Abstract:
A screening device is provided with multiple channel upper and lower panel retaining members that allow multiple panel members to be slid in front of or behind each other. Channel end caps and close spacing of the upper and lower panel retaining members prevent removal of the panels from the screening device. A support structure uses angled castings and extrusion members for rapid custom screen device assembly that avoids long welding assembly times as well as subsequent weld failure due to screen device vibration. A corner panel, decorative trim, a top panel retaining member alignment tang, and a fastener concealing end cap are also provided.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. provisional application 60/376,476 filed on Apr. 30, 2002 all of which is incorporated here by reference as if completely written herein. 

   BACKGROUND OF INVENTION 
   1. Field 
   This invention relates to screening devices and related types of apparatus. It has to do primarily with apparatus for screening the view of large outdoor equipment where it is necessary or desirable to improve its appearance in public places. For example, the invention can provide attractive screening for heating, ventilating, and air conditioning equipment on top of business establishments in areas of a city where all outdoor structures are required to have a pleasing appearance. In particular this invention relates to an improved screen device in which sheets are slidably contained within upper and lower tracks and secured within the tracks by permanently attached end caps. 
   2. Background 
   As set forth in U.S. Pat. No. 5,664,384, screening apparatus for large equipment can be difficult and time consuming to remove when it is necessary to make repairs or adjustments unless the screening apparatus is constructed and arranged so that it can be moved easily from its normal location around the equipment. In that patent, the screening apparatus was designed so that panels could be moved quickly and easily away from, and back to, their normal screening location by a single person without need for equipment to move the screening apparatus. Unfortunately, it has been found that on occasion severe weather conditions would force the panels from their securing tracks. And even more perversely, it has been found that individuals repairing the screened equipment often removed the panels and then failed to replace them after the repairs had been completed. 
   In addition to the problem of “lost” panels, members of the framework supporting the panels and the channels in which they were mounted were typically welded together. This of course required extensive and exact setup prior to and during the welding process. Further, due to the vibration of the underlying equipment to which the screen was mounted, welds were found to be subject to breakage with subsequent deleterious consequences to the screen panels. 
   In order to overcome these problems, it is an object of the present invention to provide a framework that is easy to assemble. 
   It is another object of the present invention to provide a framework that is adjustable with only a minimum of assembler effort. 
   It is another object of the present invention to provide a framework that avoids weld breakage. 
   It is yet another object of the present invention to provide covering panels (sheets) that afford easy access to the underlying machinery. 
   It is another object of the present invention to provide covering panels that are incapable of being removed from their tracks. 
   It is another object of the present invention to provide covering panels capable of accepting user indicia. 
   It is therefore the main purpose of the present invention to provide quick and easy access to the screened unit while preventing loss of the screening sheets and providing an attractive appearance at all other times with an assembly that is easy to assemble and which avoids breakage due to severe machinery vibration. The foregoing and other objects, features and advantages of the invention will become apparent from the following disclosure in which one or more preferred embodiments of the invention are described in detail and illustrated in the accompanying drawings. It is contemplated that variations in procedures, structural features and arrangement of parts may appear to a person skilled in the art without departing from the scope of or sacrificing any of the advantages of the invention. 
   SUMMARY OF INVENTION 
   These and other objects are met by the present invention or a screening apparatus which comprises two or more panels with each panel having a pair of parallel opposite edges. These panels are held at a predetermined location by means of a holding framework that includes an upper, rigid, elongate and substantially channel shaped top panel retaining member that is held in an upper lengthwise horizontal position. This top panel retaining member has at least two, spaced-apart upper channels that face in a substantially downward direction. The holding framework also includes a lower rigid elongate substantially channel shaped bottom panel retaining member that is held in a lower lengthwise horizontal position. The bottom panel retaining member also has at least two, spaced-apart lower channels that are parallel to and face substantially upward toward the top panel retaining member. The top panel retaining member and the bottom panel retaining member being spaced sufficiently close to each other so as to prevent removal of the panels by moving the panels upward into the upper channels and swinging the lower edge of the panels out of and away from the lower channels. The upper channels formed in the top panel retaining member are spaced apart sufficiently from each other as are the lower channels to allow for unobstructed passage of said panels with respect to each other when the panels are slidably moved, i.e., laterally moved, in the upper and lower channels with respect to each other. That is, the channels provide for sufficient spacing between the panels so that they can be moved past each other in their respective upper and lower channels. End caps are positioned over the ends of either the lower channels or the upper channels or both to prevent the panels from being removed from the upper and lower channels by lateral movement of said panels in the channels. That is, the end caps prevent the removal of the panels by laterally sliding them along and out of the ends of the channels. The use of panels that are laterally slidable under and over each other allows quick and easy access to the underlying machinery that the panels screen while at the same time preventing their inadvertent or malicious removal from the screening device. 
