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: A rock bit has a body and three cutters that include generally conical surfaces, at least one of which contains an outermost, circumferential row of heel teeth that dislodge cuttings from the borehole wall and bottom. The heel teeth form a corner with the borehole wall with successive contact points defined by the path of outer edges of the heel teeth while rotating into, and prescribing, the corner as it spirals downwardly during drilling. The rotational axis of the cutter is offset from the geometric centerline or intended rotational axis of the bit. Stabilizing pads extend outwardly from the body, each concluding in a surface that contains a low-friction, wear-resistant surface that engage the wall of the borehole. The center of each surface is located directly across from the contact point of an opposed cutter.

Abstract: A method and apparatus for deviating the direction of a borehole. The method comprises the steps of rotating a boring head underground through a material which is to be cut and oscillates the boring head to achieve a desired direction change. The boring head has one or more roller cones and may further comprise a deflection structure. The deflection structure may be separately mountable to the boring head or may be integrally formed with the boring head. The boring head is rotated to bore a generally straight hole. To change direction, the roller cone is oriented to achieve the desired direction change and oscillated to deviate the direction of the borehole. Oscillation of the roller cone may be carried out by oscillating the drill string, the boring head and/or the roller cone.

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 directional boring machine equipped with a boring head comprising a blade assembly. The blade assembly may comprise a plurality of blades with deflecting surfaces. Alternately, the blade assembly has a single, stepped or serrated blade. The serrated blade assembly has a planar blade which is tapered in thickness and width from its base to its forward end. The forward end has teeth cut away on the backside to provide a recess or relief space for cuttings during the drilling process. A relief space or slot also is provided between the front two teeth for the same purpose. The blade is divided into two halves, and the halves are offset so that each of the teeth on each half provides a separate cutting point. The blade is angled in an upward direction relative to the base of the blade assembly to improve penetration and cutting actions. The blade assembly in combination with the boring head body provides exceptional cutting performance in a variety of soils and rock.

Abstract: An earth-boring bit has a bit body and at least a pair of cantilevered bearing shafts depending downwardly and inwardly therefrom. A first cutter is mounted for rotation on one of the bearing shafts and has a region of contact with the sidewall of the borehole. A second cutter is mounted for rotation on another of the bearing shafts and has a region of contact with the sidewall of the borehole that is non-opposite that of the first cutter. Stabilization is provided by a stabilizer pad carried on the bit body and arranged to be opposite the contact regions of the first and second cutters.

Abstract: The tunnel drilling machine or tube-driving machine for hard rock drilling has a drill head (19) supporting drilling tools (1 to 18) which has a diameter which is less than the diameter of the bore. The geometric axis of the circle of the envelope of the tools of the full-width drill head (19) is disposed eccentrically in relation to the linear tunnel axis (22) or the axis of rotation (21) or can be displaced.

Abstract: A drill bit includes a rolling cutter having a plurality of closed-end circumferential rows of teeth protruding from the body of the cutter. At least one of the rows of teeth lies along a path defined either by multiple helical segments or a canted planar periphery.

Abstract: The present invention relates to an improved roller cone core bit comprising a plurality of cone cutters facing inboard and a single cone cutter facing outboard. The single outboard facing cone cutter provides additional cutting elements for cutting a core. The single outboard facing cone cutter also creates an unbalanced loading condition on the core bit causing the bit to drill smoother than conventional reversed cone core bits.

Abstract: A drill bit includes a rolling cutter having a plurality of circumferential rows of teeth protruding from the body of the cutter. At least one of the rows of teeth is a closed-end circumferential row located on the surface of the cutter along a closed-end circumferential path. The latter is a non-circular curve defined by a surface intersecting the body of the cutter obliquely with respect to its longitudinal axis.

Abstract: Directional boring bits (1100, 1200) are disclosed which have at least one roller cone (1202, 1104) and also each define a deflecting surface (1104) for deflecting the boring bit when the bit is advanced without rotation. The borehole can be curved by pushing the bit forward without rotation.

