| 摘要 |
PROBLEM TO BE SOLVED: To provide an excavator which can efficiently carry out excavation while preventing cave-in of a bored wall. SOLUTION: According to the structure of the excavator, a casing top 12 is attached to the tip of a casing pipe 11 in a manner being movable in a direction of an axial line O and rotatable about the same, and the casing top 12 has an extended cylinder portion 23 which is extended, on its tip side, to a perimeter of a skirt portion 15b of an excavating bit 15. Then, the excavator is comprised of a thrust/blow transmitting means 22 which is arranged in a gap between an inner peripheral portion of the casing top 12 and an outer peripheral portion of a device 14, for transmitting thrust and blow which have been transmitted to a rod 13 to the casing top 12, and moving the casing top 12 with respect to the casing pipe 11 in the direction of the axial line O. COPYRIGHT: (C)2003,JPO
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