Note: Descriptions are shown in the official language in which they were submitted.
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CABLE RECOVERY DEVICE AND SYSTEM
FIELD OF INVENTION
This invention relates to a trench plow blade for removing cable buried below
ground; and
in particular relates to apparatus for the removal of cable buried in the
ground which
includes a structure for loosening the ground above the buried cable. The
invention also
relates to a method of removing buried cable in the ground with a trench plow
blade;
including a method with a pre-survey cable location.
BACKGROUND TO THE INVENTION
There is a large amount of buried cable in the world. Much of this cable
includes valuable
metals such as copper or the like, the price of which has in recent years
increased
substantially. Some of this buried copper cable has been left in the ground to
be replaced
by optical fibre. The buried cable has substantial value because of its copper
content and is
therefore highly desirable to remove as well as for environmental reasons.
Most of the buried copper cable has been left in the ground as there has not
been an
effective way of removing substantial lengths of the cable. In some cases,
attempts have
been made to uncover the buried cable by digging a trench above the cable
using trenching
equipment and then in a separate operation digging down to the cable and
lifting it out.
Such system is labour intensive.
In other cases, attempts have been made to automate the location of the buried
cable by
using GPS systems or radio frequency means which have not been very effective.
Furthermore, some of the prior art equipment and methods have lacked
controllers which
are designed to keep the trenching equipment substantially over the buried
cable.
Furthermore, many of the prior art devices lack effective means for pulling
out the buried
cable without snapping or cutting of the cable. Finally, in some cases, the
ground has been
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compacted to such an extent that the prior art devices and methods have been
ineffective to
produce efficient cost-effective removal of the buried cable.
Various prior art has heretofore been issued for a variety of devices, systems
and methods
relating to cable trenching.
For example United States Patent No. 5190409 relates to a conventional cable-
laying
apparatus has been adapted for the removal of cable. A trenching plow blade is
towed
behind a bulldozer or the like. Mounted above the area of the blade is a
powered cable-
pulling assembly. Once an initial length of cable is excavated and routed to
the cable
pulling assembly, the equipment is advanced along the line of the cable to dig
the trench,
preferably just a small distance above the cable, such as about a foot, and
the cable pulling
assembly is driven to pull the cable from the ground behind the advanced
blade. The cable
may be routed to lie on the ground behind the advancing apparatus, or
alternatively may be
routed forward over the cab of the bulldozer onto a powered rewind reel. The
cable pulling
assembly includes a pulling wheel rotatably mounted to the blade support
assembly,
rotated by a hydraulic motor through a reduction gearbox. A series of rollers
are mounted
between two roller support arms. The roller support arms are connected to each
other and
pivotally mounted at one end to the blade support assembly, to rotate around a
pivot pin. A
hydraulic cylinder mounted between the blade support assembly and the roller
support
arms is operable to move the roller support arms to a closed position in which
the rollers
force the cable into the grooved portion of the pulling wheel, where teeth
defined by the
edges of squares rods into the cable to grip it securely for pulling.
Also United States Patent No. 8,209,136 shows a line locator includes a signal
detector to
detect signals from an underground line; an error modeler that models a phase
error in the
signal from neighboring underground lines; and an enhanced electromagnetic
field modeler
that provides a location of the underground line based on the signal and a
result from the
error modeler.
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Moreover United States Patent No. 5,741,088 relates to an excavation apparatus
comprising: a wedge member for driving through the ground and for slidingly
contacting
and lifting an overburden located beneath the surface of the ground
substantially toward
the surface of the ground; a driving attachment member for driving the wedge
member
below and substantially parallel to the surface of the ground; and a lateral
support member
attached to the wedge member for guiding the overburden across the wedge
member. The
apparatus may remove an existing utility line, install a new utility line,
apply bedding
material beneath a new utility line, or form a trench.
Furthermore United States Patent No. 4,014,175 relates to a cable and pipe
laying machine.
