DRILLING BIT, ROTARY PERCUSSION DRILLING EQUIPMENT, AND METHOD FOR TESTING BOTTOM OF DRILLED HOLE

摘要

PROBLEM TO BE SOLVED: To perform a test and sampling without pulling out rotary percussion drilling equipment from a drilled hole.

SOLUTION: The center Os of a shank portion 19 of a drilling bit 1 held by a down-the-hole hammer 2 and the center Ob of a blade portion 21 at a drilling end are displaced from each other; a through-hole 12 penetrating to the blade portion 21 is provided in the central portion of the shank portion 19; the center of the blade portion 21 serves as the center of rotation; thus, the through-hole 12 is not clogged with soil; drilling can be performed by attaching the drilling bit 1 to a leading end of the down-the-hole hammer 2; and the test or sampling of the bottom of the drilled hole can be performed through the through-hole 12 of the drilling bit 1 after the completion of the drilling. Additionally, a tube rod 16, the center of which agrees with the center Ob of the blade portion 19, is elongated to the down-the-hole hammer 2; and the rotation is performed in such a manner that the center of the tube rod 16 serves as the center of the rotation, so that the existing down-the-hole hammer 2 can be utilized.

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