Moling system
First Claim
1. A moling system comprising a mole having a slant face at the leading end of the mole and means for obtaining indications representative of the plan and depth position of the mole and the angular position of the mole about a roll axis extending lengthwise of the mole, said mole comprising permanent magnet means having its magnetic axis transverse to said roll axis and producing a magnetic field extending away from the mole and penetrating into the ground surface in a zone about the mole and said indications obtaining means comprising magnetometer means transversable over the ground surface following the mole and operable in response to fluctuations of said magnetic field above the ground surface due to rotation of said mole about said roll axis to provide said indications representative of said angular position of the mole.
3 Assignments
0 Petitions
Accused Products
Abstract
A percussive-action mole 10 is energized by compressed air supplied through hollow rods 36 in a string 12 connected to the mole. A hydraulic motor 18 rotates the string and mole. The mole head 30 has a slant face 32 and a transverse permanent magnet 34. After each new rod is added to the string, the air is stopped to halt the mole which continues to be rotated. The field fluctuations from the magnet are detected by a magnetometer 24 using its probe at three positions 50, 52, 54 determiend by a triangular frame 22 placed flat on the ground. Calculations using the three readings each representing the distance of the magnet from the respective position on the frame enable the position and depth of the magnet to be determined. After completion, the passage 38 can be reamed to larger diameter to receive a gas pipe or other service.
105 Citations
12 Claims
- 1. A moling system comprising a mole having a slant face at the leading end of the mole and means for obtaining indications representative of the plan and depth position of the mole and the angular position of the mole about a roll axis extending lengthwise of the mole, said mole comprising permanent magnet means having its magnetic axis transverse to said roll axis and producing a magnetic field extending away from the mole and penetrating into the ground surface in a zone about the mole and said indications obtaining means comprising magnetometer means transversable over the ground surface following the mole and operable in response to fluctuations of said magnetic field above the ground surface due to rotation of said mole about said roll axis to provide said indications representative of said angular position of the mole.
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7. A moling system comprising a mole having a roll axis extending lengthwise of the mole and a slant face at the leading end of the mole, said mole further comprising permanent magnet means, comprising a single permanent magnet having its magnetic axis transverse to said roll axis, for producing a magnetic field extending away from the mole, and penetrating, in use, into the ground surface around the mole;
- means for rotating said mole so as to thereby cause rotation of said permanent magnet means around said roll axis; and
measuring means for producing indications representative of the plan and depth position of the mole and the angular position of the mole about said roll axis, said measuring means comprising magnetometer means, traversable over the ground surface following the mole and responsive to fluctuations of said magnetic field above the ground surface due to rotation of said mole about said roll axis, for providing said indications representative of said angular position of the mole. - View Dependent Claims (8, 9, 10, 11, 12)
- means for rotating said mole so as to thereby cause rotation of said permanent magnet means around said roll axis; and
Specification