United States Patent No. 6,633,163 B2 teaches an excavator vehicle has sensors
thereon at
different heights. Each sensor may have a coil which is generally horizontal
and which
detects the magnetic field generated by a current in a buried conductor. By
detecting the
relative magnitudes of the component of the field parallel to the ground, as
detected by the
sensors, it is possible to determine whether or not the excavator vehicle is
proximate the
buried conductor. A warning may be generated, or the excavating tool of the
excavator
vehicle controlled, to prevent the excavating tool damaging the buried
conductor.
United States Patent No. 7,038,454 B2 shows a system and method for detecting
an
underground object using magnetic field sensing.
Furthermore United States Patent No. 7,759,824 B2 teaches a system and method
use
magnetic field sensing to detect underground objects for strike avoidance. The
system
detects magnetic field components for both passive distortions in the magnetic
field
indicative of a ferromagnetic object and active magnetic fields that are
impressed on an
object by a signal generator.
Moreover United States Patent No. 5,949,373 relates to a method for accurately
locating
buried utility conveyance, comprising the step of: burying the conveyance
while making at
least one global positioning satellite location measurement of the location of
the
conveyance during burial.
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United States Patent No. 4,430,022 shows an underground cable installing
apparatus and
method utilizing a multi-positionable plow blade
Finally United States Patent No. 5,214,868 relates to an apparatus for laying
an
underground member
It is an object of this invention to provide a more efficient trench plow
blade for removing
a cable below ground. Furthermore, it is another object of this invention to
provide more
efficient apparatus and systems for removal of the cable buried in the ground
including a
method for removing buried cable in the ground with a trench plow blade.
It is an aspect of this invention to provide a trench plow blade for removing
cable below
ground, comprising: a plow member having an upper end and a lower end where
the upper
end is adapted to be disposed above ground and the lower end adapted to be
disposed
below ground; a plow wedge disposed at said lower end and adapted to lift the
ground
above the cable when the trench plow blade is moved through the ground. By
lifting the
over burden, the width of the plow wedge box allows for a greater margin of
error.
It is another aspect of this invention to provide apparatus for the removal of
cable buried in
the ground comprising: a blade support assembly; a trenching plow blade
suspended from
the blade support assembly; structure for moving the blade support assembly
and said
trenching plow blade through the ground above the cable; structure for
orienting said
trenching plow blade in the ground substantially over said cable; radio
frequency means
for transmitting a signal to said buried cable, and for receiving a locate
signal;
microprocessing means communicating with said radio frequency means so as to
communicate with said orienting means to orient said trenching plow blade in
the ground
substantially over said cable; pulling means for pulling cable removed from
said ground as
the moving structure moves the blade assembly and trenching plow blade through
the
ground above the cable, said pulling means communicating with said radio
frequency
means and said pulling means including means for piercing said cable to
contact the metal
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in said cable so that said radio frequency means produces a locate signal in
said buried
cables.
Yet another aspect of this invention relates to a method of removing buried
cable in the
ground with the trenching plow blade comprising: loosening the ground above
the buried
cable; moving said trenching plow blade through the ground above the buried
cable;
pulling the buried cable out of the ground.
These and other objects and features will now be described in relation to the
following
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevational view of the apparatus for the removal of cable
buried in the
ground.
Figure lA is a side elevational view of Figure 1 taken from the left side.
Figure 1B is a side elevational view of Figure 1 taken from the left where the
vehicle 8 is
on an angled shoulder.
Figure 2 is a top view of Figure 1.
Figure 3 is an isolated front view of the pulling structure.
Figure 3A is a cross-sectional view of Figure 3 taken from the lines 3A-3A.
Figure 3B is an exploded view of a portion of Figure 3A.
Figure 2A is a side elevational view taken from the right of Figure 2.
Figure 2B is a side elevational view taken from the right of Figure 2 on the
shoulder.
