| 摘要 |
<p>The invention relates to a device for producing a drill hole in rock material, comprising a core drill bit (2) arranged on the drill string (1) and projecting from the diameter of the drill string (1) with its diameter. The drill string (1) is surrounded by a casing pipe (3) in at least the terminal zone behind the core drill bit (2), said casing pipe (3) being slotted at least across a part of its length. The device according to the invention is characterized in that for expanding the casing pipe (3), the slotted casing pipe (3) has an internal thread (5) at least across part of its slotted length and that a thread-guided mandrel (8) having an external thread (9) is provided between the internal thread (5) and the core drill bit (2) and can be engaged with the internal thread (5). Said thread-guided mandrel (8) can be retractably screwed into the internal thread (5) by means of the drill string (1) until its external thread (9) engages with the internal thread (5), preferably by means of a form-lock connection with the drill string (1), at least one of the threads (5 or 9) being conical.</p> |
