Abstract:
A collection of components for a cable tray system provide the components and basic hardware for assembling and installing a cable tray that can change direction in three dimensions to avoid obstacles or other cables&#39; trays while negotiating a designated space. Components of the cable tray system may be modular, that is, pre-configured for ease of assembly, such as vertical kits and horizontal bend kits, while others are supplied in lengths for cutting them to fit jobsite requirements, such as rails and rungs. Both components provide an inherent framework that facilitates conceptualization and construction of a cable tray system at the jobsite with flexibility and simplicity to allow the present cable tray system to be employed more efficiently and accurately.

Description:
PRIORITY CLAIM 
     None 
     BACKGROUND OF THE INVENTION 
     Cable trays (sometimes called cable races) are found in commercial and industrial facilities, power generation facilities, manufacturing plants, and the like. These trays and their related hardware are used to support, guide, contain, and help manage cables, tubes, pipes, conduits, and wires that must be run from one part of the facility or plant to another. Examples of cable trays may be found in U.S. Pat. No. 4,232,845, U.S. Pat. No. 3,137,468, U.S. Pat. No. 4,432,519 and U.S. Pat. No. 6,498,296, which are incorporated herein by reference. 
     The primary requirement for a completed cable tray system is structural rigidity. In many applications, the cable tray system is also designed to minimize or eliminate electrical arcing between connected parts of the system by maintaining electrically conductive continuity in the event that the system becomes electrically energized. 
     Cable trays typically are formed from linear runs of trays connected together to span the length of a facility. Sections of trays are fastened together to achieve the requisite length and shape. Occasionally, an entire cable tray may be installed in a straight line without interruption. More often than not, however, previously installed or permanent structures, such as support columns, walls, and other cable trays, are obstacles to the installation of a linear cable tray and therefore require a cable tray to negotiate its path around these other structures and depart from its otherwise straight-line trajectory. In some circumstances, a cable tray running from one location to another within a single facility may need to change direction and elevation perhaps more than once along its path. 
     Ladder-type cable trays are known. These are constructed from spaced-apart rails to which rungs are welded to form a “ladder-like” framework or section that will support cables with less material. The latter tray sections are shipped to the jobsite where they are connected together, section by section. 
     Designs may need to be carefully and accurately drawn out in advance to be sure that the cable tray layout for a facility will be installed efficiently and accurately. 
     Even when the cable tray design is complete, flexibility may still be needed during the installation process in the field to achieve a satisfactory outcome. Accordingly, it would be advantageous to have flexibility in cable tray design to accommodate real world applications. 
     SUMMARY OF THE INVENTION 
     The present cable tray system comprises a collection of components for designing and installing cable trays that accommodates changes in direction in up to three dimensions to avoid obstacles as it negotiates its way across a space. Importantly, the present cable tray system has sufficient capability and flexibility that it can be built on site, cutting certain components to fit as needed. Components of the present cable tray system include those that are modular, that is, they are pre-cut and formed for practically any directional change and support need by the cables to be run. It also includes those components that are most conveniently cut to fit at the job site. Importantly, many of the modular components “nest” with each other for more efficient packaging or banding, storage, inventorying, transportation, and staging. In addition and where possible, the basic components of the system are supplied in lengths that allow them to be spliced together and cut to fit precisely to thereby reduce the number of different components that have to be used to complete a cable tray. 
     The term cable tray is used herein to mean a long support for one or more cables between two points in space, which tray may change direction in three-dimensional space. The term tray is used generally and historically as a cable support but it does not mean the cable tray is a solid, continuous surface, only that it provides support underneath the cables. 
