Abstract:
The invention concerns a scrolling poster display device, comprising two parallel rolls, a poster strip wound on the rolls and a support device for supporting the rear side of the poster strip between the rolls. The support device comprises an air chamber delimited by a peripheral frame and a base offset rearward, and an air blowing device generates an excess pressure of air in the air chamber.

Description:
FIELD OF THE DISCLOSURE 
   The present invention relates to scrolling poster display devices. 
   More specifically, the invention relates to a scrolling poster display device comprising:
         at least two parallel rollers,   poster strip wound onto the rollers, said poster strip having a front face visible to the public and a rear face on the opposite side to the front face,   at least one motor for driving the rollers,   and a fixed support device designed to shape the rear face of the poster strip between said rollers.       

   BACKGROUND OF THE DISCLOSURE 
   Document U.S. Pat. No. 5,174,055 describes a display device of this type, in which the rear face of the poster strip rests against a solid support panel which extends over the entire surface of this poster and in particular allows the poster to be given a curved shape. This display device has the following disadvantages in particular:
         the rubbing of the posters or of their support strip against the bearing panel may wear and/or soil the posters or their support strip,   this rubbing generates static electricity which causes the posters to adhere to the bearing panel, thus impeding the correct scrolling of the posters and possibly even causing them to tear.       

   SUMMARY OF THE DISCLOSURE 
   To this end, according to the invention, the support device comprises an air chamber delimited by a peripheral surround adjacent to the rear face of the poster strip and a back which is offset rearward with respect to the surround, said support device comprising no element near the rear face of the poster strip inside the surround,
         and the display device further comprises at least one air-blowing device able to create a raised air pressure in the air chamber, the air injected into the air chamber escaping to the exterior thereby forming a layer of air at the interface between the surround and the rear face of the poster strip.       

   By virtue of these measures, the poster strip is filled with the blown air, giving it a shape corresponding to the shape of the surround. In addition, practically all contact between the rear face of the poster strip and the support device is avoided because of the creation of a layer of air between the surround and the poster strip. The aforementioned disadvantages of the prior art are thus avoided. 
   In some preferred embodiments of the invention recourse may also possibly be had to one and/or other of the following measures:
         the poster strip is substantially impervious to air;   the poster strip is kept under tension;   the poster strip is kept under tension by the rollers;   the rollers are substantially vertical;   the surround comprises two opposite first sides substantially perpendicular to the rollers, which have a convex overall shape with the bulge facing forward so that the poster strip itself exhibits a convex shape with the bulge facing forward between the rollers;   the two first sides of the surround have identical shapes;   the two first sides of the surround each have a front face adjacent to the rear face of the poster strip, of width of between 5 and 12 cm;   the surround also comprises two second sides substantially parallel to the rollers, said second sides each having a rounded front edge;   the display panel comprises an electronic control unit which controls the rollers and which is designed to release the tension in the poster strip partially when said poster strip is set in motion by the rollers.       

   Other features and advantages of the invention will become apparent in the course of the following description of an embodiment thereof, given solely by way of nonlimiting example with reference to the attached drawings, 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  is a perspective view of a display device according to one embodiment of the invention; 
       FIG. 2  is a perspective view from the front, of a poster support belonging to the display device of  FIG. 1 ; 
       FIG. 3  is a partial view in horizontal section of the poster support of  FIG. 2 ; 
       FIG. 4  is a perspective view from the rear of the poster support of  FIG. 2 ; and 
       FIG. 5  is a block diagram of the display device of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   In the various figures, the same references denote elements which are identical or similar. 
     FIG. 1  depicts a display device  1  consisting, for example, of a pillar of cylindrical overall shape comprising a support structure  2 , fixed to the ground, and optically transparent windows  3 , for example, in the form of portions of a cylinder. 
   Posters belonging to a scrolling poster strip  4  are displayed in each window  3 . 
   The poster strip  4  is wound onto two parallel rollers  5 , for example vertical rollers, just one of which can be seen in  FIG. 1 . 
   These rollers are motor driven and are controlled by an electronic control unit as described in greater detail hereinafter, so that the posters that form the poster strip  4  can scroll past in sequence so that each of these posters can be displayed in turn in the window  3 . 
   Between the rollers  5  there is a poster support device  6 , fixed to the support structure  2 , and which is designed to support the rear face of the poster strip  4 , that is to say that face of this poster strip that is not visible to the public. 
   As can be seen in  FIGS. 1 to 3 , this support device  6  has the overall shape of a portion of a cylinder of vertical axis and with the bulge facing toward the outside of the display device, that is to say forward. 
   More specifically, this support device  6  comprises a surround  7  which comprises:
         two horizontal first sides  8 , these being an upper side and a lower side respectively, in the overall form of arcs of a circle, and   two straight and vertical second sides  9 .       

