Abstract: A flat seal (32) for a roller cone rock bit (10) is provided. Flat seal (32) includes a ring-shaped metallic spring (80). Metallic spring (80) has an inner face (88) with an annular inner edge (92) for contacting a sealing surface (72) of a cone (18) in a roller cone rock bit (10). Metallic spring (80) also has outer face (86) with an annular outer edge (90) for contacting a sealing surface (70) of a spindle (16) in the roller cone rock bit (10). Metallic spring (80) has a relaxed axial pitch greater than a clearance (76) between sealing surfaces (70) and (72) of cone (18) and spindle (16). Flat seal (32) also includes an annular inner elastomer shroud (84) disposed on inner face (88) of metallic spring (80) such that the annular inner edge (92) is exposed. Flat seal (32) further includes an annular outer elastomer shroud (82) disposed on outer face (86) of metallic spring (80) such that the annular outer edge (90) is exposed.

Abstract: An improved O-ring seal for rock bit bearings comprises a body formed from a resilient elastomeric composition and a modified surface comprising a surface enhancing material integral with the body. The surface comprises a layer of surface enhancing material that encapsulates and is molecularly bonded to an underlying surface of an elastomeric seal body. The surface enhancing material selected may include metal disulfides, fluoropolymers, ethylene polymers, silicone polymers, and urethane polymers. The O-ring surface displays enhanced properties of reduced break-off friction, increased lubricity and wettablity, and increased thermal resistance. These enhanced surface properties serve to minimize stick-slip and material loss from the O-ring surface resulting from stick-slip, thereby increasing the service life of the O-ring seal and rock bit.

Abstract: An improved O-ring seal for rock bit bearings is formed from a resilient elastomeric composition comprising a multiplicity of low friction wear resistant particles distributed uniformly throughout the composition. The low friction wear resistant particles can have a rounded or non-rounded configuration. The low friction wear resistant particles located near the surface of the O-ring are exposed through wear of the elastomeric component to form wear pads that contact adjacent rotating rock bit sealing surfaces. The wear pads serve to reduce the break-off friction between the adjacent sealing surfaces and minimize the occurrence of stick-slip, thereby enhancing the service life of the O-ring seal and rock bit.

Abstract: An improved rigid face seal that minimizes pressure fluctuations in the lubricant in the vicinity of the seal assembly. The assembly has a first ring with a radial seal face that opposes and engages an opposed radial seal face of a second rigid ring. A first resilient energizer ring is compressed between opposed, generally conical surfaces, one on the first rigid seal ring and the other in a shaft seal groove. The mid-section of the first energizer ring is positioned relative to the journal bearing surface such that its inner periphery is inside the journal bearing surface and thereby defines an essentially constant, lubricant-filled volume between the seal assembly and the shaft seal groove--even as the cutter and seal assembly move relative to the shaft during drilling. A second energizer ring is provided to maintain sealing engagement between the radial seal faces of the first rigid ring and the second rigid ring.

Abstract: An earth boring bit having a body and a cantilevered bearing shaft extending inwardly and downwardly from the body. A rotatable cutter with an open end is assembled over the shaft, which has a radial bearing surface formed around a longitudinal axis. The cutter has a radial bearing surface sized to permit assembly over the journal surface of the shaft. The shaft and cutter have opposed thrust bearing surfaces, one of which has a gradually tapered outer region and a planar inner region to gradually reduce peak stress from a maximum to a minimum and avoid abrupt changes in stress from a high to a low value.

Abstract: An earth boring bit of the type having at least one rotatable cutter on a bearing shaft, a hydrostatic pressure compensator to balance the pressure of the lubricant with the pressure of the drilling fluid in the borehole, a metal face seal assembly of the type that enables movement of the seal to compensate for dynamic pressure changes in the lubricant as the cone moves on the bearing shaft, and a protuberance extending from a metal ring of the seal assembly into an aperture in the body of the bit adjacent the shaft with both axial and radial clearances sufficient to enable compensating movements of the seal assembly.

