Optical waveguides – Optical transmission cable
Reexamination Certificate
1999-10-28
2001-06-12
Spyrou, Cassandra (Department: 2872)
Optical waveguides
Optical transmission cable
C385S109000, C385S110000, C385S112000, C138S111000, C138S112000, C138S113000, C138S115000, C138S116000, C138S117000, C165S154000, C165S162000
Reexamination Certificate
active
06246820
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for placing a structural element in a cable installation conduit in order to sub-divide it. It relates especially to a method to position this structural element by means of the device of the invention.
Many networks presently consist of unitary conduits in order to obtain the circulation therein of a fluid or to take a cable for the conveyance of power or telecommunications signals.
2. Description of the Prior Art
The present-day optical fiber cables used in the new optical fiber telecommunications networks are highly dense (with high-capacity micro-sheathed or ribbon cables) or again very compact for low-capacity cables such as multiple-core fiber cables for example.
In the development of these new optical fiber telecommunications networks, FRANCE TELECOM has envisaged the optimizing of the available volume in the cable installation conduits by developing a multi-alveolate structural element designed to sub-divide a conduit. The fitting of such a structural element into a conduit has been envisaged in order to lay a larger number of cables in a conduit and to make them independent of one another, thus preventing the strains induced by the laying of a new cable from getting applied to cables already positioned in the structural element.
Thus, the French patent FR 2 730 101 describes a flat-conditioned multi-alveolate structural element designed to divide a cable installation conduit into several sections. The development of this structural element is recent. Hence, no device or method has yet been seriously designed to position it in a cylindrical conduit. Until now, the structural element has been given a cylindrical shape by having its ends clipped together, and it is cold-inserted into the conduit without any special precautions being taken.
The fact of keeping the structural element in its cylindrical shape (by clipping) leads to its embrittlement. The structural element tends to become more easily breakable, and its resistance to mechanical impact as well as to torsional and bending forces is greatly reduced. Furthermore, the fact that the structural element is cold-inserted into the conduit without any preliminary action on it causes the appearance of major frictional forces. All these problems thus prevent the laying of the structural element over great lengths. The laying lengths are indeed far smaller than the minimum required distance which is 300 meters and corresponds to the distance between two underground chambers.
The present invention makes it possible to overcome the drawbacks of the prior art. For this purpose, it proposes a simple and low-cost device enabling the placing of a structural element in a cylindrical conduit over a great length without any embrittlement or deterioration of this structural element.
SUMMARY OF THE INVENTION
The invention relates more particularly to a device for placing a structural element in a cable installation conduit, said structural element having a width close to the size of the internal perimeter of the conduit and comprising a plate surmounted by ribs designed to sub-divide said conduit, wherein the device comprises:
a hot air inlet designed to soften the plate of the structural element;
an external cylinder whose diameter is identical to that of the conduit, the cylinder comprising a shaping cone at one end in order to enable the softened structural element to gradually take a cylindrical shape; and
an internal core fixedly held at a position located in the shaping cone of the external cylinder and positioned inside the softened structural element in order to give it a constant internal diameter when it is being shaped.
According to another characteristic of the invention, the device furthermore comprises pre-shaping rods positioned between the hot air inlet and the shaping cone of the external cylinder.
According to another characteristic, the device furthermore comprises rods to guide and hold the structural element that are fixed to the internal wall of the external cylinder and extend beyond its end opposite the shaping cone.
According to yet another characteristic of the invention, the internal core comprises an internal metal tube and an external casing made out of a material having a low coefficient of friction. This material is, for example, made of polytetrafluoroethylene.
According to yet another characteristic of the invention, the hot air inlet is positioned so that it is perpendicular to the plate of the structural element and located at a distance of 10 cm to 30 cm from said structural element.
Another object of the invention relates to a method for the placing of a structural element in a cable installation conduit, said structural element having a width close to the size of the internal perimeter of the conduit and comprising a plate surmounted by ribs designed to sub-divide said conduit, said method using the device according to the invention and comprising the following steps:
a) inserting a first length of structural element into the external cylinder,
b) attaching the end of the first length of inserted structural element to a drawing rope that is itself linked to a winch placed at the end of the conduit,
c) heating the plate of the structural element and carrying out a simultaneous drawing operation so that the structural element:
initially penetrates the external cylinder and gradually takes its cylindrical shape, an internal core being positioned inside the structural element to give it a constant internal diameter, and
in a second stage, gets positioned along the conduit,
d) sectioning the structural element at each end of the conduit, after this structural element has been positioned.
The heating temperature preferably ranges from 130° C. to 160° C. and the drawing speed is preferably from 2 to 3 meters/minute.
REFERENCES:
patent: 4529009 (1985-07-01), Horner et al.
patent: 4804020 (1989-02-01), Bartholomew
patent: 4906496 (1990-03-01), Hosono
patent: 5069255 (1991-12-01), Muszynski
patent: 5433252 (1995-07-01), Wolf
patent: 5920032 (1999-07-01), Aeschbacher
patent: 6116290 (2000-09-01), Ohrn
patent: 2 730 101 (1989-02-01), None
Campion Jean-Luc
Le Cam Joel
Mignon Pierre
Boutsikaris Leo
France Telecom
Nilless & Nilles SC
Spyrou Cassandra
LandOfFree
Device for placing a structural element in a cable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for placing a structural element in a cable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for placing a structural element in a cable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2441311