Abstract: Apparatus and methods for preparing a blast hole in a rock face during a mining operation are disclosed. An exemplary method comprises: deploying a first tool toward the blast hole in the rock face via a common tool outlet of a feed unit using a first tool station of the feed unit; retracting the first tool from the common tool outlet using the first tool station of the feed unit and retaining the first tool in the first tool station; and while the first tool is retained in the first tool station, deploying a second tool toward the blast hole in the rock face through the common tool outlet of the feed unit using a second tool station of the feed unit.

Abstract: A tool bit assembly includes a shank having an elongated shaft, an intermediate portion extending from the shaft, a head extending from the intermediate portion, and a tool portion extending from the head. The assembly includes a retainer with a body defining a hollow shaft configured to receive at least a portion of the elongated shaft of the shank therethrough, and a washer defining an opening extending from a first end to a second end of the washer, and the washer having at least a first step and a second step. The opening of the washer is configured to receive at least a portion of the intermediate portion of the shank therethrough. The first step is configured to abut a bottom surface of the head of the shank, and the second step is configured to abut a first shoulder of the intermediate portion of the shank.

Abstract: A washerless cutting tool assembly includes a cutting tool holder and a rotatable cutting tool at least partially disposed within the cutting tool holder. The cutting tool holder includes an alignment feature in the form of a protrusion at an axial forward end and a groove at an axial rearward end of the head portion of the rotatable cutting tool. The groove is capable of receiving the protrusion of the cutting tool holder to align the central, longitudinal axis of rotatable cutting tool with the central, longitudinal axis of the cutting tool holder. The cutting tool assembly further includes a limited rotated feature in the form of a braking ring disposed within an annular groove and a retainer ring disposed over the braking ring.

Abstract: An end surface-contact mechanical seal providing a shielding seal between a liquid area (A) and an atmospheric area (B) by a relative rotation, while in a contact state, of opposing end surfaces (4a, 6a) of a case-side sealing ring (4), which is fixed to a seal case, and a ceramic shaft-side sealing ring (6), which is held on the sleeve (22) of a rotary shaft (2). A rubber O-ring (5) is installed between a sealing ring-side seal surface (63a), which is formed on the inner peripheral surface of the shaft-side sealing ring (6), and a shaft-side seal surface (22c), which is formed on the outer peripheral surface of the sleeve (22), so as to be relatively movable in the axial direction while sealing the surfaces. A diamond film (14a) is formed over the entire surface of the sealing ring-side seal surface (63a).

Abstract: A disclosed example embodiment includes a drill bit used to form wellbores in subterranean formations. The drill bit includes a drill bit body for coupling to a lower end of a drill string. The drill bit body includes at least one support arm having an inwardly extending journal with a journal bearing having at least one radially reduced pocket extending at least partially circumferentially around the journal bearing including a load side of the journal bearing. At least one rotary cutter assembly is rotatably mounted to the journal. A plurality of cutting elements is disposed on the at least one rotary cutter assembly. At least two independent hardmetal pads are positioned within the at least one radially reduced pocket such that the hardmetal pads have a gap disposed therebetween.

Abstract: The disclosure relates to a bore tube for a pressure compensation system in a roller cone drill bit. The bore tube includes a bit body having at least one support arm extending therefrom, a lubricant chamber in each support arm, a bore in each support arm extending from to the lubricant chamber to an exterior surface of each support arm, a tube in the bore of each support arm, and a floating bead in the tube and operable to move axially within the tube in response to a pressure of the environment surrounding the roller cone drill bit.

Abstract: A drill bit for directional drilling includes a main body and a wear component. The main body is unitary and formed of a first material. The main body includes opposed outer surfaces and a periphery extending between the opposed surfaces. The wear component is unitary and is formed of a second material that is harder than the first material. The wear component comprises a retention portion and a wear portion. The retention portion is positioned within the first material of the main body. The retention portion includes opposed retention surfaces that, moving in a direction inward from the periphery of the main body, taper apart from each other toward the opposed outer surfaces of the main body. The wear portion extends outward from the retention portion relative to the periphery of the main body. The wear portion is substantially planar and is configured to form an outer wear edge.

