| 摘要 |
<p>By the process, the tubing (1) and inner-lying penetrating worm (2) are sunk simultaneously. When the device is pulled out during concreting, the entrance and exit hole of worm in the earth can be opened or enclosed in the tube for the earth that is being removed. At the bottom of the worm is a sealing device (3) which can lock the worm in the tube or release it. A drive element (4) governs the movement of the sealing device relative to the worm. The relative movement of the sealing device can be achieved independently of the turning direction of the worm. The operation and control of the drive element can be done from the surface. The drive element is designed so that independently of the turning direction of the worm and against the forces working on the worm, it keeps the openings of the worm open or shut.</p> |
