Apparatus and technique for installing an elongated rod in an earth formation
US5067854A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 4, 1991 |
| Grant date | Nov 26, 1991 |
| Priority date | — |
| Expiry date | Feb 4, 2011 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/20
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A tubular casing 2 is installed in a tunnel 82 in the earth and the rod 14, 49 is advanced telescopically through the bore of the casing until a portion 49 of the rod is projected into the tunnel ahead of the casing, whereupon a pair of harpoon-like detents 138 anchor that portion of the rod to the wall of the tunnel so that the casing can be retracted in the opposite direction to remove it from around the remainder of the rod. When the distal end of the casing requires a cap 16 because the earth is unstable, pressurized fluid is applied to a piston-like insert 18 in the bore of the casing, to eject the cap and then the insert itself, before the rod is projected into the tunnel. Moreover, when the cap is equipped with a tunneling tool 74 and the casing is used to excavate its own tunnel, the fluid is ejected into the excavation through openings 120 and 80 in the insert and the cap, respectively, to assist the casing in excavating the tunnel; and when the casing is installed, the rod is used as a stopper 136 in the opening 120 of the insert, to plug it while the fluid ejects the insert. Then, the rod is projected into the tunnel ahead of the casing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.