Abstract: The invention relates to a control valve, a percussion device and a method of controlling a working cycle of a percussion device. The percussion device (1) used for breaking rock comprises an impact element (8), which is controlled by a control valve (2). The control valve comprises a control element (5), which is arranged to control channels (7b) leading to a working pressure surface (9) of the impact element (8). The movement of the control element to its extreme position is arranged to form a closed pressure space, where pressure medium compresses and converts kinetic energy of the control element into pressure energy. The pressure energy is re-converted into kinetic energy and utilized when the control element changes its direction.

Abstract: The present invention relates to a valve control apparatus for operating a working piston, comprising a main valve spool including a smaller piston face subjected to compressed air from a reservoir and a larger piston face facing a main control space, further comprising an auxiliary valve spool having a first effective area which can be connected by a trigger valve to atmosphere or to a compressed air reservoir to displace the main control spool into an open position, and having a second effective area which is connected to a piston stroke chamber for displacing the main valve spool into a closed position, wherein the auxiliary valve spool is returned when the pressure acting on its second effective area falls below a predetermined value, wherein this effective area is connected to a shift valve which communicates with atmosphere when the trigger is not actuated and which is closed when being actuated and wherein the trigger is provided to move a first length of travel and a second length of travel to actuate