Patent Publication Number: US-7895782-B2

Title: Light box display apparatus configured for frontal access

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of light box displays of the type used to present advertising comprising a replaceable graphics sheet positioned in front of a diffused light source. The invention pertains more specifically to such a light box uniquely configured to provide access only from the front of the display such as for changing the graphics or performing maintenance on the light box. 
     2. Background Art 
     Light boxes of the type disclosed herein have been in widespread use for at least the past forty years. See for example issued U.S. Pat. Nos. 3,390,259 and 3,391,481, both issued in 1968. Typically, such light boxes provide a rectangular housing having a distributed light source such as a plurality of spaced fluorescent tubes and a diffusing transparent or translucent surface for spreading the light evenly across the housing where it exits from a rectangular opening. Some form of graphics are provided either printed directly on the diffusing surface or on a flexible graphics sheet which is placed immediately in front of the diffusing surface. 
     In recent years, such light box displays have become more common as advertising systems as opposed to signs. Typically, advertising light boxes are wall mounted inside retail stores or where there is a great deal of foot traffic such as in airports, train stations, indoor malls and the like. Advertising light box displays normally utilize changeable graphics so that their advertising content can be modified relatively often. Such graphics are usually provided as a unitary flexible plastic film vinyl, paper, fabric or other substrate which has the advertising indicia printed on it and which is inserted into the light box in contiguous relation to the diffusing surface in front of the lighting source. The current trend appears to be to make such advertising light box displays quite large, such as four to six feet in height and eight to sixteen feet in length. They&#39;re typically four to twelve inches in thickness or depth. Conventional light box displays are simply affixed to the exterior surface of a wall. However, given the considerable cost of retail space, there is a growing desire to install light box displays inside recesses of a wall so that they don&#39;t extend beyond the wall&#39;s exterior surface. Such installations however create problems relating to access to the light box interior which is necessary to change out graphics and to perform maintenance such as replacing burned out light bulbs. Such access is normally gained from the side or rear of the light box or from a removable front element. However, side or rear access usually complicates the structure of the light box making it more expensive to manufacture. More importantly, side or rear access may require either that the light box be capable of being removed from its recess (which has significant impact on aesthetics and maintenance costs) or that some structural modifications be made to the surrounding wall to allow personnel to gain such access (which increases construction cost and may require wasteful use of costly retail space). Moreover, some retailers may wish to provide flush mounted light box surfaces which are overlapped by adjacent wall surfaces for aesthetics, thereby making it virtually impossible to provide front, side or rear access to the light box display. 
     Not having side or rear access to a flush mounted light box display, means that one must have frontal access to change the graphics and perform maintenance tasks. However, with the sheet of graphics being as large as the light box frontal area and being mounted flush with the front surface of the light box, it is not immediately apparent how to gain frontal access to replace the graphics or perform maintenance tasks. This is the problem that is addressed by the present invention. 
     SUMMARY OF THE INVENTION 
     The present invention, in its preferred embodiment, comprises a light box display configured for frontal access to change out graphics and to perform maintenance tasks. This is accomplished in the present invention while assuring that the graphics is held in a state of moderate tension to retain the graphics in a flat and properly oriented configuration. 
     In the preferred embodiment, the light box comprises a moveable interior frame to which the graphics sheet and diffuser are both secured. The moveable interior frame rests on a plurality of upper and lower slides which facilitate movement of the inner frame. Such movement is controlled, in part, by at least one pneumatic piston which biases the frame toward the front of the light box and provides a mechanical lock that holds the frame in its rearward position to facilitate frontal access. The graphics sheet is held in place along the top and bottom front peripheral edges of the moveable frame by a plurality of spring-biased wire connection members within roller glides. One end of each wire member is attached to the rear peripheral surface of the moveable inner frame and the other end is threaded through a grommeted hole along the outer edge of the graphics sheet. Side spring-biased wire connection members are also provided. The side wire members are interconnected to a common manual latch. This latch is closed to pull the sides of the graphics sheet taut and opened to release the sides of the graphics sheet when it is desired to push the moveable frame back to gain access to the light box interior. In other respects, the light box is relatively conventional in its operation in that it has a plurality of spaced apart fluorescent light tubes located towards the rear interior surface of the light box behind the moveable frame. 
     By employing a novel combination of a moveable interior frame, pneumatic pistons and spring-biased graphics sheet interface members, the disclosed embodiment provides a light box that is uniquely accessible from the front while assuring properly displayed graphics. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned objects and advantages of the present invention, as well as additional objects and advantages thereof, will be more fully understood herein after as a result of a detailed description of a preferred embodiment when taken in conjunction with the following drawings in which: 
         FIG. 1  is a perspective view of a preferred embodiment of the present invention; 
         FIG. 2  is a view similar to that of  FIG. 1 , but showing certain components partially cut away to reveal the interior of the preferred embodiment; 
         FIG. 3  is a front plan view of the preferred embodiment with the graphics sheet removed and the diffuser sheet partially cut away; 
         FIG. 4  is a downwardly directed cross-sectional view of the invention showing the inner frame moved toward the back of the apparatus to gain access to the interior; 
         FIG. 5  is a cross-sectional view similar to that of  FIG. 4  with the inner frame moved toward the front opening for normal display operation of the apparatus; 
         FIG. 6  is a side-directed cross-sectional view showing the front access condition; 
         FIG. 7  is a side-directed cross-sectional view showing the normal display condition; 
         FIG. 8  is a front view of a connection member and connection guide of the preferred embodiment; 
         FIG. 9  is a top view of the connection member and connection guide; 
         FIG. 10  is an enlarged side cross-sectional view showing a portion of the inner frame in the access condition and a graphics sheet ready for attachment within the light box display apparatus; 
         FIG. 11  is a view similar to  FIG. 10 , but showing the normal display condition; 
         FIG. 12  is a cross-sectional side view showing the side connection members of the invention; 
         FIG. 13  is an enlarged interior side view of the side connection member interface; 
         FIG. 14  is an enlarged cross-sectional view taken along lines  14 - 14  of  FIG. 12 ; 
         FIG. 15  is a cross-sectional plan view of the side connection member/latch interface; 
         FIG. 16  is an enlarged view of an inner frame guide rail; and 
         FIG. 17  is a plan view of the entire light box display apparatus shown during installation of a graphics sheet. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring to the accompanying drawings, it will be seen that a light box display apparatus  10  comprises a housing or outer frame  12  of substantially rectangular shape and forming a large front opening  15 . As seen best in  FIGS. 1 and 2 , the apparatus  10  provides a graphics sheet  14  in front of a diffuser sheet  16 . Sheets  14  and  16  fill the entire front opening  15  and reside in front of a light source comprising a plurality of fluorescent light bulb tubes  18  which are preferably positioned in a space apart parallel arrangement adjacent the back interior surface  21  of outer frame  12 . 