Abstract: A shifting tool for use in shifting axial position of a shiftable element in a well. The tool comprises a linkage mechanism configured to translate an independent axial force into a dedicated radial force applied to expansive elements thereof. Thus, the elements may radially expand into engagement with the shiftable element free of any substantial axial force imparted thereon. As such, a more discretely controllable shifting actuation may be attained, for example, as directed from an oilfield surface. Indeed, real-time intelligent feedback may also be made available through use of such elements in conjunction with the noted linkage mechanism.

Abstract: An earth boring bit with sealed cutter bearings has lubricant flow passages which extend from an interior cavity of the bit body to spaces located between bearing shafts and rotary cutters. A lubricant compensator has an elongate body defined by a tube which has a first end disposed in one of the flow passages and a second end which extends into the interior cavity. A piston is initially disposed in the second end, biased to apply pressure to lubricant located in the flow passages. The first end has a section for receiving the piston when lubricant is expelled from within the tube. Apertures extend through a sidewall of the tube, spaced apart from the section in the first end and in fluid communication with the flow passages. The apertures, the flow passages, and the spaces located between bearing shafts and rotary cutters are sized for passing drilling fluid.

Abstract: The present invention relates to apparatus and methods for remotely adjusting the drill bit hydraulic horse power per square inch (HSI). Varying the nozzle geometry remotely without the need to pull the drill string outside the hole has obvious advantage. Changing the nozzle flow geometry results in changing the nozzle HSI, which is beneficial to optimize drilling a well having different rock formations. The drill bit nozzle geometry of the present invention can be varied by causing a change of at least one physical property of the environment. The variable geometry nozzle is not limited to drill bit, it can be placed within the inner flow passage or between the inner flow passage and annular flow passage for controlling flow profile within a wellbore, a tubular string or a flow conduit.

Abstract: The present invention includes compositions and methods of supplying a corrosion inhibitor including placing a corrosion inhibitor attached to a nanostructure carrier, placing the nanostructure carrier containing the corrosion inhibitor at a location and the nanostructure carrier is capable of releasing the corrosion inhibitor.

Abstract: A drill bit of the type used to drill a wellbore in the earth can comprise a bore formed in the drill bit, and a plug sealingly and reciprocably disposed in the bore, whereby the plug prevents fluid communication between sections of the bore in the drill bit. The plug can comprise a spherically-shaped member. The plug can comprise a floating plug sealingly and reciprocably disposed in the bore, whereby pressure in the different sections of the bore on respective opposite sides of the plug is substantially equalized.

Abstract: A device for supplying lubricant to a lubrication point in a machine, a tunnel boring machine, for example, includes a lubrication pump unit and a control unit. The lubrication pump unit is configured to supply a quantity of the lubricant to the lubrication point, and the control unit is configured to regulate the quantity of lubricant based on a sensor measurement signal. The sensor measurement signal may be based on a temperature measured in a region of the lubrication point, a pressure measured in a region of the lubrication point, a measured viscosity of the lubricant, a measured dielectricity of the lubricant, a measured water content of the lubricant, a vibration intensity measured at a part of the machine, or a measured rotational speed of a part of the machine.

Abstract: A drill bit of the type used to drill a wellbore in the earth can comprise a bore formed in the drill bit, and a plug sealingly and reciprocably disposed in the bore, whereby the plug prevents fluid communication between sections of the bore in the drill bit. The plug can comprise a spherically-shaped member. The plug can comprise a floating plug sealingly and reciprocably disposed in the bore, whereby pressure in the different sections of the bore on respective opposite sides of the plug is substantially equalized.

Abstract: A wellbore tool includes a non-hydrocarbon-based grease disposed between a first component and a second component. The grease remains substantially impermeable to hydrocarbons at temperatures up to at least about 150° C. and possibly up to at least about 200° C., and pressures up to at least about 27 MPa and possibly to at least about 50 MPa. Methods of forming such wellbore tools include selecting a grease to comprise a non-hydrocarbon-based grease that remains at least substantially impermeable to hydrocarbons at temperatures up to at least about 150° C. and possibly up to at least about 200° C., and pressures up to at least about 27 MPa and possibly to at least about 50 MPa; and disposing the grease at an interface between a first component of a wellbore tool and a second component of a wellbore tool.

