Abstract: An impact wrench comprising a drive shaft, an anvil with impact cams, a striker having a flywheel mass connected to the drive shaft and impact cams connected to the flywheel mass so as to rotate therewith and move axially in relation thereto. The impact wrench includes a device designed for preventing the striker impact cams from interaction with the anvil impact cams until the striker attains a pre-set rotational speed. According to the invention, the flywheel mass and the anvil are immobile axially, whereas the striker impact cams are adapted to move axially in relation to the striker flywheel mass during striker acceleration.

Abstract: An impact wrench for tightening threaded joints by imparting a number of rotary blows to the threaded joint. The impact wrench comprises a housing which accommodates an impact clutch comprising an anvil and a hammer which consists of a driving member and a drive member, and a rotary drive of the hammer comprising an electric motor and a reduction gearing which has its output shaft mounted coaxially with the driving member of the hammer and is connected thereto for combined rotation only. The output shaft is connected to the driving member of the hammer by means of a spring-loaded pressure member accommodated in an axial bore of the output shaft and bodies of revolution contained in radial bores of the output shaft and engaging the spring-loaded pressure member. An annular groove is formed in the inner surface of the driving member of the hammer eccentrically relative thereto, and the bodies of revolution are received in the annular groove under the action of the spring-loaded pressure member.