Patent Publication Number: US-2023142001-A1

Title: Cable Tray Fabricated from Curable Polymer Strips

Description:
BACKGROUND 
     Cable tray systems are a type of cable organizational management system used to support and route flexible transmission cables about an installation such as, for example, an industrial, commercial, and/or residential building. The flexible transmission cables may range from large diameter power cables, to smaller data transfer and communication cables, to small diameter fiber optics. The cable tray system is assembled from a plurality of cable tray units or sections that are interconnected together in a generally longitudinal arrangement to provide a rigid structural system for directing the flexible cables through the installation. The cable tray units are each in the shape of a basket or trough for accommodating the flexible cables such that the flexible cables extend or run through the interconnected basket-shaped cable tray units in an organized or bundled manner with running loose. 
     Typical cable tray units are formed as rigid structures constructed from, for example, metal sheets or interconnected rods meshed together. Typical metals include steel and aluminum. To maneuverably guide and route the path of the flexible cables through the installation, the cable tray units can be provided in different configurations including straight units or sections that are elongated linearly and elbow units or bend sections that are curved in shape to alter the direction of the cable paths. The different configurations of cable tray units can be selectively arranged and interconnected to route the flexible cables around obstacles such as structural support columns, ductwork, plumbing or the like. Because of the rigid, preconfigured nature of the cable tray units, preplanning and design is a prerequisite for installation of the cable tray system. The present disclosure is directed to a novel design for a cable tray system that improves flexibility and customization during installation of the system. 
     BRIEF SUMMARY 
     The disclosure relates to a cable tray and a method of fabricating cable trays for accommodating and directing a plurality of flexible transmission cables through an installation. The cable tray can be fabricated from soft solid curable polymer strip comprised of thermosetting polymer. Lengths of the soft solid curable polymer strip can be deployed on site from, for example, a strip roll and cut to length to form a pliable unformed rail section. The pliable unformed rail section may be molded and formed, by hand or using molding tools, to produce a pliable formed rail section to correspond to an intended configuration for the cable tray. Two pliable formed rail sections can be arranged juxtaposed to each other and connected together with a plurality of rungs. The thermosetting material can next be cured to produce two hardened rail section intercommoned by rungs in the form of a ladder type cable tray. 
     A possible advantage of the disclosure is the facilitation of onsite fabrication assembly and customized configuration of the cable trays. A possible related advantage is the disclosure facilitates the storage and transportation of the material for fabricating a cable tray. These and other advantages and feature of the disclosure will be apparent from the following detailed description and the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE. DRAWINGS 
         FIG.  1    is a perspective view of a cable tray system for routing flexible cables through an installation illustrating various configurations and shapes the cable trays may assume to change the direction or elevation of the cable tray system. 
         FIG.  2    is a perspective view of a wound roll of a soft solid curable polymer strip that may be unwound to deploy pliable unformed rail sections for fabricating a cable tray. 
         FIG.  3    is a perspective view of the soft solid curable polymer strip wound onto a strip spool that can be unreeled to deploy pliable unformed rail sections for fabricating a cable tray. 
         FIG.  4    is a flow chart illustrating a possible list of actions and steps for fabricating a cable tray system from soft solid curable polymer strips that may be formed and cured to produce hardened rail sections. 
         FIG.  5    is a perspective view of a first pliable formed rail section formed from the deployed first pliable unformed rail section (shown in dashed line) and a second pliable formed rail section formed from the deployed second pliable unformed rail section (shown in dashed lines). 
         FIG.  6    is an elevational view taken from the ends of a first pliable unformed rail section and a second pliable unformed section in a juxtaposed arrangement. 
         FIG.  7    is an elevational view similar to  FIG.  6    of the first pliable formed rail section and the second pliable formed rail section after being formed into structural channels, 
         FIG.  8    is a perspective view of the first pliable formed rail section and the second pliable formed rail section in a juxtaposed arrangement in an unassembled state. 
         FIG.  9    is a perspective view of the first pliable formed rail section and the second pliable formed rail section transversely connected together by a plurality of rungs, 
         FIG.  10    is a perspective view of a rung transversely connecting first and second formed rail sections with a dowel joint connection. 