Figure 4 is a front elevational view of the plow.
Figure 5A is a front elevational view of one embodiment of the plow.
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Figure 5B is a cross sectional view of Figure 5A.
Figure 6 is a perspective view of a trenching plow blade.
Figure 7 is a side elevational view of another embodiment of the trench plow
blade.
Figure 8a, 8b, 8c and 8d illustrates another embodiment of the trench plow
blades.
Figure 9 is another embodiment of the trench plow blade.
Figure 10 illustrates other embodiments of the trench plow blade.
DETAILED DESCRIPTION OF THE INVENTION
The invention to be described herein shows
Like parts have been given like numbers throughout the figures. In the
drawings,
embodiments of the invention as illustrated by way of example, it is expressly
understood
that the description and drawings are only for the purpose of illustration and
as an aid to
understanding, and are not intended as a definition of the limits of the
invention.
Figure 1 generally illustrates apparatus 2 for the removal of cable 4 buried
in the ground 6.
In particular, the apparatus 2 includes a moving means or vehicle 8 such as a
bulldozer or
the like having a blade support assembly 10. A trenching plow blade 12 is
suspended from
the blade support assembly 10 as shown. The trench plow blade 12 includes a
plow
member 14 having an upper end 16 and a lower end 18 where the upper end 16 is
adapted
to be disposed above ground 6 and the lower end 18 is adapted to be disposed
below
ground 6. A plow wedge 20 is disposed at the lower end 18 and adapted to lift
the ground
6 above the cable 4 when the trench plow blade 12 is moved through the ground
by the
moving means 8.
The trench plow blade 12 includes a channel 22 for guiding a cable 4 removed
from the
ground 6.
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The trench plow blade 12 can also include a conduit 24 for receiving air or
water to the
plow wedge 20 for loosening or lubricating the ground above the cable so as to
make it
easier for the plow wedge 20 to move through the ground 6 and easier to remove
the buried
cable 4. In other words the air or water will loosen the ground in the
vicinity of the cable 4.
As best seen in Figure 5A, 5B and 6, the plow wedge 20 has an angled front
face 26 which
is adapted to cut to the ground as the plow member 14 is moved. In other words
the
ground will lift up and over the front face 26 as the plow wedge moves through
the ground
in the direction of arrow A. The plow wedge 20 is generally hollow having a
top surface
28 with two space sides depending from the edges of the top surface 28. The
plow wedge
20 also includes an open back 32 as shown. The top surface 28 can accommodate
the
channel 22 adapted to receive the pulled cable as well as the conduit 24. As
the plow
member 14 and the plow wedge 20 is moved through the ground by the moving
means 8 in
direction A. The ground 6 will tend to be pushed upwardly thereby relieving
the pressure
on the buried cable 4 making it easier to be removed.
In another embodiment of the invention as shown in Figure 5B, the plow member
14 is
separate from the plow wedge 20 and can be reciprocally moved or vibrated
between a first
position B1 and a second position B2 so that the plow wedge 20 loosens the
ground above
the cable 4. Alternatively, at least one disk 34 can be disposed to the side
of the plow
member 14 and adapted to rotate and cut into the ground so as to loosen the
ground above
or to the side of the buried cable 4. Figure 1 A shows the use of two round
disks 34
disposed on other side of the plow member 14 so as to cut into the ground
above the buried
cable.
A further embodiment of a trench plow blade is illustrated in Figures 8A, 8B
and 8C. In
particular Figure 8A illustrates a perspective view of a plow member 14 having
a side
scoop 15. The side scoop 15 is spaced from the plow member 14 as illustrated
in Figure
8B. Figure 8B is a back view of Figure 8A. The rear or back is open as shown
in Figure
8B with connecting rod like members 17. There is a solid plate 7 near the top
thereof. The
lower end of the side scoop 15 and the lower end 18 of the blade member 14
includes a
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plow wedge 20 as shown. The upper end of the plow member 14 includes two holes
11
which are adapted to be connected to the blade member frame 60 which also has
aligned
holes 59 and 61 as shown. With the embodiment shown in Figures 8A, 8B and 8C
the side
scoop 15 will loosen the ground in the vicinity as the blade member 14 is
pulled though the
ground; where such loosened ground will exit through the openings created by
the
connecting members 17.
