| 摘要 |
PROBLEM TO BE SOLVED: To remarkably enhance efficiency of boring work by a simple improving technology of having only a cutter in a connecting coupler of a boring rod. SOLUTION: This connecting coupler 6 of the boring rod 4 has a boring bit 5 on the tip, and makes rotary motion and hammering motion, and has the cutter 8 on at least the boring directional tip side of a surface part of a coupler body 7 for cutting a root and a stem of a tree according to rotation of the coupler body 7.
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