         FIG.  11    is a cross-sectional view of a snap-fit connection for connecting the plurality of rungs transversely to one of the first and second pliable formed rail sections. 
         FIG.  12    is a perspective view of a curing process for fabricating a cable tray by polymerizing the first and second pliable formed rail sections into first and second hardened rail sections, 
         FIG.  13    is a perspective view of another embodiment in which the soft solid curable polymer strips may be provided as a plurality of semi-soft uncured rail planks arranged as a stack. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring generally to  FIG.  1    where, whenever possible, like reference numbers will refer to like elements, there is illustrated a cable tray system  100  that may be installed in a facility such as an industrial, commercial, or residential building. Cable tray systems  100  are used to support and route a plurality of flexible cables through the installation. The cable tray system  100  also typically elevates the plurality of flexible cables vertically above a lower floor to prevent interaction with water, dirt, etc. An elevated cable tray system  100  may be supported by vertically upright stanchions or suspended from hangers. As stated above, the cable tray systems  100  are often assembled from a plurality of cable tray units interconnected together. As referred to herein, the cable tray units individually or interconnected together may be commonly referred to as cable trays  102 . The cable trays  102  are designed to hold and contain the plurality of flexible cables together, rather than allowing the cables to hang loose, and to provide a route or pathway for the cables to extend along between their termination points. 
     While different styles of cable trays  102  are known in the art including, for example, solid bottom trays formed from steel sheets and wire mesh trays formed from interconnected metal rods, the present disclosure is particularly directed toward ladder cable trays  102 . Ladder cable trays  102  typically include a first elongated rail  104  and a second elongated rail  106  that are spaced apart from each other in a juxtaposed arrangement. The first and second elongated rails  104 ,  106  may be connected transversely by a plurality of rungs  108  that function to brace and maintain the first and second rails in the spaced-apart relation. In the longitudinal or lineal direction, the first and second elongate rails  104 ,  106  provide the continuous sides or edges of the cable tray  102  while the transverse rungs  108  that are intermittently spaced along the longitudinal or lineal direction provide horizontal support for the plurality of flexible cables. The elongated rails  104 ,  106  and the transverse rungs  108  provide an opened structure to facilitate installing or removing cables or rearranging or repairing cables. 
     To direct the plurality of cables around various obstacles at the facility or installation, such a structural supports, ductwork, and plumping, portions or sections of the cable trays  102  can have different configurations to change the direction of the cable tray system  100 . For example, if the flexible cables only need to extend between two points in a linear direction, the cable trays  102  can be configured as straight sections  110  that are directed in a linear or straight path. However, if flexible cables need to change direction, the cable trays  102  may be configured as a horizontal elbow  112  or bend that provides a curved path in the horizontal plane. The horizontal elbows  112  may be curved through any desired angle including, for example, 45° angles, 90° or right angles, and 180° or U-bends to reverse the directional path of flexible cables. In addition, it may be desirable to change the elevation of the flexible cables and the cable trays  102  can be configured as vertical elbows  114  that change the directional path to a different horizontal plane. The vertical elbows  114  can also be provided with angles of curvature. Furthermore, cable trays  102  can be configured to form different junctures such as T-junctures  116  and crosses  118  so that subsets of the plurality of flexible cables extending along the directional path associated with one cable tray can be routed to a different directional path associated with another cable tray. 
     Referring to  FIGS.  2  and  3   , the cable trays in accordance with the disclosure may be fabricated from soft solid curable polymer strips  120 . The soft solid curable polymer strip  120  can be comprised of a thermosetting polymer that is capable of being further cured to harden into a permanent shape with a greater rigidity and which is structurally self-supporting. The thermosetting polymer may be produced from a resin or prepolymer that includes a number of individual monomers which are molecules that can react with each other to form a polymer chain, for example, by cross-linking. In the process of polymerization, the thermosetting polymer gains structural rigidity and becomes a solid. Examples of suitable thermosetting polymers include polyester resins and vinyl ester resins, although any suitable thermosetting polymer can be used in accordance with the disclosure. 
