Abstract: Discloses a rotary bit bearing system for each cutter cone of a bit including ball bearings rotatably supporting the cone around a leg journal, a lateral sleeve bearing rotatably supporting the cone including a freely rotatably cylindrical composite sleeve bearing mounted between an inner bearing face and an outer bearing face. The composite sleeve comprises a first cylindrical sleeve member, a second cylindrical sleeve member, and a spacer disc thrust member mounted in freely rotatable relation between the first and second sleeve members. Also includes a disc thrust bearing rotatably supporting the cone to withstand axial forces including an external disc bearing, an internal disc bearing, and an intermediate disc bearing mounted in freely rotatable relationship between the external and the internal disc bearing with the intermediate disc bearing means including radial guide means to radially guide the internal and the external disc bearing.

Abstract: A lubrication failure detection system for utilization with an earth boring drilling system having at least one rotary drill bit coupled to a drill string, the drill string having an internal passage adapted to receive drilling fluid under pressure. A lubrication reservoir is disposed near said rotary drill bit and coupled to bearing surfaces within said rotary drill bit by a lubrication passageway. A flexible membrane separates the lubrication reservoir from drilling fluid within the annulus formed by the rotary drill bit and distends inward in response to the pressure of the drilling fluid. The distention of the membrane forces lubricant into the lubrication passageway and when the membrane has distended to a selected point, the membrane actuates a mechanism which opens an orifice into the internal passage of the drill string, thereby abruptly decreasing the pressure of the drilling fluid within the drill string.

Abstract: Discloses a lubricant circulating system for a rotary drilling bit including a lubricating space defined between a rotary cone cutter and a journal shaft extending from the bit body, the body defining a lubricant supply passageway connecting the lubricating space with a substantially cylindrical inlet chamber of a lubricant reservoir and with the centerline of the supply passageway being disposed substantially tangential with the cylindrical wall of said inlet chamber to form a restrictive vortex flow passage from the supply passageway into said reservoir and a nonrestrictive return flow passage, the body defining a lubricant exhaust passageway connecting the lubricating space through a substantially cylindrical outlet chamber into a discharge passageway forming part of the reservoir and with the centerline of the discharge passageway being disposed substantially tangential with the cylindrical wall of the outlet chamber to form a restrictive vortex flow passage from the reservoir into the outlet chamber and