Abstract: A rotary cone rock bit, comprises a bit body including a plurality of legs extending therefrom, each of the legs having an outer surface that includes a leading surface and a trailing surface, a roller cone rotatably supported on each of the legs, a bearing system between each cone and the leg on which it is supported, and a lubricant reservoir in fluid communication with the bearing system. The reservoir can be provided with a wear resistant plug, if desired. In the present bit, the reservoir has at least one opening positioned in either the leg's leading surface, trailing surface, center surface, shoulder surface or some combination of these. Alternatively, the reservoir can be formed inside the bit body, preferably by means of a canister, which can be provided with venting means as desired.

Abstract: A pressure compensating assembly for use in roller cone drilling bits of the sealed bearing type. The compensating assembly includes a hollow body arranged to fit into a cavity in the bit connected with the lubrication system of the bit and the hollow body includes a normally open lubricant passageway extending therethrough. A seal encircles the body on one side of the lubricant passageway and is arranged to sealingly engage the bit and an elastomeric, cup-shaped diaphragm is located on the body and has a lip arranged to sealingly engage the bit on the other side of the lubricant passageway. The diaphragm having a protuberance on the side of the diaphragm facing the passageway and sized to enter and close the passageway. The body, seal, and diaphragm being assembled into a unitary cartridge for introduction into the bit as a unit.

Abstract: A drill bit for use in drilling operations in a wellbore, the drill bit having a bit body including a plurality of bit legs, each supporting a rolling cone cutter; a coupling member formed at an upper portion of said bit body; at least one temperature sensor for monitoring at least one temperature condition of said improved drill bit during drilling operations; and at least one temperature sensor cavity formed in said bit body and adapted for receiving, carrying, and locating said at least one temperature sensor in a particular position relative to said bit body which is empirically determined to optimize temperature sensor discrimination.

Abstract: A pressure compensating assembly for use in roller cone drilling bits of the sealed bearing type. The compensating assembly includes a hollow body arranged to fit into a cavity in the bit connected with the lubrication system of the bit and the hollow body includes a normally open lubricant passageway extending therethrough. A seal encircles the body on one side of the lubricant passageway and is arranged to sealingly engage the bit and an elastomeric, cup-shaped diaphragm is located on the body and has a lip arranged to sealingly engage the bit on the other side of the lubricant passageway. The diaphragm having a protuberance on the side of the diaphragm facing the passageway and sized to enter and close the passageway. The body, seal, and diaphragm being assembled into a unitary cartridge for introduction into the bit as a unit.

Abstract: A fitting for reducing friction between a drilling string and the wall of a well. In a first aspect the fitting has recesses (6) provided along the bore of the fitting to lubricate the interface between the fitting and the drill string to minimise friction. In a second aspect a fitting is provided on a drill string having rotatable roller means (21) which can rotate about a point of rotation (23) so as to minimise both axial and rotational friction. According to a third aspect the fitting comprises an inner section (30) secured to a drill pipe (35) or other fitting and an outer section (31) rotatable about the inner section (30). Preferably a sealed bearing (36, 42-47, 37, 38) is provided between the inner section (30) and outer section (31).

Abstract: A rotary cone rock bit, comprises a bit body including a plurality of legs extending therefrom, each of the legs having an outer surface that includes a leading surface and a trailing surface, a roller cone rotatably supported on each of the legs, a bearing system between each cone and the leg on which it is supported, and a lubricant reservoir in fluid communication with the bearing system. The reservoir can be provided with a wear resistant plug, if desired. In the present bit, the reservoir can be pressured-balanced with fluid in the bit plenum or the borehole annulus, or maintained at some desired differential with respect to either of these. Alternatively, the reservoir can be formed inside the bit body, preferably by means of a canister, which can be provided with venting means as desired.

Abstract: In a drill bit which has a reservoir for storing a supply of lubricant, generally grease, a lubricant passage is formed for flow of lubricant from the reservoir to the bearing. A relief port is formed in the drill bit body to connect at least one of the reservoir and the lubricant passage with an outside surface of the drill bit body. A normally-closed relief valve is mounted in the relief port to selectively permit fluid flow through the relief port and protect the lubrication system against changes in pressure, especially increases in pressure on the grease side, such as might be caused by thermal expansion of the grease or the production of off-gases by the grease. The valve is provided in the form of a small screw-in unit capable of separate manufacture and testing and comprises a valve body carrying a flexible diaphragm element. Venting is provided via a puncture in the diaphragm element.

