Patent Publication Number: US-2006000879-A1

Title: Case comprising a rigid face and a flexible face able to be closed and maintained in the closed state

Description:
The invention concerns a case produced by folding a complex comprising a sheet of thin flexible material and a sheet of thick rigid material, a blank intended for producing such a case, and a method of producing such a blank.  
      There are known, from the document WO 02/00424, packages obtained after folding a sheet consisting of a stack of a layer of flexible material and a rigid layer. To enable it to be folded, the sheet comprises a groove produced in the rigid layer and whose height is equal to the thickness of the rigid layer.  
      However, manufacturers have not envisaged producing packages comprising closure lugs for obtaining closed volumes. Embodiments of the “matchbox” type have been envisaged, that is to say with a container inserted in a package of the type described above. However, such designs in several pieces are not practical, in particular in the case of the loss of one of the pieces, which makes the package unusable.  
      The document U.S. Pat. No. 5,065,935 describes a box covered with a packaging paper comprising lateral panels folded over one opening of the box and held by slots inserted in one another.  
      This type of closure is complex to produce for a package comprising a rigid layer and does not make it possible to keep it firmly closed.  
      There is also known from the document EP-A-0 709 293 a box comprising a closure panel. A tongue separated from the panel by a folding line comprises openings through which hooks provided on foldable lugs pass when the box is closed.  
      However, this type of closure, requiring the deformation of the hooks to open the box, is not suitable for a package comprising a rigid layer as it might damage the package.  
      The invention aims to permit the production of a package comprising a layer of flexible material and a rigid layer able to be closed and maintained firmly in the closed state using the rigidity of the rigid layer.  
      To this end, and according to a first aspect, the invention concerns a case produced by folding a complex, the said complex comprising a sheet of flexible thin material such as cardboard or plastics material with which there is associated a sheet of rigid thick material such as wood or metal, the said case comprising: 
          a body comprising lateral panels, including at least one front panel and one rear panel,     at least one first opening defined by the said lateral panels, some of the edges of the said opening each carrying a lateral lug folded at right angles with respect to a lateral panel of the case along a folding line, the said lateral lugs comprising a rigid step close to the said folding line and projecting towards the front panel of the case, 
 
 the said case also comprising at least one lug closing the opening at one of the ends of the body, the said closure lug comprising an opening/closing panel articulated on the rear panel along a folding line, the said opening/closing panel comprising, at its end opposite to the folding line, an entering lug foldable at right angles with respect to the said opening/closing panel along a folding line substantially parallel to the folding line, the folding line comprising in its end parts a removal of material through each of the sheets in the complex, the rigid steps on the lateral panels being inserted in the removals of material when the closure lug is folded over the opening so as to obtain, because of the rigidity and thickness of the sheet of rigid thick material, a snapping of the rigid steps into the removals of material in order to lock the said closure lug in the position of closure of the case. 
       

      According to a second aspect, the invention concerns a blank intended for producing a case as described above, this blank being produced from a complex comprising a sheet of flexible thin material such as cardboard or plastics material with which there is associated a sheet of rigid thick material such as wood or metal, the said blank comprising: 
          lateral panels, including at least one front panel and one rear panel, separated by folding lines and defining the body of the case by folding,     lateral lugs adjacent to some of the lateral panels and articulated on these by folding lines,     a gluing lug adjacent to the front panel and articulated on this by a folding line substantially parallel to the folding line separating the lateral panels, 
 
 the said blank also comprising an opening/closing panel adjacent to the rear panel and articulated on the said rear panel by a folding line, the said opening/closing panel comprising, at its end opposite to the folding line, an entering lug, the said lug being articulated on the opening/closing panel by a folding line substantially parallel to the folding line, the folding line comprising, in its end parts, a removal of material, the folding lines being produced by cropping the sheet of rigid material in the complex. 
       

      According to a third aspect, the invention concerns a method of producing a blank as described above, the said method comprising the following steps: 
          producing a complex by associating a sheet of flexible thin material such as cardboard or plastics material and a sheet of rigid thick material such as wood or metal;     cropping the complex so as to form the lateral panels, the closure lug, the gluing lug and the lateral lugs;     producing the folding lines by cropping the sheet of rigid material only;     producing a cut in the sheet of rigid material close to the removals of material, the said cut extending partially over the opening/closing panel and over the entering lug;     producing removals of material by complete cutting of the complex.       

    
    
      Other objects and advantages of the invention will emerge during the following description given with reference to the accompanying drawings, in which:  
       FIG. 1  is a plan view of the internal face of a blank according to one embodiment of the invention;  
       FIG. 2  is a perspective view of a case with its closure lug open, issuing from the making up of the blank according to  FIG. 1 . 
    
