Patent Document

The present invention concerns a fixing device for wire cable trays. 
     BACKGROUND OF THE INVENTION 
     In the manner known in the art, wire cable trays take the form of a channel consisting of wire mesh. This mesh includes longitudinal wires, usually called warp wires, and transverse wires called weft wires. The warp wires are rectilinear, or substantially rectilinear, and are welded to the weft wires. The latter generally have an overall U-shape and are disposed with a regular pitch along the warp wires. Thus, overall, a cable tray includes three panels, namely a bottom panel and two lateral panels. 
     Such cable trays are commonly used to accommodate, support and protect flexible conduits of diverse kinds: electrical cables (low-voltage or high-voltage), data transmission cables (telephone, optical fiber, etc.), fluid pipes, etc. 
     It is sometimes required to group cables together in a cable tray to form a bundle of cables in the cable tray and to fix this bundle into the cable tray. A cable tie is then used, for example, which surrounds the cables concerned and a warp wire of the cable tray. 
     It can also be required to fix an accessory in the cable tray. The classic solution is then to bolt it into the bottom of the cable tray or to a lateral flange. 
     SUMMARY OF THE INVENTION 
     The present invention has the object of providing a device for fixing elements—cable bundle, accessory, sundry objects, etc.—into a cable tray. This device can preferably on the one hand be fitted to numerous types of cable tray and on the other hand be mounted quickly, without ancillary parts (bolts, etc.) and without tools. This device can advantageously also be fitted on site as required. 
     To this end, the invention proposes a fixing device for wire cable trays including on the one hand longitudinal warp wires and on the other hand transverse weft wires, having a base with a mounting face by which it is mounted on the cable tray and fixing means. 
     According to the invention, this fixing device includes:
         at least one trough-shaped longitudinal housing intended to receive a first wire of the cable tray (warp wire or weft wire) and produced in the mounting face,   at least one bearing surface undercut relative to the mounting face, said surface extending perpendicularly to the longitudinal housing and being disposed parallel to the back of the longitudinal housing at an intermediate level between the back of that housing and the mounting face, and   at least one transverse cut-out corresponding to each intersection between a longitudinal housing and a bearing surface, this cut-out extending from one edge of the mounting face to a longitudinal housing.       

     This device can easily be fitted, without tools, to a cable tray. A first wire of the cable tray (warp wire or weft wire) bears on the bottom of the trough-shaped housing while a second wire of the cable tray (weft wire or warp wire) bears on the bearing surface, thereby retaining the device with a clamping force depending on the distance between the bottom of the trough and the bearing surface. Here mounting is effected by bearing on two faces (edges) of wires of the cable tray that are welded together. Thus the diameter of the wires used is of no consequence. 
     In a first embodiment, a fixing device of the invention has a plurality of similar longitudinal housings disposed parallel to each other at a regular pitch. 
     In a second embodiment, a fixing device of the invention includes a plurality of similar transverse cut-outs disposed parallel to each other at a regular pitch. 
     By adapting to the shapes in which cable trays are produced, these two embodiments offer improved retention to enable the fixing of an accessory on which a greater or lesser load is exerted. 
     When there are both a number of longitudinal housings and a number of transverse cut-outs, the pitch between the longitudinal housings is preferably the same as that between the transverse cut-outs. The fixing device can then be mounted in two different mutually perpendicular orientations on the cable tray. 
     For improved retention on the cable tray on which the device of the invention is mounted, a boss can be produced on the bearing surface. Fitting is then effected by clipping. 
     In one embodiment of the device of the invention the base is produced in a molded synthetic material. In this case, this fixing device is associated for example with a cable retaining device. One such cable retaining device is described in U.S. Pat. No. 7,107,653, for example. 
     In another embodiment the base of the device of the invention is produced in sheet metal cut and bent to shape. The fixing means of this device then take the form of circular bores and/or oblong holes produced in the sheet. 
     The present invention also concerns an embodiment of a fixing device including a single trough-shaped longitudinal housing, a single transverse cut-out and two bearing surfaces disposed on opposite sides of the longitudinal housing. This particularly advantageous embodiment places the device at the intersection of a warp wire and a weft wire. 
