Abstract: A seal assembly (46) for a rotary drill bit (10) having a pressure balanced lubrication system is mounted in a pocket (48) between a journal (16) and a roller cutter (18). The seal assembly (46) has a pair of rigid seal rings (50, 52) in sliding sealing contact with each other and a pair of elastomeric seal rings (54, 56) in side by side relation sealing against the inner peripheral surfaces (62, 64) of the rigid seal rings (50, 52) for continuously urging the sealing faces (58, 60) of the rigid seal rings (50, 52) into sliding sealing contact. The pressure balanced lubrication system has a pressure compensating diaphragm (38) and lubricant passages (40, 42, 44) extending directly from the lubricant reservoir (35) to the lubricant chamber (48A) in the pocket (48) for minimizing fluid pressure differentials between the lubricant chamber (48A) and the drilling fluid chamber (48B).

Abstract: A seal assembly (46) for a rotary drill bit (10) having a pressure balanced lubrication system is mounted in a pocket (48) between a journal (16) and a roller cutter (18). The seal assembly (46) has a pair of rigid seal rings (50,52) in sliding sealing contact with each other and a pair of elastomeric seal rings (54,56) in side by side relation sealing against the inner peripheral surfaces (62,64) of the rigid seal rings (50, 52) for continuously urging the sealing faces (58, 60) of the rigid seal rings (50, 52) into sliding sealing contact. The pressure balanced lubrication system has a pressure compensating diaphragm (38) and lubricant system has a pressure compensating diaphragm (38) and lubricant passages (40, 42, 44) extending directly from the lubricant reservoir (35) to the lubricant chamber (48A) in the pocket (48) for minimizing fluid pressure differentials between the lubricant chamber (48A) and the drilling fluid chamber (48B).

Abstract: A rotary drill bit (10) having a plurality of roller cutters (20) with rows (32A, 32B, 32C, 32D) of cutting inserts (34,36,38,40) mounted within sockets (35,46) on the frusto-conical cutter body (30). The cutting inserts 34,36,38,40) have cutting surfaces formed with a wear-resistant material with certain cutting inserts (36,38) being formed of a wear-resistant material having a hardness higher than the hardness of the wear-resistant material on the remaining inserts (34,40) in each row. The hard cutting inserts (36,38) are positioned in each row in a predetermined pattern intermingled in a generally uniformly spaced pattern with the softer cutting inserts (34,40) and comprising generally between 20% and 50% of the total number of cutting inserts in a particular row.

Abstract: A drag type drill bit (10) having a plurality of solid block-like holders (30, 32, 34) secured to and projecting from the bit body (12), each holder (30) having a plurality of cutting elements (36) thereon defining spaced cutting edges 54. Each cutting element (36) has a planar cutting face (46) and a cutting edge (54) extending along the cutting face (46) with the cutting face (46) extending in a generally radial direction with respect to the axis of rotation of the bit (10). The holders (30, 32, 34) are arranged in a plurality of rows extending outwardly from adjacent the axis of rotation of the drill bit (10) and the holders (30, 32, 34) in each row are staggered rearwardly with respect to the direction of rotation.

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 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: This invention discloses a rolling cone drilling bit having a plurality of cutters which have inserted therein hard metal cutting elements preferably formed of tungsten carbide alloy; and in which bit the rolling cone cutters are located in such a manner that their rotational axes are greatly offset from the rotational axis of the drill bit. In addition, a fluid jetting system is provided in the invention that directs a pressurized fluid spray across the main cutting inserts and against the formation face so that when the drill bit is used in its most advantageous areas, such as the soft, medium-soft and plastic formations, the jetting system prevents "balling up" of the cutters and greatly increases the drilling efficiency of the bit.

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: This invention discloses a rolling cone drilling bit comprising a plurality of conical roller cutters 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, and a drilling fluid nozzle system for directing a pressurized fluid stream 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 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.

Abstract: Methods and apparatus are disclosed for the rapid and efficient drilling of oil well and other types of bore holes through tough abrasive underground formations, which methods and apparatus utilize high drag intermittent contact and cooling techniques to provide good rates of penetration with low wear and heat deterioration on the drilling tools.

Abstract: A rotary drill bit comprising a bit body having at least one depending leg at its lower end and at least one roller cutter rotatably mounted on the leg. The roller cutter comprises a frustoconical roller cutter body and a plurality of cutting elements projecting from the cutter body to tips adapted to bear on the bottom of the well bore, with the tips defining, upon rotation of the bit, a first cutting surface of the bit extending over substantially the entire area of the bottom of the well bore. At least one drag cutter extends down from the bit body and comprises a support and a plurality of drag cutting elements on the support, each having a lower cutting edge.

Abstract: Inserted hard metal cutting elements are disclosed which are advantageous for inserting into the cutters of drilling bits used in drilling underground formations. The inserted cutting elements comprise asymmetrical inserts placed in at least one row of a cutter in alternating alignment circumferentially therearound.

Abstract: A rolling cutter drill bit is disclosed which utilizes a main body having a threaded end for connection in a drill string, and a plurality of rolling cutter assemblies joined to the bottom of the bit body by means such as electron beam welding.

Abstract: A drill bit having a body with a shaft thereon, a roller cutter, an annular thrust bearing, means for connecting said roller cutter to the thrust bearing, means for retaining said thrust bearing on the shaft, and a lubrication system containing the thrust bearing and the retaining means with the lubrication system seal positioned between the outer edge of the roller cutter and the base of the shaft.