Note: Descriptions are shown in the official language in which they were submitted.
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Title: CONDUIT LAYING MACHINE
FIELD OF THE INVENTION
[0001] The present invention relates to conduit laying machines and
more particularly to conduit laying machines that lay conduits, such as high-
voltage electrical cables, and that discharge base material around the
conduits.
BACKGROUND OF THE INVENTION
[0002] Laying electrical cables underground is typically accomplished by
digging a trench and laying the cable in the trench. The trench may be dug
using a backhoe loader or the like and the cable may be laid in the trench
manually, while being fed from a reel that is mounted on a truck. Typically,
such work is slow, and relatively labour intensive.
[0003] Systems have been proposed to lay cable in an open trench,
however, such systems suffer from a variety of shortcomings. For example, in
some instances, no means for protecting the cable in the trench is provided.
Accordingly, the cable is at risk of puncture or other damage from exposed
rocks and the like in the trench.
[0004] It would be advantageous to provide a system that lays cable or
other types of conduit while protecting it from damage.
SUMMARY OF THE INVENTION
[0005] In a first aspect, the invention is directed to an assembly for laying
conduit, including a trench former, a conduit feed system and a base material
handling system. The trench former is configured for forming a trench. The
conduit feed system includes a conduit feed passage having a conduit feed
passage inlet for receiving at least one conduit and a conduit feed passage
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outlet positioned to deposit the at least one conduit in the trench. The base
material handling system includes a base material hopper and at least one
base material passage. The at least one base material passage is positioned
to receive base material from the base material hopper and to discharge base
material in the trench around the at least one conduit. Optionally, the
invention
is directed to a conduit laying system that is made up of the aforementioned
assembly and a vehicle for driving the assembly. Optionally, depending on the
type of conduit that is to be laid, the conduit laying system may further
include a
conduit reel holder mounted to the vehicle for holding one or more reels of
conduit. The at least one base material passage may be configured in a way to
inhibit the base material from bridging therein. For example, the at least one
base material passage may have a cross-sectional area that increases in a
downward direction. Additionally or alternatively, the base material passage
may extend in a downward direction (not necessarily a strictly downward
direction) and may have a lateral spacing and a longitudinal spacing, whereby
the lateral and longitudinal directions are relative to the direction of
travel of the
base material handling system. One of the lateral and longitudinal spacings
may be shorter than the other. The shorter of the spacings may increase in a
downward direction.
[0006] In a second aspect, the invention is directed to a conduit laying
system including a trench former, a conduit feed system and a base material
handling system. The trench former is configured for forming a trench and
includes a vibration mechanism. The conduit feed system includes a conduit
feed passage having a conduit feed passage inlet for receiving at least one
conduit and a conduit feed passage outlet positioned to deposit the at least
one
conduit in the trench. The base material handling system includes a base
material hopper and at least one base material passage. The at least one base
material passage is positioned to receive base material from the base material
hopper and to discharge base material in the trench around the at least one
conduit. The base material in the hopper and/or in the at least one base
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material passage may be subject to vibration from the vibration mechanism.
The at least one base material passage may be configured to inhibit bridging
of
base material therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention will now be described by way of example
only with reference to the attached drawings, in which:
[0008] Figure 1 is a perspective view of a system for creating a trench
and for laying one or more conduits in the trench in accordance with an
embodiment of the present invention;
[0009] Figure 2 is another perspective view of the system shown in
Figure 1 showing the front of the system;
[0010] Figure 3 is a side view of a portion of the system shown in Figure
1;
[0011] Figure 4 is a sectional side view of a portion of the system shown
in Figure 1;
[0012] Figure 5 is a another perspective view of the system shown in
Figure 1 showing the rear of the system;
[0013] Figure 6 is a plan view of the portion of the system shown in
Figure 4;
[0014] Figure 7 is a cutaway perspective view of selected components
from the portion of the system shown in Figure 4;
[0015] Figure 8 is a sectional perspective view along section line 8-8
shown in Figure 4; and
[0016] Figure 9 is a perspective end view of the portion of the system
shown in Figure 4.
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DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference is made to Figure 1, which shows a system 10 for
creating a trench 11 and for laying one or more conduits 12 in the trench 11
in
accordance with an embodiment of the present invention. The system 10
shown in Figure 1 lays three conduits 12. It is however, possible for a system
in accordance with an embodiment of the invention to lay some other number
of conduits 12, such as one conduit 12, two conduits 12 or more. The conduits
12 may be any suitable type of conduits. For example, the conduits 12 may be
high voltage, electrical conduits (which may also be referred to as electrical
cables), wherein each conduit 12 carries one phase of a three-phase electrical
supply.