Abstract: An earth boring bit having a body, pressure compensating lubricating system and cantilevered bearing shaft with an annular seal surface and a radial seal surface. A cutter is rotatably secured to the bearing shaft, with an annular seal recess having radial and cylindrical seal surfaces to oppose the seal surfaces on the body and bearing shaft to define a seal gland. A resilient and annular packing ring is compressed between the cylindrical seal surfaces, but has a length less than the minimum length of the gland. A shroud extends inwardly near the outer backface a selected distance behind the packing ring to bias it inwardly. The shroud extends inwardly toward the bearing not more than about 30% of the cross-sectional thickness of the O-ring in the relaxed condition. The O-ring is compressed in a range of about 10 to 15 percent.

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: Sealed bearing rotary cone drill bits are subject to seal wear from detritus or debris generated during operation of the drill bit in a borehole. The debris invades the seal gland area resulting in premature cone bearing failure. A shale burn plug secured in the leg back face and positioned between the base of the rotary cone and the leg back face has a shale or detritus diverting ridge formed in the face of the plug. Additionally, the burn plug is energized to urge the ridged face of the burn plug against the base of the rotary cone; the ridge being radially oriented to divert debris away from the seal gland.

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: This invention relates to a rotary drill bit having a body with leg members, where each of the leg members has a projecting conical cutter receiving journal. A conical cutter having an axially extending recess open at one end has friction reducing bearings interior to the conical cutter for rotatably mounting the cutter on the journal. A plurality of lubricant carrying conduits interior to the leg members extending into the bearings provides lubricant for the bearings. This invention provides an improved sealing arrangement for preventing an excessive loss of lubricant from the bearings. The conical cutter is adapted with seal receiving grooves at its open end of the recess to receive two seals, with a circumferential seal gap located between the seals. The outer seal is less rigid than the inner seal and when the circumferential seal gap is supplied with lubricant it bleeds past the outer seal to wash away drilling debris.

Abstract: A rotary rock cutter cone is rotatively supported while being axially located and retained on a cooperating cantilevered journal shaft depending from a rock bit body by plain friction bearing means.A primary stationary thrust face is provided by a radially extending surface of the journal shaft adjacent the distal end of the journal shaft.An annular ring, fitted about the journal shaft, forms a gland for housing a grease seal which impinges upon the journal shaft. A radially extending distal surface of the annular ring runs in cooperation with a radially extending stationary thrust face formed by a secondary thrust member. The secondary thrust member is axially secured to the journal shaft thus axially trapping the annular ring adjacent to the supported end of the journal shaft.A radial bearing bore centrally enters the base of the cone and extends to a radially extending primary thrust bearing surface within the cone.

Abstract: A sealing member for relatively movable, e.g., rotating or reciprocating, members comprises a pair of annular rings each with a radially extending wall and an axially extending wall defining an annular seal gland. An elastic spring member compression-loaded in the seal biases the exterior surfaces against the bearing surfaces. The ring members are preferably of TEFLON, or like polytetrafluoroethylene plastic, RYTON, polyphenylene sulfide, or a soft elastic metal capable of being compressed by the spring member against the walls of the surface being sealed. The spring is a rubber or elastomeric O-ring or the like. Other spring members, such as a Belleville spring assembly or the like, may be used. This seal is characterized by its operation at elevated temperatures, i.e., up, to 1000.degree. F.

Abstract: A roller bit comprises a plurality of legs each of which has a longitudinally extending pin. A cutting cone is rotatably mounted on each of the pins and a prefabricated sealing insert is fixedly connected at a longitudinally inner end of each of the pins. A sealing element is positioned between the cone and a sealing surface of the insert. The insert is formed of a material having a hardness greater than a core hardness of the pin.

Abstract: An earth boring rotary drill bit suitable for use in drilling oil wells and the like includes a rotating cone mounted on a journal that is protected by a primary seal and a secondary seal. The seals provide independent sealing action while coacting to stabilize the rotary motion of the cone. The primary seal defines a moving sealing surface in contact with the journal, and the secondary seal defines a moving sealing surface in contact with the rotating cone. The journal can have a frusto-conical or cylindrical configuration.