Yet another embodiment of the invention is shown in Figure 9 whereby the blade
member
14 comprises two spaced blade members 14A and 14B which are connected together
by
members 17 as shown. The lower end 18 of blade members 14A and 14B include
plow
wedge members 20A and 20B. The trench plow blade illustrated in Figure 9
operates in a
similar fashion to that described in relation to Figures 8A, 8B and 8C.
Other embodiments of the trench plow blade 12 are illustrated in figures
10A,10B,10C,10D, and 10E. The embodiment shown in Figure 10E includes
reinforcing
bars or plates 17.
The invention as described herein also includes means 40 for orienting the
plow member
14 and plow wedge 20 in a substantially vertical position over the buried
cable 4 as the
trench plow blade 12 is moved through the ground.
For example, much of the buried cable 4 has been laid close to a road or a
highway
particularly in the region of the shoulder on either side of the road or
highway. Typically
the shoulder 42 is disposed at an acute angle A from the road or highway 36 as
best shown
in Figure 1B. Accordingly, the orienting means 40 which in one embodiment
comprises of
a hydraulic cylinder 44 is activated so as to move an orientating plate 46 as
shown so that
the trench plow blade 12 is substantially vertically orientated over the cable
4 even though
the vehicle 8 and the vehicle tracks 48 may be disposed at an acute angle a
since they ride
on the shoulder 42 as shown. Other orientating means 40 can be utilized so as
to
compensate for the vertical disposition of the plow member 14 as the vehicle 8
moves over
uneven ground.
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Fig 2B similarly shows the front sensors 110 and 112 (that senses the cable 4
) will
similarly rotate so as to be substantially vertical by rotation of the gyro
sensor 41
The invention as described herein also includes micro processing means 50
which is
comprised of a computer, central processing unit, or the like. The micro
processing means
50 is either wired to sensors to be described herein or communicates
wirelessly with the
various sensors to be described herein. The central processing unit 50
communicates with
a level sensor 52. In one embodiment the level sensor 52a consists of a
gyroscope that
monitors angulation relative to the horizon. When the level sensor 52 or 52a
senses that the
vehicle 8 is at an angle a the sensor 52 sends a signal to the micro
processing means 50 to
thereby activate the hydraulic cylinder 44 so as to rotate the orientating
plate 46 in a
substantially vertical position whereby the axis c of the plow member 14 is
moved to the
substantially perpendicular position as shown in Figure 1B. Alternatively the
orientation
can be controlled by a gyro 52; or manually override the system as more fully
particularized herein. The sensor 52 can be a rotational sensor at pivot point
53 or other
sensor to determine the vertical orientation of the plow member 14.
The orientating means 40 also includes a second hydraulic cylinder 54 having
one end 56
attached to the blade support assembly 10 and another end 58 attached to a
blade member
frame 60 which is attached to the blade member 14 so as to pull or push the
blade member
14 in the direction of arrows D1 and D2. The central processing unit 50
receives wireless
signals from a sensor 62 disposed at the pivot point 63 so as to adjust the
position of the
blade member 14 in a pre-determined disposition. In other words the sensor 63
determines
the rotational disposition at pivot point 63. However other types of sensors
62 could be
used.
The orientating means 40 can also include a third hydraulic cylinder 64 which
is pivotally
mounted on the blade support assembly 10 so that the hydraulic piston 66 can
be moved in
a direction of El and E2 and thereby move to the plow member 14 in a pre-
selected
position which is controlled by a computer 50 after receiving a wireless
signal from a
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sensor 68. In particular, the second hydraulic cylinder 54 and third hydraulic
cylinder 64
are utilized to adjust the depth of penetration of the plow wedge 20 into the
ground 6.