[0018] The system 10 also discharges a base material 14 around the
conduits 12 in the trench 11, which supports the conduits 12 and assists in
protecting the conduits against damage from sharp rocks and the like that may
be exposed when the trench 11 is formed.
[0019] The base material 14 may be any suitable base material, such as,
for example, a granular particulate material, or a slurry that hardens after a
period of time. Some examples of base materials 14 that may be used include
sand, concrete, cement, and particulate material that absorbs moisture from
the
ground around it to harden into a solid.
[0020] The system 10 includes a conduit reel support 16, a trench former
18, a base material handling system 20, a conduit feed system 22 and a
vehicle 24. In the embodiment shown in Figure 1, the conduit reel support 16
is
positioned at the front of the vehicle 24 and is configured to hold three
reels 26
(best seen in Figure 2) of conduit 12. The front of the vehicle is shown at
27.
The conduit reel support 16 may include a plurality of arms 28 having ends 30
that include cradles 32 for holding the shafts, shown at 34 (see Figure 2) of
the
conduit reels 26. The arms 28 may be movable between a loading/unloading
position in which new reels 26 may be rolled into position in the cradles 32
or in
which spent reels 26 may be rolled out of the cradles 32, and a use position
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(shown in Figures 1 and 2) in which the reels 26 are held above the ground and
are rotatable. Optionally, when the reels 26 are held in the use position they
are freely rotatable in the cradles 32. Alternatively, a tensioning means is
provided to maintain some selected tension in the conduit 12 and to inhibit
the
reels 26 from releasing more than a selected amount of conduit 12. In
embodiments configured for laying high-voltage electrical conduit 12, it may
be
advantageous to omit a tensioning means so that the tensile stress on the
electrical conduit 12 is reduced.
[0021] The trench former 18 is configured to form the trench 11 as the
vehicle 24 moves forward. The trench former 18 may have any suitable
structure for forming the trench 11. For example, referring to Figure 3, the
trench former 18 may be configured as a plow and may include a body 36
having a front face 38 covered with a plurality of plowing elements 40. The
plowing elements 40 may be generally C-shaped, having generally front faces
shown at 42, which are flat in a lateral direction, and generally planar side
faces
44, and having relatively sharp lateral corner edges 46 at the junctions of
the
front faces 42 and the side faces 44 respectively. During operation, as the
vehicle 24 moves forward, the plowing elements 40 continuously raise earth
upwards out of the trench 11. The plowing elements 40 may be removably
mounted to the trench former body 36, and may thus be made from a material
that is different from that of the trench former body 36 and that is selected
for
reduced wear during use. Additionally, by making the plowing elements 40
removable from the trench former body 36, the plowing elements 40 may be
easily replaced when they are excessively worn. The trench former body 36
may be slidably mounted on a trench former base 52 and may be vertically
adjustable with respect to the trench former base 52 by any suitable means,
such as by a trench former height adjustment hydraulic cylinder 54. The trench
former height adjustment hydraulic cylinder 54 may be used to control the
depth of the trench 11 that is formed.
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[0022] A separate vibratory mechanism 55 (Figure 3) may be provided
with the trench former 18 to assist in loosening earth in front of the trench
former 18. The vibratory mechanism 55 may have any suitable structure.
Alternatively, depending on the type of trench former that is used, vibration
may
inherently be produced. For example, certain types of trench former inherently
produce some vibration during use and as such can be considered to include a
vibratory mechanism. Some effects of such vibration are discussed further
below.
[0023] The trench former 18 may be connected to the vehicle 24 in any
suitable way. For example, a connecting arm 56 may have a first pivot
connection 58 to the rear of the vehicle 24 about a vertical axis, and a
second
pivot connection 60 to the trench former base 52 about a vertical axis. The
pivot connections 58 and 60 facilitate the vehicle 24 turning while the trench
former 18 is in the ground. It is alternatively possible to eliminate the
connection arm 56 and to provide a single pivot connection between the vehicle
24 and the trench former 18, however. By providing the connecting arm 56
with pivot connections 58 and 60 to the vehicle 24 and trench former 18, a
greater degree of flexibility is provided for the movement of the vehicle 24
with
respect to the trench former 18, relative to an embodiment with a single pivot
connection and no connecting arm. First and second pivot angle adjustment
hydraulic cylinders 62 and 64 may be provided at the first and second pivot
connections 58 and 60 for actively controlling the angles of the pivot
connections 58 and 60.
