WO2012160411A1

WO2012160411A1 - Ultralight cable sheath for screening electrical and magnetic fields

Info

Publication number: WO2012160411A1
Application number: PCT/IB2011/052220
Authority: WO
Inventors: Mauro Maggioni
Original assignee: Lamiflex S.P.A.
Priority date: 2011-05-20
Filing date: 2011-05-20
Publication date: 2012-11-29
Also published as: EP2710696A1

Abstract

An ultralight cable conduit for shielding electrical and magnetic fields, comprising an inner tubular element (1) made of composite material, which supports an outer sheet-like layer (10) which provides an outer tubular element made of electrically conducting material, the outer tubular element (10) being jointly connected to the inner tubular element (1) during the polymerization of the composite material.

Description

ULTRALIGHT CABLE SHEATH FOR SCREENING ELECTRICAL AND MAGNETIC FIELDS

Technical Field

The present invention relates to an ultralight cable conduit for shielding electrical and magnetic fields.

Background Art

As is known, electronic instruments are becoming increasingly widespread and this has made critical the need to adequately screen all cables that can create interference or disturbances in electronic apparatuses.

In particular considering, solely for the purposes of example, the field of aviation, it is also necessary that adequate screening be combined with a reduction in the weight of the screening, since the weight problem is a very important factor in the specific field of application.

The solutions currently used are generally based on the use of metal conduits that are rigid, heavy and subject to considerable damage.

US 563045 devised an improvement to the field, by introducing a screening conduit especially made for aircrafts which is flexible and low weight and made with a tubular core that is deformable and flexible and which has helical corrugations on the outer surface upon which a conventional metalized fabric is applied, which is helically wrapped around the corrugations and is fixed by means of wires or strips wrapped around the fabric which, in practice, is made with a coiled ribbon.

This embodiment is structurally complex and suffers the typical drawbacks that derive from the use of ribbon, owing to the number of points of contact between the several coils of the ribbon.

Disclosure of the invention

The aim of the present invention is to solve the above mentioned drawbacks, by providing an ultralight cable conduit for shielding electrical and magnetic fields which is obtained only with two component elements that can have any shape in section in order to adapt to different applications. Within this aim, an object of the invention is to provide a conduit that, in addition to being flexible, can be obtained with any cross-section, thus improving the surface conductibility of the screening element placed on the outer surface.

Another object of the present invention is to provide a cable conduit that, thanks to its distinctive implementation features, is capable of offering the widest guarantees of reliability and safety in use.

A further object of the present invention is to provide a cable conduit that can be easily implemented using elements and materials that are readily available on the market, and which, moreover, is competitive from a merely economical viewpoint.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by an ultralight cable conduit for shielding electrical and magnetic fields, according to the invention, characterized in that it comprises an inner tubular element made of composite material which supports an outer sheet-like layer which provides an outer tubular element made of electrically conducting material, said outer tubular element being jointly connected to said inner tubular element during the polymerization of said composite material.

Brief description of the drawings

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of an ultralight cable conduit for shielding electrical and magnetic fields, which is illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is an exploded perspective view of the conduit, according to the invention;

Figure 2 is a perspective view of two segments of conduit which can be mutually coupled with a spigot joint;

Figure 3 is a sectional view of two segments of conduit with spigot joint, separated one another;

Figure 4 is a sectional view of a conduit with spigot joint with the elements mutually coupled;

Figure 5 is a perspective view of two segments of conduit with a flange joint;

Figure 6 is a view of two segments of conduit with flange joint, separated one another;

Figure 7 is a sectional view of two segments of conduit with flange joint, mutually coupled.

Ways of carrying out the invention

With reference to the figures, the ultralight cable conduit for shielding electrical and magnetic fields, according to the invention, comprises an inner tubular element, generally designated with the reference numeral 1, which, according to a preferred but not binding embodiment, is constituted by a composite material that is obtained by means of a coiled continuous ribbon of a glass fabric impregnated with epoxy resin.

The use of a coiling in composite material makes it possible to optimize the number of layers with the possibility, by varying the number of layers, of modifying, according to the contingent needs, the characteristics of deformability, practically by working on the rigidity of the cross-section.

On the inner tubular element an outer tubular element 10 is applied that is constituted by a sheet-like layer made of electrically conducting material, advantageously made of a fabric made of polyester treated with nickel.

So the result has the mechanical characteristics and lightness of polyester, but the conductive behavior of a metal.

In particular the use of nickel instead of copper ensures certainty of the stability over time of the metalization, without problems of corrosion and/or oxidation of the conductive layer proper.