The apparatus 2 includes positioning hydraulic cylinders 63 and 65 which
communicate
with sensors 67 and 69 as well as micro processing means 50 so as to control
the left to
right or lateral positioning of the trench plow blade 12. A joy stick
connected to a display
51 on the central processing unit 50 may be utilized so as to control the
lateral motion of
the trench plow blade 12. The display 51 may be a touch screen display for
human
interface for controlling the orientation of the trench plow blade 12 over the
cable 4.
The apparatus 10 also includes means 70 for pulling the cable 4 from the
ground 6 as the
vehicle or moving means 8 moves the blade assembly 10 and trench plow blade 12
through
the ground 6 above the cable 4.
In one embodiment the pulling means 70 comprises a pulley frame 72 having
drive
pulleys 74 and 76 and an idler pulley 78. The idler pulley 78 includes a
pressure adjusting
means 82 having an axis 80. In one embodiment the pressure adjusting means
comprises
another hydraulic cylinder 82. The idler pulley 78 is connected to another
hydraulic
cylinder 82 that communicates with the central processing unit 50 so as to
exert a desired
force onto the cable 4 as the drive pulleys 74 and 76 rotate in a direction to
pull the cable 4
out of the ground. It should be understood that pulleys 74 or 76 or both could
be drive
pulleys , and pulley 78 an idler pulley within the teachings of this
application.
The drive pulleys 74 and 76 include piercing means 84 which in one embodiment
comprises teeth 84 that penetrate the outside 86 of the cable 4 so as to make
contact with
the metal within the cable 4.
The apparatus 2 also includes radio frequency means 90 for transmitting a
signal to the
buried cable 4 and for receiving a locate signal. The micro processing means
50
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communicates with the radio frequency means 90 so as to communicate with the
orientating means 40 to orient the trench plow in the ground substantially
over the cable 4.
The pulleys 74, 76 and 78 are adapted for rotation about their axis relative
to the pulley
frame 72. The pulley 78 includes an insulating sleeve 92 which is comprised
from nylon
or the like so as to be non-electrically conductive. The pulley 78 also
includes a housing
94 which contains a brush 96 and a spring 98 so as to urge the brush 96
against the surface
of pulley 78 as it rotates. A wire connector 100 is attached to the brush 96
at one end
thereof and to the transmitter of the radio frequency means 90. Accordingly,
as the teeth
84 on the drive pulley 74 pierce the outer surface of the cable 4 as the cable
is being
removed from the ground the teeth contact the metal sheeth 86 in the cable 4.
A radio
frequency signal from the radio frequency means 90 is communicated by wire
100, or
alternatively, by wireless means with the brush 96 which makes electrical
contact with the
pulley 74 so as to induce or provide a signal within the cable 4 which is
picked up by the
receivers of the radio frequency means 90 so as to generate a signal within
the cable
thereby permitting the micro processing means 50 to determine the location of
the cable 4
and guide the various hydraulic cylinders to move the blade member 14
particularly the
blade wedge 20 over the cable in a more efficient fashion.
Sensors 110 and 112 pick up the radio frequency from the cable 4 and
communicate with
the micro processing means 50 which guides the orientating means 40 so that
the plow
wedge 20 is substantially over the cable 4. Two sensors 110 and 112 are
utilized so as to
more accurately read the location of the buried cable 4.
More particularly the radio frequency means 90 induces a signal into the wire
or cable 4.
The frequency and method of connection is dependent on the wire type, the
ground density
and composition, and surrounding environment.
In operation the tractor or vehicle 8 is positioned over the wire or cable 4.
The micro
processing means 50 can include a Human Machine Interface (HMI) display 51
which
displays the cable 4 position; whereby the operator can manually align the
vehicle 8 with
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the cable 4. In one embodiment a joy stick can be utilized to provide manual
positioning
of the trench plow blade 12 which is controlled by the micro processing means
50 through
the display 51.
