DRILLING DEVICE WITH GUIDE ROD

PROBLEM TO BE SOLVED: To drill a continuous hole to the same depth as a preceding hole without forming an advancing/retreating drive source for the guide rod in a drilling device for drilling, with a drill rod, the continuous hole arranged continuously with the preceding hole in such a state that the drill rod 4 and the guide rod 5 are inserted into and supported on a centralizer 3, parallel to each other, at the front end of a guide cell 1 with the guide rod inserted into the drilled preceding hole H1 and the guide rod is inserted into the drilled preceding hole H1. SOLUTION: The rod holder 6 is fitted to the portion of the drill rod 4 projecting forward of the centralizer 3 rotatably relative to each other. The guide rod 5 is longitudinally slidably inserted into the rod holder 6 at the small diameter part 52 thereof extending from the large diameter part 51 at the front end rearward. A stopper part 53 restraining the sliding of the guide rod 5 forward of the rod holder 6 at the stroke end position where the front end of the guide rod 5 is positioned forward of the front end of the drill rod 4 is installed on the guide rod 5. COPYRIGHT: (C)2008,JPO&INPIT