| 摘要 |
<p>The rotary drill bit is particularly for tunnelling, having a tool holder with a spindle. The tool holder body (3) is in the form of a cap fitting over the spindle (2) and capable of rotating on it, rings (4) being included between them to secure them together. An enlarged annular or cylindrical recess (5) can be formed inside the body, in which one retaining ring (4) on the spindle fits. The spindle can have a conical supporting head (6), against which faces on the body rest (7), with lubricant between. Pockets (8) for lubricant can be provided between head and body faces.</p> |
