Moling system including transmitter-carrying mole for detecting and displaying the roll angle of the mole
First Claim
1. A molding system which is capable of giving an indication of mole location and depth comprising a rotatable mole the roll angle of which is required to be known, a radio sonde in the mole having a first transmit coil lying parallel to the lengthwise direction of the mole and a second transmit coil lying transverse to said direction, means indicating a battery and an oscillator for energising the transmit coils with alternating current with a phase difference between the coils, a receiver traversable above ground into a position in which the receiver can give an indication of the roll angle of the mole, and display means, associated with said receiver and located above ground, for displaying said roll angle.
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Accused Products
Abstract
A moling system comprises a mole (10) having a head (26) with a slant face at the leading end of a string of hollow rods (20). The rods are rotatable by a rig (12). The mole is an impact mole fed by air passed through the rods. While the mole rotates it travels approximately straight, but nonrotating it travels according to the direction of the slant face (28). The mole contains a radio sonde having one coil lying lengthwise and one transverse to the lengthwise direction of the mole. A receiver (22) is traversed across the ground to locate the radio sonde and display roll angle. The mole is stopped from rotating at the correct position when steering is required and powered without rotating to change course. An impact activated switch in the mole switches off the battery supply while the impact mechanism is activated.
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Citations
13 Claims
- 1. A molding system which is capable of giving an indication of mole location and depth comprising a rotatable mole the roll angle of which is required to be known, a radio sonde in the mole having a first transmit coil lying parallel to the lengthwise direction of the mole and a second transmit coil lying transverse to said direction, means indicating a battery and an oscillator for energising the transmit coils with alternating current with a phase difference between the coils, a receiver traversable above ground into a position in which the receiver can give an indication of the roll angle of the mole, and display means, associated with said receiver and located above ground, for displaying said roll angle.
Specification