| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to easily maintain a measurement element.SOLUTION: A target mounting/dismounting device comprises: a target unit 68 that is mounted on a leading propulsion pipe m1 by using predetermined magnetic force, includes a measurement element for measuring a guiding head 23's position, and has a first thread part formed at the rear end; an alignment device 74 for aligning the target unit 68 with the leading propulsion pipe m1; a monitor for displaying the guiding head 23's position; and a connection jig comprising a second thread part at the front end and a pulling-out rod at the rear end. In the case of maintaining the measurement element, connecting the target unit 68 with the connection jig inside a propulsion pipe train before pulling the pulling-out rod makes it possible to extract the target unit 68 to the outside of the propulsion pipe train. Inserting the target unit 68 after maintenance into the propulsion pipe train makes it possible to align the target unit with the leading propulsion pipe m1.SELECTED DRAWING: Figure 1 |
