Abstract:
An electronic sign having vertically hinged face panel doors which open individually about offset hinge assemblies and which aid in minimizing distorted seal compression. Individual door stop assemblies allow an operator to manageably open the face panel doors and to lock the face panel doors. In the open position, the face panel doors are protected from damage due to wind currents or gusts. The use of face panel doors having a parallelogram cross section profile allows for closely spaced face panel doors with a minimum panel-to-panel gap for uniform spacing and viewing of lighted pixel displays.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This patent application is related to patent application Ser. No. 11/227,599 filed Sep. 15, 2005, entitled “Electronic Display Panel,” which is pending and which is a continuation-in-part of patent application Ser. No. 11/148,461 filed Jun. 9, 2005, entitled “Sign System,” which is pending. 
     This patent application is also related to patent application Ser. No. 11/809,107 filed May 31, 2007, entitled “Electronic Sign Having A Formed Metal Cabinet,” which is pending. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is for an electronic sign, and more specifically, is for an electronic sign having vertically face panel doors. 
     2. Description of the Prior Art 
     Most existing prior art front access full matrix signage used large single panel top hinged lift face panels that were ungainly and awkward to open and close, difficult to seal against the elements, insects and the like, as well as involving an inordinate amount of time to gain access thereinto. Another concern is for the safety of technicians where support of a horizontally attached large heavy panel over the area where technicians are working on the display can be in danger if the support structural integrity is compromised. Other prior art devices used displays with multiple vertically hinged doors, but the pixels spacing at the vertical seams between doors was excessive due to large gaps between panels that allowed the doors to pivot open without incurring mutual door interference at adjacent door edges. Weather sealing provided by this design was very poor as the weather seals were small and thin in order to promote close juxtaposition of pixels from door-to-door. 
     Other prior art devices used horizontal panels that only allowed for partial (line) LED matrix to be displayed. Because of the space required for hinges and brackets between the panels, full matrix displays larger then a few feet tall were not possible. 
     Other prior art devices utilized a panel the size of the whole display face that was horizontally hinged across the top which, because of shear size, was difficult to properly weather seal. The large size of panel also required the use of gas shocks and/or several technicians to aid in lifting the panel out of place for access. Such a device also typically used a large piece of polycarbonate sheet across the entire face of the viewing area. In the present invention, the large piece of polycarbonate sheet is replaced by smaller pieces behind the multiple viewing hole face sheet but in front of the LED (light emitting diode) modules in each of the manageable multiple vertically hinged face panel doors. If a face panel is damaged by a projectile or in some other manner, it can be easier and more cost effective to repair a smaller face panel component compared to repair or placement of a much larger face panel. 
     Other signage using vertical hinges included large gaps in the LED matrix due to the interceding projecting structure of the hinge hardware. These gaps forced the pixel pitch to increase noticeably between face panels on all but the largest pixel pitches. These gaps were used so that the adjacent face panels could open and close without interference. The present invention overcomes such a problem by the suitable placement of the hinge pivot axis and by the use of face panel doors having parallelogram cross sections in order that a very minimal gap can be used. 
     The present invention allows for a quick, easy and safe way to access the sign, to seal the sign, and to provide for continuous viewing of LED pixels made possible by minimum sized gaps between adjacent LED display matrixes. 
     SUMMARY OF THE INVENTION 
     The general purpose of the present invention is to provide an electronic sign having vertically hinged face panel doors. 
     The invention is an electronic sign having vertically hinged face panel doors which allow for easy access to the inside of the sign from the front by the opening of one or more manageable vertically hinged face panel doors instead of one large and heavy face panel. Structure is provided to allow for a full matrix display where the face panel seams do not prevent the pixel spacing from being uniform across the broad matrix of the sign. 
     Another important aspect of the face panel door design is the parallelogram shape of the cross section as viewed from above. The horizontally aligned parallelogram shaped top panel (and bottom panel) of the face panel doors are in an angled relationship with respect to the vertically aligned and opposed side panels of the configured face panel doors. Such angled alignment provides ability for the face panel doors to open and close without any physical interference with neighboring face panel doors and, when closed, to form a very small gap between the face panels of adjacent face panel doors. Any face panel door can be opened and closed independently and without difficulty regardless of whether neighboring face panel doors are open or closed. 
