Patent ID: 6347676
Filing Date: 2002-02-19
Classification: E21B

Abstract:
A tooth type rolling cutter drill bit having a bit body, a plurality of depending legs mounted on the bit body, and a rolling cutter mounted on each depending leg, each rolling cutter having a cutter shell surface, and a plurality of wedge-shaped cutting teeth formed on the cutter shell surface, at least one of the teeth having a top, a plurality of sides, and a base, the sides of the tooth comprising a pair of substantially flat flanks and a pair of curved end surfaces, the substantially flat flanks join at the top of the tooth to form an elongated cutting edge, a buttress is formed about the base of the tooth, the flanks and sides of the tooth blend smoothly into the buttress, wherein the buttress and at least one of the curved end surfaces of the tooth form a convex surface at the base of the tooth and wherein at least one secondary cutting element is formed on at least one of the flanks of the tooth between the elongated cutting edge and the buttress, the secondary cutting element comprising a secondary cutting edge with a protrusion extending from the flank of the tooth and having a top end adjacent to, but not touching, the elongated cutting edge of the tooth and a bottom end that is adjacent to the buttress, wherein the secondary cutting edge is aligned generally perpendicular to the elongated cutting edge of the tooth.