| 摘要 |
<p>An excavator for vertical bores is characterized in that it has a first head (24) which is provided at a lower end portion of a cylindrical body (12) with a cutter head (16) supported rotatably around the axis (14) thereof, and which has a vertically extending through hollow in the central portion thereof; at least one first cutter (26) provided on the first head so as to excavate the earth under the first head; a second head (28) which extends from the upper side into the through hollow detachably and coaxially, and which has a cylindrical portion (62) for receiving the earth excavated by the first cutter, and a bottom portion (66) for closing a lower end of this cylindrical portion; and at least one second cutter (30) provided on the second head so as to excavate the earth under the second head, the second head (28) further having at the bottom portion (66) thereof a bore for receiving in the cylindrical portion (62) the earth excavated by the second cutter (30).</p> |
