Patent Publication Number: US-2009217594-A1

Title: Modular panel gate assembly for a cantilever slide gate system

Description:
BACKGROUND 
     1. Field 
     The presently disclosed subject matter relates to devices, systems, and processes useful as sliding gates, and more specifically to a modular panel gate assembly that can provide customizable gate lengths from mass-production components. 
     2. Description of the Related Art 
     There are many security gate configurations currently in use to permit vehicular and/or pedestrian access to a commercial/industrial or other site secured by a perimeter or other fence. One configuration is a cantilever slide gate in which one section of the gate is supported above the ground between two support post assemblies and another portion of the gate extends across the opening in the security fence when the gate is in the closed position. U.S. Pat. No. 4,723,374 to Peterson discloses a typical slide gate system, and is incorporated herein by reference. 
       FIG. 1  illustrates a cantilever slide gate system  200 . The cantilever slide gate system  200  includes a gate  202  vertically suspended above the ground by a plurality of support post assemblies  204  (only one is shown). The support post assemblies  204  support the weight of the gate  202  and cooperate with the gate  202  to guide the gate  202  between the closed position and the opened position. 
     The gate  202  includes a top primary member  206 , a track member  208 , a lower tube member  210 , and a plurality of vertical members  212  (only one is illustrated). The top primary member  206 , the lower tube member  210 , and the track member  208  are shown in cross-section in  FIG. 1 . The vertical members  212  extend between and are connected to the top primary member  206  and the lower tube member  210 , for example, by stitch welding. The track member  208  is also secured to the top primary member  206  by stitch welds. 
     In order to properly align the track member  208  with the top primary member  206 , the top primary member  206  includes a keyway  214  and the track member  208  includes a key  216 . The track member  208  also includes a horizontal flange  218  that extends across a top external surface  220  of the top primary member  206  and a vertical flange  220  that extends along a side surface (not numbered) of the top primary member  206 . The track member  208  includes an inner surface (not numbered) that defines a track that is configured to receive a truck  224  of a hanger assembly  226  from which the gate  202  is suspended. The vertical flange  222  extends from the track member  298  below the track (not numbered). The key  216  is positioned at a location intermediate the track (not numbered) and the vertical flange  222 . 
     Each support post assembly  204  includes a support post  228 , a lower guide assembly  230 , and the above-described hanger assembly  226 . The hanger assembly  226  includes the truck  224  and a hanger bracket  232  secured to the truck  224 . The hanger bracket  232  is secured to the support post  228  by a plurality of U-bolts  234 . The lower guide assembly  230  is secured to the support post  228  by a U-bolt  236 . 
     The truck  224  includes a pair of horizontal rollers  238  (only one is visible in  FIG. 1 ) and four vertical rollers  240  (only two are visible in  FIG. 1 ). The horizontal rollers  238  engage the inner side walls (not numbered) of the track (not numbered) and the vertical rollers  240  engage the upper and lower surfaces (not numbered) of the track (not numbered). Thus, the hanger assembly  224  and the track member  208  cooperate to support the gate  202  above the ground as the gate  202  moves between the closed position and the open position. 
     The lower guide assembly  230  engages the sides (not numbered) of lower tube member  210  to limit horizontal displacement of the gate  202  toward and away from the support post  228  as the gate  202  moves between the closed position and the opened position. 
     Existing cantilever sliding gate systems are typically custom built to meet dimensional requirements specific to each customer. That is, the top primary member  206  and the lower tube member  210  are each made from a single extruded blank that has a length equal to the length required by the end user for the gate  202 . In some cases, for a very long section, the track and top primary member can be spliced at alternating locations. Specifically, the track and the top primary member can be located relative to each other so that each track member overlaps two top primary members, and vice versa, and are then joined by welds or other attachment structures. This type of overlap splice provides greater strength when the gate is assembled. 
     However, custom built sliding gate systems can be labor intensive, can take a long period of time from order to delivery, and can be costly to manufacture and ship to the end user. 
     Modular systems can reap the benefits of mass production volumes while also permitting designed-in versatility for customization for each end user. The gate modules can be sized to meet standard shipping requirements. Thus, modular sliding gate systems can provide economies of scale from mass-production and significantly reduce shipping and installation cost per gate. In addition, certain strength and operation benefits can be achieved by a modular system. 
     However, many of the existing and prior modular sliding gate systems might not meet certain ASTM and other industry guidelines. In addition, many of these prior attempts at modular sliding gate systems might not meet customer demands for long-term performance, durability, ease of assembly, etc. 
