Abstract: An arrangement for controlling a winch cable connected to rock drilling equipment, the arrangement including the winch; a pressure fluid motor arranged to operate the winch; a pressure fluid pump for operating the pressure fluid motor; a pressure-controlled pressure relief valve installed between a pair of pressure fluid channels connected to the pressure fluid motor for setting a counterpressure of the pressure fluid motor when pulling the cable off a drum; and control means for controlling counterpressure of the pump; wherein the pump is a pressure-controlled volume flow pump and the control means comprise an adjusting device with which a control pressure prevailing in a control channel of the pressure relief valve can be adjusted for setting a limit pressure of the pressure relief valve and thus the counterpressure of the pressure fluid motor.

Abstract: An arrangement for controlling the oscillation of a rock drilling equipment, comprising oscillation cylinders acting between a body and two crawlers, an oscillation selector valve allowing the oscillation cylinders to be interconnected. Locking valves are mounted in the oscillation cylinders, which valves prevent the flow of pressure fluid from the oscillation cylinders e.g., in the case of a hose damage, thus locking the crawlers and the body against movement relative to each other.

Abstract: A method and an arrangement for controlling the supply of air into a rock drilling machine. In the method, the air supply of an air compressor in a power unit operated by a diesel engine is adjusted so that when the percussion pressure of the percussion device of the rock drilling machine is high, the amount of air supplied by the compressor is small, and vice versa. In the arrangement, the pressure fluid pump of the hydraulic motor of the compressor is an adjustable-displacement pump, the volume flow of the pressure fluid supplied by the pump being adjusted inversely proportionally to the pressure of the supply conduit of the percussion device of the rock drilling machine.