US3649727A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Making concrete tubes
Assignee: Pfeiffer Maschinenfabrik Ettlingen Friedrich Pfeiffer KG
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Filing: 1969-03-11
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Granted: 1972-03-14
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Expires: 1989-03-11
Abstract
Abstract An apparatus for producing concrete tubes using a vertical tubular mold with a rotating piston moving upwards axially inside the mold. The piston is operated in such a manner that as the torque required for rotation of the piston decreases owing to a decrease in the supply of concrete, the rate of upward travel of the piston is decreased.
Inventors
- 👤 Friedhelm Gauger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:58
CPC Classifications
B; B28; B28B; B28B21/00; B28B21/02; B28B21/10; B28B21/22; B28B21/24
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |