Abstract: A hydro-mechanical device for underground drilling for use with a drilling rig comprises a container having a combustion chamber, an ignition system, inlets for introducing a fuel, an oxidizer, a liquid into the combustion chamber, a nozzle for discharging combustion products, a piston slidably mounted in the container and a reamer connected to the piston. The ignition system provides electro-discharges in the fuel, oxidizer, liquid mixture. Each electro-discharge has an explosive nature and produces combustion products having a high pressure. Combustion products are ejected through the circular nozzle surrounding the container to provide a thermal drilling action. The movable piston is pushed downwardly by the products of electro-discharge and causes the reamer to penetrate rocks or a frozen ground to provide a percussion drilling action. By the use of combined effect of thermo-percussion drilling, holes of significant depth can be drilled and rocks or frozen ground of high hardness can be pierced.

Abstract: The present invention comprises a rod pusher device which moves a drill string having a directional boring bit at its leading end. The invention includes a conversion device to automatically and simultaneously convert the axial movement of the drill string into a combined axial and rotational movement of the drill string. The conversion device is selectively engageable so that the push rod operator can readily select between axial movement of the drill string or combined axial and rotational movement, and thereby control the path of the borehole.

Abstract: In a self-propelled reversible boring ram, selection of forward/reverse boring modes is determined by the position of a control piston. A concentric supply pipe to a source of working fluid pressure connected to coaxial fluid inputs on the ram. Working fluid pressure for an impacting piston (hammer) is supplied through the input. For forward mode operation, pressure from a coil spring and reactive force on the piston is overcome by working fluid pressure on servo pistons. Restricting fluid pressure on the pistons allows the piston to move to reverse mode operating position.

Abstract: In an apparatus for creating an underground bore hole using high-pressure fluid within a steerable drill string to disturb and displace the subsoil, the improvement of the steering capability of the boring head by the inclusion of a percussive device to hammer the drill string forward after the desired steering of the boring head has take place to cause the boring head to fully engage the media being bored so that upon resumption of normal rotary drilling the boring head will proceed in the selected path.

Abstract: A percussion drill having a control device for controlling its travel forwards and/or backwards is provided with an adjusting and locking device for an axially movable control sleeve (4), this adjustment reversal device being adapted to be controllably operated with compressed air from a control station. A reliable reversal from forward to backward travel of the percussion drill is thus possible even in very long boreholes and even in the event of the collapse of the borehole.

Abstract: To manufacture a pile which is intended to take compressive as well as tensile loads or to serve as a reinforcement member in soils, a strip is wound off a roll of strip material and is carried through a rotating-roller shaping unit in which the strip is shaped by rollers. If desired, the unit is operated in such a manner that it forms a bend in the direction of pile advancement. A pile thus shaped is driven from the roller shaping unit by means of pressure in arbitrary directions into the mass of an earth layer. Upon attainment of the desired depth of penetration and/or pile length the pile is severed at or close to the upper surface of the earth layer.

Abstract: A placement and removal apparatus for use in insertion and withdrawal of a well point and the like includes a vertical support column and a gripping carriage that may be moved vertically along the support column. The gripping carriage includes a carriage frame with first upper and second lower clamp assemblies vertically spaced apart and disposed on the carriage frame. Each clamp assembly may be rotated independently about a common vertical axis of rotation. Opposed jaws associated with the clamp assemblies have a well point engaging surface and may be moved to engage about a surface of a well point disposed threbetween so that the gripping carriage may apply vertical and rotational forces to the well point.

Abstract: An apparatus has an eccentric shaft on which are mounted rolls connected to one another by flexible members in the form of a corrugated collar for end sealing of the rolls and with auxiliary members for radial sealing of the rolls. The auxiliary members are received in a radial clearance defined between the adjacent rolls which are made hollow.

Abstract: A self-propelled, pneumopercussive, cyclic action, ground penetrating machine (200) has decreased energy consumption and increased average working velocity compared to conventional machines. This is obtained in part by a valve-operated air-distribution mechanism (203) having separated forward and reverse compressed air supply lines (35, 37), which mechanism (203) does not limit the length of the forward and backward strokes of the striker (202). This mechanism allows the backward stroke chamber (75) to be connected with the atmosphere during the entire forward stroke of the striker (202). This eliminates generation of an air buffer in the backward stroke chamber (75) and, consequently, the striker (202) does not lose part of its kinetic energy before impact.

