| 摘要 |
<p>A method and an apparatus to steer and to observe the advancement of tubes (5) that have to be driven into the soil, in which method to the front of the first tube a soil cutting and essentially knifelike arm (1) is fastened, which extrudes from the ground and advances along with the tube head. By means of the arm contact is established from the ground to the tube head (4).</p> |
