Abstract:
A connecting butt strap connecting in series two wire cable trays ( 10, 20 ) consisting of two different types of wires, warp wires and weft wires, the connection of the two cable trays ( 10, 20 ) being produced via their abutted weft wires ( 12, 22 ): it comprises two clip-on elements adapted to clip the butt strap ( 30 ) on each of the abutted weft wires ( 12, 22 ), one of which enables the butt strap to be mounted rotatable ( 30 ) on one cable tray ( 10 ) and the other enables the two cable trays ( 10, 20 ) to be assembled, the butt strap ( 30 ) further comprising locking elements adapted to co-operate with a warp wire of the other cable tray ( 20 ) and to lock the butt strap ( 30 ) in its connecting position.

Description:
BACKGROUND OF THE INVENTION 
   The present invention is generally concerned with wire cable trays. 
   As the person skilled in the art knows, wire cable trays comprise a mesh formed of wires of two different types, namely longitudinal wires, usually referred to as warp wires, which run longitudinally and in a rectilinear or quasi-rectilinear manner over the whole of their length, and, from place to place along these longitudinal wires, and appropriately attached thereto, transverse U-shaped wires, usually referred to as weft wires, the combination globally forming three panels which are in practice plane or substantially plane, namely a bottom panel and two lateral panels. 
   Wire cable trays of the above kind are routinely used in the manner of troughs to support, house and protect electrical or similar cables. 
   By “electrical cables” is meant here, and hereinafter, not only cables adapted to transport and distribute electrical power, but also cables and fibers adapted to transmit information electrically, optically or otherwise. 
   With regard to electrical cables, wire cable trays have many advantages that are appreciated by electrical installers, and in particular the advantages of easy installation, and therefore economy, flexibility, since the electrical cables can be brought out through any of their meshes, transparency, and thus of easy identification of the electrical cables, ventilation, cleanliness, safety, both for the electrical cable and for users, and performance. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to propose a connecting butt strap for connecting two of the above wire cable trays very quickly, without using screws or nuts and bolts, said connecting butt strap not being liable to cause any damage and being adapted to be premounted on one of the cable trays and even recovered after use. 
   According to the invention, a connecting butt strap for butt jointing two wire cable trays consisting of wires of two different types, namely warp wires and weft wires, said cable trays being connected by means of their end weft wires, is characterized in that it includes two clipping arrangements adapted to clip said connecting butt strap to each of said end weft wires, one of which arrangements allows the connecting butt strap to be rotatably mounted on a cable tray and the other of which arrangements allows the two cable trays to be assembled, said connecting butt strap further including locking means adapted to cooperate with a warp wire of the other cable tray and to lock said connecting butt strap in its connecting position. 
   The connecting butt strap advantageously includes a U-shaped body having two flanges and a core, the clipping arrangements being defined between the lateral edges of a clipping rim extending the core and lying generally perpendicular thereto and each of said flanges; the core of the U-shaped body has a clipping rim at each end; one flange of the U-shaped body has at its end near a clipping rim a slot defining a tongue adapted to be bent toward the interior of the U-shape of the U-shaped body. 
   One flange of the U-shape of the U-shaped body is preferably extended by a locking rim carrying a locking lug adapted to be bent over a warp wire to lock the connecting butt strap in a connecting position; the locking lug is carried by the locking rim in line with the edge of a groove in said locking rim; the locking rim is generally parallel to the core of the U-shape of the U-shaped body. 
   The groove is advantageously parallel to the clipping rim. 
   The connecting butt strap preferably includes a notch in the core and the flanges of the U-shape body and extending the groove. 
   Said lateral edges of the rim advantageously have, in the vicinity of their end, a protuberance preceded by an entry bevel, said protuberance defining with the flanges of the U-shaped body a passage whose width is less than the diameter of the weft wires. 
   The invention also provides a set of two wire cable trays connected by at least one of the above connecting butt straps; the connecting butt strap is clipped on either side of the clipping rim by the facing wings of the end weft wires of the two cable trays, the tongues being bent over said wings, a warp wire of one cable tray lying in the groove and the notch, and the locking lug being bent over said warp wire. 
