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US1576950A
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Safety shoe-tripping mechanism for doors
Assignee: National Pneumatic Co Inc
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Filing: 1921-04-11
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Granted: 1926-03-16
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Expires: 1941-04-11
Abstract
No abstract record available.
Inventors
- 👤 Conklin Roscoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:03
CPC Classifications
E; E05; E05F; E05F15/00; E05F15/40; E05F15/42; E05Y; E05Y2900/00; E05Y2900/50; E05Y2900/53; E05Y2900/531
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) | 1929-03-15 | 1929-09-14 | 1930-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1933-03-15 | 1933-09-14 | 1934-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1937-03-15 | 1937-09-14 | 1938-03-16 | $7700.00 | Window Closed / Lapsed |