Abstract: Small diameter rotary drill bits using rolling disc cutters. Novel small diameter rotary drill bits with detachable pedestal mounted rolling disc cutters are provided. The bit body has a plurality of longitudinal edge mounting slots located at preselected angularly spaced apart locations. Preferably, the slots each have an upper protective ledge and downwardly extending sidewalls. A set of peripheral pedestal mounts each having a mounting portion sized and shaped to fit into a preselected mounting slot are provided and each is detachably mounted in its preselected mounting slot. In one embodiment, the longitudinally extending slots further comprise a wedge shaped edge portion, and the pedestal mounts have a complimentary angularly shaped portion, so that when the pedestal mount is brought into a close fitting relationship with the longitudinal slot, the pedestal mount and the longitudinal slot are tightly and securely interfitting.

Abstract: An improved disc type rolling rock cutter, and novel cutterheads employing such cutters. A rock cutter with an improved, simplified structure, with compact bearing, and smooth, rounded blade shape is disclosed. The design incorporates a cutter ring, bearing, and seal into a single cutter ring assembly. The cutter may be assembled and disassembled for rework by a single worker with simple hand tools. Replacement of worn out cutter rings is done quickly and easily by removing the old ring assembly and then sliding a new ring, bearing, and seal assembly on to the cutter shaft. This simplified assembly is achieved by using a comparatively large shaft which is normally in the range of 40-50% of the ring diameter. The shaft design is sufficiently robust to permit a cantilever mount of the cutter. The unique configuration allows 30,000 lbs. or more thrust to be applied to a 5 inch diameter miniature disc.

Abstract: An improved disc type rolling rock cutter, and novel cutterheads employing such cutters. A rock cutter with an improved, simplified structure, with compact bearing, and smooth, rounded blade shape is disclosed. The design incorporates a cutter ring, bearing assembly, and seal assembly. The cutter may be assembled and disassembled for rework by a single worker with simple hand tools. Replacement of worn out cutter rings is done quickly and easily by removing the old ring assembly and then sliding a new ring, bearing, and seal assembly on to the cutter shaft. This simplified assembly is achieved by using a comparatively large shaft which is normally in the range of 30-50% of the ring diameter. The shaft design is sufficiently robust to permit a cantilever mount of the cutter. The unique configuration allows 30,000 lbs. or more thrust to be applied to a 5 inch diameter miniature disc. This capacity permits single disc cutter technology to be applied to smaller bits or cutterheads than previously possible.

Abstract: An improved rolling disc type cutter, and novel cutterheads employing such cutters. The cutter includes a washer surface and a cutter ring assembly. The cutter ring assembly further includes an annular cutter ring with an interior annulus defining portion and an outer ring portion. A bearing assembly substantially fits into the annulus of the cutter ring in a close fitting relationship with the shaft, so that the cutter ring may rotate with respect to and be supported by said shaft. The bearing assembly includes a bearing and a seal which fits between the washer surface and the cutter ring to form a lubricant retaining seal for the interior annulus portion of the cutter ring. A retainer assembly is used to retain the cutter ring assembly on the shaft, and a cap seals the interior annular portion of the cutter ring assembly so that, in cooperation with the seal and the cutter ring, a lubricant retaining chamber is provided.