Auger boring machine with two-stage guidance control system

Abstract

An auger boring machine includes a two-stage guidance control system for controlling a pilot tube during formation of an underground pilot hole which is subsequently followed by an auger to form a larger hole for installation of underground pipe. The system includes a first stage guidance control mechanism for guiding the pilot tube during a first stage of driving the pilot tube and a second stage guidance control mechanism for guiding the pilot tube during a second subsequent stage of driving the pilot tube. The first stage mechanism typically includes a theodolite which allows for pilot tube control during the first several hundred feet of pilot hole formation. The second stage mechanism typically includes a sonar sensor such as a radio frequency receiver for sensing signals transmitted from within the pilot tube and allows for pilot tube control when the first stage mechanism is no longer functional.

1 . An apparatus comprising:
 an auger boring machine pilot tube;   a first stage guidance control mechanism for guiding the pilot tube during a first stage of driving the pilot tube; and   a second stage guidance control mechanism for guiding the pilot tube during a second subsequent stage of driving the pilot tube.   
   
   
       2 . The apparatus of  claim 1  further comprising a radio frequency transmitterwithin the pilot tube; and an illuminated target within the pilot tube. 
   
   
       3 . The apparatus of  claim 2  further comprising a radio frequency receiver separate from the pilot tube and operationally connected to the transmitter for receiving radio frequency signals therefrom. 
   
   
       4 . The apparatus of  claim 3  wherein the pilot tube has leading and trailing ends; and further comprising a line of sight passage formed in the pilot tube from the target to the trailing end; and a camera adjacent the trailing end of the pilot tube and aligned for viewing the target through the line of sight passage. 
   
   
       5 . The apparatus of  claim 4  further comprising a motor having a rotational drive operatively connected to the pilot tube for rotating the pilot tube. 
   
   
       6 . The apparatus of  claim 2  wherein the pilot tube has an outer surface; and further comprising a plurality of transmission openings formed in the pilot tube extending from the transmitter to the outer surface of the pilot tube. 
   
   
       7 . The apparatus of  claim 2  further comprising at least one lubrication through passage formed in the pilot tube extending alongside the transmitter and the target. 
   
   
       8 . The apparatus of  claim 2  wherein the pilot tube has leading and trailing ends; and the transmitter is disposed between the leading end and the target. 
   
   
       9 . The apparatus of  claim 8  further comprising a steering head on the leading end of the pilot tube; and wherein the transmitter is disposed between the steering head and the target. 
   
   
       10 . The apparatus of  claim 9  wherein the pilot tube comprises a first pilot tube segment which carries the transmitter and is removably connected to the steering head; and a second pilot tube segment which carries the target and is removably connected to the first pilot tube segment. 
   
   
       11 . The apparatus of  claim 1  wherein the first stage mechanism comprises a theodolite; and the second stage mechanism comprises a sonar sensor. 
   
   
       12 . A method comprising the steps of:
 (a) sensing a position of an auger boring machine pilot tube with a first sensing device during a first stage of driving the pilot tube to form a pilot hole in the ground;   (b) guiding the pilot tube during the first stage of driving the pilot tube in response to step (a);   (c) sensing a position of the pilot tube with a second sensing device during a second subsequent stage of driving the pilot tube; and   (d) guiding the pilot tube during the second stage of driving the pilot tube in response to step (c).   
   
   
       13 . The method of  claim 12  wherein step (a) comprises the step of sensing the position of the pilot tube with a theodolite. 
   
   
       14 . The method of  claim 13  wherein step (c) comprises the step of sensing the position of the pilot tube with a sonar sensor. 
   
   
       15 . The method of  claim 13  wherein step (c) comprises the step of sensing a radio frequency transmission from within the pilot tube. 
   
   
       16 . The method of  claim 15  wherein step (c) comprises the step of sensing the radio frequency transmission with an above ground radio frequency receiver. 
   
   
       17 . The method of  claim 12  wherein step (a) comprises the steps of transmitting light rays through the pilot tube from adjacent a leading end thereof to adjacent a trailing end thereof; and calculating the position of the pilot tube based on the light rays. 
   
   
       18 . The method of  claim 17  wherein step (c) comprises the step of sensing a radio frequency signal transmitted from the pilot tube adjacent its leading end. 
   
   
       19 . The method of  claim 12  wherein step (c) comprises the step of sensing a radio frequency signal transmitted from the pilot tube adjacent its leading end. 
   
   
       20 . The method of  claim 12  wherein each of steps (b) and (d) comprises the step of rotating the pilot tube and a steering head mounted thereon.