Abstract:
A support device for supporting at least one electric harness where it passes through a through hole in a composite material structure, the structure presenting two faces into which the hole opens out, the device including a first element made of dielectric material presenting a first bearing surface designed to be applied against one of the faces of the structure and a sleeve having a first end secured to the first bearing surface and having outside dimensions that are smaller than those of the hole so as to be capable of being inserted therein, and a second element made of dielectric material presenting at least one second bearing surface suitable for being applied against the other face of the structure.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention provides a support device for supporting at least one electric harness where it passes through a through hole in a structure made of composite material, and it also provides a structure equipped with said support device. 
     The invention applies particularly, but not exclusively, to the field of designing and manufacturing aircraft or similar devices. 
     2. Description of the Related Art 
     The main structural elements of new aircraft, currently under development, are made of composite materials having very high electrical resistance (≈1000 times greater than aluminum) and low thermal conductivity (≈half that of aluminum), with the main result that any injection of current into a part of the composite material structure may lead to said part being greatly damaged. In addition, the high abrasive potential of certain composite materials increases the probability of such an event after prolonged contact between an electric cable and a part made of composite material. By way of example, the effects on such parts may be local heating that may lead to a fire, and loss of the mechanical characteristics of the structure (delamination, etc.). 
     Currently, when an electric harness passes through an opening provided in a composite panel or part, a fastening system is needed to hold the electric cable harness in the through hole so as to avoid any contact between an electric cable of the harness and the periphery of the through hole provided in the composite material structure. However, if the system for fastening the harness on the structure is lost, there is nothing to prevent the harness from making contact with the composite material of the structure, with the above-mentioned drawbacks. 
     A possible solution may consist in duplicating the fastening of the harness relative to the structure by means of two supports situated on either side of the through hole. However, that proposal is expensive, heavy and lengthy to implement when fastening the harness where it passes through structures. 
     Accompanying  FIG. 1  shows the problem to be solved.  FIG. 1  shows a structure  10  made of composite material that, in the example under consideration, is constituted by a cross-member of the IPN beam type  12 . This structure includes a vertical web  14  that presents two opposing faces  14   a  and  14   b . Through holes such as  16  and  18  are provided in the web  14  in order to enable electric cable harnesses  20  to pass through. In the known solution for ensuring that the harness  20  does not come into contact with the edge  18   a  of the orifice  18 , the harness is fastened to the structure, e.g. by a support  22  to which the periphery of the harness  20  is attached, e.g. by a collar  24 . The other end  22   a  of the fastening element  22  is fastened to the web  14  of the structure  12  by any suitable means. As explained above, it should be understood that in the event of the fastening part  22  breaking, there is a high risk of the harness coming into contact with the periphery  18   a  of the through hole  18 . 
     BRIEF SUMMARY OF THE INVENTION 
     A first object of the present invention is to provide a support device for supporting at least one electric harness where it passes through a through hole in a composite material structure, which device is simpler to implement than those described above while making it possible to increase safety, i.e. by very substantially reducing the risk of the composite material structure having its strength affected by contact with the harness. 
     To achieve this object, the invention provides a support device for supporting at least one electric harness where it passes through a through hole in a composite material structure, said structure presenting two faces into which said hole opens out, said device comprising a first element made of dielectric material presenting a first bearing surface designed to be applied against one of the faces of the structure and a sleeve having a first end secured to said first bearing surface and having outside dimensions that are smaller than those of said hole so as to be capable of being inserted therein, and a second element made of dielectric material presenting at least one second bearing surface suitable for being applied against the other face of the structure, said first and second elements being fastened together in the thickness of said sleeve by using at least one clip tab secured to one of said first and second elements and at least one clip notch provided in the other element. 
     Thus, the device of the present invention includes means for fastening together said first and second elements that are provided in the thickness of the sleeve and that comprise at least one clip tab secured to one of said first and second elements and at least one clip notch provided in the other element. 
     It should be understood that, after being assembled in the through hole, the first and second elements of the support device constitute a sort of ring made of dielectric material that completely covers the edge of the through hole in the composite material structure. Thus, even if the electric cable harness came into contact with said edge, the presence of the ring ensures that it makes no contact with the composite material constituting the structure. 
