Abstract: A multi-indenter drill bit includes a plurality of indenters arranged on a drilling surface of a bit face. The ratio of the total indenter area to the bit face area is defined by a parameter KPI1 (expressed as a percentage), and the ratio of the average individual indenter area to the bit face area is defined by a parameter KPI2, (expressed as a percentage). The relationship between KPI1 and KPI2 is defined by an equation.

Abstract: A bidirectional cluster hammer reamer (“BCHR”) for use in a horizontal direction drilling system comprises a plurality of percussive hammers and bits arranged around a central drive rod. The central drive rod is translatable between a forward most position and a rear most position. The central drive rod is translated to the forward most position when the BCHR is being pulled through a previously drilled pilot channel. The central drive rod is translated to the rear most position when a reverse feed force is applied to the BCHR. When in the rear most position, the central drive rod cooperates with an air distribution assembly at the rear of the BCHR to expel a portion of a pressurized fluid to the exterior of the BCHR for clearing accreted debris.

Abstract: A hammer bit includes a bit body having a bit axis and a bit face, a first circumferential row of cutting elements mounted to the bit face, the first circumferential row located at an outermost radius of the bit face and extending around the bit axis, and a second circumferential row of cutting elements mounted to the bit face, the second circumferential row located radially inwardly adjacent the first circumferential row, wherein each of the cutting elements of the second circumferential row is a semi-round top insert. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of cutting elements of the first and second circumferential rows is between 0.1 and 0.5. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of the first and second circumferential rows is greater than 0.25.

Abstract: An apparatus for inserting a ground-loop for a geothermal heat-pump system comprises: a percussion mole (4); a first fluid pipe (5), connected to the mole (4), for conveying a heat-exchange fluid from the heat-pump system into the ground; and a second fluid pipe (6), connected to the mole (4), for returning the heat-exchange fluid to the heat-pump system. One of the first and second fluid pipes (5, 6) comprises an intake pipe for delivering a driving fluid to the mole (4) during insertion of the ground-loop and the other fluid pipe comprises an exhaust pipe for the driving fluid.

Abstract: An apparatus for drilling a hole in the ground has a hammer drill installed at a bottom of a rod assembled in multi-stages at support structure on the ground. The hammer drill has a pilot hammer drill and a reamer hammer drill coupled to each other through a key structure formed in the vertical direction so as to allow simultaneous rotations and up-and-down movements relative to each other.

Abstract: In one aspect of the present invention, a downhole fixed bladed bit comprises a working surface comprising a plurality of blades converging at a center of the working surface and diverging towards a gauge of the bit, at least on blade comprising a cutting element comprising a superhard material bonded to a cemented metal carbide substrate at a non-planer interface, the cutting element being positioned at a positive rake angle, and the superhard material comprising a substantially conical geometry with an apex comprising a curvature.

Abstract: A hammer assembly comprises a jack element substantially coaxial with an axis of rotation of a drill bit. The jack element includes a distal end extending beyond a working face of the drill bit. A porting mechanism within the bore comprises a first and second disc substantially contacting along a flat interface that is substantially normal to the axis of rotation. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The first disc comprises a first set of ports adapted to align and misalign with a second and third set of ports in the second disc. As the first disc rotates, the sets of ports are adapted to route a drilling fluid into a piston chamber where a porting mechanism causes the jack element to repeatedly extend further beyond the working surface of the drill bit and then retract at a constant frequency.

Abstract: A downhole percussive tool is disclosed comprising an interior chamber and a piston element slidably sitting within the interior chamber forming two pressure chambers on either side. The piston element may slide back and forth within the interior chamber as drilling fluid is channeled into either pressure chamber. Input channels supply drilling fluid into the pressure chambers and exit orifices release that fluid from the same. An exhaust orifice allows additional drilling fluid to release from the interior chamber. The amount of pressure maintained in either pressure chamber may be controlled by the size of the exiting orifices and exhaust orifices. In various embodiments, the percussive tool may form a downhole jack hammer or vibrator tool.

Abstract: In one aspect of the present invention, a drilling assembly comprises a drill bit comprising a bit body and a cutting surface. A formation engaging element protrudes from the cutting surface and is configured to engage a formation. At least one compliant member is disposed intermediate the bit body and formation engaging element and is configured to provide compliancy in a lateral direction for the formation engaging element.

