Abstract: A pneumatic percussive tool has a barrel in which is inserted a hammer piston imparting blows at a working tool at regular intervals. A floating sleeve surrounding the working tool is provided in the front end portion of the barrel, the sleeve having a projection defining with a barrel groove a damping chamber communicating with a source of compressed gas. There is provided a shell rigidly secured to the barrel, which surrounds the sleeve so as to define in the zone of its projection an auxiliary damping chamber communicating with the source of compressed gas when the sleeve is in its lower position.

Abstract: A percussive tool has a working tool mounted for reciprocations in a barrel. A collar is arranged between a shank and a working portion of the working tool. The shank of the working tool reciprocates in a guide bushing secured in the barrel to ensure reciprocations of the working tool. There is provide4d a member for determining the angular position of the working tool during the reciprications, the member comprising either the barrel proper in case of concrete breakers, or a hood, e.g. in chipping hammers. For positively controlling the angular position of the working tool, there is provided a spring having two portions of different cross-sectional configuration, a first portion being coupled for a combined rotation to the member determining the angular position of trhe working tool, and a second portion being of a cross-sectional configuration corresponding to the cross-sectional configuration of the working portion of the working tool.