Patent Publication Number: US-2023148161-A1

Title: Cable Tray

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to Canadian Patent Application No. 3,138,070, filed on Nov. 8, 2021, which is incorporated herein in its entirety by reference. 
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to systems and devices for supporting cables, in particular, cable trays for supporting electrical and other types of conduits. 
     BACKGROUND 
     Cable trays are used in buildings and other structures for supporting cables and other conduits. In modern facilities, where it is less common to run cables and the like inside of building walls, cable trays are useful in organizing and routing electrical power, signal, other cables, and other conduits such as tubing and piping, for example. Cable trays are configured to support the running of cables throughout a facility and are typically attached to walls or suspended from ceilings of the facility in order to provide easy access to the cables while keeping them from interfering with operations within the facility. 
     In commercial facilities, designed for manufacturing for example, the combined weight of electrical and signal cables and other conduits can be substantial. While cable trays must be able to support the weight of cables that they carry, it would be desirable to do so without using unnecessarily costly amounts of material in constructing the trays. There is a need for an improved construction of cable trays. Devices and methods according to the disclosure satisfy the need. 
     The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     Aspects of the disclosure include a pair of opposed side rails. Each of the pair of side rails includes an upper flange and a lower flange. A web portion extends between and interconnects the upper flange and the lower flange. The web portion includes an outer side and an inner side and a plurality of stiffeners protrude one or more of inwardly and outwardly therefrom. A plurality of spaced apart rungs extend between and connect the pair of opposed side rails. 
     Another aspect of the disclosure includes a method of making a cable tray, which includes forming a plurality of rungs, forming a pair of rails, each of the rails having an upper flange, a lower flange, and a web portion extending between and interconnecting the upper flange and the lower flange. The web portion includes an outer side and an inner side. A plurality of stiffeners are formed in the web portion. The plurality of rungs are interposed between the pair of rails and the rungs are connected to the pair of rails to form the tray. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    is a perspective view of conventional cable tray. 
         FIG.  2    is a perspective view of a cable tray according to the disclosure with convexities. 
         FIG.  3    is a side view of the cable tray of  FIG.  2   . 
         FIG.  4    is an end view of the cable tray of  FIG.  2   . 
         FIGS.  5 - 15    are perspective views of cable trays with alternative embossments. 
         FIG.  16    is a perspective view of a cable tray according to the disclosure with corrugated flanges. 
         FIG.  17    is a cross section view of an embodiment of the flange of  FIG.  16   . 
         FIG.  18    is a flowchart illustrating a method of making a cable tray. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in the figures. Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings. Use of the term “configured” is intended to refer to the shape and size of a structural element. 
     Where possible, any terms expressed in the singular form herein are meant to also include the plural form and vice versa, unless explicitly stated otherwise. Also, as used herein, the term “a” and/or “an” shall mean “one or more” even though the phrase “one or more” is also used herein. Furthermore, when it is said herein that something is “based on” something else, it may be based on one or more other things as well. In other words, unless expressly indicated otherwise, as used herein “based on” means “based at least in part on” or “based at least partially on”. 
       FIG.  1    shows a conventional cable tray  20 , which includes a ladder-like configuration, with two opposed, parallel and elongate rails  22  that are interconnected via a plurality of spaced apart rungs  24 . The rungs  24  are typically oriented transversely relative to the rails and normal to the longitudinal axis “A” of the tray  20 . The rungs  24  may be cylindrical, square, rectangular, or any suitable shape. Typically, the rungs are welded to the rails, but other methods of attachment are known including the use of clips, as is known. It will be understood that the following figures will illustrate only portions of the same basic cable tray, with modifications to aspects thereof from that shown in  FIG.  1   . For clarity, every alternative will not be shown in a complete cable tray assembly, and it will be understood that such modified parts are substituted for those general elements appearing in  FIG.  1   . 
