Abstract: A drill bit having cutting elements disposed on a roller cone surface in a non-linear pattern, wherein at least one of the cutting elements is asymmetrical to its axis of orientation. Also, a method for selecting and adjusting a cutting element orientation based on crater profile geometry which results in increased bottom hole coverage.

Abstract: A cutter element for a drill bit includes a leading cutting surface and a trailing cutting surface. The leading surface includes a top surface and a front surface that meet in a radiused intersection forming a forward-facing, non-linear crest of non-uniform radius. The radius of the crest is smallest at the forward-most portion, and greater at each end. The crest has its largest radius at a location between its forward-most portion and one of its ends. The cutter element may be employed in the corner cutting portion of a rolling cone cutter in a drill bit, the cutter element being positioned such that the forward-most portion of the crest first engages the formation material, with the crest end having the largest radius being closest to the pin end of the bit.

Abstract: A method for designing a roller cone drill bit having a plurality of cutting elements in a row. The method includes defining a pitch pattern for the plurality of cutting elements such that a first group of adjacent cutting elements are arranged in a first pitch and a second group of adjacent cutting elements are arranged in a second pitch in the row; evaluating the pitch pattern of the plurality of cutting elements in the row; and modifying at least one of the plurality of cutting elements, based on the evaluating the pitch pattern of the plurality of cutting elements.

Abstract: A drill bit for drilling through earthen formations and forming a borehole. In an embodiment, the bit comprises a bit body having a bit axis. In addition, the bit comprises a plurality of cone cutters, each of the cone cutters being mounted on the bit body and adapted for rotation about a different cone axis. Further, at least one cone cutter on the bit comprises an array of cutter elements mounted in a band. Still further, the cutter elements in the array are mounted in a plurality of differing radial positions relative to the bit axis.

Abstract: A rolling cone drill bit including multiple cones with regions of intermeshing and non-intermeshing cutter elements. In the non-intermeshed regions, an array of cutter elements is disposed about the cone surface in a non-circumferential arrangement with the cutter elements being mounted at differing radial distances from the bit axis. This non-circumferential arrangement, which may be a spiral, multiple spirals, other patterns of offset cutter elements, or a random arrangement, provides a composite cutting profile having substantial width and bottomhole coverage and is free of ridge-producing voids. In certain embodiments, the composite cutting profiles of the arrays at least partially overlap, and may be arranged to cover a portion of or the entire non-intermeshed region on the cones.

Abstract: A roller cone drill bit and a method for designing thereof. The roller cone drill bit includes a bit body configured to be coupled to a drill string and a journal depending from the bit body. A split roller cone is rotatably attached to the journal. The split roller cone includes an upper section and a lower section. The upper section has a plurality of cutting elements disposed at selected positions thereon. The lower section has a plurality of cutting elements disposed at selected positions thereon. The lower section is able to rotate independently of the upper section.

Abstract: A novel rolling cone rock bit includes a plurality of PDC or other cutters mounted to the leg of the drill bit and positioned to cut the troublesome corner of the bottomhole. The plurality of cutters may be the primary cutting component at gage diameter, or may be redundant to gage teeth on a rolling cutter that cut to gage diameter. Consequently, the occurrence of undergage drilling from the wear and failure of the gage row on a rolling cutter is lessened. Another inventive feature is the inclusion of a mud ramp that creates a large junk slot from the borehole bottom up the drill bit. The resulting pumping action of the drill bit ramp speeds up the removal of chips or drilling cuttings from the bottom of the borehole, reduces the level of hydrostatic pressure at the bottom of the borehole and minimizes the wearing effect of cone inserts regrinding damaging drill cuttings.

Abstract: A surgical apparatus includes a surgical device, configured to be manipulated by a user to perform a procedure on a patient, and a computer system. The computer system is programmed to implement control parameters for controlling the surgical device to provide at least one of haptic guidance to the user and a limit on user manipulation of the surgical device, based on a relationship between an anatomy of the patient and at least one of a position, an orientation, a velocity, and an acceleration of a portion of the surgical device, and to adjust the control parameters in response to movement of the anatomy during the procedure.

Abstract: A novel rolling cone rock bit includes a plurality of PDC or other cutters mounted to the leg of the drill bit and positioned to cut the troublesome corner of the bottomhole. The plurality of cutters may be the primary cutting component at gage diameter, or may be redundant to gage teeth on a rolling cutter that cut to gage diameter. Consequently, the occurrence of undergage drilling from the wear and failure of the gage row on a rolling cutter is lessened. Another inventive feature is the inclusion of a mud ramp that creates a large junk slot from the borehole bottom up the drill bit. The resulting pumping action of the drill bit ramp speeds up the removal of chips or drilling cuttings from the bottom of the borehole, reduces the level of hydrostatic pressure at the bottom of the borehole and minimizes the wearing effect of cone inserts regrinding damaging drill cuttings.

