Abstract: This invention relates to multi-cone rock bits with three or more nozzles of varying length to affect different flow velocities from each of the nozzles. The nozzles at different lengths create a crossflow of fluid on a borehole bottom to lift detritus therefrom during rock bit drilling operations.

Abstract: There is disclosed a drill bit which is connectable to the lower end of a rotary drill string for use in drilling oil and gas wells as drilling mud is circulated downward through the string, out the bit, and upwardly within the annulus between the string and well bore so as to remove cuttings therefrom. The bit has cones which are mounted for rotation about thrust bearings which extend inwardly from the lower ends of legs which depend from a shank at the upper end of the bit body which is attached to the drill string.

Abstract: A mineral mining pick 1, a holder for such a pick, and the combination of such a pick with a holder 2. The pick has a head 3 with a cutting tip 5 and a shank 4 which is received in a shank socket 6 of the holder 2. Retaining means 7 is provided to releasably secure the pick in the holder. Extending through the pick is a water passage 11 which communicates with outlet ports 12 in the pick head for water flow to suppress dust and cool the tip 5. The passage 11 communicates with a socket 15 which mates with a tubular spigot 13 which is an extension to a fluid supply passage 2a in the holder 2. The spigot 13 is mounted by a resilient sleeve 22 in a tubular housing 19 by which it is removably retained in the holder 2. The sleeve 22 permits displacement of the spigot 13 to accommodate misalignment between the spigot and the socket 15 during coupling thereof as the shank is inserted into its socket 6.

Abstract: A rotary drill bit comprising a tubular strainer element co-axially arranged within the body of the bit and being provided with narrow axial slots arranged to prevent solid debris from passing to the nozzles of the bit. The self-cleaning ability of the strainer element is enhanced by increasing the bore of the strainer element in the region below the slots.

Abstract: An unsegmented structure for a rotary rock bit is disclosed comprising a one piece body of spring steel wherein individual journal members after being assembled with associated rotary rock cutters are interference fit to the free ends of downwardly directed leaf spring draw bars depending from the lower periphery of the pin end flange, to provide resistance to damage from transcient forces.A high capacity laminar flow hydraulic system which uses no nozzles delivers drilling fluid to the bore hole bottom and produces a low pressure region at that location via the Bernoulli effect to provide positive chip cleaning and flushing.

Abstract: The enhanced flow drill bit includes an upper body section having a bore therein and a lower body section formed integrally with the upper body section and including three passageways to transmit fluid outwardly of the drill bit body. The passageways, when intermittently open, transmit fluid flowing downwardly through the drill bit body and outwardly of the passageways to cause a cross flow in the area of the cone-type cutters. A rotor is mounted within a bore within the upper body section to intermittently open and close passageways to provide for an intensification of flow through the remaining open passageway to create high jet impact force of fluid flowing outwardly of the drill bit body to enhance cross flow and the removal of drill cuttings.

Abstract: This invention discloses a rolling cone drilling bit comprising a plurality of conical roller cutters having hard metal cutting elements thereon and being so positioned relative to each other that their rotational axes are offset from the rotational axis of the drill bit, and a drilling fluid nozzle system for directing a pressurized fluid stream across certain of the cutting elements and thereafter against the formation generally at the bottom of the well bore so that when the drill bit is used in its most advantageous areas, such as the soft, medium-soft and plastic formations, the nozzle system prevents "balling up" of the cutters and greatly increases the drilling efficiency of the bit.

Abstract: A drilling fluid nozzle for an earth boring bit is formed entirely of tungsten carbide, having hard-ground threads on its exterior for securing in the bit passage. The nozzle has an upwardly facing shoulder located below the threads which sealingly engages a downwardly facing shoulder formed in the bit passage. An O-ring seal is located above the threads.

Abstract: A rotary drill bit, for use in subsurface formations, comprises a bit body, a passageway for drilling fluid within the body, communicating with nozzles in the external surface of the body, preform cutting elements mounted on the body for cutting or abrading the formation, and a number of elongate fences upstanding from the external surface of the body to control the flow of fluid from the nozzles and past cutting elements. Each fence is resiliently deformable, for example being in the form of a brush having metal bristles, so that, in use, the free elongate edge of the fence is urged resiliently into contact with the surface of the formation being cut or abraded by the cutting elements. Since each fence is resiliently deformable it will at all times firmly engage the formation to provide an effective seal, regardless of variations in depth of cut of the cutting elements.