     SUMMARY 
     According to one aspect of the disclosure a modular slide gate is movable along a hanger assembly of a cantilever slide gate system between an open position where access through a secured perimeter is permitted and a closed position where access through a secured perimeter is obstructed. The modular slide gate can include a top member, a bottom member, and a plurality of cross members extending between and connected to the bottom member and the at least one wall of the frame member. The top member can include a frame member and a track member. The frame member can include at least one wall. The track member can be configured and dimensioned to receive the hanger assembly and can include at least one wall that extends continuously from and is homogenous with the at least one wall of the frame member. 
     According to an aspect of the disclosed subject matter, a modular panel gate assembly for a cantilever slide panel gate system can include a support assembly and a hanger assembly secured to the support assembly. The support assembly can suspend the modular gate panel assembly in a cantilevered manner as the modular panel gate assembly moves along the hanger assembly between a closed position where the modular gate panel assembly can obstruct access through an opening in a secured perimeter and an opened position where the modular panel gate assembly can permit access through the opening in the secured perimeter. The modular panel gate assembly can include a first gate panel and a second gate panel. The first gate panel can be disengageable from support assembly and the hanger assembly when the modular panel gate assembly is in the closed position and engageable with the support assembly and the hanger assembly when the modular gate panel assembly is in the opened position. The first gate panel can include a first top member, a first bottom member, and a plurality of cross members. The top member can include a first frame member and a first track member. The first track member can be secured to and extend from the first frame member. The first track member can be configured and dimensioned to receive the hanger assembly. The first bottom member can extend parallel to the first top member. The first plurality of cross members can extend between and connect to the first bottom member and the first frame member. The second gate panel can be engageable with the support assembly and the hanger assembly when the modular panel gate assembly is in the closed position and disengageable with the support assembly and the hanger assembly when the modular gate panel assembly is in the opened position. The second gate panel can include a second top member, a second bottom that can extend parallel to the top member, a second plurality of cross members that can extend between and connect to the second bottom member and the second frame member. The second top member can include a second frame member and a second track member. The second track member can be secured to and extend from the second frame member. The second track member can be configured and dimensioned to receive the hanger assembly. A first connector can be secured to the first and second frame member, a second connector can be secured to the first and second bottom members, and a third connector can be secured to the first and second track members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given by way of example, and with reference to the accompanying drawings, in which: 
         FIG. 1  illustrates a commercially available cantilever sliding gate that is of a customized one-piece design. 
         FIG. 2  is a perspective view of an embodiment of a modular cantilever sliding gate system in accordance with the disclosed subject matter. 
         FIG. 3  is a cross-sectional view taken along A-A of  FIG. 2 . 
         FIG. 4  is an exploded perspective view of the abutting portions of two gate panels of the modular cantilever sliding gate system of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 2  illustrates a modular cantilever slide panel gate system  10 . The system  10  can include a modular panel gate assembly  12 , two support post assemblies  14 , and a catcher assembly  16 . Each support post assembly  14  can include a hanger assembly  18  and a lower guide assembly  20  (see  FIG. 1  for details) which support the modular panel gate assembly  12  in a cantilevered configuration and guide the modular gate panel assembly  12  as the modular panel gate assembly  12  moves between the closed position and the opened position. 
     The modular panel gate assembly  12  can include a first panel  22  and a second panel  24 . The panels  22 ,  24  can be secured to one another along a joint  26 . (Details of the joining of the panels  22 ,  24  will be discussed below.) Each panel  22 ,  24  can have the same length dimensions, as shown in  FIG. 2 , or one panel can have a length different from the other panel. For example, the first panel  22  can have a length of 18 feet and the second panel  24  can have a length of 12 feet. Alternatively, two 18 foot panels, two 12 foot panels, or a single panel of either 12 feet or 18 feet may be used. This dimensional flexibility can permit customization of the modular panel gate assembly  12  to fit gate openings ranging from 8 to 25 feet by the manufacture and assembly of only two different panel sizes as compared to a customized gate panel which must be manufactured individually for each gate opening size specified by the end user. Of course, other “standard” size and “standard” dimensions can be used for each of the modular gate panels  22 ,  24  without departing from the spirit and scope of the disclosed subject matter. In addition, three or more panels could be used for certain applications of the disclosed subject matter. The disclosed gate can facilitate quick and easy replacement of each of the modular gate panels. For example, if one gate panel is destroyed or broken, a modular replacement can be put in place right away. This achieved by either the user ordering additional modular panels and having them on site, or ensuring that a distributor in the area stock the modular gate panels. Thus, a custom repair is not necessary, and the time of any security breach caused by a defective gate can be minimized. 