     The face panel doors have upper and lower hinge bracket assemblies that place the vertically aligned pivot axis slightly forward of the face panel door and to the one side of the face panel door. The hinge bracket assemblies are placed so that the face panel doors can pivot without interference with each other. The position of the hinge pivot axis is also important in that it allows the foam weather seal to be compressed at as close to an optimal angle as possible. Ideally, a flexible weather seal should be compressed as close to straight on as possible. This is achieved by making the angle between the plane of the seal and the plane of the hinge bracket assemblies as close to zero as possible. The pivot point assemblies are placed as close to the face sheet and as far as possible to one side while still allowing the panels to operate without physical interference. 
     Door stop assemblies are another very important feature of the present invention. When the face panel doors open to 90 degrees they are automatically and securely held in position by a gravity activated door stop assembly consisting of opposed mirror image-like slotted track channels at the top and bottom of the frame slidingly connected to and linked to the face panel door by opposed horizontally oriented cross bar links. A handle in the form of a vertically aligned link bar attaches to both cross bar links wherein the components can operatively function as a single system. The linkage bar handle enables an individual to operate the door stop assembly components connected to an individual face panel door from any associated location within a partially open position. The door stop assemblies hold the face panel doors securely so that the face panel doors&#39; other components of the invention sign can be serviced safely, even under windy conditions, thereby preventing inadvertent rotation of the face panel doors and thus preventing injury to service personnel. 
     According to one or more illustrations of the present invention, there is provided an electronic sign having a frame, a plurality of vertically hinged face panel doors secured to the frame, a plurality of offset hinge assemblies securing the hinged face panel doors to the frame, a door stop assembly attached between the plurality of face panel doors and the frame, robust captivated bolt door latches secured to the upper and lower forward regions of the face panel doors and door catches secured to the upper and lower forward regions of the frame. Also included in the face panel doors are vertically aligned spacers, LED display modules and a protective polycarbonate sheet. 
     One significant aspect and feature of the present invention is the use of vertically hinged face panel doors allowing front access while still maintaining a full matrix LED display without visual interference by hinges. 
     Another significant aspect and feature of the present invention is a structure which allows a single person to safely open the face panel door or doors without mechanical assistance. 
     Still another significant aspect and feature of the present invention is that the electronic sign is more easily serviced because the face panel doors are lightweight individual structures which can be easily manipulated by one person. 
     Still another significant aspect and feature of the present invention is the ability to display full, line, and partial matrix displays. 
     Yet another significant aspect and feature of the present invention is that there are no noticeable gaps in the pixel distribution. 
     Yet another significant aspect and feature of the present invention is the parallelogram profile of the access door when viewed from the top. 
     Yet another significant aspect and feature of the present invention is the ability to handle increased wind loads because the doors can be built with a deep enough depth to add extra support members. 
     Still another significant aspect and feature of the present invention is the use of individual polycarbonate sheets placed between the face panel and the LED display modules in order that smaller door sections can be used in the display. 
     Yet another significant aspect and feature of the present invention is the use of top and bottom latches in each door having rugged captivated bolt latches for durability. 
     Still another significant aspect and feature of the present invention is the use of door stops which keep the wind from moving a face panel door when it is open. 
     Yet another significant aspect and feature of the present invention is the placement of the door hinges that provide the proper motion of the face panel doors so that the weather seal becomes properly sealed. 