   The present invention also features a corner supporting structure that is comprised of a vertical corner member that is typically attached to the device to be screened and two lower horizontal members, each with first and second ends, with the horizontal members attached to the vertical corner member at right angles to each other at their first ends. Two vertical angular support members with first and second ends are attached at their lower first ends to the second (distal) ends of the lower horizontal members and at their upper ends to an upper portion of the vertical corner member. 
   A horizontal corner member is attached at its ends to the second distal ends of the two horizontal members. 
   The present invention features angular castings that are used to attach the various members of the corner supporting structure to each other. Thus first angled castings are used to attach the ends of a corner horizontal member to the second (outer) ends of the horizontal members that are mounted at right angles to each other. The upper ends of the vertical angular support members are attached to the vertical corner member with second angular castings while the lower ends of the vertical angular support members are attached to the second (distal) end region of the horizontal members with third angular castings. The use of standard extrusions for the horizontal, horizontal corner, and vertical angular support members along with angular castings has the advantage of allowing for a wide variety of custom configuration screening devices. In addition, the use of mechanical fasteners to attach the various extrusion members and castings to each other and to the vertical corner member has the advantage requiring only simple tools for the assembly of the screening device and avoids time consuming setup and clamping operations required when the various corner components are welded to each other. Moreover, the use of mechanical fasteners eliminates welded joint failure caused by screened device vibration. 
   By attaching the top panel retaining member to the upper portion of the vertical corner member and the bottom panel retaining member to the distal ends of the lower horizontal members, a canted orientation of the panels is produced. That is, the panels are slanted from vertical and slope away from the base of the structure to be screened. 
   A vertical panel orientation can be achieved by adding two upper horizontal members that are attached to the vertical corner member at right angles to each other. When the top panel retainer member is mounted to the ends of these upper horizontal members and the bottom panel retainer member is mounted to the ends of the lower horizontal members, a vertical panel orientation is achieved. When both upper and lower horizontal members are used, a second vertical member is placed between the outer ends of the upper and lower horizontal members to provide additional structural rigidity. 
   The present invention also features an alignment tang that projects from the top panel retaining member and engages the top end of the vertical corner member. The alignment tang has the advantage of allowing rapid positioning of the top panel retaining member and serves as a “second hand” while the top panel retaining member is fastened to the vertical corner member. 
   The present invention also features an elongate trim member that can be fastened directly to the top panel retaining member or by means of an attachment bracket. The attachment bracket has the advantage of allowing the trim member to extend further outward from the top panel retaining member thereby affording a longer downward extent to better conceal the top panel retaining member when a canted panel assembly is used. 
   A corner panel (sheet) is used to cover the corner supporting structure and is typically attached to the vertical angular support members by bending the edges of the corner panel to align with the edge surface of the vertical angular support members. The bottom edge of the corner panel can also be bent to align with the edge surface of the horizontal corner member and attached to the corner member with fasteners such as screws. 
   The end cap can be formed to cover the ends of both the upper and lower channels. By bending the end cap at right angles to the end surface (parallel to the top and bottom panel retainer members) and then again at a right angle away from the panel retainer members, the end cap can be fastened to the side of the vertical angular support member. The appropriate panel is slid out of the way while the end cap is fastened to the support member. On returning the panel to its closed position, the fastening screens are hidden from view. In addition, such an end cap arrangement has the advantage of concealing the fasteners used to attach the corner panel to the vertical angular support members. 
   The foregoing and other objects, features and advantages of the invention will become apparent from the following disclosure in which one or more preferred embodiments of the invention are described in detail and illustrated in the accompanying drawings. It is contemplated that variations in procedures, structural features and arrangement of parts may appear to a person skilled in the art without departing from the scope of or sacrificing any of the advantages of the invention. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is an exploded perspective view of the screening device of the present invention illustrating the major components of the system as used with a device such as an air conditioning unit including the upper and lower elongate members (upper and lower panel retaining members), rectangular sheets (panels), corner sheet (panel), and supporting frame structure. 
