Abstract: An earth-boring bit has a bit body and at least one bearing shaft depending inwardly and downwardly from the bit body. The bearing shaft has a base and a generally cylindrical bearing surface and at least one cutter is mounted for rotation on the bearing shaft. A bearing seal recess is formed generally at the base of the bearing shaft and defines a cylindrical seal face radially recessed from the journal bearing surface. A cutter seal recess is formed in the cutter generally opposite the bearing seal recess and defines a bearing cylindrical seal face. The cutter and bearing seal recesses define a seal gland including a pair of opposed radial seal surfaces. A resilient seal ring is disposed in the seal gland and compressed between the cylindrical seal faces.

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 resilient sealing ring which is formed of a carboxylated hydrogenated acrylonitrile butadiene rubber.

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

Abstract: A solid head earth boring bit has a central tungsten carbide core sealed at the lower end of a drilling fluid passage that extends through the bit to the face of the bit. The core has a nozzle passage extending through it that is offset from the axis of the drilling fluid passage. The core also has at least one cutting element secured to its face. The cutting elements are secured in holes in the core.

Abstract: An earth boring rock bit having a sealed bearing with air or gas as the circulating medium. An annular groove is formed in the vicinity of the seal and connected to the interior of the bit for cooling the seal and cleaning debris from the area of the seal. An air groove scraper is mounted on the shaft in the exit port of the annular groove to prevent the annular groove from becoming plugged by debris mixing with moisture in the hole.

Abstract: Disclosed herein is an earth boring bit of otherwise conventional construction except for the bearing and cutter retention. A snap ring is used to retain the cutter, the grooves that receive the ring and the ring construction being such that the ring is forced into the retainer groove when the cone is thrust inward. The ring cannot therefor accidentally return to its assembly position to permit cutter loss. This enables the use of exclusively frictional bearings and retainer means of exceptional strength and reliability.

Abstract: An earth boring bit has features to reduce stress concentration. The earth boring bit is of the type having three bit legs, each bit leg having a depending bearing pin for rotatably carrying a cutter. An annular fillet is formed at the junction of the bearing pin and the bit leg for receiving a seal ring. To relieve stress above the fillet and on the inside surface of the bit leg, a depression is formed. The depression is formed in the inside surface of the bit leg with a lower edge commencing at the top of the fillet. The depression is curved in vertical cross-section and is located behind the backface of the cutter.

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.