Abstract: 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.

Abstract: A device in rock or earth drilling apparatus for rotary drilling including an axially stationary chuck (21) and an axially movable chuck (27) which is rotated by a reversible pressure fluid driven rotary motor (32) having a pressure fluid supply conduit for each direction and which is moved forwards and backwards by a reversible pressure fluid driven feed motor (17) having a pressure fluid supply conduit (18, 19) for each direction, the chucks being actuated to withdraw from or insert in a drill hole a drill string (23) composed by a number of threaded string elements and (are also actuated) to make or break the joints between the string elements.

Abstract: A device for reciprocating motion of a rotating drilling body of a drilling machine in the longitudinal direction of a hole drilled in rock or ground includes two cylinder-piston devices which via chains are connected to a carriage carrying the drilling body and which comprise parallel piston rods, the ends of which are supported by a frame on the machine, and cylinders movable along the piston rods and connected to each other and via the chains also to the carriage. To increase the feeding velocity of the carriage or to increase the force of the carriage one of the cylinders or both cylinders, respectively, are selectively fluid pressurized.

Abstract: A device in core drilling for indicating when a core barrel placed in a rotatable hollow drill rod is no longer capable of receiving a further quantity of reamed-out core material includes a valve which at said condition of the barrel constricts the passage for flushing medium flowing between the core barrel and the bore of the drill rod so that a readable flushing medium pressure increase occurs. The valve closes off said passage incompletely to allow a minor quantity of flushing medium to be taken to the drill bit mounted at the bottom of the drill rod, thereby to prevent said drill bit from being burnt out.

Abstract: A device for disengaging a grappling device from a core barrel, which are lowered in an engaged or connected state into a hollow drill rod, is actuated by a recess made in the drill rod bore, when the barrel approaches or assumes a working position in the drill rod, and is thereby displaced by a spring for disengaging the mechanism connecting the grappling device and barrel.