       FIG. 2  is an end view of the bottom panel retainer mounted to a horizontal extrusion member. 
       FIG. 3  is an end view of the top panel retainer mounted to a vertical corner member along with an upper trim member. 
       FIG. 4  is a top cross-sectional view along line  4 — 4  of  FIG. 1  illustrating the positioning of end caps at the ends of the bottom panel retainers and the attachment of the end caps to the angular vertical support member so as to conceal the fasteners used to secure the end caps and the corner sheet to the vertical angular support members. 
       FIG. 5  is a schematic perspective view of the corner framing structure illustrating the location of the angular castings (indicated by numbered circles) used to fasten the various framing members into a corner framing structure. 
       FIG. 6  is an end view of a framing extrusion used in the manufacture of the various frame support members. 
       FIG. 7  is a detailed partial top view of the circled portion  7  of  FIG. 5  illustrating the fastening assembly used to attach the ends of the horizontal extrusion members to the vertical corner member. 
       FIG. 8  is a detailed partial top view of the circled portion  8  of  FIG. 5  illustrating the attachment of the angled horizontal corner extrusion member to the horizontal extrusion member using a first angular casting. 
       FIG. 9  is a detailed partial plan view of the circled portion  9  of  FIG. 5  illustrating the attachment of the angular support extrusion member to the horizontal extrusion member using a second angular casting. 
       FIG. 10  is a partial plan view of the framing extrusion illustrated in  FIG. 5  and used in the manufacture of the various frame support members. 
       FIG. 11  is a detailed partial plan view of the circled portion  11  of  FIG. 5  illustrating the attachment of the vertical angular support extrusion member to the vertical corner member using a third angular casting. 
       FIG. 12  is a partial perspective drawing of a second embodiment of the invention illustrating the use of vertical upper and lower panel retention members with the upper retention member being supported by additional upper horizontal extrusion members in the supporting structure. 
       FIG. 13  is an end view of an alternate embodiment of an upper, double-step, elongate trim member attached to the top panel retainer using attachment brackets. 
   

   In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology is resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
   Although a preferred embodiment of the invention has been herein described, it is understood that various changes and modifications in the illustrated and described structure can be affected without departure from the basic principles that underlie the invention. Changes and modifications of this type are therefore deemed to be circumscribed by the spirit and scope of the invention except as the same may be necessarily modified by the appended claims or reasonable equivalents thereof. 
   DETAILED DESCRIPTION 
   As shown initially if  FIG. 1 , the present invention is a screening device generally designated by the numeral  10  that is used to improve the appearance of large outdoor equipment  6  such as heating, ventilating, and air conditioning equipment. In its basic form, the invention comprises a top elongate panel retaining member  20 , a bottom panel retaining member  30 , sheets  40  with parallel opposite edges, and end caps  50  (shown in  FIG. 4 ) that prevent the sheets  40  from being removed from the panel retaining members  20  and  30 . 
   As shown in  FIG. 1  and in further detail in  FIG. 2 , the bottom panel retainer  30  is comprised of two, spaced-apart, upward directed, U-shaped channels  32  and  34  which receive the lower edges of panels  40 . The U-shaped channels  32 ,  34  are spaced apart sufficiently so that panels  40 , which are typically ribbed for structural strength, may slidably move past each other when the lower edge of separate panels  40  are placed in channels  32 ,  34 . Typically and as shown in  FIG. 2 , the bottom panel retaining member  30  is an extruded member formed with an angled base  39  and orthogonal upward projecting fingers  31 ,  33 ,  35 , and  37 . Finger sets  31 ,  33  and  35 ,  37  along with a portion of angled base  39  form U-shaped channels  32  and  34 . Base  39  is attached to finger  33  which is an upwardly angled portion of horizontal C-section member  29 . Although not essential and other configurations are possible, a rib  23  is used to provide structural rigidity and to support the base  39  of the U-shaped channels  32 ,  34 . The C-section portion of extrusion  30  is formed from contiguous orthogonal members  25 ,  27 , and  29  and is sized to engage the end of horizontal member  82 . After engagement of the C-section portion of bottom panel retainer  30  to horizontal member  82 , it is secured to horizontal member  82  by means of suitable fastener such a machine screws, tapping screws or nuts and bolts. For example, a nut and bolt assembly  38  may be used in a vertical hole formed in C-section portions  25 ,  29  and the end of horizontal member  82 . Typically both end portions of bottom retaining member  30  are engaged to the ends of horizontal members  82 . However, when the length of the bottom retaining member is particularly long, additional horizontal members  82  may be used along the length of bottom panel retainer  30 . Although screw-type fasteners are typically used to secure the bottom retainer panel  30 , a quick release, clevis-type pin may also be used to secure panel retainer  30  to horizontal members  82 . Such quick-release pins enable the quick and easy removal of the bottom panel retainer  30 , when unencumbered access to the underlying machinery  6  is frequently required. 