     This combination of pre-configured and job-site, cut-to-fit components form the basis of a cable tray system. Its kit-like nature and the specific features of its components enables the design of a cable tray system with the flexibility needed for real-world applications. Thus the present cable tray system may be used to design and install a wide assortment of three dimensional cable trays efficiently and accurately. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures, 
         FIG. 1  illustrates in perspective a portion of a cable tray, according to embodiments of the invention; 
         FIGS. 2A, 2B, 2C and 2D  illustrate an end view of a cable tray, including  FIG. 2A  showing a rung attached inside the rail with the rung partially cut away to show one type of clamp holding two of the pipes to the rung,  FIG. 2B  showing a similar rung attached below the rails,  FIG. 3C  showing an alternative flat rung, and  FIG. 2D  showing a cable tray with channel rung on its ledges and with a large number of cables carried thereon, according to embodiments of the present invention; 
         FIGS. 3A, 3B, and 3C  illustrate spacers in connecting rungs to rails, with  FIG. 3A  showing an exploded view of a rung between two rails with a spacer for elevating the rung from the ledges of the opposing rails, according to an embodiment of the invention,  3 B illustrating an elongated closed spacer, and  3 C illustrating individual tubular spacers, according to alternative embodiments of the present invention 
         FIGS. 4A-4C  illustrate in perspective different mounting devices for cable trays, namely, a hanger bracket is shown in  FIG. 4A , a turn-out hold down mount is shown in  FIG. 4B , and a turn-in hold down mount is shown in  FIG. 4C , according to embodiments of the invention; 
         FIGS. 5A, 5B and 5C  illustrate in perspective three alternative vertical fitting kits, a first vertical fitting kit for a 90-degree vertical elbow joint shown in  FIG. 5A , a second vertical fitting kit for a radius bend shown in  FIG. 5B , and a third vertical fitting kit in  FIG. 5C  show without cables so its rungs can be easily seen, according to embodiments of the invention; 
         FIGS. 6A and 6B  illustrate top view and a top perspective view of a horizontal inside and an outside bend elbow joint with a diagonal rung for supporting pipes traversing a 90-degree horizontal bend, according to an embodiment of the invention; 
         FIG. 7  illustrates a top view of a portion of a cable tray having a main tray and several trays exiting from the main tray laterally, according to an embodiment of the invention; 
         FIG. 8  illustrates a cover with hold down clamps on a section of cable tray according to an embodiment of the invention; 
         FIGS. 9A-9H  illustrate examples of different rung material with different hole patterns for use with the present cable tray system, according to an embodiment of the invention; 
         FIGS. 10A, 10B, and 10C  show cable brackets, namely,  FIG. 10A  which shows a perspective view of a section of cable tray in a 90 degree vertical bend with three types of conduit or piping held by two clamps to a rung,  FIG. 10B  which shows in more detail a pipe or conduit secured by the first type of bracket; and  FIG. 10C  which shows two pipes or conduits secured by the second type of bracket. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is a cable tray system. The present cable tray system is useful for the design and installation of an elevated cable tray that crosses a space while avoiding other structures in that space as it runs from one part of that space to another. For example, when cables run from one or more buildings to another, more than one cable tray may be established to provide elevated, rigid paths for the cables and which cable trays avoid obstacles and each other as they cross that space, thereby protecting the cables while also keeping them organized during construction, verification, inspection, maintenance and repair. 
     By the term system, it is meant that the components cooperate with each other so that a designer and installer can design and install a cable tray meeting any of innumerable different requirements simply by selecting from among those components the number and size of components necessary and then cutting and connecting those components according to their nature, as described herein, to obtain the desired combination of straight runs and vertical, diagonal, and horizontal turns needed to cross that space without interference with existing obstacles and other cable trays. In a sense the present system can be used to specify a kit from which a specific cable tray design for a specific application can be assembled. That kit can be stored, shipped to the construction site, staged, and assembled. The system can be used to satisfy the specifications of an endless number of such kits for specific cable tray design requirements. Moreover, the various components of which the system is comprised are collectively designed to meet the needs of most cable tray requirements, to interconnect easily and rigidly, to store and ship compactly, and to allow flexibility in meeting real world requirements of the jobsite. 
     The term “cable” is used for convenience herein to represent any electrical, coaxial, and fiber optic wiring or cabling, as well as fluid hoses, conduit, piping and other tubular structures intended for delivery of fluids, gases, electrical current, and electrical and optical signals, including tubular structures reserved for future use. 
     The purpose of the cable tray is to protect cables from hazards and to organize the cables so that individual cables can be easily distinguished from each other, their paths more easily plotted, followed, and verified, and their servicing and repairing simplified. 
       FIG. 1  and  FIGS. 2A, 2B, 2C, and 2D  illustrate a section of cable tray, generally indicated by reference number  10  and three different rung and cable arrangements. 
