Patent US2673542A successfully refreshed from Google Patents.
US2673542A
Expired / Lapsed
US
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Method of making heat exchanger core tubes
Assignee: Individual
•
Filing: 1949-02-04
•
Granted: 1954-03-30
•
Expires: 1969-02-04
Abstract
No abstract record available.
Inventors
- 👤 Samuel H Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:17
CPC Classifications
B; B21; B21D; B21D53/00; B21D53/02; B21D53/04; B21D53/045; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49391; Y10T29/49805
Claims Analysis
Total Claims: 0
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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) | 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 |