US1840836A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanging apparatus
Assignee: SHAWPERKINS Manufacturing Co
•
Filing: 1929-06-17
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Granted: 1932-01-12
•
Expires: 1949-06-17
Abstract
No abstract record available.
Inventors
- 👤 Jr Archibald H Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:23
CPC Classifications
F; F28; F28D; F28D21/00; F28D21/0001; F28D21/0003; F28D21/0005; F28D21/0008; F28F; F28F9/00; F28F9/22; Y; Y10; Y10S; Y10S122/00; Y10S122/01
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) | 1935-01-11 | 1935-07-13 | 1936-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1939-01-11 | 1939-07-13 | 1940-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1943-01-11 | 1943-07-13 | 1944-01-12 | $7700.00 | Window Closed / Lapsed |