Abstract:
A modular, thin profile backlit display menuboard provides multiple display panels supported at their rear edge against horizontal tracks which provide for support, leveling, and cable ways for simple interconnection of an arbitrary number of display panels to create a flexible menuboard system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application 60/584,285 filed Jun. 30, 2004, and hereby incorporated by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to backlit menuboards and more particularly to menuboards formed from combinations of edge lit display panels.  
         [0003]     Particularly in fast food restaurants, there may be one or more menuboards presenting the restaurant menu and the prices of the menu items offered for sale. Typically, these menuboards consist of a number of display panels showing different photographic reproductions of the items offered for sale, together with prices and description. Quite often these menuboards are backlit with the photograph, letters, and number translucent to emit the light. The backlighting may be contained in a housing behind the display panel which is normally mounted to a wall often specially constructed over the counter.  
         [0004]     U.S. Pat. No. 5,379,540, assigned to the assignee of the present invention and hereby incorporated by reference, describes a modular menuboard where multiple light boxes are abutted side-to-side. Electrical conductors pass through the walls of these boxes allowing electricity to be introduced at one end of the menuboard only to simplify wiring. The modular design allows the menuboard to be provided in different sizes and flexibly expanded if additional menu space is needed in a restaurant.  
         [0005]     Backlit menuboards, using light boxes, are relatively bulky and may not be compatible with the aesthetic concerns of restaurants who want a visually lighter sign system. In such cases, opaque printed placards may be used and illuminated from the front by directional lighting from track lighting or the like. Such an approach entails expense and effort in installing additional lighting to illuminate the signs. Further, front-illuminated signs do not provide the luminosity and color saturation often desired for photographs of food items.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present inventors have recognized that thin profile, backlit menuboards may be constructed by using edge lighting in which a transparent plate is illuminated from the edge and placed behind photographs, text or numbers on translucent sheets to provide for a thin backlight. While such edge illuminated panels are well known, the inventors provide a practical modular system suitable for menuboards through the use of a track which both supports the panels and which provides a cable way allowing jumpers to interconnect separated panels while being hidden within the cable way. The system generally provides a visually light and open menuboard that may be easily installed and expanded without the need for special illumination or complex electrical wiring.  
         [0007]     Specifically, the present invention provides a menuboard system having a set of display panels, each having a transparent plate supporting display elements for backlighting. Lamps at the upper and lower edges of the transparent plate provide for edge lighting of the transparent plate and are covered by shrouds. Rear-facing mounting elements support the panels on a horizontal track having a rear portion mountable on a wall and a front portion receiving the rear-facing mounting elements. A set of electrical jumpers extends between the shrouds to provide sequential electrical connection among the display panels so that power may be introduced to the menuboard system at a display panel at one end of the horizontal track and communicated to a variable number of additional display panels on the track.  
         [0008]     It is thus one object of at least one embodiment of the invention to provide a simple method of collecting a series of edge lit panels into a practical menuboard having reduced installation and wiring costs. The wall tracks allow the panels to be quickly assembled, aligned, and interwired with only a single electrical connection to the power line.  
         [0009]     The rear facing mounting elements may be downwardly extending hooks, and the front portion of the horizontal track may be an upwardly extending flange receiving the downwardly extending hooks.  
         [0010]     Thus it is an object of at least one embodiment of the invention to provide a mounting system that allows for ready adjustment in spacing between the display panels and that flexibly allows multiple numbers of display panels to be installed and removed without extensive remodeling.  
         [0011]     The track may provide a cable guide for the jumpers, for example, a groove in the track opening toward the display panels beneath the upwardly extending flange. A cableway cover may have a downwardly extending lip engaging the upwardly extending flange to fit over the groove.  
         [0012]     It is yet another object of at least one embodiment of the invention to provide an aesthetically acceptable method of connecting power to multiple edge lit panels. Interconnection through the shrouds and supporting tracks provides electrical power to the panels without destroying the visual lightness of the edge lit panels.  
         [0013]     The connectors may be located at four comers of the display panels with upper and lower connectors wired respectively to upper and lower lamp assemblies, and with an intraboard jumper connecting one of the upper connectors to one of the lower connectors, preferably on opposite sides of the display panel.  
         [0014]     It is thus another object of at least one embodiment of the invention provide a method of communicating electrical power from the top shroud to the bottom shroud that also allow simple interconnection between display panels. A simple reconfiguration of the intraboard jumper allows successive panels to be connected at their upper, then lower, then upper edges, in a zigzag pattern.  
         [0015]     Two horizontal tracks may be employed, each having cable guides. Jumpers associated with the upper connectors may be guided by an upper track and the jumpers associated with the lower connector may be guided by a lower track.  
         [0016]     It is another object of at least one embodiment of the invention to provide for short wiring paths that are hidden when following a zigzag pattern of wiring.  
