Earth boring cutter employing helical teeth

Abstract

An earth bit includes an earth bit body and a lug and cutting cone carried by the earth bit body, wherein the cutting cone is rotatably mounted to the lug. A plurality of cutters are carried by the earth bit body, wherein the cutters include a cutter body and a plurality of curved teeth extending between opposed ends of the cutter body. The curved teeth are positioned so that one end of a tooth overlaps an opposed end of an adjacent tooth. The curved teeth of a first cutter extend in a direction around its corresponding cutter body and the curved teeth of a second cutter extend in an opposed direction around its corresponding cutter body.

1 . A cutter, comprising:
 a cutter body having opposed openings; and   a plurality of curved teeth extending around the outer periphery of the cutter body and between opposed ends, wherein the curved teeth have a curved edge, and a curved leading face that curves as it extends between opposed ends of the cutter body.   
   
   
       2 . The cutter of  claim 1 , wherein the curved teeth are positioned so that an end of a curved tooth overlaps an opposed end of an adjacent curved tooth. 
   
   
       3 . The cutter of  claim 1 , wherein opposed ends of each curved tooth have different dimensions. 
   
   
       4 . The cutter of  claim 1 , wherein the plurality of curved teeth includes at least one curved tooth having first and second tooth portions spaced apart from each other. 
   
   
       5 . The cutter of  claim 1 , wherein the plurality of curved teeth includes first and second notched curved teeth. 
   
   
       6 . The cutter of  claim 5 , wherein the notches of the first and second notched curved teeth are offset from each other. 
   
   
       7 . The cutter of  claim 5 , wherein the plurality of curved teeth includes an unnotched curved tooth. 
   
   
       8 . An earth bit, comprising:
 an earth bit body; and   a first cutter rotatably mounted to the earth bit body with a first saddle, the first cutter including a cutter body and a first plurality of curved teeth extending in a direction around the outer periphery of the cutter body and between opposed ends, the curved teeth being positioned so that one end of a curved tooth overlaps an opposed end of an adjacent curved tooth.   
   
   
       9 . The cutter of  claim 8 , wherein the dimensions of a curved tooth at its end surface are smaller than the dimensions of the curved tooth at its opposed end surface. 
   
   
       10 . The cutter of  claim 8 , wherein the curved teeth include a curved edge, and a curved face that curves as it extends away from the curved edge. 
   
   
       11 . The cutter of  claim 8 , wherein the first plurality of curved teeth includes at least one curved tooth having first and second tooth portions spaced apart from each other. 
   
   
       12 . The earth bit of  claim 8 , further including a second cutter rotatably mounted to the earth bit body with a second saddle, the second cutter including
 a cutter body; and   a second plurality of curved teeth extending between opposed ends and in an opposed direction around the outer periphery of the cutter body, the curved teeth being positioned so that one end of a curved tooth overlaps the opposed end of an adjacent curved tooth.   
   
   
       13 . The earth bit of  claim 12 , wherein the number of curved teeth of the first and second cutters are the same. 
   
   
       14 . The earth bit of  claim 12 , wherein the first and second saddles are offset from each other. 
   
   
       15 . The earth bit of  claim 12 , further including a third cutter rotatably mounted to the earth bit body with a third saddle, the third cutter including
 a cutter body; and   a third plurality of curved teeth extending between opposed ends and in the direction around the outer periphery of the cutter body, the curved teeth being positioned so that one end of a curved tooth overlaps the opposed end of an adjacent curved tooth;   wherein the second cutter is positioned between the first and third cutters.   
   
   
       16 . An earth bit, comprising:
 an earth bit body;   a lug and cutting cone carried by the earth bit body, the cutting cone being rotatably mounted to the lug; and   a plurality of cutters carried by the earth bit body, wherein the cutters include a cutter body and a plurality of curved teeth extending between opposed ends of the cutter body, the curved teeth being positioned so that one end of a tooth overlaps an opposed end of an adjacent tooth;   wherein the curved teeth of a first cutter extend in a direction around its corresponding cutter body and the curved teeth of a second cutter extend in an opposed direction around its corresponding cutter body.   
   
   
       17 . The earth bit of  claim 16 , wherein a tooth of the first cutter includes first and second tooth portions spaced apart from each other. 
   
   
       18 . The cutter of  claim 16 , wherein the dimensions of a curved tooth of the first cutter at its opposed end surfaces are different from each other. 
   
   
       19 . The cutter of  claim 16 , further including a third cutter having teeth which extend in the same direction as the teeth of the first cutter, the second cutter being positioned between the first and third cutters. 
   
   
       20 . The cutter of  claim 19 , wherein the second cutter is offset from the first and third cutters.