     Cable tray  10  includes rails  14  and rungs  18  that may be fastened together in a configuration similar to a ladder. The ends of rungs  18  are attached at intervals to two opposing, spaced-apart rails  14 . Rungs  18  are fastened along the axial length of rails  14  where and as needed to provide support for the cables running between rails  14 , particularly near joints and near changes in direction in cable tray  10 , and to provide a sufficiently rigid cable tray  10  for running across a space at elevation and unsupported. For a wider cable tray  10  to hold more and larger cables, for example, rungs  18  may be longer and wider and spaced closer together. Rails  14  may be L-shaped (as shown) or C-shaped for greater stiffness. Rungs  18  may be flat or channel rungs depending on the stiffness and strength needed for cable tray  10 . 
     Rails  14  have plural holes  22  formed therein; rungs  18  have plural holes  50  formed therein to facilitate connection. 
       FIG. 1  also shows a pair of splice connectors  26 , according to embodiments of the invention. Splice connectors  26  may be used wherever two successive rails  14  are to be joined end-to-end, and may not necessarily be used directly opposite another splice connector  26  on cable tray  10  as shown in  FIG. 1 , but rather wherever needed on either side of cable tray  10  as it negotiates the space required. Splice connectors  26  have plural holes  30  formed therein to facilitate connection with rails  14   
     Splice connectors  26  may have the same shape as rails (C-shape or L-shape) but be slightly larger in size than rails  14  so that rails  14  nest within splice connectors  26  as shown in  FIG. 1 . Nesting means that the splice connector  26  may be placed in engagement with a rail  14  so that there is full contact of the faces of rail  14  against the faces of the splice connector  26  despite bends formed in their engaging surfaces to form those faces. See also  FIGS. 2A, 2B, and 2C , to see nesting of rails  14  inside splice connectors  26 . 
     The ladder-type aspect of the present cable tray  10  is important from two standpoints. First, forming cable tray  10  from rails  14  and rungs at the jobsite provides complete flexibility in meeting the real world requirements. Rungs  18  are cut from rung material to be as long as the cable tray  10  needs to be wide; rails  14  may be cut from rail material or spliced as shown in  FIG. 1 . Second, the shipping, storing, and staging of components for cable tray  10  are much smaller when the individual components are not bulky. Accordingly, the additional assembly time is offset by reduced waste and lower shipping, storage and staging costs. 
     Rungs  18  are relatively short compared to rails  14  to which they are attached. Rail material may be provided in standard lengths, such as 6 m (20 feet). Rung material may also be provided in 3.6 m lengths (12 feet). Rail material and rung material are easily shipped in banded bundles. 
     Accordingly, rung material is divisible into rungs  18 , which are lengths of formed metal or other rigid, structural material. Rail material may be used without dividing it if cable tray  10  runs far enough without change in direction, or it may be cut as needed. The rail material may not be the same type of material as the rung material. 
     Another aspect of the present cable tray  10  is that individual cables can be turned 90 degrees horizontally or vertically between rungs  18  from an initial direction. A tray-like cable tray simply does not permit that flexibility and a ladder-type cable tray has rungs welded in place, which rungs may be in a location where the installer needs to run a cable. In the present cable tray  10 , rungs  18  may be placed where needed or convenient thereby providing additional flexibility in having cables on cable tray  10  diverge from the primary path to pass between the rungs  18 . 
     The coordination of the holes in rails  14 , rungs  18  and splice connectors  26  is an important feature of the present invention. In connecting rungs  18  to rails  14  and splice connectors  26  to rails, holes  22 ,  50 ,  30  of rails  14 , rungs  18 , and splice connectors  26 , respectively, may be brought into registration so that two holes in each component align with two holes in the other, forming a registration pair. Bolts  34  are used to join rungs  18  to rails  14  and splice connectors  26  to rails  14  by being inserted into the registration pairs and tightened with nuts. Rungs  14  are joined to rails  14  by aligning the holes in ledges  38  and tightened with pairs This feature also includes fastening splice connectors  26  by aligning their holes  30  with the holes  22 . Holes  30  may be elongated to facilitate alignment and connection. See also  FIG. 2A . 