[0024] The base material handling system 20 is positioned rearwardly of
the trench former 18 and may be pivotally connected to the rear of the trench
former 18 at a third pivotal connection 66 about a vertical axis. Referring to
Figure 4, the base material handling system 20 includes a base material
hopper 67, a first base material passage 68 and a second base material
passage 69. The base material hopper 67 has an inlet 70 at the top. The base
material 14 may be fed into the base material hopper 67 by any suitable
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means. For example, in the embodiment shown in Figure 1, wherein the base
material 14 is sand, a sand storage and feed vehicle 72 (Figure 5) may travel
behind the base material hopper 67 and may feed sand into the base material
hopper inlet 70 via a belt conveyor or the like. A coarse grating 73 may be
provided at the base material hopper inlet 70, which assists in breaking up
large agglomerations of base material, and which also braces and strengthens
the base material hopper 67 in the region of the hopper inlet 70.
[0025] Referring to Figure 6, the base material hopper 67 has a first
hopper outlet 74 that feeds base material 14 into the first base material
passage 68 (Figure 4), which discharges base material into the trench 11 at a
first base material passage outlet 78. The base material hopper 67 also has a
second hopper outlet 80 that feeds base material 14 into the second base
material passage 69 which discharges base material into the trench 11 at a
second base material passage outlet 82.
[0026] The conduit feed system 22 includes a conduit feed passage 84
that extends from a conduit feed passage inlet 86 to a conduit feed passage
outlet 88. The conduit feed passage outlet 88 is positioned between the first
base material passage outlet 78 and the second base material passage outlet
82 in the sense that the conduits 12 are deposited in the trench 11 above the
base material 14 discharged from the first base material passage outlet 78 and
base material 14 is discharged from the second base material passage outlet
82 above the conduits 12 in the trench 11.
[0027] The conduit feed passage 84 may extend down through the base
material hopper 67 and between the first and second base material passages
68 and 69. Alternatively the conduit feed passage 84 may have another routing
whereby it extends downwards outside of the base material hopper 67 such
that the conduit feed passage outlet 88 still terminates between the first and
second base material passages 68 and 69.
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[0028] A plurality of rollers 90 are positioned in the conduit feed passage
84 to facilitate transport of the conduits 12 through the conduit feed passage
84. For the specific embodiment shown in the figures to be laying three phase
electrical conduits 12, the rollers 90 may be provided with a peripheral
profile,
shown at 92 (Figure 7), that is configured to hold the conduits 12 in a
triangular
arrangement.
[0029] The conduit feed passage inlet 86 is positioned to receive the
conduits 12 from the conduit reels 26. The conduit feed system 22 may further
include a conduit guide 94 (Figure 5) provided above the conduit feed passage
inlet 86 to guide the conduits 12 from the conduit reels 26 over the vehicle
cab,
shown at 96 (Figure 1), and downwardly into the conduit feed passage inlet 86.
[0030] The first base material passage 68 may extend generally
downwards (not necessarily strictly vertically downwards) from the first
hopper
outlet 74 to the first base material passage outlet 78. An air passage 97 may
be
provided in the wall 99 of the base material hopper 67 in the vicinity of the
first
hopper outlet 74. The air passage 97 inhibits bridging of the base material 14
as it passes through the first hopper outlet 74. The air passage 97 may be
configured in any suitable way. In the embodiment shown in Figure 9, the air
passage 97 is configured as a vertical slit 97a that extends above and below
the first hopper outlet 74 in combination with a horizontal passage 97b along
a
cross-sectional edge of the first hopper outlet 74.