Abstract: An improved drill bit seal arrangement, including a seal ring having a boronized outer annular surface which is fabricated separate and apart from the journal bearing structure of the drill bit arm. The seal ring boronized surface is polished to define a smooth non-abrading surface for the elastomeric seal. The seal arrangement enhances the wear resistance of the seal between the drill bit arm and the cutting cone, thereby increasing the life span of the drill bit.

Abstract: An earth boring bit having an improved two piece bearing and seal assembly containing a cantilevered bearing lug that is threaded to receive a mating bearing sleeve, the lug having a transverse shoulder intersected by a mouth on the sleeve to define a bearing shaft upon which is supported a rotatable cutter. A lubrication system includes a hydrostatic pressure compensator and seal means, the transverse shoulder being positioned inwardly of the seal means toward an inner end region of the lug to avoid exposure of the transverse shoulder of the lug and the mouth of the bearing sleeve to ambient drilling fluid. The seal means is a rigid face seal assembly which includes a rigid, sealing ring and a resilient energizer ring.

Abstract: A rotatable seal cage assembly for positioning between relatively movable members including a ring with inner and outer circumferential edges, which edges are joined by two flat side surfaces extending therebetween. An annular projecting surface extends from one of the ring side surfaces. A projection extends from the other side surface of the ring to be engaged by rotatable bearings to rotate the ring when relative rotation of the members occurs. Radially spaced seals are provided on each side of the annular projecting surface to seal between the rotatable seal cage assembly and each of the relatively movable members and inhibit damage to the radially spaced seals between the relatively movable members.

Abstract: A sealing relationship between a rotatable and stationary member is formed by a seal arrangement between the rotatable and stationary member wherein a first member engages the seals forming the sealing relationship and a second member is rotatable by the rotatable member to rotate the first member about the stationary member at a substantially reduced rotational speed relative to the rotational speed of the rotatable member to inhibit damage to the sealing relationship.

Abstract: An underreamer including a body having a bore therethrough, an arm mounted at its upper end to the body, a conical cutter mounted for rotation on the lower end of each arm, a cup-shaped thrust bearing between the cutter and the arm, means extending through the arm to secure the cutter on the arm including pin elements that extend into a groove in the cutter to prevent rotation movement between the arm and the thrust bearing to lock the thrust bearing to the arm. The arms are pivotally mounted in slots in the body and means are provided for moving the arms to their cutting position with their lower ends positioned radially outward from the body.

Abstract: An earth boring bit having a lubrication system that includes a pressure compensator and seals to confine lubricant within the bearings between rotatable cutters and shafts, the seals being of the asymmetrical shear/compression type, each half of which having a load deflection curve resulting from components satisfying the following criteria:D.sub.H >A.sub.p SandD.sub.C >A.sub.p S[(S-1)/S].sup.1/2Where:D.sub.H =Assembly deflection of shaft seal ring with bearing thrust faces in contact (in.);D.sub.C =Assembly deflection of cutter seal ring with bearing thrust faces in contact (in.);A.sub.p =Axial cutter play (in.);S=Ratio seal to cutter movement.Also preferably, D.sub.C .perspectiveto.D.sub.H [(S-1)/S].sup.1/2.

Abstract: An earth boring bit having a cantilevered bearing shaft and a compensator system to equalize the pressure of the lubricant with the hydrostatic pressure of the drilling fluid surrounding the bit. A rigid face seal assembly, positioned between the cutter and bearing shaft of the bit, moves axially in response to, and to compensate for, dynamic pressure changes in the lubricant adjacent the seal. The positioning of the seal groove and seal assembly in relation to the bearing surface is such that rigid face seal movement is decreased relative to axial cutter movement during drilling to enhance seal life. Preferably the ratio of rigid ring movement to axial cutter movement is substantially one half to one.