Abstract: A method and apparatus for down-the-hole drilling. The drilling is carried out by a drilling device including a casing and a drilling unit. The drilling head includes a first drill for drilling a center hole, a second drill for reaming the center hole and a flushing flow arrangement including a first flusher for leading a flushing medium onto a drilling surface and a second flusher for returning of the flushing medium and drilling waste inside the casing. The first drill is removably coupled with the second drill to enable removal thereof from the hole. The casing is arranged to be drawn into a hole to be drilled by the drilling unit. The flushing medium is brought onto the drilling surface and returned therefrom by axially directed flow arrangements disposed in a cross-section view on an outer periphery of the first drill and/or in an inner periphery of the second drill.

Abstract: In one aspect of the present invention, a drill bit comprises an axis of rotation and a drill bit body that comprises a central bore and a working face, the working face comprising a plurality of fixed element cutting elements, a jack element extending from the working face and being coaxial with the axis of rotation, the jack element comprising a proximal end in mechanical communication with an oscillating hammer mechanism, the jack element also comprising a channel in fluid communication with the central bore, the channel directing a fluid flow into a formation, wherein a fluid volume defined by the hammer mechanism and the central bore is evacuated through the channel.

Abstract: A drill bit assembly comprises a bit body intermediate a shank and a working face. The shank is adapted for connection to a drill string. The drill string comprising a fluid passage at least partially disposed within the body. A hammer assembly is movably disposed within the fluid passage along it central axis, the hammer assembly comprises a proximal end stabilized by a centralized upper bearing and a distal end stabilized by centralized a lower bearing. The distal end protrudes out of the working face and the hammer assembly comprises a carrier between the upper and lower bearings. Wherein, under normal drilling operations the carrier is adapted to resist a fluid pressure within the fluid passageway such that the fluid pressure will further extend the distal end of the hammer assembly from the working face by pushing on the carrier.

Abstract: In one aspect of the present invention, a drilling assembly comprises a drill bit comprising a bit body and a cutting surface. A formation engaging element protrudes from the cutting surface and is configured to engage a formation. At least one compliant member is disposed intermediate the bit body and formation engaging element and is configured to provide compliancy in a lateral direction for the formation engaging element.

Abstract: The invention relates to a boring head for a ground-boring device displacing earth with a percussive action, comprising at least three boring head sections, of which the first section has a form optimized for the loosening and for guiding the device, the second section is optimized with regard to the radial displacement of the earth with low resistance to motion, and the third section has a fixed connection to the housing of the ground-boring device. Improved transmission of the advancing forces to the earth and consequently an improved advance of the ground-boring device can be achieved by at least two of the boring head sections being designed so as to be axially movable relative to one another in the longitudinal direction.

Abstract: A drill bit comprises a plurality of cutting blades arranged circumferentially, the cutting blades having a cutting edge formed by a connecting ridge line between a cutting face and a flank; and a tip formed by coupling radially inner ends of the cutting edges to each other at a center portion of a bit tip end, wherein at least one of the cutting blades has a first flank and a second flank, wherein the first flank has a blade tip side flank close to the cutting edge and a base end side flank formed on the base end side of the blade tip side flank, and wherein a tilt angle ?1 of the blade tip side flank 3a is smaller than a tilt angle ?2 of the base end side flank 3b which is tilted toward the axial direction.

Abstract: An apparatus for a drilling tool includes a pilot drilling bit, a reamer, and a pilot body which is disposed to support the reamer and the pilot drilling bit at the end of a casing tube. The reamer includes a closed position in which the parts of the tool are concentric with one another and displaceable through the casing tube, and an open position in which at least a part of the reamer is located radially outside the casing tube. The pilot body includes a male portion which extends through the reamer, the male portion of the pilot body forming a cam surface for transferring rotation energy to the reamer and for switching the reamer between the closed and open positions, and the male portion of the pilot body being insertable in a recess in the pilot drilling bit.

Abstract: A bit assembly in a drilling apparatus working by hammering and for rotating said assembly comprising of a pilot bit (1) drilling the central part of the hole and a ring bit (2), fitted in connection with said pilot bit(1) and furnished with cylindrical inner surface drilling the outer surface of said hole, and further, between the pilot bit (1) and ring bit (2) a blocking arrangement of mutual rotation and axial movement, whereby opening of said blocking arrangement makes it possible to pull the pilot bit (5) off the hole, while ring bit (2) remains in the hole, and the bit assembly comprises a casing tube and its extension (6) and an interlocking system, which is through a ring-shaped device (8) from the extension (6) of the casing tube adapted to transfer pulling force from the pilot or ring bit to the casing tube extension (6) and said interlocking system can be opened in order to continue drilling with the ring and pilot bits (1, 2) when the casing tube remains in its place.

