Hole opener for horizontal directional drilling

Abstract

A hole opener for use with a drilling rig, the hole opener having a shaft configured for rotation by the horizontal directional drilling rig, a body coupled to the shaft for rotation with the shaft, a cutter coupled to the body for rotation relative to the body, and a lubrication system at least partially located within the body, the lubrication system operable to supply lubricant to the cutter. The lubrication system includes a duct in the body and a pressure regulator that increases and decreases a volume of the duct in response to the change in pressure of the lubricant to regulate a pressure of lubricant in the duct.

1 . A hole opener configured for use with a drilling rig, the hole opener comprising:
 a shaft configured for rotation by the horizontal directional drilling rig;   a body coupled to the shaft for rotation with the shaft;   a cutter coupled to the body for rotation relative to the body; and   a lubrication system at least partially located within the body, the lubrication system operable to supply a lubricant to the cutter, the lubrication system including,
 a duct in the body, and 
 a pressure regulator that increases and decreases a volume of the duct in response to a change in pressure of the lubricant to regulate a pressure of the lubricant in the duct. 
   
     
     
         2 . The hole opener of  claim 1 , wherein the pressure regulator includes a biasing member and a piston. 
     
     
         3 . The hole opener of  claim 2 , wherein the biasing member provides a biasing force at least partially opposing a pressure force of lubricant in the duct. 
     
     
         4 . The hole opener of  claim 2 , wherein the piston moves along a path parallel to an axis of rotation of the shaft to expand or contract the volume of the duct based on the pressure of the lubricant. 
     
     
         5 . The hole opener of  claim 1 , wherein the pressure regulator automatically increases and decreases the volume of the duct mechanically. 
     
     
         6 . The hole opener of  claim 2 , wherein the piston is sized for slidable engagement within a bore adjacent the duct, the bore having a greater diameter than the duct. 
     
     
         7 . The hole opener of  claim 6 , wherein the piston is sized to engage a shoulder formed at the interface of the bore and the duct. 
     
     
         8 . The hole opener of  claim 2 , wherein the biasing member engages the piston and a plug at an end of the bore opposite the duct. 
     
     
         9 . The hole opener of  claim 2 , wherein the piston includes a seal which interfaces with the bore to prevent lubricant from passing from the duct and past the piston, and the plug includes a seal to prevent lubricant from exiting the bore. 
     
     
         10 . A hole opener configured for use with a drilling rig, the hole opener comprising:
 a shaft configured for rotation by the horizontal directional drilling rig;   a body coupled to the shaft for rotation with the shaft;   a cutter coupled to the body for rotation relative to the body; and   a lubrication system at least partially located within the body, the lubrication system operable to supply a lubricant to the cutter, the lubrication system including,
 a duct in the body, 
 a first lubricant outlet in fluid communication with the duct, and 
 a second lubricant outlet in fluid communication with the duct. 
   
     
     
         11 . The hole opener of  claim 10 , wherein the lubrication system further comprises a lubrication inlet in fluid communication with the duct. 
     
     
         12 . The hole opener of  claim 11 , wherein the lubrication inlet is one of a group consisting of a grease nipple, Zerk fitting, or an Alemite fitting. 
     
     
         13 . The hole opener of  claim 11 , wherein a lubrication supply outlet is removably coupled to the lubrication inlet to supply lubricant to the duct. 
     
     
         14 . The hole opener of  claim 10 , wherein the first lubrication outlet provides lubricant to rollers located between the cutter and the body to facilitate rotation of the cutter relative to the body. 
     
     
         15 . The hole opener of  claim 10 , wherein at least one of the first lubrication outlet and the second lubrication outlet provides lubricant directly to the cutter to facilitate rotation of the cutter relative to the body. 
     
     
         16 . A hole opener configured for use with a drilling rig, the hole opener comprising:
 a shaft configured for rotation by the horizontal directional drilling rig;   a body removably coupled to the shaft for rotation with the shaft;   a cutter removably coupled to the body for rotation relative to the body; and   a lubrication system at least partially located within the body, the lubrication system operable to supply a lubricant to the cutter, the lubrication system including,
 a duct in the body, and 
 a pressure regulator that increases and decreases a volume of the duct in response to a change in pressure of the lubricant to regulate a pressure of the lubricant in the duct. 
   
     
     
         17 . The hole opener of  claim 16 , wherein the shaft further comprises a recess capable of removably engaging the body. 
     
     
         18 . The hole opener of  claim 17 , wherein the body is slidably received in the recess of the shaft. 
     
     
         19 . The hole opener of  claim 16 , further comprising an additional cutter removably coupled to the shaft. 
     
     
         20 . The hole opener of  claim 19 , wherein the additional cutter can be removed and replaced by welding a new additional cutter to the shaft when the additional cutter is worn or dull.