Earth boring bit having air tube with removable cap

Abstract

A drill bit has a plurality of air tubes extending into the bowl for separating entrained debris and liquids from air flow used to clean and cool bearings in the cutters of the bit. The air tube is assembled from a tube and a cap. The tube has open ends and a plurality of openings through the sidewall of the tube for allowing air to flow through the openings while preventing large debris from entering the tube. The lower end of the tube is inserted into an inner portion of a fluid passage, and the cap is secured to the upper end of the tube. The cap is removable for providing access to the interior of the tube when necessary to dislodge debris from within the tube.

We claim:  
     
         1 . A drill bit, comprising: 
 a body having at least one leg extending from the body, the body enclosing a bowl;    a passage extending through the body and the leg, the passage being in fluid communication with the bowl;    at least one tube extending from the passage and into the bowl, the tube having open upper and lower ends and being generally cylindrical, the tube having at least one opening along a sidewall of the tube, the lower end of the tube being inserted into the passage; and    a cap on the upper end of the tube, the cap being removable to provide access to an interior of the tube.    
     
     
         2 . The drill bit of  claim 1 , wherein: 
 the cap comprises a skirt depending from a cover of the cap, the skirt being in engagement with at least a portion of the sidewall of the tube.    
     
     
         3 . The drill bit of  claim 1 , further comprising: 
 a cylindrical skirt depending from a cover of the cap, the skirt extending downward and terminating above the opening in the sidewall.    
     
     
         4 . The drill bit of  claim 1 , wherein: 
 the opening in the sidewall is located on an inner side of the tube relative to an axis of the bit, an outer side of the tube being free of openings; and wherein the drill bit further comprises 
 a skirt depending from a cover of the cap, the skirt extending downward and terminating below the opening, the skirt having two side portions that extend inwardly and terminate at spaced-apart inner edges, the side portions defining an open inner side that registers with the opening in the sidewall of the tube.  
   
     
     
         5 . The drill bit of  claim 1 , wherein: 
 the opening in the sidewall is located on an inner side of the tube relative to an axis of the bit, an outer side of the tube being free of openings; and wherein the drill bit further comprises 
 a skirt depending from a cover of the cap, the skirt extending downward and terminating below the opening, the skirt being generally U-shaped in transverse cross-section and having a curved outer portion and two parallel, straight side portions extending inwardly past the inner side of the tube, the straight side portions defining an open inner side that registers with the opening in the sidewall of the tube.  
   
     
     
         6 . The drill bit of  claim 1 , wherein: 
 the opening in the sidewall is located on an inner side of the tube relative to an axis of the bit, an outer side of the tube being free of openings; and wherein the drill bit further comprises 
 a skirt depending from a cover of the cap, the skirt extending downward and terminating below the opening, the skirt having a cylindrical outer portion and two concave inner portions that extend inwardly from the outer portion, the inner portions defining an open inner side that registers with the opening in the sidewall of the tube, the inner portions forming a throat area and a mouth, the throat area having a narrower width than the mouth.  
   
     
     
         7 . The drill bit of  claim 1 , wherein: 
 the tube has a plurality of deformable ribs that frictionally engage the passage in the body.    
     
     
         8 . The drill bit of  claim 1 , wherein: 
 a cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially.    
     
     
         9 . The drill bit of  claim 1 , further comprising: 
 a detent located on one of the cap and tube for engaging a recess located on the other of the cap and tube; and wherein 
 a cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially and disengage the detent from the recess.  
   
     
     
         10 . The drill bit of  claim 1 , further comprising: 
 a slot located in a cover of the cap, the slot being sized for engaging a tool for rotating the cap relative to the tube.    
     
     
         11 . A drill bit, comprising: 
 a body having at least one leg extending from the body, the body enclosing a bowl;    a passage extending through the body and the leg, the passage being in fluid communication with the bowl;    at least one tube extending from the passage and into the bowl, the tube having open upper and lower ends and being generally cylindrical, the lower end of the tube being inserted into the passage;    a plurality of elongated openings along a sidewall of the tube, each opening extending partially around the circumference of the tube on an inner side of the tube, the openings being in an axial column; and    a cap on the upper end of the tube, the cap having a skirt depending from a cover of the cap, the skirt being in engagement with at least a portion of the sidewall of the tube, the cap being removable to provide access to an interior of the tube.    
     
     
         12 . The drill bit of  claim 11 , wherein: 
 the skirt extends downward and terminates below the opening, the skirt being generally U-shaped in transverse cross-section and having a curved outer portion and two parallel, straight side portions extending inwardly past the inner side of the tube, the straight side portions defining an open inner side that registers with the openings in the sidewall of the tube.    
     
