U.S. patent application number 11/015206 was filed with the patent office on 2005-05-19 for process for introducing an optical cable into solid ground.
Invention is credited to Finzel, Lothar, Kossat, Rainer, Kunze, Dieter, Zeidler, Gunter.
Application Number | 20050105874 11/015206 |
Document ID | / |
Family ID | 27570765 |
Filed Date | 2005-05-19 |
United States Patent
Application |
20050105874 |
Kind Code |
A1 |
Finzel, Lothar ; et
al. |
May 19, 2005 |
Process for introducing an optical cable into solid ground
Abstract
The invention relates to a process for introducing an optical
cable, in the form of a microcable or minicable (1), in solid
ground (17) with the aid of a laying unit (23). The microcable or
minicable (1) used for this purpose comprises a homogeneous and
pressurized-water-tight tube (8) which has an external diameter of
from 2.0 to 10 mm and into which optical waveguides (3) are
introduced.
Inventors: |
Finzel, Lothar;
(Unterschleissheim, DE) ; Kunze, Dieter; (Neuried,
DE) ; Zeidler, Gunter; (Germering, DE) ;
Kossat, Rainer; (Aschau, DE) |
Correspondence
Address: |
CORNING CABLE SYSTEMS LLC
P O BOX 489
HICKORY
NC
28603
US
|
Family ID: |
27570765 |
Appl. No.: |
11/015206 |
Filed: |
December 17, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11015206 |
Dec 17, 2004 |
|
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10051597 |
Jan 18, 2002 |
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6866448 |
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Current U.S.
Class: |
385/135 |
Current CPC
Class: |
H02G 1/086 20130101;
G02B 6/4463 20130101; E02F 5/101 20130101; H02G 1/06 20130101; H02G
9/10 20130101; H02G 9/02 20130101; G02B 6/4459 20130101; G02B 6/504
20130101 |
Class at
Publication: |
385/135 |
International
Class: |
G02B 006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 1995 |
DE |
195 42 231.7 |
Mar 28, 1996 |
DE |
196 12 457.3 |
Apr 25, 1996 |
DE |
196 16 598.9 |
Apr 25, 1996 |
DE |
195 16 596.2 |
Apr 25, 1996 |
DE |
196 16 595.4 |
Jun 12, 1996 |
DE |
196 23 483.2 |
Aug 19, 1996 |
DE |
196 33 366.0 |
Sep 30, 1996 |
DE |
196 40 290.5 |
Claims
1-122. (canceled)
172. A fiber optic cable installation structure comprising: a
surface defining a channel having a width of about 12 mm or less; a
cable disposed within the channel, said cable having at least one
optical waveguide disposed within a copper tube and a jacket
surrounding the copper tube, wherein the copper tube has a ratio of
a wall thickness to an external diameter, the ratio being in the
range of about 0.2 to about 0.05; and a filling material overlying
the cable and at least partially filling the channel, the filling
material at least partially comprised of material not previously
evacuated to form the channel.
173. The fiber optic cable installation structure of claim 172,
wherein the cable has a diameter of about 10 mm or less.
174. The fiber optic cable installation structure of claim 172,
wherein the surface defines the channel to have a width of about 7
mm or less.
175. The fiber optic cable installation structure of claim 172,
wherein the cable has a diameter of about 5.5 mm or less.
176. The fiber optic cable installation structure of claim 172,
wherein the surface defines the channel to have a depth of about 15
cm or less.
177. The fiber optic cable installation structure of claim 172,
wherein the surface comprises a solid surface selected from the
group consisting of asphalt, concrete, road surface, curbstone, and
stone slab.
178. The fiber optic cable installation structure of claim 172,
further comprising a release element disposed within the channel
and extending lengthwise along the cable, the filling material also
overlying the release element.
179. The fiber optic cable installation structure of claim 172,
wherein the filling material is formed of a material selected from
the group consisting of bitumen and a hot melt adhesive.
180. The fiber optic cable installation structure of claim 172,
further comprising a hold-down device, the hold-down device
disposed within the channel for holding the cable within the
channel.
181. A fiber optic cable installation structure comprising: a
surface defining a channel; a cable disposed within the channel,
the cable comprising a copper tube and at least one optical
waveguide disposed within the tube; a hold-down device, the
hold-down device disposed within the channel for holding the cable
within the channel; and a filling material overlying the cable and
the hold-down device and at least partially filling the
channel.
182. The fiber optic cable installation of claim 181, the copper
tube having a ratio of a wall thickness to an external diameter,
the ratio being in the range of about 0.2 to about 0.05
183. The fiber optic cable installation structure of claim 181,
wherein the surface defines the channel to have a width of about 12
mm or less and the cable has a diameter of about 10 mm or less.
184. The fiber optic cable installation structure of claim 181,
wherein the surface defines the channel to have a width of about 7
mm or less and the cable has a diameter of about 5.5 mm or
less.
185. The fiber optic cable installation structure of claim 181,
wherein the surface defines the channel to have a depth of about 15
cm or less.
186. The fiber optic cable installation structure of claim 181,
wherein the surface comprises a solid surface selected from the
group consisting of asphalt, concrete, road surface, curbstone, and
stone slab.
187. The fiber optic cable installation structure of claim 181,
wherein the filling material is formed of a material selected from
the group consisting of bitumen and a hot melt adhesive.
188. A fiber optic installation structure comprising: an elongate
body defining at least one lengthwise extending copper duct
disposed within a channel defined by a solid surface, wherein the
channel has a depth of about 15 cm or less; at least one optical
waveguide disposed within at least one lengthwise extending copper
duct defined by the elongate body; and a filling material overlying
the elongate body and at least partially filling the channel.
189. The fiber optic installation structure of claim 161, wherein
the elongate body is sized to fit within the channel having a width
of about 12 mm or less.
190. The fiber optic installation structure of claim 161, wherein
the elongate body is sized to fit within the channel having a width
of about 7 mm or less.
191. The fiber optic cable installation structure of claim 161,
wherein the solid surface is selected from the group consisting of
asphalt, concrete, road surface, curbstone, and stone slab.
Description
[0001] The invention relates to a process for introducing an
optical cable, consisting of a tube and optical waveguides
introduced therein, into solid ground with the aid of a laying
unit.
[0002] DE-A1-41 15 907 discloses a cable-laying plough for laying
cables in the ground, in particular in the ground under water. In
this case, the blade of the cable-laying plough has arranged in
front of it a rotating cutting wheel which, in addition, is made to
vibrate vertically, with the result that hard objects located in
the region of the trench which is to be excavated may thus also be
broken up thereby. This cable-laying plough excavates relatively
wide trenches by displacing the soil with the aid of the plough
blade. Such machines are used, in particular, in coastal areas and
under water using corresponding control devices. For laying
operations in the ground, the material is usually removed over a
width of from 60 to 100 cm and a cable-laying depth of
approximately 70 cm, with the result that the outlay for the laying
operation is relatively high.
[0003] Furthermore, DE-A1-30 01 226 discloses a line network for
transmitting signals, the signals being passed through fibre-optic
cables which are laid in a network of pipes or ducts of an existing
supply system. In this case, however, fixed cable-laying routes are
predetermined, and inlets and outlets for the cable which is to be
laid have to be provided in a suitable manner therein.
[0004] Alternatively to this, use may also be made, over short
distances, of so-called drilling or jetting processes in which a
tube is introduced horizontally into the ground. The high outlay
for laying machines and material is also disadvantageous here.
[0005] JP-A-61 107 306 discloses an optical waveguide which is
provided with a metal tube in order to increase tensile strength.
The optical waveguide is provided with a sheath of vinyl, nylon or
urethane, these materials having elastic properties and thus
protecting the optical waveguide mechanically against external
influences. In order to increase the tensile strength, a metallic
tube is also applied, loosely at first. Then the tubes are
stretched and thus secured to the sheathed optical waveguide.
[0006] FR-A-2 677 137 discloses a repair method for optical cables
which are composed of a tube and optical waveguides running
therein. At the defective point, an adapted tubular element is
inserted, to which the ends of the defective tube are connected
again, the defective point being bypassed.
[0007] EP-A-0 553 1991-A discloses a repair method for conventional
optical cables, two cable sleeves being used in which the
connections are made between the optical waveguides by means of an
intermediate cable element.
[0008] The object of the present invention is to provide a process
for introducing an optical cable in which the outlay for the laying
operation can be reduced, it also being intended that the outlay
for the optical cable system used be coordinated with the laying
method. The set object is achieved according to the invention, by a
first process of the type explained in the introduction, in that
the optical cable used is a microcable or minicable having an
external diameter of the tube of 2.0 to 10 mm, preferably 3.5 to
5.5 mm, the tube being homogeneous and pressurized-water-tight, a
laying channel with a width of 4.5 to 12 mm, preferably 0.7 mm,
which is adapted to the diameter of the microcable or minicable,
being introduced with the laying unit into the solid underlying
laying surface, the microcable or micro[sic]cable being introduced
into the laying channel by means of a feed element and being held
at a constant laying depth, the laying channel being filled with
filling material using a filling device which is moved along after
the insertion of the microcable or minicable.
[0009] The object which has been set is thus achieved in accordance
with the invention planning to a second method of the type
mentioned at the beginning in such a way that a microcable or
minicable with an external diameter of the tube of 2.0 to 10 mm,
preferably 3.5 to 5.5 mm is pressed into utility lines for
sewerage, gas or water, which have been left open, using a laying
unit.
[0010] The object which has been set is achieved according to the
invention using a third method of the type mentioned at the
beginning in that the optical cable used is a microcable or
minicable with a diameter of the tube of 2.0 to 10 mm, preferably
3.5 to 5.5 mm, which is inserted into existing, active utility
lines for sewerage gas or water using a laying unit.
[0011] A great advantage of the process according to the invention
is that only a relatively short amount of time is taken for the
laying operation, with the result that it is used particularly
wherever long-term hold-ups are undesirable. This is the case, for
example particularly when laying new or additional cables, when the
laying operation has to be carried out in urban areas with heavy
traffic. Blocking off or diverting is to be avoided as far as
possible. The operations of cutting, laying and sealing the channel
can take place directly one after the other, these operations
expediently being carried out all in one go by a multipurpose
machine. In this manner, the traffic disruption is barely greater
than that caused by a road sweeper. There is also such a need, for
example, when all the laid pipes, cable ducts or pipelines have
already had cables laid in them, it then being possible to splice
onto the newly laid cables without interruption. Tubular mini
communication cables, which are referred to as microcables or
minicables, are particularly suitable for this purpose. These newly
laid minicables or microcables may preferably be connected to form
a redundant overlay network.
[0012] According to the invention, such a minicable or microcable
comprises a homogeneous and pressurized-water-tight tube of very
small diameter of from 2.0 to 10 mm, preferably 2.2 to 5.5 mm.
