Patent Publication Number: US-2022224090-A1

Title: Intersection system for overhead cable trays

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application claims benefit to U.S. Provisional Patent Application No. 63/136,289, filed on Jan. 12, 2021, the entirety of which is hereby incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The present application is for a cable tray system used to support cables and couple cable trays at an intersection. 
     BACKGROUND 
     Cable tray systems generally provide support for cables such as electrical wiring, conduit and data transmission lines. The cable tray may be a wire-basket cable tray having interconnected metal wires in a mesh. 
     Cable trays are connected to other cable trays at intersections to route the cables and form a cable tray system. The intersections may be a three-way or T-intersection, or a four-way or cross-intersection. 
     SUMMARY 
     According to one embodiment, a cable-tray intersection system is provided. The intersection system connects a first wire basket that intersects a second wire basket along a cable route. Each of the first and second baskets is formed of a plurality of wires extending horizontally to form a floor, and a plurality of wires extending vertically forming the side walls of the basket. The intersection system has a top plate having a first edge for mounting on the floor of the first wire basket, and a second edge for mounting on the floor of the second wire basket. The top plate has a pair of corner edges formed between the first edge and the second edge. Each corner edge is formed on opposite lateral sides of the top plate. A pair of corner braces are mounted between and to the first wire basket and the second wire basket and spaced apart from the top plate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a cable-tray system with two wire baskets being arranged to connect at an intersection. 
         FIG. 2  illustrates the cable-tray system of  FIG. 1  with an exploded view of the top plate and clamps according to one embodiment. 
         FIG. 3  illustrates a cross section through a clamp location between the top plate and the floor of the wire basket. 
         FIG. 4  illustrates the cable-tray system of  FIG. 2  with a pair of corner braces. 
         FIG. 5  illustrates one of the corner braces in more detail. 
         FIG. 6  illustrates the cable-tray system in  FIG. 4  with one of the corner braces suspended by a support rod. 
         FIG. 7  illustrates the cable-tray system in  FIG. 4  with one corner protector installed. 
         FIG. 8  illustrates one of the corner protectors in more detail. 
         FIG. 9  illustrates a top view of a cable-tray system according to one embodiment having a three-way intersection. 
         FIG. 10  illustrates a perspective view of the cable tray system of  FIG. 9 . 
         FIG. 11  illustrates a perspective view of a cable tray system according to one embodiment having a four-way intersection. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Overhead wire baskets are made of steel wire mesh and are designed to route cables. As two perpendicular wire baskets intersect, it is necessary to secure the junction and cover the ends of wires. 
       FIG. 1  illustrates a cable-tray assembly  100  with two intersecting wire baskets that are preformed and arranged to connect at an intersection. A first wire basket  110  intersects a second wire basket  120 . Each of the first and second baskets  110 ,  120  is formed of a plurality of crosswires extending horizontally to form a basket floor  122  and a plurality of wires extending vertically forming side walls  124  of the baskets  110 ,  120 . 
     As shown in  FIG. 1 , the first wire basket  110  may be a terminating basket having a terminal end  128 , whereas the second wire basket  120  may be a continuous wire basket  120  where the floor  122  extends continuously through the intersection. 
     The intersection is formed by cutting an opening  126  in the side wall  124  from the continuous second wire basket  120  and abutting it to the end  128  of the terminating first wire basket  110  at the cut opening location  126 . The side walls  124  of the terminating wire basket  110  may be cut off, to provide corner relief as described later, while allowing the floor wires  122  of the terminating wire basket  110  to come as close as possible to the continuous wire basket  120 . Minimizing the gap between the floor wires of the terminating wire basket  110  and the continuous wire basket  120  increases the strength of the intersection. 