     Having thus briefly described embodiments of the present invention and having mentioned some significant aspects and features of the present invention, it is the principal object of the present invention to provide an electronic sign having vertically hinged face panel doors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
         FIG. 1  is an isometric view of an electronic sign having vertically hinged face panel doors, the present invention; 
         FIG. 2  is a semi-exploded isometric view of the components of  FIGS. 1 ,  3  and  4 ; 
         FIG. 3  is an isometric view of an electronic sign having vertically hinged face panel doors; 
         FIG. 4  is another isometric view of an electronic sign having vertically hinged face panel doors; 
         FIG. 5  is a vertical cross section view through the frame along line  5 - 5  of  FIG. 2 ; 
         FIG. 6  is an exploded view of a face panel door; 
         FIGS. 7 and 8  are segmented isometric views showing the attachment of a top hinge bracket assembly to a top panel of the face panel door and of the attachment of a bottom hinge bracket assembly to the bottom panel of the face panel door; 
         FIG. 9  is a segmented isometric view showing the top latch assembly secured to the front of the face panel adjacent to the top panel of the face panel door and, correspondingly, of the bottom latch assembly secured to the front of the face panel adjacent to the bottom panel of the face panel door; 
         FIG. 10  is an exploded view of the structure of a top latch assembly; 
         FIG. 11  is a foreshortened isometric view of the door stop assembly used to lock the face panel doors in the open position; 
         FIG. 12  illustrates the door stop assembly in use to hold a face panel door in the open position; 
         FIG. 13  is a top view of several face panel doors or portions thereof secured to a frame; and, 
         FIGS. 14   a  and  14   b  illustrate the operation of the door stop assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 ,  3  and  4  are isometric views of an electronic sign  10  having vertically hinged face panel doors  36   a - 36   n .  FIG. 2  is a semi-exploded isometric view of the components of  FIGS. 1 ,  3  and  4 .  FIG. 5  is a vertical cross section view through the frame  12  shown in  FIGS. 1 ,  2 ,  3  and  4  through line  5 - 5  of  FIG. 2 . With reference to  FIGS. 3 ,  4  and  5 , and especially to  FIGS. 1 and 2 , fully or partially illustrated components of the invention are now described. The frame  12 , to which multiple components are aligned and secured, includes configured channels including a top channel  12   a , opposed end channels  12   b  and  12   c , and a bottom channel  12   d . A continuous lip  13  is formed by vertically aligned portions of the top channel  12   a , opposed end channels  12   b  and  12   c , and the bottom channel  12   d . A plurality of vertically aligned formed channels  14   a - 14   n , referenced in pending patent application Ser. No. 11/809,107 entitled “Electronic Sign Having a Formed Metal Cabinet” filed May 31, 2007, extend and are secured between the top channel  12   a  and the bottom channel  12   d  to provide for support between the top channel  12   a  and the bottom channel  12   d  and to serve partially as a mounting structure for a back panel  15 . The back panel  15 , which accommodates electronic circuitry and which has multiple vents  16 , is secured to the rear perimeter of the frame  12 . A plurality of vertically aligned bottom supports  17   a - 17   n  is secured to the bottom of the bottom channel  12   d . Lifting lugs  18  are secured to the frame  12 . Mounting brackets  20  and  22  are aligned over the back panel  15  and are secured to the perimeter of the frame  12 . 
     A plurality of lower and upper lipped panels  24   a - 24   n  and  26   a - 26   n , respectively, is aligned between the ends of lipped panels  28  and  30  and are combined to form a facia panel  32 . The inwardly extending interior lips of each lower and upper lipped panels  24   a - 24   n  and  26   a - 26   n  and of the end lipped panels  28  and  30  are aligned and are secured to the inner perimeter of the frame  12 ; i.e., to the top channel  12   a , opposed end channels  12   b  and  12   c , and the bottom channel  12   d , respectively. The outwardly located vertically aligned main panel portions of the lower and upper lipped panels  24   a - 24   n  and  26   a - 26   n , respectively, and of the end lipped panels  28  and  30  are aligned and are secured to the continuous lip  13  located at the forward perimeter of the frame  12 . A plurality of supports  34   a - 34   n  is distributed and secured to the end channels  12   b  and  12   c  of the frame  12  in order to provide additional support for the end lipped panels  28  and  30  of the facia panel  32 . Thus, the facia panel  32  is secured to the frame  12 . 