These tubes have a wall thickness of from 0.2 to 0.4 mm. The most
favourable values as regards the buckling resistance are achieved
with a wall thickness to an external diameter ratio of between 1/5
and 1/20, preferably approximately 1/10. The smallest internal
diameter of the tube used is 1.8 mm. This tube may be produced from
metal, for example from chromium-nickel-molybde- num (CrNiMo188)
steel, aluminium alloys, copper or copper alloys or from plastic,
for example with reinforcement inserts consisting of carbon fibres,
glass fibres, or a sintered carbon-fibre structure. These tubes may
be extruded, welded, folded or bonded longitudinally at the
overlap. The optical waveguides are then introduced into the tube
either after the empty tube has been laid or at the factory. The
optical waveguides can be blown in or jetted in.
[0013] The tubular minicable can be introduced into solid ground by
various types of process according to the invention:
[0014] 1. The laying may be carried out by means of a laying
machine which has a cutting wheel, with the aid of which a narrow
laying channel having a width of from 4 to 12 mm, preferably 7 mm,
and a depth of from 50 to 100 mm, preferably 70 mm, is cut in the
ground, in particular in an existing roadway.
[0015] 2 Such a minicable may also be forced into disused supply
lines (wastewater, gas, water). Disused pipelines of utility
companies are particularly suitable for a laying operation. They
correspond largely with the supply network planning to be set up.
Even if the disused pipes are in bad condition, it is possible to
introduce the thin metal tubes of the minicable since they are
pressed in in the longitudinal direction and pass through
obstructions such as dirt, rust and the like. The minicable does
not buckle in pipes since it is supported by the disused supply
line. After leaving these pipelines, the laying operation may also
be continued with the aid of other laying processes.
[0016] 3. It is likewise possible for a minicable to be pushed into
existing, active supply lines (wastewater, water). The function of
the supply lines is barely impaired to any extent at all in this
case. The tubular minicable is resistant to pressurized water,
wastewater and corrosion. Gnawing by rodents can be ruled out due
to the large wall thickness of the metal tube. It can be assumed
that the optical-waveguide network which is to be installed
corresponds with the existing supply network. Earthworks may thus
be reduced to a minimum. Appropriate fittings which make it
possible to lift the minicable out of the supply lines are to be
provided at the appropriate locations.
[0017] 4. Minicables may likewise be introduced into the ground by
earth-displacement or jetting processes. In this case, first of all
the tube of the minicable is introduced, as a mechanical
protection, into the ground. Expediently, the fibre conductors, or
very thin blown fibres, are subsequently blown or jetted in. In
order to minimize the friction during the blowing-in operation, the
tubes, which are produced without seams and are smooth on the
inside, are coated with a plastic layer, e.g. PTFE. This layer is,
for example, deposited from a PTFE suspension when the metal tube
is heated correspondingly. Moreover, this layer protects against
corrosion and soiling of the tube interior. Earth-displacement and
pressing-in operations in which a drilling head with a bevel
rotates constantly are known. If the drilling head does not rotate,
the drilling body is deflected in accordance with the bevel. It is
thus possible to bypass obstructions. A water jet at very high
pressure may, for example, force away small stones. The tube cuts
or jets its way through the ground and assists the advancement of
the pressing-in process. Moreover, the water pressure can move a
piston in the drilling body. The thrust-like movement of the
drilling head then breaks through obstructions more easily and
reduces the static friction during the drawing-in operation.
[0018] By elastic expansion of the tube, the wall friction with
respect to the earth can be reduced further. For this purpose, an
outlet valve would have to be provided at the end of the tube.
[0019] Using the tubular minicable according to the invention,
then, results in particular advantages, as follows. The laying or
introduction takes place with the aid of a hollow tube, which, as
cable, is already provided with optical waveguides; however, it is
also possible for the optical waveguides to be drawn in
subsequently. Appropriate selection of the wall thickness ensures
sufficient protection against mechanical loading, corrosion and
gnawing by rodents. Moreover, the tube has a high stability to
transverse compressive stress. For lengthening and thinning the
tube, use may be made of methods, which are known per se, with
cutting clamping rings or a crimping process. For lengthening a
tube consisting of copper, connection by cold pressure welding is
possible, for example. Otherwise, the tube can be processed like a
normal installation pipe, these methods relating to bending,
provision of fittings, branchings and inlets in sleeves. Also
suitable for this purpose are cylindrical metal fittings into which
the minicable can be introduced tightly. When the laying operation
is taking place from the surface of the ground, the surface is only
minimally broken up, which is particularly advantageous for laying
operations in roads. Moreover, as a result of the rigidity, pulling
and pushing the minicable is possible and helpful in the laying
operation. Due to the small diameter of such a minicable, the earth
displacement is also particularly low, it being possible for the
earth to be displaced when the cable is pressed or drawn into the
surrounding earth.
[0020] A tubular microcable or minicable is particularly suitable
for laying in a roadway or in footpaths since the roadway formation
is barely broken up by the necessary channel. All that is necessary
in order to ensure the safety of such a cable is a channel having a
width of 4 to 12 mm and a depth of approximately 70 mm. In this
case, the channels for receiving the cables should, as far as
possible, only be provided on the sides of the road since stressing
is at its lowest here. The channel which has been introduced is
refilled after the introduction of the cable or of the tube and is
sealed against the penetration of surface water. This sealing must
not produce any cavities in which surface water can collect. The
roadway surface can be restored in a simple manner. All that is
required during repair work is that, when the road surface is cut
away, the minicable or microcable which has already been laid is
not damaged.
[0021] A laying operation using a microcable and the corresponding
laying process according to the invention produces considerable
reductions in the costs for the laying method, this resulting in a
considerable reduction in the overall line-laying costs in the case
of a new installation. Moreover, the operational reliability is
increased by redundant routing.
[0022] It is also advantageous that annular network structures with
various connection possibilities can be formed from former rigid,
star-shaped branching networks. A flexible, intelligent network
design is obtained in this manner, it being possible for
microcables to be switched in with the aid of optical switches. A
pigtail ring with optical switching, in which optical fibres could
be routed as far as the subscriber, would thus be possible. It is
highly advantageous that subsequent laying operations in roads,
footpaths, cycle paths, curbstones and the like are possible with a
low degree of outlay. Consequently, a technical concept may be
adapted in a simple manner to the wishes of the operator, it being
possible to utilize the existing infrastructure (wayleaves, and
pipes for wastewater, gas, district heat, etc.) It should also be
noted here that, in comparison with the standard method, this
method can save a large amount of time.
[0023] Various points should be noted when a laying channel is
provided in an asphalt surface of a federal road which is made up
of a top surface course of 4 cm, a binder course of approximately 8
cm and a base course of from 10 to 15 cm. The proportion of bitumen
decreases towards the base course, but the coarse-grained fillers
increase. However, the bitumen ensures the cohesion within the
individual layers. During cutting as far as the asphalt base
course, the laying channel is, then, dimensionally stable, with the
result that no material caves in and the overall upper road
structure remains intact. During cutting, it is not permitted to
cut through the bitumen base course as far as the anti-frost layer
of the substructure since this may result in weak points in the
series of asphalt layers, which weak points could break up the
layer formation and result in damage to the road within a short
period of time. However, if the minicable is laid in a water-tight
and frost-resistant manner, the soil mechanics are not influenced
by this intervention. However, modern roads are frost-resistant
since the crushed-stone substructure bears and absorbs loads. This
discharges gravitational water into the earth or into drain pipes,
and a sealed, intact surface course does not let in any surface
water. Frost damage cannot therefore occur. This minimum
laying-channel width and vibration-free cutting means that the
mechanical structure of the road remains intact. Directly after the
laying operation, the laying channel is closed off again in a
frost-resistant manner by a hot-melting bitumen or by a fusible
preformed bitumen filler.
[0024] However, very heavy traffic may result in additional
consolidation and flow in the upper structure of the road (lane
grooves, shoulder). It is thus recommended that the laying channel
is foam-filled with a curable plastic around the minicable directly
after the latter has been laid. After curing, the foam filling
achieves a compressive stressability which is sufficient for
further distributing the load of the carriageway surface uniformly.
Cavities and interstices between the minicable and the laying
channel are filled, without leaving any cavities which could
receive any surface water which may penetrate and propagate this
surface water along the minicable.
[0025] Vibrations due to the heavy traffic are absorbed by the foam
filling and are not passed on to the minicable. Relatively small
occurrences of the earth subsiding may also be compensated for by
the elastic foam, with the result that such irregularities in the
bitumen base course would not result in the failure of the
minicable due to bending of the tube or fibre elongation.
[0026] For a minicable according to the invention, compressed-gas
monitoring and monitoring with a liquid, for example, are also
possible. The minicable may thus also be filled with a liquid
which, in the case of the tube having a defect, escapes and
resinifies under the action of air. This ensures a kind of
"self-healing".
[0027] Moreover, the minicable is interception-proof since the
optical waveguides cannot be bent. The minicable is stable with
respect to transverse forces, has a high tensile force, is compact
and, on account of the small diameter, has a relatively low weight
and little friction. The tube, which acts as the cable sheath, also
assumes, at the same time, the tensile-force function of the
otherwise customary central element in this high-strength cable
with very low expansion, there is no problem in respect of excess
lengths when the minicable is drawn in and laid. This configuration
gives a higher strength in comparison with a normal cable with a
conventional plastic cable sheath, with the result that it is also
possible to work with considerably larger drawing-in forces.
Moreover, straightforward earthing is possible in the case of the
metal embodiment. If use is made of a plurality of tubes which are
insulated with respect to one another, the metal cross-section may
also be used for supplying power to active components. By using
metal tubes, it would also be possible for overhead cables to be of
a considerably more straightforward construction. A supporting
element (e.g. a messenger wire) could then be dispensed with since
the metal tubes assume this function. In addition, such a minicable
is pressurized-water-tight, gas-tight, forms a water vapour barrier
and gives protection against the gnawing of rodents. Furthermore,
it is fire-resistant, has excellent heat-dissipation properties and
is resistant to aging and corrosion.
[0028] The flexibility of the minicable or of the tube can be
improved by a grooved sheath.
[0029] Further developments of the invention are given in
subclaims.
[0030] The invention will now be explained in more detail with
reference to 57 figures.
[0031] FIG. 1 shows a construction of the tubular microcable or
minicable with a capping.
[0032] FIG. 2 shows, schematically, a longitudinal section through
the minitube without optical waveguides.
[0033] FIG. 3 shows, schematically, the laying operation for a
minicable.
[0034] FIG. 4 shows the forcing-in process for a minicable.
[0035] FIG. 5 shows the pushing-in process for a minicable.
[0036] FIG. 6 shows the jetting process for a minitube.
[0037] FIG. 7 shows the method of laying the tubular minicable with
the laying channel already filled again.
[0038] FIG. 8 illustrates the cross-section of a road-surface with
a laying channel cut therein.
[0039] FIG. 9 shows the laying channel which has already been
filled in.
[0040] FIG. 10 shows a U-shaped holding-down device for microcables
in the laying channel.
[0041] FIG. 11 shows a rivet-like metal bolt as holding-down device
for minicables.
[0042] FIG. 12 shows a plan view of the sketched construction of a
bending device for thin-walled tubular microcables or
minicables.
[0043] FIG. 13 shows the laying channel filled with hot bitumen and
coloured glass particles.
[0044] FIG. 14 shows a length-equalizing loop in a longitudinal
section through the road surface along a cut laying channel.