     Each of the rails  22  includes an upper flange  26  and a lower flange  28 . The flanges  26 ,  28  are interconnected by and spaced apart by a web  30 . Typically, the flanges  26 ,  28  are oriented in a generally horizontal plane when the cable tray  20  is installed in a facility and typically extend inwardly and outwardly from the web  30 , which is oriented in a generally vertical plane. Both flanges  26 ,  28  are generally planar, rectangular plates, made of any suitable material, such as steel, aluminum, or other metallic materials, and plated/coated metals, or, in the alternative, composites such as fiberglass. It is more common, however, that the material forming the tray  20  is electrically conductive so that the tray can be grounded. The web  30  of each of the rails  22  is a planar, rectangular plate and may be made of the same material or materials as the flanges. The web  30  may be a solid piece, uninterrupted by openings with exceptions being made for means to join trays together with fasteners, for example, or for ventilation or other functionality. 
     Each rail  22  therefore includes a pair of spaced flanges  26 ,  28  interconnected by a web  30  extending therebetween. The rails  22  may be extruded or otherwise formed as a one-piece construction or formed as separate pieces by extrusion or rolling, for example, and joined together by welding, for example. Commonly, cable trays  20  are manufactured in lengths which are joined together to form long runs or cut to desired lengths to form a desired configuration for a specified installation. 
       FIGS.  2 - 4    show a rail  32  for a cable tray that has been modified from that shown in  FIG.  1    to provide an increase in resistance to torsional forces resulting from loading the cable tray. Due to the construction of cable trays  20 , each rail  32  tends to respond to loading by twisting inwardly. A deflection including such a twist is known as torsion. As a result of the modification illustrated in  FIGS.  2 - 4   , and the following alternatives, to the shape of the web portion  34  of the rail  32 , which increases resistance to torsion, less material can be used in the web portion  34 . In this example, all other features of a cable tray remain unchanged and only the web portion  34  is modified from the original configuration. 
     In this embodiment, the rail  32 , including an initially generally flat web portion  34 , may be formed by extrusion or any suitable method such as roll forming, laser cutting, punching, hydroforming, bending, and so on. Subsequently, after initial forming of a blank or work piece, the rail  32  is placed in or passed through a die or otherwise formed into the final configuration shown. The cold forming process may involve a single cold forming operation or may involve progressive methods. Similar methods may be employed in making all of the embodiments disclosed herein including the rungs and flanges. 
     The rail  32 , after forming, is provided with a plurality of stiffeners  40  arranged with a main axis oriented generally vertically in the web. Alternatively, the stiffeners  40  may be inclined from the vertical orientation. Each of the stiffeners  40  has a shape including a semi-cylinder portion  41  with rounded ends  42  and a length (L) that spans more than half the distance between the flanges  26 ,  28 . In embodiments, the length L is about 90 percent of the distance between the flanges  26 ,  28 . In one example, where the rail  32  is about seven inches in height (H), the stiffeners  40  are about six inches in length L, about one inch in diameter (D) and the rounded transitions  42  at the end and sides of the stiffeners have a radius (R) of about ½ inch. In embodiments, the radius R of the semi-cylinder portion  41  is about ½ inch. In embodiments, the stiffeners have a height from about 40% to about 95% that of the web. In embodiments, the height H of the rail  32  is from about two inches to about eight inches. 
     In the illustrated rail  32 , all of the stiffeners  40  protrude only from an outer side  46  of the web portion  34  as best seen in  FIG.  4   . While forming stiffeners to protrude from the inner side  44  is also contemplated or both sides, it is believed that a greater stiffening effect may be realized from forming the stiffeners  40  to protrude from the outer side  46 . 
     Furthermore, for purposes of the disclosure, reference to a feature or element protruding from the outer side or inner side will be used to refer to a stiffener or parts of a stiffener that has structural aspects that extend in a direction relative to the plane of the generally flat or planar portion of the web  34 . It will be understood, that stiffeners  40 , and all of the embodiments of stiffeners disclosed herein are features that are formed from original web material, not material that is added to the original material of the web. Accordingly, the stiffeners  40 , and all of the stiffeners disclosed herein have a concave or negative side  43  and a corresponding convex or positive side  45 . In the instant embodiment of  FIGS.  2 - 4   , stiffeners  40  have a convex, positive extending rib shape extending outwardly from the outer side  46  and a corresponding concave, negative extending rib shape formed in the inner side  44  of the web  34 . 