Abstract: A sealed bearing rock bit for drilling oil wells and the like that includes a spring bearing member rotatably supporting the cutters on the pins of the bit. The resiliency of the spring bearing member on each pin is utilized to bias an annular seal member in a direction to maintain a face-type seal in fluid-tight, sealing engagement preventing loss of lubricant from the bit and preventing the ingress of deleterious material into 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: 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: An earth boring bit with sealed and lubricated bearings and rotatable cutters, the seals being isolated from detritus in the borehole by a seal protector ring and groove. The ring, generally L shaped in cross-section, has radial and axial clearances from the registering groove to maintain a labyrinth path with selected values, irrespective of cone movement during drilling.

Abstract: A hyrodynamic lubricant sealing element for devices such as rotary cone rock bits, shaft seals and the like which is maintained under sufficient mechanical compression to effect a seal between relatively movable structures. The sealing element defines a sealing surface establishing a seal interface with a relatively movable circular sealing surface and forms a lubricant interface and a contaminant interface at opposite sides thereof. The lubricant interface is of such configuration as to induce a hydrodynamic lubricant wedging activity causing migration of lubricant film in the seal interface from the lubricant interface to the contaminant interface for flushing away any contaminant and for lubrication between the sealing element and sealing surface.

Abstract: A seal assembly particularly adapted for sealing rock bit bearings is disclosed. The seal comprises an O-ring made of a resilient material which swells substantially when effectively exposed to a lubricant used for lubricating the bearing. The O-ring seal is mounted into the rock bit in a relatively low state of compression or squeeze between the surfaces to be sealed. During operation of the bit, the O-ring seal swells due to exposure to the lubricant, and consequently compression or squeeze of the seal increases substantially. The novel seal assembly compensates for undesirable compression set and wear of the O-ring.

Abstract: An earth boring drill bit having roller cutters which are rotatably supported on journals by bushings. At least one of the bushings is formed by a plurality of bushing segments which are positioned about a circular bearing surface having thrust shoulders at each end thereof. The roller cutter elements are assembled about the bushing segments in heated condition, by press-fitting to establish a firmly seated relationship between the cutter and bushing segments upon cooling of the cutter. The rotary cutter is then secured to the bushing segments by means of a locking element to prevent inadvertent disassembly during drilling operations. End portions of the bushing segments engage hardened bearing inserts of cutter support legs to minimize wear during drilling operations. A circular sealing element positioned about the bushing segments establishes sealing engagement with the cutter support legs to prevent ingress of contaminants and egress of lubricant during drilling activity.

Abstract: A sealed rotary drill bit comprising at least one rotatably carried roller cutter (13) and provided with a seal between the cutter and a mounting head (22) for preventing lubricating medium from being discharged from the bearing (14, 15, 16, 17, 18) and impurities from entering the bearing. For purposes of decreasing the friction the seal (22) is provided with a low friction material on a portion of the seal which engages the head to promote rotation between the seal and the head. The portion of the seal which engages the roller cutter has a material of higher frictional coefficient to resist relative rotation between the seal and the roller cutter (25).

Abstract: A rotary drill bit comprising a head and a roller cutter rotatably carried thereon, wherein an annular sealing means is arranged in an annular chamber adjacent to a gap between the roller cutter and the head. At least one of the sealing surfaces of the chamber is generally seen V-shaped. According to the invention larger sealing pressure is obtained at two circumferentially spaced portions of the V-shaped sealing surface than at an intermediate portion thereof while simultaneously maintaining sealing pressure along the entire circumferential extent of the sealing means between said spaced portions.

Abstract: An improved seal for a rotary drill bit includes a pair of ring seals comprised of dissimilar materials disposed axially, adjacently to one another intermediate a stationary journal and a rotating cutter to present multiple sealing interfaces so that one or more of the ring seals may rotate with respect to another or the journal or rotating cutter. One of the ring seals may preferrably be fabricated of material exhibiting elastomeric characteristics.

Abstract: An earth boring bit having a pressure compensating seal assembly which includes a resilient packing ring, a rigid backup ring and a wave spring to permit axial displacement of the resilient ring in an elongated seal groove while resisting destructive distortions of the resilient ring. The lubrication system has a lubricant volume correlated with the volume of the passages and spaces and the maximum seal displacement. A measured amount of lubricant is withdrawn from the system during assembly for subsequent compression as the bit is lowered into a liquid-filled bore hole to position the seal assembly intermediate the end walls of the seal groove.