     To facilitate fabrication of the cable tray system at the point installation, the thermosetting polymer that the rails is made of are provided as soft solid curable polymer strips  120 . A physical characteristic of a soft solid is that the curable polymer strip  120  is structurally, intact but is still in a pliable or malleable state to retain a degree of flexibility. In other words the constituent components of the soft solid curable polymer strips will not disassociated from each other and can be transported as a strip to the point of installation. Accordingly, the soft solid curable polymer strips  120  can be further worked or molded into a different or final desired shape. This enables the soft solid curable polymer strips  120  to be formed or shaped onsite into the configuration for the individual cable trays to selectively direct the flexible cables about the installation. The soft solid state can be obtained by partially curing the thermosetting polymer at the time it is molded into the shape of the soft solid curable polymer strips  120 . For example, the thermosetting polymer may be extruded into the soft solid curable polymer strips and partial curing may occur during extrusion. The partially cured soft solid curable polymer strips  120  can, after being molded into a final shape when fabricating the cable trays, be fully cured to harden into a solid structure. 
     The soft solid curable polymer strips  120  can be flattened elongate strips with a thin rectangular shape including a breadth  122  corresponding to width or height of the strip and a thickness  124  of a significantly smaller dimension than the breadth  122 . The soft solid curable polymer strips  120  may have any suitable length which may correspond to the longitudinal direction of the strip so that multiple rail sections can be cut from the same length of a soft solid curable polymer strip. To facilitate storage or transportation, the length of the soft solid curable polymer strips  120  can be wound into a spiral shaped strip roll  126  of a given diameter. Specially, the length of the soft solid curable polymer strip  120  can be circularly layered onto itself in spirals to produce the strip roll  126  that may be generally cylindrical. At the installation site, to form the rails, the desired length of the soft solid curable polymer strips  120  can be unwound from the strip roll  126 . The strip roll  126  may be wound or coiled as a standalone arrangement without a core or spool. In another example, the soft solid curable polymer strips  120  may be wound on a strip spool  128  or reel to hold the wound soft solid curable polymer strip together and to facilitate unreeling at the installation. 
     Referring to  FIG.  4   , there is a flow chart including possible steps or actions  130 - 148  for fabricating a cable tray from the wound soft solid curable polymer strips  120  at the point of installation. The flow chart is exemplary only and steps or actions may be added or removed during the fabrication process. To further explain the steps of the flow chart, the steps will be describes with reference to  FIGS.  5 ,  6 - 7 , and  8 - 9   . In an initial deployment step  130 , a desired length of the soft solid curable polymer strip  120  is deployed and cut or separated from the remaining length of the curable polymer strip  120 . In the examples where the soft solid curable polymer strips  120  are provided as wound strip rolls  126  or wound on a strip spool  128 , the deployment step  132  can involve unwinding or unreeling the need length of the soft solid curable polymer strip. 
     Referring to  FIG.  5   , when cut to the desired length, the soft solid curable polymer strip  120  becomes a first pliable unformed rail section  150 . Although still flexible, the first pliable unformed rail section  150  can have an associated first longitudinal extension  152  that corresponds to the length of the soft solid curable polymer strip  120  deployed. The longitudinal extension  152  can be appreciated when the first pliable unformed rail section  150  is linearly straightened or laid out as indicated by dashed lines in  FIG.  5   . 
     In a first forming operation  132 , the first pliable unformed rail section  150  can be worked or molded into a shape that corresponds with the configuration of the cable tray being fabricated. The retained flexibility of the first pliable unformed rail section  150  facilitates forming or molding during the forming operation  132 . Once formed or molded, the first pliable unformed rail section  150  becomes a first pliable formed rail section  154 , which may be indicated by the solid lines in  FIG.  5   . Prior to curing, the first pliable formed rail section  154  still retains flexibility but assumes a different or distinct shape. In an example, the forming operation  132  may including a first bending step  134  in which curvature is bent into the longitudinal extension  152 , The first bending step  134  can be conducted when, for example, forming a horizontal elbow  112  described in  FIG.  1    above. The curvature may be formed or imparted with respect to a center of curvature  156  and may be produced using molds or may be accomplished by hand. In a similar manner, the first bending step  134  may bend curvature into longitudinal extension  152  when forming the first pliable formed rail section  154  to produce a vertical elbow  114  described in  FIG.  1    above. 
