Abstract: The apparatus consists of a hollow body wherein there is contained a striker which divides the space inside the body into a forward operating chamber and a rear exit chamber. The striker is provided with ports for admitting compressed air into the forward operating chamber and for allowing the emission of spent air from the chamber. The striker is also provided with an interior space, the rear end face of said striker being left open. Said hollow body includes passages and a pipe for placing said interior space of said striker in communication with a source of compressed, the pipe being positioned for longitudinal travel relative to the body.

Abstract: A power tool having a cylindrical housing accomodating a hammer and a two-step defining piston head, with central, rear and supplementary chambers in the housing, said head and supplementary chambers being constantly intercommunicated through a passage provided in the housing. The design of the power tool is aimed at minimizing vibrations of the housing and reduction of the forces applied to the handle during normal operation of the power tool.

Abstract: A percussive device comprising a housing with a pointed front end and a hammer piston accommodated in the housing to form a front working chamber therewith. The hammer piston is provided, in the rear portion thereof, with a cavity in permanent communication with a source of compressed air, the cavity serving as a rear working chamber. An airdistribution mechanism includes a tube mounted in the housing within the hammer piston cavity so that it is conjugated with the walls of the cavity, the piston having air passages therein positioned in such a manner that, during the reciprocation, the tube alternately communicates the front working chamber, via these passages, with either the rear working chamber or ambient atmosphere.

Abstract: A percussive machine having an impact mechanism accommodated to a housing with a hammer piston imparting blows to a rock-destroying member. There is provided an air-supply duct for supplying compressed air to the impact mechanism and to the hole face. In order to prevent the machine from moving away from the hole face during the operation, the housing is provided with an elastic tubular member having a space in constant communication with the air supply duct.