Abstract: The present invention relates to a percussion hammer for enlarging drilled holes. The hammer comprises an external outer wear sleeve (5), an inner cylinder (7) mounted co-axially within the outer wear sleeve (5), a tubular torque shaft (3) disposed axially and centrally of the hammer assembly, and extending longitudinally through the assembly. The hammer further comprises a sliding piston (6) mounted for reciprocating movement within the inner cylinder (7) and outer wear sleeve (10) and about the tubular torque shaft (3) to strike a hammer bit (1) for reciprocal movement in a chuck (4) adjacent a forward end of the hammer assembly. The hammer bit (1) has a central bore (46) through which the torque shaft (3) extends, such that the torque shaft (3) protrudes forwardly of the hammer.

Abstract: In one aspect of the present invention a drill bit has a jack element with a distal end extending beyond a working face. A porting mechanism within the bore comprises first and second discs contacting along a flat interface. The first disc is attached to a turbine which is adapted to rotate the first disc with respect to the second disc. The discs comprise a first set of ports adapted to align and misalign with each other as the first disc rotates. The first set of ports is adapted to route a drilling fluid to extend the jack element.

Abstract: A down-the-hole hammer includes a piston movably disposed in a casing and a percussion bit at an end of the casing. The percussion bit includes an integral bit and shank and a pilot removably fastened at a forward end of the bit. A method of enlarging a preexisting hole is also provided.

Abstract: A downhole percussive tool is disclosed comprising an interior chamber and a piston element slidably sitting within the interior chamber forming two pressure chambers on either side. The piston element may slide back and forth within the interior chamber as drilling fluid is channeled into either pressure chamber. Input channels supply drilling fluid into the pressure chambers and exit orifices release that fluid from the same. An exhaust orifice allows additional drilling fluid to release from the interior chamber. The amount of pressure maintained in either pressure chamber may be controlled by the size of the exiting orifices and exhaust orifices. In various embodiments, the percussive tool may form a downhole jack hammer or vibrator tool.

Abstract: A drill bit assembly comprises a bit body intermediate a shank and a working face. The shank is adapted for connection to a drill string. The drill string comprising a fluid passage at least partially disposed within the body. A hammer assembly is movably disposed within the fluid passage along it central axis, the hammer assembly comprises a proximal end stabilized by a centralized upper bearing and a distal end stabilized by centralized a lower bearing. The distal end protrudes out of the working face and the hammer assembly comprises a carrier between the upper and lower bearings. Wherein, under normal drilling operations the carrier is adapted to resist a fluid pressure within the fluid passageway such that the fluid pressure will further extend the distal end of the hammer assembly from the working face by pushing on the carrier.

Abstract: A drill bit assembly comprises a bit body intermediate a shank and a working face. The shank is adapted for connection to a drill string. The drill string comprising a fluid passage at least partially disposed within the body. A hammer assembly is movably disposed within the fluid passage along it central axis, the hammer assembly comprises a proximal end stabilized by a centralized upper bearing and a distal end stabilized by centralized a lower bearing. The distal end protrudes out of the working face and the hammer assembly comprises a carrier between the upper and lower bearings. Wherein, under normal drilling operations the carrier is adapted to resist a fluid pressure within the fluid passageway such that the fluid pressure will further extend the distal end of the hammer assembly from the working face by pushing on the carrier.

Abstract: In one aspect of the invention, a method for drilling a bore hole includes the steps of deploying a drill bit attached to a drill string in a well bore, the drill bit having an axial jack element with a distal end protruding beyond a working face of the drill bit; engaging the distal end of the jack element against the formation such that the formation applies a reaction force on the jack element while the drill string rotates; and applying a force on the jack element that opposes the reaction force such that the jack element vibrates and imposes a resonant frequency into the formation.

Abstract: The invention is embodied in a percussion drill bit which comprises a steel body with a working front head portion having a front central zone and plural wing zones radiating from the central zone and being spaced at the outer circumferential edges thereof; first gauge-cutting PCD inserts are secured in the wing zones to extend forwardly at an angle relative to the axis of the bit, and of at least one second core-cutting PCD insert is non-axially secured to extend forwardly from the central zone.