Abstract: An improved seal for utilization with earth boring drill bits which employ rolling cutters mounted on shafts extending from face surfaces on the drill bit body. The improved seal includes a generally cylindrical elastomeric seal which is disposed around each shaft with one end of the generally cylindrical elastomeric seal in sealing and sliding engagement with the face surface surrounding that shaft. The second end of the generally cylindrical elastomeric seal is engaged in sealing and sliding engagement with a surface on the rolling cutter. A rigid generally cylindrical ring is disposed within each generally cylindrical elastomeric seal preferably near the outer surface thereof and serves to minimize radial distortion of the generally cylindrical elastomeric seal in response to axial compression.

Abstract: An earth boring bit having a cantilevered bearing shaft and a compensator system to equalize the pressure of the lubricant with the hydrostatic pressure of the drilling fluid surrounding the bit. A rigid face seal assembly, positioned between the cutter and bearing shaft of the bit, moves axially in response to, and to compensate for, dynamic pressure changes in the lubricant adjacent the seal. This is accomplished by the positioning and sizing of resilient energizer rings in relationship to the geometries of the mating grooves between the cutter and shaft and the rigid sealing rings of the face seal assembly.

Abstract: The present invention relates to an improved rotary drill bit having a bit body with at least one bearing pin attached thereto for rotatably carrying a roller cutter over a bearing system. The bearing system includes at least a forward bearing and a rear bearing with at least one inflow passage provided in the bit body for supplying fluid through the passage to the rear bearing during operation of the bit for flushing and for cooling of the rear bearing. The passage terminates in the bearing system ahead of a forward end of the rear bearing between an intermediate sealing arrangement and an annular outlet gap provided between the bit body and the roller cutter. The bearing pin includes a flange for axially fixing a forward end of the rear roller bearings with the inflow passage preferably terminating on the periphery of the flange. The sealing arrangement preferably engages a forward radial surface of the flange on the bearing pin.

Abstract: A compressible pressure compensating member is disposed within a sealed lubricant volume enclosing a bearing and seal system of an earth boring apparatus. Lubricant is maintained within the volume by metal face seals so that both the bearing and the seal structure are lubricated thereby. As the lubricant expands, due to thermal expansion under use, the increased pressure is accommodated by compression of the compressible member so that no lubricant is expelled through the seals. When the lubricant cools and contracts, the compensator expands to maintain the lubricant volume at the initially filled level.

Abstract: A seal assembly for a rotary drill bit of the type comprising a bearing journal constituting a first bearing member, and roller cutter having a blind end bore therein, constituting a second bearing member, receiving the journal and an annular recess at the open end of the bore, the annular recess and journal defining an annular cavity in the bit. The seal assembly is positioned in the cavity for holding lubricant in the bit and comprises a ring of relatively rigid material movable with respect to the journal and the roller cutter in the longitudinal axial direction thereof and having a sealing face. An elastomeric seal member sealingly engages the movable ring and one of the bearing members and biases the ring to a position in which the sealing face of the ring is in sealing engagement.

Abstract: A sealed, internally lubricated rotary roller drill bit for drilling hard earth formations in which internally disposed axially, thrust and ball anti-friction bearings are used in combination and in which a first seal means is provided for preventing the introduction of drilling debris and a second seal means is provided to prevent the introduction of such debris and to maintain the lubricant inside of the bit under pressure. A pressure relief means is provided to allow excess lubricant to flow around one of the seals. A stream of air is directed through the bit, first in a direction to "clean" the bore hole and in further directions to allow ready access to a lubricant fitting and to effect a seal at the interface between rotating portions of the bit.

