| 摘要 |
PURPOSE:To correct the direction of path using a simple construction regardless of the diameter of an applicable buried pipe. CONSTITUTION:A movable correction blade port 3 can be inclined with respect to an outer pipe 2. Both the pipes 2, 3 are pushed by a buried pipe 1 having a diameter smaller than those of the pipes 2, 3. A correction head 4 having on its front surface protrusions 11, 12 having different height is provided in the pipe 2. An inner pipe 13 is connected to the rear end of the head 4. In a pushing operation, a thrust is imparted to the pipe 1. For correcting the direction of orbit, the pipe 13 is rotated to fix the circumferential position of the head 4 and the pipe 13 is pushed so that an offset force is imparted to the blade port 3 by the protrusions 11, 12. If the pipe 1 is pushed under this condition, reactive force of earth pressure is imparted to the port 3, so that the direction thereof is corrected. |
