Patent ID: 8201640

Claim:
A method for controlling a fluid operated percussion device, which inside an axially extending cylinder room of a housing of the percussion device includes a to and fro moveable percussive piston, which is adapted for performing strikes in a striking direction and which includes a signal portion for controlling a main valve, which is adapted to intermittently transmit pressure fluid to at least one driving chamber for the percussive piston, whereby in the region of a first, rear end position of the percussive piston, the signal portion establishes a fluid conduit contact for setting the main valve for driving the percussive piston in the striking direction, and whereby in the region of a second, forward end position of the percussive piston, the signal portion establishes a fluid conduit contact for setting the main valve for driving the percussive piston opposite to the striking direction, wherein an auxiliary valve is controlled for transmitting fluid contact from a first auxiliary channel means, the first auxiliary channel means having a channel opening in the cylinder room, to the main valve by having the fluid pass through said channel opening of the first auxiliary channel means and the signal portion, so as to switch the main valve before the percussive piston, in operation, has reached the region of the first, rear end position of the percussive piston, and thereby before the signal portion has established said fluid conduit contact for setting the main valve for driving the percussive piston in the striking direction.