Abstract: The present invention relates to a drill bit (10) incorporating one or more rotary cutters (14). The rotary cutters (14) are supported for rotation by a bearing assembly including ball bearings (28) running in races (24, 26) in the rotary cutter and drill bit body (20). The bearing assembly further includes an annular bushing (34). A sealing assembly (36) including an O-ring seal (38) is provided to seal lubricant within the bearing assembly and prevent external contaminants from entering the bearing assembly. Corrosion has been found to destroy the seal surfaces (42, 44) against which the O-ring seal acts (38). It has been found that plating the sealing surfaces with a material passive to the electrochemical system or higher in the electromotive series than the material forming the sealing surfaces reduces corrosion. Alternatively, a sacrificial anode (68) is provided about the sealing surfaces to render the surfaces cathodic and resist corrosion.

Abstract: A resilient O-ring shaft seal for use in a rotary rock bit is described wherein the degree of squeeze imposed upon the O-ring seal is increased in one or more discrete steps, occurring as drilling conditions or bearing deterioration cause rising temperatures to be imposed on the seal. The squeeze is increased in discrete steps through a thermally related shape change in one or more nitinol, or the like, back up rings positioned adjacent to the packing ring seal housed within a seal gland. The seal gland is formed between a rock bit journal and a rock cutter cone rotatably mounted to the journal.

Abstract: An earth boring bit has a bearing seal that floats to accommodate angular and axial movement of the cutter with respect to the shaft. The seal is located in an annular groove formed in the shaft. A supporting ring is located in the groove. The supporting ring has an inner diameter larger than the inner diameter of the groove to provide a clearance for allowing the supporting ring to float. An elastomeric ring is located on the outer circumference of the supporting ring. The supporting ring presses the elastomeric ring into sealing contact with the cutter. The elastomeric ring is also pressed on its sides to provide sealing.

Abstract: A rotary drill bit comprising a roller cutter (12) which is rotatably carried over a bearing system. The bearing system comprises at least one roller bearing (16). Fluid is supplied to the bearing system for flushing and lubricating and when needed cooling thereof. For purposes of ensuring suitable fluid flow through the roller bearing (16) and thus ensuring satisfactory lubrication thereof the rollers in the roller bearing (16) are provided with an axial bore (25).

Abstract: A two-stage vent cap type pressure relief valve for a rock bit is disclosed that relieves low pressure gases in a first stage and higher pressure gases in a second stage.

Abstract: An earth boring bit has features particularly for use in drilling holes in which compressed air is used as a drilling fluid. The bit has three rotatable cutters, each having a cavity for mounting on a depending bearing pin. The cutter and the bearing pin have a thrust bearing in the lower portion of the cavity and a roller bearing in the upper portion of the cavity. The bit has air passages for discharging through the roller bearing gaseous fluid pumped from the surface. A seal seals the nose area from the roller bearing area. Liquid lubricant is located in the nose area for lubricating the bearing surfaces in this portion of the bit. A lubricant chamber is in communication with the nose area. The lubricant chamber cavity has a sliding piston for applying pressure to the lubricant. The sliding piston is driven by the compressed air in the air passages.

Abstract: An earth boring bit has a friction or journal bearing with features that allow cooling fluid to be circulated near the bearing. The bit is of the type having rotatable cutters carried by depending bearing pins. A bushing is stationarily mounted on the bearing pin, with the bushing's inner surface in contact with the outer surface of the bearing pin. One of the surfaces has a plurality of grooves that extend at least partially around the bearing pin. Passages are formed in the bearing pin and bit for circulating cooling fluid through the grooves. The cutter is mounted on the bushing in rotating and sliding contact to form a journal bearing.

Abstract: An O-ring shaft seal is disclosed to isolate a lubricated bearing from an external environment as utilized in a typical sealed bearing rotary rock bit. The O-ring is confined within a pair of symmetrical and complementry V-shaped surfaces, each surface having a rounded vertex. A first V-shaped surface is formed on a bearing journal which is integral with a body of the rock bit, a second V-shaped surface being formed in a cutter cone mounted on the journal. A pressure differential across the O-ring in either direction will force the O-ring into porportionately tighter contact with the converging sides of both V-shaped surfaces.