     Finally, the present invention also concerns an assembly including on the one hand a section of cable tray having longitudinal warp wires and U-shaped transverse weft wires and on the other hand a fixing device as described above, this assembly being characterized in that the base of the fixing device is inside the section of cable tray, that is to say between the branches of the U-shape of the weft wires, and in that each longitudinal housing receives a warp wire. In this advantageous embodiment, the fixing device is mounted by positioning said device in the cable tray and sliding it along a warp wire. This is advantageous because if cables have already been placed in the section of cable tray, the movement to fix the fixing device is parallel to the cables already in place and can therefore be performed easily. Movements when fixing a cable tray to a support or the like generally entail sliding along a weft wire and thus in a direction perpendicular to any cables in the cable tray. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Details and advantages of the present invention will emerge more clearly from the following description, given with reference to the appended diagrammatic drawings, in which: 
         FIG. 1  represents diagrammatically a fixing device of the invention mounted in a wire cable tray, 
         FIG. 2  is a view of the fixing device from  FIG. 1  in cross section, 
         FIG. 3  is a view in longitudinal section on the section plane III-III in  FIG. 2  during mounting of the fixing device on the cable tray, 
         FIG. 4  is a view from below corresponding to the mounting step from  FIG. 3 , 
         FIG. 5  is a perspective view of a different embodiment of a fixing device mounted in a wire cable tray, 
         FIG. 6  is a view in section taken along the line VI-VI in  FIG. 5 , 
         FIG. 7  is a perspective view showing two fixing devices of another embodiment mounted in a cable tray, and 
         FIG. 8  is a perspective view from below of another embodiment of a fixing device of the invention mounted in a wire cable tray. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 to 4  represent a first embodiment of a fixing device of the invention. This device includes on the one hand a base  2  and a cable retaining device  4 . It is produced in one piece, for example by molding a synthetic material. 
     The base  2  is intended to enable fixing of the fixing device of the invention to a section of wire cable tray  6 . In the conventional way, and as represented in the drawings, this cable tray is gutter-shaped and includes longitudinal wires  8  called warp wires and transverse wires  10  called weft wires. The warp wires  8  are rectilinear (except for the edge wires in the embodiment represented, which are nevertheless substantially rectilinear). The weft wires  10  are U-shaped. The section of cable tray  6  therefore has a bottom panel  12  and two lateral panels  14 . It is assumed here that the bottom panel  12  is at the bottom of the lateral panels. This bottom panel  12  is disposed in a substantially horizontal plane whereas the lateral panels  14  extend substantially vertically. Such an orientation is usual for a section of cable tray. Other orientations can nevertheless be envisaged, for example with the bottom panel  12  disposed vertically or inclined. 
     The base  2  has a mounting face  16  which, in a preferred embodiment, is a substantially plane face. A trough-shaped housing  18  is produced in the mounting face  16 . This housing  18  forms a groove extending the entire length of the mounting face  16  intended to receive a wire of the section of cable tray, a warp wire  8  in the orientation chosen for  FIGS. 1 to 4 . Here this housing  18  is considered to extend longitudinally. There is thus defined an orientation that corresponds to the orientation of the section of cable tray  6  represented, but as will emerge hereinafter, the fixing device of the invention can equally be fixed to the section of cable tray  6  oriented so that the housing  18  extends transversely relative to said section. 
       FIGS. 1 and 2  show the trough shape of the housing  18 . The back of this housing, which in the chosen orientation is at the top of the housing  18 , preferably has a radius of curvature adapted to the diameters of the wires intended to be placed in the housing  18 . If warp or weft wires with different diameters are to be housed in the housing  18 , the latter will preferably have a radius of curvature corresponding to the larger wire radius. The housing  18  having another shape can nevertheless be envisaged: it could be V-shaped, for example, or some other shape. 
     The base  2  also has a bearing surface  20  set back relative to the mounting face  16 . This bearing surface  20  extends perpendicularly to the housing  18 . It is parallel to the back line  22  of the housing  18 . In the embodiment shown here, which is a preferred embodiment, it is also parallel to the mounting face  16 . 
     The bearing surface  20  is between the mounting face  16  and the back line  22  of the housing  18 . The distance between the bearing surface  20  and the back line  22  (which is parallel to it) is a few tenths of a millimeter. 
     A transverse cut-out  24  provides access from the mounting face  16  to the bearing surface  20 . This cut-out is seen in  FIG. 3  in particular. The bearing surface  20  being intended to serve as a support for a wire of the cable tray on which the fixing device is mounted, the transverse cut-out  24  enables that wire to pass from the mounting face  16  to the bearing surface  20 . Thus this transverse cut-out  24  opens into the mounting face  16 . In the embodiment represented in  FIGS. 1 to 4 , the transverse cut-out  24  forms with the housing  18  a cross. This transverse cut-out  24  extends either side of the longitudinal housing  18  to the corresponding edge of the mounting face  16  of the base. 