     As shown in  FIG. 2 , the cable tray system  100  has a preformed intersection system  200  to securely join the first wire basket  110  to the second wire basket  120 . The intersection system  200  has of a top plate  210  which covers cut ends  128  of the wire basket floor wires  122  and provides rigidity to the assembly. Other prior cable-tray systems do not allow for a continuous wire basket and instead may have multiple terminating wire baskets adjoining at an intersection. In these systems, the top plate is required to span the entire intersection. This requires the top plate to be larger, and heavier and provide all the rigidity for the intersection. In these prior systems the top plate is limited to exact sizes of the wire baskets and does not allow for flexible assembly variations. The top plate  210  of the present application allows for different configurations of intersections with only one top plate. The top plate  210  may be provided in multiple sizes, specific for each terminating wire basket  110  width, however the size of the top plate  210  is independent of the second wire basket  120  and can be used with any width continuous basket  120 . While also being lighter, the top plate  210  provides increased rigidity over prior designs because the continuous wire basket  120  itself spans the intersection. 
     The top plate  210  has a first edge  212  for mounting on the floor  122  of first wire basket  110 , and a second edge  214  for mounting on the floor  122  of the second wire basket  120 . The top plate  210  has a pair of corner edges  218  formed between the first edge  212  and second edge  214 . Each corner edge  218  is formed on opposite lateral sides  216  of the top plate  210 . The edges  212 ,  214 ,  216  of the top plate  210  may be rounded flanges or bent perpendicular to the direction of cable routing, to prevent abrasion or damage to cables from the edges of the top plate  210 . 
     The top plate has a plurality of elongated slots  220  extending through the top plate  210  from the upper surface  226  to the lower surface  228 , as shown in  FIG. 3 . A plurality of carriage bolts  222  fit through slots  220  in the top plate  210 . U-shaped clips  230  clamp the crosswires on the floor  122  to the top plate  210  and are secured to the carriage bolts  222  with locknuts  224 . Since the location of the top plate  210  can vary with respect to the location of crosswires on the floor  122 , the slots  220  must be long enough or be arranged in groups of shorter slots, to assure that each U-clip  230  can reach a crosswire.  FIG. 3  illustrates a cross-section through a clamp location between the top plate  210  and the floor  124  of the wire basket in more detail. 
       FIG. 4  illustrates a partially exploded view of the cable-tray intersection system  200  showing the top plate  210  assembled to the floor  122  of the first and second wire baskets  110 ,  120 . The top plate  210  may include beads  236  to increase its rigidity and the rigidity of the intersection.  FIG. 4  also illustrates the intersection system  200  having a pair of corner braces  300 . The corner braces  300  are mounted between to the first wire basket  110  and the second wire basket  120  and spaced apart from the top plate  210 . The corner braces  300  are attached to the side walls  124  of each of the wire baskets  110 ,  120  to stiffen the cable-tray assembly  100 . 
     Each corner brace  300  is rigid and formed of metal.  FIG. 5  illustrates the corner brace  300  in more detail. Each corner brace  300  has radial central portion  310  and a pair of rigid legs  312 . As shown in  FIG. 6 , one leg  312  is secured to the first wire basket  110  and the other leg  312  is secured to the second wire basket  120 . 
     The corner braces  300  are secured to the wire baskets  110 ,  120  using clips  320 . As shown in  FIG. 4 , the clips  320  may have studs  322  configured to extend through and engage slots  314  (see  FIG. 5 ) on the corner brace  300 . The studs  322  may be threaded studs to engage a corresponding nut  324  to clamp the vertical crosswires along the side walls  124  of the wire baskets  110 ,  120  to the corner braces  300 . The studs  322  may be any threaded fastener or other suitable fastener to secure the clips  320  to the slots  314 . 
     To reduce the deflection of the intersection and provide further rigidity, the corner braces  300  may have an angled wall  328  connecting the legs  312 . The corner braces  300  have a mounting feature  330  for securing a support rod  400  for hanging the cable-tray system  100  in a facility, as shown in  FIG. 6 . 
     As shown in  FIG. 5 , the mounting feature  330  has a hole  332  extending generally vertically to secure the wire baskets  110 ,  120  to support rod  400 . The mounting hole  332  is formed in a tab  334 . The support rods  400  which hang from the ceiling, pass through the holes  332 . Locknuts  402  secure the intersection system  200  to the support rods  400  (see  FIG. 6 ). 
     As shown in  FIG. 5 , the tab  334  may extend from the angled wall  328  or the radial center portion  310 . The mounting feature  330  is positioned outside side walls  124  to secure the rods outside of the wire baskets  110 ,  120 . Prior cable-tray systems required the rods to be secured to the top plate which positioned the hanging rods in the cabling pathways. The intersection system  200  having the mounting features  330  outside the wire baskets  110 ,  120  provides numerous advantages including better cabling pathways without obstacles that impede routing of the cables at the intersection. 