   As noted, separate panels  40  are mounted in the two U-shaped channels  32  and  34  to allow the panels to slide past each other in channels  32 ,  34 . For ribbed panels  40 , the spacing between channels  32  and  34  is considerable to allow for unobstructed passage of the panels  40  behind or in front of each other. As such, separate fingers  31  and  35  have considerable separation between them. However, it is to be realized that fingers  31  and  35  may be formed as a single central finger when the clearance separation between panels  40  is sufficiently small. 
   Similarly and as shown in  FIGS. 1 and 3 , the top panel retainer  20  is also formed with two, spaced-apart, downward directed, U-shaped channels  22  and  24  which receive the upper edges of panels  40 . As with the bottom panel retainer  30 , the upper U-shaped channels are spaced apart sufficiently to allow panels  40  mounted in channels  22  and  24  to slide past each other. Preferably the top panel retainer  20  is an extrusion formed from a horizontal top section  48  and a vertical section  49  orthogonally joined at their ends. An angled top member  47  is joined to the opposite end of top section  48  and to the vertical section  49 . Fingers  42 ,  43 ,  44 , and  45  project downward orthogonally from top member  47  to form channels  22  and  24  that receive the upper edges of panels  40 . Channels  22  and  24  are spaced sufficiently far apart so as to allow panels  40  to pass in front of or behind each other. Fingers  43  and  44  may be formed as a single finger. An optional tang  51  projects outward from vertical section  49  and then orthogonally downward. The channel formed between tang  51  and vertical section  49  received the upper edge of corner member  64  and allows for rapid positioning of the top panel retainer with respect to corner member  64 . The top panel retainer  20  is attached at each end to corner member  64  with a suitable fastener such as a nut and bolt assembly  52  ( FIG. 3 ). When top panel retainer  20  is particularly long, additional pieces of flat members may be used along the length of retainer  20  (not shown). 
   The bottom panel retainer  30  and the upper panel retainer  20  are spaced apart from each other so as to securely hold the panels  40  in place. That is, panels  40  cannot be removed from the U-shaped channels  22 ,  24 ,  32 ,  34  by moving the panels upward in channels  22  or  24  and swinging the lower edge of panel  40  from channel  32  or  34 . In effect the spacing between the bottom panel retainer  30  and the upper panel retainer  20  is such that panels  40  can only be loaded and removed from the open ends of channels  22 ,  24 ,  32 , and  34 . 
   When end caps  50  are secured to both ends of bottom panel retainer  30  and upper panel retainer  20 , panels  40  are securely retained within the channels  22 ,  24 ,  32 , and  34  and are incapable of being removed from the channels. Although end cap  50  is typically formed as a single piece that covers the ends of bottom panel retainer  30  and upper panel retainer  20 , it is to be realized that end cap  50  can be comprised of two or more members that block the ends of channels  22 ,  24 ,  32 , and  34  and retain panels  40  within these channels. End caps  50 , shown in  FIG. 4  in cross section, extend along and are fastened to vertical angular support members  86  to close the channel ends of both the upper retainer  20  and lower panel retainer  30 . Although only shown with regard to the channel ends of channels  32 ,  34  of lower panel retainer  30 , it is to be realized that the upper portion of single end cap piece  50  also closes the ends of the channels  22 ,  24  of the upper panel retainer  20 . 