[0045] FIG. 15 shows a sleeve for a tubular microcable or
minicable.
[0046] FIG. 16 shows a laying channel for laying a minicable or
microcable.
[0047] FIG. 17 shows a widened laying channel before the resulting
central web has been broken out.
[0048] FIG. 18 shows the cross-section through the cutting-wheel
arrangement of the laying unit.
[0049] FIG. 19 shows a spacer ring with rectangular grooves on its
outer circumference.
[0050] FIG. 20 shows a spacer ring with sawtooth-shaped grooves on
its outer circumference.
[0051] FIG. 21 shows the arrangement of brushes on the outer
circumference of the spacer ring.
[0052] FIG. 22 shows the lateral offset of hard-metal teeth.
[0053] FIG. 23 shows a laid microcable with a tension-resistant
release element laid in addition.
[0054] FIG. 24 shows a laid microcable with a filling profile as
filling means for the laying channel.
[0055] FIG. 25 shows the electric connection of two minicables or
microcables via a metallic cable sleeve.
[0056] FIG. 26 shows an insulated microcable with an insulated
power cable.
[0057] FIG. 27 shows a non-insulated microcable with an insulated
power cable.
[0058] FIG. 28 shows a non-insulated power cable with an insulated
microcable.
[0059] FIG. 29 shows an insulated microcable with a cable
holding-down device.
[0060] FIG. 30 shows a microcable with an additional cable in a
common insulation.
[0061] FIG. 31 shows an embodiment according to FIG. 30, but with a
web consisting of insulation material located in between.
[0062] FIG. 32 shows two electrically insulated minicables or
microcables.
[0063] FIG. 33 shows two minicables or microcables within a common
insulation.
[0064] FIG. 34 shows a sketch of the process being carried out.
[0065] FIG. 35 shows the laying of the minicable or microcable with
magnet-containing cable holding-down devices.
[0066] FIG. 36 shows U-shaped, magnetic cable holding-down devices
in the laying channel.
[0067] FIG. 37 shows bar-like, magnetic cable holding-down devices
in the laying channel.
[0068] FIG. 38 shows bar-like cable holding-down devices which are
lined up in a row on support filaments.
[0069] FIG. 39 shows a cable holding-down device which has its ends
clamped on support filaments.
[0070] FIG. 40 shows a cable holding-down device which is fitted
into a support sheet.
[0071] FIG. 41 shows the laying of the microcable with electronic
signal generators as holding-down devices.
[0072] FIG. 42 shows a chip which can be freely programmed from the
outside, is fitted along the microcable and is lined up on support
filaments.
[0073] FIG. 43 shows a programmable chip which is accommodated in a
sleeve.
[0074] FIG. 44 shows a defective microcable.
[0075] FIG. 45 shows a plan view of the repair location.
[0076] FIG. 46 shows a cross-section of the repair location.
[0077] FIG. 47 shows a unit for exposing the laying channel.
[0078] FIG. 48 shows a foam-rubber element introduced in the
longitudinal direction.
[0079] FIG. 49 shows a laying channel with a profile body of
circular cross-section before the compression operation.
[0080] FIG. 50 shows the laying channel after it has been closed
off.
[0081] FIG. 51 shows a laying unit.
[0082] FIG. 52 shows a longitudinally slit, annular profile body
which is fitted on the microcable.
[0083] FIG. 53 shows the arrangement according to FIG. 52 after the
laying channel has been filled.
[0084] FIG. 54 shows a profile body with longitudinally running
free ducts.
[0085] FIG. 55 shows the profile body according to FIG. 54 in the
laying channel.
[0086] FIG. 56 shows a profile body which is coated with a
sealant.
[0087] FIG. 57 shows an exemplary embodiment for heating the
sealant during the laying operation.
[0088] FIG. 58 shows the covering profile after the laying
operation in the laying channel.
[0089] FIG. 59 shows a cross-section of the mechanical influence of
the pointed object.
[0090] FIG. 60 shows a front view of the influence of the object on
the covering profile.
[0091] FIG. 1 shows the construction of a tubular microcable or
minicable 1, the cable end 2 being provided with a drawing-in or
drilling tip 5. The arrow 6 indicates the drilling movement or
advancement direction of the drilling head. Running in the interior
of the minicable 1 are the optical waveguides 3, which may be
introduced either at the factory or after the laying operation. The
outer surface of the minicable is provided with a surface
protection 4.
[0092] FIG. 2, then, shows the tube 8 of the minicable 1, in the
interior of which, that is to say in the central duct of which,
optical waveguides have not as yet been provided. In this case, the
said central duct serves initially as a pressurized jetting duct
for the laying operation. Thus, an appropriate medium, for example
a suitable liquid, is injected under pressure, with the result that
the earth is jetted out and displaced at the end 11 of the
minicable. In addition, rotating movement of the drilling tip 10 in
accordance with the arrow directions 12 can increase the action.
Following the laying operation, the optical waveguides or so-called
blown-fibre conductors are then introduced into the tube 8 of the
minicable 1. On the left-hand side of the minicable, the letter P
symbolizes the pressure, required for the jetting process, by which
the medium is injected. If a valve is provided at the end of the
drilling tip 11, corresponding control allows the liquid to be
pulsed out under pressure. At the same time, the tube 8 could
increase and decrease in diameter in an oscillating manner, this
eliminating static friction with respect to the earth.
[0093] FIG. 3 displays a method of laying a tubular minicable in
the sand, gravel, earth or asphalt with the aid of a laying unit
23, by means of which a laying channel 19 is cut in the surface 14
of the ground 17. Covering slabs or cobble stones are removed
beforehand. The machine comprises a linkage 22 on which the
required individual parts are combined to form a unit. All the
process steps are coordinated with one another. In the case of the
laying channel 19 which is to be provided in the laying direction
21, a cutting wheel 15 with corresponding cutting teeth, which cut
a thin laying channel 19 with steep side walls, leads. The width of
the laying channel is just sufficient to receive the tubular
minicable 1 and the laying blade 18. Said laying blade 18 protects
the side walls against caving in, guides the minicable 1 along and,
via a cable-fixing means 7, holds constantly at the laying depth
that end of the cable which is to be laid, the minicable or
microcable 1 being fed from a ring, which is wound up on a laying
reel 24, via advancement rollers 25. A jetting rod 16 compacts the
deposited earth or filling sand 20 behind the laying blade 18. This
operation takes place directly after the excavating operation. It
is thus not possible for the side walls of the laying channel in
the region 13 of the laying machine to cave in. Surrounding earth
will not cave in, with the result that the surface 14 will not
sink. The cutting wheel 15, the laying blade 18 and the jetting rod
16 together form the laying unit 23 and are connected rigidly to
one another via a linkage 22. A drive 30 moves the entire laying
unit 23 continuously in the laying direction 21. The end 29 of the
minicable is introduced at the beginning of the laying channel 19
via a so-called laying bow 26 and a laying thimble 27. The central
connection 28 for pressurized water jetting is provided on the
laying unit 23. Following the laying operation, the road surface is
restored or sealed.
[0094] Such laying operation gives particular advantages since all
cable types with a small diameter can be laid, the outlay being
essentially lower than for conventional laying with a wide trench.
During the laying operation, the minicable is both drawn by the
laying blade and guided along by the advancement rollers. Pulling
and pushing of the minicable during the laying operation can reduce
the tensile loading. Moreover, the tubular design of the minicable
prevents buckling during laying in the channel. Excavating, laying,
filling in and sealing the ground take place directly one after the
other and constitute a precisely coordinated operational sequence.
The cable is supported by the very narrow laying channel, with the
result that the risk of buckling is reduced. Moreover, in the case
of such a narrow laying channel, the soil mechanics and the surface
of the ground are only minimally disturbed, so that post-treatment
is not necessary. The coordinated operational sequence does not
allow the side walls of the laying channel to collapse, so that the
soil is also prevented from caving in afterwards. If the
blown-fibre method is used for introducing the optical waveguides,
one or more hollow tubes are laid, as a result of which pressurized
water may then be channelled directly onto the cutting wheel. This
loosens the rocks or the subsoil.
[0095] FIG. 4 illustrates the system for the forcing-in process, by
means of which a minicable 1 is forced into a disused supply line
31. It is indicated that the minicable 1 which is to be forced in
may, for example, also come up against accumulation of dirt 32
which constitutes blockage of the supply line. Corresponding
pressure has to be used to pass through this accumulation of dirt
32. This figure further illustrates that the disused supply line 31
may have a plurality of branchings, so that it would also be
possible for minicables to be introduced from there. Valve openings
33 which are originally used for the supply line and are each
provided with a covering could be utilized for sleeve inserts for
the newly introduced minicable system. At the start of the
injection location, the minicable 1 is likewise introduced via a
so-called laying bow 26 and a laying thimble 27, advancement being
effected, for example, once again by means of advancement rollers
25. Here too, the minicable 1 is drawn off from a laying reel 24.
It is also possible here for pressurized water to be injected, via
a central connection 28 for pressurized water, to the end location
of the introduced minicable 1.
[0096] FIG. 5 illustrates the introduction of a minicable 1 into an
existing supply line, for example into a water pipe. At a bend 36
of the supply line 35, the minicable 1 is introduced via an outlet
location 37, the inlet location being provided with a corresponding
seal 38. The minicable 1 is advanced within the supply line with
relative ease since there are no expected obstructions. Gas or
flowing water injected into the supply line assist the advancement
of the minicable.
[0097] FIG. 6 illustrates the jetting process for a minitube, which
is then provided with optical waveguides in the second process step
by the blown-fibre principle and thus forms the finished minicable.
As has already been indicated, first of all only the empty minitube
is jetted into the earth 17. In this case, pressurized water is
channelled into the minitube via the central connection 28, this
resulting in the formation, at the end of the drilling head 40, of
a pressurized jetting cone 39 by means of which the earth 17 is
jetted out. The drilling tip 40 is, in addition, made to rotate 41
in order to increase the jetting-out action. The minitube is also
expediently made to rotate 42 at the inlet location. After the
minitube has been laid, the optical waveguides are then jetted or
blown in by the blown-fibre process. The inner wall of the tube is
coated with plastic in order to improve the sliding movement of the
fibre element during the blowing-in operation.
[0098] FIG. 7 illustrates the laying of a microcable in an
asphalted road surface. As a supplement to laying the minicable 1
in a cut laying channel 19, the laying channel 19 is first of all
partially filled with a curable filling foam 43 after the minicable
1 has been laid. Finally, above this filling foam, the laying
channel 19 is filled with a water-tight closure 44, for example
consisting of hot bitumen, with the result that the roadway surface
is sealed off again. It can further be seen from FIG. 7 that a road
structure is made up of various layers. An anti-frost layer 48,
generally comprising crushed stones, has a base course 47 arranged
on it. The latter is adjoined to the top by a binder course 46,
which, finally, is sealed by a surface course 45. It can be
gathered from this that the laying channel 19 must not cut right
through the base course 47, in order that the supporting function
is not impaired.
