Abstract: An apparatus for replacing an existing pipe. The apparatus comprises a slitter and expander which surround a wire rope. The wire rope is attached to the expander, and the expander abuts either the slitter or a separation tube disposed between the expander and slitter, such that the slitter and expander are pivotable relative to each other. The apparatus is placed in a pipe to be replaced and pulled. While being pulled, blades on the slitter slit the pipe, while a sloped surface of the expander moves the slit sections apart into surrounding soil. A replacement pipe may be pulled by a pipe putter attached to the expander. A beacon may also be disposed within the apparatus to emit a signal for locating the apparatus white underground.

Abstract: A pipe expander assembly for replacing an existing pipe with a new pipe. The expander assembly has a slitter disposed about a wire rope and abutting an expander at a spherical joint. The expander comprises a cone to expand a slit pipe and is internally connected to the wire rope by jaws that expand and contract about the wire rope due to threading of a jam nut into the cone. A pipe puller is connected to the back of the expander at a clevis and is adapted for connection to a new pipe, either through a jaw system, an adaptor, or fusion to the pipe.

Abstract: An electronic transmitter assembly used in directional boring, the housing of the assembly being configured for receiving a beacon. The housing and cover of the assembly are configured to provide transmission windows along each side of the cover rather than in the center of the cover. The beacon contained within the housing is configured to have a forward isolator on one end and a rear isolator on the other end to isolate the beacon from shock during boring operations.

Abstract: A ground piercing tool as according to the invention has a front head assembly mounted on a bit shaft. A mid-portion of the bit shaft is mounted between front and rear chambers. Compressed fluid is supplied to the front chamber to form a gas spring that prevents the bit shaft from impacting against a front stop when it receives a blow from the striker. A valve is provided that includes a passage that permits communication between the front chamber and the rear chamber when the bit shaft is in a forwardmost position wherein it contacts the front stop. The valve permits compressed air to pass from the front chamber to the rear chamber, negating the gas spring when the bit shaft is in the forwardmost position.

Abstract: A roller cone drill bit having detachable rotatable arms. The arms are connected at a mounting pad to the bit body. Each arm has its own grease delivery system to provide lubrication to the interface between the arms and rolling elements at an end of each arm. The forward-facing contact surface between the bit body and the arms is at an angle, relative to the central axis of the bit, that is ninety degrees or more.

Abstract: A check valve for a drill string fluid delivery system. The fluid delivery system allows for drilling mud to travel from a source up the drill string, through the drill string, through a downhole tool assembly, to a port located at a surface of a boring tool. The check valve rests in a socket within the downhole tool assembly, with a forward face extending into a gallery within the bit. When the ambient pressure within the fluid delivery system exceeds the ambient pressure in the borehole, mud flows through the system to the ports and into the borehole. When the ambient pressure within the borehole exceeds the ambient pressure in the fluid delivery system, the pressure is applied to the forward face, causing the check valve to close, preventing contaminants from the borehole from entering the fluid delivery system.

Abstract: A system for pushing and pulling rod strings through the ground or an underground pipe. The apparatus has a downhole tool attached to the distal end of the rod string. The push/pull machine has a stationary frame that is placed against the ground to provide a reaction surface. The stationary frame has an opening for the rod string to pass through. A rod gripping assembly is supported on the machine frame and moveable relative to the stationary frame. The rod gripping assembly has a slip bowl, jaws, a thrust member and an actuator. The actuator powers movement of the jaws into the slop bowl to cause a powered gripping of the rod string by the machine. With the rod string gripped a cylinder assembly is activated to push the rod gripping assembly toward the stationary frame thereby pushing the rod string into the ground.

Abstract: A make-up/break-out device for use with a hammer used in horizontal directional drilling operations. The hammer comprises a drill bit assembly and a housing that are connected via low helix angle threads. The make-up/break-out device is used with the hammer to tighten or loosen the connection between the drill bit assembly and the housing. The make-up/break-out device comprises a vise arm, a lever arm, and drive arm.

Abstract: A reversible, pneumatic ground piercing tool has a tail assembly with exhaust passages therethrough. At least a portion of each exhaust passage angles radially inwardly and ends in discharge ports that communicate with a central hole at the rear end of the tail assembly, whereby exhaust escapes through the central hole. A tail cone has a radially inwardly extending flange on the inner periphery of the central hole, which flange is rearwardly spaced from and covers the discharge ports.

Abstract: A ground piercing tool as according to the invention has a front head assembly mounted on a bit shaft. A mid-portion of the bit shaft is mounted between front and rear chambers. Compressed fluid is supplied to the front chamber to form a gas spring that prevents the bit shaft from impacting against a front stop when it receives a blow from the striker. A valve is provided that includes a passage that permits communication between the front chamber and the rear chamber when the bit shaft is in a forwardmost position wherein it contacts the front stop. The valve permits compressed air to pass from the front chamber to the rear chamber, negating the gas spring when the bit shaft is in the forwardmost position.

Abstract: A reversible, pneumatic ground piercing tool has a tail assembly with exhaust passages therethrough. At least a portion of each exhaust passage angles radially inwardly and ends in discharge ports that communicate with a central hole at the rear end of the tail assembly, whereby exhaust escapes through the central hole. A tail cone has a radially inwardly extending flange on the inner periphery of the central hole, which flange is rearwardly spaced from and covers the discharge ports.

