Abstract: A method for use in designing rotary drill bits comprises determining locations in which cutters are to be provided, determining likely wear rates for cutters positioned at those locations, and using the likely wear rates to chose between relatively high and relatively low wear rate cutters for each location. The cutters all have substantially the same impact toughness.

Abstract: An earth boring bit for boring a hole having a predetermined depth into the earth. The earth boring bit includes a cylindrical drum for being mounted for rotation on the end of a boom of a mobile machine and connected to and rotated by a power supply mounted on the boom. The drum includes an exterior for defining the diameter of the hole being bored and an interior adapted for receiving upturned earth therein as the hole is being bored. A plate is mounted in the drum adjacent a lower end thereof for movement between a closed position for cooperating with the interior of the drum for retaining the upturned earth therein and an open position for dispensing the upturned earth out of the interior of the drum at a predetermined location away from the hole being bored. At least one cutting member is carried on the plate for cutting the earth in a progressive slice and directing the earth into the drum, thereby boring the hole into the earth.

Abstract: A PDC-equipped rotary drag bit especially suitable for directional drilling. Cutter chamfer size and backrake angle, as well as cutter backrake, may be varied along the bit profile between the center of the bit and the gage to provide a less aggressive center and more aggressive outer region on the bit face, to enhance stability while maintaining side cutting capability, as well as providing a high rate of penetration under relatively high weight on bit.

Abstract: A torque limiting device that allows a drill string to rotate relative to the cutting structure of the bit when a predetermined torque is applied between the cutting structure of the drill bit and the drill string. The torque limiting device utilizes a retaining member which restricts rotational movement of a first component of the torque limiting device relative to a second component. When a sufficient torque load is placed on the cutting structure of the drill bit, the retaining member allows rotational movement of the first component relative to the second component and allows the drill string to continue to rotate relative to the cutting structure of the bit until the torque is sufficiently reduced. The torque limiting device may be an integral part of a drill bit, may be a separate device attached between the drill string and the drill bit or between the drill string and a downhole motor, or may be part of a near-bit sub or incorporated in a downhole motor.

Abstract: A new hardfacing composition is disclosed. In addition, a pulsed plasma transferred arc method for depositing hardfacing material with a higher content of carbide and lower dilution by a substrate metal is disclosed. The disclosed method produces a hardfacing coating which has a strong metallurgical bond to the substrate metal. The method includesthe following steps: (1) establishing a transferred plasma arc between an electrode and an area of a work piece, (2) optionally preheating the work piece to at least 250.degree. F., (3) forming a plasma column of inert gas in the arc by passing an electrical current between the electrode and the work piece, (4) feeding a stream of hardfacing material in powder form into the plasma column, and (5) pulsing the current between a pre-selected high pulse current value and low pulse current value while feeding the powdered hardfacing material.

Abstract: A roller cone or drag-type drill bit for use in drilling subsurface formations, especially useful for directional drilling, has a bit body with a shank portion for connection to a drill string, and a crown portion. Breaker slots are formed in the bit body at or immediately adjacent to the intersection of the crown portion and the shank portion. This location of the breaker slots allows the drill bit to be relatively shorter than comparable prior art bits with the breaker slots formed in the shank portion. The shorter length permits the present drill bit to be more easily steered in directional drilling applications.

Abstract: The invention relates to a tool for drilling oil, gas or geothermic wells. The tool includes two main members, a hollow shaft (1) and a blind tool body (2) more elongate than conventional tool bodies; the two main members are spherically connected to each other by means of a ball joint (4,5). The ball joint is located at the very bottom of the blind portion of the tool body which carries a stabilizer (19) at the other end. The tool is also provided, between the hollow shaft and the tool body, with an appropriate transmission system (6, 7, 8, 9, 11), which is spaced apart from the ball joint and situated between the latter and the stabilizer. The essential advantage of the tool lies in the relative position of the ball joint and the stabilizer, the positioning conferring on the tool a favorable dynamic behavior, without risk of buttressing. Field of application: drilling of oil wells, gas wells and geothermic wells.

Abstract: A mechanism (22) for supporting an earthworking tool from a vehicle such as a front end-loader (21) includes: (i) a primary support structure (23) adapted to be pivotally attached, in a readily releasable manner, about a generally upright, slewing axis (24), to a conventionally-provided elevating linkage mechanism (25) of a vehicle; (ii) power driver (26,27) to effect controlled slewing of the primary support structure (23) about its slewing axis (24); (iii) a secondary support structure (28) rotatably mounted about a generally forwardly directed axis (29) on the primary support structure (23); (iv) power driver (30) to effect controlled rotation of the secondary support structure with respect to the primary support structure; (v) tool support (32) pivotally mounted on the secondary support structure (28); and (vi) driver (33) to pivot the tool support with respect to the secondary support structure.

Abstract: A quick detach bit apparatus includes a wear sleeve having a chuck threaded thereinto. A bit is mounted within the chuck. The bit and chuck are interconnected by mating, axially extending splines and grooves. The chuck includes a resiliently mounted segment urged into engagement with the bit. A quick release tool is accommodated in a passage between the bit and chuck. The tool is inserted into the passage and has a thickness sufficient to urge the segment out of engagement with the bit so that the bit is removed from the chuck.

Abstract: A bucket auger for excavating holes for planting trees is disclosed which includes a trapezoidal cutting frame having teeth secured to the side and bottom. A central vertical shaft adapted to connect to a rotational drive mechanism is secured through upper and lower members of the frame. Two half frusto conical bucket members are pivotally suspended from the upper cross member of the cutting frame by arms such that the weight of the bucket members plus the weight of earth contained within force the bucket to remain closed during lifting of the bucket auger out of the excavation. Lifting flanges are provided for attaching lifting/opening cables to force the two bucket members open to release the earth contained therein.

Abstract: There is provided a rock bit comprising a bit body having a dome and a plurality of legs, each with a journal pin. A cutter cone is mounted on each journal pin with a cone seal between the journal pin and cutter cone. A sacrificial anode is attached to the dome of the bit body having a shape for diverting flow of drilling mud around the cutter cones. Preferred shapes of the sacrificial anode include inverted cones and tetrahedrons. The sacrificial anode prevents cone seal failures caused by corrosion of the bit body adjacent the cone seals.

Abstract: The device described herein comprises a bit for drilling oil wells, water wells, foundation sockets for bridges and buildings, air and utility shafts for mines, etc., which bit comprises an inner core or mandrel and an outer shell or exterior sleeve, which shell or sleeve is replaceable when worn. The inner core resembles in many features, the standard type of bit in present use in that the means for holding, supporting and driving the bit are similar to those in present practice, and has appropriate openings and means for blowing air and/or liquid through the bit to blast away rock dust and cuttings. The novelty of the new device resides in having a lower annular end of the core preferably slightly tapered inwardly toward the extreme end, and having fitted over this annular section a sleeve or shell whose inner surface is preferably also slightly tapered, corresponding in size and shape to and in close contact with the said annular section of the core thereby providing a tight fit.