Abstract: Directional multi-blade boring heads (1000, 1050) are disclosed which have first and second blades (1030, 1032) which each define a deflecting surface (1036, 1038) for deflecting the boring head when the head is advanced without rotation. At least one intermediate blade (1034) extends between the deflecting surfaces in a three blade design. In a four blade design, a second intermediate blade (1042) extends on the side opposite the first intermediate blade (1034). The boring head is particularly effective in drilling a straight borehole through a variety of soil conditions when the boring head is simultaneously rotated and advanced along the direction of boring.

Abstract: An earth-boring bit is provided with three cutters, two of the three cutters are provided with heel disk cutting elements defined by a pair of generally oppositely facing disk surfaces that generally continuously converge to define a circumferential heel disk crest. One of the two cutters having heel disk elements is further provided with an inner disk cutting element.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. Each cone is provided with cutting teeth which are inclined in the direction of cone rotation and which cover the cone surface in a manner which provides scraping of substantially the entire bottom surface of the hole being drilled and in a manner providing efficient scraping and crushing action.

Abstract: A rotary drill bit comprises a bit body having a shank for connection to a drill string and a passage for supplying drilling fluid to the face of the bit, which carries a plurality of polycrystalline diamond preform cutting elements. The cutting elements are mounted on a single radially extending blade so that the bit is imbalanced and a resultant sideways force is applied to the bit as it rotates during drilling. The gauge of the bit body is provided with a low friction bearing pad which extends rearwardly of the blade and transmits the resultant sideways force to the sides of the bore hole. Since the bearing pad is low friction, it slides around the surface of the formation and any tendency for bit whirl to be initiated is reduced.

Abstract: A drill bit for drilling in the ground includes a pair of drilling cones having axes of rotation that converge near a drilling center of the bit. The cones each include a plurality of ridges or uninterrupted cutting edges. The cutting edges of each cone are separated by troughs. During rotation of the bit, the cutting edges of one cone are aligned so as to pass along the path traversed by the troughs of the opposite cone and vice versa. Drilling fluid jets are provided and flow connect with a drilling fluid supply to provide drilling fluid under pressure for cleaning and lubrication to the cones as well as to sweep away debris dislodged by the cutting action of the cones.

Abstract: A drill bit for use in drilling a well bore in accordance with this invention comprises a main drill body adapted to be rotated about a substantially vertically disposed axis of rotation and having therein a duct extending longitudinally along such axis, for supplying a drill fluid under pressure to the well bore. Three generally circular, rotatable cutting discs are mounted on the outside of the main drill body at equally spaced locations, with the cutting discs each having cutting elements disposed in a ring-shaped array. Each of the cutting discs has an axis of rotation disposed at an acute angle to the vertical centerline about which the main drill body rotates. Importantly, the axis of rotation of each cutting disc is slightly offset from the centerline of the main drill body, thus to cause the cutting discs to be positioned to be particularly effective and aggressive in cutting the well bore.

Abstract: The present invention is directed to a cutting head for use in a rotary drill bit in which the cutting head comprises a stem and a base integrally formed with the stem. The base has a first cutting surface defined by a frustrum of a cone or other shape and a second cutting surface defined a cone or other shape, wherein the first and second cutting surfaces are coaxial with the axis of the cutting head. The cutting head is adapted to be attached to a drill bit such that the axis of the cutting head is oriented at an angle with respect to the axis of the drill bit.

Abstract: A two-cone earth boring bit having non-opposite cones that minimize the tendency for off-center rotation or rough running. The bit is composed of two cones, each having a cantilevered bearing shaft with an axis extending inwardly and downwardly. A rotatable, generally conical cutter is mounted on each bearing shaft, each cutter having a conical gage surface to engage and define a borehole with a wall of select gage diameter. The axis of one cutter is skewed relative to the other to cause the conical gage surface of the two cones to engage the wall of the hole at points that are other than 180 degrees apart as compared to nonskewed cutters. These points are separated by a distance less than the selected gage diameter. A line between these points is separated from a line extending from one point through the rotatable axis on the bit by a selected angle. The body of the bit and/or stabilizers are separated from the wall of the hole by a distance less than the selected gage diameter.