Abstract: A pressure compensation assembly for a drill bit having a cavity to receive the pressure compensation assembly, a mud port connected to the cavity, and a lubricant passageway connected to the cavity, is disclosed. The pressure compensation assembly includes a relief mechanism having a selected operating pressure. The pressure compensation assembly is movable from a first position to a second position within the cavity. The pressure compensation assembly may receive lubricant at a pressure exceeding the selected operating pressure to permit the flow of lubricant into the lubricant passageway while substantially preventing the release of lubricant into the mud port while in the first position. The pressure compensation assembly is operable to limit a pressure differential within the drill bit while in the second position.

Abstract: Surface texturing is employed to modify the topography of one or more surfaces (radial or cylindrical) of the bearing system for a roller cone rock bit. The surface texturing results in a dimpled surface which retains additional lubricant helpful in reducing friction in the boundary and mixed lubrication regimes. Shot peening is disclosed as one method for texturing the desired surface.

Abstract: A drill bit may include a bit body rotatable about a longitudinal axis and having, at one end, a connection for securing the drill bit to a drill string and having a face opposite the connection end; and a plurality of cutting structures having at least one fixed cutting structure disposed on the bit body face and at least one cutting body rotatably attached to the face of the bit body; wherein, in a rotated view of the plurality of cutting structures into a single plane, there is substantially no radial overlap between at least one fixed cutting structure and the at least one cutting body.

Abstract: A bore hole rotary reamer includes a body having cutters rotatably mounted by one or more respective spindles. A bearing region is formed on the spindle. At least one annular seal prevents ingress of contaminant to the bearing region. A circumferential void is formed adjacent the seal. At least one passageway extends in an axial direction of the spindle to the circumferential void and a piston movable in the passageway in response to supply of pressure to an outer side of the piston from the environment which surrounds the reamer. The piston transfers pressure to fluid in the cylindrical passage on an inner side of the piston to supply pressure to the circumferential void and thereby to the seal. The pressure is substantially determined by the pressure of the environment surrounding the reamer.

Abstract: The present invention includes compositions and methods of supplying a corrosion inhibitor including placing a corrosion inhibitor attached to a nanostructure carrier, placing the nanostructure carrier containing the corrosion inhibitor at a location and the nanostructure carrier is capable of releasing the corrosion inhibitor.

Abstract: An earth bit includes a cutting cone mounted to a lug to form a bearing cavity. A valve is in fluid communication with the bearing cavity and a bit chamber, wherein the valve includes a diaphragm with an aperture. The aperture is repeatably moveable between open and closed conditions in response to a pressure difference between the material in the bearing cavity and bit chamber.

Abstract: A pressure compensation assembly for a drill bit having a cavity to receive the pressure compensation assembly, a mud port connected to the cavity, and a lubricant passageway connected to the cavity, is disclosed. The pressure compensation assembly includes a relief mechanism having a selected operating pressure. The pressure compensation assembly is movable from a first position to a second position within the cavity. The pressure compensation assembly may receive lubricant at a pressure exceeding the selected operating pressure to permit the flow of lubricant into the lubricant passageway while substantially preventing the release of lubricant into the mud port while in the first position. The pressure compensation assembly is operable to limit a pressure differential within the drill bit while in the second position.

Abstract: An elastomeric seal ring is located between each bearing pin and each cone of an earth-boring bit. An excluder ring or band is imbedded within the inner diameter of the seal ring. A portion of the inner diameter of the seal ring as well as the excluder ring are in dynamic sealing contact with the bearing pin. The excluder ring may be harder and more wear resistant than the seal ring. The excluder ring may have lubricating properties. An outer excluder ring may be located on the outer diameter of the seal ring for engaging the cone to resist rotation.

Abstract: A method for lubricating a diamond bearing system of a downhole well tool involves dispensing a polyol lubricant for the reduction of friction between the two diamond surfaces. The lubricant forms a reduced friction surface film on the diamond. The polyol lubricant may be mixed with water. The polyol lubricant may contain ethylene glycol, glycerol, or a combination with water.

