Abstract: An improved rigid face seal that minimizes pressure fluctuations in the lubricant in the vicinity of the seal assembly. The assembly has a first ring with a radial seal face that opposes and engages an opposed radial seal face of a second rigid ring. A first resilient energizer ring is compressed between opposed, generally conical surfaces, one on the first rigid seal ring and the other in a shaft seal groove. The mid-section of the first energizer ring is positioned relative to the journal bearing surface such that its inner periphery is inside the journal bearing surface and thereby defines an essentially constant, lubricant-filled volume between the seal assembly and the shaft seal groove--even as the cutter and seal assembly move relative to the shaft during drilling. A second energizer ring is provided to maintain sealing engagement between the radial seal faces of the first rigid ring and the second rigid ring.

Abstract: An earth boring bit having a body and a cantilevered bearing shaft extending inwardly and downwardly from the body. A rotatable cutter with an open end is assembled over the shaft, which has a radial bearing surface formed around a longitudinal axis. The cutter has a radial bearing surface sized to permit assembly over the journal surface of the shaft. The shaft and cutter have opposed thrust bearing surfaces, one of which has a gradually tapered outer region and a planar inner region to gradually reduce peak stress from a maximum to a minimum and avoid abrupt changes in stress from a high to a low value.

Abstract: An improved mechanical face seal for rock bits using rigid rings and energizers placed in recesses or grooves in the cutter and bearing shaft. The minimum diameter of the shaft groove is substantially equal to the relaxed inside diameter of the shaft energizer and the maximum diameter of the cutter recess is substantially equal to the relaxed outside diameter of the cutter energizer. The radii at the inner end of the shaft groove and the outer end of the cone groove conform to the relaxed cross-section of their respective energizers. The mean diameter of the shaft energizer is substantially equal to the cone journal diameter and the product of the mean diameter and cross-sectional diameter is the same for both energizers.

Abstract: An earth boring bit having an improved two piece bearing and seal assembly containing a cantilevered bearing lug that is threaded to receive a mating bearing sleeve, the lug having a transverse shoulder intersected by a mouth on the sleeve to define a bearing shaft upon which is supported a rotatable cutter. A lubrication system includes a hydrostatic pressure compensator and seal means, the transverse shoulder being positioned inwardly of the seal means toward an inner end region of the lug to avoid exposure of the transverse shoulder of the lug and the mouth of the bearing sleeve to ambient drilling fluid. The seal means is a rigid face seal assembly which includes a rigid, sealing ring and a resilient energizer ring.