Abstract: A two-cone drill bit that exhibits improved stability. In one embodiment, the two-cone drill bit has a first and a second roller cone arranged to have a cone separation angle between about 145 degrees and about 166 degrees. In some embodiments, the two-cone drill bit has a plurality of cutting elements arranged on the roller cones such that a bottom hole coverage greater than about 17 percent is achieved per revolution of the two-cone drill bit.

Abstract: This invention relates to a single cone bit with offset axis and composite cones for oil and gas drilling, mining and other subterranean drilling operations. The bit consists of a head body and a cone. The cone section has a shape of composite cones. The outer circumference of the cone is composed of from back face of the cone to top of the cone an extended gage surface, an outer cone surface and a main cone surface. A plurality of cutting elements is mounted onto each cone surface. A head journal at lower end of the head body is for rotatablely connection with the cone. Between the axis of head journal and the axis of the bit, there is an offset value d along rotating direction of the cone. A gage pad is arranged on head body at a location opposite to the offset direction of the head journal. The gage pad is fitted with inserts or hardfaced with wear resistant alloy to prevent bit from whirling and prevent head body from being worn out and to ensure gage protection.

Abstract: A drilling device for producing undercut holes. The drilling device includes a drilling tool having an axis of rotation and a cutting portion arranged such that the cutting portion drills a hole with a longitudinal axis that is radially offset with respect to said axis of rotation and a centering device operable to apply a lateral force to said drilling tool for moving said axis of rotation towards said longitudinal axis to cause said cutting portion to form an undercut in a said hole.

Abstract: Excavator drum for the production of vertical trenches, including a cylindrical shell (22) mounted so sa to rotate about its axis of revolution and a plurality of excavating tools (28, 30) mounted on the external face of the shell. The tools include a plurality of first rollers (36) equipped with cutting elements (38) mounted so as to rotate about axes, the mid-plane of the rollers substantially merging with the mid-plane (P-P?) of the shell, and the length of which is less the an the length of the shell; and a plurality of pairs of second rollers (50, 52) equipped with cutting elements, the rollers of the same pair being mounted so as to rotate about cantilever axles (54, 56) each roller having a length at least equal to the distance that separates one end a first roller from the corresponding end of the shell, the casing of the external end of the second rollers being at least in the plane containing one end (32, 34) of the shell.

Abstract: The invention is directed to a roller cone drill for drilling earth formations and a method of using the same. The drill bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The drill bit further includes a plurality of cutting elements disposed on each of the roller cones, an offset of at least about 0.375 inches; and a journal angle less than about thirty degrees. In one embodiment, the drill bit includes three roller cones. In another embodiment, the cutting elements of the bit are arranged on each cone so that cutting elements on adjacent cones intermesh between the cones.

Abstract: The invention relates to a roller cone drill bit for drilling earth formations. The drill bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. Each roller cone of the bit includes a truncated apex and a side surface. The drill bit further includes a plurality of cutting elements disposed on the side surface of each cone. The cutting elements on at least one cone are arranged such that at least one cutting element on that cone extends past an axis of rotation of the bit body as the bit is rotated. In one embodiment, the drill bit includes three cones and the cutting elements are arranged on the cones so that cutting elements on adjacent cones intermesh between the cones.

Abstract: A boring head is provided for use in mounting to a drill pipe of a drilling rig for enlarging a pilot bore in horizontal boring operations. The boring head has an axial member positioned along a central axis of the boring head for connecting the boring head to the drill pipe of the drilling rig. A plurality of flanges extend radially from the axial member, and a flange support frame is provided for structurally interconnecting and supporting the flanges on the axial member. A plurality of cutting cones are mounted to the boring head. In particular, each of the cutting cones has a cone axis, each of the cutting cones is mounted to one of the flanges such that its cone axis extends at an acute angle ranging from zero degrees up to about 45 degrees relative to the central axis; each of the cutting cones is mounted for independent rotation about its cone axis; and each of the cutting cones has a plurality of independently rotatable cutting bits mounted thereto.

Abstract: A drill bit for use in drilling a well bore 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. At least one 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. The axis of rotation of each cutting disc is slightly offset laterally in a rearward direction from the centerline of the main drill body, thus to cause the entire bit to be placed in a non-equilibrium position with the rotation of the main body enabling the cutting disc to be positioned to be particularly effective and aggressive in cutting the well bore.

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: 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 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 mechanism is disclosed for rock bits whereby cutting elements, rotatably mounted to fixtures with journals, are constantly forced to rotate or precess by the interaction of the earth formation and the cutter. The cutters are fixed in skewed or offset positions on a cutting face of a rotary drill bit head. These cutting elements act as drag or shear cutters when they are operated in an earth formation.

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.