US2689947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable resonant frequency ultrasonic generator
Assignee: Individual
•
Filing: 1949-09-26
•
Granted: 1954-09-21
•
Expires: 1969-09-26
Abstract
No abstract record available.
Inventors
- 👤 William J Fry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:26
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-09-20 | 1958-03-22 | 1958-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-09-20 | 1962-03-22 | 1962-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-09-20 | 1966-03-22 | 1966-09-21 | $7700.00 | Window Closed / Lapsed |