Note: Descriptions are shown in the official language in which they were submitted.
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A PORTABLE DEVICE FOR STORING AN ENDLESS
METALLIC OR FIBER-OPTIC CABLE
Background of the Invention
1. Field of the Invention. This invention
pertains to cable handling, and more particularly to
apparatus for laying underground cable.
2. Description of the Prior Art. The
contribution of fiber-optics to the communications age
is well known. With fiber-optics, thousands of
messages can be transmitted simultaneously through a
single fiber.
A major problem associated with fiber-optic
technology concerns the placement and protection of the
fiber-optic cables. It is generally accepted practice
to lay fiber-optic cables underground below the frost
line. Various equipment has been developed to
efficiently lay the cable across fields and other
unobstructed areas. However, substantial difficulties
are encountered when the fiber-optic cable must be laid
under such obstructions as highways, railroads, and gas
and oil pipelines. Splicing fiber-optic cables is both
costly and detrimental to the strength and quality of
the light signals to be pulsed through the cables.
To lay splice-free cables under various
obstructions, it is known to unwind an entire supply
reel of cable at the obstruction. The cable is pulled
back and strung in one or more long loops stretching
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away from the obstruction. The cable free end is then
fed through a bore under the obstruction. Finally, the
cable is rewound on the supply reel located on the
downstream side of the obstruction. A variation of the
pull-back method is the Figure 8 method. The cable is
entirely unwound from the supply reel, but it is laid
in the form of several overlapping figure-8s on the
ground. Both the pull-back and figure-8 methods are
very time consuming and therefore costly ways of
passing cables under obstructions. Further, laying the
fiber-optic cables on the ground renders them
susceptible to damage by machinery and personnel in the
area.
Manitou Industries of Neilburg, Saskatchewan,
Canada has developed apparatus that eliminates the need
for laying the cable on the ground at an obstruction.
The Manitou device employs a pair of special cable
reels that give access to the cable free end underlying
the overlying cable. At an obstruction, the plow
supply reel is unloaded from the plow and placed on the
ground. The cable free end is pulled from the special
reel and is partially unwound by an unwinding tower
attached to the reel. The cable free end is passed
under the obstruction. The cable free end is then
wound onto a second special reel on a trailer located
on the downstream side of the obstruction
simultaneously with unwinding the cable from the
original supply reel attached to the unwinding towel.
The second reel is then unloaded from the trailer and
loaded onto the plow, where it becomes the plow supply
reel for supplying cable until the next obstruction is
reached. At the next obstruction, the reel unloading,
unwinding, rewinding, and reloading process is
repeated. Although the Manitou system is an
improvement over merely laying the cable on the ground,
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it nevertheless requires substantial time to unload
and load two reels at the obstructions. further, a
substantial expenditure is required for the special
reels and the machinery for handling them.
Thus, a need exists for improved apparatus
and methods for laying continuous underground ca-
bles.
Summary of the Invention
In accordance with the present invention,
portable storage equipment is provided that effi-
ciently handles endless metallic of fiber-optic un-
derground cable at various obstructions in the cable
path. This is accomplished by apparatus that in-
cludes a rotatable drum and bail that temporarily
wind the cable onto an adjacent storage reel without
requiring access to either end of the cable.
The present invention provides a method of
placing a flexible cable beneath a surface obstruc-
tion that includes the steps of laying the cable in
a trench to a point adjacent the surface obstruc-
tion,
placing the unlaid cable onto a reel by
maintaining a portion of the cable in a predeter-
mined position adjacent a surface of the reel with-
out access to either end of the cable, and winding
the cable onto the reel commencing with the portion
of the cable maintained in a predetermined position
adjacent the reel to gain access to the end-to-end
of the cable;
feeding the end of the cable below the
surface obstruction; and
unwinding the cable from the reel by pull-
ing the cable from the end of the cable fed below
the surface obstruction.
In more general terms, the method of the
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invention can be described as including the steps of
laying the cable in a trench to a point
adjacent to surface obstruction; placing the unlaid
cable onto a reel by maintaining a portion of the
cable in a predetermined position adjacent to sur-
face of the reel without access to either end of the
cable, and winding the cable onto the reel commenc-
ing with the portion of the cable maintained in a
predetermined position adjacent the reel, to gain
access to an end of the cable; feeding the end of
the cable below the surface obstruction; and
unwinding the cable from the reel.