Abstract: A nozzle system for a rotary drill bit comprising a plurality of elongate nozzle members detachably secured in drilling fluid exit bores in a drill bit body, each nozzle member having passaging therein, the lower portion of which is angled relative to the longitudinal axis of the nozzle member, and a projection and recess arrangement for holding each nozzle member in its bore in a predetermined angular position for directing the drilling fluid to flow in a stream along a line at a predetermined angle and in a predetermined position relative to an adjacent roller cutter of the drill bit for improved cleaning of the cutting elements and the formation.

Abstract: Replaceable nozzles may be provided in a tungsten carbide drill bit manufactured by powder metallurgical infiltration techniques wherein at least one nozzle is threaded into a corresponding molded threaded bore in the bit. Despite the practical nonmachinability and brittleness of the tungsten carbide material, secure threaded insertion can be achieved if a squared thread design is used, and if the mold plug for forming the threaded bore is oversized to take into account the average variation in shrinkage in a bit formed by powder metallurgical infiltration techniques.

Abstract: A rotary drill bit comprising a bit body adapted to be secured to a drill string and to receive drilling fluid under pressure therefrom, the body having a plurality of nozzles for exit of the drilling fluid, and a plurality of depending legs at its lower end. The bit further includes a plurality of roller cutters, one for each leg, each cutter comprising a generally conical cutter body rotatably mounted on the respective leg, and a plurality of cutting elements thereon. The cutter body at its conical surface is formed of a material resistant to erosion by high drilling fluid which may impinge it.

Abstract: A rotary drill bit for drilling a well bore comprising a bit body adapted to be detachably secured to a drill string and receive drilling fluid under pressure therefrom and having a plurality of depending legs and a nozzle system for exit of drilling fluid from the bit body. The drill bit further comprises a plurality of roller cutters, each cutter having a generally conical roller cutter body rotatably mounted on one of the legs and a plurality of cutting elements on the cutter body.

Abstract: A nozzle assembly for an earth boring drill bit of the type adapted to receive drilling fluid under pressure and having a nozzle bore in the bottom thereof positioned closely adjacent the well bore bottom when the bit is in engagement therewith with the bore having inner and outer portions. The nozzle assembly comprises a generally cylindrical nozzle member of abrasion and erosion resistant material, selected from a plurality of such members, each being of the same outer diameter but having passaging therein of different cross-sectional area. The nozzle member is adapted to be fitted in the inner portion of the nozzle bore in sealing relationship therewith for forming a first seal for the nozzle assembly. The nozzle assembly further comprises a locknut, separate from the nozzle member, for detachably securing the nozzle member in the nozzle bore, formed at least in part of an abrasion and erosion resistant material.

Abstract: Methods and apparatus are provided for extending the effective length of a jet of fluid exiting a nozzle. An elongated jet extension member extends substantially axially outward from a nozzle outlet, and the jet of fluid flowing along and around the extension member tends to cling to the extension member thus decreasing the angle of divergence of the fluid jet.

Abstract: A rotary drill bit comprising a bit body having a chamber therein adapted to receive drilling fluid under pressure, a plurality of nozzles in communication with the chamber for exit of the drilling fluid, and a plurality of depending legs at its lower end, each having a bearing journal. The bit further includes a plurality of roller cutters, one for each leg, each cutter comprising a generally conical cutter body rotatably mounted on the bearing journal of the respective leg, and a plurality of cutting elements thereon. Each nozzle has an orifice in a position below the top of an adjacent roller cutter but above the central axis of the respective bearing journal at its inner end with respect to the bit body.

Abstract: A drilling sub is provided in a drill string above a drill bit. The drilling sub includes a nozzle oriented to eject drilling fluid from said drill string into an annulus between the drill string and a well bore hole at an elevation above the drill bit with a horizontal velocity component tangential to said annulus to thereby impart a swirling motion to drilling fluid in the annulus. This creates a vortex extending down to the drill bit to enhance the cleaning of cuttings from the bore hole and to reduce a pressure differential thereby increasing a penetration rate of the drill bit.

