Abstract: A cutting cone on a rotary rock bit is captively retained on a journal pin by an annular array of ball bearings disposed in laterally facing annular races formed in the cone and pin. When a predetermined amount of surface wear has occurred between the cone and pin as the bit is operated, one or more of the balls is caused to axially shift into and become trapped in a small lockup grooved formed in the journal pin and communicating with its race. Other balls become wedged between the trapped balls and the cone, thereby rotationally locking the cone on its pin and preventing further pin-cone surface wear which might otherwise cause cone loss. During operation of the bit, the locked cone produces a readily detectable increase in rotary table torque, and a decrease in bit penetration rate, thereby signalling the driller that the bit needs replacement.

Abstract: An improved radial rock bit seal for utilization with earth boring drill bits which employ rolling cutters mounted on shafts extending from face surfaces on the drill bit body. The improved seal includes a cylindrical body which is disposed around each shaft and which has two axially displaced seal portions. The first seal portion includes an elastomeric sealing surface which is disposed in sealing and sliding engagement with the shaft. The second seal portion includes an elastomeric sealing surface which is disposed in sealing and sliding engagement with the rolling cutter. A flexible juncture between each of the two seal portions permits the seal portions to move somewhat independently in response to loading of the rolling cutter and this permits both seals to maintain substantially the same seal compression in spite of such loading.

Abstract: An improved seal for utilization with earth boring drill bits which employ rolling cutters mounted on shafts extending from face surfaces on the drill bit body. The improved seal includes a generally cylindrical elastomeric seal which is disposed around each shaft with one end of the generally cylindrical elastomeric seal in sealing and sliding engagement with the face surface surrounding that shaft. The second end of the generally cylindrical elastomeric seal is engaged in sealing and sliding engagement with a surface on the rolling cutter. A rigid generally cylindrical ring is disposed within each generally cylindrical elastomeric seal preferably near the outer surface thereof and serves to minimize radial distortion of the generally cylindrical elastomeric seal in response to axial compression.

Abstract: An improved seal assembly for utilization with earth boring drilling bits employing roller cutters. The improved seal is constructed utilizing two resilient O-rings or other resilient seals engaging opposing surfaces in the roller cutter and the corner formed by the shaft and face of the cutter support. The O-rings are mounted in and separated by a flexible floating ring of slightly harder material than the O-ring material. The flexible floating ring may be coated with or made from a material which provides a low coefficient of friction, permitting the O-rings to rotate therein. In an alternate embodiment of the present invention the flexible floating ring is tapered so that increased loading of the earth boring drilling bit will result in increased compression of the resilient O-rings, thus improving the seal under high load conditions.