Abstract: A post driver for driving a wedged anchor into the ground wherein said wedged anchor is adapted to receive a post at the top end thereof comprising: an elongated inner shaft having a rectangular cross-section, said inner shaft having one end of which is adapted to be received by said wedged anchor; a plate co-extensive with said rectangular cross-section and fixedly secured at said one end of said elongated inner shaft; a hollow elongated outer shaft having spaced first and second open ends; said first open end of the hollow elongated outer shaft adapted to receive another end of the inner shaft for relative slidable movement therebetween; a mass presented at the second open end; aligned apertures presented by the mass and the outer shaft for receiving one end of a handle to retain the mass and the outer shaft together.

Abstract: The present invention provides a self-propelled impact boring tool which, according to one aspect of the invention, has a simplified tail assembly so that the tool can be readily assembled and dissambled to allow replacement of worn parts. Such a tail assembly includes a nut and an end cap which can be secured together by a series of conventional bolts which extend into threaded holes in the nut. The nut, which is screwed into the rear end of the tool body, can be clamped in position with the screws with far less torque than would otherwise be required with a conventional, unitary tailpiece.

Abstract: In a self-propelled ram boring machine, in particular for making earth bores, having a striking tool at the leading end of a cylindrical housing, a striking piston movable to subject said striking tool to ramming blows, said striking piston being driven with pulsating, translatory working strokes, the striking tool is mounted in the housing to rotate about the axis of rotation and comprises kinematic means cooperating with the housing to change a translatory movement following each blow of said striking piston into a gradual rotary movement, and pneumatically operable means for initiating or interrupting the rotary movement.

Abstract: A percussive-action mole 10 is energized by compressed air supplied through hollow rods 36 in a string 12 connected to the mole. A hydraulic motor 18 rotates the string and mole. The mole head 30 has a slant face 32 and a transverse permanent magnet 34. After each new rod is added to the string, the air is stopped to halt the mole which continues to be rotated. The field fluctuations from the magnet are detected by a magnetometer 24 using its probe at three positions 50, 52, 54 determiend by a triangular frame 22 placed flat on the ground. Calculations using the three readings each representing the distance of the magnet from the respective position on the frame enable the position and depth of the magnet to be determined. After completion, the passage 38 can be reamed to larger diameter to receive a gas pipe or other service.

Abstract: The disclosure describes an apparatus to use multiple expendable electromagnetically accelerated drill heads that are propelled into a electromagnetic accelerator that further accelerates the expendable drill heads to velocities as high as 30,000 ft./second to drill horizontal holes. Acceleration is achieved by making use of electromagnetic forces induced in a coil by opening a charged "ringing" circuit containing a capacitor interacting with magnetic poles around the expendable projectiles or drill head. Multiple accelerating coils, each charged by a D.C. source, are used while initial acceleration may be by interaction of electromagnetic fields between conductive rings on the drill head and induction coils.

Abstract: A ram boring machine for laying service lines in the ground without excavation, having a striking piston axially displaceable in a tubular housing and driven by means of a pressure medium via a supply hose connected to the housing, in which the supply hose is connected to the front end of the housing in the direction of advance and does not obstruct work on new pipes pushed into the passage made in the ground or drawn in simultaneously by the ram boring machine.

Abstract: The invention provides a steerable soil displacement hammer for driving holes in the ground. This comprises a substantially cylindrical body (1) and a soil displacement head (2) at a forward end of the body. The head is of larger diameter than the body so as to tend to create an enlarged hole around the body when the head is driven through the ground. At the rear end of the body a pivotable member is provided for directing said rear end away from the center of this hole.

Abstract: A manually operated downhole for an underground earth boring apparatus having a pneumatically operated earth boring tool. A drill pipe is connected to the tool and to a source of pneumatic fluid. A valve is positioned in the drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid. This downhole valve controls the flow of pneumatic fluid to the tool. The valve is operable in response to pushing or pulling on the drill pipe.