     It can also be seen that in view of its structure, assembling the protective ring in the through hole in the composite material structure is very simple since it merely requires the two elements of the support device to be clipped together. 
     It can be further understood that, by fastening the first and second elements together in the thickness of the sleeve, a clip tab projects from the sleeve, when said clip tab is secured to the first element, and a clip notch is provided in the thickness of the sleeve, when said clip notch is provided in the first element. As a result the device of the present invention can be assembled whatever the shape and dimensions of the hole in the structure, as long as the outside dimensions of the sleeve make it possible for said sleeve to be inserted in the hole. 
     For example, in non-limiting manner, it is thus possible to provide, a sleeve having outside dimensions that are adapted to those of the hole, and this makes it possible to position the device of the present invention in a manner that is stable relative to the structure. 
     Preferably, the first element is made as a single part. 
     Advantageously, said first and second elements are prevented from turning relative to the structure. 
     It should be understood that the support device can thus further include means for preventing turning of the first and second elements relative to the structure, the first and second elements being prevented from turning relative to the structure by using at least one member for preventing turning. 
     Advantageously, said first and second bearing surfaces have a shape that is circularly annular and said sleeve is circularly cylindrical. 
     Advantageously, at least one of said first and second elements presents a slot extending from its periphery, in such a manner as to be suitable for installation in situ when said electric harness is already installed. 
     Preferably, at least one of said first and second elements comprises at least one holder member configured to hold said electric harness relative to said first and second elements. 
     Thus, it should be understood that the support device further comprises holder means for holding the harness relative to the first and second elements. 
     Preferably, said first and second elements are made by molding, and said holder member is molded at the same time as said at least one of said first and second elements. 
     Thus, it should be understood that when the elements forming the protective ring are made by molding, the holder means are also made by molding at the same time as the element to which they are secured. 
     Advantageously, said holder member includes a support on which said electric harness is attached. 
     Thus, it should be understood that the holder means comprise a support and at least attachment means for attaching the harness to the support. 
     In a possibility provided by the invention, the clip tab is retractable. 
     Advantageously, the clip tab is equipped with clip catches and the clip notch is provided with locking catches. 
     Thus, it should be understood that fastening of the first and second element is performed by a number of clip catches of the clip tab co-operating with locking catches of the clip notch that depends on the thickness of the structure, in such a way that the device may thus be assembled on the structure whatever the thickness of said structure, as long as at least one clip catch of the clip tab is able to co-operate with at least one locking catch of the clip notch. Thus, as a result, the device of the present invention presents great modularity and may be more easily standardized so as to reduce manufacturing costs. 
     A second object of the present invention is to provide a composite material structure that is equipped with support means of the type mentioned above. 
     The composite material structure that is equipped with support means includes a through hole for an electric harness and two faces into which the through hole opens out and a support device of the type mentioned above in which the first and second elements are fastened together so that each bearing surface is applied against one of the faces of the structure. 
     Thus, according to the second object of the invention, the composite material structure, in which there is provided at least one through hole for an electric harness, presents two faces into which said hole opens out, and said structure includes at least one support device comprising a first element made of dielectric material presenting a first bearing surface designed to be applied against one of the faces of the structure and a sleeve having a first end secured to said first bearing surface and having outside dimensions that are smaller than those of said hole so as to be capable of being inserted therein, and a second element made of dielectric material presenting at least one second bearing surface suitable for being applied against the other face of the structure, said first and second elements being fastened together in the thickness of said sleeve by using at least one clip tab secured to one of said first and second elements and at least one clip notch provided in the other element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the invention can be better understood on reading the following description of several embodiments of the invention, given by way of non-limiting examples. The description makes reference to the accompanying figures, in which: 
         FIG. 1 , described above, is a perspective view of a cross-member having known holder means for holding the harness where it passes through an opening made in the structure; 
         FIG. 2  is a face view of the first element of the support device; 
         FIG. 3  is a face view of the second element of the support structure; 
         FIG. 4A  is a vertical section view showing the complete support device before being assembled on the composite material structure; 
         FIG. 4B  is a section view showing a variant of the support device shown in  FIG. 4A  that makes it possible to prevent the parts that make up the support device from turning; 
         FIG. 5  is a perspective view of a composite material structure that is equipped with the support device for supporting the electric cable harness where it passes through; 
         FIG. 6  is a face view showing a variant embodiment of the first and/or second element of the support structure; 
         FIG. 7A  is a vertical section view showing another embodiment of the complete support device before being assembled on the composite material structure; and 
         FIG. 7B  is a section view showing a variant of the another embodiment of the support device shown in  FIG. 7A  that makes it possible to prevent the parts that make up the support device from turning. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference firstly to FIGS.  2  to  4 A- 4 B and  7 A- 7 B, there follows a description of the essential elements of the support device for supporting the electric harness where it passes through a through hole in a structure. 
