POSITION MEASURING INSTRUMENT FOR SMALL-BORE PIPE PROPELLING MACHINE

摘要

PROBLEM TO BE SOLVED: To reduce the longitudinal length of a launching vertical shaft and enhance the safety of measuring works. SOLUTION: A laser theodolite 20 is installed outside a launching vertical shaft 10, a prism mount 50 is disposed in the rear space of a propelling machine 20 in the vertical shaft 10, and a prism unit 40 is supported on the prism mount 50 to refract a laser beam from the laser theodolite 20, thereby guiding it to a target in the leading pipe 21 of the propelling machine 20.