     As shown in  FIGS. 2 and 4 , each panel  22 ,  24  can be structurally identical. It should be understood that although only two panels  22 ,  24  are shown, the use of three or more panels would also be consistent with and is contemplated as being part of the disclosed subject matter. In addition, the panels need not be identical, but can vary in shape and size dramatically. Each of the panels  22 ,  24  can include a top member  26 ,  28 , a bottom member  30 ,  32 , first exterior cross members  34 ,  36 , second exterior cross members  38 ,  40  (only the second exterior cross member  38  of the first panel  22  and the first cross member  36  of the second panel  24  are shown in  FIG. 4 ), a plurality of interior vertical members  42  ( FIG. 2  only), a plurality of tensions cables  44 , and a plurality of corner members  46 . Each top member  26 ,  28  can include a frame member  48 ,  50  and a track member  52 ,  54  that both extend the entire length of the respective top member  26 ,  28 . The top members  26 ,  28  can be formed by an extrusion process such that the track member  52 ,  54  is integrally formed as one piece with the frame member  48 ,  50 . 
     Due to the integral formation of the track member  52  with the frame member  48 , a common side wall  56 ,  58  (the common side wall  56  of the first panel is viewable in  FIGS. 3 and 4  and the common side wall  58  of the second panel  24  is viewable in  FIG. 2 ) can form a portion of each of the frame members  48 ,  50  and the track members  52 ,  54 . The common side walls  56 ,  58  can provide a continuous load path for the forces exerted on the track members  52 ,  54  by the hanger assemblies  18  to the respective frame members  48 ,  50 . This continuous load path can be a more efficient load distribution path than that provided by the two-piece track and top primary member assembly of  FIG. 1 . For example, the junction of the top primary member and the track member of  FIG. 1  can be discontinuous due to dimensional tolerances and variations in material flow when these components are formed that can permit gaps between the abutting surfaces of the top primary member and the track member where they are not joined by the stitch weld seam. Further, raw material savings can be achieved with the one-piece top member of  FIGS. 2-4  as compared to the two-piece configuration of  FIG. 1  because the flanges of the separate track member are not necessary, due to this improved load path of the one-piece top member  26 . 
     The continuous, one-piece extruded top member  26  can provide a further cost and time advantage as compared to the two-piece configuration illustrated in  FIG. 1 . In the two-piece design of  FIG. 1 , the top primary member and the track member can be formed in separate extrusion processes. Further, the top primary member and the track member are then joined together in a separate manufacturing process, such as, by a plurality of weld seams that can extend the entire length of these components. Typically, the top primary member and the track member of  FIG. 1  can be formed from aluminum and can require specialized welding skills to join these two components. Thus, assembly time and manufacturing and/or labor costs can be reduced by forming the frame member and the track member in a single manufacturing step as an integral, one-piece extrusion, as compared to the two-piece design of  FIG. 1 . 
     The cross member  38  can have a longitudinal axis that extends vertically through the center of the cross member  38 . As shown in the embodiment of  FIGS. 3 and 4 , the longitudinal axis will intersect with the wall  64  of the top member  26 . However, the longitudinal axis will be completely spaced from the track member, and particularly from that portion of the track member that will be in contact with the rollers of the trolley. 
     The details of the top members  26 ,  28  will now be discussed with reference to  FIG. 3 . The top members  26 ,  28  of the first and second panels  22 ,  24  can be identical in cross-section. As such, only the cross-section of the first panel top member  26  will be discussed. The first panel frame member  48  can be a hollow tube that has a rectangular cross-section defined by the common side wall  56 , a top wall  60 , a side wall  62 , and a bottom wall  64 . The common side wall  56 , the top wall  60 , the side wall  62 , and the bottom wall  64  are all extend continuously from and are homogenous with each other. 
     The track member  52  can include the common side wall  56 , an upper wall  66 , a side wall  68 , two horizontal flanges  70 ,  72 , an arcuate flange  74 , and an intermediate arcuate flange  76  that all extend the length of the top member  26  and can be formed as a continuous, homogenous component during the extrusion of the top member  26 . (The details and function of the arcuate flanges  74 ,  76  will be discussed below.) 
