Pullback Assembly

Abstract

A drill string with a bit at one end is used to dig an underground borehole. When the drill string exits the borehole at a surface exit point, a pullback adapter is used to interconnect the bit with an above-ground utility line. A drilling rig retracts the drill string from the borehole. As the drill string is pulled back through the borehole, the trailing utility line follows along its underground path. As the utility line is pulled through the borehole, the connector biases the utility line to the center of the borehole. Such biasing reduces the risk of ensnaring of the connector and utility line by the borehole walls during the pulling process.

What is claimed is: 
     
         1 . An assembly, comprising:
 a bit, comprising:
 a body having an internal passage extending therethrough; and 
 a plurality of hardened cutting elements supported on the body; and 
   a connector extending through the passage and comprising:
 a first member having an elongate neck and an enlarged head formed at one end of the neck; and 
 a second member pivotally connected to the neck. 
   
     
     
         2 . The assembly of  claim 1  in which the bit is carried by a drill string and in which the pivotal connection of the second member coincides with the longitudinal axis of the drill string. 
     
     
         3 . The assembly of  claim 1  in which the neck is a rectangular prism. 
     
     
         4 . The assembly of  claim 1  in which the second member comprises a shackle. 
     
     
         5 . The assembly of  claim 1 , the bit having first and second legs adjoined at a bend, in which the passage is formed in the first leg and in which the second leg is configured for connection to a drill string. 
     
     
         6 . The assembly of  claim 5  in which each leg has opposed upper and lower surfaces in parallel relationship. 
     
     
         7 . The assembly of  claim 6  in which the lower surface of the first leg and the lower surface of the second leg form an included angle of greater than 180 degrees and less than 220 degrees. 
     
     
         8 . The assembly of  claim 7  in which the connector's second member is situated on the lower surface of the first leg. 
     
     
         9 . The assembly of  claim 1  in which the first leg has a pair of tapering side surfaces joining together at a point opposite the bend. 
     
     
         10 . The assembly of  claim 9  in which the side surfaces have hardened cutting elements. 
     
     
         11 . A system, comprising:
 a borehole formed in the ground;   the assembly of  claim 1  positioned within the borehole; and   a utility line attached to the connector's second member.   
     
     
         12 . The system of  claim 11  in which the utility line is a pipe. 
     
     
         13 . The system of  claim 11  in which the utility line is a cable. 
     
     
         14 . A kit, comprising:
 a bit, comprising:
 a body having an internal passage extending therethrough; and 
 a plurality of hardened cutting elements supported on the body; 
   a first connector element having an elongate neck sized to be closely received within the passage and an enlarged head formed at one end of the neck; and   a second connector element configured for pivotal connection to the neck.   
     
     
         15 . The kit of  claim 14 , the bit having first and second legs adjoined at a bend, in which the passage is formed in the first leg and in which the second leg is configured for connection to a drill string.