Abstract: A rotary drill bit assembly comprising a drill bit body, at least one trunnion formed integrally with the drill bit body and a rotary cutter rotatably supported on the trunnion by bearing means. The bearing means consist of at least two rows of balls which ride between an inner raceway groove formed integrally in the trunnion and an outer raceway groove formed in the interior peripheral surface of the rotary cutter. A filling hole or port is provided in the drill bit body which terminates at its inner end in each raceway so that the balls of the corresponding row may be assembled in the annular space between the trunnion and rotary cutter. A filler pin closes the corresponding filling hole or port and has a terminal end which complements the cross section of the raceway groove.

Abstract: A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one radial roller bearing on the trunnion. The rolling elements of the bearing are guided on at least one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing race groove is formed on the trunnion for the rolling elements of the radial roller bearing. At least one filling opening is provided which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one pair of filler piece for sealing the opening. One of the filler pieces is made of an elastically compressible material.

Abstract: A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one pair of radial rolling bearings on the trunnion. The rolling elements of at least one bearing are guided on at last one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing groove is formed on the trunnion for the rolling elements of the radial roller bearing. A filling opening is provided for assembly of the rolling elements comprising a channel which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one filler piece for sealing the opening. The filling opening is arranged to provide a common filling means for each radial bearing.

Abstract: A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one radial roller bearing on the trunnion. The rolling elements of the bearing are guided on at least one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing race groove is formed on the trunnion for the rolling elements of the radial roller bearing. At least one filling opening is provided which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one filler piece for sealing the opening.

Abstract: A rotary drill bit assembly comprising a trunnion and at least one rotary cutter mounted on the trunnion. The trunnion is supported by bearings including at least one radial bearing and at least one axial roller bearing. The axial bearing is comprised of conical rollers and one of the races for this bearing is disposed perpendicular to the axis of rotation of the rotary cutter and the complementary bearing race is conical. A guide rim is associated with one of the bearing races which guides the conical rollers in a radially outward direction.

Abstract: A rotary roller bit for drilling earth and rock formations, having a main body and three legs extending outwardly therefrom. Each of the legs carries a conical roller cutter with internal bearings and there is a seal around the periphery of the top of the roller cutter. The periphery of the roller cutter is spaced from the adjacent portion of the leg so as to provide a jet slot for the discharge of air. Adjacent the slot and radially inwardly is an air chamber which is formed between an annular surface of the leg and a seal ring. The air chamber is substantially greater in its dimension axially of the roller cutter and air is supplied to it under sufficient pressure to cause a jet of air to flow from the jet slot at a sufficient rate to prevent the entry of rock particles and dirt into the roller cutter.