     Because cable trays typically include two rails, a second deployment step  136  may be conducted in which another desired length of the soft solid curable polymer strip  120  is deployed and cut or separated from the remaining length to provide a second pliable unformed rail section  160 . The second pliable unformed rail section  160  may have or be associated with a second longitudinal extension  162 , which may be the same as or different than the first longitudinal extension  152  of the first pliable unformed rail section  150 . A second forming operation  138  can be conducted in which the second pliable unformed rail section  160  is formed or molded into a different shape, facilitated by the retained flexibility of the thermosetting material, to produce a second pliable formed rail section  164 . The second pliable formed rail section  164  may correspond in shape with the first pliable formed rail section  154 . When forming a cable tray configured as a horizontal bend, for example, the second forming operation  138  may include a bending step  140  in which curvature is imparted into the longitudinal extension  162  of the second pliable formed rail section  164  to produce a curved shaped which may share the center of curvature  156 . It can be appreciated that when configuring a horizontal elbow from the first and second pliable formed rail sections  154 ,  164 , the dimensions of the respective longitudinal extensions  152 ,  162  should be different. 
     In an arrangement operation  142 , the first pliable formed rail section  154  and the second pliable formed rail section  164  may be arranged in a spaced-apart juxtaposed relation. In an example, the first and second pliable formed rail sections  154 ,  164  may be parallel to each other and may be spaced-apart a consistent distance over their longitudinal extensions as illustrated in  FIG.  5   . However, in other examples, the first and second pliable formed rail sections  154 ,  164  may diverge or converge with respect to each other while still being juxtaposed side-by-side. Diverging or converging the first and second pliable formed rail sections  154 ,  164  may occur, for example, when fabricating the cable tray having an expander configuration or a reducer configuration wherein the width or breadth of the cable tray changes to accommodate more or fewer individual flexible cables. 
     In an embodiment, the first and second pliable formed rail sections  154 ,  164  may be formed as structural channels to increase the rigidity or stiffness of the fabricated rails. Referring to  FIGS.  6  and  7   , there is illustrated a possible channeling step  144  which may be part of the first and second forming operations  132 ,  138  during forming or molding of the first and second pliable unformed rail sections  150 ,  160 . The first and second pliable unformed rail sections  150 ,  160  may have or be associated with corresponding first and second breadths  122  that corresponds with the width or height of the pliable unformed rail sections and which is orthogonal to first and second elongated extensions  152 ,  162  associated with those sections. In an example, when deployed, the first and second pliable unformed rail sections  150 ,  160  may be flat and linear and the breaths  122  may correspond to the straight linear width or height of the pliable unformed rail sections. 
     However, in another example, to facilitate the channeling operation  144  the first and second pliable unformed rail sections  150 ,  160  may include a preformed flexure  170  disposed into the respective breadths  122  and which extends lineally along the longitudinal extension  152 ,  162  of the respective pliable unformed rail section. The flexure  170  can be formed when the soft solid curable polymer strip  120  is extruded. The flexure  170  imparts flexibility into the breath  122  of the first and second pliable unformed rail sections  150 ,  160  that allows them to be complaint and bend in specific directions. The flexures  170  segment or define respective first and second distal wings  172 ,  174  into each to the breaths  122  of the respective pliable unformed rail sections  150 ,  160 . The distal wings  172 ,  174  may extend at an angle with respect to the rest of the breath  122  of the respective pliable unformed rail sections  150 ,  160 , which may be angled by only a few degrees from the orientation of the breadths. 