     The upper wall  66 , the side wall  68 , the common side wall  56 , and the two horizontal flanges  70 ,  72  can include inner surfaces  56   a,    66   a,    66   b,    66   c,    66   d,    66   e,    68   a,    70   a,    72   a  that define a guide passage  78 . The guide passage  78  can receive the hanger assemblies  18  and provides a guide track along which the trucks (not shown—see  FIG. 1 , for example) of the hanger assemblies can pass as the modular panel gate assembly  12  moves between the opened position and the closed position. Specifically, the vertical rollers (not shown—see  FIG. 1 , for example) can engage and roll along the inner surfaces  70   a,    72   a  of the two horizontal flanges and the two rail surfaces  66   b,    66   c  formed on the inner surface  66   a - e  of the upper wall  66 . The horizontal rollers (not shown—see  FIG. 1 , for example) can engage and roll along the respective inner surfaces  56   a,    68   a  of the common side wall  56  and the side wall  68 . 
     Also illustrated in  FIG. 3 , a space can be provided between the ends  70   b,    72   b  of the two horizontal flanges  70 ,  72  to define an opening  80  to the guide passage  78 . The opening  80  can provide access to the guide passage  78  for a portion of the truck of the hanger assemblies  18  as the modular panel gate assembly  12  moves between the closed position and the opened position. 
     The inner surface  66   a - e  of the track member upper wall  66  can include a recess  66   a  intermediate the two rail surfaces  66   b,    66   c.  The recess  66   a  can provide clearance for a portion of the truck to pass through the guide passage  78  as the modular panel gate assembly  12  moves between the closed position and the opened position. 
     With continued reference to  FIG. 3 , the bottom wall  64  of the frame member  48  can join the common side wall  56  at a position inward of the lower end  56   b  of the common side wall  56 . The inboard horizontal flange  70  can extend from the lower end  56   b  of the common side wall  56 . Thus, the bottom wall  64  of the top member  48  can be positioned intermediate the levels of the top wall  48  and the inboard horizontal flange  70 . 
     As illustrated by way of example in  FIGS. 3 and 4 , the first and second panels  22 ,  24  can be joined to each other by a splice pin  82 , a pair of splice assemblies  84 ,  86 , and a central fastener  88 . The splice pin  82  can cooperate with the arcuate flanges (see for example,  74 ,  76 ) of the first and second panel track members  52 ,  54  to maintain proper alignment of the track members  52 ,  54  as the modular panel gate assembly  12  passes along the hanger assemblies  18 . The splice assemblies  86  can provide a rigid connection between the first and second panels  22 ,  24  without damaging the top and bottom members  26 ,  28 ,  20 ,  32  when the modular panel gate assembly  12  is static and when the modular panel gate assembly  12  moves between the closed position and the opened position. The splice assemblies  86  can also provide and maintain proper alignment of the first and second panels  22 ,  24  when the modular panel gate assembly is static and when it moves between the closed position and the opened position. Moreover, the splice assemblies  86  can include a splice plate  94  that can bend to some degree within a first plane containing the panels  22 ,  24 . The bending of the splice plate  94  allows a certain degree of relative vertical movement between the panels  22 ,  24 . The splice plate  94  can be relatively stiff in planes normal to the first plane such that little or no bending of the splice plate  94  occurs in these directions. The central fastener  88  can pass through the exterior cross members  36 ,  38  to maintain contact between these two abutting cross members  36 ,  38 . 
     As stated above, the track member  52  can include an arcuate flange  74  and an intermediate flange  76 . These arcuate flanges  74 ,  76  can cooperate with the splice pin  82  to provide and maintain alignment of the first panel track member  52  with the second panel track member  54  as the hanger assemblies  18  transition between the track members  52 ,  54  of the first and second panels  22 ,  24 . 
     The arcuate flange  74  can extend continuously from and homogenously with the junction  90  of the side wall  68  and the outboard horizontal flange  72 . The intermediate arcuate flange  76  can extend from the outer surface  72   b  of the outboard horizontal flange  72  at a position intermediate the end  72   b  of the outboard horizontal flange  72  and the arcuate flange  74 . The arcuate flanges  74 ,  76  can curve towards one another and terminate at free ends  74   a,    76   a  that are spaced from one another. The inner surfaces of the arcuate flanges  74 ,  76  can cooperate with one another to define a cylindrical groove  92  that can extend along the entire length of the top member  26 . As viewed in  FIG. 3 , the free ends  74   a,    76   a  can be spaced apart by a distance less than the diameter of the cylindrical groove  92  to prevent the splice pin  82  from falling out of the cylindrical groove  92 . 