[0031] Referring to Figure 8, the first base material passage 68 may be
generally rectangular in cross-section, and may be defined by a first side
wall
98, a second side wall 100, a front wall 102 and a rear wall 104. The spacing
between the first and second side walls 98 and 100 is shown at Dl and may be
defined as the spacing of the first base material passage 68 in a lateral
direction, ie. a direction that is perpendicular to the direction of travel of
the
base material handling system 20. The spacing Dl increases progressively in
a downward direction. Additionally, the spacing Dl between the first and
second side walls 98 and 100 may increase progressively in the rearward
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direction. The spacing between the front and rear walls 102 and 104 is shown
at D2 and may be defined as the spacing of the first base material passage in
a
longitudinal direction, ie. a direction that is parallel to the direction of
travel of
the base material handling system 20. The spacing D2 may increase in the
downward direction. By configuring the first base material passage 68 such
that the spacing Dl increases in the downward and rearward directions and
such that the spacing D2 increases in the downward direction, the first base
material passage 68 is configured to inhibit bridging of the base material 14
therein. The rates of increase of the spacings Dl and D2 may be selected
based on the particular properties of the base material 14. For some base
materials, for example, such as certain types of sand, the spacing Dl may
increase from about 5 inches at the top of the first base material passage 68,
shown at 106 (Figure 4), which is also the first hopper outlet 74, to about 5
1/4
inches at the bottom of the first base material passage 68, shown at 108,
which
is at the first base material passage outlet 78. Additionally, the spacing Dl
(Figure 8) may increase from about 5 inches at the front of the first base
material passage 68, shown at 110, to about 5 1/4 inches at the rear of the
first
base material passage 68, which is shown at 112.
[0032] To achieve satisfactory flow of base material 14 in the first base
material passage 68 it is particularly preferable for the first base material
passage 68 to be provided with all three of the aforementioned features,
namely that the spacing Dl increases in the downward direction; that the
spacing Dl increases in the rearward direction; and that the spacing D2
increases in the downward direction. It is, however, alternatively possible
that
satisfactory flow of base material 14 can be achieved with only one or two of
the aforementioned features being provided.
[0033] It will be noted that increasing one of the aforementioned
spacings Dl and D2 as noted above does not necessarily mean that the cross-
sectional area of the first base material passage 68 increases in the downward
direction. It will also be noted that the first base material passage 68 need
not
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be generally rectangular and may instead have any other suitable cross-
sectional shape for transporting base material 14. For example, the first base
material passage 68 may have one or more chamfered corners (as shown in
Figure 6). As another example, the first base material passage 68 may have a
generally rounded cross-sectional shape, such as a circular cross-sectional
shape, an elliptical cross-sectional shape, or an oval cross-sectional shape
or
an irregular cross-sectional shape. It is further possible for the first base
material passage 68 to have a cross-sectional shape that changes along the
length of the passage 68.
[0034] Without specific reference to any spacings (eg. Dl or D2), it is
possible to achieve satisfactory flow of base material 14 by configuring the
first
base material passage 68 to have a cross-sectional area that increases
progressively in a downward direction (see Figure 4).
[0035] The second base material passage 69 may be similar to the first
base material passage 68. For example, referring to Figure 4, the second base
material passage 69 may extend generally downwards (not necessarily strictly
vertically downwards) from the second hopper outlet 80 to the second base
material passage outlet 82. Referring to Figure 8, the second base material
passage 69 may be defined by a first side wall 114, a second side wall 116,
with a lateral spacing D3 therebetween, and a front wall 118 and a rear wall
120, with a longitudinal spacing D4 therebetween. The second base material
passage 69 may be configured such that the spacings D3 and D4 increase
progressively in a downward direction from the top of the second base material
passage 69, shown at 122 (Figure 4), to the bottom of the second base
material passage 69, shown at 124, and additionally such that the spacing D3
increases progressively in a rearward direction from the front of the second
base material passage 69, shown at 126, to the rear of the second base
material passage 69, shown at 128. By configuring the second base material
passage 69 such that the spacing D3 (Figure 6) increases in the downward and
rearward directions and such that the spacing D4 increases in the downward
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direction, the second base material passage 69 is configured to inhibit
bridging
of the base material 14 therein. As with the spacings Dl and D2, the rates of
increase of the spacings D3 and D4 may be selected based on the particular
properties of the base material 14. Also as with the spacings Dl and D2, it is
possible that satisfactory flow of base material 14 can be achieved by
providing
one or two of the three aforementioned features, though it is particularly
preferable for the second base material passage 69 to be provided with all
three of the aforementioned features.
[0036] It will be noted that increasing one of the aforementioned
spacings D3 and D4 in the downward direction does not necessarily mean that
the cross-sectional area of the second base material passage 69 increases in
the downward direction. It will also be noted that decreasing one of the
aforementioned spacings D3 or D4 does not imply that the overall cross-
sectional area of the second base material passage 69 is decreasing. In
particular, it can be observed in Figure 4 that along a lower portion of the
second base material passage 69, the longitudinal spacing D4 decreases,
while the lateral spacing D3 increases. The cross-sectional area of the second
base material passage 69 may or may not increase in this region, depending
on specific values for the spacings D3 and D4.