   Each of the first sides  8  has a front face  8   a  in the form of a portion of a cylinder, which is adjacent to the rear face of the poster strip  4  and which has a width h in the vertical direction. This width h ranges, for example, between 5 and 12 cm and may in particular be of the order of 10 cm. 
   Furthermore, each of the second sides  9  comprises a front edge  9   a  (see  FIG. 3 ) which is adjacent to the rear face of the poster strip  4  and which may be relatively thin, for example having a width ranging between 5 and 10 mm, This front edge  9   a  is preferably of rounded cross section, as can be seen in  FIG. 3 . 
   The support device  6  further comprises a back  10  which may advantageously be produced as a single piece with the surround  7 , for example in translucent Plexiglas® or the like The back  10  has the overall shape of a section of a cylinder and may itself have a thickness ranging for example between 5 and 10 mm. The back  10  is positioned set back rearward from the front faces  8   a  and from the front edges  9   a  of the surround, in order together with the surround  7  to delimit an air chamber  11  of depth P ranging for example between 2 and 4 cm, and for example of the order of 3 cm. 
   Formed in the back  10  of the poster support  6  are one or more openings  12  each of which communicates with a blower  13  situated behind the back  10 , as depicted in  FIG. 4 . Each of the blowers  13  constantly blows air into the air chamber  11  in order to create a slight raised pressure, for example of the order of 20 to 30 Pa, therein. This raised pressure “fills” the poster strip opposite the air chamber  11  and gives it a cylindrical shape corresponding to the overall shape of the support device  6 . 
   In addition, this raised pressure creates a small air leak around the entire periphery of the support device  10 , between the surround  7  and the rear face of the poster strip  4 , especially since the poster strip is generally made of a material that is substantially impervious to air. This leak creates a permanent layer of air separating the rear face of the poster strip  4  from the support device  6 , thereby avoiding or, at the very least, limiting, rubbing between said rear face of the poster strip and the support device  6   
   As can be seen in  FIG. 4 , illuminating devices  14 , for example fluorescent tubes, may also be fixed to the rear face of the back  10  so as to back-light the poster while it is being displayed through said back  10 , which is preferably translucent 
   Moreover, electric motors  15 , for example asynchronous motors, may also be housed behind the back  10 , each of these driving one of the rollers  5  via a transmission device, for example a belt  16 . 
   These motors can be controlled for example as described in document FR-A-2 812 750, using two variators  17  (VAR 1 , VAR 2 ) visible in  FIG. 5 , controlled by an electronic control unit  18  (AUT) such as an industrial controller or the like When the poster strip  4  is scrolled horizontally in order to change the poster being displayed, the poster strip is tensioned slightly as power is supplied to the motor of the roller driving the rolled poster strip at a frequency slightly higher than the other roller 
   Advantageously, the controller  18  may be designed:
         so that this tension is relatively slight during the scrolling movement (corresponding, for example, to a frequency difference of 1 to 2 Hz across the variators  17 ), and   to increase this tension when the poster strip stops.       

   As can be seen in  FIG. 5 , the controller  18  may also control the blowers  13  (V 1 , V 2 ) and may also be connected to a sensor  19  (C), known per se, designed to detect identifiers on the poster strip so that the scrolling of this strip is halted in correspondence with the posters that it bears.