Abstract: A PDC bit for cutting a hole below a point in a formation, the diameter of the hole being greater than the diameter of the hole above the point, comprising: a bit body having an axis of rotation, a first cutting portion having a first radial extent from the axis of rotation, a second cutting portion that is not axially spaced apart from the first cutting portion and that has a second radial extent that is greater than said first radial extent, wherein the total imbalance forces resulting from engagement of said first and said second cutting portions with the formation are balanced such that the resulting torque on the bit is minimized and in particular, the component of the torque on the bit about an axis normal to the axis of rotation is minimized. In some embodiments, the bit has a central recessed portion on its face, which receives a short "core" portion that enhances stabilization of the bit.

Abstract: Drilling tool with a drill head with an end face pointing in the feed direction and which has a main bit, which forms a drill point located in the drill axis and the bit is inclined on either side in a substantially roof-shaped manner and the tool has drilling dust grooves. The main bit has a primary cutting edge, which extends radially over at least one side of the main bit, and a secondary cutting edge, which extends radially over substantially the remaining length of the main bit and is axially set back with respect to the primary cutting edge counter to the feed direction by at least the amount of feed in millimeters per revolution.

Abstract: A method for directional boring of all earth formations such as dirt, sand, rock and/or any type combination of formations, utilizing a bit body containing fixed and semi-floating cutting points and one or more fluid channels for the purpose of lubricating and dispersing cut and/or fractured formations.

Abstract: A drill bit adapted to walk predictably during drilling is disclosed, comprising: a bit body having a longitudinal axis and a bit face having an active zone and a passive zone, and a plurality of cutters on the bit face, a first portion of said cutters being positioned in the active zone and a second portion of said cutters being positioned in the passive zone, the first portion of cutters being more aggressive than the second portion. This the difference in aggressiveness of cutters in the first and second portions is achieved by maximizing the effect of one or more of seven features of the bit. These features include: cutter size, cutter tip profile, blade relationship, cutting structure, back rake, gage pad design and balance. Application of the principles of the present invention result in a large imbalance vector being oriented toward the leading half of the active zone.

Abstract: A method for directional boring of all earth formations such as dirt, sand, rock and/or any type combination of formations, utilizing a bit body containing fixed and semi-floating cutting points and one or more fluid channels for the purpose of lubricating and dispersing cut and/or fractured formations.

Abstract: A drill bit for directional boring of all earth formations such as dirt, sand, rock and/or any type combination of formations, utilizing a bit body containing fixed and semi-floating cutting points and one or more fluid channels for the purpose of lubricating and dispersing cut and/or fractured formations.

Abstract: A drill including an elongate shaft (2) a rear end (5) of which is formed as a shank, and a drilling head (10) provided at the front end of the shaft (2) and having central cutting edges (11, 12) extending from a leading center point (14), which is provided substantially at an extension of a shaft axis, backward toward a circumference of the drilling head, and at least one minor cutting edge (13) a portion (n) of which extending transverse to the shaft axis projects beyond a circumference of the shaft (2), with the projecting portion (n) having a length equal from about 10% to 100% of an entire length of the minor cutting edge.

Abstract: A directional boring apparatus is disclosed where the apparatus is controlled through a method which includes deviating a drill head from a straight path into a desired direction angled away from the straight path. The deviation is achieved by applying an axial force to the drill head when a drill head cutting member is positioned within an arc of rotation through which the desired direction passes. The drill head is retracted when the cutting member is outside of the arc of rotation.

Abstract: A method and apparatus for reaming or enlarging a borehole with enhanced stability. A pilot stabilization pad (PSP) having an axially and circumferentially tapered entry surface and a circumferential transition surface above is employed to enhance the transition from the smaller diameter borehole to be enlarged while accommodated the side force vector generated by the cutting assembly used to effect the enlargement. In addition, one or more eccentric stabilizers are employed above the reaming apparatus to laterally or radially stabilize the bottomhole assembly, which may comprise either a straight-hole or steerable, motor-driven assembly.