Encoders 43 and 45 can be mounted at the rear of the vehicle 8 or closer to
the front of the
monitoring frame 55 as shown by 43a and 45a.. The encoders 43 and 45 are
mounted at
the bottom of the mounting frame 55 at an angle that converges to locate the
cable 4
especially when the bulldozer 8 turns the back of the frame 55 will have a
tendency to
move to the "side" of the cable 4. The encoders 43 and 45 will assert in "re
orientating"
over the cable 4 adjacent to the trench plow blade 12 to provide right to left
hand or lateral
position detection. The data from the encoders 43 and 45 is sent to the micro
processing
means 50 and is used for plow position feedback.
The microprocessing means 50 includes the appropriate application software
having
directions for the activation of the orienting means 40 and radio frequency
means 90
according to predetermined parameters.
In another embodiment of the invention a GPS system may be utilized to locate
the
position of the cable 4. More particularly a hand held GPS cable locator (
which in one
embodiment can comprise a radio tech locator computer) may be held by an
individual
who will walk over the position of the buried cable 4. The hand held GPS
device in
association with a GPS system digitally stores the location of the buried
cable which data
may then be downloaded into the micro processing unit 50 as a pre survey. This
downloaded information or data may then be used by the central processing unit
to control
the various orientation means previously discussed as well as the hydraulic
cylinders. In
particular, the invention includes a valve body 53 having valves that
communicate with the
cylinders. The valve body 53 includes manually operable valves to move the
cylinder as
well as solenoid switches which are electronically or digitally controlled by
the micro
processor 50.
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In another embodiment a current or radio frequency may be injected into the
cable 4 by a
conductive method which consists of connecting a signal directly to the cable
4 through
means of a clip. This method will incorporate frequencies in the range of 500
kHz to 100
kHz. An example of this method consists of a device sold under the trade-mark
Metrotech
or Radiotech which are manual cable locators. Alternatively these devices can
be modified
by adding a GPS locator and data memory cards for storing the location data.
The
modified devices can have download and upload ports to download or upload data
to the
microprocessor 50.
Alternatively in another embodiment the individual may spray paint portions of
the surface
of the ground to provide a "rough" positioning of the buried cable.
Alternatively the signal can be injected by an inductive clamp method whereby
the signal
will be applied through an inductive clamp. Both ends of the cable 4 will be
grounded.
This method will incorporate frequencies in the range of 10 kHz to 100 kHz.
The cable tracking receivers 110 and 112 at the front, and/or the tracking
system at the rear
43 and 45 or 43a and 45a. previously described will receive data from the
cable tracking
receiver that is sent to the micro processing means 50 for wire position
calculation. The
wire position data is sent to the Human Machine Interface touch screen
display. A vehicle
operator uses this information to steer and maintain the vehicle 8 over the
cable 4.
Two cable tracking receivers 120 and 122 mounted at the rear of the vehicle 8
can be set
apart for example by two feet or the like with for example a ten degree
adjustable angle
adjustment. Other spacing and degree adjustment angles then can be utilized.
Data from
cable tracking receivers 120 and 122 is sent to the micro processing means 50
for wire
position calculation and Human Machine Interface touch screen display 51. The
wire
position data will be used to maintain the correct lateral or right and left
position of the
trench plow blade 12 over the cable 4.
The cable 4 depth tracking receiver is mounted to the front of the trench plow
blade 12 to
track and adjust the plow depth. Data from the cable depth tracking receiver
is sent to the
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micro processing means 50 for wire depth calculation and Human Machine
Interface touch
screen display. The wire data will be used to maintain the correct plow depth
over the
wire.