     During the channeling operation  144 , the distal wings  172 ,  174  are displaced or angled so that the distal wings are normal or perpendicular to the rest of the breath  122  of the partially formed first and second pliable formed rail sections  154 ,  164 . The first and second pliable formed rail sections  154 ,  164  assume the shape of a structural channel  176  such as U-channel or C-channel in which the first and second distal wings  172 ,  174  function as flanges and the remaining breadth  122  of the first and second pliable formed rail sections  154 ,  164  is a web joining the flanges. Molding or shaping the first and second pliable formed rail sections  154 ,  164  as structural channels  176  with integral orthogonal flanges and a web resists bending moments that may be experienced by the the finished fabricated rails. 
     In a connection step  146 , the first pliable formed rail section  154  and the second pliable formed rail section  164  in the juxtaposed arrangement can be connected together with a plurality of rungs  108 . For example, referring to  FIGS.  8  and  9   , the first and second pliable formed rail sections  154 ,  164  may be spaced apart from each other and, in an example, may be parallel to each other. Further, when the first and second pliable formed rail sections  154 ,  164  are formed as structural channels  176 , they may be juxtaposed in a facing or opposed relation. The plurality of rungs  108  may also be made of a thermoplastic material but, unlike the first and second pliable formed rail sections  154 ,  164 , the rungs  108  may be fully cured and rigid at the time of connection. In other examples, the plurality of rungs  108  may be made from other suitable materials. The plurality of rungs  108  may be disposed between the juxtaposed first and second pliable formed rail sections  154 ,  164  to transverse the spaced-apart distance between the pliable formed rail sections. The plurality of rungs  108  can be connected or secured to each of the first and second pliable formed rail sections  154 ,  164  by any suitable connection method. For example, the rung ends  180  of each of the plurality of rungs  108  can be formed as a bifurcated clamp and can receive and be clamped to one of the first or second distal wings  172 ,  174  of each of the first and second pliable formed rail sections. To securely fix the plurality of rungs  108  to the respective first or second distal wings  172 ,  174 , threaded fasteners  182  such as bolts and nuts or possibly rivets can be inserted through the rung ends  180  and the distal wings  172 ,  174  to affix the structures together. In addition, various types of brackets and supports can be used to affix the rungs  108  to the distal wings  172 ,  174  of the first and second pliable formed rail sections  154 ,  164 . The plurality of rungs  108  thereby transversely connect the juxtaposed first and second pliable formed rail sections  154 ,  164  to brace and maintain their spaced-apart relation. Arrangement and fabrication of the first and second pliable formed rail sections  154 ,  164  transversely connected by the plurality of rungs  108  thus far assumes the arrangement of a ladder type cable tray  102 . 
     Referring to  FIGS.  10  and  11   , there are illustrated additional connection techniques for affixing the plurality of rungs  108  transversely between the first and second pliable formed rail sections  154 ,  164 . In  FIG.  10   , the plurality of rungs  108  may be each shaped as cylindrical rods with a circular outer diameter and may be cut to the axial length corresponding to the spaced-apart distance that should be maintained between the first and second pliable formed rail sections  154 ,  164  once the cable tray is fabricated and installed. In an example, the individual rods corresponding to the plurality of rungs  108  may be cut onsite at the installation site from a longer rod provided with the soft solid curable polymer strip so that the spaced-apart distance between first and second pliable formed rail sections  154 ,  164 , corresponding to the width of the cable trays, can be customized onsite. 
     Disposed into the first and second pliable formed rail sections  154 ,  164 , preferably aligned toward the ends of the breaths  122 , of the first and second pliable formed rail sections  154 ,  164 , can be a plurality of dowel holes  184 . The diameter of the dowel holes  184  can match the diameters of the plurality of rungs  108  so that the rung ends  180  can be press fit into the plurality of dowel holes  184 , thereby securing the plurality of rungs to the first and second pliable formed rail sections  154 ,  164 . Press fitting the rung ends  180  into the plurality of dowel holes  184  may be aided by the pliability of the first and second pliable formed rail sections  154 ,  164 . The plurality of dowel holes  184  can be formed during extrusion, deployment or forming of the first and second pliable formed rail sections  154 ,  164 . 