     The support device having the general reference  30  in  FIG. 4A  is constituted by a first element  32  and by a second element  34  that, when assembled together, constitute a protective ring for the harness. The first element  32  is constituted by a part  36  in the shape of a circular ring that, by means of its rear face  36   a , defines a first bearing surface. Naturally, the shape of the support device is closely linked with the shape of the opening made in the structure  12 . 
     This first element  32  further comprises a sleeve  38  that projects from the face  36   a  of the annular part  36 . The outside diameter D 1  of the element  32  is naturally larger than the diameter of the opening  18 . The inside diameter D 2  of the sleeve  38 , and thus of the element  32  as a whole, is smaller than the diameter of the opening  18 . Finally, the outside diameter D 3  of the sleeve  38  is smaller than the diameter of the through hole  18 , so that the sleeve  38  may be inserted in the opening  18 . 
     The second element  34  of the support device  30  is constituted by a part  35  of circular ring shape having an outside diameter D′ 1  that is preferably equal to the outside diameter D 1  of the element  32  and having an inside diameter D′ 2  that is substantially equal to the inside diameter D 2  of the sleeve  38 . 
     In order to make the protective ring, it is naturally necessary to fasten the elements  32  and  34  together after they have been put into place in the through hole  18 . Preferably, the means for fastening the elements  32  and  34  together are made up firstly of clip tabs having references  42 ,  44  that are regularly spaced apart around the periphery of the element  34  and that project from the rear face  35   a  of the part  35  forming the element  34 . These clip tabs are preferably equipped with clip catches. In order to co-operate with the clip tabs  42 ,  44 , blind openings  48  to  54  are provided in the thickness of the sleeve  38 , which openings are of shapes that are complementary to the clip tabs  42 ,  44 , and so they are therefore also provided with locking catches. 
     Advantageously, the clip tabs  42 ,  44  are retractable with a simple tool, e.g. of the unlocking fork type, so as to enable the elements  32  and/or  34  to be replaced. Provision may also be made for weakening at least one of said clip tabs  42 ,  44 , e.g. by means of an indentation or the like, making it possible for the clip tab  42 ,  44  to break at its base, or in a desired zone, when subjected to a force that is greater than the strength of the tab as weakened in this way, and acting parallel to the plane of the second bearing surface  35   a  or perpendicular to the linear axis of the tabs  42 ,  44 . 
     In addition, it is very desirable for the protective ring constituted by the assembled-together elements  32  and  34  to be prevented from turning in order to avoid friction phenomena if the electric harness accidentally comes into contact with said ring. To do this, the annular parts  36  and  35  of the elements  32  and  34  are preferably provided with respective orifices  64  and  66  that face an orifice  68  provided in the structure through which the electric harness passes. It then suffices to engage a screw or any suitable means in order to ensure that turning is prevented. A variant of this proposal of preventing turning may consist in substituting a positioning peg  80  for the orifices  64  and  66 , which peg is integrated directly on the element  32  and/or  34  and is received in the orifice  68 . In the example of  FIG. 4B , the positioning peg  80  is present on the annular part  36  and is received in the orifice  68 . In this way, the annular part  36  is fastened to the web  14  of the structure  12  and is prevented from turning relative to the web  14 ; once the annular part  35  is fastened to the part  36 , the support device  30 , constituted by the two elements  32  and  34 , is prevented from turning on the structure  12 . In complementary manner, a positioning peg may also be provided in the same manner on the annular part  35  for being received in the same orifice  38 , it being understood that this solution is not essential for preventing said part  35  from turning because said clip tabs  42 ,  44  hold said part  35  and the annular part  36  together. 