Abstract: A mineral mining pick 1, a holder for such a pick, and the combination of such a pick with a holder 2. The pick has a head 3 with a cutting tip 5 and a shank 4 which is received in a shank socket 6 of the holder 2. Retaining means 7 is provided to releasably secure the pick in the holder. Extending through the pick is a water passage 11 which communicates with outlet ports 12 in the pick head for water flow to suppress dust and cool the tip 5. The passage 11 communicates with a socket 15 which mates with a tubular spigot 13 which is an extension to a fluid supply passage 2a in the holder 2. The spigot 13 is mounted by a resilient sleeve 22 in a tubular housing 19 by which it is removably retained in the holder 2. The sleeve 22 permits displacement of the spigot 13 to accommodate misalignment between the spigot and the socket 15 during coupling thereof as the shank is inserted into its socket 6.

Abstract: In a drill bit comprising a body having a channel therethrough for carrying drilling fluid for injection into a bore hole through a nozzle at one end thereof and a cutting head mounted in the body and contacting the bottom of the bore hole. The improvement comprises at least one passage extending from the channel to a side portion of the exterior surface of the body wherein drilling fluid in the channel will flow through the at least one passage to the exterior of the body and form a fluid layer between the side portion of the body and the opposing side of the bore hole.

Abstract: A drilling sub is provided in a drill string above a drill bit. The drilling sub includes a nozzle oriented to eject drilling fluid from said drill string into an annulus between the drill string and a well bore hole at an elevation above the drill bit with a horizontal velocity component tangential to said annulus to thereby impart a swirling motion to drilling fluid in the annulus. This creates a vortex extending down to the drill bit to enhance the cleaning of cuttings from the bore hole and to reduce a pressure differential thereby increasing a penetration rate of the drill bit.

Abstract: A nozzle retention system is disclosed which serves to retain a jet nozzle in a drilling bit and also align the nozzle with respect to the bit cutters, said system utilizing a deformable pin and interacting channels in the nozzle and the bit nozzle bore.

Abstract: A method to retain a nozzle in a rock bit is disclosed for use particularly with air-type roller cone rock bits. A plastic nozzle body is formed with a multiplicity of radially disposed fins equidistantly spaced on the periphery of the nozzle body. A nozzle retention hole is formed in the body of the rock bit with a diameter slightly less than the diameter of the fins on the plastic nozzle. As the plastic nozzle body is forced into the nozzle retention hole, the fins deflect slightly in a downstream direction and "bite" against the nozzle retention walls formed by the bit body.

Abstract: An earth boring bit has a nozzle assembly with a wedging retaining ring and a crushed O-ring seal. The nozzle is located in a passage in the drill bit and bears against a shoulder. The retaining ring is secured by threads into the passage to tighten the nozzle against the shoulder. The retaining ring has a bore with an upper rim that encircles a conical section in the bore. The retaining ring conical section mates with a conical section formed on the exterior of the nozzle. The two conical sections wedge the nozzle in place when the retaining ring is tightened. An O-ring is located between the nozzle conical section, the wall of the passage and the upper rim of the retaining ring.

Abstract: A composite nozzle for a drill bit and a bore enlarging bit, the body of the nozzle, which is adapted to discharge water toward rotary cutters, being fabricated from a ceramic. The nozzle has a bottom surface which is provided with a high-impact metal plate, and a circumferential wall portion also provided with a reinforcing plate.

Abstract: A drill bit and a method for deep-hole drilling in which the drill bit has mechanical cutting means located on its lower cutting face for cutting a solid surface upon rotation of the bit and a plurality of cavitating liquid jet nozzles spaced around the face of the bit to assist in the drilling action, the nozzles being located so as to discharge a plurality of downwardly directed and concentric liquid jets that cavitate to fracture the surface to be drilled in a series of non-overlapping slots as the bit is rotated.

Abstract: A flow cavitation insert device is adapted to be positioned adjacent a conventional nozzle, the nozzle then is converted to a cavitation nozzle for a rock bit. The cavitation device is designed to operate with hydraulic drilling mud and comprises a circular adapter plate with a concentric orifice formed thereby. A cavitation-inducing, flow restrictor crossbar radially intersects the center of the orifice formed by the plate. The crossbar is secured to the circular disc where the opposite ends of the flow restrictor come in contact with an axially aligned wall forming the inside diameter of the orifice.

Abstract: A valve-nozzle assembly is disclosed for use in a rock-drilling bit, which assembly utilizes a backflow valve with a replaceable nozzle insert.