[0099] FIG. 8 illustrates the position of the laying channel 19 by
a road cross-section with the abovedescribed layer structure
comprising an anti-frost layer 48, an asphalt base course 47, a
binder course 46 and a surface course 45. It is only the surface
course 45 and the binder course 46 which are cut through by the
laying channel 19, the asphalt base course 47 only being cut to a
partial extent. Depending on the nature of the road surface, the
cutting depth is between 4 cm and 15 cm. A laying depth of
approximately 7 cm is optimum.
[0100] FIG. 9 illustrates the same structure as in FIG. 8, but it
is also shown how the laying channel 19 is filled again and closed
off after the tubular minicable has been laid. It can thus be seen
that the base of the channel is provided, around the minicable 1,
with a curable filling foam, over which a bitumen sealing compound
or a preformed bitumen joint filler is introduced in a sealed
manner. It would also be possible for the filling material 49 to be
applied to the microcable, as the cable sheath, at the factory. It
would form an additional protection for laying the microcable.
Suitable means or processes e.g. with the supply of heat, could
make the filling means expand. The laying channel 19 is
consequently sealed off, so that it is not possible for any surface
water to penetrate. Optical waveguides 50 are indicated in the
interior of the minicable 1. In order to rule out damage during
laying and corrosion to the outer sheath of the metallic tube by
leakage currents in the ground, the minicable 1 is provided on the
outer side with a non-conductive protective layer 51 which
insulates the metal with respect to the earth. A thin cable sheath
of plastic can be applied as the protective layer. For this
purpose, a firmly adhering wear-resistant coating may also be
applied. The channel is sealed off with hot bitumen. If a preformed
bitumen joint filler is used to seal the laying channel 19, then it
is introduced into the laying channel 19 on edge and the surface
courses to be connected are heated with a gas flame or infrared
until a liquid bitumen film is obtained. A slight excess of the
preformed bitumen filler is subsequently rolled into the joint and
thus closes off the channel in a water-tight manner.
[0101] FIG. 10 illustrates how the laid minicable 1 is fixed by
U-shaped holding-down devices 52. These U-shaped clamps 52 are
pressed into the cut laying channel 19 from above. In this case,
the web 54 of the clamp 52 holds down the laid microcable or
minicable. Tolerances in the channel width are compensated for by
the spring action of the lateral flanges. The flange ends may be
provided with lateral claws 53 so that they can engage in the side
walls of the laying channel 19. If the filling compound softens,
for example, due to hot temperatures, the cable holding-down
devices 52 hold the microcable or minicable in position without
allowing it to rise up.
[0102] FIG. 11 shows a further exemplary embodiment for cable
holding-down devices 57. These comprise rivet-like metal bolts
which are driven into the cut laying channel 19 by means of their
resilient shank 57. The lens-shaped head 55 terminates at the
roadway surface or is slightly elevated. The cable route is easy to
recognize by the heads 55 of the holding-down devices. The shank of
the cable holding-down device 57 is provided with barbs 56.
[0103] FIG. 12 illustrates a bending device for cable branchings
and equalizing loops for thin-walled tubular microcables or
minicables. In the case of very small wall thicknesses, the
microcable or minicable is very sensitive to buckling. However,
radii down to 30 mm can be produced without buckling by a bending
device 61. For this purpose, the microcable 1 is fixed with
clamping tongues 62 and drawn around a bending mandrel 60. For
simple manipulation, a pressure-exerting roller 59 can draw the
microcable or minicable 1 around the bending mandrel, the hand
lever 58 being actuated in the arrow direction. The pivot point 63
of the hand lever is located in the axis of the bending mandrel
60.
[0104] FIG. 13 illustrates an exemplary embodiment for a marking of
the microcable or minicable route. Such a marking is particularly
important for locating a microcable or minicable and serves, at the
same time, as a warning marking for road construction work. The cut
laying channel 19 is hermetically sealed with a hot bitumen 65. In
this case, the hot bitumen 65 has glass splinters 64, for example,
added to it as filler, with the result that, when light shines
thereon, the course of the laying channel 19 is shown up by the
reflection of light. Hot bitumen usually has a very low viscosity
for processing. For a laying-channel width of from 7 to 10 mm, the
viscosity of the hot bitumen can be increased by aggregates. The
mechanical properties of the sealing compound may then also be
compared with those of the existing road surface. For the marking,
use may be made of ground, coloured glass splinters as fillers and
aggregates. Different colouring and reflection mean that the cable
route may then be recognized clearly. Under normal wear of the
roadway surface, a number of glass particles are always exposed and
are thus easy to recognize.
[0105] FIG. 14 illustrates that the microcable or minicable may be
provided with equalizing loops 66 for length equalization and also
for cable lead-throughs at a sleeve. This means that excess lengths
are taken up during laying and crimping of the tubes and that
subsidence in the earth, in the road and expansions in length in
the microcable or minicable and the road surface are compensated
for without detrimental longitudinal stressing. Such equalizing
loops 66 are to be fitted during laying, in which case the laying
channel 19 has to be provided at the appropriate locations with a
corresponding depression 67 or widening in order to obtain
sufficient space for the equalizing loop 66. Such equalizing loops
66 are preferably to be fitted in front of sleeves, cable branches
and bends. If a microcable or minicable is to be laid at right
angles, then a core hole has to be introduced vertically into the
upper road structure. In this case, the diameter depends on the
minimum microcable or minicable radius which can be bent without
buckling by means of the abovedescribed bending device. The core
hole should subsequently be sealed again in a frost-resistant
manner by asphalt. U-shaped bends of the minicable are also
possible instead of the equalizing loops.
[0106] FIG. 15 illustrates an arrangement for a sleeve 68 into
which microcables and minicables 1 are fed via cable inlets 70. The
appropriate measures such as connecting or splicing are then
carried out in the interior of the cable sleeve. Such a cable
sleeve preferably comprises a round steel cylinder and is
introduced into a core hole of the ground 17. A sleeve cover 69
which can be placed in position from above closes off the sleeve
interior. After the sleeve 68 has been introduced and the
microcable 1 has been introduced in the sleeve, the upright core
hole, which can lead into the substructure of the road, is
concreted into the roadway in the lower region. The sleeve is thus
no longer subject to settling. Sealing with respect to the upper
road structure 72 is effected with asphalt or liquid hot bitumen.
Sealing in the cable inlets 70 takes place, for example, with
conventional cutting ring seals or other seals which are known per
se for cable sleeves. Thin copper tubes into which the cable ends
can be introduced have also proved expedient. These are crimped
onto the outer wall of the microcable by radial pressing. These
crimped connections are resistant to tension and pressurized water.
At the top, the core hole is terminated by a load-bearing cover 73
level with the road surface 72. If necessary, it is also possible
for the cover to be located beneath the roadway surface. The
optical waveguides may be arranged, in a manner known per se, with
excess lengths and splices in the interior of the cable sleeve 68.
The round embodiment of the cable sleeve 68 means that it is
expedient to introduce the optical-waveguides helically, with the
result that they can easily be moved upwards if required.
[0107] It is also advantageous to use a small shaft instead of the
sleeve 68, this small shaft, in turn, receiving a sleeve.
[0108] Discharge means and feed means may likewise be run, as
minicables or microcables, in a manner of an overhead cable or
non-supported cable.
[0109] The object of one development of the invention is to find a
process with the aid of which it is possible to cut laying channels
for minicables or microcables in the solid ground in one operation.
The set object is achieved, in accordance with the process
explained in the introduction, in that a laying channel is cut by
means of a laying unit whose cutting-wheel arrangement is varied in
terms of thickness such that the width of the laying channel is
adapted in one cutting operation to the corresponding diameter of
the microcable or minicable used.
[0110] Advantages of the process according to the development of
the invention may particularly be seen in that it is now possible
to produce laying channels in solid surfaces such as asphalt and
concrete, road surfaces, curbstones or stone slabs by means of a
laying unit in which the cutting width can be set to the respective
diameter of the minicable or microcable used. For this purpose, for
example a cutting-wheel arrangement comprising two standard blades
with the interposition of a spacer ring is drawn onto the axle of
the laying unit. Exchanging the spacer ring means that the cutting
width can thus be changed.
[0111] In the case of wide laying channels, a central web first of
all remains in the ground, but the invention provides measures by
which the resulting central web is broken out at its base during
the cutting operation. This is effected by appropriate
configuration of the circumferential surface of the spacer ring,
e.g. by introducing grooves of a suitable shape, for example of a
rectangular or sawtooth shape, or by providing bar-like, flexible
brushes on the circumference. These also clean the channel of
abrasion dust. This results, in particular, in the advantages
outlined below:
[0112] Production of rectangular laying channels of any width.
[0113] The width of the laying channel can be determined by
exchanging the spacer ring.
[0114] The double cut in one operation means that the wear on tools
is uniform, the blades not being subjected to bending stress, so
that unbalances do not occur.
[0115] The initially produced central web in the laying channel is
broken out at the base during the cutting operation.
[0116] Appropriate configuration of the outer circumference of the
spacer rings means that the laying channel is also cleaned at the
same time.
[0117] FIG. 16 shows a rectangular laying channel VN in a solid
ground surface SO, a double arrow indicating that the channel width
VB has to be variable in accordance with the minicable or
microcable type MK used in order to be able to achieve the
necessary width in a single cutting operation.
[0118] FIG. 17 illustrates the production of the widened laying
channel by two blades which are spaced apart from one another in
accordance with the respectively introduced spacer ring, with the
result that a central web MS first of all remains between the two
partial channels TN1 and TN2. However, appropriate circumferential
configuration of the spacer ring means that this central web MS is
immediately broken off at the base BS during the cutting operation,
this resulting in the wide laying channel shown in FIG. 16.
[0119] FIG. 18 illustrates a cross-section of the cutting-wheel
arrangement, which comprises two blades TS1 and TS2 with a spacer
ring DR located therebetween, the width of the spacer ring DR being
selected such that the ring, together with the two blades TS1 and
TS2, provides the necessary width for the laying channel VN. The
drive axle AS is introduced in the laying unit VE via corresponding
linkages G.
[0120] FIGS. 19 to 22 illustrate the configuration of the
circumference of the spacer ring DR, the blade TS2 having been
removed for this illustration. The blade TS1 is provided with
appropriate cutting teeth in the conventional manner. These cutting
teeth Z may also be provided with hard metal. If appropriate, the
cutters may be exchanged. Preferably, the cutters should be made to
protrude alternately beyond the cutting blade TS3 from the blade
centre, as can be seen from FIG. 22. This screwing action allows
the blade TS3 to cut a clearance at the channel flanks FL.
"Seizing" is avoided. The spacer ring DR is provided on its
circumference with grooves or cutouts of widely varying
configuration which break off the central web and clean the laying
channel. An air pressure by which the laying channel is freed of
fragments is produced by way of the cutouts or grooves. This
simultaneously achieves self-cleaning of the laying channel as it
is produced.
[0121] FIG. 19 illustrates rectangular cutouts RA, and FIG. 20
illustrates sawtooth-shaped cutouts SA, on the outer circumference
of the spacer ring DR. In FIG. 21, this operation is carried out
with the aid of bar-like, flexible brushes B by way of which the
central web is broken and the fragments are removed from the laying
channel VN.
