Patent US5132390A successfully refreshed from Google Patents.
Patent US2673920A successfully refreshed from Google Patents.
US2673920A
Expired / Lapsed
US
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Electric heater for water or the like
Assignee: HEAT X CHANGER CO Inc
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Filing: 1950-07-20
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Granted: 1954-03-30
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Expires: 1970-07-20
Abstract
No abstract record available.
Inventors
- 👤 William J Donovan
- 👤 Boling Cecil
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:56
CPC Classifications
A; A47; A47J; A47J31/00; A47J31/44; A47J31/54; A47J31/542
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
FR512798A
Cited
US1698596A
Cited
GB364664A
Cited
US2048104A
Cited
US2023373A
Cited
US2097581A
Cited
US2145287A
Cited
US2247816A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-03-29 | 1957-09-28 | 1958-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-03-29 | 1961-09-28 | 1962-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-03-29 | 1965-09-28 | 1966-03-30 | $7700.00 | Window Closed / Lapsed |