초록 ▼

A system in which a boring tool is urged through the ground by means of a drill string in order to form an underground hole is disclosed herein along with an arrangement for obtaining certain information at the boring tool during operation of the boring tool. That arrangement includes a transducer c

A system in which a boring tool is urged through the ground by means of a drill string in order to form an underground hole is disclosed herein along with an arrangement for obtaining certain information at the boring tool during operation of the boring tool. That arrangement includes a transducer carried by the boring tool for generating an AC signal containing desired information and means for connecting the transducer directly to the drill string and to the surrounding ground for transmitting the information containing signal to an above ground location.

대표청구항 ▼

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 bei

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.