     
         13 . The drill bit of  claim 11 , wherein: 
 the skirt extends downward and terminates below the openings, the skirt having a cylindrical outer portion and two concave inner portions that extend inwardly from the outer portion, the inner portions defining an open inner side that registers with the openings in the sidewall of the tube, the inner portions forming a throat area and a mouth, the throat area having a narrower width than the mouth.    
     
     
         14 . The drill bit of  claim 11 , wherein: 
 the tube has a plurality of deformable ribs that frictionally engage the passage in the body.    
     
     
         15 . The drill bit of  claim 11 , wherein: 
 the cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially.    
     
     
         16 . The drill bit of  claim 11 , further comprising: 
 a detent located on one of the cap and tube for engaging a recess located on the other of the cap and tube; and wherein    the cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially and disengage the detent from the recess.    
     
     
         17 . The drill bit of  claim 11 , further comprising: 
 a slot located in the cover of the cap, the slot being sized for engaging a tool for rotating the cap relative to the tube.    
     
     
         18 . A drill bit, comprising: 
 a body having at least one leg extending from the body, the body enclosing a bowl;    a passage extending through the body and the leg, the passage being in fluid communication with the bowl;    at least one tube extending from the passage and into the bowl, the tube having open upper and lower ends and being generally cylindrical, the lower end of the tube being inserted into the passage;    a plurality of elongated openings along a sidewall of the tube, each opening extending partially around the circumference of the tube on an inner side of the tube, the openings being in an axial column; and    a cap on the upper end of the tube, the cap having a skirt depending from a cover of the cap, the skirt being in engagement with at least a portion of the sidewall of the tube, the cap being removable to provide access to an interior of the tube; and wherein    the cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially.    
     
     
         19 . The drill bit of  claim 18 , wherein: 
 the skirt extends downward and terminates below the opening, the skirt being generally U-shaped in transverse cross-section and having a curved outer portion and two parallel, straight side portions extending inwardly past the inner side of the tube, the straight side portions defining an open inner side that registers with the openings in the sidewall of the tube.    
     
     
         20 . The drill bit of  claim 18 , wherein: 
 the skirt extends downward and terminates below the openings, the skirt having a cylindrical outer portion and two concave inner portions that extend inwardly from the outer portion, the inner portions defining an open inner side that registers with the openings in the sidewall of the tube, the inner portions forming a throat area and a mouth, the throat area having a narrower width than the mouth.    
     
     
         21 . The drill bit of  claim 18 , wherein: 
 the tube has a plurality of deformable ribs that frictionally engage the passage in the body.    
     
     
         22 . The drill bit of  claim 18 , further comprising: 
 a detent located on one of the cap and tube for engaging a recess located on the other of the cap and tube; and wherein    rotation of the cap relative to the tube disengages the detent from the recess.    
     
     
         23 . The drill bit of  claim 18 , further comprising: 
 a slot located in the cover of the cap, the slot being sized for engaging a tool for rotating the cap relative to the tube.    
     
     
         24 . A drill bit, comprising: 
 a body having at least one leg extending from the body, the body enclosing a bowl;    a passage extending through the body and the leg, the passage being in fluid communication with the bowl;    at least one tube extending from the passage and into the bowl, the tube having open upper and lower ends and being generally cylindrical, the lower end of the tube being inserted into the passage;    an opening in the sidewall of the tube, the opening being located on an inner side of the tube relative to an axis of the bit, an outer side of the tube being free of openings; and    a cap on the upper end of the tube, the cap being removable to provide access to an interior of the tube, the cap having a cover and a skirt; and wherein    the skirt depends from the cover of the cap, the skirt extending downward and terminating below the opening, the skirt having two side portions that extend inwardly and terminate at spaced-apart inner edges, the side portions defining an open inner side that registers with the opening in the sidewall of the tube.    
     
     
         25 . The drill bit of  claim 24 , wherein: 
 the side portions are flat, planar sections that are parallel to each other.    
     
     
         26 . The drill bit of  claim 24 , wherein: 
 the side portions are concave sections that converge to form a throat and a mouth, the throat having a narrower width than the mouth.    
     
     
         27 . The drill bit of  claim 24 , wherein: 
 the tube has a plurality of deformable ribs that frictionally engage the passage in the body.    
     
     
         28 . The drill bit of  claim 24 , wherein: 
 the cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially.    
     
     
         29 . The drill bit of  claim 24 , further comprising: 
 a detent located on one of the cap and tube for engaging a recess located on the other of the cap and tube; and wherein    the cover of the cap and the upper end of the tube are defined by planes which are at angles to a central axis of the tube, such that rotation of the cap relative to the tube causes the cap to move axially and disengage the detent from the recess.    
     
     
         30 . The drill bit of  claim 24 , further comprising: 
 a slot located in the cover of the cap, the slot being sized for engaging a tool for rotating the cap relative to the tube.