Abstract: Disclosed is a drill bit with an eduction jet which discharges drilling mud upwardly through nozzles having wedge shaped apertures oriented such that the wedge shape is tangential to the central axis about which the drill bit rotates. Expelled mud projects a wedge shaped dynamic stream of mud which retains the definition as an eductive column which rotates with the drill bit and therefore has relative motion revolving transverse to the hydrostatic column bearing upon the bit. Throughout the regions in which it retains definition, the eductive column creates a low pressure zone immediately behind it and the low pressure zone enhances the ability of flushing jets to remove cuttings from the bottom of the borehole by drawing the cuttings above the drill bit. The manufacture of drill bits with wedge shaped eduction jets is also disclosed, including the manufacture by modification of conventional tri-cone bits.

Abstract: The present invention discloses a large diameter oil well drilling bit which utilizes a unique cast body upon which are secured a plurality of cutting assemblies comprising a leg, a bearing journal and a rolling cutter mounted on the bearing journal.

Abstract: A drill bit is disclosed for drilling large diameter shafts. The drill bit comprises a main bit body having a plurality of cutter assemblies rotatively mounted on the lower side thereof. The cutters contact and disintegrate the earth formations at the bottom of the shaft, thereby creating rock chips. The cutters are strategically located along arcuate paths and extending generally from the bit gage or periphery to the center of the bit. An arcuate channel is formed by the bit body to house the cutters and to provide a high velocity flow path for drilling fluid which engulfs all the cutters and flushes the rock chips away during operation of the bit. Drilling fluid containing rock chips enters the drillstring at the center of the bit body and is then pumped up and out of the shaft being drilled.

Abstract: A rotary drill bit for drilling a bore hole in the surface of the earth is provided in which the drill bit comprises a body having a duct therethrough for carrying drilling fluid. A conical cutting head having an axis at an acute angle with respect to the axis of the drill bit is mounted in the cutting head. An elongated nozzle is positioned at the end of the duct for injecting the drilling fluid into the bore hole. The nozzle has an opening which opens into the bore hole wherein the longitudinal center line of the opening follows the locus of the mid-point between the side wall of the bore hole and the outermost circumference of the cutting head. Drilling fluid injected through the nozzle removes detritus from between the teeth and the cutting head at the bottom of the bore hole. The body of the drill bit has a first portion having a truncated conical surface with the axis of the truncated cone coinciding with the axis of the cutting head.

Abstract: A rotary drill bit and drill bit cone for drilling bore holes through earth formations. The rotary drill bit includes a generally hollow body portion having a plurality of longitudinally extending shanks which terminate with inwardly directed spindles. A cutting cone is mounted upon each shank spindle and is provided with a plurality of elevated, primary, land areas which extend in a spiral pattern from the apex of the cone to the base. In a preferred embodiment, a plurality of elevated, secondary, land areas spiral from points intermediate the apex and base of the cone to the base of the cone in an alternate arrangement with the primary land areas. Cutting teeth are mounted upon each of the primary and secondary spiral land areas for digging into the earth formations during a drilling operation and in a preferred embodiment comprised partial disc shaped members which are embedded into the land portions of the spiral drill cone.

Abstract: An earth boring drill bit has a drilling fluid nozzle with features that protect the nozzle retaining ring from erosion and avoid pressing cracks. The drill bit has a passage with at least one outlet and a nozzle located at the outlet for discharging fluid. The nozzle has a shell mounted in the outlet and retained by a retaining ring. An insert is bonded inside the shell. The insert is of tungsten carbide or ceramic for resisting erosion. The insert has an extended portion that extends below the rim of the outer member for protecting the retaining ring from flowing drilling fluid.

Abstract: Disclosed herein is a large diameter earth boring bit with improved nozzle placement. The bit is of the type having a cutter support with several rotatable cutters mounted below. The bit is connected to a string of pipe having an input and a return flow passage. Nozzles are located on the cutter support for the discharge of fluid onto the borehole bottom to sweep cuttings into an intake port in the cutter support. An outer zone nozzle is located at the periphery of the cutter support for cleaning the gage area of the borehole.Several inner zone nozzles are spaced between the periphery and the intake port. The inner zone nozzles are positioned so that the area of influence of each nozzle overlaps with its next inward nozzle. This creates a continuous stream that entrains cuttings and sweeps them to the intake.