Abstract: A drill bit for earth boring purposes includes a drill bit body which is rotatable about a drilling axis, a single cutting member mounted rotatably on the body and a counter-reaction member also mounted on the body. The counter-reaction member extends partially downwardly from the body and includes first and second outwardly exposed surfaces. The first surface has a greater surface area than the second surface and is at least partially formed with a circumferentially disposed curvature and a longitudinally disposed curvature with respect to the drilling axis so that it can closely conform to and contact the curvature of the bottom of the hole formed by the drill bit. The first surface of the counter-reaction member acts as a friction pad to counteract the torque effects of rotating the drill bit about the drilling axis and the cutting member engaging in the ground.

Abstract: An earth drilling bit that cuts concentric annular kerfs ahead of primary drilling means and thereby increases drilling rate. The bit includes a bit body having a lower end forming an annular cutter for cutting an outer annular kerf, an inner drill member positioned concentrically within the bit body having a lower end forming an annular cutter for cutting an inner annular kerf, a plurality of rotary drilling members attachedly arranged between the bit body and inner drill member positioned so lowermost cutting edges are above lowermost edges of the annular cutters of the bit body and inner drill member for removing material between the outer and inner annular kerfs, and plurality of drilling members attachedly arranged within the inner drill member positioned so lowermost cutting edges are above lowermost edges of the annular cutter of the inner drill member for removing material within the inner annular kerf.

Abstract: A rotary drilling device is disclosed of the type having a body connected to a rotary drive system for rotation about a primary axis in order to bore into the ground to form a cylindrical hole. The device has a rotary cutting member mounted on one side near the bottom of the body for rotation about an inclined axis of rotation which forms an angle with the primary axis of rotation. A counter-reaction member is disposed on the side of the body away from that carrying the cutting member and near its bottom. The counter-reaction member is constructed and positioned so as to be in contact with only the concave bottom of the hole and so that the maximum radial projection from the primary axis of rotation of any part of the counter-reaction member is less than the radius of the hole, with the highest point of the surface of contact between the counter-reaction member situated below a line defined by the intersection between the concave bottom of the hole and its cylindrical side wall.

Abstract: A drill bit has a plurality of roller cutters mounted on a front face of the drill bit. The roller cutters are mounted in pairs which are equidistantly spaced from an axis of rotation of the drill bit. Each roller cutter is rotatably mounted in a saddle affixed on the front face. The roller cutters are reversibly mounted in their saddles. Each roller cutter includes a plurality of circumferentially extending cutting structures spaced apart along an axis of rotation of the roller cutter. The cutting structures are arranged non-symmetrically relative to a center plane through the roller cutter so that when a roller cutter is reversed, the location of kerfs cut by the roller cutter change.

Abstract: The invention relates to a drill bit which includes a drive arrangement having two opposed drive shafts which are transverse to the drill rod axis, mechanism for driving the shafts and a rock comminuting cutter which is eccentrically mounted on each of the shafts.

Abstract: A rotary drilling device is disclosed of the type having a body connected to a rotary drive system for rotation about a primary axis in order to bore into the ground to form a cylindrical hole. The device has a rotary cutting member mounted on one side near the bottom of the body for rotation about an inclined axis of rotation which forms an angle with the primary axis of rotation. A counter-reaction member is disposed on the side of the body away from that carrying the cutting member and near its bottom. The counter-reaction member is constructed and positioned so as to be in contact with only the concave bottom of the hole and so that the maximum radial projection from the primary axis of rotation of any part of the counter-reaction member is less than the radius of the hole, with the highest point of the surface of contact between the counter-reaction member situated below a line defined by the intersection between the concave bottom of the hole and its cylindrical side wall.