   The invention further provides a wire cable tray fitted with at least one of the above connecting butt straps, said connecting butt strap being mounted to pivot about a wing of an end weft wire and lying inside the cable tray along its lateral panel defined in particular by said wing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     To explain further the subject matter of the invention, embodiments of the invention shown in the appended drawings are described next by way of purely illustrative and nonlimiting example. 
     In the drawings: 
       FIG. 1  is a plan view of a connecting butt strap according to the invention; 
       FIGS. 2 to 5  are views in the direction of the arrows II to V, respectively, in  FIG. 1 ; 
       FIG. 6  is a view in the direction of the arrow VI in  FIG. 5 ; 
       FIG. 7  is a perspective view of the connecting butt strap shown in  FIGS. 1 to 6 ; 
       FIG. 8  is a view similar to  FIG. 7 , showing the connecting butt strap from a different angle; 
       FIG. 9  shows the offering up of connecting butt straps before fitting to a first cable tray; 
       FIG. 10  shows the fitting of the connecting butt straps to the first cable tray; 
       FIGS. 11 and 12  show the locking of the connecting butt straps in position on the first cable tray; 
       FIG. 13  shows the position of the connecting butt straps premounted on the first cable tray, which can be shipped in this condition; 
       FIGS. 14 and 15  show two steps of offering up a second cable tray to be connected to the first; and 
       FIGS. 16 and 17  show the fitting and locking of the connecting butt straps to the second cable tray,  FIG. 17  being a view in section taken along the line XVII-XVII in  FIG. 16 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 to 8 , there is shown a connecting butt strap  30  for butt jointing two wire cable trays  10 ,  20  (see  FIG. 14 ). 
   The wire cable trays  10 ,  20  comprise a mesh formed of wires of two different types, namely, in the case of the cable tray  10 , longitudinal wires  11  that run longitudinally and in a rectilinear or substantially rectilinear manner over the whole of its length and, from place to place along the longitudinal wires  11 , at a regular pitch and appropriately attached thereto, transverse U-shaped wires  12 , the combination globally forming, in the manner of a trough, three panels  13 ,  14 , namely a bottom panel  13  and two lateral panels  14 . All this is known to the person skilled in the art. 
   In practice, the wires  11 ,  12  are metal wires, to be more specific steel wires, and they are welded together where they cross over. 
   Because of this method of construction, the wires  11 ,  12  cross at different levels; in this example, the longitudinal wires  11  are on the outside of the transverse wires  12 . 
   In the embodiment shown, all the wires  11 ,  12  are round wires, i.e. have a circular cross section. 
   As shown here, the diameter of the cross section is the same for all the wires, but this is not necessarily always the case. 
   In the embodiment shown, the bottom panel  13  has no longitudinal wire  11  and each lateral panel comprises only two longitudinal wires  11 , namely an intermediate longitudinal wire  11 , at substantially half its height, and an edge longitudinal wire  11 . 
   However, the number of longitudinal wires  11  can of course be different; similarly, the bottom panel  13  can incorporate any number of longitudinal wires  11 . 
   The cable tray  20  is identical to the cable tray  10  and its component parts are identified by reference numbers derived from those of the cable tray  10  by adding  10  thereto. 
   The traverse wire  12 ,  22  being U-shaped, the have Wings  15 ,  25  and cores  16 ,  26 , respectively. 
   As the person skilled in the art knows, the longitudinal wires  11 ,  21  are usually referred to as warp wires and the transverse wires  12 ,  22  as weft wires. 
   To butt joint the cable trays  10 ,  20 , they are prepared so that, at the end at which they are to be butt jointed, the warp wires are cut off in line with the end weft wire, which is then at the end of the corresponding cable tray, as can be seen in the figures. 
   The connecting butt strap  30  includes clipping means adapted to clip said connecting butt strap  30  to the weft wires  12  and  22  at the ends of the cable trays  10  and  20 . 
   The connecting butt strap  30  comprises a U-shape body  31  having two flanges  32 ,  34  and a core or intermediate portion  33  between the two flanges  32 ,  34 . 
   The core  33  is extended by a clipping rim or tab  35  globally perpendicular to the core  33  and to the flanges  32 ,  34  of the U-shape body  31 . 
   Here, the core  33  of the U-shaped body  31  has a clipping rim  35  at each end. 
