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 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 a canister or the like, which can be provided with a venting 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 roller cone drill bit is disclosed which includes a bit body having at least one leg depending from the bit body. The leg has a journal formed on it at a lower end. The bit body includes an air channel extending at least from an interior of the bit body to the seal area of the journal. A roller cone is sealingly, rotatably mounted on the journal. The cone has a plurality of cutting elements disposed on it. The bit includes a backflow valve disposed in the bit body, so that an intake end of the air channel is disposed upstream of the backflow valve. In one embodiment, the backflow valve is disposed in a connection end of the bit body, and the air channel includes a flow tube extending from the air passage in the bit body to the backflow valve so that its intake end is upstream of the backflow valve.

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 drill bit for use in an earthen annulus that contains loose particles is connected to a fluid supply source and includes a bit body having at least one journal segment and at least one fluid conduit in fluid communication with the fluid supply source. A roller cone is rotatably mounted upon the journal segment and forms at least one bearing cavity therebetween. Annular primary and secondary seals are disposed between the roller cone and the bit body and between the bearing cavity and the earthen annulus. An air groove is provided around at least a portion of the cone or leg between the primary seal and the earthen annulus. The groove circumscribes less than the entire circumference of the groove or leg, and in preferred embodiments includes an exit port and/or a diversion plug. Both the exit port and the diversion plug help prevent the groove from becoming plugged with debris.

Abstract: A drill bit for use in an earthen annulus that contains loose particles is connected to a fluid supply source and includes a bit body having at least one journal segment and at least one fluid conduit in fluid communication with the fluid supply source. A roller cone is rotatably mounted upon the journal segment and forms at least one bearing cavity therebetween. An annular primary seal is disposed between the roller cone and the bit body and between the bearing cavity and the earthen annulus, and an annular gap is disposed between the annular primary seal and the earthen annulus. The annular gap is in fluid communication with the fluid conduit and the earthen annulus. An annular secondary seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annulus to the annular primary seal.

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 sealed-bearing drill bit for use in an earthen annulus is provided having a dual seal arrangement. The drill bit includes at least one leg having a journal segment, and a roller cone mounted upon the journal segment and forming at least one bearing cavity therebetween. An annular primary seal is disposed between the leg and roller cone and between the bearing cavity and the earthen annulus. An annular secondary seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annulus to the annular primary seal.

Abstract: A drill bit for use in an earthen annulus that contains loose particles is connected to a fluid supply source and includes a bit body having at least one journal segment and at least one fluid conduit in fluid communication with the fluid supply source. A roller cone is rotatably mounted upon the journal segment and forms at least one bearing cavity therebetween. An annular primary seal is disposed between the roller cone and the bit body and between the bearing cavity and the earthen annulus, and an annular gap is disposed between the annular primary seal and the earthen annulus. The annular gap is in fluid communication with the fluid conduit and the earthen annulus. An annular secondary seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annulus to the annular primary seal.

Abstract: A milled teeth rotary cone rock bit consists of chisel crested milled teeth with generously radiused corners at the ends of the crest. A concave depression is formed in the crest between the radiused ends. A layer of hardfacing material formed over each tooth is thicker at the corners and in the concave depressions in the crest to provide a means to inhibit wear of the hardfacing as the bit works in a borehole.

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.