FORETREDESVIS FOR BERGBORR AVSEDD VETSKEMOTOR

摘要

A percussive rock drill and more particularly a percussive rock drill having improved means for passing a flow of flushing fluid therethrough. The rock drill has a fluid motor including a body and a piston within the body. A fluid conveying tube extends within the body member and the piston, and a containment, including a pair of variable volume chambers connected by a passageway has in the passageway a passage portion extending within the pistons such that the heat transfer medium contained in the passage portion is maintained in heat exchange relation with the tube. The piston includes means effective to induce a flow of heat transfer medium within the passage portion during the movement of the piston by increasing the volume of one of the variable volume chambers while decreasing the volume of the other of the variable volume chambers.