Patent US3521429A successfully refreshed from Google Patents.
US3521429A
Expired / Lapsed
US
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Muffler
Assignee: FRANK B LEFFLER
•
Filing: 1968-10-04
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Granted: 1970-07-21
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Expires: 1988-10-04
Abstract
No abstract record available.
Inventors
- 👤 Frank B Leffler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:04
CPC Classifications
F; F01; F01N; F01N13/00; F01N13/18; F01N13/1805; F01N3/00; F01N3/02; F01N3/021; F01N3/022; F01N3/0222; F01N3/0226; F01N3/08; F01N2230/00; F01N2230/02; F01N2330/00; F01N2330/10; F01N2330/101; F01N2330/102; F01N2370/00; F01N2370/22; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1807521A
Cited
US1575657A
Cited
US1829401A
Cited
US2499018A
Cited
US3066462A
Cited
US3147097A
Cited
US3181646A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |