Wear compensating rock bit insert

A dual component sintered rock bit insert for attachment in a rolling rock bit cutter comprising:

• a body formed of a first component joined along a mating plane to a second component and said mating plane substantially dividing said insert into two equal halves, said first component having a resistance to wear less than said second component, and
• means on said body permitting the mounting of said body on the rock bit cutter such that the mating plane is oriented to position said first component as the leading edge of the insert as said cutter is rotated to effect cutting.

A composite sintered rock bit insert comprising:

• a body having a substantially cylindrical base on one end and a tip portion extending from said base converging inwardly therefrom and terminating in a generally convex earth engaging surface, said tip portion comprises of a first material joined along a mating plane to a second material, said first material having a resistance to wear less than that of said second material, and said mating plane engaging said generally convex surface and extending therefrom toward said cylindrical base in a configuration providing that the outer surfaces of both said first and second materials diverge away from said mating surface to provide in said tip portion progressive increasing distances of said outer surfaces from said mating surface in the direction of said cylindrical base.

A composite sintered rock bit insert for attachment in a rolling rock bit cutter comprising:

• a body having a substantially cylindrical base on one end and a tip on the opposite end, said tip extending from said base converging inwardly therefrom and terminating in a generally convex earth engaging surface, said tip comprised of a first component joined along a mating plane to a second component, said mating plane being substantially perpendicular to the direction of movement of said insert as said cutter is moved to effect cutting.

A dual component sintered rock bit insert comprising:

• a first component defining a first surface of said insert;
• and
• a second component joined along a mating surface to said first component and defining a second surface of said insert, said second component having a resistance to wear greater than that of said first component, said mating surface substantially dividing said insert into equal halves.

A rock bit cutter comprising:

• a rotatable drill bit having a plurality of sintered composite inserts mounted in the working face thereof, said inserts having a body with a first portion comprised of a first material joined along a mating surface to a second portion comprised of a second material, said first material having a resistance to wear less than said second material and said mating surface extending to an earth engaging surface of the insert, said first portion of the insert being oriented to be the leading edge of the insert as said cutter is moved to effect cutting.

In a rotary earth drilling bit, the combination comprising:

• a rolling cutter member mounted in said drill bit for rotation about a rotational axis of said cutter member and having an external working face;
• a plurality of composite sintered bit inserts spaced radially around the working face of said rolling cutter member at a plurality of radial locations spaced longitudinally along said rotational axis, said inserts having a first portion comprised of a first material and joined to a second portion comprised of a second material said first material having a lower wear resistance then that of said second material and said first portion being oriented to be the leading edge of said bit inserts as said rolling cutter member is rotated in a drilling operation.