Abstract: An air-operated reversible percussive action machine comprises a housing in which there is disposed for axial reciprocations a hammer, defining therewith a front working chamber and having a through radial passage. In the axial interior of the hammer on the side of its tail end there is provided a cylindrical stepped tube including coaxially arranged first and second steps of large and small diameters, respectively, these steps having through radial passages. The first step of the tube defines with the hammer a rear working chamber, and with the second step defines an annular cavity in which a spring sleeve capable of axial displacements is disposed. The outer diameter of the sleeve is substantially less than the inner diameter of the first step of the tube to form an annular passage there between. The machine is further provided with a means for pressure-sealing the annular cavity and a means for controlling the displacements of the sleeve.

Abstract: A hollow housing has a piston hammer arranged for reciprocation therein. hammer has a rear end chamber, an air distributing valve secured in the rear end portion of the housing and adapted to be received by the rear end chamber of the piston hammer. A headpiece is secured to the forward end portion of the housing and subjected to impact of the piston hammer. A retainer embraces by at least one of its ends, the forward end portion of the housing and is disposed coaxially relative to the housing and the headpiece to ensure clamping of the forward end portion of the housing between the retainer and the headpiece.