Abstract: Improvement in the drilling of vertical bore holes is achieved by an asymmetrical rotary cone bit having a substantially cylindrical body with a shank formed on the body and extending therefrom along a vertical axis for connection to a drill string. Projecting from the cylindrical body are three journal pins, which pins extend from the end of the body opposite from the shank. These three journal pins are circumferentially displaced such that the rotational axis of the first and second pins are displaced more than 120 degrees and less than 180 degrees. The axis of the third journal pin is circumferentially displaced equidistant from the axis of the other two journal pins. Journaled on the first and second journal pins are first and second roller cutter cones having substantially the same based diameter. Each of these cutter cones has cutting teeth extending from the surface thereof and includes a row of gage cutting teeth.

Abstract: A drill bit for use with a reciprocating device, wherein the bit is in the form of a rotatable corrugated frusto-conical roller, supported by a U-shaped member, attached to a mounting post. The corrugations are the cutting edges of the bit.

Abstract: The present invention relates to a roller cutter to be mounted on a rock boring head via a journal and a saddle. The journal has two ends that are supposed to be fixed to a conventional saddle. The journal is surrounded by a rotatably carried roller body comprising rows of circumferentially extending cutting means. The rotational axis of the roller cutter inclines an angle .phi..sub.1 with respect to the center line of the journal so that a true rolling movement may be obtained between the roller cutter and the rock surface.

Abstract: A rotatable cutter head for a pit boring machine used in reverse circulation drilling. The cutter head has cutter arrays including rotary cutters and drag cutters and disposed radially and circumferentially spaced positions on the cutter head, the drag cutters having the cutting ends lying generally in a conical plane having the axis coaxial with the axis of rotation of the cutter head. The rotary cutters each have cutting teeth around the circumference thereof and each tooth has an inclined side face lying in a further conical plane the central axis of which is coaxial with the axis of rotation of the rotary cutter, the inclined side face of each tooth facing generally along the inclination of the conical plane in which the cutting ends of the drag cutters lie, and the tip of each cutting tooth of each rotary cutter projecting beyond the plane in which the cutting ends of the drag cutters lie.

Abstract: A milling tool for forming recesses, such as an undercut in a borehole, in masonry, concrete and similar material structures includes a tool shaft with a bearing pin extending outwardly from one end of the shaft and with the axis of the pin offset eccentrically to the axis of the tool shaft. A freely rotatable annular milling head is positioned on and encircles the bearing pin. The outside surface of the milling head has cutting edge members.

Abstract: A tri-cone rotary rock bit having true rolling conical cutters of different cone angle and with each cutter having a plurality of intermediate annular rows of cutting projections for disintegrating the borehole bottom. Such projections in the intermediate rows being true-rolling about a bottom distinct from the bottom cut by the projections on the remaining intermediate annular rows of the cutting projections of each cone are also at distinct separate distances from the center of rotation of the bit to produce a borehole bottom profile having concentric rows of crests and valleys.

Abstract: An oil well drilling bit is disclosed of the type utilizing hard metal inserts in the rolling cutters wherein each row of inserts on each cutter is located thereon in a sinusoidal or varying pattern rather than the strictly circumferential pattern of the prior art.

Abstract: A roller bit for use with a drill string, having at least two cutters which are generally conically shaped; each cutter includes one or more teeth in inclined planes across a conical surface. The bit is attached to the drill string with the axis of rotation of the cutter angled with respect to the longitudinal axis of the drill string. The teeth on each cutter are arranged for maximum cuttings size and penetration rate.

Abstract: A rock boring bit assembly which includes a body configured for engagement with associated driving mechanism. At least one roller cutter is rotatably mounted on the body. The roller cutter includes a plurality of cutting member disposed about the entire face or surface thereof in generally upstanding relationship. The cutting members are arrayed over the roller cutter surface with no channel between adjacent arrays of cutting members. The cutters have generally rectilinear edges and each of the edges is disposed in substantially oblique relationship to a plurality of other rectilinear edges of other cutting members disposed proximate thereto.

