Patent ID: 8069928
Filing Date: 2011-12-06
Classification: B25D,E21B,Y10T

Abstract:
1. A percussion device including, inside a machine housing, a reciprocally moveable percussive piston, the movement of which being controllable through a control valve, which is arranged to alternatively connect a chamber to a pressure source and to low pressure in dependence of a signal describing the axial position of the percussive piston, wherein inside said chamber a drive face on the percussive piston is received, wherein a plurality of axially separated control channels for transmitting said signal have openings in a cylinder space for the percussive piston in order to co-operate with a control edge on the percussive piston, and wherein valve means are provided to control the position of the control valve and are arranged to allow adjustment of in which axial position of the percussive piston said signal is transmitted, through respectively opening and blocking of connection between one or a plural of said control channels and the control valve, said valve means being disposed between each of said control channels and said control valve, wherein—said valve means includes a first valve element, which is controllable between a first position, wherein it is arranged to block a first portion or portions of a respective connection between a first subset of control channels and the control valve and a second position, wherein it is arranged to open said first portion or portions, and wherein said valve means also includes a second valve element which is controllable between a first position, wherein it is arranged to block a second portion or portions of a respective connection between a second subset of the control channels and the control valve and a second position, wherein it is arranged to open said second portion or portions, said first and second valve elements are arranged to be movable relative to each other.