Inground boring technique including real time transducer

Claim 1

In a boring apparatus including a boring tool designed to bore a hole through the ground, a drill string connected at one end with said boring tool and extending from there to ground level through the hole being formed, and means for urging the boring tool and drill string forward as the hole is being made, the improvement comprising: (a) information providing means carried by said boring tool for generating an AC signal at a frequency from about 1 KHz to about 100 KHz, containing inground information between a pair of output terminals; and (b) means for transmitting said inground information containing signal to an above-ground location where said information can be extracted from the signal, said transmitting means including electrically conductive structural means exposed to and capable of contacting the ground surrounding the boring tool as the boring tool moves through the hole being formed, at least a section of said drill string which is electrically conductive to carry said signal and which is electrically insulated from but physically connected with said structural means, means for electrically connecting one of said pairs of output terminals of said information providing means directly to said section of said drill string without inductive coupling, and means for electrically connecting the other of said output terminals directly to said structural means, whereby said drill string section serves to carry said AC signal and said structural means and surrounding ground are used as a signal return path.

Claim 9

A system in which a boring tool is urged through the ground by means of a drill string connected to and extending rearwardly from the boring tool in order to form a hole in the ground, an arrangement for obtaining inground information at the boring tool as the boring tool forms said hole, said arrangement comprising: (a) transducer means carried by said boring tool for generating an AC signal having a frequency from about 1 KHz to about 100 KHz between first and second output terminals, said signal containing said information; (b) means for transmitting said information containing signal to an above-ground location, said transmitting means including (i) at least one electrically continuous section of drill string which is electrically conductive to carry said signal, (ii) electrically conductive structural means which is electrically insulated from but physically connected with said drill string section and which is exposed to and capable of contacting the ground surrounding the boring tool as the boring tool moves through the hole being formed and, (iii) means for electrically connecting said first output terminal of said transducer directly to the electrically conductive continuous section of said drill string without inductive coupling and (iv) means for electrically connecting said second output terminal at said transducer directly to said structural means whereby said electrically conductive drive string section serves to carry said AC signal to said above ground location and said structural means and ground serves as a signal with return path; and (c) means located at said above ground location for acting on said AC signal and extracting said information from the AC signal.

Claim 10

A system in which a boring tool is urged through the ground by means of a drill string connected to and extending rearwardly from the boring tool in order to form a hole in the ground, an arrangement for obtaining inground information at the boring tool as the boring tool forms said hole, said arrangement comprising: (a) transducer means carried by said boring tool for generating an AC signal having a frequency from about 1 KHz to about 100 KHz between first and second output terminals, said signal containing said information; (b) means for transmitting said information containing signal to an above-ground location, said transmitting means including (i) at least one electrically continuous section of drill string which is electrically conductive to carry said signal, (ii) electrically conductive structural means which is electrically insulated from but physically connected with said drill string section and which is exposed to and capable of contacting the ground surrounding the boring tool as the boring tool moves through the hole being formed and, (iii) means for electrically connecting said first output terminal of said transducer directly to the electrically conductive continuous section of said drill string without inductive coupling and (iv) means for electrically connecting said second output terminal at said transducer directly to said structural means whereby said electrically conductive drive string section serves to carry said AC signal to said above ground location and said structural means and ground serves as a signal with return path; and (c) means located at said above ground location for acting on said AC signal and extracting said information from the AC signal.