         [0017]     The shrouds may cover only the top and bottom edges of the transparent plate and may be connected by struts extending behind the transparent plate.  
         [0018]     It is thus another object of at least one embodiment of the invention to provide for an easily mounted thin profile backlit panel that preserves a view of the bare edge of the panel preserving the thin profile aesthetic.  
         [0019]     The lamps may be cold cathode fluorescent tubes extending along the upper and lower edge of the transparent plate.  
         [0020]     It is thus another object of at least one embodiment of the invention to provide extremely compact illumination that may be covered by a thin profile shroud.  
         [0021]     The cover on the track covering the wire guide way may abut elements on each of the panels to control the space along the horizontal track between the display panels.  
         [0022]     It is thus another object of at least one embodiment of the invention to allow for simple installation of the panels with an aesthetically pleasing consistency of spacing.  
         [0023]     The cover may be formed from a metal sheet.  
         [0024]     It is thus another object of at least one embodiment of the invention to provide a spacer/cover that may be trimmed using simple tools on site.  
         [0025]     These particular objects and advantages may apply to only some embodiments falling within the claims, and thus do not define the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a front elevational view of a modular sign system according to the present invention showing a number of thin profile display panels supported on horizontal mounting tracks, the display panels including transparent plates positioned between upper and lower shrouds;  
         [0027]      FIG. 2  is a side elevational view in fragment of the upper shroud of the display panel of  FIG. 1  showing an extrusion forming the shroud such as contains a cold cathode fluorescent tube at the top edge of the transparent sheet and which supports plugs for removable jumpers between the display panels such as may fit within a wire guide in the horizontal track and within a display panel passing diagonally along the back;  
         [0028]      FIG. 3  is a top plan view of the shroud of  FIG. 2  showing positioning of the jumper wires within the cable guide of the horizontal track;  
         [0029]      FIG. 4  is a vertical cross sectional view through the track of  FIGS. 2 and 3  showing a guide cover fitting over the cable guide for holding a jumper cable therein;  
         [0030]      FIG. 5  is a simplified, front elevational view of the display panels of  FIG. 1  showing electrical wiring such as allows an alternate high/low or zigzag wiring between each display panel for simplified interconnection; and  
         [0031]      FIG. 6  is a horizontal cross section through the display panel of  FIG. 1  removed from the shroud showing a laminated assembly of the transparent plate, rear reflector, and front film elements, using a simple clamp mechanism. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]     Referring now to  FIG. 1 , a thin profile menuboard  10  may include a number of display panels  12   a  through  12   c  arranged along parallel upper and lower tracks  14   a  and  14   b . The upper and lower tracks  14   a  and  14   b  may be attached one above the other to a wall  16  or the like so as to orient the display panels  12   a  through  12   c  in vertical orientation and spaced horizontally along the tracks  14 .  
         [0033]     The display panels  12  provide an upper and lower shroud  18   a  and  18   b  separated by a transparent panel  20  against whose front surface a photographic film and/or transparent or translucent films containing letters and numbers may be placed to provide menu descriptions and prices. As will be described in greater detail below, each of the display panels  12  may be freely positioned horizontally along the tracks  14   a  and  14   b  restrained only in separation by covers  22  engaging at their left and right edges, track mounts  36  so as to enforce a regular spacing between the panels  12   a  through  12   c  defined by the length of the covers  22 .  
         [0034]     Referring now to  FIG. 2 , the shrouds  18  may be aluminum extrusions or the like having end caps and providing inwardly extending lips  33  that cover the upper and lower edges of the transparent panel  20  and that are attached to front of the transparent panel  20  at those edges to be supported thereby by means of rivets or fasteners  32  passing through the transparent panel  20  and a flange on the lips  33 .  
         [0035]     The shrouds  18  provide a housing containing a cold cathode fluorescent tube  26  aligned with upper and lower edges (only the upper edge is shown) of the transparent panel  20  so that light  28  extending from the generally cylindrical fluorescent tube  26  passes downward throughout the transparent panel  20 . A reflective aluminum tape  35  may hold the cold cathode fluorescent tubes  26  to the edges of the transparent panel  20  so as to direct light into the edge that would otherwise be transmitted away from the edge. The light  28  is internally reflected off of a rear reflective layer  30  attached to the rear face of the transparent panel  20 , as will be described in greater detail below, to provide for a diffuse forward directed light for backlighting of film and the like.  
         [0036]     Referring to  FIGS. 2 and 3 , the shrouds  18  support at their rear surfaces, a pair of vertical struts  34  extending between the upper shroud  18   a  and the lower shroud  18   b , the lower shroud  18   b  being essentially the mirror image of the upper shroud  18   a . The struts  34  are parallel to each other, one on each of the right and left sides of the shrouds  18 .  