Abstract: A reaming apparatus for enlarging a borehole, including a tubular body having one or more longitudinally and generally radially extending blades circumferentially spaced thereabout. Each of the blades carries highly exposed cutting elements, on the order of fifty percent exposure, on its profile substantially all the way to the gage. At least one of the blades is a primary blade for cutting the full or drill diameter of the borehole, while one or more others of the blades may be secondary blades which extend a lesser radial distance from the body than the primary blade. A secondary blade initially shares a large portion of the cutting load with the primary blade while the borehole size is in transition between a smaller, pass through diameter and drill diameter. It functions to enhance the rapidity of the transition while balancing side reaction forces, and reduces vibration and borehole eccentricity.

Abstract: A roof drill bit for drilling a bolt hole in a mine roof comprises a body defining a longitudinal axis of rotation and having an external periphery and a front face. A longitudinal fluid channel is formed in the external periphery for conducting a flow of flushing fluid to the front face. An imaginary longitudinal plane which contains the axis of rotation serves to bisect the front face into first and second sides. A cutting edge arrangement is defined by at least one cutting insert mounted on the body. The insert is positioned to be acted upon by the flow of flushing fluid. At least one support pad is mounted on the external periphery for balancing cutting forces acting on the drill bit. The cutting arrangement is asymmetrical with respect to the axis of rotation such that the cutting edge arrangement is disposed on one of the sides, and the other side is substantially free of the cutting edge arrangement.

Abstract: The present invention is a drill bit having a multi-level gage defining the outermost radius of the bit, at least one portion of the gage extending longitudinally closer to the bit face than another portion.

Abstract: A method and apparatus for drilling a horizontal controlled borehole in the earth includes a drill frame, a drill string and a downhole tool. The drill frame includes a wrench attached to the frame for assisting in breaking and forming joints. The downhole tool includes removable blade assemblies having, for example, stepped or spade-like profiles and hard facing at areas of primary contact with the soil. When fluid is added for cooling, lubricating and flushing away cuttings, the downhole tool can include a nozzle parallel to the centerline of the longitudinal axis of the drill string, a check valve means for preventing downhole particles from entering the fluid passageway and/or a transmitter protecting waterproof plug for diverting fluid to a fluid passageway and for allowing an on-board downhole transmitter to be near the drill bit. Also, the blade assembly can be placed so as to divert fluid from the nozzle to an acute angle relative to the longitudinal axis of the drill string.

Abstract: A rotary drill bit for cutting an earth formation is provided. The drill bit includes a bit body rotatable about its longitudinal axis. A cutting face is provided on the bit body, with a concave central region and a raised outer periphery terminating at bit shoulder. The bit shoulder is concentric with and substantially parallel to the longitudinal axis of the rotary drill bit. A plurality of bit stabilizing pads are circumferentially disposed about the bit's shoulder. A plurality of stationary cutter elements are fixedly mounted to the cutting face in a selected pattern to provide a region of high cutter density on one side of the cutting face, and a region of low cutter density on the other side of the cutting face. The drill bit cuts earth formations as the bit body is rotated about its central axis. The stationary cutter elements operate to cut into the lower side wall of the wellbore as the bit body is rotated, causing the rotary drill bit to walk to the right.

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: A flushing device for drilling tools comprises a guide member (10) carrying a drill bit (20) and being rotatably centered by the mouth of a casing tube (11) which is adapted to follow the drilling tool downhole during drilling. The drill bit (20) has a bit portion (22) that projects laterally beyond and is spaced axially in front of the casing tube (11) so as to drill a hole larger than the casing tube (11). There are external flushing grooves (70,71) on the guide member (10) adapted to lead the outflow of flushing medium and debris from the hole during drilling into the casing tube (11). At least one of these grooves (70) extends from front to rear of the guide member (10). One or more further grooves (71) are open towards said rear while ending blindly into the periphery of the guide member (10) spaced from its front. By retraction of the guide member (10) its front enters the casing tube (11).