From a design point of view it is optimal to provide the conduit in modular segments with the possibility of being mutually joined together, so as to obtain the desired extension in terms of length of the conduit.

To this end, as illustrated in Figures 2 to 4, at the ends of each segment of inner tubular element 1 a spigot joint is provided which is constituted by a male portion 5 and by a female portion 6 which are made of polyester like the composite material, so as to provide the classic spigot coupling.

In the specific embodiment, the outer tubular element is positioned outside the male part of the joint, while it is positioned inside the female part of the j oint.

Interposed between the two is a ribbon with annular surface filaments 7 which is made of conductive material, obtaining thereby a metalization coupling with the same chemical nature, considerable ease of assembly since in practice a mechanical coupling is made, and low cost thanks to the compatibility of gluing between the conduit and the portion with the annular filaments during polymerization which provides the stabilization of the layer of composite material and its stable joining to the outer tubular element.

The increase in thickness due to the presence of the ribbon with annular filaments 7 is compensated for by the socket widening of the female part, thus maintaining the electrical contact on the screening portion.

In the joining step, the widening of the cross-section of the female part of the joint is less than the nominal thickness of the male part affected by the ribbon with annular filaments 7, since in the coupling the portion with the annular filaments undergoes a compression with mechanical interference and without deformation of the cross-section of the conduit of the joint.

Such interference enables the joint to remain in position even if subjected to the operating vibrations of the apparatus on which it is installed, and moreover it enables a friction of the joint proper that does not involve excessive shearing stresses which could damage the metallic covering of the conductive fabric and of the ribbon with annular filaments, thus ensuring better stability of the metalization over time.

According to what is shown in Figures 5 to 7, a flange joint is provided with a flanged end portion 11 for each segment, on the contact face thereof a layer of conductive felt 12 being applied which enables the joint to create the deformations that make it possible for the joint to have a contact over all the surface of the flange thus ensuring a high electromagnetic seal.

This embodiment is particularly adapted when it is necessary to cross a bulkhead or earth the conduit on the structure of the machine on which it is installed.

The use of felt 12 with nickel metalization makes it possible to have an optimal chemical compatibility between the metalized elements and chemical compatibility between the elements that constitute a structure of the conduit proper, and with great ease of outcome during the polymerization cycle in an autoclave in order to obtain the connection of the flange to the inner tubular element.

From the foregoing it can be seen that the invention achieves the intended aim and objects and in particular attention is drawn to the fact that an ultralight cable conduit for screening electrical and magnetic fields is provided, in which, by exploiting the coupling of two materials and specifically of a stratified composite material in order to provide the inner tubular element and of a metalized layer for the outer tubular element, it is possible to obtain conduits with high shielding, with very low weight and with the advantage of considerable modularity of the assembly.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided that they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements.

Where the technical features mentioned in any claim are followed by reference numerals and/or signs, those reference numerals and/or signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals and/or signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference numerals and/or signs.

Claims

1. An ultralight cable conduit for shielding electrical and magnetic fields, characterized in that it comprises an inner tubular element (1) made of composite material, which supports an outer sheet-like layer (10) which provides an outer tubular element made of electrically conducting material, said outer tubular element (10) being jointly connected to said inner tubular element (1) during the polymerization of said composite material.

2. The conduit according to claim 1, characterized in that said inner tubular element (1) is constituted by a continuous ribbon of glass-based fabric impregnated with epoxy resin.

3. The conduit according to the preceding claims, characterized in that said continuous ribbon is arranged substantially in a spiral.

4. The conduit according to one or more of the preceding claims, characterized in that said composite ribbon is constituted by a plurality of layers which can vary according to the deformability characteristics that are required.

5. The conduit according to one or more of the preceding claims, characterized in that said sheet-like layer made of electrically conducting material (10) is constituted by a fabric made of polyester treated with nickel.

6. The conduit according to one or more of the preceding claims, characterized in that it is provided in segments, with end joints (5, 6 and 1 1) for their mutual connection.

7. The conduit according to one or more of the preceding claims, characterized in that said joints comprise a spigot joint constituted by a male portion (5) and a female portion (6), which are connected to said composite ribbon (1), on said male portion (5) a ribbon with annular surface filaments (7) made of conducting material being provided, said ribbon with annular filaments being adapted to engage the outer surface of said female portion (6) covered internally by said outer tubular element (10).

8. The conduit according to one or more of the preceding claims, characterized in that said joints comprise flange-like end portions (1 1), on whose face directed toward the adjacent segment a layer of electrically conducting felt (12) is provided.