The invention also provides apparatus for
temporarily storing an elongated flexible cable that
includes: a frame; elongated support means mounted
on the frame for receiving a portion of the cable
therein along substantially the full length of the
support means
stationary reel means surrounding and per-
manently fixed to a first portion of the support
means for receiving a portion of the cable interme-
diate the cable ends; drum means rotatably mounted
to a second portion of the support means adjacent to
support means first portion and adjacent the reel
means for receiving a portion of the cable therein
and for winding the cable onto the reel means; and
guide means attached to the drum means for guiding
the cable onto the reel means.
In accordance with the further aspect of
the invention, guide means are provided in conjunc-
tion with the reel that entails the use of a drum
rotatably mounted to the support means adjacent the
reel in which the guide means includes an elongated
arm attached to the drum in extending over the reel;
a bail mounted to the arm free end and
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adapted to transversely receive the cable; and
a plurality of block means connected to
and located axially of the drum for cooperating with
the bail to form a smooth three dimensional path for
the cable as it is wound onto the reel when the drum
rotates.
Other objects, aims, and advantages of the
invention will become apparent to those skilled in
the art upon reading the disclosure.
Brief Description of the Drawinqs
FIG. 1 is a side view showing the portable
storage apparatus of the present invention in opera-
tion with a cable laying plow.
FIG. 2 is an enlarged top view of the por-
table storage apparatus of the present invention.
FIG. 3 is a cross-sectional view taken
along lines 3-3 of FIG. 2.
FIG. 4 is an enlarged partially broken
side view of the portable storage apparatus of the
present
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invention.
FIG. 5 is a cross-sectional view taken along
lines 5-5 of FIG. 4.
FIG. 6 is a view taken along lines 6-6 of
FIG. 4.
FIG. 7 is a view taken along lines 7-7 of
FIG. 4.
FIG. 8 is an enlarged cross-sectional view
taken along lines 8-8 of FIG. 4.
FIG. 9 is a side view of the inner tube of
the portable storage apparatus of the present
invention.
FIG. 10 is a cross-sectional view taken along
lines 10-10 of FIG. 9.
FIG. 11 is a cross-sectional view taken along
lines 11-11 of FIG. 9.
FIG. 12 is an enlarged front view of a snatch
block used on the portable storage apparatus of the
present invention.
FIG. 13 is a cross-sectional view taken along
lines 13-13 of FIG. 12.
FIG. 14 is a side view of the portable
storage apparatus and plow in the position for
rewinding the cable onto the plow supply reel.
FIG. 15 is a schematic diagram of the
hydraulic circuit of the present invention.
Detailed Description of the Invention
Although the disclosure hereof is detailed
and exact to enable those skilled in the art to
practice the invention, the physical embodiments herein
disclosed merely exemplify the invention which may be
embodied in other specific structure. The scope of the
invention is defined in the claims appended hereto.
Referring to FIG. 1, a portable storage
apparatus 1 is illustrated that includes the present
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invention. The storage apparatus is particularly
useful for cooperating with a conventional plow 3 for
laying underground flexible cable 5, but it will be
understood that the invention is not limited to cable
laying applications.
In the normal operation, the plow 3 comprises
a tractor 7 designed for off-road use over ground
surface 9. The tractor supports a supply reel 11 that
holds as much as 19,000 feet of fiber-optic or other
endless cable 5. The tractor is further equipped with
a conventional earth trenching device, schematically
represented at 13, as is known in the art. The
trencher 13 opens a trench 15 in the earth and may also
be designed to fill the trench. The tractor 7 includes
suitable means 17 for guiding the cable in long smooth
arcs from the reel 11 into the trench 15.
In accordance with the present invention, the
portable storage apparatus 1 is used to assist the
cable laying plow 3 to lay the cable 5 under horizontal
obstructions in the path of the cable route. Typical
obstructions encountered in cable laying operations
include railroad tracks, highways, and natural gas and
oil pipelines. In FIG. 1, an obstruction in the form
of a road 19 is illustrated.
Description of the Apparatus
The cable storage apparatus 1 comprises a
trailer 21 having a flat horizontal frame 23 supported
on conventional wheels and axles 25. The trailer 21
includes a tongue 27 equipped with a hitch 29 for
towing the apparatus by a conventional vehicle, such as
a pick-up truck, not shown.
Mounted to the trailer frame 23 is a large
cylindrical drum 31. The drum 31 is mounted for
rotation about its longitudinal axis 33 by mechanisms
to be described presently. Referring also to FIGS. 3-
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7, a radial slot 38 is formed in the drum. The slot 38
extends for the entire length of the drum.
The drum 31 is partially supported by rollers
37 that are rotatably mounted on the trailer frame 23
by suitable brackets 39. The rollers 37 may be rubber
tires. To rotate the rollers, orbital hydraulic motors
40 are fastened to the brackets 39, and the motor
shafts are coupled to the respective rollers.
