PDC cutter and bit
AssigneeNL Industries, Inc.
InventorLot W. Short, Jr.
Life of this patent
Estimating the term…
Abstract
The invention comprises a drag-type drill bit and a cutting member therefor. Each of the cutting members comprises a stud having a shank adjacent one end mounted in a respective bore in the bit body and a head adjacent the opposite end projecting outwardly from the bit body. The head has a lip formation adjacent the juncture of the head and shank. The lip extends laterally outwardly with respect to the shank to overly the outer surface of the bit body adjacent the respective bore. The cutting face is concave, presenting a plurality of different back rake angles, which angles increase with distance from the lip formation.
Claims28
A cutting member for mounting on a drill bit comprising:
- an elongate body comprised of sintered tungsten carbide, said elongate body having a mounting portion adjacent one end, said mounting portion being adapted to be received in a bore in a drill bit body, and an operating portion adjacent the opposite end, said operating portion being adapted to project outwardly from said drill bit body when said mounting portion is so received in such bore, and said operating portion having a lip formation adjacent the juncture of said mounting and operating portions, said lip formation extending laterally outwardly with respect to said mounting portion whereby it may overly the outer surface of such bit body adjacent such bore when said mounting portion is so received therein, and said lip formation defining a shoulder facing axially toward said one end of said elongate body, and wherein said operating portion is flared radially outwardly to the outer edge of said shoulder.
A self-sharpening cutting member for mounting on a drag-type drill bit comprising:
- an elongate body and a layer of superhard material carried on said body and defining a cutting face adjacent one end of said body, said cutting face having an original cutting edge disposed axially outermost and having a plurality of back rake angles becoming more negative from said original cutting edge axially inwardly, a tangent to said cutting face at said original cutting edge lying in a plane passing longitudinally through said elongate body.
A cutting member for mounting on a drill bit comprising:
- an elongate body comprised of sintered tungsten carbide, said elongate body having a stud-like mounting portion adjacent one end and an operating portion adjacent the opposite end, said body having a shoulder adjacent the juncture of said mounting and operating portions and facing axially toward said one end, and said operating portion flaring radially outwardly to the outer edge of said shoulder.
A drag-type drill bit comprising:
- a bit body;
- a plurality of cutting members mounted on said bit body, each of said cutting members comprising an elongate body comprised of sintered tungsten carbide, said elongate body having a mounting portion adjacent one end brazed into a respective bore in said bit body, and an operating portion adjacent the opposite end projecting outwardly from said bit body, said operating portion having a lip formation adjacent the juncture of said mounting and operating portions, said lip formation extending laterally outwardly with respect to said mounting portion and overlying the outer surface of said bit body adjacent the respective bore and thereby shielding the brazed interface between said mounting body of said bit body, said lip formation forming an obtuse angle with the surface of said bit body outwardly of said lip formation.
Dependencies are inferred from the claim text.