     Preferably, and as can be better seen in  FIG. 4A  or  4 B, the annular elements  35  and  36  have respective rounded portions  70  and  72  in such a manner as to reduce the possibly abrasive effect of the ring constituted by the elements  32  and  34 , should the harness come into contact with said ring. 
     In the description given above, the through holes  18  under consideration are circular in shape. Naturally, it would not go beyond the ambit of the invention if the through holes were of a different shape, in particular of an oval or oblong shape for example, in order to enable two or more electric harnesses to pass through a single through hole. Naturally, the elements  32  and  34  would then need to be adapted to said different shape by providing oval or oblong shapes also for the annular plates  35  and  36  and for the sleeve  38 . 
     Naturally, the elements  32  and  34  need to be made of a material that presents very high dielectric coefficient in order to ensure electrical insulation between the harness and the structure through which it passes, in the event of the harness coming into contact with the periphery  18   a  of the through hole  18 , and also presenting a low abrasive potential in order to avoid damaging the cables in the event of prolonged contact. 
       FIG. 5  shows an example of assembling a support device of the invention. The elements  32  and  34  are presented on opposite sides of the support structure and they are clipped on to it by means of the clip tabs and clip orifices. The screw for preventing turning of the resulting protective ring is put into place. Preferably, the support device further comprises means for fastening the harness  20  to the protective ring constituted by the elements  32  and  34 . To do this, it is possible to provide a fastening tab  60  having one end  60   a  fastened to the periphery of the harness  20 , e.g. by means of a clamping collar  62 , and having its other end  60  fastened to one of the parts  32  or  34  constituting the protective ring. 
     As explained above, even if the fastening means  60  break accidentally, any potential contact between the electric harness and the protective ring runs no risk of harming the mechanical properties of the composite material forming the structure  12 . 
     As can be seen in  FIGS. 2 and 3  in particular, the elements  32  and  34  may present a slot  92 ,  94  extending radially at a single location of their periphery, and preferably at a top portion when the elements  32 ,  34  are installed in situ. The slot  92 ,  94  makes it possible, by bending the two ends, to engage said parts  32  and  34  on an already-installed harness without any risk of the harness being damaged and without any need to remove it. The selected material needs to be suitably flexible to enable said bending to be performed without risk of breaking. 
     The clip tabs  42 ,  44  should be retractable by means of a tool (an unlocking fork) in order to enable the elements  32  and  34  to be taken apart and replaced, where necessary (e.g. if they become damaged). 
     A variant embodiment of the element  32  or  34  is shown in  FIG. 6 . In this embodiment, the annular portion  35  or  36  respectively of the parts  34  or  32  includes holder means  81  designed for positioning the harness  20 . The holder means  81  include a support-forming top portion  82  advantageously presenting a shape that is adapted to positioning the harness  20  centrally. In the example selected to illustrate the invention, the support  82  of the holder means  81  presents a V-shaped section that is substantially flat. The harness  20  can thus be positioned on the support  82  by being wedged in the V-shaped portion that, preferably, coincides with the middle axis X′X of the element  32  or  34 . In addition, in order to hold the harness  20  firmly on the holder means  81 , a tie, e.g. of the “Tyrap” type, surrounds the harness  20  in order to hold it or retain it against the holder means  81 . This tie  83 , possibly a plurality of ties, is fastened by its two ends to the end portions  84 ,  85  of the support  82  of the holder means  81 , by conventional means such as by adhesive or by inserting/blocking the ends of the tie  83  in respective slots provided in the two opposite ends  84 ,  85  of the support  82  of the holder means  81 . 
     Naturally, the holder means  81  may present other shapes, and may for example comprise a tube or ring in which the harness  20  can be inserted and fastened. In addition, the symmetrical disposition on a mid-plane X′X is absolutely not necessary, in particular because the harness  20  is subsequently fastened to the holder means  81 .