[0122] FIG. 22 illustrates the lateral offset or staggering of the
hard-metal teeth Z, which make it possible for a blade TS3 to run
freely. This arrangement applies for each of the blades.
[0123] It is also possible to use such cutouts RA to cut out a
material which has the properties of bitumen.
[0124] The object of a further development of the invention is to
find a process by which the laid minicable or microcable can be
removed again from the laying channel, in which case the filling
material has to be removed beforehand. The set object is achieved
according to the invention, in accordance with a process of the
type mentioned in the introduction, in that a tension-resistant
release element for lifting the laid minicable or microcable is
introduced, when said cable is laid in the laying channel, above
the minicable or microcable in the filling material of the laying
channel, in that the tension-resistant release element is then
drawn out during the lifting operation, in which case the laying
channel is also released of filling material, and in that the
minicable or microcable is then removed from the laying
channel.
[0125] The problem with lifting the minicable or microcable (only
the term microcable will be used from now on) is that the cable
runs in a laying channel which is covered in a sealed and
well-adhering manner with a filling material above the microcable.
In this case, use is made of a filling material which has viscous
and adhering properties, for example bitumen. Accordingly, the
microcable cannot be drawn out before not the filling material is
removed. Likewise, further, secondary cutting of the laying channel
is not an option since the filling material would only smear on
account of its viscous consistency. The invention solves this
problem, then, in that a tension-resistant release element is
embedded above the microcable, which release element can be drawn
out or pulled out if required and also removes the filling means in
this operation. It is advantageous here if, from the outset, the
microcable is not wetted with the filling means, so that, as far as
possible, there is no adherence between the two. The
tension-resistant release element may be designed as a separate
element, for example in the form of a line, of a profile body or of
a strip. Such release means may consist, for example, of plastic or
of metal, for example of steel. However, it is also possible for
special release means or plastic materials to be applied around the
microcable, for example a plastic film of polyethylene, so that
adherence between the microcable and the filling means occurs only
negligibly, if at all. Furthermore, it is possible for this purpose
that the laying channel be filled above the microcable with a
release means which is designed as a filling profile and is pressed
into the laying channel, if appropriate with additional sealing
with respect to the borders of the laying channel. Once again, a
viscous material such as bitumen is particularly suitable for this
purpose. Particularly elastic materials, for example rubber or
elastic plastics, are suitable for such a filling profile.
[0126] However, the tension-resistant release element may also form
a constituent part of the sheathing of the microcable, it being
possible for the sheathing material to be separated easily from the
microcable, so that, once again, the filling material is first of
all removed with the tension-resistant release element during the
lifting operation.
[0127] If the tension-resistant release element consists of
electrically conductive material, it may also be used, in addition,
for the power supply along the microcable.
[0128] It is illustrated in FIG. 23 that a microcable MK is
introduced in the cut laying channel VN of the solid ground VG and,
according to the invention, a tension-resistant release element ZT
in the form of a metal or plastic line has been arranged above said
microcable during the laying of the same. Above this, the laying
channel VN is filled in a sealed manner with a filling material FM,
for example consisting of bitumen. Before the microcable MK is
lifted, the tension-resistant release element ZT is, then, drawn
out in order also to remove the filling means FM from the laying
channel VN, this resulting in the laying channel VN then being free
and it being possible to lift the microcable MK without risk.
[0129] FIG. 24 shows that it is also possible for the laying
channel VN to be filled with a tension-resistant filling profile
FP, which is drawn out if required. This tension-resistant filling
profile FP may additionally be introduced with a sealant, for
example with bitumen, this resulting in the laying channel VN being
sealed reliably.
[0130] The object of a further development of the invention is to
provide a process for the power supply of a minicable or microcable
with optical waveguides. The set object is achieved, by a process
of the type mentioned in the introduction, in that the metallic
tubes of the microcables or minicables are connected to the central
power supply.
[0131] In general, at the present time, the power is supplied by an
additional power cable which is supplied from a central point. The
disadvantage is that a separate power cable has to be laid over a
large distance. Costs for an additional cable route and voltage
losses have to be accepted. Additional measures for the power
supply likewise have to be taken for the optical-waveguide
submarine cable known per se.
[0132] However, a minicable or microcable of the type described
comprises a tubular metal sheath. This protects the optical
waveguides against damage during laying, guarantees a certain
excess length of the fibres and is stable with respect to
transverse forces. Moreover, the solid ground in which the laying
channel is provided gives the minicable or microcable the necessary
protection against external mechanical influences. The electric
properties of this minicable or microcable, however, are not
utilized. If, then, the metal tubes of these minicables or
microcables are electrically interconnected at the connecting
locations, as is effected, for example, with the aid of metallic
connecting sleeves, this system can be used for a power supply. A
second conductor may provide the return conductor or, if it is
insulated, the power supply. With the return conductor, insulation
may be dispensed with if required. The return conductor may
additionally assume protective functions.
[0133] Such a minicable or microcable and the power supply may also
be produced as a continuous cable. A separate return conductor can
be dispensed with if two insulated microcables are laid. Use may
also be made of two microcable tubes in one microcable with
corresponding common insulation. The cable sheath insulates the
tubes with respect to one another and to the earth. Such a
minicable or microcable can easily be bent around a narrow axis and
laid.
[0134] With such a power supply, the strength and the conductivity
are realized by way of the cross-section of the cable sheath or of
the metallic tube. Sufficient electrical interconnection is
guaranteed by crimping metallic sealing heads of a cable sleeve to
the metallic tube of a minicable or microcable. For the return
conductor of the power supply, use may also be made, for example,
of cable holding-down devices, if these consist of metal. The task
of these cable holding-down devices is, in the original sense, to
position the cable securely at the correct laying height in the
laying channel. When direct current is used, it is also possible to
dispense with a return conductor if earthing takes place. If the
metallic tubes of the minicables or microcables are provided with
an insulation layer, then, in addition to the possibility of
insulated power supply, the following advantages can also be
achieved:
[0135] corrosion protection for the metal
[0136] the metal tube is protected against mechanical damage during
laying
[0137] the insulation layer forms a wear layer for the drawing-in
operation of the microcable
[0138] the insulation layer forms heat insulation when sealing the
laying channel with hot bitumen
[0139] the insulation layer forms vibration insulation in the case
of heavy traffic.
[0140] FIG. 25 shows the through-connection of the power supply
with the aid of a metallically conductive cable sleeve KM. The
power is supplied through the microcables MK1 and MK2, the ends of
which are electrically interconnected by the sleeve tube MR. The
electric contacting, the relief of tension and the sealing of the
microcables MK1 and MK2 take place at the crimp locations of the
sealing heads DK. In this case, the outer side of the cable sleeve
KM is additionally provided with an electric insulation IS.
[0141] FIG. 26 illustrates in the position of a microcable MK which
[lacuna] in the laying channel VN above a power cable SK provided
with an insulation SKI.
[0142] This power cable SK is a single-phase power cable and the
tube MKR of the microcable MK is provided with a plastic insulation
IS. After the introduction of the cables, the laying channel VN in
the ground VG is filled with a sealing compound VM. The power is
thus supplied via the insulated microcable MK and the insulated
power cable SK.
[0143] FIG. 27 shows the arrangement of a non-insulated microcable
NK with its metallic tube MKR, in which the optical waveguides are
arranged, above an insulated power cable SK, within a laying
channel VN. The single-phase power-supply cable SK is, once again,
insulated and the non-insulated tube MKR of the microcable MK is
earthed. In this case, an insulation can be dispensed with.
[0144] FIG. 28 shows the power supply through a microcable MK whose
tube MKR is provided with an insulation IS. Above this, an earth
strip, as return conductor RL, ensures the return conduction. In
this case, the return conductor RL serves simultaneously as
additional protection for the microcable MK.
[0145] FIG. 29 shows the laying of a microcable provided with
insulation IS, in which case a continuous cable holding-down device
NH secures the introduced cable MK in its vertical position. The
cable holding-down device NH has obliquely positioned side walls
NHS which are supported against the wall of the laying channel VN.
In this case, return conduction of the power supply takes place via
the cable holding-down device NH, which serves moreover as an
upward protection and guard.
[0146] FIG. 30 illustrates the power supply through a microcable MK
which is arranged, with an additional wire ZS, with an insulation
IS. Said additional wire ZS is electrically insulated with respect
to the microcable MK. Moreover, the material of the additional wire
is determined such that it can be used as a supporting wire with
the necessary nominal tensile force. It consists, for example, of
steel or bronze.
[0147] FIG. 31 shows the power supply, once again, via a microcable
MK. An additional wire ZS is integrally moulded on the microcable
MK via an insulation IS, the connection between the two taking
place via a web ST. The microcable MK may be separated from the
additional wire ZS in the region of the web ST if required. Such a
separation is practical, for example, for bridging connecting
sleeves.
[0148] FIG. 32 shows the arrangement of two microcables MK1 and MK2
located one above the other in the laying channel VN. The two
microcables MK1 and MK2 are insulated separately and can be laid
separately from one another or together. Each microcable may
expediently be spliced to a single sleeve and electrically
interconnected.
[0149] FIG. 33 shows the power supply through two microcables MK1
and MK2 which are located one above the other and are insulated
separately, but are connected to one another via a web ST. For
splicing, the microcables MK1 and MK2 can be separated from one
another in the region of the web ST, with the result that each
microcable MK1 or MK2 can be spliced in different single sleeves
and electrically interconnected.
[0150] The object of a further development of the invention is to
find a process with the aid of which a laid minicable or microcable
can be located. The set object is, then, achieved, in accordance
with process of the type mentioned in the introduction, in that the
route of the optical minicable or microcable laid in a laying
channel is followed with the aid of a detector.
[0151] Advantages of the invention over the prior art can be seen,
in particular, in that, with the aid of a detector, the laid
minicable or microcable can be traced so accurately that, for
example, it can even be entered, with relatively low tolerances,
for archiving in town street plans and cable-route plans. The
process using a detector according to the invention can also be
used to locate the cable in the ground for repair purposes, it
being possible for interruptions in the cable to be localized
accurately. It is just as important, before the laying channel is
cut, to check the route as to whether or not there are already
supply lines in the ground. Such a process, which is based on the
operation of suitable detectors, can thus be used for the
acceptance and approval of a new cable route, since the quality of
laying and the laying depth can be established at any time.
[0152] It is thus expedient to arrange such a detector, as a
functional unit for locating cables, in front of a joint-cutting
machine, so that any metallic object, for example a cable or supply
line, which is located in the ground, is detected in each case. For
laying minicables or microcables, detection can take place via the
metal tube itself, via a return conductor which is carried along or
else via cable holding-down devices in the laying channel. These
cable holding-down devices may also be used, for example, for the
power supply and for a protective function for locating the
minicable or microcable. It would be possible for holding-down
devices to have a fixedly predetermined code or else to be freely
programmable. A service vehicle which is used to trace the laid
cable is expediently made available for this process. This unit
produces the reference for a marking points, and stores the route
in which the optical cable is laid, so that the route can be
transferred onto existing street plans. In this way, both the
position and the depth of the laid microcable can be
established.