Abstract: A method and apparatus for loading lubricant into a bit chamber of an earth boring bit measures and controls the pressure of pressurized lubricant at the bit chamber while the lubricant is being loaded into the bit.

Abstract: The present invention is a low differential pressure relief valve made up of a valve body and an elastic membrane for downhole tools, especially rolling cutter drill bits. An aperture is formed in the membrane and a valve body with protruding end stops is mounted in the aperture. The thickness and shape of the valve body are such that the aperture is stretched when assembled. The amount the membrane is stretched and the geometry of the protruding end stop, control the differential relief pressure. The valve body and each end stop can be designed so that the pressure relief setting will be different, depending upon which side of the membrane has the higher pressure. The relief device may be adapted to be integral with existing elastic membrane type lubricant pressure compensation devices for downhole tools.

Abstract: A drill bit for boring a bore hole in an earthen formation comprises: a bit body having a pin end, a cutting end and a longitudinal bit axis and including at least two legs extending from the cutting end, each of the legs including a bearing that rotatably supports a cutter cone. The bit body further includes a fluid flow system, including a flowway in said pin end that is in fluid communication with at least one exit port in the cutting end, the exit port being defined by a nozzle boss and disposed adjacent one of the legs. Each of the legs includes a leading side surface, a trailing side surface, and a center panel, and at least one of said legs is asymmetric such that its trailing side surface is larger than its leading side surface. The present bit can also include a lubricant system that has its opening in the trailing side of the leg, and can further include various wear resistant coatings and inserts on its surface.

Abstract: A relief valve for use in roller cone drilling bits of the sealed bearing type and other types of sealed fluid systems. The relief valve includes a valve body arranged to fit into the lubricating system of the bit and an elastomeric valve member having a flow port therein that is normally closed. The valve member includes a flexible lip defining the port that is arranged to permit flow in one direction through the port to relieve pressure above a predetermined value while preventing flow therethrough in the opposite direction.

Abstract: A heavy-duty lubricating grease is shown which includes a synthetic fluid base and a thickener system. The heavy-duty grease can be used in both rolling element and journal type rock bit bearings to drill in heavy-duty, high temperature applications, such as in the bearing structures of rock bits used to drill hot subterranean formations.

Abstract: The present invention relates to a cutter for a raise boring head. The cutter is rotatable about a center axis and mounted, via a shaft of the cutter, in a saddle secured to the raise boring head. The shaft has ends that are secured to the saddle by a fastening mechanism. Bearings are provided between the shaft and a hub of the cutter in order to make it possible for the hub to rotate relative to the shaft. Seals are provided between the shaft and the hub, and the bore which is provided for introducing lubrication into the interior of the cutter. An expansion plug is mounted in the bore. The expansion plug is designed to accommodate the lubrication that enters into the bore from the bearings. A stopper is provided in the bore. The stopper encases a part of the fastening mechanism and is arranged to prevent mud from entering the orifice of the bore.

Abstract: A lubricating sub-assembly for a rock drill, comprising a housing coupled into a drill string carrying a drill bit at its front end, a cavity disposed within the housing for holding a predetermined amount of a bearing lubricant, passages for communicating the interior of the cavity with one or more air circulation passages provided in the bit leading to bearings within the drill bit, and a valve mechanism for dispensing a preset amount of lubricant from the cavity to the communicating means passages.

Abstract: An improved disc type rolling rock cutter, and novel cutterheads employing such cutters. A rock cutter with an improved, simplified structure, with compact bearing, and smooth, rounded blade shape is disclosed. The design incorporates a cutter ring, bearing assembly, and seal assembly. The cutter may be assembled and disassembled for rework by a single worker with simple hand tools. Replacement of worn out cutter rings is done quickly and easily by removing the old ring assembly and then sliding a new ring, bearing, and seal assembly on to the cutter shaft. This simplified assembly is achieved by using a comparatively large shaft which is normally in the range of 30-50% of the ring diameter. The shaft design is sufficiently robust to permit a cantilever mount of the cutter. The unique configuration allows 30,000 lbs. or more thrust to be applied to a 5 inch diameter miniature disc. This capacity permits single disc cutter technology to be applied to smaller bits or cutterheads than previously possible.