Abstract: Apparatus for boring holes in rock comprising a boring head rotatable about an axis of advance and a multiplicity of cutters mounted on the head, a plurality of which each comprises a cutter body rotatable about a cutter axis and cutting tooth means forming a helical path about the cutter axis.

Abstract: A bit connectible from the lower end of a rotatably powered drill stem for enlarging a preformed pilot hole includes a cutter carrier frame on which are mounted a plurality of roller cutters having peripheral cutting edges which sweep concentric circles upon rotation of the raise drilling bit. The circles swept by the cutters collectively define a generally dome-shaped cutting profile of constantly changing curvature which forms a segment of a spiral curve so that as the cutting profile extends radially outwardly from the drill stem, its curvature progressively decreases. The rotating cutter carrier frame structure drives a flywheel assembly at increased speed through the intermediacy of a step-up drive system composed of two planetary gear drives coupled in tandem.

Abstract: A hybrid rock bit is disclosed wherein a pair of opposing extended nozzle drag bit legs are positioned adjacent a pair of opposed tungsten carbide roller cones. The extended nozzle face nearest the hole bottom has a multiplicity of diamond inserts mounted therein. The diamond inserts are strategically positioned to remove the ridges between the kerf rows in the hole bottom formed by the inserts in the roller cones.

Abstract: An earth boring drill bit, particularly for large diameter shafts, has a cutter assembly with improved bearing and seal arrangement and an improved cutting insert arrangement. A cutter assembly has an axle with an enlarged central portion and reduced portions on both sides. A cutter sleeve is carried on bearings by the central portion of the axle. An annular member with a central bore is secured to each side of the cutter sleeve. A metal face seal is secured between the reduced portion and the central bore on each side. The cutter contains rows of hard metal inserts secured in holes in the exterior. To reduce tracking, the inserts within a row are separable into groups with varied pitch within each group. The groups cycle with two groups having a gradual increase in pitch and two groups having decreasing pitch.

Abstract: A bore head for reaming a pre-drilled hole in raise boring or for similar earth cutting operations comprising at least two sets of roller cutters. The roller cutters in the same set of cutters have the same number of rows of cutting means. The roller cutters are mounted in pairs on each side of the rotational axis of the bore head. During rotation of the bore head the cutting means move along concentric circles. In order to change the distance between two consecutive circles a roller cutter in one of the pairs of cutters is replaced by a roller cutter of the other set of cutters.

Abstract: An earth boring drill bit for large diameter shafts has an improved cutter arrangement. The drill bit has a cutter support member with a number of cutters mounted to it for disintegrating the earth formation face. At least one inner cutter is mounted near the center for cutting the center area. A number of gage cutters are mounted at the periphery to cut the gage area of the shaft. A number of intermediate cutters are spaced between the inner and gage cutters. Each intermediate cutter overlaps one-half of its width with an adjacent intermediate cutter.

Abstract: An earth boring system is provided with universal cutter means for boring in all types of formations. The cutter means is mounted on a drill bit body or cutterhead with said bit or cutterhead functioning to form a hole in the earth formations. At least two annular rows of major inserts are mounted in the cutter means. The major inserts project from the surface of the cutter means a substantial distance for forming circular kerfs in the earth formations being bored. An annular row of minor inserts are mounted in the cutter means between the two annular rows of major inserts. The minor inserts project from the surface of the cutter means a distance that is substantially less than the distance the major inserts project from the surface of the cutter means.

Abstract: A rotary rock bit is constructed having rolling cutter members for forming a borehole in the earth. Each rolling cutter member includes an annular row of cutting elements for cutting portions of the borehole. The cutting elements comprise cutting teeth or cutting inserts. Varied pitches are provided between the inserts/teeth. The pitches between pairs of inserts/teeth are varied so that the pitches between no two pairs of inserts/teeth in a row or group are the same. Since no two pairs of inserts/teeth have the same pitch, the probability of tracking will be remote. This increases the rate at which the bit penetrates the formation and generally decreases the probability of insert/tooth breakage therein. The present invention reduces or eliminates tracking and stumbling encountered in prior art earth boring bits.

