS IN THE INTERIOR OF THE VIEWER THEREBY PERMITTING THE INSERTION OF TWO OVERLYING INDICIA BEARING SLIDES OR CARDS. CHARACTER OR WORD RECOGNITION IS TESTED AND PRACTICED BY HAVING A STUDENT INSERT A SECOND CARD, IDENTICAL TO A FIRST POSITIONED CARD SO THAT CONGRUITY IS EFFECTED. GATE MEANS IS MOUNTED IN EACH TRACK SO THAT THE CARDS ARE INSERTABLE IN ONE DIRECTION ONLY.
Inventors
- 👤 Joseph E Hickey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:51
CPC Classifications
G; G09; G09B; G09B17/00
Claims Analysis
Total Claims: 0
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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) | 1974-03-15 | 1974-09-14 | 1975-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-15 | 1978-09-14 | 1979-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-15 | 1982-09-14 | 1983-03-16 | $7700.00 | Window Closed / Lapsed |