[0153] FIG. 34 describes the principle of the process for locating
an optical cable, in particular a minicable or microcable, with the
aid of a detector D which is accommodated in a service vehicle.
When this vehicle drives over a laying channel VN, it is
established by way of the emitted and reflected locating signal OS
that a laying channel VN has been driven over. In this exemplary
embodiment, the microcable MK has been laid in the laying channel
VN, and the laying channel VN has then been filled with filling
material, for example bitumen, metallic fillers having been added
to the filling material.
[0154] FIG. 35 shows a longitudinal section through a laying
channel VN in solid ground VG. The microcable MK is introduced at
the base of the laying channel and is held in position with the aid
of cable holding-down devices NH, which are of a dowel-like design.
The individual cable holding-down devices NE are provided with
magnets whose magnetic fields can be located by the detector
passing over them. The alignment of these magnets may be the same
or else alternately different in all of the cable holding-down
devices NE. Alternate alignment of the magnets M with the poles MN
and MS can produce a system of alternate magnetic fields by means
of which it is even possible to establish a coding for the laid
minicable or microcable. The laid cables can be identified
accurately in this manner, with the result that it is possible to
rule out mix-ups during repair work.
[0155] FIG. 36 illustrates a laid microcable MK, in the laying
channel VN, which is held in position by magnetic cable
holding-down devices NHN. Here too, poles of the magnetic cable
holding-down devices NHM may be clamped in the laying channel VN
with alternate orientation of the magnet poles NEMN and NHMS, so
that coding of the cable route is possible in this case as well.
The U-shaped cable holding-down devices NHN wedge in during laying
and are supported on the channel wall. The U-shaped cable
holding-down devices are magnetically insulated with respect to one
another and are pressed in individually by the cable-laying
machine. These magnetic cable holding-down devices NHM may be
permanently magnetic or magnetized individually during laying. Here
too, the magnetic field can be detected through the filling
material, which is not illustrated in this case.
[0156] FIG. 37 illustrates, once again, a microcable MK laid in a
laying channel VN, this microcable being held in position by
bar-like cable holding-down devices SNHM. These bar-like cable
holding-down devices SNEM likewise wedge in during laying and are
supported against the channel wall. Once again, the bar-like cable
holding-down devices SNEM are magnetically insulated with respect
to one another, and may be permanently magnetic or only magnetized
individually during laying. Here too, it is possible to allocate an
individual coding (morse) to each laid optical cable by alternating
the magnet poles. It is also possible in this case, in the manner
described, for the magnetic field to be detected by a detector in
accordance with the process according to the invention.
[0157] A grid-like cable holding-down device GNE is illustrated in
FIG. 38. Here, the bar-like, magnetic cable holding-down devices
SN, HM are fastened on two longitudinally running support filaments
TF, the individual bar-like, magnetic cable holding-down devices
SNHM being magnetically insulated from one another. During the
laying operation, this grid-like cable holding-down device GNH can
be easily unwound and introduced above the cable in a clamping
manner. Such a structure can also be used in a simple manner to
measure the length of the cable route since a kind of graduated
scale is provided by the uniform spacing of the bar-like cable
holding-down devices SNHM. The individual bar-like cable
holding-down devices SNHM may be permanently magnetic or only
magnetized individually during laying. Here too, it is possible to
provide a coding by alternating the magnet poles.
[0158] FIG. 39 illustrates that the cable holding-down devices KNHM
can be, as it were, tacked or clamped onto the support filaments
TF. This may also take place on site, in which case any desired
coding pattern can be produced. Such a coding may also take place,
for example, by varying the spacing between the individual
bar-like, magnetic cable holding-down devices KNHM.
[0159] It is illustrated in FIG. 40 that the cable holding-down
devices ENHM may also have their ends E fitted onto a support sheet
TFOL. Here too, it is possible to vary the polarity and the spacing
of the individual bar-like cable holding-down devices ENHM for a
corresponding coding. During filling of the laying channel with hot
bitumen, the sheet then melts, with the result that the hot bitumen
can fill the laying channel between the bar-like magnets ENHM. The
bar-like cable holding-down devices ENHM remain wedged in the
laying channel and hold the microcable in the corresponding
position.
[0160] In addition to the abovedescribed possibility of purely
passive coding by cable holding-down devices NH, an active coding
provided by electronic components is illustrated in FIG. 41. FIG.
41 is derived from FIG. 35. However, the magnets have been replaced
by electronic pulse generators I. The information of the pulse
generators I can be interrogated from the road surface by a movable
induction loop IS.
[0161] The pulse generators I can emit cable-specific information,
e.g. operator name, route to which the relevant cable belongs,
laying depth, laying date, number of optical waveguides, etc.
[0162] A freely programmable chip C which is assigned to the
microcable MK or to the holding-down device NH is illustrated in
FIG. 42.
[0163] It can store and reproduce information (cable, sleeve,
operator, free optical waveguides, etc.). Interrogation can take
place inductively via the support filaments (TF) or by electrically
contacting the cable sheath or the carrier filaments from the
sleeve.
[0164] In FIG. 43, the programmable chip CH is accommodated in the
sleeve M, so that information can be emitted from the sleeve. It is
also possible for further electronic active components to be
accommodated here. The power supply can take place from here, it
also being possible for the support surfaces TF of the cable
holding-down devices NE to be designed, for example, as
power-supply conductors.
[0165] The abovementioned optical cables are referred to as
microcables and are preferably laid in laying channels in solid
ground. On account of their small diameters, the laying channels
can be kept very narrow, so that they can be produced with the aid
of cutting processes. Particularly suitable laying surfaces are
substructures and roads consisting of asphalt or concrete. The
laying depth is very small and is between 7.5 and 15 cm. Such
optical-waveguide cable systems are particularly wellsuited for
laying in surfaces which have already been established for this
purpose, since high-outlay excavation work does not have to be
carried out. Moreover, the laying time is very short, which is
particularly advantageous in the case of roads. After the
introduction of the microcables into the cut laying channels, these
are filled with suitable filling material, for example with
bitumen. Further examples of suitable laying channels are expansion
joints which are provided between individual concrete slabs or are
provided as a precautionary measure in concrete slabs for road
surfaces. Microcables may likewise be laid in these expansion
joints. These expansion joints are likewise filled with filling
material, so that the microcables are protected.
[0166] However, it must also be possible for such microcables to be
lifted, for example when repair work has to be carried out on the
tube. These microcables cannot, however, be removed from the laying
channel together with the filling material since the forces
required for this purpose would damage the microcable further.
Moreover, the tube has to be restored in the region where damage
has been established and then introduced into the laying channel
again.
[0167] A further object of the invention is to develop a process by
which it is possible to remove a microcable of the abovedescribed
type from the laying channel and to repair the same. The set object
is, then, achieved, with the aid of a process of the type mentioned
in the introduction, in that, with the aid of a unit for exposing
the microcable, the filling material is removed from the laying
channel over a length which is required for the introduction of a
repair set, said repair set being formed from two cable sleeves,
two equalizing loops and a connecting tube between the cable
sleeves, in that the microcable is lifted from the laying channel
freed of the filling material, in that the tube of the microcable
is shortened over a length which corresponds to the repair set and
in that the repair set is connected tightly to the two ends of the
microcable.
[0168] Microcables of the abovedescribed type are laid in the upper
region of roads and footpaths. In terms of dimensions, they are
very small and could thus easily be overlooked when earth work is
carried out, so that the possibility of damage is considerably
higher than in the case of conventionally laid communication
cables. It is thus necessary to have a quick process for repairing
a damaged microcable, by means of which the damage can be rectified
in a relatively simple manner and in a short period of time. A
repair set is designed for this purpose, which set is made up of
existing standard parts, that is to say of two cable sleeves with a
connecting tube located therebetween, this connecting tube bridging
over the length of the damaged area, and of two connection units
which are connected to the ends of the damaged microcable. The
damage location, for example a cut-through tube of the microcable,
may be located, for example with the aid of an electric test
signal, by radiation. However, if the tube is still connected
metallically, the defect location in the optical waveguide has to
be traced and localized, for example with the aid of an Optical
Time Division Reflectometer (OTDR). In this case, some of the
introduced light is reflected back by way of defect locations in
the glass (soiling, splice, etc.). If the transit time is measured,
the spacing between the defect location and the transmitter can be
measured.
[0169] For the repair, the microcable has to be exposed, on either
side of the defect location, to such an extent that there is
sufficient excess length for manipulation and for splicing in the
cable sleeves. For this purpose, however, first of all the laying
channel has to be freed of filling material since it is not
otherwise possible for the microcable to be lifted without further
damage. The laying channel is exposed by cutting out or scraping
out--possibly in a number of layers--or by heating the sealing
compound, by cutting out and removing with the aid of a cutter
guided in the laying channel, or by heating the microcable or
further electrically heat-conductive parts which may be located in
the channel close up beside the microcable.
[0170] In each of the two cable sleeves, which are suitable for
receiving microcables at least in the inlet region, in each case
one end of the defective microcable is introduced and is spliced
there to optical waveguides, which are guided to the second cable
sleeve via the connecting tube. These optical waveguides are then
spliced, in the second sleeve, to the optical waveguides of the
second end of the defective microcable. The cable sleeves are
expediently sunk in core holes which are cut in tangentially beside
the exposed laying channel. The inlets of the cylindrical cable
sleeves are arranged tangentially on the sleeve cylinder, with the
result that the inlets of the microcable connections in the form of
equalizing loops only have to be deflected to a slight extent. The
microcable connections likewise comprise tubes and are designed as
equalizing loops, so that it is possible to compensate for
tolerances and longitudinal expansion when the sleeves are
introduced and during operation. The tight connections to the
microcables are produced by crimping the ends of the equalizing
loops onto the ends of the microcable. After these operations, the
laying channel can be filled with filling material again.
[0171] A break KB in a microcable NK is illustrated in FIG. 44, the
filling compound having already been removed from the laying
channel over a length which is necessary for the repair. All that
is left in the exposed laying channel FVN, which is provided, for
example, in a solid road surface VG, is a small layer of filling
compound above the microcable NK, which layer of filling compound,
for safety reasons, is not removed in its entirety, so that the
microcable MK is not damaged mechanically by the tool. An
appropriate control means as is further explained at a later point
in the text is suitable for this purpose. The laying channel with
the virtually exposed microcable MK is then accessible from the
road surface SO, so that the two ends of the microcable MK which is
to be repaired can then be removed simply and carefully.
[0172] FIG. 45 illustrates the already outlined process for
repairing a microcable MK which is broken at the location KB, the
exposed laying channel FVN being viewed from above in this case. It
can be seen that two core holes B have been drilled vertically into
the ground, virtually tangentially beside the exposed laying
channel FVN, at a spacing which is required for the excess lengths
of the optical waveguides, and a cylindrical cable sleeve KM has
been introduced into each of the core holes. These cable sleeves KM
are designed for receiving microcables and have tangentially
running cable-sleeve inlets KE to which tubular equalizing loops AS
are connected. The diameter of these tubular equalizing loops AS is
adapted to the diameter of the microcable MK, the tight connections
usually taking place by crimping AR. The equalizing loops AS serve
for equalizing tolerances and expansions. Since the cable sleeves
KM have tangential cable inlets KE, the equalizing loops AS can be
fitted on with only small bends, so that they can be run into the
exposed laying channel FVN without buckling or stressing.