Abstract: A lubricating nutating single cone drill bit 10 includes bit shank 12 with an axially skewed journal 18 rotatably retaining cutter body 22. Bearings (26, 28, 30, 32) enable rotation of the cutter body 22. Lubrication flows to a gap between the axially skewed journal 18 and cutter body 22 from lubricant chamber 76 having plunger 80 acted on by an annulus fluid, the gap bounded by first 66 and second 68 radial dynamic seals. A fluid passage 90 extending through the bit 10 communicates with fluid inlet port 88 on the proximal end 16 of the bit shank 12. Fluid passage 90 also communicates with a first fluid outlet port 98 on the distal end 36 of the axially skewed journal 18 and with a second fluid outlet port 94 formed on a lateral portion of bit shank 12.

Abstract: An arrangement for replenishing lubricating grease in drill cutters (3) that include a conical outer barrel (7) which is rotatable about a shaft (5) disposed centrally in the cutter, wherein there is provided in the cutter shaft (5) a passageway (16) that extends along the shaft from the cutter end of largest diameter and that connects with a transverse passageway (18) which opens into a bearing-accommodating space (13) in the cutter for delivering lubricating grease to the space (13), and wherein a lubricating nipple (19) is provided on the cutter end wall of largest diameter and functions to allow lubricating grease to be released from the bearing-accommodating space (13).

Abstract: A high-temperature lubricant is shown and described. The lubricant includes a base stock and about 1 to about 20 weight percent zirconium 2-ethylhexanoate. The lubricant may also include about 1 to about 9 weight percent bismuth 2-ethylhexanoate.

Abstract: A lubricating grease is specific for a rock bit for drilling subterranean formations. The rock bit body includes a plurality of journal pins, each having a bearing surface, with a cutter cone mounted on each journal pin and also including a bearing surface. A grease reservoir provides lubricating grease to such bearing surfaces. The grease composition adjacent the bearing surfaces comprises a lubricating base oil, sufficient thickener and additives in the base oil to form a rock bit grease, and an effective amount of polarized graphite.

Abstract: A roller cone drill bit is disclosed which includes at least one roller cone rotatably mounted to a bit body. The bit body includes therein a lubricant reservoir adapted to supply lubricant to bearings on which the roller cone rotates about the bit body. The bit includes a sensor adapted to detect drilling fluid contamination of the lubricant. The bit includes a processor/transmitter operatively coupled to the sensor and adapted to communicate signals corresponding to detected contamination.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and a conduit for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and the means for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and a conduit for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

Abstract: A drill bit has a plurality of air tubes extending into the bowl for separating entrained debris and liquids from air flow used to clean and cool bearings in the cutters of the bit. The air tube is assembled from a tube and a cap. The tube has open ends and a plurality of openings through the sidewall of the tube for allowing air to flow through the openings while preventing large debris from entering the tube. The lower end of the tube is inserted into an inner portion of a fluid passage, and the cap is secured to the upper end of the tube. The cap is removable for providing access to the interior of the tube when necessary to dislodge debris from within the tube.

Abstract: A roller cone drill bit is disclosed which includes at least one roller cone rotatably mounted to a bit body. The bit body includes therein a lubricant reservoir adapted to supply lubricant to bearings on which the roller cone rotates about the bit body. The bit includes a sensor adapted to detect drilling fluid contamination of the lubricant. The bit includes a processor/transmitter operatively coupled to the sensor and adapted to communicate signals corresponding to detected contamination.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone, an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole and an annular space disposed between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity and means for permitting the flow of fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and the means for permitting the flow of fluid may further permit the flow of fluid from the borehole to the annular space.

Abstract: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone and an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole. An annular space is defined between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity. The seals are configured to allow the passage of a fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for fluid from the borehole to the annular space can be included.

Abstract: A solid lubricant is added to the internal passages of an air cooled bit such that the air erodes, or ablates, the solid lubricant into the air stream. Compressed air travels down the drill stem to the bit. The air passes through an air tube into the main air passage where the solid lubricant has been placed. As the air passes the solid lubricant, it erodes the solid lubricant. The solid lubricant particles ablated into the air stream travel through the ball passage into the journal air passage and out to the bearing surfaces between the cutter and the journal. The air stream both cools the surfaces and deposits the solid lubricant to reduce the friction between the bearing surfaces.