Accordingly, the invention as described herein relates to apparatus 2 for the
removal of
cable 4 buried in the ground 6 which comprises a blade support assembly 10, a
trenching
plow blade 12 suspended from the blade support assembly 10, means 8 for moving
the
blade support assembly 10 and the trenching plow blade 12 through the ground 6
above the
cable 4; and orientating means 40, for orientating the trenching plow blade 12
in the
ground 6 substantially over the cable 4. A radio frequency means 90 transmit a
signal to
the buried cable 4 and for receiving a locate signal. Micro processing means
50
communicate with the radio frequency means 90 so as to communicate with the
orientating
means 40 to orient the trench plow 12 in the ground 6 substantially over the
cable 4.
Pulley means 70 pulled cable 4 from the ground 6 as the vehicle 8 moves the
blade
assembly 10 and the trench plow blade 12 through the ground 6 above the cable
4 where
the pulley means 70 communicates with the radio frequency means 90. The pulley
means
70 include piercing means 84 for piercing the cable 4 to contact the metal in
the cable 4 so
that the radio frequency means 90 produce a locate signal in the buried cable.
The invention as described herein also relates to a method of removing buried
cable 4 in
the ground 6 with a trench plow blade 12 which comprises; moving the trench
plow blade
12 through the ground 6 above the buried cable 4; loosening the ground 6 above
the buried
cable 4; pulling the buried cable 4 out of the ground.
The cable 4 can be wound on a spool as it is being pulled out of the ground or
alternatively
the buried cable may be first pulled out of the ground and laid on top of the
ground and
gathered thereafter about a spool.
The vehicle or tractor 8 is positioned over the cable 4. The Human Machine
Interface
touch screen 51 displays the cable position 4. The operator manually aligns
the vehicle
over the cable 4 by use for example of a steering wheel or joy stick as
previously
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mentioned. The operator then manually adjusts the plow to the correct depth
and position
over the cable 4. The vehicle 8 is set to the desired speed. The operator then
can select
automatic operation.
The operation the operator steers the vehicle to maintain the pre-track
tracking receiver
over the cable 4. For example a circle on the display 51 can be manually moved
by the
operator so as to centre over cross-hairs on the display that represents the
cable 4 location.
The Human Machine Interface touch screen display 51 continually displays the
wire or
cable position and depth. The micro processing means 50 maintains the plow
position over
the cable 4.
The invention as described herein relates to apparatus for recovering buried
cable or
conductors abandoned by utilities or other entities that have left buried
conducting wires.
The apparatus minimizes the amount of burden that must be displaced from above
the
conductor or cable by tracking the position of the conductor or cable in real
time using
electronic wire position detection. The apparatus uses a signal generator to
produce
tracking current or frequency that is injected into the buried cable 4. The
control system or
micro processing means of the apparatus 2 is configured to position the plow
which is
powered and pulled by the vehicle 8 such that the furrow that is created by
the plow is
controlled to remain centered on the buried conductor or cable. The related
apparatus for
collecting the conductor uses power from its power unit to lift the conductor
using the
plowed furrow at a controlled tension and stores the conductor for transport.
The apparatus 2 described herein provides improved accuracy. Also the
invention
described will generally increase the speed and accuracy of the cable removal
as compared
to the prior art. Furthermore the apparatus 2 reduces the likelihood of
breaking the
recovered cable or conductor 4 by virtue of alignment of the extraction
direction with the
furrow and control of the lifting tension applied to the buried cable 4. There
is an
environmental advantage in removing cable from the ground. Also for every
pound of
copper removed from the ground you eliminate the need for refining the copper
metal
which has a negative impact on the environment.
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Moreover the control strategy for the apparatus 2 utilizes an injected test
signal on the
buried cable 4 to position the plow at the correct depth and follow the buried
path of the
buried cable 4 as the vehicle 8 pulls the plow 12.
Furthermore electric isolation of the cable 4 extraction and transport
apparatus 2 from the
plow 12 and the vehicle 8 avoids stray signal interference with position
detection.
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