Abstract: A rotary cutter includes a shaft adapted to be mounted on a support and defining a longitudinal axis. The shaft includes a bore extending inwardly into the shaft, and a channel extending into the shaft and intersecting the bore. A roller body, having cutting elements, is mounted on the shaft for rotation relative thereto about the axis. Bearings are disposed between the roller body and the shaft, the bearings communicating with the bore. The cutter is lubricated by inserting a filling plug into the bore and forcing lubricant therethrough and into the bearings. The filling plug is then removed from the bore, leaving the bore generally free of lubricant. A hollow cylindrical member and a flexible diaphragm are inserted into the bore, and a nozzle is inserted through the channel for introducing lubricant into the bore. The nozzle is then removed from the channel, and the channel is plugged. The diaphragm flexes inwardly and outwardly in response to variations in external and internal pressures.

Abstract: A rock bit for drilling subterranean formations is lubricated with a grease composition made from a high-viscosity synthetic lubricant basestock and a combination of lubricant additives. The grease composition preferably has in the range of from 1 to 20 percent by weight polyisobutylene, in the range of from 50 to 90 percent by weight ethylene-alphaolefin, up to approximately 40 percent by weight polyalphaolefin, and in the range of from 4 to 45 percent by weight lubricant additives. The rock bit grease composition has a viscosity index in the range of from about 250 to 325, and has an absolute viscosity of greater than about 100,000 centipoise at a temperature of approximately 70.degree. F. and at a shear rate of less than about 40 seconds.sup.-1, without the use of solid metal-containing extreme pressure agents or thickening agents.

Abstract: A rock bit grease composition is prepared by combining synthetic polymer lubricant basestocks comprising a first ethylene-alphaolefin polymer having an average molecular weight in the range of from 3,500 to 4,000, and a polyisobutylene polymer to form a first master. A metal complex soap base thickener is prepared by combining a synthetic polymer lubricant basestocks comprising a second ethylene-alphaolefin having an average molecular weight in the range of from 400 to 800, with an alkali-metal or alkaline-earth metal hydroxide, and at least one fatty acid. A preferred fatty acid is a blend of a first fatty acid having in the range of from 15 to 20 carbon atoms, and a second fatty acid having in the range of from 5 to 12 carbon atoms. The first master and metal complex soap base thickener are mixed together in desired proportions.

Abstract: A roller cutter assembly for use in hard rock tunneling machines comprises a rectangular saddle having a rectangular recess with V-shaped mounting surfaces. Support plates are secured against these mounting surfaces, and the support plates have a shaft extending between them with a non-rotatable head in one plate, and the circular nut in the other plate. The shaft mounts a pair of inner races for tapered roller bearings which run directly on the roller cutter inner surface which forms the outer race for the bearing assembly. Rotation of the circular nut in the recess and on the shaft sets the preload for these bearings. Between the nut and its recess on the adjacent support plate is an annular groove formed in both the support plate and the nut, and an elastomeric diaphragm fits across this groove.

Abstract: A well drilling bit comprises a bit body with a centralized portion and a plurality of radially and circumferentially spaced legs depending longitudinally therefrom. A respective cutter body is rotatably mounted on the free end of each leg with bearing means. The bit body has a respective lubricant passage communicating with each bearing and a respective upwardly opening lubricant reservoir recess, the recess also communicating with a respective vent port opening downwardly through the bit body. A respective lubricating mechanism is disclosed in each lubricant reservoir recess, and each such mechanism comprises an elastomeric pressure compensating diaphragm extending across the recess and sealed with respect thereto, dividing the recess into a lower portion communicating with the vent port and an upper portion communicating with the lubricant passage.

Abstract: An improved pressure compensator of the top-vented type for a roller cone drill bit comprises an elastomeric compensator diaphragm having an annular, peripheral, radially outwardly extending flange. An annular, axially acting compression spring is at least partially imbedded in the flange, elastomeric material of the flange at least partially underlying and overlying the spring for sealing engagement, respectively, with an axially facing shoulder in a recess in the bit body and a cap forming part of the assembly. The cap is disposed above the flange in the bit recess, and has a lower end surface for sealing abutment with the flange. The cap also has a vent communicating a zone above the diaphragm, in the recess, with the exterior of the bit. A retainer is positioned to hold the cap in the recess, thereby also retaining the diaphragm in the recess, and compressing the spring sufficiently to cause sealing engagement on both sides of the flange, but not beyond the elastic limit of the spring.