Abstract: A sealing structure for a rock drill bit includes an elastomeric diaphragm for installation in the drill bit so as to separate grease from drilling mud. The diaphragm has an aperture extending through it, and a plug is disposed in the aperture so as to form a mechanical seal with a wall of the aperture. The plug has a channel therethrough which is normally held sealed by a face of the aperture in the diaphragm. If the pressure of the grease exceeds pressure in mud on the other side of the diaphragm by more than a critical value, the diaphragm aperture deforms and allows grease to move through the plug channel and escape. The critical value can be varied by using, with the same diaphragm, plugs having different numbers, sizes and axial positions of plug channels.

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 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 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: A drill bit for use in a borehole at least partially containing drilling fluid includes a bit body having at least two bit components, including at least one leg, the leg having a journal segment, and a roller cone rotatably mounted upon the journal segment and forming at least one bearing cavity therebetween. Also included is an annular primary seal disposed between the leg and the roller cone and an annular secondary seal disposed between the leg and the roller cone and between the annular primary seal and the borehole. An annular space is defined between the annular primary seal and the annular secondary seal, the annular space at least partially containing fluid and being in substantially absolute fluid isolation from the bearing cavity. The seals are configured to allow the passage of a fluid from the annular space to the borehole. The annular secondary seal may be primarily elastomeric and a passage for fluid from the borehole to the annular space can be included.

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 rolling cutter drill bit comprises a main body and three depending legs, each leg having a cantilevered bearing spindle on which a rolling cutter is rotatably mounted. Bearings located between the cutter and spindle include a radial bearing, and a thrust bearing configured to carry onward thrust loads from the cutter onto the spindle. A bearing seal defines an enclosed region between the cutter and the spindle in which the bearings are located, and a pressure balanced lubricant delivery system within the spindle delivers lubricant to the bearings. The lubricant delivery system includes a non-return valve to allow lubricant to flow into the area of the enclosed region containing the thrust bearing and the area is bounded by a tortuous flow path which allows a more restricted flow of lubricant out of the thrust bearing area and into another area of the enclosed region, without pressurizing the bearing seal.

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: An earth-boring bit has a bit body, at least one cantilevered bearing shaft, including a base and a cylindrical journal bearing surface extending inwardly and downwardly from the bit body, and at least one cutter mounted for rotation on the cylindrical journal bearing surface of the bearing shaft. A seal assembly is disposed between the cylindrical journal bearing surface and the cutter proximally to the base of the cantilevered bearing shaft. The seal assembly includes at least one rigid seal ring having a seal face in contact with a second seal face. A selected one of the seal faces is at least partially formed of a hard ceramic type material with the other seal face being formed of a relatively softer material to provide improved wear resistance for the seal assembly.

Abstract: A rolling cutter drill bit comprises a main body and three depending legs, each leg having a cantilevered bearing spindle on which a rolling cutter is rotatably mounted. Bearings located between the cutter and spindle include a radial bearing, and a thrust bearing configured to carry onward thrust loads from the cutter onto the spindle. A bearing seal defines an enclosed region between the cutter and the spindle in which the bearings are located, and a pressure balanced lubricant delivery system within the spindle delivers lubricant to the bearings. The lubricant delivery system includes a non-return valve to allow lubricant to flow into the area of the enclosed region containing the thrust bearing and the area is bounded by a tortuous flow path which allows a more restricted flow of lubricant out of the thrust bearing area and into another area of the enclosed region, without pressurizing the bearing seal.

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 shaft boring bit has a bit body with at least one saddle member secured to the bit body. The saddle receives and supports the ends of a journal member. A cutter is mounted for rotation on the journal member and an anti-friction bearing is disposed between the cutter and the journal and secures the cutter on the journal member. Seal means are provided between the cutter and the journal member to retain lubricant in the anti-friction bearing. A bearing loading passage is formed in the journal member for loading at least a portion of the anti-friction bearing between the cutter and the journal member. A lubricant compensator assembly is removably disposed in a lubricant compensator recess formed at one end of the journal. The lubricant compensator is in fluid communication with the anti-friction bearing and includes a rigid ball plug member, which obstructs the bearing loading passage and abuts the portion of the anti-friction bearing to retain the bearing between the cutter and journal.