PURPOSE: To smoothly drive and bury a new pipe by cutting open an existing buried pipe to expand the diameter thereof thereby advancing the new pipe through the buried pipe using small driving forces.
CONSTITUTION: A guide roller 24 is attached to a leading edge of small diameter 20a of a guiding pipe 20 and a breaking, cutting roller 25 is mounted to the tapered intermediate portion 20b of the pipe 20 and a diameter-expanding roller 26 is provided on the rear end portion of large diameter 20c of the pipe 20, whereby the guide roller 24 allows a new pipe 15 to smoothly pass through an existing buried pipe 4 and the buried pipe is cut open by the roller 25 so that the buried pipe is expanded radially outwardly of the new pipe 15 by means of the roller 26, thereby smoothly driving and burying the new pipe 15.
SHIMIZU YOSHIHIKO
KIKUCHI YUICHI
OKUBO KENJI
NOMURA NAOTA
AKAGI HIDEAKI
KOMATSU MFG CO LTD