Underground drilling apparatus

Abstract

A drilling apparatus can include a sonde housing that is elongated along a central longitudinal axis. The sonde housing has a length that extends along the central longitudinal axis from a proximal end of the sonde housing to a distal end of the sonde housing. The proximal end of the sonde housing is adapted for connection to a drill string and the distal end of the sonde housing includes a distal end face. The sonde housing further defines first and second sonde-housing fluid-delivery passages. The first and second sonde-housing fluid-delivery passages extend fluidly separately from one another throughout substantially an entire length of the sonde housing. The drilling apparatus can also include a rotary cutting tool that mounts to the distal end of the sonde housing. The rotary cutting tool can further define distinct first and second cutting-tool fluid-delivery passages. The first sonde-housing fluid-delivery passage can be in fluid communication with the first cutting-tool fluid-delivery passage. The second sonde-housing fluid-delivery passage can be in fluid communication with the second cutting-tool fluid-delivery passage.

1 . A drilling apparatus comprising:
 a sonde housing that is elongated along a central longitudinal axis, the sonde housing having a length that extends along the central longitudinal axis from a proximal end of the sonde housing to a distal end of the sonde housing, the proximal end of the sonde housing being adapted for connection to a drill string and the distal end of the sonde housing including a distal end face, the sonde housing further defining first and second sonde-housing fluid-delivery passages, the first and second sonde-housing fluid-delivery passages extending fluidly separately from one another throughout substantially an entire length of the sonde housing; and   a rotary cutting tool that mounts to the distal end of the sonde housing, the rotary cutting tool further defining distinct first and second cutting-tool fluid-delivery passages, the first sonde-housing fluid-delivery passage being in fluid communication with the first cutting-tool fluid-delivery passage, the second sonde-housing fluid-delivery passage being in fluid communication with the second cutting-tool fluid-delivery passage.   
     
     
         2 . The drilling apparatus of  claim 1 , wherein the first sonde-housing fluid-delivery passage and the first cutting-tool fluid-delivery passage define a first fluid connection therebetween, the second sonde-housing fluid-delivery passage and the second cutting-tool fluid-delivery passage defining a second fluid connection therebetween, the first fluid connection being fluidly distinct from the second fluid connection. 
     
     
         3 . The drilling apparatus of  claim 2 , wherein at least one of the first and second fluid connections defines a sealed fluid path. 
     
     
         4 . The drilling apparatus of  claim 3 , wherein each of the first and second fluid connections defines a respective, distinct sealed fluid path, the first and second fluid connections being defined by at least one pin and at least one respective pin-receiving opening configured to receive a corresponding pin therein, a given pin defining at least one pin fluid-delivery passage therethrough. 
     
     
         5 . The drilling apparatus of  claim 4 , wherein the first fluid connection is defined by a first given pin and a first given pin-receiving opening, the second fluid connection being defining by a second given pin and a second given pin-receiving opening, the first given pin being distinct from the second given pin, and the first given pin-receiving opening being distinct from the second given pin-receiving opening. 
     
     
         6 . The drilling apparatus of  claim 4 , further comprising an o-ring provided about the at least one pin adjacent the at least one respective pin-receiving opening. 
     
     
         7 . A drilling apparatus comprising:
 a sonde housing that is elongated along a central longitudinal axis, the sonde housing having a length that extends along the central longitudinal axis from a proximal end of the sonde housing to a distal end of the sonde housing, the sonde housing defining first and second fluid passages that extend from the distal end face proximally into the sonde housing, the first and second fluid passages having central axes that extend along the central longitudinal axis of the sonde housing; and   a rotary cutting tool that mounts to the distal end of the sonde housing, the rotary cutting tool including a head portion having a distal side and a proximal side, the distal side including a distal face in which a plurality of cutting teeth pockets are defined, the proximal side including a proximal face that opposes the distal end face of the sonde housing, the rotary cutting tool defining first and second fluid passages that extend distally from the proximal face and respectively co-axially align with the first and second fluid passages of the sonde housing;   wherein the first fluid passage of the sonde housing is fluidly connected to the first fluid passage of the rotary cutting tool, and the second fluid passage of the sonde housing is fluidly connected to the second fluid passage of the rotary cutting tool.   
     
     
         8 . The drilling apparatus of  claim 7 , wherein a sealed connection is provided between the first and second fluid passages of the sonde housing and the first and second fluid passages of the rotary cutting tool to prevent drilling liquid from leaking from the drilling apparatus. 
     
     
         9 . The drilling apparatus of  claim 8 , wherein the sealed connection includes a first pin and the first pin defines a first pin opening in fluid communication with the first fluid passage of the sonde housing and the first fluid passage of the rotary cutting tool such that the first fluid passages of the sonde housing and the rotary cutting tool pass through the first pin. 
     
     
         10 . The drilling apparatus of  claim 9 , wherein the sealed connection includes a second pin and the second pin defines a second pin opening in fluid communication with the second fluid passage of the sonde housing and the second fluid passage of the rotary cutting tool such that the second fluid passages of the sonde housing and the rotary cutting tool pass through the second pin. 
     
     
         11 . The drilling apparatus of  claim 10 , wherein the first and second fluid passages of the sonde housing are parallel passages, and the first and second fluid passages of the rotary cutting tool are parallel passages. 
     
     
         12 . The drilling apparatus of  claim 10 , wherein the first and second pins each have a first end respectively received in first and second pin openings of the sonde housing and a second end respectively received in first and second pin openings of the rotary cutting tool. 
     
     
         13 . The drilling apparatus of  claim 7 , wherein the proximal end of the sonde housing is adapted for connection to a drill string and the distal end of the sonde housing includes a distal end face. 
     
     
         14 . The drilling apparatus of  claim 7 , wherein the rotary cutting tool also includes a proximal extension that extends proximally from the proximal face of the head portion. 
     
     
         15 . The drilling apparatus of  claim 7 , wherein cutting teeth are mounted within the cutting teeth pockets of the rotary cutting tool. 
     
     
         16 . The drilling apparatus of  claim 12 , further comprising an o-ring provided about each of the first and second pins adjacent the first and second pin openings of the rotary cutting tool.