| 摘要 |
<p>A device in rock drilling machines with a gripping device which is rotatably mounted in a non-rotating drilling head and intended to grip a drill string for transferring rotational and axial movements to it. The gripping device it hydrostatically mounted in the drillin head, whereby the pressure in a pressurized fluid between their coacting bearing surfaces automatically increases for increased loading pressure between these surfaces.</p> |