       FIG. 7  shows the cable-tray intersection system with one of corner protectors  500  installed. The corner protectors  500  are designed to cover cut wire ends of the side walls  124  and/or the floor  122  and to provide bend radius control to the cables around corners. Each corner protector  500  is positioned between one corner brace  300  and a corner edge  218  of the top plate  210 . 
     The corner protectors  500  are formed of flexible plastic. The corner protectors  500  may be made of a flame rated plastic. As shown in  FIG. 8  the corner protectors  500  are supplied flat. Each corner protector  500  has a pair of flexible arms  502  extending from opposite sides of a flexible body  504 . The corner protectors  500  are installed by first bending the arms  502  under the vertical crosswires of the side walls  124 . One arm  502  is secured to the first wire basket  110  and the other flexible arm  502  is secured to the second wire basket  120 . Then the corner protectors  500  are secured with fasteners  510  (see  FIG. 7 ) to the intersection system  200 . The fasteners  510  may plastic ribbed push-in rivets or Christmas-tree fastener. As shown in  FIG. 7 , two fasteners  510  are installed through the lower slots  512  and two fasteners are installed through the upper slots  514 . 
     The top plate  210  has a plurality of tabs  520  extending from the corner edges  218 . The lower slots  512  are aligned with fastener holes on the tabs  520  and the fastener  510  extends through one of the slots  512  and engages the fastener hole on one of the tabs  520  to secure the corner protector  500  to the top plate  210 . 
     The corner protectors  500  may abut the top plate  210  with no gap or a minimum gap between the bottom edge  516  of the corner protector  500  and the top surface of the top plate  210 . The fasteners  510  are installed through the upper slots  514  and engage holes  340  in the corner braces  300 . The upper slots  514  are sized to account for height tolerance of the side walls  124  of the wire baskets  110 ,  120 . The lower slots  512  are sized to account for horizontal misalignment between the top plate  210  and the corner braces  300 . As such, the corner protectors  500  can be easily secured to the intersection assembly  200  even with tolerance or misalignment issues in the wire baskets. The arms  502  of the corner protectors  500  may be secured to the vertical crosswires of the wire baskets  110 ,  120  with cable ties threaded through the holes  518  (see  FIG. 8 ). 
     The intersection system  200  provides flexibility in providing different intersection configurations without needing different configurations of top plates. For example,  FIGS. 9-10  show a cable-tray system  600  using the intersection system  200  that forms a three-way intersection configuration  610 . In another example,  FIG. 11  shows a cable tray system  700  that forms a four-way intersection configuration  710 . 
     As illustrated in  FIG. 9  and  FIG. 10 , the three-way intersection configuration  610  forms a T-shaped intersection. The three-way intersection configuration  610  uses a continuous wire basket  120  where the first wire basket  110  abuts the opening  126  in the side wall  124  of the continuous wire basket  120 . The three-way intersection configuration  610  uses one top plate  210  and one pair of corner braces  300 .  FIGS. 9-10  also show trapeze brackets  620  offset from the intersection. The trapeze brackets provide mounting features for connecting support rods  400 , as is common in typical installations. The present application provides corner braces  300  with mounting features  330  for connecting the support rods  400  to be positioned outboard of the cable pathway at the intersection. Therefore, the support rods  400  adjacent the intersection  610  also align with the support rods  400  at the trapeze brackets  620  along the length of the wire baskets  110 ,  120 , as shown in  FIG. 9 . 
     As illustrated in  FIG. 11 , the four-way intersection configuration  710  forms a cross-shaped intersection. The four-way intersection configuration  710  uses a continuous wire basket  120  and two terminating wire baskets  110  that each abut openings  126  in opposite side walls  124  of the continuous wire basket  120 . The four-way intersection configuration  710  uses two top plates  210  and two pairs of corner braces  300 . The four-way intersection configuration  710  may also use trapeze brackets to connect support rods  400 . Note that, for clarity, the trapeze brackets and the support rods are not shown in  FIG. 11 . 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.