Abstract: A ram boring machine having a pull-and-turn reversing gear which comprises a striking piston axially displaceable in a tubular housing and a rotatably mounted control pipe with control openings such that forward and backward movement of the machine is controlled by moving the control openings over corresponding radial control openings in the striking piston, the control pipe having at least two parts with the rear part (viewed in the ramming direction) being connected to a supply hose, being relieved of the working pressure, and being connected to the bearing pipe by way of a force-loaded locking device which can be unlocked axially by traction on the supply hose against the loading force. This arrangement on the one hand prevents undesired reversal and on the other hand enables reversal to be effected under pressure.

Abstract: The present invention comprises a rod pusher device which moves a drill string having a directional boring bit at its leading end. The invention includes a conversion device, such as a RIGID link, mounted between a fixed point on the hydraulic thrust cylinder or frame assembly and the moveable drill string to automatically and simultaneously convert the axial movement of the thrust cylinder and drill string into a combined axial and rotational movement of the drill string. The link is removable so that the push rod operator can readily select between axial movement of the drill string or combined axial and rotational movement, and thereby control the path of the borehole.

Abstract: A pressure-medium driven ram boring machine for boring in the earth, having an impact tip acted on by a percussion piston reciprocating in the machine housing, wherein the impact tip is arranged to be radially adjustable in the housing whereby controlled directional changes of the machine can be effected.

Abstract: A manually operated downhole for an underground earth boring apparatus having a pneumatically operated earth boring tool. A drill pipe is connected to the tool and to a source of pneumatic fluid. A valve is positioned in the drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid. This downhole valve controls the flow of pneumatic fluid to the tool. The valve is operable in response to pushing or pulling on the drill pipe.

Abstract: An apparatus for screwing a concrete pile (10) into ground comprises a rotary drive (26, 40, 42) and a linear drive (46, 48) both acting on the pile. An angle indicator (58) is associated to the rotary drive (26, 40, 42) and a linear position indicator cooperates with the linear drive (46, 48). A control unit (60) receives the output signals of the angle indicator (58) and the linear position indicator (56) and provides control signals to the rotary drive (26, 40, 42) and the linear drive (42, 48) corresponding to the pitch of the helical rib (16) formed on the concrete pile (10).

Abstract: A percussive mole boring device with a location transmitter is disclosed. The transmitter is located in a forward end of a drilling assembly attached to a mole to accurately transmit the location of a boring element or cutting surface to surface detector. The transmitter is surrounded on each end by isolator means which protect the transmitter from damage due to shock created by the percussive device, e.g., a hammer driven by compressed air. In one embodiment the transmitter is located beneath a single window transparent to the transmission frequency, and the cutting surface of the bore is angled. Therefore, the travel direction of the mole can be controlled by rotating the cutting surface to a desired inclination and terminating rotation during forward motion for a short period. The mole travels in a straight path during ordinary travel due to rotation. In a second embodiment, the transmitter is located beneath three equiangularly displacent windows to create a continuous field for detection.

Abstract: A fluid-operated self-propelled subsoil penetrating tool of the type including an elongated housing member having a penetrating nose portion capable of ejecting a jet of liquid under high pressure to break up and disrupt the subsoil adjacent such nose portion followed by a two-component hammering of such soil to displace and compact same as the tool advances. Remotely-operated steering mechanisms control the path of the tool while remotely-read instruments denote the position, depth, direction and attitude of the tool. A trailing umbilical cord provides all motive and operational fluids and electrical power while transmitting instructions and data between the tool and the remote control station. A unique internal structure reduces the rotation of the tool as it advances and provides for the reverse movement of the tool and electrical supplies through the bore created by the movement of the tool through the subsoil.

Abstract: A ram boring implement having a pneumatically or hydraulically driven percussion piston, movable axially in a reciprocating manner in a housing, and an axially movable bit which is connected to an end of the housing and acted upon directly or indirectly by the percussion piston, is of a structure which permits a restoring piston, connected to the bit, to be acted upon by the pneumatic or hydraulic pressure during the return stroke of the percussion piston.

Abstract: In a rammer for driving in pipes open in the direction of ramming, in which a piston, axially reciprocated in a housing having an impact head, imparts its thrust to the housing, making the impact head integral with the housing allows a shorter rammer to be used without loss of thrust.