     Referring to  FIGS. 3 through 7 , it will be seen that the light box display apparatus  10  also comprises an inner frame  20  which is located entirely within the outer frame  12  and is almost as long as the interior of the outer frame and only slightly shorter in height. The inner frame is oriented to be substantially parallel to the interior back surface  21  and moveable between the back surface and the front opening  15 . The inner frame  20  moves on a plurality of guide rails  24  positioned along the top and bottom interior surfaces of the outer frame  12 . Movement of the inner frame  20  is controlled by a number of pneumatic pistons  22  which are interconnected between the inner frame  20  and the interior top and bottom surfaces of the outer frame  12  as shown bets in  FIGS. 3 ,  4  and  5 .  FIGS. 6 and 7  respectively illustrate rearward and forward positions of the inner frame  20  within the outer frame  12 . 
     Referring to  FIGS. 8 through 11 , it will be seen that apparatus  10  also comprises a plurality of spring-biased connection members  25  which are threaded through respective connection guides  26 , the latter having a number of cylindrical rollers  32  for guiding the connection members  25  from the rear surface of inner frame  20  to the front thereof. Each such spring-biased connection member  25  includes a spring  27  and a retainer  29 . The spring end of each connection member  25  is connected to the inner frame  20  at a diffuser bracket  17  which supports the diffuser sheet  16 . The retainer end of the connection member  25  is threaded through a grommeted hole  13  along the edge portion of graphics sheet  14  as shown best in  FIGS. 10 and 11 . Those having skill in the art of light box displays, will understand from observing  FIGS. 8 through 11 , that as inner frame is moved away from front opening  15  and toward interior back surface  21  of outer frame  12 , each connection member  25  becomes slack, thereby permitting retainer  29  to be released from grommeted hole  13  of graphics sheet  14 . This connection member slacked condition is depicted best in  FIG. 10 . In this condition of apparatus  10 , personnel may reach through front opening  15  and release graphics sheet  14  from inner frame  20 , such as for replacement. Personnel may also gain access to fluorescent bulb tubes  18  and remove any one or more of them from their respective mating receptacles  19  such as for replacement. 
     On the other hand, it will be observed that as the inner frame  20  is moved toward the front opening  15 , the connection members  25  become taut with the retainer  29  threaded through the grommeted holes  13  of graphics sheet  14 . Thus, the graphics sheet  14  is subjected to a level of surface tension at various locations along the upper and lower surfaces of inner frame  20  thereby securing the graphics sheet in its appropriate position within the light box display apparatus  10 . 
     Movement of the inner frame  20  along guide rails  24  (see  FIG. 16 ) is controlled by pistons  22 , each of which provides a locking device  34  which permits personnel to lock the frame  20  along its path of motion when the frame  20  is closest to interior back surface  21  (See  FIG. 4 ). 
     The side edges of the graphics sheet  14  are also held in tension during normal display operation. As seen best in  FIGS. 12 through 15 , this is done somewhat differently in that side-connection members  30  are channeled through a channel bar  36  and respective connection guides  38  (each having rollers  32 ) to a manual latch  28  as shown in  FIG. 15 . Each side-connection member  30  is also spring-biased and provided with an end retainer to mate with a grommeted hole in the graphics sheet. However, the side connection members are not connected to the inner frame  20 . It has been determined that manual latch  28  is the preferred means for controlling the side-directed tension on the graphics sheet  14  as opposed to the travel position of the inner frame  20 . Therefore, when it is desired to release the graphics sheet  14  for replacement, as the inner frame is pushed back toward interior back surface  21 , the latch  28  becomes accessible and is used to release the side tension after the inner frame is pushed to its fully rearward position. 
       FIG. 17  illustrates installation of a new graphics sheet  14  while latch  28  is opened and inner frame  20  is in its access condition. Once all of the retainers  29  have been threaded through corresponding grommeted holes  13 , the latch  28  is closed and the frame  20  is pushed to be flush with the front opening  15 . 
     Having thus disclosed a preferred embodiment of the present invention to enable fabrication and operation of the inventive light box display apparatus, it will be evident that various modifications can be readily made. By way of example, the invention herein can be modified to accept graphics sheets that are placed in tension in other ways, or that are self-tensioned such as by being attached at their edges using a beaded edge captured in a trough-like recess of the margin of the inner frame, or which do not require tension at all. Such modifications would still benefit from the inventive feature herein of frontal access by means of a movable inner frame. Therefore, it will be apparent that the scope hereof is to be deemed limited only by the appended claims and not by the illustrative embodiment disclosed herein.