Abstract: A rock bit for drilling subterranean formations has an improved dynamic O-ring seal for retaining lubricant around the rock bit bearings during operation of the rock bit. Such a bit has a plurality of journal pins, each having a bearing surface, and a cutter cone mounted on each journal pin and including a bearing surface. A grease reservoir is in communication with such bearing surfaces for maintaining grease adjacent to the bearing surfaces. The grease is sealed in with dynamic O-ring seals rotating against a sealing surface with a Vickers hardness of at least 1000 and vibratory burnished to have a surface finish in the range of from 5 to 32 microinches AA. Preferably, the sealing surface is formed on a seal ring interposed between the cone and journal. Preferably the sealing surface comprises a tungsten carbide composite sprayed onto the outside surface of a steel ring which is then welded to a journal.

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: A roller cone rock bit (10) is provided that has a sealing system with double elastomer seals. A first elastomer seal (30) is disposed between a cone (18) having a cavity (24) and a spindle (16). A second elastomer seal (32) is disposed between cone (18) and spindle (16) forming a seal-gap (33). A main lubricant reservoir (49) has a diaphragm (56) disposed between an inner chamber (53) and an outer chamber (60). Inner chamber (53) is in fluid communication with cavity (24), and outer chamber (60) is in fluid communication with external fluids. Cavity (24) and inner chamber (50) are substantially filled with a first lubricant forming a first volume of lubricant. Diaphragm (56) is operable to transmit a pressure of the external fluids to the first volume of lubricant. A seal-gap lubricant reservoir (70) has a diaphragm (78) disposed between an inner chamber (75) and an outer chamber (82).

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: A sealed bearing assembly used in earth drilling is described having a first tubular member and a second tubular member telescopically received in the first tubular member. The second tubular member has an interior passage through which drilling fluids pass under pressure from surface pumps. A clearance space is provided between the first tubular member and the second tubular member defining a lubricant filled sealed chamber. The sealed chamber has a bit end sealed by a bit end seal which faces a drill bit and a pump end sealed by a pump end seal which faces surface pumps. A fixed mechanical seal is disposed in the sealed chamber intermediate the pump end seal and the drill bit end seal. The mechanical seal divides the sealed chamber into a pump end portion and a drill bit end portion. The pump end seal is responsive to pressure exerted by drilling fluids pumped along the interior passage by surface pumps.

Abstract: An earth-boring bit has a bit body and at least one saddle member secured to the bit body to receive and support each of a pair of ends of a journal member. A cutter is mounted for rotation on the journal member and a bearing is defined between the cutter and journal member. A lubricant reservoir is formed in the journal member to receive a quantity of lubricant and is in fluid communication with the bearing. A seal means is provided between the cutter and journal member to retain lubricant in the bearing. A hydrostatic-pressure compensator is disposed in the lubricant reservoir in communication with hydrostatic-pressure in the borehole in which the bit operates. The hydrostatic-pressure compensator responses to hydrostatic-pressure to equalize a pressure differential across the seal means. An internal-pressure compensator is disposed in the lubricant reservoir and is responsive to the internal pressure of the lubricant to prevent the lubricant from being extruded past the seal means.

Abstract: In order to detect when a lubricant is nearly depleted in a lubricant reservoir provided in a sealed rotary cutter rock drill bit, compressed air used for removal of cuttings is passed through a valve in the reservoir. As the lubricant is used up a compressed spring gradually extends. In one embodiment, eventually a vent hole in the valve is opened causing a large pressure drop signifying an empty condition of the reservoir. In another embodiment, the valve is closed when the lubricant is depleted, giving rise to a sudden rise in pressure also signifying an empty condition.

