| 摘要 |
PURPOSE: To facilitate propelling of a small-diametered pipe by furnishing a pilot head, a target body in a direction correcting mechanism, a pilot pipe in whose hollow an infection pipe is laid, and a draining means. CONSTITUTION: When a different color light emitting body in the center of a target T is dislocated upward from the direct visible field due to transit, the pilot pipe is stopped rotating in the condition that the light emitting body arranged on the target surface is directed oppositely to the dislocation direction. If then the pilot pipe is propelled straight, the slope as the eccentric earth pressure receiving surface of the cutter part 6 of a pilot head 1 receives the earth pressure, and the pilot head 1 transfers in the direction of the central different color light emissing body on the side with the light emitting body of the target T, and excavation is made again in the position where the central different color light emitting body is discerned by the transit. In case water intrudes into the pilot pipe due to leakage at the time of water pouring and watching of the light emitting body is hindered by the transit, the water is taken from a through hole for drainage provided in the pilot head 1 by a forced draining machine D and discharged to the outside through a water injection pipe 12. |