[0037] It will further be noted that, for the second base material passage
69, the spacing D3 (ie. the lateral spacing) is smaller than the spacing D4
(the
longitudinal spacing). By increasing the smaller spacing (in this particular
case,
the lateral spacing), satisfactory flow of base material 14 may be achieved
even
when the other spacing (in this case the longitudinal spacing) decreases along
a portion of the length of the passage 69.
[0038] As noted for the first base material passage 68, the second base
material passage 69 need not have a generally rectangular cross-section and
may instead have any suitable cross-sectional shape for transporting base
material. It is further possible for the second base material passage 69 to
have
a cross-sectional shape that changes along the length of the passage 69.
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[0039] Without specific reference to any spacings (eg. D3 or D4), it is
possible to achieve satisfactory flow of base material 14 by configuring the
second base material passage 69 to have a cross-sectional area that increases
progressively in a downward direction.
[0040] It will be noted that the vibration that occurs during use of the
trench former 18 (Figure 1) may pass into the base material 14 that is held in
the base material hopper 67 and in the first and second base material
passages 68 and 69 (Figure 4). With certain types of base material 14, the
induced vibration may urge the base material 14 to pack, which would
encourage bridging. Because of the induced vibration, it is particularly
advantageous to increase the cross-sectional areas of the first and second
base material passages 68 and 69 in the downward direction and/or to increase
the spacings Dl and/or D2 and D3 and/or D4 in the downward direction as
described above.
[0041] As the vehicle 24 moves forward, base material 14 is discharged
from the first base material passage 68 onto the floor of the trench 11. The
thickness of the layer of base material 14 that is discharged from the first
base
material passage 68 is determined by the height of the bottom edge, shown at
130, of the rear wall 104. The conduits 12 are laid on top of the layer of
base
material 14 discharged from the first base material passage 68. Base material
14 is discharged from the second base material passage 69 on top of and
around the conduits 12, preferably such that the base material 14 surrounds
the conduits 12 in the trench 11. The thickness of the layer of base material
14
that is discharged from the second base material passage outlet 82 is
controlled by the height of the bottom edge, shown at 132, of an outlet panel
134 that makes up a bottom portion of the rear wall 128 of the second base
material passage 69. The outlet panel 134 may be vertically movable so that
the height of the bottom edge 132 can be selected, so that the thickness of
the
layer of base material 14 discharged from the second base material passage
69 may be selected.
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[0042] To assist in protecting the conduits 12 from inadvertent damage
from work being carried out by workers afterwards, a cover layer 136 may be
provided from a cover layer reel (not shown) and may be fed through a cover
layer passage 138 and discharged on top of the conduits 12. The cover layer
passage 138 may extend adjacent the conduit feed passage 84. The cover
layer 136 may be made from a relatively tough material that is resistant to
puncture from construction equipment such as the bucket from a backhoe
loader. Thus, in the event that a worker inadvertently encounters the cover
layer 136 later on while digging, the cover layer 136 will resist puncture and
will
thus provide some protection to the conduits 12 lying underneath, inhibiting
damage to them from the worker's construction equipment.
[0043] Additionally, or alternatively, the system 10 may further include a
marker tape reel support 140 that holds a reel 141 of marker tape 142 and a
marker tape passage 144 that carries the marker tape 142 to a marker tape
passage outlet 146. The marker tape passage 144 may be connected to the
outlet panel 134 so that the marker tape passage outlet 146 is always a
selected distance above the bottom edge 132 of the outlet panel 134. In this
way, the marker tape 146 is always laid down in a consistent manner on top of
the base material 14 that is discharged from the second base material passage
69. As an alternative however, it is possible for the marker tape passage 144
to be connected to a non-moving member, such as a non-moving portion of the
rear wall 128. It will be understood that in such an alternative embodiment,
the
distance between the marker tape passage outlet 146 and the top of the base
material 14 would vary depending on the particular position of the outlet
panel
134.
[0044] It is conceivable that a customer may wish to use an existing
vehicle 24 and conduit reel support 16 (if one is required for the particular
application) instead of purchasing those components as part of the system 10.
Accordingly, it is possible that a supplier may supply an assembly that is
made
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up of only the trench former 18, the base material handling system 20 and the
conduit feed system 22 instead of supplying the entire system 10.
[0045] While the above description constitutes a plurality of
embodiments of the present invention, it will be appreciated that the present
invention is susceptible to further modification and change without departing
from the fair meaning of the accompanying claims.