Abstract: A cutting tool (10) for removing metal tubular members held in stationary position downhole from a well bore and adapted to be inserted within a well. The cutting tool (10) includes a plurality of elongate blades (32,34) on the cylindrical body (22) of the cutting tool (10) which extend below the bottom of the tool body (22). Cutting elements (42) of a predetermined size and shape are arranged in a symmetrical predetermined pattern on the lower portion of each blade (32,34) in a plurality of predetermined transversely extending rows below the tool body (22). The cutting elements (42) in adjacent transverse rows for each blade (32) are staggered horizontally and have different concentric cutting paths. Preferably, the cutting elements (42) in corresponding transverse rows on adjacent blades (32,34) are staggered and have different concentric cutting paths.

Abstract: A drilling tool is followed by a casing tube (11) down the drilled hole. The mouth of the casing tube (11) centers rotatably a guide member (10) which receives rotation and impact energy via the interior of the casing tube (11). A drill bit (20) consists integrally of an axially protruding pilot portion (23), a sidewise projecting eccentric portion (22) and a rear shaft (21). The shaft (21) extends pivotally and axially movably into an eccentrically disposed bore (24) in the guide member (10). Axially spaced peripheral end grooves (30,32) extend in opposite direction from an axial cam groove (31) on the shaft (21) and are engaged by a follower (28) in the guide member (10) defining positively the axial and angular movability and positions thereof relative to the drill bit (20). In the forward end groove (32) the follower (28) maintains the drill bit (20) axially in drilling position (FIG.

Abstract: Drill tools with eccentric bits for drilling a hole having a large diameter generally include a bit for swinging out to an eccentric position for drilling, and for swinging into a non-eccentric position for removal from a tubular casing. Relatively complicated structures are required for effecting bit movement, and it is often difficult to remove the bit for replacement or repair.

Abstract: A drill bit for producing an undercut. The drill bit includes a shaft and a cutting edge that is disposed asymmetrically radially beyond the shaft in a front end portion of the drill bit. A planar guide surface is provided on a conical end face of the drill bit. This guide surface is disposed radially opposite the cutting edge. The guide surface terminates at a concentric tip of the drill bit.

Abstract: A rock drill having a drilling head which, in an asymmetric arrangement relative to the main cutting tip, has at least one additional secondary cutting tip, the angle enclosed between the single cutting edge of the main cutting tip and the secondary cutting tip being formed as an acute angle.

Abstract: A whirl resistant drill bit is disclosed for use in rotary drilling. The drill bit includes a generally cylindrical bit body with a plurality of cutting elements extending out from a lower end surface. The cutter elements are grouped in sets such that a first set of cutters are disposed at substantially an equal radius from a center of the bit body to create a groove in the material being drilled. A second set of cutters is connected to the lower end surface with each cutter therein in overlapping radial relationship with each other and extending a maximum distance from the lower end surface less than that of the first set of cutters. At least one cutter of the second set is in overlapping radial relationship with at least one of the cutters within the first set of cutters. This cutter arrangement causes the drill bit to cut grooves within the formation material that tends to prevent destructive bit whirl. Further, adjustments can be made to vary the back rake angle and side rake angle to prevent bit whirl.

Abstract: There is disclosed herein an apparatus for providing an underground tunnel utilizing a steerable pneumatically powered, elongated percussive downhole hammer having a forwardmost cutting bit which is asymmetrically configured with respect to the elongation axis of the hammer. This hammer is steered through the ground, that is, made to move along a straight path or a particular curved path, by controlling the way in which it is pneumatically powered and/or the way in which it is urged forward and/or the way in which its cutting bit is rotated.