   With reference to  FIGS. 4 ,  5  and  7 , and initially  FIG. 7 , the ends of two horizontal members  82  are attached to vertical corner member  64  using a suitable faster such as a bolt or metal screw  83 . The ends of bottom retainer channel  30  are attached to the opposite second ends of horizontal members  82  by means of suitable fasteners such as the nut and bolt assembly  38  illustrated in  FIG. 2 . As further illustrated in  FIGS. 4 ,  5 , and  8 , a horizontal corner member  84  is also attached near the second ends of horizontal members  82  by means of angular castings  92 . The lower ends of vertical support members  86  are also attached near the second ends of horizontal members  82  and at their top to the upper portion of vertical corner member  64  as shown in  FIG. 1 .  FIGS. 5 and 11  illustrate the use of second angular castings  94  to attach the vertical angular support members  86  to the vertical corner member  64  while  FIGS. 5 and 9  further illustrate the use of third angular casting  96  to attach the lower ends of vertical angular support member  86  to horizontal extrusion member  82 . 
   Referring to  FIG. 4 , the vertical edges of corner sheet  46  are bent at an angle for attachment to vertical angular support members  86  by means of fasteners such as metal screws  62 . Similarly the base edge of corner sheet  46  is bent for attachment to horizontal corner member  84  with screws  62 . After the corner sheet  46  has been secured to the vertical and corner support members  82 ,  84 , the corner cap  50  is placed over the ends of the top and bottom panel retainers  20  and  30 . Only the capping of the channels  32 ,  34  of bottom panel retainer  30  is illustrated in  FIG. 4 , it being realized that a single end cap  50  extends upward along vertical angular support member  86  to also cap the channels  22 ,  24  of top panel retainer  20 . As shown in  FIG. 4 , end cap  50  is bent at right angles around two sides of vertical support member  86  and is attached to vertical support member  86  on the inside of the vertical support member  86 , it being realized that one of the rectangular sheets  40  is slid out of the way in upper and lower channel pairs  24 ,  34  or  22 ,  32  during the attaching process. Such an end capping means has the advantage of concealing all fasteners from view and lessens the possibility of unwanted removal. 
   As shown especially in  FIGS. 1–3 , the upper and lower panel retainers  20  and  30  are formed in such a fashion as to position the panels  40  at an angle to vertical, that is, the panels  40  slope downward away from the device being covered, i.e., a canted configuration.  FIG. 12  is a partial perspective view illustrating upper and lower panel retainers  20 ′ and  30 ′ that allow for vertical mounting of panels  40 . As illustrated, spaced-apart U-shaped channels  22 ′,  24 ′,  32 ′ and  34 ′ are open so as to provide a vertical panel orientation. 
   As seen in  FIGS. 1 and 4 , the top and bottom panel retainers  20  and  30 , panels  40 , corner panels  46 , and end caps  50  ( FIG. 4 ), are supported by means of a supporting structure  60  ( FIG. 5 ) comprised of vertical corner member  64 , horizontal extrusion members  82 , horizontal corner extrusion member  84 , and vertical angular support extrusion members  86 . A typical extrusion member  200  is shown in  FIGS. 6 and 10  and comprises a central tube in which is formed center bore  206 . Exterior corner arms  204  form a partially covered groove  202  on each side of the square-shaped extrusion  200 . Angular castings  92 ,  94 , and  96  are shown in  FIGS. 4 ,  5 ,  8 ,  9 , and  11  and are used to join extrusion members  82 ,  84 , and  86  to each other and to vertical corner member  64 . 
   Referring to  FIG. 7  (a top cross-section view of corner assembly  7  in  FIG. 5 ), two horizontal extrusions  82  are attached at right angles to each other by attaching their ends to vertical corner member  64 . The horizontal extrusions  82  are attached by screws  83  that pass through the orthogonal portions of corner member  64  into the center cylindrical bore  206  ( FIG. 6 ) of the horizontal extrusion  82 . 
   As shown in  FIG. 9 , a vertical angular support extrusion member  86  is attached at one end to horizontal extrusion member  82  by means of angular casting  96 . One end of angular casting  96  is attached to the angular support extrusion member  86  by means of a screw  97  driven into the bore  200  ( FIG. 6 ) of extrusion  86 . The other end of angular casting  96  is attached to horizontal extrusion member  82  by means of a nut and bolt assembly  98  passing through a hole drilled into horizontal extrusion member  82 . As shown in  FIG. 11 , the opposite end of angular extrusion  86  is attached to the vertical corner member  64  by means of second angular casting  94 . One end of casting  94  is attached to the vertical corner member  64  by means of nut and bolt assembly  66  while the other end of casting  94  is secured to the upper end of vertical angular extrusion  86  by means of a screw  87  that passes through a hole in casting  94  and then is screwed into the bore  200  ( FIG. 6 ) of angular extrusion  86 . 