Abstract: A specially shaped insert of the type used for the cutter teeth of rock bits used in drilling soft and medium formations of the earth. The insert is generally chisel-shaped with flanks converging to a crest. The flanks are asymmetrical with respect to each other. The leading flank is scoop-shaped and the trailing flank is rounded outwardly.

Abstract: A three cone rock bit comprises legs and freely rotating cutters mounted on the same. The angle .alpha. between the projections of the rotational axes of two adjacent cutters on a plane perpendicular to the axis of the bit is more than 120.degree. but less than 170.degree.. A flow nipple to supply drilling fluid is provided in the bit, the outlet thereof being positioned between said two cutters.

Abstract: The body of the bit includes an axis of rotation, an upper end connectable with the drill string for rotating the bit and three downwardly projecting arms. Each of the arms includes an inwardly and downwardly inclined shaft defining an axis of cutter rotation with all of the axes intersecting at substantially a common point. First, second and third conical cutter members are journaled on a respective one of said shafts. Each cutter member includes a nose and a base with the base being oriented generally toward the wall of the well bore. A plurality of outwardly projecting, circumferentially-spaced inserts are located in annular rows in each cutter member for engaging the bottom of the well bore.

Abstract: Improved cutter elements for drill bits of the type having two to four conical-shaped cutters mounted in a supporting body for rotation about their respective axes with their apices inclined downwardly-inwardly toward the axis of rotation of the body; the cutter elements are spaced apart from one another both axially and circumferentially of the substantially conical exterior of each conical-shaped cutter and, usually, disposed in spaced circumferential rows, each cutter element including a pair of interacting chisel or wedge-shaped teeth intersecting each other--preferably at their medial portions in perpendicular relationship--coextensive from crest to root and having their respective crests extending approximately radially of the axis of rotation of said cutter and generally circumferentially of said cutter axis; the circumferentially--oriented teeth have coextensive cutting edges at their ends and are adapted to cut through ridges created in the formation by the radially-oriented teeth and laterally displ

Abstract: In boring apparatus of the type having cutters mounted for rotation about respective cutter axes in a frame which is in turn rotatable about a frame axis, each cutter having a body carrying teeth which in operation sweep a surface which is oblique to the axis of advance of the apparatus, that improvement wherein each cutter has selected tooth regions, preferably of alternating high and low tooth densities, spaced along the respective cutter axis, the tooth regions of the cutters are arranged in an ordered cycle progressing along the frame axis, and regions adjacent each other in the cycle are on different cutters and overlap each other along the frame axis.

Abstract: A drill bit has a plurality of roller cutters mounted on a front face of the drill bit. The roller cutters are mounted in pairs which are equidistantly spaced from an axis of rotation of the drill bit. Each roller cutter is rotatably mounted in a saddle affixed on the front face. The roller cutters are reversibly mounted in their saddles. Each roller cutter includes a plurality of circumferentially extending cutting structures spaced apart along an axis of rotation of the roller cutter. The cutting structures are arranged non-symmetrically relative to a center plane through the roller cutter so that when a roller cutter is reversed, the location of kerfs cut by the roller cutter change.

Abstract: A two-cone earth boring bit having non-opposite cones that minimize the tendency for off-center rotation or rough running. The bit is composed of two cones, each having a cantilevered bearing shaft with an axis extending inwardly and downwardly. A rotatable, generally conical cutter is mounted on each bearing shaft, each cutter having a conical gage surface to engage and define a borehole with a wall of .[.select.]. .Iadd.ed .Iaddend.select gage diameter. The axis of one cutter is skewed relative to the other to cause the conical gauge surface of the two cones to engage the wall of the hole at points that are other than 180 degrees apart as compared to nonskewed cutters. These points are separated by a distance less than the selected gage diameter. A line between these points is separated from a line extending from one point through the .[.rotatable.]. .Iadd.rotational .Iaddend.axis on the bit by a selected angle.