Boring or penetrating the earth – With signaling – indicating – testing or measuring – Indicating – testing or measuring a condition of the formation
Reexamination Certificate
1998-12-22
2001-01-23
Bagnell, David (Department: 3672)
Boring or penetrating the earth
With signaling, indicating, testing or measuring
Indicating, testing or measuring a condition of the formation
C175S056000, C175S293000
Reexamination Certificate
active
06176325
ABSTRACT:
The present invention relates to a moling apparatus and a ground sensing system therefor. More particularly, the present invention relates to a moling apparatus for forming tunnels to provide trenchless laying techniques.
Moling apparatus can be used for the purpose of, amongst other things, making holes in the ground for explosives say, driving piles or coring tubes into the ground, or making underground tunnels in the ground to receive pipes, cables or the like.
WO-A-95/29320 describes a moling apparatus comprising a housing having a head for penetrating ground disposed at the front end thereof, an anvil disposed in the housing and connected to the head, and a hammer disposed in the housing and spaced from the anvil by resilient restraint means. A vibrator unit, also provided within the housing, is spaced from the hammer and arranged to transfer vibration to the housing and the hammer. In a first mode of operation, vibration of the vibrator unit is transmitted to the housing for causing fluidization of the surrounding ground to allow progressive penetration of the apparatus. In a second mode of operation, the braking effect of the ground on the head causes the hammer to move against the resilient means and impact the anvil thereby driving the head through the ground. Thus, the moling apparatus self adjusts its mode of operation according to the type and condition of the ground being encountered. Indeed, the apparatus self adjusts within each mode, that is to say, it self adjusts the amplitude of the vibration of the vibrator unit or the magnitude of the impact.
The use of a moling apparatus for the above purpose of forming tunnels has particular importance because trenches do not need to be dug and because trenchless laying techniques are less labour intensive and harmful to the local environment. Unfortunately, the ground through which the moling apparatus must form tunnels can typically include many unknown underground obstacles such as cables, pipes, foundations, large rocks etc. Since the moling apparatus is effectively blind to such obstacles, the obstacle can either present an insurmountable barrier to the progress of the apparatus or the moling apparatus can cause undesirable and expensive damage to the obstacle, for example cracking underground pipes.
To avoid this problem, it is possible to consult ground plans or conduct sophisticated underground radar scanning tests as a form of ground sensing in order to map out an unobstructed route for the tunnel. However, this is time consuming, expensive, and ineffective. Furthermore, it does not provide any guarantee of successfully anticipating every underground obstacle. For the aforementioned reasons, moling apparatus have not been as extensively used for the purpose of tunnelling as would otherwise have been the case.
It is an object of the present invention to provide a simple ground sensing system for identifying ground characteristics to enable forewarning against obstacles present in the ground through which a projectile is passing.
It is another object of the present invention to provide a moling apparatus having a simple to use ground sensing system for providing forewarning against obstacles present in the ground through which the apparatus is tunnelling.
It is also an object of the present invention to provide a moling apparatus having means for steering to enable the apparatus to be directed around obstacles present in the ground through which the apparatus is tunnelling.
According to one aspect of the present invention there is provided a ground sensing system comprising:
sensing means located, in use, on a projectile being driven through ground by means of apparatus having a self adjustment between a vibration mode and a vibro-impact mode according to encountered ground resistance, the sensing means sensing the dynamic resistance of the ground that the projectile is passing through;
signal processing means for processing the output of said sensing means to provide a dynamic resistance waveform; and
waveform recognition means for correlating said dynamic resistance waveform with stored dynamic waveforms for identifying a ground characteristic.
In this way, it is possible to obtain forewarning of obstacles etc and the like in front of the projectile on which the sensing means is located. It will be appreciated that the term projectile can include a moling apparatus used for making holes in the ground, for driving piles or coring tubes into the ground, or for making underground tunnels in the ground.
In one embodiment, said waveform recognition means comprises a neural network system.
Such a network enables good matching with the stored waveforms and educated guesses in the case of less good matching.
In another embodiment, said waveform recognition means comprises a fuzzy logic system.
It is preferred that the system further comprises display means for providing an output signal indicative of the identified ground characteristic.
Thus, an operator can actively “see” what is happening at and in front of the projectile.
Conveniently, said display means displays the identified ground characteristic to an operator.
Thus, an operator is given quick feedback as regards obstacles and the like which the projectile is encountering.
Preferably, the system further comprises a store means containing a library of dynamic waveforms.
Consequently, the system can be readily used once the library contents are obtained.
In another embodiment, the system further comprises a store means for storing a library of dynamic waveforms in accordance with operator information and dynamic waveforms provided by said signal processing means.
Consequently, the system can be calibrated to real situations on the basis of the projectile on which the sensing means is located.
The present invention also encompasses a moling apparatus having a self adjustment between a vibration mode and a vibro-impact mode and including a ground sensing system as hereinabove defined.
Preferably, the moling apparatus comprises:
a head;
a vibrator unit connected to apply vibrations to the apparatus for providing said vibration mode of vibration driven penetration of ground;
a hammer vibrated by the vibrator unit;
an anvil;
resilient means provided to apply a separating force to keep the anvil and hammer a selected distance apart;
wherein the vibrator unit self adjusts to increase the amplitude displacement of the vibrated hammer according to increased penetration resistance from said ground until a point where said amplitude displacement overcomes said separating force by an amount resulting in the hammer striking the anvil for said vibro-impact mode of vibration and impact driven penetration of ground.
According to another aspect of the present invention there is provided a moling apparatus comprising:
an elongate shell;
a ground penetrating head located at a forward end of said shell; and
a fluid jet arrangement for projecting fluid at an area of ground adjacent to the apparatus.
Thus, it is possible to steer the apparatus.
Preferably, the fluid jet arrangement comprises one or more apertures provided adjacent the ground penetrating head and/or a rear end of the shell.
This enables convenient steering.
The fluid jet arrangement may comprise one or more apertures which are movable for projecting fluid in different directions relative to the apparatus.
In another embodiment, the movable apertures are mounted for annular rotation about an axis of the apparatus.
Preferably, the fluid jet arrangement comprises at least one aperture located at said ground penetrating head.
The present invention also encompasses a coring apparatus having a self adjustment between a vibration mode and a vibro-impact mode and including a ground sensing system as hereinabove defined.
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patent: 5549170 (1996-08-01), Barrow
patent: 5850884 (1998-12-01), Rodger et al.
patent: 28 47 128 (1980-05-01), None
patent: 0 05
Aberdeen University
Bagnell David
Walker Zakiya
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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