     Other configurations of the splice pin  82  and the groove  92  can be used, such as a pin and a groove having complimentary polygonal cross-sectional shapes. In addition, a typical roller pin can be used. The pin  82  can be hollow or solid, and can be non-symmetrical in cross-section and configured to mate with a non-symmetrical groove. 
     The cylindrical groove  92  and the splice pin  82  can be dimensioned and configured such that the splice pin  82  can be received in the cylindrical groove  92  by an interference fit. The splice pin  82  can be configured and dimensioned to provide a rigid joint between the track members  52 ,  54  of the first and second panels  22 ,  24  by cooperating with the arcuate flanges  74 ,  76  to at least minimize deflection of the outboard horizontal flange  72  of the first panel  22  relative to the outboard horizontal flange (not numbered) of the second panel  24  as the truck passes from the first panel track member  52  to the second panel track member  54 . Thus, the modular panel gate assembly  12  can experience an unimpeded and relatively smooth transition as the panel joint  26  traverses each hanger assembly  18 . 
     The splice assemblies  86  and the central fastener  88  can secure the second panel  24  to the first panel  22  such that the second panel  24  can rigidly extend from the first panel  22  in a cantilevered manner when the second panel  24  is positioned beyond the support post assemblies  14  in a static configuration (for example, when the modular panel gate assembly  12  closes more than half of the gate opening). The splice assemblies  86  and the central fastener  88  can also provide a rigid cantilevered connection between the first and second panels  22 ,  24  when the second panel  24  does not engage either of the support post assembles  14  while the modular panel gate assembly  12  moves between the closed position and the opened position. 
     Each splice assembly  86  can include a rectangular splice plate  94  and a plurality of fasteners  96 . Each splice plate  94  can include a first plurality of through holes  98  and a second plurality of through holes  100 . The first plurality of through holes  98  can be configured and dimensioned to align with a plurality of through holes (not illustrated) that can be provided in the first panel  22 . The second plurality of through holes  100  can be configured and dimensioned to align with a plurality of through holes that can be provided in the second panel  24 . 
     As illustrated in  FIG. 4 , through holes  102  can be provided in the top surface  30   a  of the first panel bottom member  30  at a position adjacent to and inboard of the second exterior cross member  38 . Similarly, through holes (not visible) can be provided in the bottom surface (not visible) of the first panel frame member  48  at a position adjacent to and inboard of the second exterior cross member  38 . The pattern and location of the through holes in the first panel frame member  48  can be identical to the pattern and location of the through holes  104  in the first panel bottom member  30 . 
     As with the first panel  22 , through holes  104  can be provided in the top surface  32   a  of the second panel bottom member  32  at a position adjacent to and inboard of the first exterior cross member  36 . Similarly, through holes (not visible) can be provided in the bottom surface (not visible) of the second panel frame member  50  at a position adjacent to and inboard of the first exterior cross member  36 . The pattern and location of the through holes in the second panel frame member  50  can be identical to the pattern and location of the through holes  104  in the second panel bottom member  32 . 
     The number of through holes in each of the frame members  48 ,  50  and the bottom members  30 ,  32  can total four and the number of through holes  98 ,  100  in each splice plates  94  can total eight. However, any number of through holes and fastener assemblies  96  can be used in order to rigidly secure the first panel  22  to the second panel  24  in a cantilevered configuration. 
     The fastener assemblies  96  can include a threaded fastener (such as a bolt), a lock washer, and a flat washer. The threaded fasteners  96  can be inserted into respective through holes of the panels  22 ,  24  and the splice plates  94  to secure the splice plates  94  to the first and second panels  22 ,  24 . 
     As shown in  FIGS. 3 and 4 , an upper splice plate  94  can be inserted into the hollow passage  106  of the first panel frame member  48  and secured to the inner surface of the bottom wall  64 . After aligning the first plurality of through holes  98  of the upper splice plate  94  with their corresponding plurality of through holes (not shown—see, for example, the through holes  102  of the bottom member  30  shown in  FIG. 4 ) in the bottom wall  64 , the threaded fasteners can be inserted through the aligned through holes and partially tightened so that alignment of the panels  22 ,  24  can occur. 
     Similarly, the lower splice plate  94  can be inserted into the hollow passage  108  of the first member bottom member  30  and secured to the inner surface of the top wall (not numbered) and loosely secured with a plurality of fastener assemblies  96 . 