   As shown in  FIG. 8 , the horizontal corner extrusion member  84  is fastened to the horizontal extrusion member  82  by means of first angular casting  92 . One end of angular casting  92  is attached to horizontal extrusion member  82  by means of nut and bolt assembly  74  while the other end of casting  92  is attached to corner extrusion member  84  by means of a screw  76  passing through a hole in the end of casting  92  and screwed into the bore  200  ( FIG. 6 ) of extrusion member  84 . The opposite end of extrusion member  84  is similarly attached to a second horizontal member  82  using a second corner casting  92  ( FIG. 5 ). 
   Referring to  FIGS. 1 and 4 , the vertical corner member  64  is attached to the screened device  6  by means of screws or other suitable securing means. Preferably the vertical corner member  64  extends slightly above the screened device  6  to enable easy attachment of top panel retainer  20  ( FIG. 3 ) by means of nut and bolt assembly  52 . An engagement tang  51  allows for quick alignment and positioning of retainer  20  during the attaching process. As seen in  FIG. 2 , the bottom panel retainer  30  is attached to the horizontal extrusion members  82  by means of a C-shaped channel formed by retainer  20  members  25 ,  27 , and  29  that accepts the end of horizontal extrusion member  82  and is secured to the extrusion member  82  by means of nut and bolt assembly  38 . Alternatively and as shown in U.S. Pat. No. 5,664,384, all of which is incorporated herein as if completely written herein, the screening device  10  may be attached to free standing posts or other alternative anchoring devices. 
   To complete the screening device  10 , a corner panel  46  ( FIGS. 1 and 4 ) is attached to vertical angular corner support extrusion members  86  and horizontal corner extrusion  84 , typically with suitable fasteners such as screws  62 . The corner panel  46  is attached under a side wall of end caps  50  ( FIG. 4 ) to allow removal and replacement of the end caps  50  in the event one or more of the panels  40  require replacement. Although panels  40  are typically made of plastic or light weight metal such as aluminum, fabric may be used, especially fabric onto which aesthetically pleasing senses of company logos and other indicia may be imprinted. 
   The screening device  10  is typically completed by attaching an upper trim panel  56  ( FIG. 3 ) directly to the top panel retainer  20 . Alternatively and as shown in  FIG. 13 , a double-step, upper trim panel  58  may be mounted outward from the top panel retainer  20  by means of attaching members such as attachment brackets  59  which are mounted to the top of retainer  20  with suitable fasteners such as sheet metal screws  57 . 
     FIG. 12  illustrates an alternative embodiment  110  of the present invention in which the top panel retainer  20 ′ and the bottom panel retainer  30 ′ are formed with spaced-apart U-channels  22 ′,  24 ′,  32 ′, and  34 ′ that have a vertical orientation to afford vertically aligned panels rather than the canted alignment of embodiment  10 . The supporting structure  160  is identical to that used with the canted orientation except that it further comprises two upper horizontal extruded members  182  fastened at right angles to each other with one end attached to the vertical corner member  64  in a fashion similar to the attachment of the lower horizontal members  82  as shown in  FIG. 7 . Vertical extrusion members  184  are attached directly to the upper horizontal extrusion members  182  and the lower horizontal extrusion members  82  by means of a screw passing through a hole formed and passing through extrusion members  182  and  82  and through which a screw is threaded into the center bore  200  ( FIG. 5 ) of the vertical extrusion member  184 . The top panel retainer  20 ′ and the lower panel retainer  30 ′ are attached to the ends of the horizontal extrusion members  82  and  182  by means of C-section channels  126  and  136  into which the ends of the horizontal extrusion members  82  and  182  are inserted and secured with suitable fastening devices. 
   It is possible that changes in configurations to other than those shown could be used but that which is shown is preferred and typical. Without departing from the spirit of this invention, various means of fastening the components together may be used. It is therefore understood that although the present invention has been specifically disclosed with the preferred embodiment and examples, modifications to the design concerning sizing, shape, attachment, and structural reinforcement will be apparent to those skilled in the art and such modifications and variations are considered to be equivalent to and within the scope of the disclosed invention and the appended claims.