     The upper portion of a plurality of similarly constructed face panel doors  36   a - 36   n  are hinged and rotatingly secured to the top channel  12   a  of the frame  12  by the use of a plurality of top hinge bracket assemblies  38   a - 38   n  and the lower portion of the plurality of face panel doors  36   a - 36   n  are hinged and rotatingly secured to the bottom channel  12   d  of the frame  12  by the use of a plurality of bottom hinge bracket assemblies  40   a - 40   n . A plurality of robust and rugged top latch assemblies  42   a - 42   n  is distanced from the top hinge bracket assemblies  38   a - 38   n  along the plurality of face panel doors  36   a - 36   n  and suitably secured to the upper front of the face panel doors  36   a - 36   n . A plurality of bottom latch assemblies  44   a - 44   n  is distanced from the bottom hinge bracket assemblies  40   a - 40   n  along the plurality of face panel doors  36   a - 36   n  and suitably secured to the lower front of the face panel doors  36   a - 36   n . When the face panel doors  36   a - 36   n  are in the closed position, the top latch assemblies  42   a - 42   n  and the bottom latch assemblies  44   a - 44   n  are aligned with a plurality of top catch assemblies  46   a - 46   n  and a plurality of bottom catch assemblies  48   a - 48   n  located in the top channel  12   a  and the bottom channel  12   d , respectively, in order that mutual engagement therewith can be effected. A plurality of ramped guides  50   a - 50   n  is located on an upper surface of the bottom channel  12   d  to ensure suitable vertical clearance of the bottom of the face panel doors  36   a - 36   n , respectively. A plurality of door stop assemblies, such as door stop assembly  52 , as described later in detail, is included between each of the face panel doors  36   a - 36   n  and the bottom and top channels  12   d  and  12   a , such as shown by the door stop assembly  52  at the hinged side of the face panel door  36   a  in  FIG. 2 . 
       FIG. 5  is a vertical cross section view through the frame  12  along line  5 - 5  of  FIG. 2  showing the alignment of the formed channel  14   a  between the top channel  12   a  and the bottom channel  12   d . For the purpose of brevity and clarity, the electronic components are not shown. Also shown are the bottom slotted track channel  120  and the top slotted track channel  156  of the door stop assembly  52  ( FIGS. 3 and 4 ) secured and aligned within the top channel  12   a  and the bottom channel  12   d , respectively. 
       FIG. 6  is an exploded view of the face panel door  36   a  which is closely related to the face panel door disclosed in patent application Ser. No. 11/227,599 filed Sep. 15, 2005, entitled “Electronic Display Panel,” presently pending. The face panel door  36   a  is substantially a one-piece structure having a face panel  54  and opposed side panels  56  and  58  and opposed parallelogram shaped top and bottom panels  60  and  62 , respectively, which are formed at various angles extending inwardly from the face panel  54  the top view of which is shown in  FIG. 13 . The face panel  54  includes a plurality of holes  55   a - 55   n  for viewing of LED pixels located on LED display modules  68  ( FIG. 3 ) The opposed side panels  56  and  58  and opposed top panels  60  and  62  include rearwardly located lips  56   a ,  58   a ,  60   a  and  62   a , respectively, at the rearward portion thereof. The lips  56   a ,  58   a ,  60   a  and  62   a  are parallel to the face panel  54 . Other components of the face panel door  36   a  include the top hinge bracket assembly  38   a  attached to the top surface at one end of the top panel  60  and the bottom hinge bracket assembly  40   a  attached to the bottom surface at one end of the bottom panel  62 . Also attached to the underside of the top panel  60  in close proximity to the top hinge bracket assembly  38   a  is a top pivot bracket  64 , and attached to the upper side of the bottom panel  62  in close proximity to the bottom hinge bracket assembly  40   a  is a similarly structured bottom pivot bracket  66 , where such pivot brackets  64  and  66  are components of the face panel door  36   a  which are used to interface between the face panel door  36   a  and the door stop assembly  52 . Other components of the face panel door  36   a  include the top latch assembly  