Abstract: The invention relates to a simplified and reliably functioning drill tool for a sinker drill for drilling in loose earth, such as when reinforcing the foundations in connection with building. The drill tool according to the present invention is in two parts and consists of an upper cylindrical transition piece (1), its central coinciding with the rotary axis of the drill tool, and provided withan eccentric, cylindrical hole (4), and of a lower reamer piece (2) provided with an upwardly directed shaft (3) to fit into the hole. In operating position the shaft (b 3) is fully inserted into the hole (4) and the transition piece (1) and reamer piece (b 2) cooperate. In extraction position the shaft (3) is partially withdrawn from the hole (4) to permit the drill (1,2) to be drawn up through a casing-tube.

Abstract: A rock cutting assembly consists of a rock cutting roller, a shaft on which it is mounted, and a means for varying the mass of the assembly about the drive axis, to vary the balance of the assembly about that axis. Preferably two rollers are mounted on a common drive axis, the axes of the rollers being diametrally opposed and eccentrically displaced by the same distance from the drive axis. The mass-varying means may be a cavity or cavities in the hub or hubs, with means to introduce fluid into and extract it from the cavity or cavities. Alternatively the means may be a weight mounted to permit adjustment to vary the degree of imbalance.

Abstract: A drill tool for rotary and/or percussion drilling includes a drill string and a cutting apparatus connected to a lower end of the drill string. The cutting apparatus has an intermediate portion which is rotatable with the drill string and includes an outer surface, a reamer is mounted eccentrically on the intermediate portion for rotation relative thereto about a longitudinal axis. The reamer includes an inner surface facing the outer surface. The reamer is driven by an arrangement comprised of a tongue disposed on either of the inner and outer surfaces and a pair of circumferentially spaced shoulder surfaces disposed on the other of the inner and outer surfaces. The tongue is selectively engageable with the shoulder surfaces along an area of contact having an upper longitudinal end which terminates below an uppermost end of the reamer, and a lower longitudinal end which terminates above a lowermost end of the reamer.

Abstract: A drill bit for drilling bore holes in underground formations comprising a bit body with a connecting spigot for connecting to a drill string or the like, and a cutting head which comprises a circumferential face extending parallel to its longitudinal axis and an end face having a drilling axis which is aligned with the axis of the connecting spigot. The drilling axis is parallel to and is offset relative to the axis of the cutting head. It is preferred that the end face is, at least in part, conical in shape.

Abstract: The invention relates to an arrangement for drilling in soil and rock while simultaneously lining the drill hole with a lining tube. The arrangement includes an asymetric guide which is non-rotatably connected to a drill stem or like element, and an eccentric drill bit or crown which is journalled for limited rotation in the guide. The guide is arranged to lie solely against a part of one side of the inner surface of the lining tube during a drilling operation. Advantageously, the guide is supplemented with a guiding portion on the shank part of the drill bit located opposite the first guide. The drill arrangement enables wide adjustments to be made to the eccentric setting of the drill bit, and makes possible an advantageous forming of the cutting geometry of the drill bit.

Abstract: An elongated upstanding shank is provided including a ground piercing lower end and an upper end including structure for applying rotary torque to the shank. The lower end portion of the shank supports a generally horizontally disposed U-shaped blade therefrom including a pair of generally parallel upper and lower arms joined at one pair of corresponding ends by an integral curved bight portion. The other pair of corresponding ends of the arms are supported from the shank at points spaced therealong. At least the lower arm and the adjacent portion of the bight portion include a sharpened edge facing outwardly of one side of an upstanding plane containing the U-shaped blade and the shank. The blade comprises a thick elongated strap metal member bent into U-shaped configuration and the portions of the blade defining the lower arm and the adjacent portion of the bight portion are disposed with their width extents disposed generally normal to the aforementioned plane.

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 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: A rock drill for rotary blow drilling with a drilling head arranged at the free end of the drill shaft, which at least partially consists of hard metal. The drilling head the end face of which is circular disc shaped or circular ring shaped includes a formed piece of solid hard metal. Cutting bodies are machined out of the end of this piece of hard metal which cutting bodies have the shape of pyramids or truncated pyramids and taper with increasing distance from the drill shank.