Abstract: A fluid-operated self-propelled subsoil penetrating tool of the type including an elongated housing member having a penetrating nose portion capable of ejecting a jet of liquid under high pressure to break up and disrupt the subsoil adjacent such nose portion followed by a two-component hammering of such soil to displace and compact same as the tool advances. Remotely-operated steering mechanisms control the path of the tool while remotely-read instruments denote the position, depth, direction and attitude of the tool. A trailing umbilical cord provides all motive and operational fluids and electrical power while transmitting instructions and data between the tool and the remote control station. A unique internal structure reduces the rotation of the tool as it advances and provides for the reverse movement of the tool and electrical supplies through the bore created by the movement of the tool through the subsoil.

Abstract: Long utility holes, for gas lines, electrical conduit, communications conduit and the like, may be bored or pierced horizontally through the earth, particularly under obstacles, such as buildings, streets, highways, rivers, lakes, etc. Such holes may be bored by an underground drilling mole (underground percussion drill) supported on a hollow drill rod and supplied with compressed air through the rod to operate an air hammer which strikes an anvil having an external boring face, preferably constructed to apply an asymmetric boring force. The drill rod is operated by a drill rig on the surface or recessed in special pit for horizontal drilling and provides for additional sections of pipe or hollow rod as the boring progresses. The asymmetric boring force causes the boring path to curve and, when straight line drilling is needed, the drill rod is rotated to counteract the asymmetric boring force.

Abstract: A locating device for a soil displacement hammer is disclosed and comprises a cylindrical, radio wave-transparent housing which is releasably connected between an air line for the soil displacement hammer (mole) and the hammer itself so as to permit air communication through the housing. Mounted along the axis of the housing is a cylindrical radio wave transmitter, such that, when the hammer is driven through the ground by repeated pneumatic impact, its location under the ground can be detected at the surface.

Abstract: A ram boring implement has a pneumatically driven percussion piston (16), which is movable in the axial direction in a reciprocating manner in a housing (12), and a control sleeve (24) which is axially adjustable for reversing the direction of motion of the ram boring implement and is acted upon by the pressure in one (20) of the pressure chambers (18, 20) formed on both sides of the percussion piston (16). The control sleeve (24) can be adjusted by means of a spindle drive (30, 50) by turning a compressed air supply hose (26). According to the invention, the control sleeve is arranged on a core (30, 34), supported in an axially fixed manner on the housing (12), so that the control sleeve itself forms only a relatively small annular effective area (52) acted upon by pressure. This makes it possible for the control sleeve to be moved forward or toward the rear without the compressed air feed having to be interrupted.

Abstract: An earth boring apparatus has a pneumatically operated earth boring tool, a flexible conduit or drill pipe connected to the tool and to a source of pneumatic fluid. The tool has an earth boring member and a reciprocally movable hammer positioned in the tool to apply a percussive force. A valve assembly in the flexible conduit or drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid controls the flow of pneumatic fluid to the tool. The valve assembly has a pneumatic pressure-operated valve which is operable in response to the pressure of pneumatic fluid in the flexible conduit or drill pipe to be opened to permit flow of pneumatic fluid to the tool at a predetermined operating pressure to transmit an initial pulse of pneumatic fluid to initiate operation of the hammer. The valve is kept open at a lower pressure than that required to open it.

Abstract: A reversible percussion device, having a casing 1 in which is installed a movable striker and a system for distributing fluid under pressure for causing the striker 4 to move for both forward and rearward movement functions of the device. The system comprises a control member 9 for controlling the distribution of fluid under pressure for both functions, which is movably coupled to the striker 4 and has a mechanism for locking it with respect to the casing 1 in two control positions, corresponding to the two functions of the device. According to the invention, the mechanism for locking the control member 9 in the position enabling the forward movement functions of the device comprises a body 11 movable relative to the control member 9.

Abstract: A finned impact-operated boring tool according to the invention has an elongated body with a frontally tapered nose which merged with a generally cylindrical housing. A circular array of fins project radially from the housing along the surface thereof rearwardly of the nose of the tool and near the juncture of the nose with the housing. Each fin is generally rectilinear, and the fins are spaced apart to define a series of grooves therebetween which extend in the lengthwise direction of the tool. The distance from the bottoms of these grooves to the lengthwise axis of the tool housing is greater than or equal to the distance from the tool axis to the outer surface of the housing. According to one embodiment of the invention, the fins are formed on a replaceable collar which fits over the node of the tool. The finned boring tool according to the invention has improved movement speed through the ground.