Abstract: A rock bit for drilling subterranean formations has improved dynamic O-ring seals for retaining lubricant around the rock bit bearings during operation at more than 50 meters per minute surface speed on the O-rings. Such a bit has a plurality of journal pins, each having a bearing surface, and a cutter cone mounted on each journal pin and including a bearing surface. A pressure-compensated grease reservoir is in communication with such bearing surfaces for maintaining a grease adjacent to the bearing surfaces. The grease is sealed in with dynamic O-ring seals comprising a perfluorinated terpolymer of tetrafluoroethylene, perfluoro(methyl vinyl ether) and a cure site monomer for introducing crosslinking sites. Preferably the cure site monomer is selected from the group consisting of trifluoroethylene, vinyl perfluoroalkyls and monomers including a perfluoroalkyl ether group.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held in the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

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: A fluid pressure compensator for a lubrication system in a rotary drill bit includes a diaphragm (44) with an enlarged thickness central portion (62) having a generally hemispherically shaped deformation (72) at its center to form a minimal thickness thereat progressively increasing to the enlarged thickness. A self sealing puncture (74) is provided at the center of the diaphragm (44) to relieve excess pressure differentials in the lubrication system internally of the drill bit and excess pressure differentials in the drilling fluid externally of the drill bit. The diaphragm (44) has an enlarged protuberance (64) about its outer periphery which is secured in sealing relation within a groove formed by sealing surfaces (66, 68, 70) on a leg (10) of the rotary bit and associated securing cap (46). A protective cup (42) supports the diaphragm (44) in an extended position and has dimples (58) for supporting the diaphragm (46) on the bottom (40) of the lubricant reservoir (49).

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 lubrication system for an earth boring drill bit having a pressure compensator for minimizing the pressure differential between the drill bit lubricant and the well bore fluid is improved in a manner to prevent sharp edges in the lubricant reservoir wall from damaging the flexible diaphragm and for enabling the lubricant space available in the lubricant reservoir to be maximized. In accordance with a preferred embodiment, the pressure compensator is positioned on a shoulder ring in the lubricant reservoir and the shoulder ring retains the open end of a pressure diaphragm within an interior recess of a compensator cap, the diaphragm sealing against a perimetric wall of the recess. Methods of filling the lubrication system with the pressure compensator installed or removed are provided which avoid stretching or damage to the diaphragm while still maximally filling of the lubrication system with lubricant.

Abstract: An earth boring (rock) bit having a flexible diaphragm located inside the bearing shaft in a cavity between a threaded lug and a mating bearing sleeve. The diaphragm has an enlarged periphery, shaped somewhat like an o-ring, that is confined and sealed between opposed annular surfaces on the lug and the sleeve. The circular periphery of the diaphragm and cavity provide good compensation volume, from which excessive lubricant pressure is relieved by an enlarged portion which is punctured and contoured to discharge lubricant under excessive pressure while excluding drilling fluid. Simplicity and reliability are achieved by the elimination of multiple and complex manufacture and assembly operations.

Abstract: A one-way pressure relief valve assembly is provided for venting the lubricant reservoir of a roller-type well drilling bit. The valve assembly is mounted in the cap of the lubricant reservoir, to open outwardly, and is adapted to provide hydrostatic loading of the valve element to its closed position.

Abstract: An underreamer including a body having a bore therethrough, an arm mounted at its upper end to the body, a sleeve member detachably secured to the lower end of each arm and adapted to receive the frictional wear caused by the rotation of the conical cutter mounted thereto. Bearings and seals disposed between the cutter and the sleeve member provide smooth rotation of the cutter. In addition, locking pins and bearings extending between the arm and the sleeve member secure the sleeve on the arm. The arms are pivotally mounted in slots in the body and mechanical structure is provided for moving the arms to their cutting position with their lower ends positioned radially outward from the body.

Abstract: A drill bit for drilling into underground formations is disclosed, the drill bit having conduits for providing either lubricant or gaseous drilling fluid to the cutting cone bearings. In an alternate mode of operation, a mixture of lubricant and gaseous fluid is supplied to the bearings.

Abstract: A seal element for oil well tools, such as drilling cutters and roller reamers, which allows the drilling media to permeate into the bearing system of the cutter to cool and lubricate the internal mechanism. The seal element is adapted to control the particle size of contaminants flowing into the bearing system by filtering the drilling media. The bearings act as agitators during operation of the cutter to promote fluid motion through the bearing system. The seal and lubrication system may be utilized as a back-up to the conventional lubrication supply or as supplemental lubrication.

