Modular hybrid drill bit

Abstract

An earth-boring bit comprising a bit body is cofigured at its upper end for connection into a drillstring. A fixed blade depends axially downwardly from the bit body. An axially extending slot is formed in the bit body adjacent the fixed blade. A bit leg is received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, wherein the bit leg cannot be removed from the slot except by axial movement relative to the bit body. A rolling cutter is secured to the bit leg at its lower extent. A fastener secures the bit leg against movement relative to the bit body and extends through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade. The slot defines a pair of generally opposed sides connected by a third side, the generally opposed sides being inclined toward one another to define a dovetail that corresponds with the shape of the bit leg. The bit body further comprises a shank that is configured for connection into the drillstring at its upper extent and has a generally cylindrical receptacle formed in its lower extent; and a bit body portion having a generally cylindrical upper extent, the receptacle being and dimensioned to receive the upper extent of the bit body, wherein the shank and bit body portions are secured together by welding.

1 . An earth-boring bit comprising:
 a bit body configured at its upper end for connection into a drillstring;   at least one fixed blade depending axially downwardly from the bit body;   an axially extending slot formed in the bit body adjacent the fixed blade;   a bit leg received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, wherein the bit leg cannot be removed from the slot except by axial movement relative to the bit body; and   at least one rolling cutter secured to the bit leg at its lower extent.   
     
     
         2 . The earth-boring bit according to  claim 1 , further comprising:
 at least one fastener securing the bit leg against movement relative to the bit body.   
     
     
         3 . The earth-boring bit according to  claim 2 , wherein the fasteners extend through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade. 
     
     
         4 . The earth-boring bit according to  claim 1 , wherein the slot is formed by at least three sides, and at least one acute angle is formed by two adjacent sides. 
     
     
         5 . The earth-boring bit according to  claim 1 , wherein the slot defines a pair of generally opposed sides connected by a third side, the generally opposed sides being inclined toward one another to define a dovetail that corresponds with the shape of the bit leg. 
     
     
         6 . The earth-boring bit according to  claim 1 , wherein the bit body further comprises:
 a bit body portion having an upper extent; and   a shank that is configured for connection into the drillstring at its upper extent and configured for connection to the bit body at its lower extent, wherein the shank and bit body portions are secured together by welding.   
     
     
         7 . The earth-boring bit according to  claim 1 , further comprising:
 a nozzle removably secured in the bit body, the nozzle receptacle configured to receive a nozzle;   a bearing formed integrally with the bit leg, the rolling cutter mounted for rotation on the bearing; and   a lubricant compensator removably secured in the bit leg, the lubricant compensator in fluid communication with the bearing.   
     
     
         8 . An earth-boring bit comprising:
 a shank configured at its upper extent for connection into a drillstring and having a lower extent;   a body portion configured to connect to the lower extent of the shank, the shank and body portions being removably secured together to form a bit body;   at least one fixed blade depending axially downwardly from the bit body;   an axially extending slot formed in the bit body adjacent the fixed blade;   a bit leg received and retained in the slot by engagement between the slot and correspondingly shaped bit leg;   at least one rolling cutter secured to the bit leg at its lower extent; and   at least one fastener securing the bit leg against movement relative to the bit body.   
     
     
         9 . The earth-boring bit according to  claim 8 , wherein the fasteners extend through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade. 
     
     
         10 . The earth-boring bit according to  claim 8 , wherein the slot is formed by at least three sides and at least one acute angle is formed by two adjacent sides. 
     
     
         11 . The earth-boring bit according to  claim 8 , wherein the slot defines a pair of generally opposed sides connected by a third side, the generally opposed sides being inclined toward one another to define a dovetail that corresponds with the shape of the bit leg. 
     
     
         12 . The earth-boring bit according to  claim 8 , wherein:
 the upper extent of the bit body and the receptacle in the shank portion are generally cylindrical and the receptacle is dimensioned to receive the upper extent of the bit body, wherein the shank and bit body portions are secured together by welding.   
     
     
         13 . The earth-boring bit according to  claim 8 , further comprising:
 a nozzle removably secured in the bit body, the nozzle receptacle configured to receive a nozzle;   a bearing formed integrally with the bit leg, the rolling cutter mounted for rotation on the bearing; and   a lubricant compensator removably secured in the bit leg, the lubricant compensator in fluid communication with the bearing.   
     
     
         14 . The earth-boring bit according to  claim 8 , wherein the fasteners are bolts and the pin and body portions are secured together by welding. 
     
     
         15 . An earth-boring bit comprising:
 a shank configured at its upper extent for connection into a drillstring and having a receptacle formed in its lower extent;   a body portion having an upper extent shaped and dimensioned to be received in the receptacle in the lower extent of the shank, the shank and body portions being removably secured together;   at least one fixed blade depending axially downwardly from the body portion;   an axially extending slot formed in the body portion adjacent the fixed blade;   a bit leg received and retained in the slot by engagement between the slot and correspondingly shaped bit leg, the bit leg having a removable lubricant compensator assembly in fluid communication with a bearing at a lower extent of the bit leg;   at least one rolling cutter mounted for rotation on the bearing of the bit leg; and   at least one fastener securing the bit leg against axial movement relative to the bit body.   
     
     
         16 . The earth-boring bit according to  claim 15 , wherein the fasteners extend through oblong apertures in the bit leg and into the bit body, wherein the bit leg can be moved axially relative to the bit body to adjust the projection of the rolling cutter relative to the fixed blade. 
     
     
         17 . The earth-boring bit according to  claim 15 , wherein the slot is formed by at least three sides and at least one acute angle is formed by two adjacent sides. 
     
     
         18 . The earth-boring bit according to  claim 15 , wherein the slot defines a pair of generally opposed sides connected by a third side, the generally opposed sides being inclined toward one another to define a dovetail that corresponds with the shape of the bit leg. 
     
     
         19 . The earth-boring bit according to  claim 15 , wherein the fasteners are bolts and the pin and body portions are secured together by welding. 
     
     
         20 . The earth-boring bit according to  claim 15 , wherein the receptacle in the shank and the upper extent of the body portion are generally cylindrical.