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 hand-operated pneumatic impact machine comprising a hollow body with an axially-reciprocating impact ram inside which forms, together with the body, variable-volume working chambers. It also comprises a distributing space communicating with the working chambers and with a source of compressed air. There also is a valve in the form of a cylindrical bushing whose inner surface covers at least one hole which admits compressed air into the distributing space, the compressed air forcing the valve to cover alternately the inlet channels of the working chambers for reciprocating the impact ram. The valve has at least one longitudinal channel which is in constant communication with the source of compressed air through a hole which connects the distributing space with the source of compressed air, the channel being intended to deliver compressed air to the inlet channels of the working chambers.

Abstract: An impact wrench comprises an anvil having impact jaws, a composite hammer including a driving part coupled to an output shaft of a pneumatic motor and a driven part having impact jaws for co-operating with the impact jaws of the anvil and mounted in the driving part for a combined rotation and a relative axial movement. A diametrical slot is provided in the driving part to receive a slider having its center of gravity offset relative to the hammer axis. The anvil receives a stub shaft mounted for a combined rotation together therewith and a relative axial movement and having a spring-loaded locking member co-operating with the slider. This construction of the pneumatic impact wrench enables a greater amount of kinetic energy to be transmitted into a threaded joint with each blow so as to improve the efficiency and reduce vibrations.