Abstract: Boring apparatus comprising a tubular casing containing a cylindrical body adapted for being driven by a boring rod and a filter body adjacent the cylindrical body. A boring tool is mounted outside the tubular casing at the end of the filter body. The filter body has a cross-section of polygon shape with axially extending edges in contact with the inner surface of the tubular casing to define clearance spaces between the inner surface of the tubular casing and the outer surface of the filter body. The cylindrical body has axial grooves extending to the clearance spaces for passage of boring particles. The cylindrical body can also be provided with annular grooves. Preferably, the cylindrical body and filter body are constituted as a single unit.

Abstract: An earth auger having an integral or one piece cutting blade and pilot element so arranged that the pilot element is spaced downwardly from the shaft of the auger; the cutting blade also having a curved edge swept back from the axis of the auger to provide a slicing action as well as "threading" action to facilitate penetration of the auger into the ground.

Abstract: A boring tool, especially for drill hammers with a hollow drill core bit, which the inner thread of the hollow drill core bit connected directly to the borer shank and in which a corresponding outer thread provided on a holding mandrel form a part of the borer shank have a wire coil-thread insert inserted therebetween. The hollow drill core bit and the borer shank are provided with centering surfaces located between the windings of the wire coil thread insert and arranged in centering engagement with each other.

Abstract: A drill for rock comprising a boring head arranged on one end of a drill shank and having radially projecting wings, an axial centering projection which projects in a boring direction in front of the wings, said wings and said projection constituting carriers of eccentrically arranged cutter bodies and a centering cutter body, respectively. Breaker surfaces are formed on the wing surfaces between the cutter bodies, respectively, pointing to the centering point of the centering cutter body. Each surface of the boring head located between the wings has at least one jacket line which extends longitudinally to the axis of the boring head and directly joins to a jacket line of the outer surface of the centering projection and is inclined relative thereto at an obtuse angle.

Abstract: A drill bit for use in concentrically arranged dual drill strings. The bit has an outlet eccentrically arranged respective to its longitudinal axial centerline, and a formation engaging surface made of a plurality of spiraling faces which diminish in area as the cutting face curves about and toward the outlet. The area located between the spiraling faces form fluid conveying passageways through which a jet of fluid is directed toward the outlet, thereby carrying therewith cuttings formed by the spiral faces of the bit.

Abstract: A whirl resistant drill bit is disclosed for use in rotary drilling. The drill bit includes a generally cylindrical bit body with a plurality of cutting elements extending out from a lower end surface. The cutter elements are grouped in sets such that a first set of cutters are disposed at substantially an equal radius from a center of the bit body to create a groove in the material being drilled. A second set of cutters is connected to the lower end surface with each cutter therein in overlapping radial relationship with each other and extending a maximum distance from the lower end surface less than that of the first set of cutters. At least one cutter of the second set is in overlapping radial relationship with at least one of the cutters within the first set of cutters. This cutter arrangement causes the drill bit to cut grooves within the formation material that tends to prevent destructive bit whirl. Further, adjustments can be made to vary the back rake angle and side rake angle to prevent bit whirl.

Abstract: A reaming apparatus for enlarging a borehole, including a tubular body having one or more longitudinally and generally radially extending blades circumferentially spaced thereabout. Each of the blades carries highly exposed cutting elements, on the order of fifty percent exposure, on its profile substantially all the way to the gage. At least one of the blades is a primary blade for cutting the full or drill diameter of the borehole, while one or more others of the blades may be secondary blades which extend a lesser radial distance from the body than the primary blade. A secondary blade initially shares a large portion of the cutting load with the primary blade while the borehole size is in transition between a smaller, pass through diameter and drill diameter. It functions to enhance the rapidity of the transition while balancing side reaction forces, and reduces vibration and borehole eccentricity.