Abstract: Dual flow passage drilling means includes a dual flow passage sub and a dual flow passage bit. The bit has a threaded tubular pin and a flat seal shoulder there around, adapted to make a rotary shouldered connection with a central box at the lower end of the sub.The bit includes a cylindrical body with a central flow passage and three circumferentially spaced off-axial holes centered 120 degrees apart providing outer fluid passage means communicating through the bit shoulder with the sub's annulus. Beneath the body are earth formation reducing means, including three jet nozzles connected to the off-axial holes. The earth formation reducing means further includes three drilling cones rotatably mounted on three legs depending from the body. The legs are centered 120 degrees apart, for example midway between the nozzles. The diameter of the earth bore is determined by the locus of the outermost parts of the cones as the cones rotate at the bottom of the bore.

Abstract: A rock bit used for drilling with air as the circulating fluid, and a centrifugal separator to filter liquid and other contaminants from the air diverted to the bit bearings. The filter generates a fluid vortex with radial vanes, each having plural pitches, located within the shank of the bit. Bearing coolant passages, located beneath the separator, receive filtered air from a central, filtered air location. The vortex centrifugally forces the water and other contaminants outwardly into nozzle passages that direct fluid toward the bottom of the borehole.

Abstract: This drill bit comprises a plurality of rollers provided with cutting teeth or inserts.At least one vertical fluid flushing jet is directed towards the hole bottom between two adjacent rollers and at least one upwardly directed education jet is created. The nozzle delivering the flushing jet opens at a distance from between 1/3 H and 4/5 H from the hole bottom, H being the height of the cutters measured in a direction parallel to the bit axis.

Abstract: This drill bit comprises a plurality of rollers provided with cutting teeth or inserts.At least one upwardly directed eduction jet is created and the bit comprises at least one nozzle located between two adjacent rollers and creating at least two fluid jets respectively directed towards these two adjacent rollers.

Abstract: A drilling bit for drilling earthen material such as an oil well rotary cone drilling bit, which includes means for preventing foreign particles such as sand, rock cuttings, etc., from reaching the rotational bearings of the bit cones. This end result is principally achieved by means of a centrifugal slinger disc or wall which is positioned in external concentricity with the drill bit cone bearing, and operates to drive granular particles away from the bearings, thereby preventing such particles from reaching these bearing surfaces. The granular particles are driven by the slinger action through a series of apertures forming a channel running out to a peripheral region of the bit cones. A channel continuation is also provided for lubricating fluid, which may comprise ambient water or oil placed in chambers surrounding the bearings, this channel providing access for such lubricating fluid inwardly to the bit cone bearings.

Abstract: A rotary drilling tool has a plurality of rollers, each of which is provided with a specific pair of jets comprising a flushing jet having a downwardly directed component and an upwardly directed eduction jet, these jets being formed on both sides of the plane defined by the bit axis and the roller axis, and the flushing jet being inclined by at least 20.degree. on said plane and substantially tangent to the active part of the roller.

Abstract: A sweep pickup for a large diameter drill bit is disclosed. The drill bit includes a main bit body having a plurality of roller cutters rotatively mounted thereon. Drilling fluid is pumped down the annulus of the well bore, across the face of the bit and up a central passage located within the bit. A sweep pickup is connected to the central passage and includes a lower inlet having a semicylindrical chamber mounted adjacent the trailing side thereof. A flexible wiper blade is located on the leading edge of the sweep pickup tube adjacent the inlet and is adapted to contact the base of the well bore in order to agitate and project the drilled cuttings into the flow of the drilling fluid. The wiper blade also functions to block the fluid flow to the inlet of the sweep pickup from the leading side thereof, thereby creating a unidirectional fluid flow to the inlet of the sweep pickup from the trailing side thereof.

Abstract: An improved sweep pickup for large diameter bits is disclosed in which the flow rate of drilling fluid through the pickup tube is constant, thereby enhancing its lifting capacity. The sweep pickup comprises an elongated tube extending radially across the bottom face of the drill bit. The pickup tube is truncated longitudinally on the bottom side thereof by a horizontal plate having the pickup inlet opening formed therein. The plate truncates the tubular portion of the pickup at an angle to provide an increasing vertical cross-section in the direction of the pickup outlet which is toward the center of the drill bit body. In the preferred configuration, the vertical cross-sectional area with the pickup tube at any point is equal to the area of the inlet opening from that point radially outward to the outer extremity thereof. As a result, the flow rate of drilling fluid through the sweep pickup is constant and equal to the flow rate through the interior of the drill string.