Abstract: In one aspect of the present invention, a method has steps for forming a wellbore with a tool string bit having a body intermediate a shank and a working face. The bit body has a fluid passageway and at least a portion of a jack element is disposed within the body. The jack element also has an end forming at least a portion of a relief mechanism in the fluid passageway and a distal end substantially protruding from the working face. The bit connected to a tool string is deployed into a wellbore. Fluid is passed through the fluid passageway. A bottom of the wellbore is destructed by pulsing the fluid traveling through the passageway by opening and closing the relief mechanism.

Abstract: In one aspect of the invention a drill bit comprises an axis of rotation a body and a working face. The body comprises a fluid passageway with a first seat and houses a jack element substantially coaxial with the axis. A stop element is disposed within the passageway and has a first near-sealing surface. The jack element has a shaft intermediate an indenting end and a valve portion. The valve portion has a second near-sealing surface disposed adjacent the first near-sealing surface and a second seat disposed adjacent the first seat. As a formation strongly resists the jack element, the distance between the sealing surfaces narrows. This causes an increase in fluid pressure within the passageway and forces the indenting end down into the formation. This movement of the jack element relieves the pressure build up such that the formation pushes the jack element back, thereby oscillating the jack element.

Abstract: An elongated pilot member is forced into the ground and an auger with a hollow stem is positioned around the pilot member and rotated to move the auger into the ground. A second elongated member is coupled to the pilot member and an upward force is applied to the auger stem or to an extension thereof to enable a downward force to be applied to the second elongated member to force the second elongated member and the pilot member into the ground. The second elongated member and the auger stem then are attached together and to a foundation support member for providing support for a foundation.

Abstract: A percussion bores for forming borer in a stone material and including a chisel stem (2) having a prismatic cross-section and provided with a chiseling head (3) and at least one radial opening (4), a twist drill (6) extending through the cylindrical through-bore (3) of the chisel stem and projecting beyond the chiseling head (7), a drilling head (10) with cutting elements (9) provided at the projecting end of the twist drill and a shank (12) provided at another end of the twist drill, and a stop (13) provided between the shank (12) and the chisel stem (2), with a drill stem being offset radially inwardly with respect to an outer diameter of the shank in the region of the stop.

Abstract: An impact drill for both reciprocation and rotation to drill into a surface and provided with a plurality of frustum cutters. The frustum cutters are arranged in one or more arrays and are spaced radially from the axis of rotation of the drill and are spaced axially from the tip of the drill.

Abstract: A underreamer drill bit assembly including a pilot bit and extendable underreaming arms operatively connected to the pilot bit. The underreaming arms have an extended position for underreaming, and a retracted position in which the overall diameter of the underreamer drill bit assembly is less than the inside diameter of the well casing, permitting the entire bit assembly to be withdrawn through the well casing. In another aspect of the invention, the bit assembly is operatively connected to a dual wall pipe assembly. A supply of compressed air is conducted through the annulus of the dual wall pipe assembly to a down hole pneumatic hammer. Exhaust air from the down hole hammer is directed to the bit assembly for continuous removal of drilling debris through a central evacuation tube of the dual wall pipe assembly. In another aspect of the invention, a pressurized, incompressible fluid is injected into the annulus between the well casing and the downhole pneumatic hammer.

Abstract: A drill bit is provided for drilling holes in hard, reinforced material, including reinforced concrete. According to one aspect of the invention, wear-resistant inserts are provided in a cross-shaped pattern. The inserts ensure that the entire bottom surface of the drilled hole is engaged during each drill bit revolution. The inserts may be secured in pockets or slots. Fluid entry ports may be located between the inserts for efficient handling of drilling fluid and removal of drilled material, without impairing the structural integrity of the drill bit. According to another aspect of the invention, the drilling surface is separated into two or more stages to increase drilling efficiency, especially through composite material such as reinforced concrete.

Abstract: A masonry drill bit 1 having an active diameter of D, comprising a shaft 3 and a tip 5 for engaging a workpiece, the tip 5 including a central portion 11 extending ahead of an outer portion 13, wherein the central portion 11 has a width of at least 0.25D and is shaped to act as a chisel during percussion drilling, and wherein the outer portion 13 is shaped to cut a workpiece as the drill bit rotates. By virtue of the drill bit tip 5 configuration as described and claimed herein, a masonry drill bit 1 having improved performance is provided.

