Earth-boring tools carrying formation-engaging structures

Abstract

An earth-boring tool includes a blade located on a body of the earth-boring tool with a pocket formed in an exposed outer surface of the blade. A formation-engaging structure is affixed within the pocket. The formation-engaging structure includes a distal end, a proximal end and a tapered sidewall therebetween. The distal end of the formation-engaging structure includes a formation-engaging surface. The tapered sidewall engages a tapered inner surface of the pocket. The tapered sidewall of the formation-engaging structure and the tapered inner surface of the pocket are each sized and configured to provide an interference fit between the formation-engaging structure and the pocket of the blade. In additional embodiments, instead of retention by interference fit, the formation-engaging structure is retained to the blade by a threaded fastener threaded within a tapped bore extending through the blade. The threaded fastener is received within a receiving formation of the formation-engaging structure.

1 . An earth-boring tool, comprising:
 a body;   at least one blade located on the body of the earth-boring tool;   a pocket opening onto an exposed outer surface of the at least one blade; and   a formation-engaging assembly received within the pocket, the formation-engaging assembly comprising:
 a holder having a distal end, a proximal end, and a tapered sidewall therebetween, the tapered sidewall configured to engage a tapered inner surface of the pocket, the tapered sidewall of the holder and the tapered inner surface of the pocket each sized and configured to provide an interference fit between the holder and the pocket of the at least one blade; and 
 a formation-engaging structure located within the holder, wherein a formation-engaging surface of the formation-engaging structure extends beyond the distal end of the holder. 
   
     
     
         2 . The earth-boring tool of  claim 1 , further comprising a bore extending through the at least one blade from at least one of a rotationally leading surface and a rotationally trailing surface of the at least one blade, the proximal end of the holder extending within the bore, the bore configured to receive a tapered punch, a drift pin, or a fluid pressure transferring medium for dislodging the formation-engaging assembly from the pocket of the at least one blade. 
     
     
         3 . The earth-boring tool of  claim 1 , wherein the formation-engaging structure is secured within a receptacle of the holder by a braze material. 
     
     
         4 . The earth-boring tool of  claim 1 , wherein the interference fit is a result of hydraulic pressing of the holder into the pocket. 
     
     
         5 . The earth-boring tool of  claim 1 , wherein the formation-engaging structure is an insert. 
     
     
         6 . The earth-boring tool of  claim 1 , wherein the interference fit is a result of shrink-fitting the holder into the pocket. 
     
     
         7 . The earth-boring tool of  claim 1 , wherein the formation-engaging structure comprises a volume of superabrasive material over a substrate, the formation-engaging surface comprising a surface of the volume of superabrasive material. 
     
     
         8 . An earth-boring tool, comprising:
 a body;   at least one blade located on the body of the earth-boring tool;   a pocket opening onto an exposed outer surface of the at least one blade; and   a formation-engaging structure received within the pocket, the formation-engaging structure having a distal end, a proximal end, and a tapered sidewall therebetween, the distal end of the formation-engaging structure having a formation-engaging surface, the tapered sidewall configured to engage a tapered inner surface of the pocket, wherein the tapered sidewall of the formation-engaging structure and the tapered inner surface of the pocket are each sized and configured to provide an interference fit between the formation-engaging structure and the pocket of the at least one blade.   
     
     
         9 . The earth-boring tool of  claim 8 , further comprising a bore extending through the at least one blade from at least one of a rotationally leading surface and a rotationally trailing surface of the at least one blade, the proximal end of the formation-engaging structure extending within the bore, the bore configured to receive a tapered punch, a drift pin, or a fluid pressure transferring medium for dislodging the formation-engaging structure from the pocket of the at least one blade. 
     
     
         10 . The earth-boring tool of  claim 8 , wherein the interference fit of the formation-engaging structure within the pocket is a result of one or more of hydraulically pressing and shrink fitting the formation-engaging structure within the pocket. 
     
     
         11 . The earth-boring tool of  claim 8 , wherein the formation-engaging structure comprises a volume of superabrasive material over a substrate, the formation-engaging surface comprising a surface of the volume of superabrasive material, the formation-engaging structure being an insert. 
     
     
         12 . The earth-boring tool of  claim 11 , wherein the insert is a non-cutting bearing element positioned and oriented on the body as a rubbing surface configured to rub against a formation as the body of the earth-boring tool is rotated within a wellbore, a distal end of the insert having an ovoid-shaped surface. 
     
     
         13 . The earth-boring tool of  claim 8 , further comprising cutting elements positioned in respective cutting element pockets on the exposed outer surface of the at least one blade, wherein the cutting elements comprise a polycrystalline diamond compact. 
     
     
         14 . The earth-boring tool of  claim 13 , wherein the cutting elements are located on a rotationally leading surface of the at least one blade and the formation-engaging structure is located rotationally behind the cutting elements on the same blade. 
     
     
         15 . The earth-boring tool of  claim 13 , wherein the formation-engaging structure is positioned intermediate at least two cutting elements along a radial axis of the body of the earth-boring tool. 
     
     
         16 . The earth-boring tool of  claim 1 , wherein the holder is embedded within the at least one blade with the tapered sidewall of the holder being at least substantially surrounded by material of the at least one blade. 
     
     
         17 . The earth-boring tool of  claim 1 , wherein the formation-engaging structure comprises a generally cylindrical sidewall corresponding to a generally cylindrical inner sidewall of the holder. 
     
     
         18 . The earth-boring tool of  claim 1 , wherein a maximum lateral extent of the formation-engaging structure is less than an outer perimeter of a receptacle of the holder. 
     
     
         19 . The earth-boring tool of  claim 1 , wherein the distal end of the holder is substantially flush with the exposed outer surface of the at least one blade. 
     
     
         20 . The earth-boring tool of  claim 2 , wherein the rotationally leading surface is a leading surface of the blade as the at least one blade rotates around an axis of rotation of the body of the earth-boring tool, the rotationally trailing surface being a trailing surface of the blade as the at least one blade rotates around the axis of rotation of the body of the earth-boring tool, the bore comprising a through bore extending from the rotationally leading surface to the rotationally trailing surface of the at least one blade.