摘要 |
A device in rock drilling machines with a gripping device (24) which is rotatably mounted in a non-rotating drilling head (14) and intended to grip a drill string (21) for transferring rotational and axial movements to it. The gripping device is hydrostatically mounted (42, 43, 45-49) in the drilling head, whereby the pressure in a pressurized fluid between their coacting bearing surfaces (42, 43) automatically increases for increased loading pressure between these surfaces.
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