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 percussive action machine includes a housing in which a hammer is movably secured to define a forward stroke chamber and a return stroke chamber. The hammer is provided with an air-distributor fashioned as a sleeve having holes. The hammer is further provided with a device for alternately communicating the return stroke chamber with the forward stroke chamber and with the outside, the device having the form of at least one bore arranged inside the hammer in line with its axis. Communicating with this bore is a tubular control valve extending through the forward stroke chamber and having in its wall at least one hole wherethrough the return stroke chamber alternately communicates with the forward stroke chamber and with the outside.

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.

Abstract: Apparatus for building underground pipelines by forming a casing in a hole from a forming material which is compacted in the direction from the center of the hole towards its walls. The hole is first filled with the forming material throughout its cross-sectional area and then the material is compacted in the direction towards the walls of the hole. Compaction is effected by a device comprising a rod-shaped body adapted for moving through the hole, the front end of the body being provided with a system of radial ribs.

Abstract: A pneumatic impact mechanism for driving rod-like members having a hollow cylindrical casing with a tail portion and a front end portion. The casing accommodates a reciprocating stepped hammer piston defining in the casing, on the tail portion side, a variable volume rear end work chamber in permanent communication with a source of compressed air. The stepped hammer piston defines, on the side of the front end portion, a variable volume front end work chamber.The stepped hammer piston has a through-passing axial bore, and its small-diameter portion cooperates with the tail portion of the casing and has radial passages. There is provided a tubular guide member or element for receiving the rod-like member arranged coaxially with the stepped hammer piston and casing and secured to the tail portion and to the front end portion of the casing in such a manner as to cooperate with the stepped hammer piston and define therewith, with the outer periphery thereof an axial passage.

Abstract: The device comprises a hollow cylindrical body, pointed front at its end which device accommodates a striker forming the front working chamber in said body, and has a cylindrical space at its rear end. Said space receives an air-distributing and reversing mechanism, thus forming the rear working chamber. The air-distributing and reversing mechanism has a bushing which is fixed relative to the body, and an axially movable bushing, both bushings being arranged coaxially, spring-loaded in the axial direction relative to each other, and forming a chamber located in the front part of said mechanism, with the chamber communicating with a source of compressed air and intended to move the movable bushing during reversal of the device.

Abstract: A method of building underground pipelines by forming a casing in a hole from a forming material which is compacted in the direction from the center of the hole toward its walls. The hole is first filled with the forming material throughout its cross-sectional area and then the material is compacted in the direction towards the walls of the hole. Compaction is effected by a device comprising a rod-shaped body adapted for moving through the hole, the front end of the body being provided with a system of radial ribs.