Patent US3671346A successfully refreshed from Google Patents.
US3671346A
Expired / Lapsed
US
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Method of water sealing segments
Assignee: Individual
•
Filing: 1969-01-16
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Granted: 1972-06-20
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Expires: 1989-01-16
Abstract
Abstract A SYSTEM FOR SEALING JOINTS BETWEEN SEGMENTS ARRANGED BESIDE EACH OTHER TO LINE A CAVITY SUCH AS A TUNNEL. EACH SEGMENT HAS A GROOVED SIDE EDGE ABUTTING AN ADJOINING SEGMENT TO FORM A JOINT THEREWITH. A BITUMINOUS MATERIAL IS SITUATED WITHIN THE GROOVE AT THE JOINT AND AN ELECTRICAL CONDUCTOR IS ALSO SITUATED IN THE GROOVE, CURRENT BEING SUPPLIED TO THE CONDUCTOR FOR HEATING THE BITUMINOUS MATERIAL SO THAT IT WILL SPREAD AND FILL THE JOINT. THE SUPPLY OF ELECTRICAL CURRENT TO THE CONDUCTOR IS THEN TERMINATED SO THAT THE BITUMINOUS MATERIAL WILL HARDEN IN THE JOINT, PROVIDING AN EFFECTIVE WATER SEAL.
Inventors
- 👤 Yoshiro Tsuzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:57
CPC Classifications
E; E21; E21D; E21D11/00; E21D11/38; E21D11/385; E21D11/04; E21D11/08; E21D11/083
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |