Abstract: An elongate cutter for a drag-type drill bit includes a stud defining one end thereof and a cutting formation comprising a cutting face generally adjacent the other end. Length extends from one end to the other, depth extends generally transverse to the cutting face as well as transverse to the length, and width extends transverse to both length and depth. The stud has a cross section transverse to its length such that the cross section cannot be circumscribed by a reference circle whose diameter is equal to the maximum width of the cross section. The cross section also has an assumed section modulus, in the direction of depth, greater than that of the reference circle. The leading side of the cutter comprises a first planar zone adjacent the one end and a second planar zone adjacent the other end, and on which the cutting formation is carried. The maximum lateral dimension of the leading side is generally greater than or equal to the maximum width of the cutter.

Abstract: A drill bit for drilling deep holes in subsurface formations comprises a bit body having a generally hemispherical leading face and a gauge region, and two blades each extending spirally outwardly across the leading face of the bit body away from the axis of rotation, a cavity of substantial peripheral and axial extent being formed in the bit body on the forward side of each blade, and communicating with an associated exit channel in the gauge region. A plurality of cutting elements are mounted along each blade, the cutting elements being mounted closely adjacent one another side-by-side along the blade so that their cutting edges together form a single long cutting edge without substantial discontinuities. A passage in the bit body supplies drilling fluid to nozzles in the cavities for cooling and cleaning the cutting elements, fluid from the nozzles sweeping past the cutting elements and out through the exit channels.

Abstract: A drag type rotary bit (10) having a plurality of arcuate blades (24A-24E) each having a row of cutting elements (36A-36G) thereon. The cutting elements (36A-36G) are arranged on the arcuate blades (24A-24E) with around one-half of the length of the arcuate blades (24A-24B) being positioned adjacent the outer periphery (20) of the bit body (12) to provide a relatively long length mounting area or the cutting elements (36D-36G) at the gage (20). Deep grooves (26) are provided adjacent each of the blades (24A-24E) and provide a relatively large passage for the outwardly flow of drilling fluid and entrained cuttings.

Abstract: A triple cone drill bit (10, 10A) comprising a plurality of conical roller cutters (16, 16A) having hard metal cutting elements thereon and being so positioned relative to each other that their rotational axes are offset from the rotational axis of the drill bit (10, 10A), and a drilling fluid nozzle system for directing a pressurized fluid stream (76, 76A) across certain of the cutting elements and thereafter against the formation generally at the bottom of the well bore so that when the drill bit (10, 10A) is used in its most advantageous areas, such as the soft, medium-soft and plastic formations, the nozzle system prevents "balling up" of the cutters and greatly increases the drilling efficiency of the bit. In one embodiment (FIGS. 15-20) the drill bit body (12A) has vertically extending recessed portions (21A) formed at the junctures (19A) of the lugs (15A) to provide flow passageways for the upward flow of drilling fluid and entrained cuttings.

Abstract: A rotary drill bit for use in drilling or coring deep holes in subsurface formations comprises a bit body having a leading face and a gauge region, cutting elements mounted at the leading face of the bit body, and a passage in the bit body communicating with nozzles in the leading face of the bit body for supplying drilling fluid to the face for cooling and cleaning the cutting elements. Certain of the cutting elements each comprise a preform cutting element having a superhard front cutting face providing a cutting edge, and others of the cutting elements each comprise particles of hard material embedded in a front layer of a less hard material to form a cutting layer having a cutting edge.

Abstract: A seal assembly for a roller cutter bit mounted in an annular cavity between a roller cutter and a journal. A mechanical spring on the roller cutter urges in an axial direction sealing faces on respective rigid seals into sealing engagement with each other against the bias of an opposed to elastomeric seal. Even upon permanent or compression set of elastomeric seal, the sealing force is maintained by the mechanical seal against the sealing faces on the rigid annular rings.

Abstract: A drag type rotary drill bit (10) having mounted on its lower face (22) a rigid integral holder (30) for a plurality of polycrystalline diamond compact (PDC) cutting elements (42) secured to a planar face (60) of the holder (30). An upper projecting tapered end portion (71) of the holder (30) defines tapered surfaces (72, 73) with the lower tapered surface (72) extending at a relatively large clearance angle (B) to provide a relatively small wear flat surface on the holder (30).

Abstract: A drag type rotary bit (10) having polycrystaline diamond compact (PDC) cutting elements arranged in a plurality of rows extending from the center of the bit body (12) to the outer peripheral surface (20) thereof. A fluid discharge nozzle (38A-38F) is provided for each row of cutting elements (36A-36G) and has a fluid discharge stream (62) directed downwardly against the bore hole bottom (66) and opposite the direction of rotation of the bit (10) ahead of the associated row of cutting elements (36A-36G) for flowing against the cutting faces (53) of the cutting elements (36A-36G) after impingement of the bore hole bottom (66).

Abstract: A method of manufacturing by a powder metallurgy process a rotary drill bit including a bit body having a plurality of cutting elements mounted on the outer surface thereof comprises the steps of forming a hollow mould for moulding at least a portion of the bit body, packing the mould with powdered matrix material, and infiltrating the material with a metal alloy in a furnace to form a matrix. Before packing the mould with powdered matrix material, there are postioned in spaced locations on the interior surface of the mould a plurality of cutting element, each of which is formed of a material, such as a polycrystalline diamond material, which is thermally stable at the temperature necessary to form the matrix. Also positioned in the mould, adjacent the rearward side of each cutting element, is a support material such that, at least after formation of the matrix, the support material has a higher modulus of elasticity than the matrix.

Abstract: A rotary drill bit (10) has a nozzle assembly (24) positioned within a nozzle bore (22). Nozzle assembly (24) has a nozzle member (34) with a port (40) deviated from the longitudinal axis of the nozzle member (34). A retaining nut (54) is threaded within the threaded bore (22) while the nozzle member (34) is held against rotation thereby to maintain the port (40) in a predetermined rotational position upon final installation.

Abstract: A tri-cone drill bit (10, 10A) comprising a plurality of conical roller cutters (16, 16A) having hard metal cutting elements thereon and being so positioned relative to each other that their rotational axes are offset from the rotational axis of the drill bit (10, 10A), and a drilling fluid nozzle system for directing a pressurized fluid stream (76, 76A) across certain of the cutting elements and thereafter against the formation generally at the bottom of the well bore so that when the drill bit (10, 10A) is used in its most advantageous areas, such as the soft, medium-soft and plastic formations, the nozzle system prevents "balling up" of the cutters and greatly increases the drilling efficiency of the bit. In one embodiment (FIGS. 15-20) the drill bit body (12A) has vertically extending recessed portions (21A) formed at the junctures (19A) of the lugs (15A) to provide flow passageways for the upward flow of drilling fluid and entrained cuttings.

Abstract: A drill bit comprising a bit body detachably secured to a drill string having a chamber therein to receive drilling fluid at a first pressure from the drill string, a nozzle for exit of the drilling fluid to the space between the bit body and the well bore at a second pressure lower than the first, and a depending leg; a roller cutter; a bearing assembly for rotatably mounting the roller cutter on the leg; a lubrication system in the bit body comprising a reservoir of lubricant, passaging for flow of lubricant from the reservoir to the bearing assembly, a seal member for blocking flow of lubricant out of the bit, an expansible chamber for pressurizing the lubricant to a third pressure greater than the second but less than the first, and a biased diaphragm for pressure compensation secured in a recess in the bit body in fluid communication at one side thereof with the lubricant and at the other side thereof with the drilling fluid in the space between the bit body and the well bore; and a sensor for sensing a

Abstract: A drag type rotary drill bit (10) having mounted on its lower face (22) a rigid integral holder (30) for a plurality of polycrystalline diamond compact (PDC) cutting elements (42) secured to a planar face (60) of the holder (30). An upper projecting tapered end portion (71) of the holder (30) defines tapered surfaces (72, 73) with the lower tapered surface (72) extending at a relatively large clearance angle (B) to provide a relatively small wear flat surface on the holder (30).

Abstract: A metal matrix (53) of a blade (30) on a drag-type rotary drill bit (10) is formed about a plurality of diamond cutting elements (56) so that the entire surface areas of the cutting faces (62) are exposed and engage the formation to be cut in a drilling operation. The cutting elements (56) are secured by a mechanical interlocking bond or attachment (68, 70) between the cutting elements (56) and matrix (53) without utilizing the cutting faces (62) for securement.

Abstract: A seal assembly (34) for a roller cutter drill bit (10). Seal assembly (34) has an elastomeric resilient O-ring 44 adjacent one sealing surface and a dynamic elastomeric O-ring (46) adjacent another sealing surface. A rigid carrier (52) is mounted between the O-rings (44, 46) which are unsecured to their associated sealing surfaces. A key (54) on carrier (52) limits rotation of the carrier (52) and static O-ring (46) relative to the associated sealing surface (38).

Abstract: A rotary drill bit comprising a bit body having at least one depending leg at its lower end having a generally cylindrical bearing journal, a roller cutter of generally conical shape having a recess therein receiving the journal a bearing system for rotatably mounting the roller cutter on the journal, and a lubrication system for providing lubricant to the bearing system comprising a reservoir of lubricant, passaging in the bit body for fluid communication between the reservoir and the bearing system, and a seal member between the roller cutter and the journal blocking flow of lubricant out of the bit body. The seal member is of annular shape and is held in a seal cavity between the roller cutter or the journal, with an annular engagement face thereof in sealing, sliding frictional engagement with one of the bearing members.

Abstract: A hardened bearing surface (36, 38, 42, 48, 50, 51 and 52) on a component (14, 16) of a rotary cutter drill bit (10) and the method of forming same. A composite mix (60) of alloy material (56) and base material (54) forms the hardened bearing surface (36, 38, 42, 48, 50, 51 and 52) with the alloy material (56) consisting of at least ten (10) percent of the adjacent base material (54) and of an optimum of around fifty (50) percent. The alloy material (56) of predetermined amounts of predetermined elements is positioned on the base material (54) and a precisely controlled high energy density source, such as a laser beam (58), melts the alloy material (56) and adjacent base material (56) to form the composite mix (60) defining the hardened bearing surface.

Abstract: A drill bit comprising a bit body detachably secured to a drill string having a chamber therein to receive drilling fluid at a first pressure from the drill string, a nozzle for exit of the drilling fluid to the space between the bit body and the well bore at a second pressure lower than the first, and a depending leg; a roller cutter; a bearing assembly for rotatably mounting the roller cutter on the leg; a lubrication system in the bit body comprising a reservoir of lubricant, passaging for flow of lubricant from the reservoir to the bearing assembly, a seal member for blocking flow of lubricant out of the bit, an expansible chamber for pressurizing the lubricant to a third pressure greater than the second but less than the first, and a biased diaphragm for pressure compensation secured in a recess in the bit body in fluid communication at one side thereof with the lubricant and at the other side thereof with the drilling fluid in the space between the bit body and the well bore; and a sensor for sensing a

Abstract: A rotary drill bit (10) having a plurality of diamond cutting elements (48) each having a cutting face (60) with a discharge nozzle (64) therein. The discharge nozzle (64) directs the flow of drilling fluid away from the cutting face (60) and is surrounded by the cutting face (60).

Abstract: A method and apparatus for machining on a rotary lathe (L) the bearing journal (14) of an elongate rotary drill bit body section or so-called lug (W). A workpiece holder (H) adapted to be removed from and positioned on the lathe (L) grips the bit body section (W) in a predetermined position. The holder (H) with the drill bit body section (W) is inserted loosely within an inclined pocket (O) on the lathe (L) defined by parallel upper and lower planar surfaces (74, 76). Positioning pins (86) on the lathe (L) engage the lower surface of the holder (H) and move the holder (H) against the upper planar surface (74) of the pocket (O) for the machining operation. After the machining operation on the bearing journal is completed, holder (H) is released by the positioning pins (86) and the holder (h) with the finished bit body section then removed from the lathe (L).