Patent US2649720A successfully refreshed from Google Patents.
US2649720A
Expired / Lapsed
US
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Drainage system for airports and highways
Assignee: Individual
•
Filing: 1947-03-04
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Granted: 1953-08-25
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Expires: 1967-03-04
Abstract
No abstract record available.
Inventors
- 👤 The Union Savings Trus Company
- 👤 Carl J Heltzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:30
CPC Classifications
E; E01; E01C; E01C11/00; E01C11/02; E01C11/22; E01C11/224; E01C11/227
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US494620A
Cited
US2148773A
Cited
US2254885A
Cited
CH146471A
Cited
GB351525A
Cited
US2072381A
Cited
US2319049A
Cited
US2330213A
Cited
US2280455A
Cited
US2342181A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-08-24 | 1957-02-23 | 1957-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-08-24 | 1961-02-23 | 1961-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-08-24 | 1965-02-23 | 1965-08-25 | $7700.00 | Window Closed / Lapsed |