     Rungs  18  may be fastened below (as shown in  FIG. 2B ) or inside of rails  14  (as shown in  FIGS. 2A, 2C, and 2D ). Whether rails  14  are L-shaped or C-shaped, opposing rails  14  have ledges  38  of the bottoms of the L or C that extend toward each other when rails  14  are aligned for assembling a cable tray  10  in order to provide two parallel, co-planar surfaces for rungs  18  to be attached by fasteners such as bolts. Other components may be also supported like rungs  18  by rails  14 , such as struts, which are known in the prior art.  FIG. 1  and  FIG. 2A  show rungs  18  fastened on tops of ledges  38  of opposing rails  14  and to the underside of opposing rails  14 .  FIG. 2B  shows a rung  18  fastened to the bottoms of ledges  38  of opposing rails  14 .  FIG. 2C  shows a flat rung  18  supported by two opposing rails  14 . 
       FIG. 2D  shows a rung  18  fastened to the top of ledges  38  of two spaced-part rails  14  using bolts  48  to stack cables  46  held in place by cable clamps  42 .  FIG. 2D  illustrates the capacity of the present cable tray  10  to hold a large number of cables  46  in an organized fashion so that they can be traced easily in installation and maintenance. 
       FIGS. 3A, 3B, and 3C  illustrate spacers used in positively connecting rungs  18  to rails  14 .  FIG. 3A  illustrates rung  18  supported by the ledges  38  of two opposing rails  14  on spacers  40 . Spacer  40  is a piece of flat metal stock rolled on its opposing ends into a “C” shape, as shown in  FIG. 3A , or a spacer may be in the form of elongated loop  36 , as shown in  FIG. 3B , or two separate cylinders  44 , as shown in  FIG. 3C , any of which can receive the shafts of two bolts. Spacer  40  assures good physical and positive metal-to-metal contact between rails  14  and rungs  18 , provides a good structural connection between rungs  18  and rails  14  and provides for clearance to access the bottom of rung  18  and ledge  38  of rail  14 . 
       FIGS. 2B-2D  and  FIGS. 10A-10C  show clamps  42  for securing a cable  46  to a rung  18 . A clamp  42  is fastened to rung  18  and, with cable  46  thus held in place, clamp  42  is tightened to rung  18  to secure cable  46 . Clamp  42  is not a component of the present system but may be any one of numerous clamps for holding cable  46  to a cable race surface. Indeed, the pattern of holes  50  in rung  18  of the present invention (See  FIGS. 9A-9G ) is intended to accommodate various standard cable clamps and supports. The coordination of the pattern of holes  50 , generally round holes, as shown in this example, which provides for the great flexibility provided in combining the components of the present invention to accommodate a large number of designs possible for cable tray  10 . By coordination of the holes  50 , it is meant that at least two holes  50  on every rung  18  are spaced apart by the same distance as two or more holes  22  on every rail  14  and on every other component that a rail  14  would be connected to, such as a splice connector  26 . Similarly, two or more holes would be spaced apart by the same distance on any other two components that maybe joined, so that such holes on different components may be form alignment pairs so that fasteners may be inserted through the alignment pairs of the components placed in engagement with each other. Furthermore, at least two holes on every component that may be joined to any other component are spaced apart from other structures carried on that same component that might otherwise interfere with the joining of two different components. 
     Rungs  18  provide sufficient support when properly spaced-apart for supporting cables  46 . Rails  14  support rungs  18  and cooperate with each other to establish a sufficiently rigid and relatively light-weight structure to support a run of plural cables  42 . The height of rails  14  may be the same on both sides of cable tray  10  or greater on one side of a cable tray  10  depending on the number of cables being supported and the number of layers of cables on each cable tray  10 . 
     Rungs  18 , as with rails  14 , have an array of holes  50  formed therein for use in attaching cable clamps  42 , as best seen in  FIG. 9A-9G . Holes  50  in rungs  18  may be made in various patterns and include round holes and square holes, perhaps in an alternating array of square holes and round holes. Importantly, in every set of holes perpendicular to the long dimension of the rungs  18 , there are at least two round holes spaced apart by 5 cm (2 inches) center-to-center. Accordingly, when a rung  18  is cut, both of its ends will have those two, 5 cm sp to aced-apart, round holes. While the 5 cm spacing is arbitrary, it is compatible with the pattern of holes  22  in the ledges  38  of rails  14  and with cable and hose clamps commonly used with cable trays, so it is preferred. 