     As  FIG. 3  shows, this transverse cut-out  24  is L-shaped. One branch of this L-shape is perpendicular to the mounting face  16  while the other branch of this L-shape is parallel to the bearing surface  20 . Accordingly, in order to bear on the surface  20 , a wire of the cable tray, a weft wire  10  in  FIGS. 1 to 4 , is first placed parallel to the mounting face  16  and perpendicular to the longitudinal housing  18 . This weft wire  10  then penetrates through the transverse cut-out  24  in the base  2 , after which it is slid parallel to the mounting face  16 , parallel to the bearing surface  20 , to take up a position on this undercut bearing surface  20 . 
     Arrows in  FIG. 3  show the mounting of the fixing device on the section of cable tray  6 . Thus the base  2  is first positioned at an intersection between a warp wire  8  and a weft wire  10  so that the cross formed by the housing  18  and the transverse cut-out  24  coincides with the intersection of the wires of the cable tray where the fixing device is to be placed ( FIG. 4 ). In the situation represented, the longitudinal housing  18  faces a warp wire  8  while the transverse cut-out  24  faces a weft wire  10 . 
     The base  2  is then moved vertically downward (in the chosen orientation, see above) indicated by the first arrow  26  in  FIG. 3 . The warp wire  8  then comes to rest on the back of the longitudinal housing  18  ( FIG. 3  position). The base  2  is finally pushed in the longitudinal direction, as indicated by the second arrow in  FIG. 3 . The weft wire  10  then slides on the bearing surface  20 , for example until it abuts on the back of the cut-out, as shown in  FIG. 1 . This movement is guided by the warp wire  8  sliding in its housing  18 . 
     The fixing device of the invention, once mounted, is retained on the one hand by the back of the housing  18  bearing on the warp wire  8  and on the other hand by the weft wire  10  bearing on the bearing surfaces  20 . There can be a slight clamping effect here to retain the device of the invention on the section of cable tray  6  by adapting the distance between the back line  22  of the housing  18  and the bearing surfaces  20 . This device is then retained thanks to this clamping effect without having to use any tools. Moreover, if cables (not shown) are present in the section of cable tray  6 , mounting can be effected anyway because, during mounting, fixing is effected by a longitudinal movement, which is parallel to the cables. Because of this, the cables do not greatly impede the fixing of the device. 
     In the embodiment of  FIGS. 1 to 4 , the base  2  is produced in a synthetic material having relatively high elasticity (compared to sheet metal). A boss  30  is then provided for improved retention of the fixing device (or its base  2 ) to the section of cable tray  6 . This boss  30  is produced near the edge of the bearing surface  20  on the same side as the transverse cut-out  24 . It is positioned to leave sufficient room between it and the back of the transverse cut-out  24  to accommodate the wires of greater diameter intended to bear on the bearing surfaces  20 . 
     The cable retaining device  4  is shown diagrammatically in  FIGS. 1 to 4  as a ring. This ring is preferably covered, but this opening enabling introduction of cables is not represented in the drawings. This is a retaining device like that described in U.S. Pat. No. 7,107,653, for example. Such a device enables rapid placement of cables to retain them. This retention is furthermore reversible. The device can thus be opened and closed at will to add or remove a cable. 
       FIGS. 5 and 6  show another embodiment of a fixing device of the invention. This embodiment is in sheet metal. For this and subsequent embodiments, elements similar to those of the first embodiment of  FIGS. 1 to 4  have the same references as in those figures. 
     On the device of  FIGS. 5 and 6 , there is a mounting face  16  with two longitudinal housings  18  and a transverse cut-out  24  for each of the housings  18 . The mounting face  16  is the lower face of the fixing device and is not visible in  FIG. 5 . The device is produced from sheet metal by cutting and pressing. Thus the formation of the housings  18  in the mounting face  16  produces a rib on the face of the sheet opposite the housings  18 . 
     The two transverse cut-outs  24  extend in each case from a longitudinal housing  18  to an edge of the mounting face  16 . They are aligned and thus correspond to the same weft wire  10  (or warp wire  8 ). Each transverse cut-out  24  here defines a tongue  32  one face of which, that opposite the mounting face  16 , is part of the bearing surface  20 . 
     To enable the fixing of any accessory, the fixing device includes fixing means which, in the embodiment shown (see  FIG. 5 ), are two bores  34  of circular shape. 
