| 摘要 |
PROBLEM TO BE SOLVED: To provide an excavation tool provided with a widening bit rotatably fitted to the tool body by shaft hole fitting and recyclably made without disposing of the widening bit or the tool body even if abrasion arises in the shaft or the inner/outer peripheral part of the hole to improve the economical efficiency. SOLUTION: In the excavation tool in which a widening bit 4 rotatable around the center axis X deviated from the axial line O and positioned in the state that the outer diameter from the axial line O is widened, is attached to the outer periphery of the front end of the tool bodies 1, 7 rotated around the axial line O, the widening bit 4 is rotatably fitted to the tool bodies 1, 7 by fitting of the shaft 4B, 4C extending along the center axis X and holes 3G, 9D, and collars 10A, 10B are attached to at least one of the outer periphery of the shaft 4B and the inner periphery of the hole 9D. COPYRIGHT: (C)2004,JPO
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