Abstract: A percussive drilling mechanism includes a percussive hammer and a drill string connected to the hammer. The drill string includes a plurality of identically shaped shank rods interconnected to one another. To extend the drill string, a trailing one of the shank rods is removed from the hammer, and a new shank rod is interposed between the hammer and that removed shank rod.

Abstract: A drilling tool, especially for the rotary percussion drilling of preferably rock, has a drilling body equipped toward the drilling side preferably with cutting bits, and with an axially arranged bore for receiving an exchangeable centering drill. In order to achieve axial movability and a reliable rotational takeup of the centering drill in the drilling tool, the drilling tool has a transverse bore which is arranged centrally relative to its drill longitudinal axis and into which can be inserted a bar-shaped or tubular holding means which centrally penetrates a corresponding recess on the shank of the centering drill so that the centering drill can be moved in the axial direction.

Abstract: A underreamer drill bit assembly including a pilot bit and extendable underreaming arms operatively connected to the pilot bit. The underreaming arms have an extended position for underreaming, and a retracted position in which the overall diameter of the underreamer drill bit assembly is less than the inside diameter of the well casing, permitting the entire bit assembly to be withdrawn through the well casing. In another aspect of the invention, the bit assembly is operatively connected to a dual wall pipe assembly. A supply of compressed air is conducted through the annulus of the dual wall pipe assembly to a down hole pneumatic hammer. Exhaust air from the down hole hammer is directed to the bit assembly for continuous removal of drilling debris through a central evacuation tube of the dual wall pipe assembly. In another aspect of the invention, a pressurized, incompressible fluid is injected into the annulus between the well casing and the downhole pneumatic hammer.

Abstract: A rock drilling tool includes a pilot bit screw threaded into a front end of a drill rod. A reamer is mounted on the outside of the pilot bit. The reamer includes a central opening having a front portion and a rear portion. The front portion is connected to the pilot bit, and the rear portion constitutes a stiffening sleeve which extends around the outside of the drill rod.

Abstract: A masonry drill bit 1 having an active diameter of D, comprising a shaft 3 and a tip 5 for engaging a workpiece, the tip 5 including a central portion 11 extending ahead of an outer portion 13, wherein the central portion 11 has a width of at least 0.25 D and is shaped to act as a chisel during percussion drilling, and wherein the outer portion 13 is shaped to cut a workpiece as the drill bit rotates. By virtue of the drill bit tip 5 configuration as described and claimed herein, a masonry drill bit 1 having improved performance is provided.

Abstract: A drill bit assembly includes a driver adapted for attachment to a down hole pneumatic hammer. A pilot bit is coupled to the driver in a manner permitting rotational and axial movement between driver and pilot bit. A series of underreamer arms are disposed intermediate the driver and the pilot bit and engage a centrally disposed cam block on the pilot bit. Pivot pins of the underreamer arms are journaled in and move with the driver during partial rotation of the driver during arm deployment and retraction. Passageways in the driver and pilot bit direct compressed air to the working surface of the bit for discharging particles upwardly through channels in the bit and driver. Inclined surfaces on the underreaming arms cooperate with the lower end of a casing to contribute to arm retraction prior to removal of the assembly through the casing.

Abstract: A percussive blow assisted rotary drill includes an axially extending shank (1) with a leading end face (3) and an axially extending outside surface (2) containing a helically extending drilled material removal groove (4, 5). At least one hard metal cutting plate (6) extends across a diameter of the shank and has a base part fixed in a continuous groove (9) in the leading end face (3) of the shank (1). The base part (10) is reinforced by an outwardly extending projection (12) in at least one of its side surfaces extending across the shank diameter. Preferably, the projections forms a part of a circle and are centered between the opposite ends of the cutting plate. The continuous groove (9) has a recess in at least one of its side surfaces shaped to coincide with the shape of the outward projection (12) on the cutting plate. Accordingly, the base part (10) is secured in a positively locked manner and preferably is centered in the leading end face of the shank.

Abstract: An eccentric drilling tool comprises a guide member (10) rotatably centered by the mouth of a casing tube (11) that follows the tool downhole during drilling. A pilot bit (23) on the guide member (10) is provided with axially oriented hard metal pilot button inserts (57, 57.sup.I -57.sup.III) peripherally thereon directed to define the diameter of the pilot hole to be cut during drilling. A laterally extending eccentric bit (22) behind said pilot bit (23) has axially oriented hard metal reaming button inserts (48-51) at the eccentric top portion thereof directed to ream up the pilot hole to a maximum diameter. The eccentric bit (22) is movably supported relative to said guide member (10) between a drilling position, in which the eccentric bit (22) projects laterally beyond said casing tube (11) so as to drill jointly with said pilot bit (23) a hole larger than said casing tube (11), and a retracted position, in which the drill bit can be retracted or lowered through the casing tube (11).

