Impact-action machine

An impact-action machine comprises a housing 1, a stationary cylinder 2 arranged in the housing 1, whose walls are arranged to form together with the housing 1 an intermediate space 3, while in the cylinder 2 is arranged a striking element 8 and a reciprocating driving piston 6, which are separated from each other by an air cushion 9, and holes 12 located in the side walls of the piston 6 for removal of air from the air cushion 9 and supply of air to it in order to equalise the pressure in the air cushion 9 in a zone at the upper or lower dead points of the piston 6, respectively, wherein according to the invention the wall of the stationary cylinder 2 immediately underneath the end surface 15 of the piston 6 in the zone at the upper dead point of the piston 6 is provided with a hole 14, arranged to connect the air cushion 9 to the intermediate space 3 between the stationary cylinder 2 and the housing 1. The cross section surface of the hole 14 is preferably 0.14-0.33 of the cross section surface of the hole in the piston 6.