     As shown in  FIG.  5   , stiffeners  40  may be formed to protrude from both the outer and inner side  46 ,  44 . The stiffeners  40  may be spaced apart from each other longitudinally a distance (d) from about two to about three inches. The stiffeners  40  may also protrude from the plane of the web  34  about ½ inch. It will be understood that other spacing and dimensions of the stiffeners  40  are contemplated. In  FIG.  5    stiffeners  40 A protruding from outer side  46  are formed on the web  34  alternatingly with stiffeners  40 B which protrude from the inner side  44  of rail  48 . Other patterns are contemplated. 
       FIG.  6    and  FIG.  7    show stiffeners  50  that are generally rectangular and have a greater diameter D relative to the stiffeners of  FIGS.  2 - 5   . For orientation, the upper and lower flanges  26 ,  28  are shown. The sides of the rectangular stiffeners  50  meet at corners  42  with, for example, a ½ radius R. The same radius R extends around the entire shape of each of the stiffeners  50  to define a central, rectangular planar surface  51 . The stiffeners  50  may be more than one inch in diameter D, for example, from about two inches to about three inches in diameter. All of the stiffeners  50  in  FIG.  6    protrude from the outer side  46  of the web  34 . In contrast, the stiffeners  50 A,  50 B of  FIG.  7   , while having the same size and shape as those stiffeners  50  of  FIG.  5   , protrude alternatingly from the outer side  46  and the inner side  44  along the length of the web  34 . The length L of the stiffeners  50 A,  50 B may be the same or similar to the length of the stiffeners of  FIG.  3   , for example. 
       FIG.  8    and  FIG.  9    show stiffeners  52  that are generally triangular with corners  54  and straight sides  56  rounded with a radius R of about ½ inch. The shape of the triangles may be that of an isosceles triangle. The stiffeners  52  have a base diameter D or base segment length and a length L similar to the stiffeners of  FIG.  7   . The stiffeners  52  may be from about two inches to about three inches in diameter D at the base of the triangle  58 . A central, triangular planar surface  60  of each of the stiffeners  52  is defined between the base  58  and sides  56 . The stiffeners  52  alternate in orientation with a first stiffener having its base  58  positioned adjacent the upper flange  26  and a second, adjacent stiffener  52  with its base  58  positioned adjacent the lower flange  28  and so on. 
     All of the stiffeners  52  in  FIG.  8    protrude from the outer side  46  of the web  34 . In contrast, the stiffeners  52 A,  52 B of  FIG.  9   , while having the same size and shape as those stiffeners  52  of  FIG.  7   , protrude alternatingly from the outer side  46  and the inner side  44 .  FIG.  10    shows stiffeners  52  which are the same in size and shape as those shown in  FIG.  8   , however all of the stiffeners  52  in  FIG.  10    have base  58  positioned adjacent the upper flange  26 . 
       FIG.  11    includes stiffeners  62  which are arranged in web  34  in two rows. A first row  64  is positioned adjacent the lower flange  28  and below the second row  66  which is positioned adjacent the upper flange  26 . Each of the rows  64 ,  66  includes triangular stiffeners  62  that protrude from the outer side  46 . It will be understood that forming the stiffeners  62  to alternate in the direction of protrusion from the outer side  46  and the inner side  44  of the web  34  is contemplated as well as other patterns. To fit the stiffeners  62  into the two rows, the size of each stiffener may be about half that of the stiffeners that are sized to span most of the distance from the upper to the lower flange  26 ,  28  as is shown in  FIG.  8   , for example. In the illustrated example, adjacent stiffeners  62  in the first and second rows  64 ,  66  may be arranged as mirror opposites. It will be understood that the present disclosure contemplates any of the shapes of stiffeners arranged in one, two, or more horizontal rows. 
       FIG.  12    shows a set of circular stiffeners  70  arranged in a web  34  of rail  72 . Stiffeners  70  have a vertical length L that may be equal to the horizontal diameter D. Accordingly, the stiffeners  70  are spaced apart so that there is web material  34  between each of the stiffeners, i.e., more than about seven inches apart center-to-center for example. Each of the stiffeners  70  includes a radius R of about ½ inch defining the outer edge  71  of the stiffener to form a flat annular panel  74  that protrudes relative the web portion  34  from the outer side  46 . Inside the flat annular panel  74  is a radius R that is positioned at the inner edge  73  of the panel  74  and defines a circular panel  76  that protrudes inwardly relative to the flat annular panel  74 . 