Abstract: Drill steel or bit apparatus includes a primary drill bit having a base and a stem, a drill tip, and a bore extending longitudinally through the base, the stem, and the tip, and a pilot drill bit having a base and a stem, and a tip, and the stem and the tip extend through the longitudinal bore in the primary drill bit. The pilot drill bit includes a longitudinally extending bore through which compressed air flows. The base of the pilot drill bit is impacted by a drill piston and the base of the pilot drill bit in turn impacts the primary drill bit. Drilling is accomplished by the tips of both the pilot drill and the primary drill bit.

Abstract: Disclosed is a single-pass notching and drilling tool. The tool comprises an adaptor having a first threaded end for coupling with a power source, an opposed second threaded end, an enlarged diameter portion adjacent to the first threaded end and having a first abutment face and a mediate portion adjacent to the first axial abutment face and adjacent to the second threaded end. There is also a drill portion joined to the second threaded end of the adaptor and having a second axial abutment face. The tool further comprises a notching tool comprising a body having a central bore rotatably engaging the mediate portion of the adaptor. The notching tool is freely rotatable about the mediate portion independent of the rotation of the adaptor. The axial movement of the notching tool is bounded by the first and second axial abutment faces. Disclosed also is a method of drilling a blast hole with the single-pass notching and drilling tool.

Abstract: A drill tool for rotary and/or percussion drilling with drill rod means (14) within casing tube means (15) comprises a centric cutting bit (11) and an eccentric reamer cutter (12), both provided with hard metal inserts. For purposes of obtaining a life of the drill tool as long as possible the first frontal insert (23) on the reamer cutter (12) is positioned in front of the first peripheral insert (18) when seen in the rotational direction (D) during drilling, and the centric cutting bit (11) provided with more inserts on the half (38) of its front surface opposed to the reamer cutter (12) during drilling than on the other half (39).

Abstract: A blast hole drill bit is disclosed for forming longitudinally extending grooves in already drilled blast holes, having a body with a forward face and a rearwardly extending pilot diameter. One or more radially extending wings are located at the rearmost part of the pilot diameter and are V-shaped when viewed in plan. Wear resistant compacts form a part of the wings and have a V-shaped cutting edge.

Abstract: A reciprocating rotary drill bit is disclosed to include a coupling member for coupling the drill bit to a source of drill bit drive power and a cutter member for drilling into a workpiece. The coupling member and the cutter member are slidably associated and include overlapping protruding portions which delimit the upward and downward travel of the cutter member with respect to the coupling member. The slidable association permits reciprocation of the cutter member with respect to the coupling member as the drill bit is rotated into the workpiece. The coupling member also includes protrusions which extend into grooves defined in the cutter member to rotationally secure the two members whereby the cutter member rotates when the coupling member rotates.

Abstract: A replaceable cutter head for rotary percussion drills having a pilot cutter on the end of a drill stem with a main cutter head surrounding the pilot cutter, the main cutter head having hammering/chipping cutters and milling cutters arranged along radial lines extending from the pilot cutter to the outer periphery of the main cutter head in alternate arrays, either along the radial cutter lines or on alternate radial cutter lines, or both.

Abstract: The present sampler is adapted to take soil samples from the ground surface, from a borehole sunk by other tools, as well as for drilling shallow boreholes. The sampler is provided with an air-operated percussion mechanism and a soil sample receiving sleeve arranged coaxially thereto. The side surface of the sleeve is provided with an annular ridge having a diameter somewhat larger than the diameter of the percussion mechanism housing. This feature enables a reduction of the forces applied to the sampler to sink it into or withdraw it from the soil.

Abstract: A fatigue resistant anvil bit is described for use on a percussion rock drill. The anvil bit has a shank having a substantially uniform cross section terminated in a threaded end portion. A bit head is threadably mounted on the end portion having a diameter substantially greater than the bit shank. An anvil ring is shrunk fit on the shank engaging the bit head to provide lateral support and minimize the creation of fatigue fractures.