Drill Bit

Abstract

A drill bit features a head portion and a connecting portion for attachment to a drilling device. The head portion includes at least two insert pockets, which can contain inserts, with cutting edges that extend from an inner position offset radially from the rotational axis of the bit to an outer cutting edge. The cutting edge is formed by the intersection of a top surface and a wear surface of the insert pocket or insert. The top surface is linear, but may be planar or non-planar.

What is claimed is: 
     
         1 . A drill bit comprising a head portion and a connecting portion for attachment to a drilling device, the head portion comprises at least two insert pockets each including an insert with cutting edges that extend from an inner position offset radially from the rotational axis of the bit to a linear outer cutting edge, wherein the inserts are skewed in relation to radii of the drill bit. 
     
     
         2 . The drill bit according to  claim 1 , wherein the inserts are raked back with a rake angle of about 10° to about 30°. 
     
     
         3 . The drill bit according to  claim 1 , wherein the inserts are skewed with a skew angle of about −20° to about +20°. 
     
     
         4 . The drill bit according to  claim 3 , wherein the inserts are skewed with a positive skew angle. 
     
     
         5 . The drill bit according to  claim 1 , wherein the inserts are skewed with a skew angle of about 1° to about 20°. 
     
     
         6 . The drill bit according to  claim 1 , wherein the inserts are leaned with a lean angle of about 10° to about 30°. 
     
     
         7 . The drill bit according to  claim 1 , wherein the inserts are leaned with a lean angle of about 10° to about 30° and are skewed with a skew angle of about 1° to about 20°. 
     
     
         8 . The drill bit according to  claim 1 , wherein the inserts are skewed with a skew angle of about 1° to about 20° and raked back with a rake angle of about 10° to about 30°. 
     
     
         9 . The drill bit according to  claim 1 , wherein the inserts are formed of a substrate that is at least partially covered by a superhard material. 
     
     
         10 . The drill bit according to  claim 9 , wherein the substrate is comprised of cemented carbide. 
     
     
         11 . The drill bit according to  claim 9 , wherein the superhard material is selected from the group consisting of diamond and cubic boron nitride. 
     
     
         12 . The drill bit according to  claim 1 , wherein the top surface of the inserts have a non-planar surface. 
     
     
         13 . The drill bit according to  claim 12 , wherein the non-planar surface includes a wavy surface extending along a linear path. 
     
     
         14 . The drill bit according to  claim 13 , wherein crests of the wavy surface of one insert are radially offset from the crests of the wavy surfaces of other inserts. 
     
     
         15 . The drill bit according to  claim 13 , wherein the wavy surface of one insert is 180° out of phase with another insert. 
     
     
         16 . A drill bit comprising a head portion and a connecting portion for attachment to a drilling device, the head portion comprises at least two insert pockets each including an insert with cutting edges that extend from an inner position offset radially from the rotational axis of the bit to a linear outer cutting edge, wherein the inserts are skewed in relation to radii of the drill bit, and wherein the inserts have a top surface that is non-planar extending along a linear path. 
     
     
         17 . The drill bit according to  claim 16 , wherein the top surface includes a wavy surface that extends along a linear path. 
     
     
         18 . The drill bit according to  claim 16 , wherein crests of the waves on the top surfaces of the inserts are radially offset from the waves on the top surface of any other insert in the drill bit. 
     
     
         19 . A drill bit comprising a head portion and a connecting portion for attachment to a drilling device, the head portion comprises at least two insert pockets each including an insert with cutting edges that extend from an inner position offset radially from the rotational axis of the bit to a linear outer cutting edge, wherein the inserts are raked back with a rake angle of about 10° to about 30°, skewed with a skew angle of about 1° to about 20°, and leaned with a lean angle of about 10° to about 30°. 
     
     
         20 . The drill bit according to  claim 19 , wherein a distance between the cutting edges of the inserts formed by being offset radially from the rotational axis of the bit is from about 25% to about 75% of a total diameter of the drill bit.