Abstract: A ground implanted support system includes a plurality of conical base members having irregular configurations in transverse cross section which are inserted in preformed complementary holes formed by a tool which is uniformly forced into the ground either manually or by controllable force producing means and thereafter each of the implanted base members receives a bolt, a plug, a post, or the like in a precast opening in the top of each base member. In a preferred form of the invention, the base members are precast from concrete and the base members are not inserted completely in the ground which reduces corrosion of the part being supported by the base members.

Abstract: An agitating and cutting blade structure of soil apparatus substantially comprises a plurality of concentric rotary shafts which rotate in mutually opposite directions and a plurality of agitating blades which are fixedly mounted on the respective rotary shafts and rotate in opposite directions corresponding to the rotation of the rotary shafts as well as a cutting blade fixed to the free end of one of the rotary shafts. Due to such construction, the soil receives a complicated and strong shearing force, is vigorously agitated and mixed with hardening agent efficiently hardened.

Abstract: The invention relates to the construction equipment. A device comprises a body (1) internally accommodating a percussion member (2) with ports (5), an air distributing sleeve (6), an elastic element (7) and a threaded bushing (8). Grooves (9) are made on an external surface of the threaded bushing (8) at an angle to the axis of the device. When the device is moving soil gets in the grooves (9) of the threaded bushing (8) and develops a circumferential force fixing the threaded bushing (8) relative to the body (1).

Abstract: An impact tool having an air-operated hammer for impacting against an anvil in the body of the tool to cause the tool to tunnel through the ground and having passages and conduits opening to the front tip of the tool to pass water to lubricate the tool to ease the passage of the tool through the soil during the propulsion of the tool, the front tip further having a headpiece through which the passages open to the tool exterior surface.

Abstract: An air-operated reversible percussive action machine comprises a housing (1) accommodating a reciprocating hammer (2). Secured inside the housing (1) is a stepped tube (5). The step of larger diameter of the tube (5) is received by a cavity (4) of the hammer (2) and has a port (12) for distributing air flow and feeding it to the interior of the housing (1). The tube (5) receives a sleeve (14) having a port (15) alternately communicable with the port (12) of the tube (5) in one of its two positions. One end face of the tube (5) has a projection (13) in the form of a sector of a circle, whereas the sleeve (14) is provided with a radial projection (16) so that in turning the sleeve (14) its projection (16) bears on one of the side walls of the projection (13) of the sleeve (5) thus assuming one of the two positions.

Abstract: A self-righting roadway marker support for a flexible boundary or roadway marker has a hollow anchor sleeve sunk into a supporting surface, a mounting collar secured to said anchor sleeve, a pivot strut extending through and upward from the collar, a compressible coil spring to resiliently urge the strut into contact with the collar, and a spring stop which selectively limits the extent to which the coil spring may be compressed. An oblong, radiused or chamfered aperture formed in the collar cooperates with a spring-mounting eyebolt to prevent the strut from rotating when deflected. A tool is also disclosed for installing the marker support. The force required to deflect the support assembly is set to be less than the force that would destroy or permanently set or deform the boundary marker.

Abstract: The invention is in an apparatus of self propelled type for forming an underground passage or space as the apparatus moves horizontally, vertically or in some other direction relative to the surface of the ground. The apparatus includes a head for reducing resistance of the soil through which it moves and for squeezing the soil in a desired direction as the head is caused to undergo multimode vibration. The apparatus also includes a thrust producing means for developing forward thrust and a connection for connecting the head and thrust producing means.

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 ground boring tool known as a mole is fitted within its conical head (1) with a pneumatic-powered rotatory vibrator (8) which generates severe radial vibrations. As a result the progress of the mole through resistant ground is speeded or made possible. The mole also may be used for upgrading existing ducts with or without the destruction of an existing lining to such ducts. For destruction of existing linings elongate ridges (16) may be positioned on the surface of the cone.

Abstract: A reversible percussive action machine includes a housing accommodating a mmer capable of reciprocating motions under the action of a working fluid under pressure, and a valving member with grooves movably connected to the hammer and provided with members for fixing it relative to the housing in two distribution control positions, particularly one that makes the machine move forward and one that ensures the return travel of the machine. The members for fixing the valving member in a position for the forward travel of the machine is fashioned as an insert movable relative to the valving member and having projections received by the grooves of the valving member. The insert is enclosed by a shell with ports, this shell being secured between the housing and the valving member to be capable of axial displacement.