     Cable tray  10  is supported at elevation by other structures, such as columns, the ceiling, the floor, walls or installed supports in the space where cable tray  10  is to be constructed.  FIGS. 4A, 4B, and 4C  show different brackets used for providing cable tray  10  support.  FIG. 4A , for example, is a hanger bracket  54  which receives a rod  58  through a hole  60  in bracket  54 . Rod  58  is attached overhead and threaded on its distal end to receive a nut  62  that will enable bracket  54  to hold rail  14  at the appropriate elevation from the overhead support. 
       FIGS. 4B and 4C  show a support bracket  66  turned outside of rail  14  in  FIG. 4B  and turned inside of rail  14  of cable tray  10  in  FIG. 4C . Support bracket  66  may be bolted to rails  14  through holes  22  in the same manner that splice connectors  26  are attached to rails  14 . Support brackets  66  have holes  70 , preferably oblong holes  70 , for adjustability and ease in leveling cable tray  10  once brackets  66  are attached to support structures. 
     For 90-degree vertical bends in cables  46 , two alternative embodiments of components, referred to as fitting kits, are shown. Each of these two vertical fitting kits has symmetric left and right sides that have a generally L-shape. The left and right sides of each fitting kit may be fastened by bolts to a first set of opposing rails  14  oriented vertically and to a second set of opposing rails  14  oriented horizontally so that the ends of two successive rails  14  are joined at right angles. 
     In the embodiment of a first vertical fitting kit  72  shown in  FIG. 5A , left and right sides  74 ,  76 , although generally L-shaped, have gussets  78 ,  80 , respectively, for confining the cables  46  connected by elbow joints  82  through the 90 degree bend and added strength. Left and right sides  74 ,  76  are flat so as to occupy less room in storing and shipping than pre-manufactures elbow. The horizontally-oriented and vertically-oriented rails  14  are relatively close to the center of the bend to provide a smaller gap for elbow joints  82 . Rungs  18  may be installed closer to the bend formed by left and right sides  74 ,  76 , of first fitting kit  72  if added rigidity and strength at these bends is needed. 
       FIG. 5B  shows a similar, second, fitting kit  84  that accommodates a 90 degree radius bend in cables  46  between a left side  86  and a right side  88 . Accordingly, the vertical and horizontal rails  14  are attached to left and right sides  86 ,  88 , of second fitting kit  84  farther from the center of the bend than in first fitting kit  72 . 
     In  FIG. 5C  and  FIG. 10A , a third fitting kit  90  is shown, also, as with second fitting kit  84  without a gusset. Third fitting kit  90  has a left side  92  and a right side  94  and shows horizontal and vertical rails  14  affixed more deeply into left side  92  and right side  94 . In this embodiment as well as that of fitting kit  94 , the top flanges  96  of rails  14  help to hold cables  46  in place. 
       FIG. 10A  shows different types of cables  46 , namely, pipes with elbow fittings  82  secured to rungs  18  by clamps  42 . Both  FIGS. 5C and 10A  show rungs  18  mounted on top of ledges  38  of vertical and horizontal rails  14  of third fitting kit  90 .  FIGS. 10B and 10C  show details of  FIG. 10A  of clamps  42   
     In the case of each of first, second and third vertical fitting kits  72 ,  84 ,  90 , left and right sides are symmetric and flat and can be easily stacked so as to use minimal volume for packing, storing shipping and staging. 
     An alternative to a vertical fitting kit is a horizontal elbow joint for 90-degree horizontal bends, as shown in  FIGS. 6A and 6B . Here, horizontal elbow joint has an inside elbow bend  102  and an outside elbow bend  104 , which are L-shaped or it may have only one of these. Inside and outside elbow bends  102 ,  104 , are bolted rails  14  at opposing ends of each elbow  102 ,  104 . 
     Inside and outside elbows  102 ,  104 , have flanges  110 ,  112 , extending respectively toward the center of the bend and which flanges  110 ,  112 , are joined together by a diagonal rung  116  bolted to each tab  110 ,  112 . Additional rungs  18  may be used on either the entrance to or exit from a horizontal elbow kit  100  for support near the 90 degree horizontal transition. The angle of the bend may be less than 90 degrees when required. 
