| 摘要 |
<p>PURPOSE: To avoid the action of eccentric loads on pushing wheels and thrusting a pipe, by arranging a plurality of kinds of pipes with different diameters at the position where the extension of the axial line coincides with the axial line of the pushing wheel or closely approaches it. CONSTITUTION: A fixing member 58 is connected to a plate member 56 at the rear side of a pushing wheel 181 and thereafter, a hydraulic jack 44 is stretched and then the fixing member 58 is fitted to the rear face of the rear wheel 181 and the pushing wheel is further moved forward. By transferring the pushing wheel to the forefront position, a pipe 24 is thrusted from a shaft 12 wall into the ground. After thrusting a pipe 14, the pushing wheel 182 is manually transferred rearward until it bumps the fixing member 52 of the hydraulic jack 44 cylinder in an extended state. And after that, the fixing member 58 is fitted to both plate members 57 at the rear side of the cylinder 46 and then the fixing member 58 is fitted to the front face of the pushing wheel. Thereafter, the hydraulic jack 44 is contracted to return the pushing wheel to the initial position. A small diameter pipe 14 is held by both rails 16 with a narrow distance in a high level position with the level change of both rails and a large diameter pipe is held by both rails with a wide distance in a low level position.</p> |