Abstract: A method for forecasting performance of a drill bit, that includes obtaining a performance model for the drill bit, using a plurality of bit run records of the drill bit, wherein the obtaining is performed with a multivariate regression, and inputting a set of drilling parameters to the performance model to obtain the performance of the drill bit.

Abstract: The cutter element includes a rounded apex offset from the center line of the insert and having a relatively broad and blunt front face and a narrower, more rounded rear face. The cutter element may be disposed in the outermost inner row of a rolling cone cutter of a bit with the broader front face facing the borehole side wall so as to resist off center wear and resultant bit whirl. When placed in inner rows and oriented with the broader and flatter front face being the first portion of the cutting surface to engage the borehole, enhancements in bit durability may be achieved, particularly when drilling through formations of multiple hardness.

Abstract: A method for designing a roller cone drill bit having a plurality of cutting elements in a row. The method includes defining a pitch pattern for the plurality of cutting elements such that a first group of adjacent cutting elements are arranged in a first pitch and a second group of adjacent cutting elements are arranged in a second pitch in the row; evaluating the pitch pattern of the plurality of cutting elements in the row; and modifying at least one of the plurality of cutting elements, based on the evaluating the pitch pattern of the plurality of cutting elements.

Abstract: A method of forming milled teeth on a roller cone of a milled tooth roller cone rock bit includes shaping a crest of a chisel shaped milled tooth on the roller cone. The crest is shaped such that the crest has a convex profile from one corner to an opposite corner of the crest. Such a crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution. Further, the forming includes radiusing each of the corners at the ends of the crest of the chisel shaped milled tooth.

Abstract: Provided are methods, data communication apparatus and computer programs for managing communications between a remote communication manager and a set of communications managers in an associated group. The group of communication managers have shared access to resources which enable any communication manager in the group to recover from failures experienced by another communication manager in the group. In particular, recovery of failed inbound and outbound channels is achieved with the advantage of improved availability of data transmissions. Preferably, the recovery uses synchronization information to ensure that data is recovered to a consistent state to that channel recovery is achieved without loss of data integrity.

Abstract: The invention is a drill bit that has a bit body, at least one roller cone attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on the at least one roller cone. At least one bit design parameter is selected so that the cutting elements wear in a selected manner when drilling an earth formation. The invention is also a method for designing a drill bit that has at least one roller cone and a plurality of cutting elements. The method includes several steps, beginning with selecting initial bit design parameters. The drill bit is then simulated drilling at least one selected earth formation. The wear induced change in the cutting element geometry is determined and the simulated bit is adjusted to reflect the wear. The selecting, simulating, determining, and adjusting are repeated and at least one bit design parameter of the drill bit is adjusted until at least one performance parameter of the drill bit is optimized.

Abstract: A method of forming milled teeth on a roller cone of a milled tooth roller cone rock bit includes shaping a crest of a chisel shaped milled tooth on the roller cone. The crest is shaped such that the crest has a convex profile from one corner to an opposite corner of the crest. Such a crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution. Further, the forming includes radiusing each of the corners at the ends of the crest of the chisel shaped milled tooth.

Abstract: Disclosed are a variety of arcuate-shaped inserts for drill bits, and in particular, for placement in rolling cone cutters of drill bits. The arcuate inserts include 360° or ring-shaped inserts, as well as inserts of smaller arcuate length. The arcuate inserts are suitable for use in all surfaces of the rolling cone cutter, and in other locations in drill bits, and may have specialized cutting surfaces and material enhancements to enhance their cutting duty performance. Certain arcuate inserts may include stress relieving discontinuities such that, upon assembly into the cone or during drilling, the arcuate inserts may fragment in a controlled and predicted manner into shorter arcuate lengths.

Abstract: A method for designing a drill bit that involves simulating a drill bit having cutting elements disposed thereon is provided.

Abstract: A method for designing a drill bit that has at least one roller cone and a plurality of cutting elements, including selecting initial bit design parameters. Drilling simulations are then used to determine wear, and the simulated drill bit is changed to reflect the determined wear. Then, at least one design parameter is adjusted. The simulation, determination, change of the simulated drill bit, and adjustment may be repeated until at least one performance parameter of the drill bit is optimized. A drill bit can be designed using such a method.

Abstract: A method for evaluating a cutting arrangement for a drill bit includes selecting a cutting element arrangement for the drill bit and calculating a score for the cutting arrangement. This method may be used to evaluate the cutting efficiency of various drill bit designs. In one example, this method is used to calculate a score for an arrangement based on a comparison of an expected bottomhole pattern for the arrangement with a preferred bottomhole pattern. The use of this method has lead to roller cone drill bit designs that exhibit reduce tracking over prior art bits.