     Referring to  FIG.  11   , there is illustrated an example where the connection between plurality of rungs  108  and the first and second pliable formed rail sections  154 ,  164  is designed as an annular snap-fit connection. The rung ends  180  can be formed with an axial protrusion  190  smaller in diameter that the rungs  108  and that has an annular shoulder  192  extending about the circumference of the axial protrusion. Disposed into the breaths of the first and second pliable formed rail sections  154 ,  164  can be a corresponding cylindrical cavity  194  dimensioned to receive the axial protrusion  190  and with an annular groove  196  that extends circumferentially outward of the cylindrical cavity. When the axial protrusion  190  is inserted into the cylindrical cavity  194 , the annular shoulder  192  can be received in and interlock with the annular groove  194  locking the structures together. The pliability of the first and second pliable formed rail sections  154 ,  164  allows the material of these structures to deflect facilitating the interlocking of the snap fit connection. 
     In a curing step  148 , the thermosetting polymer of the first and second pliable formed rail sections  154 ,  164  is fully cured to molecularly polymerize and structurally harden them into a respective first hardened rail section and a second hardened rail section. Referring to  FIG.  12   , there is illustrated an example by which the thermosetting material may be cured to fabricate the first hardened rail section  200  and the second hardened rail section  202 . The thermosetting polymer that is the initial starting material of the first and second hardened rail sections  200 ,  202  may be a photopolymer that reacts and changes its physical properties upon exposure to electromagnetic radiation, particularly ultraviolet light or visible light. Exposure to light radiation completes the curing process by which the monomers in the photopolymer material continue cross-linking to complete the polymerized chains. This increases the rigidity of the polymer material to result in a hardened solid, for example, the first and second hardened rail sections  200 ,  202 . The hardened first hardened rail section and a second hardened rail sections  200 ,  202  are no longer flexible and will retain the definite shape and configuration molded by the first and second forming operations  132 ,  136  conducted previously. The first hardened rail section  200  may correspond to the first rail  104  and the second hardened rail section may correspond to the second rail section  106  of the cable tray  102 . 
     An advantage of the photo-curing process is that it can be done at the installation site using a ultraviolet (UV) or visible light source  204  such as a lamp after the first and second pliable formed rail sections  154 ,  164  have be molded, formed, and arranged juxtaposed with each other braced in the spaced-apart relation by the plurality of rungs  108 . The light source  204  can be focused on and directed along the longitudinal extension of each of the pliable formed rail sections producing the corresponding first and second hardened rail sections  200 ,  202 . The resulting fabrication is a structurally fixed cable tray  102  of the desired configuration including a first rail  104  and a second rail  106  spaced apart by a plurality of transverse flings  108 . 
     In an example, to facilitate onsite fabrication of the cable trays  102  during installation of the cable tray system, various components and structures described herein can be provided together as a kit. For example, the kit may include a length of the soft solid curable polymer strip  120 , which may be provided as a strip roll  126  or wound onto a strip spool  128 , and a light source  204  for curing the first and second pliable formed rail sections  154 ,  164  cut and formed from the soft solid curable polymer strip  120 . 
     Referring to  FIG.  13   , there is illustrated another example of the soft solid curable polymer strips  120  from which the cable trays can be fabricated. In the illustrated example, the curable polymer strips  120  can be provided in the form of a plurality of soft solid curable polymer planks  210  that are elongated and linearly straight in shape. Moreover, a plurality of the soft solid curable polymer planks  210  may be arranged in a stack  212  to facilitate storage and transportation to the installation site. In the illustrated example, the soft solid curable polymer planks  210  may be partially formed as structural channels, for example, C-channels or U-channels, during an extrusion process. The partially formed curable polymer planks  210 , however, may retain flexibility or pliability for subsequent forming and molding operations. The shape of the structural channels enables them to be placed together in a superimposed relationship that reduces the bulk of the stack  212 . At the installation site, the individual soft solid curable polymer planks  210  can be deployed from the stack, cut to length, and molded or formed into the necessary shape, for example, by bending curvature into the longitudinal extension of the curable polymer blank, to fabricate cable trays in the configuration of a horizontal or vertical elbow. The curing operation  138  described above can be conducted to finish fabricating the hardened and rigid cable tray of the desired configuration. 
     The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. 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.