   The clipping means or clipping arrangement are defined between, on the one hand, the lateral edges  36 ,  37  of the clipping rim  35  and, on the other hand, each of the flanges  32 ,  34  of the U-shaped body  31 , so that lateral edge  36  and flange  32  form a first portion of the clipping arrangement, and lateral edge  37  and flange  34  form a second portion of the clipping arrangement. 
   To be more precise, the lateral edges  36 ,  37  are at a distance from the flanges  32 ,  34  that is globally equal to or very slightly greater than the diameter of the weft wires  12 ,  22 , and the clipping function is assured by a protuberance  45  preceded by an entry bevel which have said lateral edges  36 ,  37  in the vicinity of their end, said protuberance  45  defining with the flanges  32 ,  34  a passage whose width is less than the diameter of the weft wires  12 ,  22 . 
   Thus it is possible to clip a connecting butt strap  30  to each wing  15  of the weft wire  12  at the end of the cable tray  10 , from the interior toward the exterior, as shown in  FIGS. 9 ,  10  and  14  to  16 . 
   Clipping the connecting butt straps  30  to each of the wings  15  of the weft wire  12  enables said connecting butt straps  30  to rotate about said wings  15 . 
   To reinforce this clipping, the flange  32  that retains the clip  30  incorporates a slot  38  defining a tongue  39  adapted to be bent over the wing  15  of the weft wire  12  until it is practically perpendicular to the flange  32 , as can be seen in  FIGS. 11 and 12 ; the slot  38  is advantageously slanted so that the diameter of the weft wire  12  is immaterial; in  FIG. 11 , the tongues  39  of both connecting butt straps  30  are bent; in  FIG. 12 , the tongues  39  of the connecting butt strap  30  are shown bent. 
   The flange  34  of the U-shaped body  31  is extended by a locking element embodied by a locking or latching rim  40 ; in the embodiment shown in the figures, the locking rim  40  is generally parallel to the core  33  of the U-shape of the U-shaped body  31 . 
   The locking rim  40  carries a locking lug  41  in line with the edge of the groove  43  in said locking rim  40 . 
   The locking rim  40  is generally parallel to the core  33  of the U-shape of the U-shaped body  31  and the groove  43  is parallel to the clipping rim  35  and at substantially half its height relative to the flanges  32 ,  34  of the U-shaped body  31 , to which it is substantially perpendicular. 
   In the embodiment shown, the locking rim  40  extends the flange  34  of the U-shaped body  31  over the full height thereof. 
   Relative to the locking rim  40 , the bottom of the groove  43  extends from the same side as the core  33  of the U-shaped body  31  and the locking lug  41  is on the opposite side; thanks to this arrangement, the locking lug  41  can be bent at  42  over a wire lying in said groove  43 , in this example a warp wire, to lock the connecting butt strap  30  relative to said wire in the connection position, as explained below. 
   The groove  43  is extended by a notch  44  in the core  33  and the flanges  32  and  34  of the U-shaped body  31  for the warp wire to pass through. 
   The two connecting butt straps  30  being mounted to rotate about the wings  15  of the weft wire  12  at the end of the cable tray  10 , as can be seen in  FIGS. 11  and  12 , it suffices to pivot them toward the interior of the cable tray  10 , in particular so that they lie along the lateral panels  14 , in a storage position, as can be seen in  FIG. 13 , and the cable tray  10  can be shipped in this configuration, with the connecting butt straps premounted. 
   To connect the cable tray  10  to an identical cable tray  20 , the connecting butt straps  30  are deployed outward, by rotating them about the wings  15  of the end weft wire  12 , the cable tray  20  is moved toward the cable tray  10 , and the connecting butt strap  30  is inserted into the cable tray  20 , as can be seen in  FIGS. 14 and 15 . 
   The connecting butt straps  30  are turned further outward until the flange  34  and the clipping rim  35  overlap until the wing  25  of the weft wire  22  of the cable tray  20  is clipped and until the groove  43  caps the warp wire  24  of the cable tray  20 , as can be seen in  FIGS. 16 and 17 ; in this position, the locking lug  41  extends toward the exterior of the cable tray  20 ; it suffices to bend this lug to lock the connecting butt strap to the warp wire  24 ;  FIG. 16  shows the locking lug  41  of the upper connecting butt strap  30  before bending and that of the lower connecting butt strap  30  after bending. 
     FIGS. 11-17  show an alternate clipping tab  35 ′.