[0173] FIG. 46 shows the arrangement in accordance with the
outlined repair process and constitutes a longitudinal section of
the arrangement according to FIG. 45, for the sake of simplicity
the cable sleeves being illustrated in a sectional and simplified
form in order better to show the conditions. It can thus be seen
that the equalizing loops AS are connected by means of crimping AK,
on the one hand, to the tube ends of the microcable MK which is to
be repaired and, on the other hand, to the cable inlets KE of the
cable sleeves KM. The optical waveguides LWL of the microcable MK
are each fed to the corresponding cable sleeve KM by way of the
equalizing loops AS and, there, are spliced, at splicing units SK,
to optical waveguides LWL which lead, via the connecting tube VR,
to the respectively second cable sleeve KM. All the connections can
be restored in this manner. After the cable sleeves KM have been
closed off, the previously exposed laying channel FVN can be filled
with filling material again.
[0174] FIG. 47 shows a unit GF for removing the filling compound FM
from the laying channel VN provided in solid ground VF. A
microcable MK is laid at the base of said laying channel VN and has
to be lifted, for example, due to a break in the tube. In this
case, the microcable MK is provided with an insulation layer IS.
For the purpose of removing the filling compound FM, use is made,
in this process, of a heated cutter SCH which is mounted
cardanically, that is to say rotatably, at a pivot point DP of the
unit GF and thus compensates for inaccuracies in the guidance of
the cutter. Also provided is a spring mechanism F which is designed
such that the cutter SCH can tilt out upwards if the lifting-out
force exceeds an adjustable value. This cutter SCH is mounted on a
mobile unit GF and is heated, for example, from a container for
fuel BS via a connecting line SH. A motor M ensures that the unit
GF advances above the laying channel VN on the road surface. An
electric measuring device MV is used, during the process, to
monitor that the microcable is not additionally damaged by the
cutter SCH being introduced too deeply, the tube of the microcable
NK and the metallic cutter SCH being connected to a continuity
tester. If, then, the insulation layer IS is damaged by the cutter
SCH, the measuring device MV responds and the depth of engagement
of the cutter SCH may then be corrected. It is also possible for
the exposing operation to take place in layers.
[0175] Further aids may also be provided in order to expose the
microcable in the laying channel. Thus, for example, the insulation
of the microcable may be designed as a type of zip fastener, so
that the tube itself does not come into contact with sealing
material when the latter is being introduced. After the filling
material has been removed and the "zip fastener" has been opened,
the microcable can be completely freely removed from the
insulation. Furthermore, it is also possible for a ripping wire to
be introduced into the laying channel above the microcable, it
being possible for this ripping wire to be used for pulling out the
filling material. If continuous cable holding-down devices have
been introduced above the microcable during the laying operation,
these cable holding-down devices may also be used for removing the
filling material.
[0176] If the microcable has an insulation, this insulation is
extremely suitable as a release means between the metallic tube of
the microcable and the well-adhering filling material (for example
bitumen) which seals the laying channel. A cable sheath consisting
of polyethylene, paper or a swelling nonwoven acts as a zip
fastener as the microcable is exposed, since those materials do not
adhere to the tube but adhere well to the bitumen. Such a cable
sheath thus acts as a release means between the metal tube and the
filling material. The metal tube of the microcable should have a
smooth surface in order to reduce the adherence. The laying channel
is exposed in the abovedescribed manner, but the insulation remains
in the laying channel.
[0177] It is also possible to lay a strand of foam rubber GU as
release means between the microcable MK and the filling material
FM, as is shown in FIG. 48. In such an arrangement, the cutter of
the laying unit would then not have to be heated. It is also
possible to use a particularly strong cable sheath. In addition,
the cable sheath may also be thickened.
[0178] In accordance with the same process, it would also be
necessary to remove a filling material from a laying channel which
are introduced between the individual slabs of a concrete roadway
or in expansion joints of slabs on which it is possible to drive it
would therefore also be possible to dispense with the operation of
introducing an additional channel with the aid of a cutting blade
in the case of concrete roads if these channels in the concrete
have a dimension which corresponds approximately to the diameter of
a microcable, such cables can be introduced into these already
existing channels without further measures being taken. These
channels are then likewise filled with filling material and sealed.
Since such seals in the channels of the concrete slabs have to be
renewed at certain time intervals for safety reasons, there is the
opportunity to use such occasions to lay new microcables without
additional cost, time-saving also playing a role here. Moreover,
the road structure would not be weakened by additional laying
channels for the microcable. It would be possible for the expansion
joints to be made deeper or wider by abrasive grinding.
[0179] Concrete roadways are divided up, directly after casting, by
dummy joints into individual slabs of a size of from 7.5 m to 20 m.
These dummy joints are predetermined breaking points which are
produced by cuts of a depth of approximately 5 to 10 cm and a width
of approximately 8-10 mm. Sealing strip, foam rubber or filling
bitumen seal the dummy joints against dirt and surface water. Such
channels are likewise suitable for the laying of microcables. In
order to protect the microcables laid therein and in order to be
able to compensate for irregularities caused by the soil mechanics,
it is expedient to widen the dummy joint at each concrete-slab
joint, so that the microcable has sufficient opportunities for
compensation in these areas. For this purpose, a core hole with a
diameter of 8 to 10 cm would be sufficient in order to protect the
laid microcable when roadway slabs are displaced with respect to
one another by subsidence, earthquakes or similar ground movement.
Shearing off or buckling of the laid microcable could thus be
largely ruled out.
[0180] The length of the repair set depends on the damage location.
In order to have sufficient excess length of fibre, a fibre supply
of approximately 1.5 m has to be allowed for each sleeve. The
connecting tube VR, and thus the length of the repair set, is
always 3 m longer than the defect location which is to be
bridged.
[0181] The filling material can also be heated, for example, by
heating current-carrying conductors which have been introduced in
the filling material. The cable holding-down devices, for example,
can be used for this purpose.
[0182] The object of a further development of the invention is to
provide a process in which the microcable is fixed continuously
along its length during the laying operation.
[0183] The set object is, then, achieved, by a process of the type
mentioned in the introduction, in that the microcable is fixed in a
laying channel in the ground with the aid of a continuous profile
body consisting of elastic material, and in that the laying channel
is sealed by introducing a sealant.
[0184] The microcable, then, is fixed, in a simple manner and
ideally following the laying of the microcable in the laying
channel, by introducing a continuous profile body at the base of
the laying channel. The continuous, elongate profile body
preferably comprises an extruded, rubber-like plastic, which is
usually referred to as foam rubber. The action of pressing this
profile body into the laying channel deforms it elastically and,
due to the elastic prestressing, wedges it against the walls of the
laying channel. In so doing, irregularities are compensated for by
the elastic material. The material consists of a rot-proof soft
rubber which is resistant to temperature and UV. If required, this
profile body may additionally be sealed at the top with a sealant,
for example with hot bitumen. In this way, the profile body is
additionally fixed mechanically in the channel. This gives the
following advantages over holding-down devices comprising metal
clamps or similar elements:
[0185] Less hot bitumen is required for the sealing.
[0186] The profile body is laid quickly, in some circumstances
immediately after.
[0187] The laying operation can run continuously.
[0188] This alone provides rough sealing with respect to surface
water.
[0189] The elastic material of the profile body can allow for
expansions in the ground.
[0190] There is only slight shrinkage of the hot bitumen in the
sealing area, so that there is hardly any "subsequent
settling".
[0191] The channel filling, comprising the profile body and the
sealant, can be easily removed again since a type of zip-fastener
function is set up.
[0192] The main purpose of the invention, however, is to fix the
microcable in the laying channel with the aid of a profile body.
Furthermore, the channel is sealed towards the road surface and the
cable is protected against mechanical loading and vibration.
[0193] In the simplest exemplary embodiment, use is made of an
elastic profile body with circular cross-section which is pressed
in directly above the microcable, for example using a roller or
roll, the remaining free space in the laying channel being sealed
off towards the top with a hot bitumen. On account of its elastic
properties, pressing in of the profile body also fills the cavities
between the microcable and the laying walls.
[0194] An exemplary embodiment in which the microcable is already
sheathed with an elastic profile body is also advantageous.
[0195] However, use may also be made of dimensionally stable,
elastically deformable sealing profiles, which then have deformable
formations, for example barbs, which make it possible for said
sealing profiles to clamp and catch on the channel walls and
irregularities in the laying channel.
[0196] As sealant for sealing the laying channel against the
penetration of water, use is preferably made of heat-softenable
materials, for example fusible bitumen or hot bitumen or hot-melt
adhesives known per se, e.g. consisting of polyamide. These
sealants are introduced, under the action of heat, after the
microcable has been laid in the laying channel, said laying channel
then being sealed after setting of the sealants.
[0197] Use may also be made of temperature-resistant and
dimensionally stable profile bodies in which there are arranged
free ducts into which microcables or else free optical waveguides
are drawn. The optical waveguides are introduced, then, for example
by cables, fibres or fibre elements being blown or drawn in, it
being possible for these operations to take place before or else
after the introduction of the profile body.
[0198] It is thus possible for a microcable to be fixed in its
laying channel in a simple manner by a continuous profile body, the
cut laying channels in the solid ground, for example a road, being
closed off in a water-tight manner. The microcables can be laid
better using such profile bodies and, in the event of a repair
being necessary, these profile bodies can be easily removed again
from the laying channel. The profile bodies which are introduced
above the microcable simultaneously protect against high
temperatures (from 230 to 280.degree. C.), which may occur when the
hot bitumen or the hot-melt adhesive penetrates. Moreover, it is
also possible for the profile bodies to compensate, to some extent,
for changes in length in the case of irregularities in the road
(subsidence) or in the case of different thermal expansions of
cable and road surface.
[0199] However, the microcables may also be provided during
manufacture with a sheath consisting of soft, as far as possible
cellular or expanded plastic, so that this sheath already assumes
the function of the profile bodies. Such a microcable is then held
down by the applied sheath, which is compressed in the same manner
against the channel walls.
[0200] The profile bodies may thus be introduced into the laying
channel as an endless profile without any joints, the profile
bodies expediently being brightly coloured, so that they
simultaneously provide a warning for subsequent roadworks.
Moreover, the microcable is elastically sealed towards the top, so
that the microcable is isolated from mechanical loading
(vibration). Using a profile body which completely encloses the
microcable provides a uniform radial pressure, with the result that
the cable is aligned without stressing. Since the elongate profile
bodies hold the microcable down uniformly, it is no longer possible
for the microcable to rise up due to inherent stressing of the
same. Moreover, the microcable is not subject, during laying, to
any longitudinal stressing, which could possibly lead to expansion
or tensile stressing of the optical fibres. During the laying
operation, the microcable is routed very accurately, so that the
cable cannot deflect or buckle under the thermal or mechanical
loading. Furthermore, pressing the profile bodies into the laying
channel results in gap-free filling of the interstices in the
vicinity of the channel wall on account of their elastic
properties.
