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US 4,706,765 AGranted
Drill bit assembly
AssigneeFour E Inc.
InventorsErnie J. Lee, William L. Thornton
Life of this patent
Estimating the term…
Abstract
A drill bit assembly comprised of a pilot bit and a plurality of add-on reamer sections which are sized to progressively increase the diameter of the hole in measured increments. Both the pilot bit and the reamer sections have two cutter elements which take advantage of the bi-center concept and both use knife edged cutters instead of teeth to drill the hole.
Claims28
A drill bit assembly comprising:
- a pilot bit comprising:
- a bit body having two legs radially positioned 120.degree. apart thereon and depending from the lower surface thereof, said lower surface of said bit body away from said legs being beveled to reduce the effective area of said lower surface;
- a cutter cone rotatably mounted on each of said legs and extending inward and downward whereby the inner tip of each cone lies on the centerline of said body;
- each of said cones having a plurality of smooth circular cutting knife edges spaced along the surface thereof whereby said cutting edges on one of said cones will track between the pathes defined by said cutting edges on the other of said cones when said bit is rotated during drilling operation to thereby cut all of the bottom area of the hole to be drilled;
- a first reamer section comprising:
- a reamer body connected to the upper end of said pilot bit;
- two disk cutters;
- and
- means for rotatable mounting said disk cutters on said body at points radially spaced 120.degree. from each other and positioned to drill a hole having a diameter larger than that of the hole drilled by said pilot bit.
6 more elements
A two-cone drill bit comprising:
- a body having two legs radially positioned 120.degree. apart thereon and depending from the lower surface thereof;
- said lower surface of said bit body away from said legs being beveled to reduce the effective area of said lower surface;
- a journal pin on each leg extending inward and downward toward the centerline of said body;
- two cutter cones;
- means for rotatably mounting said cones on respective said journal pins whereby the inner tips of said cones lie on said centerline of said body;
- and wherein
- each of said cones having a plurality of smooth circular, cutting knife edges spaced along the surface thereof whereby said cutting edges on one of the said cones will track between the pathes defined by said cutting edges on the other of said cones when said bit is rotated during drilling operation to thereby cut all of the bottom area of the hole to be drilled.
4 more elements
A reamer section comprising:
- a reamer body having an externally threaded pin member and an internally threaded box member;
- said reamer body having two recesses therein which are radially spaced 120.degree. apart, said reamer body having a lower surface which is beveled away from disk cutters to reduce the effective area of said lower surface;
- two disk cutters, each disk cutter having a smooth, knife cutting edge having an outer side, and
- means for rotatably mounting one of said disk cutter in each of said recesses.
1 more element
Dependencies are inferred from the claim text.