42   a  attached to the upper forward facing surface of the face panel  54  and the bottom latch assembly  44   a  attached to the lower forward facing surface of the face panel  54 . Another component of the front panel doors  36   a - 36   n  is a seal  70 , preferably of foam or soft rubber or plastic, having a broad base and a low profile for minimum compression distortion which seal  70  is secured to the rearwardly located lips  56   a ,  58   a ,  60   a  and  62   a  for subsequent sealing of the front panel doors  36   a - 36   n  upon closure with structures, such as, but not limited to, portions of the top channel  12   a , the bottom channel  12   d , the end channels  12   b  and  12   c , and portions of the formed channels  14   a - 14   n , respectively. Another component of the front panel doors  36   a - 36   n  is a polycarbonate panel  72 , preferably clear and having hardware accommodation holes, which panel  72  is aligned and secured over rearwardly extending hardware and mates to the rear surface of the face panel  54 . Mirror image configured spacers  74  and  76  (shown separated) and spacers  78  and  80 , shown in intimate contact, are also aligned and secured to the rear of the polycarbonate sheet  72  and over the rearwardly extending hardware of the face panel  54 , as do a plurality of vertically aligned plates  82   a    82   n  where such components are part of the face panel doors  36   a - 36   n.    
       FIGS. 7 and 8  are isometric views showing the attachment of the top hinge bracket assembly  38   a  to the top panel  60  of the face panel door  36   a  and of the attachment of the bottom hinge bracket assembly  40   a  to the bottom panel  62  of the face panel door  36   a , respectively. In  FIG. 7 , one hinge bracket  84  secures to the top channel  12   a  of the frame  12  with suitable fasteners in conjunction with body holes extending through the top channel  12   a  and the hinge bracket  84 . Part of the hinge bracket  84  designated as extension  84   a  extending forward of a reference line  86  on the hinge bracket  84  accommodates part of a vertically oriented pivot assembly  88  extending therethrough. The extension  84   a  of the hinge bracket  84  extending in front of the reference line  86  extends outwardly beyond the upper lipped panel  26   a  of the facia panel  32  (not shown), as well as outwardly and forwardly of the continuous lip  13  in order to provide a suitable spacing for near straight-on compression (as opposed to sliding and deformed contact compression) of the seal  70  when the face panel door  36   a  in a closed position. The top hinge bracket assembly  38   a  also includes another hinge bracket  90  and a plurality of underlying spacers  92  secured to the top panel  60  of the face panel door  36   a  with suitable fasteners in conjunction with body holes extending through the hinge bracket  90 , the plurality of underlying spacers  92 , and the top panel  60 . Part of the hinge bracket  90  designated as extension  90   a  extending forward of a reference line  94  on the hinge bracket  90  accommodates part of the vertically oriented pivot assembly  88  extending therethrough. The extension  90   a  of the hinge bracket  90  extending in front of the reference line  94  extends outwardly beyond the upper lipped panel  26   a  of the facia panel  32  (not shown), as well as outwardly and forwardly of the continuous lip  13  in order to provide a suitable spacing for near straight-on compression as possible (as opposed to sliding and deformed contact compression) of the seal  70  when the face panel door  36   a  is in a closed position. 
       FIG. 8  is an isometric view showing the attachment of the bottom hinge bracket assembly  40   a  to the bottom panel  62  of the face panel door  36   a  in mirror fashion and in the same manner as described for attachment of the top hinge bracket assembly  38   a  to the top panel  60  of the face panel door  36   a , as described in  FIG. 7 . Corresponding like components or references including a hinge bracket  96 , an extension  96   a , a reference line  98 , a pivot assembly  100 , a hinge bracket  102 , an extension  102   a , a plurality of spacers  104 , and a reference line  106  are associatingly attached and/or associated therewith and reflect similar teachings, attributes and relationships as described in  FIG. 7 . 