Abstract: The technical field of the invention generally concerns groundline reinforcement of elongate objects such as a pole (20) and, in particular, a portable appartus (50) for installing an improved cylindrical split casing (30) around both the subterranean and above-ground portions of such an elongate object without cutting, moving, or otherwise disturbing it. The split casing (30) is assembled from two partial cylinders (32) having helical threads (34) formed at one end for engaging the ground (24) about the pole (20). Assembly of these two partial cylinders (32) about the pole (20) establishes a hollow annulus (44) between the pole (20) and the split casing (30). The apparatus (50) for installing the split casing (30) includes a split shell casing rotary drive (52) which is rigidly secured circumferentially about the assembled split casing (30). Also included in the apparatus (50) is a rotary driver (90) which mates with, engages, and is supported upon the split shell casing rotary drive (52).

Abstract: Long utility holes, for gas lines, electrical conduit, communications conduit and the like, may be bored or pierced horizontally through the earth, particularly under obstacles, such as buildings, streets, highways, rivers, lakes, etc. Such holes may be bored by an underground drilling mole (underground percussion drill) supported on a hollow drill rod and supplied with compressed air through the rod to operate an air hammer which strikes an anvil having an external boring face, preferably constructed to apply an asymmetric boring force. The drill rod is operated by a drill rig on the surface or recessed in special pit for horizontal drilling and provides for addition of sections of pipe or hollow rod as the boring progresses. The asymmetric boring force causes the boring path to curve and, when straight line drilling is needed, the drill rod is rotated to counteract the asymmetric boring force.

Abstract: Ground piercing attachment for a tractor comprising a bracket which is adapted to be mounted to the lower end of the bucket of a tractor, an elongated bar and connector means for mounting the bar on the bracket so that the longitudinal axis of the bar assumes a vertical position irrespective of the orientation of the tractor so that raising of the bucket enables the bottom end of the bar to be positioned above the ground and subsequent lowering of the bucket causes the bar to be driven into the ground.

Abstract: A reversible pneumatic underground piercing tool of the type having a reciprocating striker with the impact of the striker on the front or the rear of the tool being controlled by the longitudinal position of a valve element in the tool. An interengaging pin and slot arrangement in the tool defines the longitudinal the valve element which is positively maintained in the selected position by the supplied air pressure. The longitudinal position of the valve element may be changed for reversing the direction of movement of the tool by interrupting the compressed air supply and rotating the air supply hose a small amount in one direction or the other to reposition the pin in the slot.

Abstract: Apparatus for use in the laying and/or replacement of pipes under ground comprises a casing (1), a frusto-conical impact member (2) secured to one end of the casing and adapted to form an underground passage for the casing when the apparatus is being driven through the ground, a piston (7) reciprocally mounted in the casing and arranged to be driven by a source of compressed air or other fluid to engage the impact member (2) with a series of impacts to drive said member and the casing through the ground and a control valve member (11) adapted to be connected to a source of compressed air or other fluid and arranged to reciprocate the piston in the casing by means of said compressed air or other fluid. A pipe fitting (31) is connected to a tubular spacer member (23) which is mounted on the other end of the casing (1), said pipe fitting being adapted to be clamped to the leading end of a pipeline (29 and/or 30) which is to be laid in the underground passage formed by the impact member (2).

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 steering system is disclosed for percussion boring tools for boring in the earth at an angle or in a generally horizontal direction. The steering mechanism comprises a slanted-face nose member attached to the anvil of the tool to produce a turning force on the tool and movable tail fins incorporated into the trailing end of the tool which are adapted to be selectively positioned relative to the body of the tool to negate the turning force. The fins are constructed to assume a neutral position relative to the housing of the tool when the tool is allowed to turn and to assume a spin inducing position relative to the housing of the tool to cause it to rotate when the tool is to move in a straight direction. Turning force may also be imparted to the tool by an eccentric hammer which delivers an off-axis impact to the tool anvil. For straight boring, the tail fins are fixed to induce spin of the tool about its longitudinal axis to compensate for the turning effect of the slanted nose member or eccentric hammer.