         [0037]     Each strut  34  holds on its rear surface two vertically displaced track mounts  36  having downward extending hook portions which may engage an upwardly extending flange  38  on the track  14   a  and  14   b . The upwardly extending flange  38  is spaced away from a wall contacting vertical surface  40  of the track  14   a , the latter which stabilizes the track  14   a  against the wall  16  with the upward flange  38  spaced slightly from the wall to receive the downward hook  52 . The track  14   a  is substantially symmetrical about a horizontal axis also having a downwardly extending flange  42 . The space between the flanges  38  and  42  provides a cable guide groove  44 . Screws or bolts  47  passing through the track  14  into the wall to affix the track  14  to the wall so that the heads of the screws or bolts are contained within the cable guide groove  44 .  
         [0038]     Referring to  FIGS. 2, 3  and  5 , a rear side of each shroud  18   a  and  18   b  supports at their left and right edges electrical sockets  46  that may receive a two conductor plug  48  on a jumper  50 , the latter of which may pass downward into the cable guide groove  44  and there along to a second display panel  12  to be received by a second socket  46  at a corresponding second plug  48  on the jumper  50 . The vertical strut  34  provides an offset of the track mounts  36 , spacing the shroud  18  away from the wall  16 , to allow clearance for the plug  48 .  
         [0039]     As shown in  FIG. 4 , the length of the jumper  50  between the display panels  12  may fit within the cable guide groove  44  beneath a cover  22  fitting over the track  14 . The cover  22  has a downwardly extending hook  52  engaging the upwardly extending flange  38  and a downwardly extending front portion  54  covering the cable guide groove  44  to provide protection to and covering of the jumper  50  in between the display panels  12  fully hiding interconnecting wiring. The covers  22  may be fabricated of sheet metal, and therefore may be trimmed with shears in the field to provide for variations and separations of the display panels  12 , any irregularity in the trimming being covered by the display panels  12  themselves. The tracks  14  may be installed with simple carpentry skills and eliminate the need for difficult wiring within the wall.  
         [0040]     Referring to  FIG. 5 , by providing sockets  46  in each of the top left and right, and bottom left and right edges of the display panels  12  on the shrouds  18 , an interconnection between display panels  12  can be performed at top edges by jumpers  50   a  and at bottom edges by jumper  50   b  for an arbitrary number of display panels  12 . Wiring internal to the top shroud  18   a  passes from an upper left socket  46  to the cold cathode fluorescent tube  26  at the top of the display panel  12  (specifically to a power supply feeding the cold cathode fluorescent tube  26 , but not shown for clarity), then to the rightmost socket  46 .  
         [0041]     In this case, where jumper  50   a  is connected to the top left edge of the shroud  18   a , a diagonal jumper  60  may be connected to the socket  46  on the upper right side of shroud  18   a  to socket  46  on the lower left side of shroud  18   b.    
         [0042]     The socket  46  on the lower left side of the shroud  18   b  is then connected to the lower cold cathode fluorescent tube  26  (power supply), and then to the socket  46  on the lower right hand side used with jumper  50   b  to connect to display panel  12   c.    
         [0043]     It will be understood that in the next connected display panel  12   c , the jumper  60  (not shown) may be connected to the socket  46  on the upper left side of shroud  18   a  to socket  46  on the lower right side of shroud  18   b.    
         [0044]     Each of jumpers  50   a  and  50   b  may be fed through the guide way formed by cable guide groove  44  shown in  FIG. 4  in different of the tracks  14   a  and  14   b.    
         [0045]     Referring now to  FIG. 6 , the transparent panel  20  may, for example, be Lexan or other clear plastic material. A photographic film  62  or transparent lettering may be attached to the front face of the transparent panel  20  for transmission of light therethrough and a reflective layer  30  at its rear face for reflecting light toward the front face. As is well known in the prior art, a series of grooves  64  or light absorbing or light reflecting stripes may be placed on the rear surface of the transparent panel  20 , for example, having variation in depth or width proportional to the falloff in light as light passes downward or upward from the cold cathode fluorescent tube  26  to provide a more even illumination from light directed forward out of the transparent panel  20 .  
         [0046]     The film  62  may be held to the front of the transparent panel  20  by means of a spring clip  68 , for example, an elongate C-shaped plastic channel that may clip over the edges of the transparent panel  20  allowing both retention and removal of the film  62 . The spring clip  68  is essentially the size of the edge of the transparent panel  20  so as to provide and preserve the thin profile aesthetic of the display panels  12 . A reflective aluminum tape  66  may be placed on the edges of the transparent panel  20  so as to return light that would otherwise be transmitted out of the edge.  
         [0047]     Display panels  12  may also be suspended on a serpentine channel or suspended channel as described in co-pending U.S. application Ser. No. ______, entitled Serpentine Menu Board System, and assigned to the same assignee as the present invention and hereby incorporated by reference.  
         [0048]     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.