Abstract: An earth boring (rock) bit having a flexible diaphragm located inside the bearing shaft in a cavity between a threaded lug and a mating bearing sleeve. The diaphragm has an enlarged periphery, shaped somewhat like an o-ring, that is confined and sealed between opposed annular surfaces on the lug and the sleeve. The circular periphery of the diaphragm and cavity provide good compensation volume, from which excessive lubricant pressure is relieved by an enlarged portion which is punctured and contoured to discharge lubricant under excessive pressure while excluding drilling fluid. Simplicity and reliability are achieved by the elimination of multiple and complex manufacture and assembly operations.

Abstract: An earth boring bit with sealed and lubricated bearings and rotatable cutters, the seals being isolated from detritus in the borehole by a seal protector ring and groove. The ring, generally L shaped in cross-section, has radial and axial clearances from the registering groove to maintain a labyrinth path with selected values, irrespective of cone movement during drilling.

Abstract: An earth boring bit having an improved two piece bearing construction using an internally tapered and threaded, cantilevered bearing lug extending obliquely inwardly and downwardly from a leg carried by the body of the bit. An internally tapered and threaded bearing sleeve is made up on the lug, and includes a mouth that engages a shoulder on a base region of the bearing lug. The mouth of the sleeve has a minimum radial thickness such that the sleeve may be made up to a selected minimum torque. The bearing sleeve has a length greater than that of the treaded portion to define a thick walled inner end region to receive a resilient retainer ring in a groove that provides a minimum section over the threads on the interior of the sleeve. The sleeve is boronized to achieve wear resistance in a manner that does not substantially reduce strength.