US3523657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microfilm viewing apparatus
Assignee: Indian Head Inc
•
Filing: 1967-09-15
•
Granted: 1970-08-11
•
Expires: 1987-09-15
Abstract
No abstract record available.
Inventors
- 👤 Guy H Hearon Jr
- 👤 Hans K Tannert
- 👤 Ronald W Randle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:35
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/10; G03B21/11; G03B21/111; G03B21/113; G03B21/14; G03B21/32; G03B21/43
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1041184A
Cited
US1969484A
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US2012437A
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US2197779A
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US2324453A
Cited
US2336278A
Cited
US2624231A
Cited
US3074311A
Cited
US3099397A
Cited
US3394899A
Cited
US3354776A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-08-10 | 1974-02-09 | 1974-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-08-10 | 1978-02-09 | 1978-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-08-10 | 1982-02-09 | 1982-08-11 | $7700.00 | Window Closed / Lapsed |