       FIG. 9  is a segmented isometric view showing a top latch assembly  42   a  secured to the front of the face panel  54  adjacent the top panel  60  of the face panel door  36   a  and, correspondingly, of the bottom latch assembly  44   a  secured to the front of the face panel  54  adjacent the bottom panel  62  of the face panel door  36   a . Inner spacer gaskets  108  are also shown opposite the top and bottom latch assemblies  42   a  and  44   a  at the rear of face panel  54 . With additional reference to  FIG. 10 , structure of the top latch assembly  42   a  is shown in exploded view including a gasket  109  which is aligned with the front of the face panel  54  and other components which are attached substantially to or which are located in front of or in general association with the front region of the face panel  54 , including an outer plate  110 , a channel plate  112 , and a fastener  114 , such as a machine screw or bolt, preferably with a hex head or other configured security head, which extends through a body hole  118  in the outer plate  110 . The channel plate  112  captivates the fastener  114  in the body hole  118  in the outer plate  110 . The features of the head of the fastener  114  are accessible through an access hole  116  in the channel plate  112  in order to facilitate engagement of the fastener  114  with threaded surfaces, such as in a captured nut  47  ( FIG. 5 ) in the top catch assembly  46   a . Suitable hardware mutually secures the top latch assembly  42   a  components, as well as providing means for attachment of the top latch assembly  42   a  to the face panel  54 . Correspondingly, the bottom latch assembly  44   a  is comprised of like components and is in mirror image-like orientation with respect to the top latch assembly  42   a.    
       FIG. 11  is a foreshortened isometric view of the door stop assembly  52  used to lock the face panel door  36   a  or others of such doors in the open position, such as illustrated in  FIG. 12 . Also shown are the top and bottom pivot brackets  64  and  66 , respectively, which are part of the face panel door  36   a . A bottom slotted track channel  120  is secured within a portion of the bottom channel  12   d  of the frame  12  and includes a diagonally oriented slot  122  on the main panel of the track channel  120  which slot  122  intersects and communicates with an arcuate catch  124  located in the main panel wherein the diameter of the arcuate catch  124  is larger than the short dimension across the slot  122 . A bottom latch  126  is an assembly that includes a bolt  128 , a washer  130 , and nuts  132 ,  134  and  136  and is arranged, as shown in  FIGS. 14   a  and  14   b , to slidingly communicate with the slot  122  or the arcuate catch  124 . A bottom cross bar link  138  in the form of a box tube includes a hole set  140 ; i.e. opposed body holes  140  and  140   a  on the top and bottom panels of the cross bar link for the purpose of reversibility for multiple use at one end where the body hole  140   a  accommodates the upper end of the bottom latch  126 , as shown  FIGS. 14   a  and  14   b . Additionally, the opposite end of the bottom cross bar link  138  includes an access hole  142  on the top panel and an opposed body hole  144  for accommodation of a bottom pivot assembly  146  which includes a bolt  148 , a washer  150 , and a nut  152 . The bolt  148  is also accommodated by a hole  154  in the pivot bracket  66 , the latter of which is secured to the bottom channel  12   d  of the frame  12 . Correspondingly, a top slotted channel  156  and a top cross bar link  158  are mirror images of the bottom slotted track channel  120  and of the bottom cross bar link  138 , respectively. The top cross link bar  158  and the bottom cross bar link  138  are connected by a positionable link bar handle  160  which can be angle stock, tube stock or any other suitable geometric configuration suitably secured therebetween. A top latch  162  which is an assembly of a bolt  164 , nuts  166 ,  168  and  170 , and a washer  174  is accommodated by the top slotted channel  156  and by the top cross link bar  158  as shown in  FIGS. 14   a  and  14   b . The top pivot assembly  176 , which is like the bottom pivot assembly  146 , includes a like numbered bolt  148 , washer  150 , and nut  152 , such as used in the bottom pivot assembly  146 , and is accommodated by the body hole  144  in the top of cross bar link  158  and by a hole  178  in the top pivot bracket  64 , the latter of which is secured to the top channel  12   a  of the frame  12 . 
