| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground drilling machine enabling its structure to be reduced in size and weight extremely by adapting driving means with compact structure, and having no space, moreover, capable of giving a strong thrust to the movable base for driving the movable space. SOLUTION: The ground drilling machine comprises an impact driving shaft 5 in which a movable base 3 is movably supported on a guide cell 2 inclinably held on a base 1 along the longitudinal direction of the cell and the drilling rod 4 is connected to the movable base 3, and a hydraulic hammer 6 for hitting the output shaft 5 in the axial direction. Also, the ground drilling machine is provided with a toothed ring 15 in which a chain 16 or the like is fixed and installed along the guide cell 2 and which engages with the chain 16 or the like on the movable base 3, a driving motor 13 for driving the toothed ring 15, and a brake for applying braking force to the toothed ring 15.
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