Patent ID: 7748327

Claim:
A moving device in a pipe line, comprising; more than three segments including a front segment arranged in serial; an extendable interconnecting means to connect adjacent segments; and an engaging force changing means to change an engaging force of the segment which is to be moved with an inside of the pipe line to a smaller force, smaller than the engaging force of the remaining segment with the inside of the pipe line; wherein the moving device moves back and forth by extending or retracting the extendable interconnecting means, wherein the front segment has a head part, a body part, a joint part to turn the head part centering around the body part, and a drive unit to move the head part around the body part, wherein the drive unit has a magnet provided in the head part and an electromagnet provided in the body part, and wherein the head part moves around the body part by attracting or repelling the magnet of the head part by the magnetic force of the electromagnet.