Improvements in retractile tunnel forms for poured concrete
US4261542A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 24, 1979 |
| Grant date | Apr 14, 1981 |
| Priority date | — |
| Expiry date | Jul 24, 1999 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE04G11/02
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
This invention relates to U-shaped tunnel-type forms for poured concrete having an upper horizontal panel resting on two spaced vertical sides which, in turn, are separated on the ground by a combination of jacks and wheels. The bottom portions of the two sides are connected by plural horizontal retractile tie beams. The upper horizontsl panel is supported by articulated horizontal beams pivotal at their ends and in the middle to permit the panel to be deformed by curving it downward, thereby pulling toward each other the spaced corners or edges of the dihedrons formed by the junctures of the spaced vertical sides and the horizontal panel. The improved form or coffering is characterized by the combination of plural articulated supporting beams for the horizontal panel supported by lengthwise adjustable inclined braces, axles having capacity for axial displacement relative to their wheels, but which are retractable automatically back to their median position by springs disposed on each side of the wheels, and lengthwise adjustable horizontal tie beams connecting the lower portions of the sides of the structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.