The drum 31 is further supported by a long
center tube 41 that extends through the center of the
drum concentric with the drum axis 33 and that projects
out both drum ends. The center tube 41 is manufactured
with a long slot 42 that extends from the tube front
end 43 to a location beyond the drum back end 44. The
tube front end 43 is mounted in a stationary manner by
a support 45 firmly fixed to the trailer frame 23. In
the illustrated construction, the support 45 comprises
two pairs of braces 49 joined at their upper ends to
housings 46. The center tube passes through and is
welded to the housings 46. For additional rigidity, a
pair of plates 51 are welded to the braces 49, and
another plate 52 is welded to the housings 46. The
drum rotates about axis 33 on the tube 41 by means of
bearings 47, as is best shown in FIG. 3. The bearings
47 have radial slots aligned with the drum slot 38.
The housings 46 are formed with radial slots 48 FIG. 6,
that are aligned with the slots 42 in the center tube
41.
In addition to rotating about its
longitudinal axis 33, the drum 31 also reciprocates
therealong. For that purpose, the drum front end
includes a flange 53 that is captured by a gripping
mechanism 54. Looking also at FIGS. 2 and 8, the
gripping mechanism 54 comprises two pairs of flat
rollers 55. The flange 53 is gripped between each
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rollers 55, which are mounted on short shafts to the
top side of a plate 57. To the underside of the plate
57 are mounted two pairs of grooved rollers 59. The
flat rollers 55 and plate 57 are located on a
longitudinally extending guide plate 61 having tapered
edges by the grooves in the rollers 59. The ends of
the guide plate 61 are supported on the trailer frame
23 by suitable brackets 63. To reciprocate the drum, a
lead screw 65 mates with a nut 67 fixed to a horseshoe
69. The ends of the horseshoe 69 straddle the guide
plate 61 and are bolted to the plate 57. To rotate the
screw 65 and thus translate the drum, the screw is
connected by suitable drive means 71 to a hydraulic
motor 73. The drum reciprocates between the position
shown in the solid lines of the drawings and a position
wherein the drum front flange 53 is in the general
location shown by the phantom lines 53'.
Mounted to the back end 75 of the center tube
41 is a stationary hollow reel 77. The reel 77 may be
held in place on the center tube by a handled nut 79
threaded onto the center tube end 75. To permit
different sized reels to be mounted on the center tube,
a spacer 81 may be interposed between the nut 79 and
the reel. The reel is formed with a radial slot 78
that extends through the reel core 80 and the front
flange 82. A slotted tube 84 is fixed
circumferentially around the inner diameter of the reel
core 80 at the back end thereof. The slotted tube 84
extends approximately three-fourths of the way around
the inner diameter of the reel core as is best shown in
FIG. 7.
Extending through generally the entire length
of the center tube 4 is an inner tube 83. The inner
tube 83 is loosely contained within the center tube,
such that it may be freely turned within the center
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tube. The inner tube is preferably made from a
synthetic plastic material, such as polyvinylchloride.
Turning to FIGS. 9-11, the inner tube is fabricated
within a slot 85 that starts at the front end 86 and
extends almost the entire length of the inner tube and
that passes completely through the tube wall. The slot
85 is generally parallel to the longitudinal axis for
the major portion of the inner tube length. However,
near the back end 87 of the inner tube, the slot 85
deviates in an angular manner for a short distance at
locations 89. A short offset section of longitudinal
slot 85' joins the two angular sections 89, thereby
forming a lip 88 of material. The slot 85 terminates
at a location 9G that is between the flanges of the
reel 77 when the inner tube is inserted into the center
tube. Preferably, the slot end location 96 is close to
the reel front flange 82. To facilitate locating and
turning the inner tube within the center tube, the
inner tube front end is formed with a flared portion
91.
Attached to the periphery of the drum 31 is
an arm 35 that extends longitudinally over the back end
44 of the drum, as best seen in FIGS. 2 and 7. To the
free end of the arm 35 is fastened a hook-like bail 36.
Also extending longitudinally from the back
end 44 of the drum 31 are a series of stiff strips.
Five strips 93a-93e are illustrated in FIGS. 1, 2, 4,
and 7, but it will be appreciated that more or fewer
strips may be employed. The strips 93 are spaced
circumferentially around a portion of the drum
periphery. The strips are of unequal length, with one
end strip 93a being the longest, and the opposite end
strip 93e being the shortest. The shortest strip 93e
terminates forward of the back flange 95 of the reel 77
when the drum is in the backmost position, i.e., when
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the drum is in the position in the solid lines of the
drawings. To increase the rigidity of the strips,
their free ends may be connected together with cross
strips, such as strip 92 between strips 93b and 93c in
FlG. 2. For clarity, the other stiffening strips are
not shown in the drawings.
