Excavation Engineering Associates, Inc.

James E Friant

Levent Ozdemir

Michael A Anderson

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. The pedestal mounts each include, at the lower reaches thereof, at least one small diameter single cutting edge rolling disc cutter. The rolling disc cutters are affixed at individually preselected radially spaced apart locations with respect to a central longitudinal axis forming the center of rotation of the rotary drill bit. Also, each of the rolling disc cutters is mounted at a preselected angle delta with respect to the central longitudinal axis forming the center of rotation of the rotary drill bit. Also, the rolling disc cutters are preferably detachably affixed to the pedestal mounts.

Small disc cutter, and drill bits, cutterheads, and tunnel boring

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. This capacity permits single disc cutter technology to be applied to smaller bits or cutterheads than previously possible. Also, a unique method of shaping and installing hard metal inserts improves cutting efficiency over the life of the cutter, and increases wear life in highly abrasive conditions.

Shielded cutterhead with small rolling disc cutters

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. Also, a unique method of shaping and installing hard metal inserts improves cutting efficiency over the life of the cutter, and increases wear life in highly abrasive conditions.

Disc cutter and excavation equipment

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. This simplified cutter design is achieved by using a comparatively large stiff shaft which is preferably in the range of 40-50% of the cutter ring diameter. The stiff shaft design permits cantilever mount of the cutter on a cutterhead. The design allows increased loading of the disk cutter footprint, and permits single disc cutter technology to be applied to small bits or cutterheads. Also, hard metal cutting edge inserts with reduced leading and trailing edge surface curvature are provided.

Growing community of inventors

Seattle, WA, United States of America

James E Friant