       FIG.  13    shows a set of circular stiffeners  80  that are alike in size and shape to those shown in  FIG.  12    except the material of the circular panel of  FIG.  12    has been removed to provide a circular aperture  82 . The circular aperture  82  may promote air circulation and lightens the weight of the rail  84 . 
       FIG.  14    shows a set of circular stiffeners  90  that are alike in size and shape to those shown in  FIG.  13    except the material of the annular panel of  FIG.  12    has been removed to provide a circular aperture  92 . The circular opening  84  may promote air circulation and lightens the weight of the rail  94 . 
       FIG.  15    shows a set of circular stiffeners  100  that are alike in size and shape to those shown in  FIG.  14    except material extends from the radius R defining the outer edge  106  of the stiffener  100  inwardly to form an annular panel  102  with an aperture  104  formed at the center thereof. The opening  104  permits airflow and lessens the weight of the rail  108 . It can be seen from the foregoing that protrusions of the rail web material that deviates from the plane of the web can function as stiffening features and may have a variety of geometric shapes, sizes, and orientations. 
     Turning to  FIG.  16   , a rail  110  is shown that has stiffening elements  40 A,  40 B from the embodiment described in connection with  FIG.  5    formed in web  34 . The upper flange  126  and lower flange  128  are formed with corrugations  130  to provide additional stiffening. The corrugations  130  may be formed by extruding the flanges  126 ,  128  or by passing a flat, featureless plate of material through a roller or other cold forming process. After forming the corrugations  130 , the flanges  126 ,  128  may be welded to the web  34  to form a complete rail  110 . 
     In cross section as seen in  FIG.  17   , the upper and lower flanges  126 ,  128  may be formed of a series of generally trapezoidal segments  130 ,  132 ,  134 ,  136  and so on joined at edges thereof to form a corrugated configuration. The corrugated configuration, i.e., the arrangement of the segments  130 ,  132 ,  134 ,  136  may form alternating ridges and grooves. The corrugated configuration may include bead ribs, pencil ribs, sine wave shapes, v-ribs, striated, fluted, and other alternating shapes, and combinations thereof. In the illustrated embodiment, a first one of the segments  130  is joined to a second one  132  of the segments such that the second segment  132  is positioned out of the plane of the first segment and closer to the web  34 . The third segment  134  which is joined to the second segment  32 , is positioned in the plane of the first segment  130 . The fourth segment  136  is joined to the third segment  132  in the plane of the second segment  132  and so on. In embodiments, there are 13 segments that the upper flange  126  and 13 segments that form the lower flange  128 . Other numbers of corrugations are contemplated. 
     Methods of making a cable tray according to the disclosure are set out in  FIG.  18   . Also referring to  FIGS.  1 - 17   , rungs  24  are formed by extrusion or cold forming in step  140 . The rungs may begin as an elongate extrusion that is subsequently cut into desired lengths. In step  142  a web blank or work-piece is formed by extrusion or cold forming and is modified by cold forming to form a plurality of stiffeners (one or more of 40, 42, 50 60, 70, 80, 90, 100) on the web  34 . The cold forming may include placing the work piece into a flat die and stamping or passing the work piece through a set of correspondingly configured rollers that include the positive and negative shapes for producing the desired shape and spacing of stiffener features in the work piece. In an optional step  144 , apertures (one or more of 82 92, 104) are formed in the web to remove material from the area of the web, including those areas with stiffeners. In step  146 , upper and lower flanges (26, 28, 126, 128) are formed by extrusion or cold forming, for example, and are attached to the web  34  to form a rail (one or more of 32, 48, 72, 84, 94, 108, 110). Two rails (32, 48, 72, 84, 94, 108, 110) are attached to each other by attaching a plurality of rungs  24  therebetween by welding or any suitable method in step  148 . 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.