     After the splice pin  82  and the splice plates  94  have been loosely secured to the first panel  22 , the second panel  24  can be joined to the first panel  22 . First, the second panel  24  can be aligned with the splice pin  82  and the splice plates  94 . Next, the second panel  24  can be displaced toward the first panel  22  so that the splice pin  82  enters the cylindrical groove (not visible) in the second panel track member  54  and the splice plates  94  enter the hollow passages (not visible) of the second panel top and bottom members  28 ,  32 . Next, the first and second panels  22 ,  24  can be adjusted in alignment so that the through holes  100  of the upper splice plate  94  align with the trough holes (not visible) in the second panel frame member  50  while a straight edge spans the panel joint  26 . Next, the threaded fasteners of the fastener assemblies  96  can be inserted into the through holes and all of the threaded fasteners can be fully tightened to secure the first and second panels  22 ,  24  to the upper splice plate  94 . These last two steps can be repeated for the lower splice plate  94  and the second panel bottom member  32 . Finally, the central fastener  88  can be inserted into a central through bore  110 ,  112  in each of the exterior cross members  36 ,  38  and tightened. The central fastener  88  can include a threaded fastener (such as a bolt), a washer and a threaded nut. 
     The customer can complete the final assembly on-site without the need for highly skilled labor. Thus, reducing overall costs and assembly time. 
     The panels can be joined by other structure/methods, such as clamps, rivets, differently shaped splice plates, splice tubes, bolts, etc. 
     After, the first and second panels have been secured together, the modular gate can be hung on the hanger assembly and the alignment of the first and second panels can be fine tuned by tightening respective cables to eliminate any sagging that may occur in the panels. 
     With reference to  FIG. 1 , the catcher assembly  16  can include a post  114 , a catcher,  116 , and a companion  118 . The companion  118  can be configured and dimensioned to mate with the catcher  116  when the modular panel gate assembly  12  is in the closed position. The companion  118  can be secured to the second external cross member  40  of the second panel  24 . Alternatively, catcher assembly  16  can be positioned on the other side of the modular panel gate assembly  12 , as viewed in  FIG. 1 , such that the companion  118  can be secured to the first external cross member  34  of the first panel  22  and the post  114  with the catcher  116  can be positioned so that the first external cross member  34  is spaced from the post  114  when the modular gate panel assembly  12  is in the opened position and the first cross external member is adjacent the post  114  when the modular gate panel assembly  12  is in the closed position. Thus, the catcher assembly  16  can be used with a left-hand opening modular gate panel assembly and a right-hand opening modular gate panel assembly  12 . 
     While certain embodiments of the invention are described above, it should be understood that the invention can be embodied and configured in many different ways without departing from the spirit and scope of the invention. For example, the top member can be produced by other known forming methods, for example, hydroforming, casting, folding sheet metal, etc. However, some forming methods may dictate or permit a completely different cross-sectional shape, and therefore it must be determined whether certain forming methods are appropriate for a particular application of the disclosed subject matter. Additionally, the top frame members (and other frame members and gate components) can be produced from other various materials such as aluminum, steel, steel alloys, aluminum alloys, plastics, resin materials, composite plastics, ceramic materials, etc. The extrusion process allows the entire top member to be formed of a single continuous and homogenous material. 
     With regard to the splice assembly  86 , other forms of the splice assembly are contemplated and should fall within the scope of the presently disclosed subject matter. For example, the splice plates could be vertically oriented instead of horizontally oriented as shown. In addition, the plates  94  could be sized and shaped in many different ways, and mate with other and differently shaped portions of the top and bottom members  22 ,  24 ,  30 ,  32 . 
     As indicated above, the frame member  48  can take on many different shapes and need not be a rectangular tube structure as shown in the drawings. For example, the frame member  48  could alternatively be formed as an open I-beam structure in either a horizontal or vertical orientation. The frame member  48  can also be configured to be non-symmetrical in cross-section, polygonal in cross-section, rounded in cross-section, tubular in cross-section, etc. Likewise, the track member  52  can be formed in many different shapes, sizes and orientations with respect to the frame member and fall within the scope of the presently disclosed subject matter. In addition, the trolley could be carried on exterior surfaces of the track member  52  as well as other and differently shaped interior surfaces of the track member  52 . It is even contemplated that the track member  52  and frame member  48  be incorporated into a bottom member of the device. 
     While the subject matter has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. All related art references discussed in the above Description of the Related Art section are hereby incorporated by reference in their entirety.