Abstract: A method and an arrangement for drilling a hole in a rock (6), wherein a preliminary hole is drilled first, whereafter the drilling is interrupted. Joints between a drill boom (2) and a feeding beam (5) and/or the feeding beam (5) in its longitudinal direction are released so as to move freely in order that the boom (2) and the feeding beam (5) would take a substantially strainless position and the angles (.alpha., .beta.) of the joints and the position of the feeding beam (5) and the drill rod are measured. Thereafter the direction and distance from the preliminary hole (C) to the terminal point (B) of the originally designed hole is computed, and the drilling of the hole is completed.

Abstract: A bearing arrangement for a feeding device for a drilling machine, comprising a feeding beam (1) provided with longitudinal guides (6), a carriage supporting a drilling machine (3) and provided with guide surfaces in slidable engagement with the guides, and displacing means for displacement of the carriage along the guides. At least one guide surfce (5a) of the carriage is formed by a spacer (5) supported by the carriage. For automatical eliminatin of the clearance between the feeding beam and the carriage, the spacer is pressed against a wedging surface (8) provided on the carriage and extending essentially in parallel with the guide. The carriage is provided by means (9) for displacement of the spacer in between the guide surface (6a) of the guide of the feeding beam and the wedging surface (8) of the carriage so that the growth of clearance caused by wearing of the spacer is avoided as the wearing increases.

Abstract: A device for changing bore crowns on a drill rod including a bore crown magazine member and means for automatically stopping and locking the magazine member in a desired rotated position.

Abstract: A hydraulic drilling machine for cutting into rock formations and the like. The machine has a rotating drill rod with a bit at one end and a rotary hydraulic drive motor at the other end. The drill rod is supported on a carriage adapted for linear travel to advance the rotating bit into the rock formation. The carriage is extended and retracted by means of a hydraulic feed motor. The rotary hydraulic motor and the hydraulic feed motor are connected in series in the hydraulic operating system so that when rotation resistance increases accompanied by a greater pressure drop across the rotary hydraulic motor, there is a consequent decrease in the force exerted by the hydraulic feed motor in order to avoid jamming of the drill bit.

Abstract: A hydraulic drill, more particularly a rock drill, having a self-adaptive servo control system comprising three separate but interdependent hydraulic circuits, one for operating and controlling the drill rotation motor, one for controlling and operating the drill impact unit and a third for operating and controlling the drill feed motor.

Abstract: A hydraulic rock drill having a hydraulic drill drive motor, a hydraulic feed motor, and a hydraulic impact unit and associated pumps for supplying hydraulic fluid under pressure and provided with an automatic control system including a valve controlling the flow to the impact unit under the dependence of the pressure in the rotation motor circuit such as to reduce the power of the impact unit when the pressure in the drive motor circuit exceeds a permissible pressure and vice versa. Additionally, the hydraulic system preferably includes an additional flow control valve such as to decrease the feed power when the impact power increases.

Abstract: A lubrication system for rock drill machines powered by pressurized fluid, the lubricating system comprising a reservoir of lubricant, means for pressurizing the lubricant in the reservoir, conduits for feeding lubricant from the reservoir to individual dosage units, each connected to a particular lubrication point of the rock drill machine, the lubricant being supplied under pressure from the dosage unit by way of a rod- or plunger-operated piston reciprocable in the dosage unit, the end of the piston rod engaging an adjustable abutment, the dosage units being mounted such as to be reciprocable in unison with the rock drill by way of the drill feed unit.