US2420875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heating apparatus
Assignee: Heil Co
•
Filing: 1942-10-09
•
Granted: 1947-05-20
•
Expires: 1962-10-09
Abstract
No abstract record available.
Inventors
- 👤 Jr Herman C Frentzel
- 👤 Edward O Errath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:55
CPC Classifications
F; F24; F24H; F24H3/00; F24H3/02; F24H3/06; F24H3/065; F24H9/00; F24H9/0052
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2172667A
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US1440867A
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US516061A
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US2193735A
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US649502A
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US923404A
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US917756A
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US1363555A
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US1452249A
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US1641869A
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US1680166A
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US1692816A
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US1694392A
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US1688363A
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US1765439A
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US1862985A
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US2043387A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-05-19 | 1950-11-18 | 1951-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-05-19 | 1954-11-18 | 1955-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-05-19 | 1958-11-18 | 1959-05-20 | $7700.00 | Window Closed / Lapsed |