Abstract: A slide valve for a hydraulic percussion device. The slide valve includes a transition surface that is arranged to alternately be subjected to a working pressure and a tank pressure to carry out a reciprocating movement when the percussion device is in use. The slide valve includes at least one channel that is open at one end of the slide valve, and at least one displaceable pin that is arranged inside the at least one channel.

Abstract: A rock drill machine with a feed leg. The feed leg is attached to the rock drill machine with one end and rests on a support with another end. The feed leg is configured to feed the rock drill machine in a drilling direction and to interrupt feeding of the rock drill machine in the drilling direction. A control regulates the feed leg and a starter activates the rock drill machine. The control is provided on a rear handle in close proximity to the starter such that the control and the starter can be reached at the same time with one hand. Hereby, it is possible, with one hand, to activate and interrupt activation of the rock drill machine respectively, and simultaneously regulate the feed leg to feed the rock drill machine in the drilling direction and interrupt the feeding of the rock drill machine in the drilling direction.

Abstract: A method and an arrangement for controlling the feed of a rock drill. In the method, the pressure in a pressure conduit (7a) of a pressure-fluid-operated feed motor (6) is measured, and when the pressure value measured is below the pre-set threshold value, the volume flow of the pressure fluid delivered to the feed motor and thereby the feed rate of the feed motor (6) are adjusted, and when the pressure value measured is above the pre-set threshold value, the feed is adjusted by adjusting the pressure of the pressure fluid delivered to the feed motor (6). In the arrangement, a pressure detector (13) is arranged in the pressure conduit (7a) of the feed motor (6).

Abstract: The invention relates to a rock drill air leg control system incorporated in the backhead (10) of a rock drill. The system comprises a single spool valve (22) having two manual controls (46, 53), one for setting a trust applied by an air leg to a rock drill and the other for retracting the air leg without affecting the thrust setting achieved by operation of the first control. The first manual control is in the form of a twist-grip control (53) which is arranged to set the axial position of a spring-biased valve spool (30) in the valve (22) via a pin (50) and a plunger (46). The plunger (46) also forms the second of the manual controls and can be pressed against the spring-biased valve spool (30) to vary the axial position of this spool.

Abstract: A needle valve placed in series with the hydraulic drill feed motor, and responsive to fluid flow in the hydrualic system subject to the operation of a pressure relief valve therein, causes the thrust to increase and the feed rate to decrease as the drill enters a difficult drilling material, a proportional flow divider interposed between the pressurized hydraulic fluid source and the hydraulic drill rotation motor and the hydraulic feed motor splits the flow and maintains a fixed proportion between the flows to the two motors to cause the rotational motor to slow down as the feed motor slows down. A pressure compensated flow control valve bypassing the proportional flow divider to the drill rotation motor insures a fixed amount of fluid flow to the rotational motor regardless of the difficulty of material being drilled to maintain a minimal rotational speed of the drill rotation motor.