[0201] The microcable may have a sheath extruded on it as early as
the production stage. However, it is also possible to apply a
cylindrical sheathing subsequently, shortly before the microcable
is laid, said sheathing preferably being slit, so that it can be
latched onto the microcable.
[0202] The introduced profile bodies can be cut out in a simple
manner, during repair work, with the aid of a chisel or knife, so
that the microcable which is to be repaired can be lifted in a
simple manner.
[0203] It is also possible for a plurality of microcables to be
arranged one above the other in one laying channel, this providing
the possibility of using a profile body which has a plurality of
longitudinally directed free ducts.
[0204] It is also possible for further microcables to be introduced
subsequently into a laying channel, in which case the profile body
is first of all removed in order to provide space for the further
microcable. A profile body is then subsequently pressed in and is,
once again, closed off towards the top with a sealant.
[0205] If use is made of relatively hard profile bodies, additional
free ducts may run in the longitudinal direction, it being possible
for fibres to be provided therein, for example blown in, at a later
point in time.
[0206] FIG. 49 shows a laying channel VN in solid ground VG, for
example a road surface. The microcable MK has already been
introduced in the base of said laying channel VN. As the arrow GK
indicates, a continuous profile body GU consisting of elastic
material, for example rubber, has been introduced above the
microcable MK as a holding-down device for the same.
[0207] FIG. 50, then, shows that the action of pressing in causes
the profile body GU to mould to the microcable MK and the channel
wall NW. The rest of the laying channel is filled in a sealed
manner towards the top, up to the road surface SO, with a sealant
B, for example a hot-melting bitumen.
[0208] FIG. 51 shows, schematically, the operation of a laying unit
VW. The microcable MK is unwound directly from a drum TMK on the
left-hand side, so that the microcable can be laid easily in the
laying channel. Unnecessary deformation of the microcable is
avoided in this case. A laying shoe VS avoids the situation where
the microcable MK rises up out of the laying channel. Provided on
the right-hand side of the laying unit VW is a second drum TGU for
the profile body GU which is continuously pressed into the laying
channel VN above the microcable MR by a pressure-exerting roller
AR. In this way, in a laying operation, the microcable KM is laid
in the laying channel VN, and fixed by the profile body, in a
simple manner. The laying shoe VS is held in position with the aid
of a spring structure F, and a braking device BR ensures a defined
drawing-off speed for the two drums TMK and TGU. Finally, the
laying direction VR is indicated by an arrow.
[0209] FIG. 52 shows a microcable MK which has already been
provided with an elongate, annular profile body GUR. This profile
body can either be extruded onto the microcable MK during
production or be drawn on subsequently. If the profile body GUR is
drawn on subsequently, it in expedient to provide a longitudinal
slit S, so that the profile body GUR can be latched onto the
microcable MK by expansion. The edges of the longitudinal slit S
are expediently bevelled, to render the latching-on operation
easier.
[0210] FIG. 53 shows a laid microcable MK with a profile body GUR
drawn thereon, the pressing-in operation deforming said profile
body such that cavities are largely eliminated. In this embodiment,
furthermore, an additional profile ZP which additionally closes off
the laying channel towards the top is introduced. The two profile
bodies consist of elastically or plastic material, so that they
lend themselves well to deformation. The rest of the laying channel
VQ is, once again, closed off and sealed with a sealant, for
example hot bitumen B. If it is intended to lift a microcable MR
again, then a chisel is used to remove the sealant B mechanically
and extract it from the laying channel. Since it is only the
sealant and the channel wall which adhere firmly to one another,
the profile body can be easily drawn out after removal of the
sealant. As a result, the microcable MK which is to be repaired is
freely accessible again.
[0211] FIG. 54 shows the cross-section through an elongate profile
body VP comprising a solid profile which has elastic properties,
but cannot be deformed plastically. The profile body is fixed in
the laying channel by elastic barbs WH. Arranged within the profile
body VP are longitudinally running free ducts FK into which fibres
can be drawn or blown at a later point in time. Provided in the
upper region of the profile body VP is a duct for a microcable MK
which is introduced into the profile body VP in the direction GR,
through a longitudinally running slit VPS, before the laying
operation.
[0212] FIG. 55 shows the profile body VP of FIG. 54 within the
laying channel VN, the elastic barbs WE having been wedged along
the channel wall. Additional optical waveguides may possibly be
drawn or blown into the free ducts FK of the profile body VP at a
subsequent point in time. The upper part of the laying channel VN
is, once again, filled with a sealant B.
[0213] FIG. 56 shows a cross-section of a profile body P which
likewise has elastic properties, but cannot be deformed plastically
and has already been sheathed at the factory with a fusible sealant
BVP, for example consisting of hot bitumen or hot-melt adhesive.
This grooved moulding NFT is heated before laying, so that it can
be rolled into the laying channel in the hot state. Free ducts are,
once again, provided in the profile body P, but a slit duct for
receiving a microcable may also be provided here.
[0214] FIG. 57 shows the laying operation for a grooved moulding
NFT according to FIG. 56. Here, use is made of a hot roll WW which
presses the heated grooved moulding NFT into the laying channel VN.
The sealant sheathing the profile body is expediently heated by
heat radiation WS from infrared radiators IS. Before laying, the
laying channel VN is also heated in order to avoid overly rapid
cooling of the sealant. Finally, the excess sealant is rolled in at
the road surface and removed.
[0215] Furthermore, the object of one development of the invention
is to find a process in which the laid minicable or microcable is
sufficiently protected against damage by the penetration of pointed
implements and very sharp-edged objects. The said object is
achieved according to the invention, with the aid of a process for
introducing an optical cable of the type mentioned in the
introduction, in that, after the introduction of the minicable or
microcable into the laying channel, an elastic,
notch-impact-resistant covering profile which is difficult to cut
through by mechanical intervention is laid in the longitudinal
direction of the minicable or microcable, and in that the width of
the laying channel is covered in so doing.
[0216] The advantages of the process according to the invention for
laying optical-waveguide cables, in particular minicables or
microcables, consists essentially in that as early as at the actual
laying stage itself additional protection is afforded for the
optical-waveguide cable against accidental or intentional
mechanical intrusion into the laying channel. Such intrusion in the
route may occur, for example, deliberately as a result of vandalism
or accidentally as a result of work being carried out in the ground
there. Thus, for example, in the case of the penetration of a
pointed and very sharp-edged object, for example a screwdriver or
chisel, penetration as far as the microcable is prevented. This
results in elastic/plastic deformation of the tough and resilient
covering profile, which comprises, for example, a metal-wire core
and an elastic sheathing consisting of plastic material.
Intermediate coverings which run directly above the microcable may
additionally be introduced during the laying operation. Wires for
reinforcing the mechanical strength and sensors for information
which is to be called up may additionally be introduced into these
intermediate coverings. Such sensors may be used, for example, to
locate and monitor disruption-free operation. The toughened
resilient core essentially prevents the penetration with a
sharp-edged object. The foam sheathing, on the other hand, cushions
the additional loading and distributes the compressed loading over
a large surface area, so that the minicable or microcable is not
deformed or damaged any further. In addition, this also provides a
simple lifting aid for the optical-waveguide cable, since the
tensile strength of the covering profile is sufficient for removing
from the laying channel the filling material which is located above
said covering profile. The covering profile also serves, at the
same time, as the holding-down device for the optical-waveguide
cable in the laying channel and, in the case of metal inserts, can
also function as an earthing strip.
[0217] FIG. 58 illustrates the cross-section of a laying channel
VN, at the base of which a microcable MK is laid. An intermediate
covering ZWA is additionally introduced, after or during the laying
of the microcable MK, on said microcable MK located beneath it.
This additionally produces buffering against mechanical action from
above, with the result that directed blows with a tool or similar
pointed object cannot deform or even cut through the microcable MK.
Said intermediate covering ZWA may, if appropriate be provided with
inserts ZWE, for example with metallic wires, or with sensors. Such
sensors can be used at a later point in time to locate the cable
routing as well as penetrating water or disruptions in the road
structure and to trace the intrusion. With an intermediate covering
ZWA consisting of conductive material, it is also possible for the
tube MKR of the microcable MK to be manufactured from plastic
instead of metal, it being necessary for the corresponding boundary
conditions as regards tensile strength and transverse compressive
strength to be observed. The covering profile AP on which the
invention is primarily based is then likewise introduced above this
intermediate covering ZWA after or during the introduction of the
microcable. Said covering profile AP may, in principle, be designed
as a metal-wire, plastic, hemp or sisal line, it being necessary
for the material used to have the corresponding properties. This
means that the covering profile AP has to be designed so that it is
difficult to cut through, can be deformed mechanically to a limited
extent and is tough and resilient, which can be achieved, for
example, by stranding individual elements. However, it is
advantageous if such an element is coated, as core MFK, with an
elastic sheathing APU, preferably consisting of foam material, it
being necessary for the diameter of the overall covering profile AP
to correspond to the width of the laying channel VN, such that
clamping in the laying channel is also achieved therewith. The core
MFK itself has to have a thickness which corresponds at least to
the diameter of the microcable, so that the covering profile AP
with its core MFK provides the microcable MK with full covered
protection. The rest of the laying channel VN is filled towards the
top, towards the surface of the ground VG, with a filling material,
preferably with hot bitumen. Such a covering profile AP thus
provides considerable protection against accidental or intentional
penetration of destructive objects into the laying channel VN, the
tough and resilient core MFK largely preventing the penetration of
a sharp-edged object. In this case, the sheathing APU consisting of
elastic material cushions the loading and distributes the
compressive loading over a large surface area. The microcable MK
located therebeneath is not deformed or damaged. However, the
intermediate covering ZWA shown in this figure does not have to
form part of the arrangement if the covering profile AP meets the
required conditions itself. Moreover, the mechanically strong
structure of the covering profile AP may also be used as a simple
lifting aid for the microcable MK since, on account of the high
mechanical strength, it can be used, if required, to draw out from
the laying channel VN the filling material FM located
thereabove.
[0218] FIG. 59 illustrates assumed mechanical loading by a pointed
object SG which is driven with a force P into the laying channel
filled with the filling material FM. In this operation, the filling
material PM is displaced and the object SG comes into contact with
the elastic sheathing APU of the covering profile AP. In this case,
the sheathing APU is deformed, or even cut through, but the pointed
object SG then comes up against the core MFK, which is difficult to
cut through, of the covering profile AP, where it is finally
stopped. That side of the sheathing APU which is located
therebeneath is deformed by the pressure produced, and a
distribution of pressure takes place. The microcable MK located
therebeneath, which in this case is arranged beneath the
intermediate covering ZWA, is thus not damaged.
[0219] FIG. 60 illustrates the operation according to FIG. 59 in
cross-section. It can clearly be seen that, when it comes into
contact with the covering profile AP, the pointed object SG
deforms, or else cuts through, the sheathing APU and is then
prevented from advancing further by the core MFK, otherwise, the
conditions correspond to FIG. 59.
* * * * *