Abstract: A drilling tool for use in drilling operations for providing shock absorption capability and lateral support to the rotary drill string. The telescoping axial load shock absorber is positioned immediately adjacent at least one lateral support provided by a reamer or stabilizer. The stabilizer preferably employs a removable fixed blade secured to the tool by an undercut groove. The roller cutter for a reamer is also mounted in a preferred unique manner with the mounting blocks secured in a recess having an undercut retainer portion in the event of bolting failure. The mounting's brackets may be formed integral of the tool body or attached by welding or the like. A preferred form of mounting a blade on a stabilizer tool is also disclosed.

Abstract: In an earth boring bit of the type having a rotatable cone secured to a bearing shaft, an improved pressure compensating and relief system. A flexible diaphragm has an enlarge peripheral portion in an o-ring configuration sealingly secured in a compensator cavity to form a mud region and a lubricant region. A central portion of the diaphragm has a perforated and ridged protrusion extending into the mud region to form a self energizing area, exposed to the mud region, that seals the perforation when the pressure of the lubricant is less than or substantially equal that of the mud. A wall at the end of the compensator cavity surrounds the mud passage and engages an area around the protrusion when the diaphragm is fully extended by lubricant pressure build-up that exceeds the hydrostatic pressure. Thus, the resulting pressure differential opens the perforation, releases lubricant and relieves the build-up of lubricant pressure.

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 downhole drilling tool having a tubular stem connected to the drill string, and a tubular housing mounted concentrically and rotatably on the stem, forming an annular space between the housing and the stem. A plurality of bearings within the annular space support the housing against radial and longitudinal thrust loads. A plurality of seals within the annular space above and below the bearings form a lubricant chamber. The housing has a cylindrical lubricant passage extending between the lubricant chamber and the annular space outside of the lubricant chamber. A cylindrical piston is sealably slidable within the lubricant passage and responds to pressure of the drilling fluid entering the passage from the exterior of the housing to force lubricant out of the passage and into the lubricant chamber in order to replace lubricant which is lost therefrom. A downhole drilling motor is attached to the lower end of the housing.

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 rock bit having a cutter retained on an axle through an array of rolling members interposed within an interior annular space therebetween, and a passage defining a passage wall for inserting the rolling members from the exterior of the bit to the interior space. A plug for closing the passage, and retaining the members in the space is welded at an end adjacent the bit exterior and a contamination excluding snap ring is interposed between the plug and the passage wall for preventing weld slag or weld material from entering the passage.

Abstract: A sealed, pressure-equalizing lubrication system for a rotary rock bit is shown. The system includes a lubricant-filled container having an outlet and a portion of the container includes a flexible diaphragm. The container is mounted in a chamber in the journal axle portion of the bit, immediately adjacent and open to the sealed bearing cavity of the bit cutter, with the outlet disposed adjacent the cavity. A bleed hole is provided from the back face of the bit to the chamber adjacent the diaphragm causing the diaphragm to be responsive to the pressure of the external downhole fluid. The adjacency of the reservoir to the sealed bearing cavity permits the pressure of the lubricant adjacent the seal to be immediately responsive to the pressure of the downhole fluid at the diaphragm to prevent pressure differentials between the lubricant and the fluid at the seal.

Abstract: A pressure compensating lubricant reservoir system is disclosed for a rotary cone rock bit. The system comprises a two-piece canister and flexible boot, one side of the boot being vented to the dome area of the bit. An O-ring is utilized adjacent the reservoir cover cap to seal the lubricant within the reservoir cavity. In order to prevent damage to the O-ring, the cover cap part of the canister forms a circumferential groove therearound to accept the O-ring. An intermediate disc is trapped between the cover cap and the resilient boot and serves to close out the O-ring groove in the cover cap.With a prior art one-piece canister, the O-ring is put into position in a groove formed by the canister, followed by insertion of the canister into a lubricant cavity formed by the bit body. Damage to the O-ring often occurs when the outer peripheral edge of the O-ring passes by a cover cap snap ring retention slot at the reservoir cavity entrance.

Abstract: This invention discloses the utilization of a metal bellows in a grease reservoir cavity that is compressed during a rock bit grease filling process to create a positive pressure differential between the internal cavities in the bit and the outside atmosphere.