     Referring now to  FIG. 7 , there is illustrated in a top view an example of a cable tray set  120  with several trays joining to it laterally and one joining vertically. Cable tray set  120  comprises spaced-apart rails  14  and spaced apart rungs  18  connected to rails  14 . A first lateral tray  124  joins a second, main cable tray  128  using two 90 degree horizontal inside elbow bends  102 . Three additional lateral trays  136 ,  140  and  144  join main cable tray  128  from opposing sides of main cable tray  128  using pairs of inside elbow bends  102 . One cable  138  runs vertical off of lateral tray  136 . Cables  160  may be arranged on main cable tray  128  so that they depart, if at all, from the others on main cable tray  128  in order, that is, from the first to depart to lateral tray  136  being the left-most cable, the second to depart to lateral tray  140  being the second-leftmost cable, and so on. Diagonal rungs  116  (see also  FIG. 6B ) provide additional support for the cables that pass through or bend away from the intersections of main cable tray  128  to lateral trays  124 ,  136 ,  140 , and  144 . A vertical fitting kit  158  is used to turn cable  138  in a vertical direction of second lateral tray  136 . 
     It will be clear that numerous vertical fitting kits can also be combined with horizontal elbow fitting kits to have cables join or depart the main set of cables in either horizontal or vertical directions as needed and where needed. The use of rungs  18  in combination with rails  14  permits vertical up and down departures of, say, a portion of the cables through the gaps between rungs  18  as the remainder of the cables continue to the next rung  18 . 
     Referring now to  FIG. 8 , there is illustrated a cable tray  10  with a cover  170  for us when the cables on the cable tray  10  need to be protected from rain or heat from above. Simple clips  174  may be used to hold cover fast to rails  14  using a bolt  178  attached to a hole  22  in rail  14  and be easily loosened for servicing. 
       FIG. 9A-9H  show rung material in both channel and flat cross sections, of different widths, and having different patterns of holes that permit easy attachments of various cable clamps  42  to be made. All may be used with spacers as shown in  FIGS. 3A-3C . 
       FIG. 9A  illustrates wide channel-type rung material  178 . Rung material  178  has rows  180  of round holes  184 . Any division of rung material  178  perpendicular to its major dimension to form a rung  18  will leave row  180  of at least two round holes  184  near the edge defined by the division. 
       FIG. 9B  illustrates narrow channel-type rung material  186 . Rung material has rows  188  of round holes  190  and square holes  192 . Any division of rung material  186  perpendicular to its major dimension to form a rung  18  will leave row  188  of at least two round holes  190  near the edge defined by the division. 
       FIG. 9C  illustrates wide channel-type rung material  194 . Rung material  194  has rows of round holes  198  and square holes  200 . Any division  196  of rung material  194  perpendicular to its major dimension to form a rung will leave a row of at least two round holes  198  near the edge defined by the division. 
     Various cable supports will require 5 cm (2 in.) center to center spacing in the attachments can be used easily without modification of the components of the kit and provide good metal-to-metal contact and secure attachment. 
     Certain of the elements described above come in fixed lengths which may be cut to fit at the job site, including rails  14 , rods  58  for hanger brackets  54 , rungs  18 , diagonal rungs  116 , and covers  170 . Other components, including splice connectors  26 , hanger brackets  54 , channel hold down brackets  66 , vertical fitting kits (with and without gussets)  72 ,  84 ,  90 , horizontal elbow fitting kits  100 , hold down clamps for covers  174 , cable clamps  42 , and all fasteners, are pre-cut and pre-formed. 
     Some components come in several sizes and shapes such as rungs  18 , rails  14 , splice connectors  26 . Rails  14 , may be C-shaped or L-shaped, and their upper flanges, if present, may be shorter than ledges  38 . Horizontal elbow kits  100  nominally are available for 90 degree bends but may be available for bends of other angles and may be provided in various sizes. 
     Those skilled in cable tray design and construction will understand that various modifications and substitutions may be made in the foregoing preferred embodiments without departing from the spirit and scope of the present invention, which is defined by the appended claims.