     MODE OF OPERATION 
       FIG. 12  illustrates the door stop assembly  52  in use to hold the face panel door  36   a  in the open position. Illustrated, in particular, is the relationship of the bottom cross bar link  138  which slidingly connect the bottom slotted track channel  120  in the bottom channel  12   d  of the frame  12  to the face panel door  36   a . Such a relationship is also incorporated involving the top cross bar link  158  which slidingly connects the top slotted track channel  156  ( FIG. 11 ) in the top channel  12   a  of the frame  12  to the face panel door  36   a.    
       FIG. 13  is a top view of the face panel doors  36   a ,  36   b  and a portion of the face panel door  36   c  secured to the frame  12  where the face panel door  36   a  is in the open and locked position and where the face panel doors  36   b  and  36   c  are in the closed and locked position, thereby illustrating the open mode and the closed mode with respect to the positioning of the face panel doors  36   a - 36   n . In this view, the top channel  12   a  is removed and the top panel  60  of the face panel doors  36   b  and  36   c  are removed to reveal the structure therebeneath. The parallelogram profile shape of the face panel doors  36   a - 36   n  is evident with reference to the face panel door  36   a  where the top panel  60  (and  62 ) is in the shape of a parallelogram, thereby imparting an angular relationship with the side panels  56  and  58  also shown in  FIG. 6 . As shown in the closed and locked mode, the seal  70  of the face panel door  36   b  is in close and intimate sealing minimally distorted contact with the upper and lower portions of the continuous lip  13  and with the formed channel  14   b  and  14   a . The closed face panel door  36   b  is fixed and secured in the closed position at one edge by the top hinge bracket assembly  38   b  in vertical alignment with the bottom hinge bracket assembly  40   b  and also along the top by the locking of the top latch assembly  42   b  to the top latch assembly  46   b  (not shown), as well as along the bottom by the locking of the bottom latch assembly  44   b  ( FIG. 2 ) to the bottom latch assembly  48   b . The close fit of the face panel doors  36   a - 36   n  is demonstrated where the angled side panel  58  of the face panel door  36   b  is in very close parallel proximity to the angled side panel  56  of the face panel door  36   c , whereby the respective vertical edge regions of the adjacent face panels  54  of the face panel door  36   b  and  36   c  are also in very close parallel proximity to provide nearly gapless alignment to allow smooth and continuous uninterrupted viewing of the LED pixels located on the plurality LED of display modules  68 . Such a relationship is employed along and about the adjacent face panel doors when  36   a - 36   n  are in the closed position. 
     Positioning of the door stop assemblies  52  is also shown in  FIG. 13 . As shown with respect to the closed and locked face panel door  36   b , the top latch  162  is positioned to the left end of the slot  122   a  of the top slotted channel  156 , whereby the door stop assembly  52  is stowed and hidden from view. The same relationship occurs with respect to the bottom latch  126  which is positioned to the left end of the slot  122  of the bottom slotted channel  120 . As shown with respect to the open and locked face panel door  36   a , the top latch  162  is positioned beyond the right end of the slot  122   a  of the top slotted channel  156  and in engagement with the arcuate catch  124   a , whereby the door stop assembly  52  is locked in the open position. The same relationship occurs with respect to the bottom latch  126  which is positioned beyond the right end of the slot  122  of the bottom slotted channel  120  in engagement with the arcuate catch  124 . Positioning of the face panel door  36   a  to the open position is accomplished by disengaging the top and bottom latch assemblies  42   a  and  44   a  from the top and bottom catch assemblies  46   a  and  48   a  and then urging the link bar handle  160  to reposition the top and bottom latches  162  and  126  along the top and bottom slotted channels  156  and  120 , such as shown in  FIGS. 14   a  and  14   b.    
       FIGS. 14   a  and  14   b  illustrate the operation of the door stop assembly  52  and the relationship of the top latch  162  and the top cross bar link  158  to the slot  122   a  and arcuate latch  124   a  of the top slotted channel  156 , as well as the relationship of the bottom latch  126  and the bottom cross bar link  138  to the slot  122  and arcuate latch  124  of the bottom slotted channel  120 . 