     To mount this fixing device on the section of cable tray  6  as shown in  FIG. 5 , the mounting face  16  is placed on the bottom panel  12  of the section of cable tray  6  so that the longitudinal housings  18  face two warp wires  8 . The fixing device is introduced via the interior of the section of cable tray (the interior corresponding to the space between the branches of the U-shape of the cable tray) and the concave face of the housings  18  is oriented toward the exterior of the section of cable tray. A weft wire  10  is level with the transverse cut-outs  24 , more particularly where the transverse cut-outs open into the mounting face  16 . The warp wires  8  then take their place in the housings  18 . The fixing device is then slid longitudinally so that the weft wire  10  passes over the tongues  32  and thus comes to bear on the corresponding bearing surface  20 . This latter movement is guided by the warp wires  8  sliding in the longitudinal housings  18 . 
     In this sheet metal embodiment, having only one longitudinal housing  18  and only one transverse cut-out  24  can be envisaged. There are then two bearing surfaces  20  disposed on opposite sides of the longitudinal housing  18 . Thus the device can be mounted at the crossover of a warp wire and a weft wire of the section of cable tray. 
       FIG. 7  shows another embodiment of a fixing device of the invention. Two identical fixing devices are represented in this figure. This figure shows how the same fixing device of the invention can be fixed with two different orientations, either inside a section of cable tray  6  or outside it. 
     The fixing device represented here is also produced in sheet metal. It includes a base  2  having a mounting face  16  and a fixing plate  36 . This fixing device is also produced by pressing and bending sheet metal. The fixing plate  36  is provided with bores  38  of circular shape and oblong holes  38 ′. 
     The mounting face  16  of this fixing device includes a longitudinal housing  18  and six transverse cut-outs  24 . The transverse cut-outs  24  are regularly spaced with a regular pitch, for example a pitch of 50 mm. This pitch corresponds to the pitch between two adjacent warp wires. The pitch between two weft wires is twice that between the warp wires, i.e. 100 mm. These numerical values are given by way of nonlimiting example, but correspond to values currently found on some cable trays. The fact of having warp wires and weft wires with separation pitches of which one is a multiple of the other enables mounting of the fixing device in the two positions shown in  FIG. 7 . In one mounting position, the longitudinal housing  18  receives a weft wire  10 , whereas in the other mounting position it receives a warp wire  8 . In the first mounting the fixing device is mounted on a weft wire and six warp wires whereas in the second mounting position the fixing device is mounted on one warp wire and three weft wires. 
     This mounting in two different directions is illustrated by the embodiment represented in  FIG. 7 , but it is clear that the other embodiments described above, and many other embodiments of the invention, also enable such mountings on the same cable tray. 
       FIG. 8  shows by way of illustration another embodiment in sheet metal. The fixing device of this embodiment includes three longitudinal housings  18  and is intended to be mounted on two weft wires and six warp wires or three warp wires and three weft wires. 
     Of course, embodiments with a plurality of longitudinal housings  18  and/or a plurality of transverse cut-outs  24  can be produced for bases of synthetic material fixing devices of the type shown in  FIGS. 1 to 4 . 
     The fixing devices described above can be considered as universal fixing devices because each can be used on cable trays produced with wires of different diameters: they can be used on a cable tray using wires of different diameters, but they can also be used on two different cable trays produced with wires of different diameters. Furthermore, fixing devices whose mounting face includes a longitudinal housing and a transverse cut-out can adapt to any intersection of two wires of a cable tray and can be mounted at will essentially inside the cable tray or outside it. A device of the invention thus enables fixing of an accessory intended to be located inside a cable tray or outside it. 
     Note further that the mounting of these devices is easy and can be effected without tools. These sections can be mounted on demand on site when fitting a cable tray with no auxiliary parts, such as bolts or the like. 
     Even if a device of the invention can be produced in bent and cut sheet metal, it is a device offering good accuracy and high stiffness. A molded synthetic material embodiment also provides good accuracy. It has the advantage of not being aggressive to cables intended to be placed in the cable tray. 
     The devices described are essentially intended to be mounted in a section of cable tray but mounting versions with a plurality of longitudinal housings and/or a plurality of transverse cut-outs between two sections of cable tray can also be envisaged. 
     The present invention is not limited to the embodiments described above by way of nonlimiting example and to the variants referred to. It concerns equally all variants evident to the person skilled in the art within the scope of the following claims.

Technology Category: 4