Patent ID: 8607899

Claim:
A rolling cone drill bit for cutting a borehole having a borehole sidewall, corner and bottom, the drill bit comprising: a bit body including a bit axis; a rolling cone cutter mounted on the bit body and adapted for rotation about a cone axis; a tooth extending from the cone cutter; wherein the tooth includes: a base at the cone cutter and an elongate chisel crest distal the cone cutter, wherein the crest extends along a crest median line between a first crest end and a second crest end and includes an elongate crest apex; a first flanking surface extending from the base to the crest; a second flanking surface extending from the base to the crest; wherein the first flanking surface and the second flanking surface taper towards one another to form the chisel crest; a first raised rib extending continuously along the first flanking surfaces and across the chisel crest to the second flanking surface; wherein the crest extends to a height H c measured perpendicularly from the crest apex to the cone cutter in side view; wherein the first rib extends from the crest apex to a peak distal the crest; wherein the peak of the rib is disposed a first rib height H r1 measured perpendicularly from the crest apex in side view; wherein the first rib has a first rib width W r1 measured perpendicular to a first rib median line; wherein the ratio of the first rib height H r1 to the first rib width Wr1 at the crest apex is between 0.25 and 0.60.