       FIG. 14   a  shows the in transit position from a closed position of components of the door stop assembly  52  from the closed and locked position to the open and locked position, as shown in  FIG. 14   b . In  FIG. 14   a , the bolt  164  of the top latch  162  is held securely within the hole  140  of the top cross bar link  158  by the nut  166  and extends through the hole  140   a  and thence through and beyond the slot  122   a . Nuts  168  and  170  are arranged in double nutted fashion and jammed together in frictional engagement and at a fixed position along and about the shaft of the bolt  164  at a position which allows the nut  168  to intimately and supportingly and to slidingly engage the upper surface of the material surrounding the slot  122   a  in order to suspendingly support one end of the top cross bar link  158  with respect to the top slotted channel  156 . In a related fashion, the bolt  128  of the bottom latch  126  is held securely within the hole  140   a  of the bottom cross bar link  138  by the nut  136  and the nut  134 . The nut  132  aligns to the nut  134  in double nutted fashion and jammed together therewith in frictional engagement and at a fixed position along and about the shaft of the bolt  128 . The bolt  128  extends through and beyond the slot  122 . Nuts  132 ,  134  and  136  are arranged in a fixed position along and about the shaft of the bolt  128  at a position which allows the nut  132  to intimately and supportingly and to slidingly engage the upper surface of the material surrounding the slot  122  in order to support one end of the bottom bar link  138  with respect to the bottom slotted channel  120 . The link bar handle  160  is urged in a suitable direction, such as indicated, to cause the top latch  162  to slide along the slot  122   a  and to cause the bottom latch  126  to slide along the slot  122 , while at the same time, urging the top pivot  176  and the bottom pivot  146  ( FIG. 11 ) at the opposite end of the top cross bar link  158  and the bottom cross bar link  138 , respectively, to impart an opening force to rotate the face panel door  36   a  about the top and bottom hinge bracket assemblies  38   a  and  40   a.    
     The door stop assembly  52  is actuated further to the locking position with gravity assisting the locking process when intimate contact of the nut  168  of the top latch  162  with slot  122   a  is discontinued, whereby the nut  168  and  170  of the top latch  162  descend along the arcuate catch  124   a . Such descent is stopped by the washer  174  which engages the material surrounding the arcuate catch  124   a  whereby the nut  170  lockingly engages the arcuate catch  124   a  and is further prevented from entry into the slot  122   a . Thus, the top cross bar link  158  is locked in position. With respect to the bottom latch  126  and associated components thereof, intimate contact of the nut  132  of the bottom latch  126  with slot  122  is discontinued when the nut  132  and  134  of the bottom latch  126  descend into the arcuate catch  124 . Such descent is stopped by engagement of the bottom panel of the bottom crossbar link  138  with the top surface of the bottom slotted track channel  120  when the nut  134  lockingly engages the arcuate catch  124  and is further prevented from entry into the slot  122 . Thus, the bottom cross bar link  138  is locked in position. Unlocking is accomplished by urging the link bar handle  160  upwardly to vertically position the top and bottom crossbar links  158  and  138  to disengage the nuts  170  and  134  from the arcuate catches  124   a  and  124 , respectively, as well as positioning the nuts  168  and  132  for subsequent horizontal sliding and repositioning along the material surrounding the slots  122   a  and  122  upon leftward horizontal positioning of the link bar handle  160 . Such vertical and/or horizontal positioning is limited by contact of the washer  130  of the bottom latch  126  with the underside of the material surrounding the slot  122  or by contact with the underside of the material surrounding the arcuate catch  124  and by contact of the top surface of the top cross bar link  158  with the bottom surface of the top slotted channel  156 . When the link bar handle  160  has been actuated fully to the left in order to reposition the top and bottom cross bar links  158  and  138  to accomplish closing of the face channel door  36   a , the top and bottom latch assemblies  42   a  and  44   a  can then be actuated to lockingly engage the top and bottom catch assemblies  46   a  and  48   a , respectively, thereby securing the face panel door  36   a  in the locked position.