Abstract: A directional drilling tool which comprises a pair of shafts with an eccentric bore to vary the radial position of a stabilizer, such tool including one or more eccentric couplings which are used to transmit torque between a pair of elements of the tool which are intended to be movable relative to each other in a direction transverse to their longitudinal axes.

Abstract: A directional-control apparatus for a drilling tool, in which the direction of the drilling tool during the drilling of a borehole is controlled by means of at least one steering body which is moved radially against the wall of the borehole, the movement of the at least one steering body relative to the centre axis of the directional-control apparatus being adjustable in order to steer the drilling tool in a desired direction and at a desired deflection, and at least one electrically operated actuator being connected via at least one set of transmission elements to the at least one steering body and arranged to move the at least one steering body into a position relative to the centre axis of the directional-control apparatus, the relative position having the effect that the drilling tool is steered in the desired direction and at the desired deflection.

Abstract: A directional-control apparatus for a drilling tool, in which the direction of the drilling tool during the drilling of a borehole is controlled by means of at least one steering body which is moved radially against the wall of the borehole, the movement of the at least one steering body relative to the center axis of the directional-control apparatus being adjustable in order to steer the drilling tool in a desired direction and at a desired deflection, and at least one electrically operated actuator being connected via at least one set of transmission elements to the at least one steering body and arranged to move the at least one steering body into a position relative to the center axis of the directional-control apparatus, the relative position having the effect that the drilling tool is steered in the desired direction and at the desired deflection.

Abstract: A drill string section for directional drilling includes an outer casing which encases an adjustment mechanism for adjusting drilling direction and angular deflection during drilling. The adjustment mechanism has an outer shaft that is rotatably arranged relative to the outer casing and is configured with an axial eccentric first bore having a first bore axis that is parallel to the centre axis.