Abstract: A raise bit is disclosed for enlarging a pilot hole into a large diameter hole by disintegrating the earth formations surrounding the pilot hole. The raise bit includes a removable drive stem for enabling the raise bit to be transported through small drifts. The drive stem is attached to a thrust bearing plate which, in turn, is interconnected to a main bit body. The bit body extends around the drive stem and includes a plurality of rolling cutters for contacting and disintegrating the earth formations surrounding the pilot hole. The interconnection between the thrust bearing plate and the bit body is accomplished by means of an annular shock absorbing ring made of polyurethane. Means are also provided to transport fluid from the interior of the drive stem to contact the rolling cutters on the bit body. These means comprise a fluid passage way extending through the interior of the drive stem.

Abstract: In a drilling bit, a cone shaped cutter is rotatably mounted on a spindle on anti-friction bearings and on a friction bearing in the nose of the spindle. A passage is formed in the exterior cylindrical surface of the spindle nose in the load bearing zone. This passage is connected to a radial passage on the end or thrust bearing surface of the spindle, and the center of the thrust bearing surface communicates with a weep hole in the nose of the cutter. Cooling fluid is ducted through the spindle and through these passages to provide cooling directly in the area where the generated heat is the greatest and fluid flow a minimum in previous constructions.

Abstract: Method and apparatus are disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe, through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. After the cutters are fully expanded, additional air is utilized to clean and cool the cutters. Air is returned through the inner pipe of the dual concentric pipe string. A venturi device is utilized to induce return flow through the inner pipe during enlargement of the hole and to vacuum residue when enlargement is completed. The dual concentric pipe string is made up of lengths of pipe providing threaded, sealed joints.

Abstract: This invention teaches the use of one or more cavitation inducing nozzles in combination with conventional nozzles for rock bits. The cavitation nozzles enhance the drilling rate by rapidly removing cuttings from the hole bottom. Cavitation from a cavitating nozzle positioned on one side of the bit reduces the pressure thereby inducing drilling mud at higher pressure passing through an opposing non-cavitative nozzle to move across the rock-tooth interface. The resultant cross-flow rapidly removes the cuttings from the hole bottom.

Abstract: This invention teaches the use of cavitation inducing nozzles in combination with rock bits. The cavitation nozzles enhance the drilling rate by creating catastrophic implosion waves which erode solid material at the bottom of the hole while reducing the localized pressure at the rock tooth interface. Localized pressure reduction reduces the tendency for the cuttings to adhere to the bottom of the hole due to differential pressure.

Abstract: Means for emitting high-pressure jets of fluid such as water, and mechanical rock breaking wheels, are positioned on a rotary drill bit for cooperatively cutting an axially extending bore hole through earth material. A center core opening is cut into the drill face material of the bore hole by a jet of fluid crossing the axis of the bore hole at an acute angle. The material of the drill face annularly surrounding the center core opening is removed by cutting concentric slots in the material and by applying radially inward directed force for breaking each ring defined by the slots cut. At any given axial position or level, the slots are cut and the rings are broken in sequence from the radially innermost position to the radially outermost position of the bore hole.

Abstract: A drilling bit for drilling earthen material such as an oil well rotary cone drilling bit, which includes means for preventing foreign particles such as sand, rock cuttings, etc., from reaching the rotational bearings of the bit cones. This end result is principally achieved by means of a centrifugal slinger disc or wall which is positioned in external concentricity with the drill bit cone bearing, and operates to drive granular particles away from the bearings, thereby preventing such particles from reaching these bearing surfaces. The granular particles are driven by the slinger action through a series of apertures forming a channel running out to a peripheral region of the bit cones. A channel continuation is also provided for lubricating fluid, which many comprise ambient water or oil placed in chambers surrounding the bearings, this channel providing access for such lubricating fluid inwardly to the bit cone bearings.

Abstract: A three cone rock bit includes an improved circulation system for drilling fluid which increases the horizontal flow vector of the fluid adjacent the bottom surface of the hole being drilled. A pair of nozzles, located near the hole perimeter and between adjacent pairs of drilling cones, inject drilling fluid at one side of the hole. An extended pickup tube terminating between the remaining pair of drilling cones and close to the bottom of the hole being drilled channels fluid from the bottom of the hole to the annulus between the hole and the drill string.