Abstract: An impactor for use with a directional boring machine for replacement of underground pipes includes a bursting head having a rearwardly opening recess and a front end opening that communicates with the recess. An inlet pipe is connected at its front end to a distal end of the drill string and extends into the recess of the bursting head through the front end opening. A striker is mounted for sliding movement along the inlet pipe, and a distributing mechanism responsive to pressure fluid supplied through the drill string and inlet pipe causes the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the bursting head. The striker and distributing mechanism are mounted in a tubular housing, and a pulling connection is provided by which the impactor can be pulled by the drill string while the striker is delivering impacts against the head in the same direction as a pulling force exerted by the drill string.

Abstract: A method for installation of an underground pipe includes an initial step of boring a pilot hole through the ground at a predetermined grade angle by extending a drill string having a steerable boring bit mounted thereon through the ground. Upon reaching an end location for the pilot hole, the bit is removed from the drill string, and an expander having a diameter greater than the pilot hole is attached to the drill string, which expander is backed by an impact device such as a pneumatic impactor including a striker that delivers repeated impacts to a rearwardly facing surface of the expander, and by a pipe drawn along behind the expander. The expander is pulled back through the pilot hole at the grade angle while the impactor is operated to aid progress of the expander through the ground and pull the pipe into place behind the expander.

Abstract: A ground piecing tool includes a housing and an air distributing mechanism that reciprocates a striker to impact a chisel shaft in response to a supply of compressed fluid including a fluid inlet tube mounted in the bore of the striker having a radial port, a rear end of the inlet tube being in communication with the distributing mechanism, wherein the housing and chisel shaft cooperate to define a front chamber that decreases in volume as the chisel moves forward relative to the housing, and wherein the chisel shaft has a radial passage therein that conducts compressed fluid from the radial port of the inlet tube to the front chamber, which is configured to form an air spring.

Abstract: An impactor for use with a directional boring machine for replacement of underground pipes includes a bursting head having a rearwardly opening recess and a front end opening that communicates with the recess. An inlet pipe is connected at its front end to a distal end of the drill string and extends into the recess of the bursting head through the front end opening. A striker is mounted for sliding movement along the inlet pipe, and a distributing mechanism responsive to pressure fluid supplied through the drill string and inlet pipe causes the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the bursting head. The striker and distributing mechanism are mounted in a tubular housing, and a pulling connection is provided by which the impactor can be pulled by the drill string while the striker is delivering impacts against the head in the same direction as a pulling force exerted by the drill string.

Abstract: A pneumatic ground piercing tool includes a tail assembly including a tail nut and tail cap, the tail cap having a plurality of discharge ports for exhausting spent compressed air, the discharge ports opening into an annular space between a rearwardly opening recess of the tail cap and an air supply conduit such that the exhaust ports are shielded by a side wall of end cap from plugging when the ground piecing tool is operated in reverse mode.

Abstract: A method of the invention uses a pneumatic ground piercing tool having a reversing mechanism with a supplemental air line capable of supplying compressed air for reverse operation to a radial port in the air distributing mechanism. This radial port is located between a pair of bearing surfaces on the step of the air inlet conduit, and when pressurized by the supplemental air line, causes the front pressure chamber to receive compressed air earlier than normal, shifting the stroke of the striker rearwardly so that the tool operates in reverse. Such a method includes the steps of operating the tool in forward mode by supplying compressed air to the first air hose, and operating the tool in reverse mode by supplying compressed air to the second air hose while permitting partial venting of the front pressure chamber through the first air hose.

Abstract: A pneumatic ground piercing tool includes a tail assembly including a tail nut and tail cap, the tail cap having a plurality of discharge ports for exhausting spent compressed air, the discharge ports opening into an annular space between a rearwardly opening recess of the tail cap and an air supply conduit such that the exhaust ports are shielded by a side wall of end cap from plugging when the ground piecing tool is operated in reverse mode.

Abstract: An impactor for use with a directional boring machine for replacement of underground pipes includes a bursting head having a rearwardly opening recess and a front end opening that communicates with the recess. An inlet pipe is connected at its front end to a distal end of the drill string and extends into the recess of the bursting head through the front end opening. A striker is mounted for sliding movement along the inlet pipe, and a distributing mechanism responsive to pressure fluid supplied through the drill string and inlet pipe causes the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the bursting head. The striker and distributing mechanism are mounted in a tubular housing, and a pulling connection is provided by which the impactor can be pulled by the drill string while the striker is delivering impacts against the head in the same direction as a pulling force exerted by the drill string.

Abstract: A joint connecting a pair of members rotatable about a common axis end to end includes a first member having a threaded end portion and a non-circular exterior surface rearwardly of the threaded end portion, a second member having a threaded socket wherein the threaded end portion of the second member can be engaged, and a non-circular exterior surface, a sleeve having a non-circular profile on an inner surface thereof whereby the sleeve can be slidably mounted on the non-circular exterior profiles of the first and second members when such profiles are brought into alignment by rotation of one member relative to the other in a manner effective to pass torque from one member to the other by means of the non-circular profiles, a first pair of alignable holes in the sleeve and first member to receive a fastener to secure the sleeve to the first member and a hole in the second member penetrating the threaded socket and positioned to receive a fastener to secure the second member to a third member in place of the