Attached to the free end of each strip 93a-
93e by any suitable means, such as a plate 94, is a
respective snatch block 97a-97e. With particular
attention to FIGS. 12 and 13, the snatch blocks 97 may
be composed of two symmetrical halves 99 pivotally
joined by a spring loaded hinge 101 that is biased to
the closed position of the drawings. The openings 103
through the halves 99 are smoothly radiused, as at 105,
at their junctions with the half faces. Preferably,
the snatch blocks are made of a non-metallic material.
Turning back to FIGS. 1-7, the plates 94 are
welded to the strips 93 at appropriate angles thereto,
such that the snatch block openings 103 define a smooth
continuous path in three dimensions. The path begins
at snatch block 97a. The axis of opening 103 of the
end snatch block 97a is approximately parallel to the
drum axis 33. The path ends at snatch block 97e. The
axis of the opening of the snatch block 97e is
approximately perpendicular to the drum axis and is
generally aligned with the opening in the hooked bail
36. The openings of the intermediate snatch blocks
97b-97d are arranged to provide a smooth transition
between the two end snatch block openings.
In FIGS. 1 and 2, reference numerals 107
represents posts upstandingly fixed to the trailer
frame 23. Additional similar posts are fixed to the
frame along the two sides thereof, but for clarity they
are not shown. The posts 107 are used to hold expanded
metal or similar guarding material. Pivotally
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connected to the posts at the back end of the trailer
21 are a pair of gates 109. The pivotal connection may
be by conventional hinges 111. The gates 109 have
frames made of square tubing or angle iron. Expanded
metal guarding spans the opening areas between the gate
frames. Pivotally connected, as by hinges 113, to the
free ends of the gates 109 are respective second gates
115. During transportation of the portable storage
apparatus, the gates 109 and 115 are folded to a closed
inoperative configuration against the back end of the
trailer, as shown by the phantom lines 109' and 115'.
Mounted to the free end of each gate 115 is
one half 117 of a double flared guide funnel 119. The
funnel halves 117 have flared inner diameters 121.
Mounting of the guide halves to the gates may be by
plates 123. As best seen in FIG. 2, the two guide
halves are matable to form the enclosed guide 119 when
the gates 109 and 115 are in the unfolded operative
configuration. A conventional latch is employed to
retain the free ends of the gates 115 together and
thereby hold the two guide funnel halves in place.
In the preferred embodiment, the portable
storage apparatus 1 of the present invention includes a
hydraulic system for rotating and reciprocating the
drum 31. The hydraulic system is powered by a
conventional internal combustion engine located under
the support 45 and schematically represented as
reference numeral 123 in FIG. 6. The engine 123 drives
a conventional hydraulic pump, which forms part of a
hydraulic power unit 125, as is known in the art.
Suitable hydraulic lines lead from the hydraulic power
unit 125 to the hydraulic motors 40 and 73.
FIG. 15 shows a schematic diagram of the
hydraulic circuitry associated with the portable
storage apparatus 1 of the present invention. The
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circuitry includes a hydraulic pump 127 driven by the
internal combustion engine 123 and supplied with
hydraulic fluid from a reservoir 129. Hydraulic fluid
under pressure is pumped to hydraulic motor 73 for
reciprocating the drum 31 and to hydraulic motors 40
for rotating the drum. Directional control valves 131
and 133 are used to reverse the direction of rotation
and reciprocation, respectively. Valves 135 and 137
assure proper synchronization between drum rotation and
reciprocation.
Operation
Returning to FIG. 1, the plow 3 moves from
left to right. It will be assumed that the plow has
laid a length of fiber-optic or other flexible cable 5
from the supply reel 11 in the trench 15. For the
normal cable laying operation, the trencher 13 is in an
operative position such that it engages the earth to
dig the trench, and the cable is laid on the trench
bottom 139. It will further be assumed that an
obstacle in the form of a road or highway 19 lies in
the path of the cable. In accordance with the present
invention, the plow 3 retracts the trencher 13 to an
inoperative position, such as is shown in FIG. 1, when
the plow is approximately 50 feet from the road. The
plow continues to advance to the edge of the road,
laying the cable 5 on the surface 9 of the ground. A
few feet of slack are unwound from the supply reel.
