Abstract: A rotating device for rotating an apparatus arranged at the outer end of a boom, which boom has a longitudinal axis, the rotating device comprising a first torque motor unit arranged to rotate the apparatus substantially around an axis in the direction of the longitudinal axis of the boom, and a second torque motor unit arranged to rotate the apparatus around an axis that is at an angular position relative to the longitudinal axis of the boom, whereby the first and the second torque motor unit are arranged side by side relative to each other when seen in the direction of the longitudinal axis of the boom. The torque motor units are arranged in a body part common to both torque motor units.

Abstract: A telescopic feed beam for a rock drill includes a lower beam and an upper beam arranged to move with respect to each other in the longitudinal direction. The cross section of the lower beam is such that there is a groove-like open space at the bottom of the lower beam and a transfer cylinder between the lower beam and the upper beam is mounted in the groove.

Abstract: A telescopic feed beam for a rock drill, comprising a lower beam (1) and an upper beam (2) arranged to move with respect to each other in the longitudinal direction. The cross section of the lower beam (1) is such that there is a groove-like open space (1b) at the bottom of the lower beam and a transfer cylinder (5) between the lower beam (1) and the upper beam (2) is mounted in the groove.