Abstract: A reversible air-operated percussive action machine for driving holes in the ground has a housing accommodating a hammer 2 capable of reciprocating therein. An air distributor 3 is arranged in the hammer 2 in the form of a fixed tube 12 and a valving member 13 movable relative to the tube. Defined between the tube 12 and valviong member 13 is an accumulating chamber 18 which communicates with an air feeding line 4. An air restrictor is further provided for discharging air from the accumulating chamber 18 when the supply of compressed air to the air feeding line is terminated. The valving member 13 spring-loaded relative to the tube 12 by a spring arranged so that during feeding compressed air to the accumulating chamber 18 the valving member 13 is acted upon by a pressure force directed counter to the action of the spring.

Abstract: A rock-breaking implement, preferably for a self-propelled percussive machine for driving boreholes, having a body, at least a part of the body facing the borehole faces being cylindrical in shape. The body is provided with rock-breaking wedges which are arranged in such a manner that their blades extend radially at the end face of the body. The body has grooves opening outside to the periphery of the body and designed to remove broken rock, the grooves extending along helical lines and intersecting one another so that portions of the body located between the intersecting grooves define the rock-breaking wedges. Edges of said wedges which extend on the periphery of the body within the cylindrical part thereof define a continuous circle when projected to the plane of transverse section of the body and are designed for forming the walls of the borehole.

Abstract: A rock-breaking tool for preferable use in self-propelled percussive machines for boring wells, comprising a casing with a pointed portion and an end face. The casing has an annular cutting edge formed by the pointed portion and inner tapered surface thereof. The casing is formed with a cone-shaped chamber open at the end face thereof, oriented toward the bottom of a well being drilled, the internal surface of the chamber intersecting with the conical surface of the annular cutting edge. The casing is also provided with ducts communicating the chamber with the surrounding space.

Abstract: A percussive device operable in a forward mode for making a hole in soil and operable in a reverse mode to retract the device from the hole. The device is provided with control means that change the mode of operation alternatively under control of a valve that turns air pressure on and off in a supply or feed line to the device. When the air is turned off from the device the valve establishes connection to an aspirator for establishing a suction condition to the device that will reverse the mode so that upon turning on of air back to the device will make it operate in the changed-over mode.

Abstract: The drill has a housing receiving therein a reciprocating striker, effecting percussive action upon the tool for breaking the rock at the face of the hole, mounted at the forward part of the housing, and upon the housing itself for propelling the drill in the hole. The housing also receives therein a mechanism for rotating the tool, including a self-controlled coupling provided with a movable sleeve and a stationary sleeve and adapted to transmit a torque to the tool in only one direction of rotation. The drill is provided with a device preventing a rearward motion of the housing and its rotation during a drilling operation. The drill is characterized by having a return device for retracting the tool from the face after it has been struck by the striker.