The portable storage apparatus 1 of the
present invention is then towed to a location near the
plow 3. Preferably, the storage apparatus is parked
between the plow and the end of the trench 15, with the
drum axis 33 approximately parallel to the slack cable
on the ground. The drum 31 is rotated under hydraulic
power by the rollers 37 and motors 40 until the drum
slot 38 is in angular alignment with the slots 48 in
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the housings 46 and with the slot 42 in the center tube
41. The inner tube 83 is manually positioned such that
the slot 85 therein is aligned with the center tube and
drum slots. Referring also to FIGS. 2-7 and 10, the
slack cable 5 laying on the ground is then picked up,
starting at the trailer front end. The cable is fed
transversely through the slots 48 in the housings 46,
through the slot 42 in the front end 43 of the center
tube 41, and through the slot 85 in the inner tube,
such that the cable is supported inside the inner tube.
The cable, which has attained a position 5' at the
front end of the trailer 21, is further fed through the
slot 38 in the drum 31, and through the center tube and
inner tube slots in line with the drum slot, such that
the cable is supported in the inner tube from the front
end 86 thereof to the drum back end 44. The cable 5'
is inserted through the slot 78 in the reel front
flange 82 and the core 80. The cable is further pushed
through the center tube slot 42 and inner tube slot 85
underlying the reel core 80. The inner tubé is rotated
manually by means of the flared end 91 to enable the
cable to be inserted through the angular slots 89, and
the short offset slot 85' up to the slot end 96. The
lip 88 on the wall of the inner tube overlaps the
center tube slot 42 and thereby prevents the cable
inside the inner tube from escaping through the slots
85 and 42. With the cable inside the inner tube as far
as the slot end 96, additional cable is pushed through
the reel slot 78 to create a large loop 140 inside the
reel inner diameter 90. The cable loop 140 is guided
into the upper end 141 of the tube 84 fixed to the reel
inner diameter. The cable loop passes beyond the
retainer tube lower end 143. Because there is no slot
in the reel back flange 95, the cable remains
positioned permanently through the slot 78 near the
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back flange 95. The cable may be wrapped around the
reel core 80 and inserted transversely into the bail
36. From the bail, the cable is inserted transversely
into the snatch blocks 97, which are successively
opened to receive the cable and then closed by means of
the spring loaded hinges 101. Finally, the cable is
positioned within one of the guide funnel halves 117.
The gates 109 and 115 are positioned to bring the
funnel halves together to form the guide funnel 119,
with the cable captured therein. The gates are latched
in place.
The internal combustion engine 123 of the
portable storage apparatus 1 is then started to operate
the hydraulic power unit 125. In a first position, the
control valve 131 will cause the drum 31 to turn in the
direction of arrow 147 of FIG. 7, thereby winding the
cable 5' onto the reel 77 and unwinding the cable from
the plow supply reel 11. Simultaneously, control valve
133 causes the drum to reciprocate along axis 33 to
create neat layers of cable on the reel 77. The smooth
continuous path formed by the guide funnel 119, snatch
blocks 97, and bail 36 permit winding the cable without
damage. In that manner, the cable is windable onto the
storage apparatus of the present invention without
having access to either cable end.
Eventually, the entire cable 5 is unwound
from the plow supply reel 11 and wound onto the storage
reel 77. When that has occurred, the plow 3 is driven
across the road 19 at any safe and convenient location.
Meanwhile, the trench 15 is completed up to the road by
other known equipment.
Turning now to FIG. 14, the plow 3 is shown
in a new location across the road 19. A tunnel 149 is
bored under the road. The cable free end is threaded
through the bore 149 and reattached to the plow supply
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reel 11. The storage apparatus hydraulic circuitry is
operated to rotate the drum in the direction of arrow
151 in FIG. 7, thereby unwinding the cable from the
reel 77. At the same time, a suitable drive on the
plow operates to wind the cable back onto the supply
reel. When all the cable is unwound from the storage
reel 77, the cable is pulled transversely out of the
various slots 42, 38, 48, 85, 85', 89, and 78; bail 36;
snatch blocks 97; retainer tube 84; and guide funnel
119. The cable is laid within the trench 15 up to the
road and then wound by the plow supply reel to take up
the slack. The plow is then able to resume cable
laying operations in a normal manner. The trailer 21
is towed to the next road or other obstruction in the
cable path.
Thus, it is apparent that there has been
provided, in accordance with the invention, a portable
device for storing an endless metallic or fiber-optic
cable that fully satisfies the aims and advantage set
forth above. While the invention has been described in
conjunction with specific embodiments thereof, it is
evident that many alternatives, modifications, and
variations will be apparent to those skilled in the art
in light of the foregoing description. Accordingly, it
is intended to embrace all such alternatives,
modifications, and variations as fall within the spirit
and broad scope of the appended claims.