    
      In relation to  FIG. 1 , a blank  1  is described produced from a complex comprising a sheet of flexible thin material, such as cardboard or plastics material, and a sheet of rigid thick material, such as wood or metal. Flexible thin material means a sheet produced from a material whose nature and thickness make it possible to deform the sheet. Sheet of rigid thick material means a sheet produced from a material whose nature and thickness limit the deformation of the sheet. In particular examples, the thickness of the sheet of flexible material is around a few tens of millimetres and that of the sheet of rigid material is around twice that of the sheet of flexible material.  
      The internal face  3  of the blank  1  is defined as being the face of the blank which will be situated inside the case  2  when the blank is made up, the external face  4  forming the visible face of the case  2  when the latter is formed.  
      According to the invention, the sheet of flexible thin material forms the internal face  3  of the blank  1  and the sheet of rigid material forms the external face  4 . There is thus conferred on the case  2  an external appearance with a particular aesthetic appeal according to the material chosen for the sheet of rigid material. It is also possible to print various bits of information on the external face  4 , for example a logo or the like.  
      The blank  1  comprises lateral panels, including at least one front panel  5  and one rear panel  6 .  
      According to the embodiment depicted, a first lateral panel  7  is articulated on the rear panel  6  by a folding line  8 . On the side opposite to this folding line  8 , a second lateral panel  9  is articulated on the rear panel  6  by a folding line  10 . On the side opposite to this folding line  10 , the second lateral panel  9  is articulated on the front panel  5  by a folding line  11 .  
      The set of lateral panels  5 ,  6 ,  7  and  9  define the body  36  of the case with a cylindrical shape overall, for example substantially parallelepipedal, when the blank  1  is made up. According to other embodiments which are not shown, it is possible to envisage interposing additional lateral panels between the front  5  and rear  6  panels in order to produce cases with different shapes. Moreover, it is possible to provide for at least one lateral panel  5 ,  6 ,  7  and/or  9  to comprise an opening produced by a cut in the complex.  
      The lateral panels are substantially polygonal, for example rectangular, and the folding lines separating the lateral panels are substantially parallel to each other. It is however possible to provide for the panels to have a trapezoidal shape so as to form a case having an inclined opening.  
      On the side opposite to the folding line  11 , a gluing lug  12  is articulated on the front panel  5  along a folding line  13  substantially parallel to the folding lines  8 ,  10  and  11 .  
      An opening/closing panel  14  is adjacent to the rear panel  6  and articulated on this along a folding line  15  substantially perpendicular to the folding lines separating the lateral panels. The opening/closing panel  14  has a substantially rectangular shape where the length of the large side corresponds substantially to the length of the small sides of the lateral panels  7  and  9 .  
      An entering lug  16  is articulated on the opening/closing panel  14  at its end opposite to the folding line  15 . The entering lug  16  can be folded at right angles with respect to the opening/closing panel  14  along a folding line  17  substantially parallel to the folding line  15 . The assembly consisting of opening/closing panel  14  and entering lug  16  form a closure lug intended to close the case  2  when the blank  1  is made up.  
      To make it possible to lock the closure lug without damaging the case, the folding line  17  comprises, at each of its end parts, a removal of material  18 . These removals of material  18  consist of complete cuts of the complex comprising the sheet of flexible material and the sheet of rigid material. The cuts being produced through each of the sheets of the complex, the edges of the removals of material  18  have a certain rigidity and a certain thickness. They extend along the folding line  17  towards the centre of the closure lug, having dimensions which are small compared with the length of the folding line  17 .  
      Close to the removals of material  18 , the folding line  17  comprises a cut  19  produced solely in the sheet of rigid material. The cut  19  is substantially perpendicular to the folding line  17  and extends partially over the opening/closing panel  14  on the one hand and over the entering lug  16  on the other hand. The cut  19  marks the end of the removal of material  18 . The cut  19  also comprises, on the side of the opening of the closing panel, a wing  20 . This wing  20 , produced in the sheet of rigid material, is intended to form a projection substantially perpendicular to the opening/closing panel  14  when the entering lug  16  is folded at right angles with respect to this panel  14 , as depicted in  FIG. 2 . Thus the cut  19  stiffens the folding line  17  close to the removals of material  18 . It prevents the removal of material  18  from tearing and “propagating” along the folding line when the case  2  is handled.  
      The entering lug  16  can have rounded edges  21  in order to facilitate its insertion when the closure lug is closed.  
      Lateral lugs  24  and  25  are adjacent to and articulated respectively on opposite edges situated on each side of the rear panel  6 , for example the lateral panels  7  and  9 , through folding lines  26  and  27 . These lateral lugs extend on the same side as the opening/closing panel  14  and have a substantially trapezoidal shape. The folding lines  26  and  27  form the large bases of the trapezia. Close to the folding lines  26  and  27 , the lateral lugs  24  and  25  each comprise a step, respectively  28  and  29 . These steps  28 ,  29 , comprising a part of the sheet of flexible material and a part of the sheet of rigid thick material, are themselves rigid and thick. These rigid steps project towards the front panel  5  when the blank  1  is made up. Their function will be described in relation to the description of the case  2 .  
      According to the embodiment depicted in  FIGS. 1 and 2 , the blank  1  comprises a second closure lug  22  articulated on the rear panel  6  through a folding line  23 , on the opposite edge to the folding line  15  of the rear panel  6 . Lateral lugs  30  and  31  are provided on the opposite sides to the folding lines  26  and  27  of the lateral panels  7  and  9 . Folding lines  32  and  33  separate the lateral lugs  30  and  31  from the lateral panels  7  and  9 . These lateral lugs  30  and  31  also comprise rigid steps projecting towards the front panel  5  when the blank  1  is made up.  
      All the folding lines of the blank  1  are produced by cutting the sheet of rigid material solely and tracing lines on the sheet of flexible material. This type of cut is referred to as a “half-way cut”, only one of the two sheets in the complex being cut.  
      A method of producing a blank  1  as described above is now described.  
      The first step of the method consists of producing the complex comprising sheets of flexible thin material, such as cardboard or plastics material, and a sheet of rigid thick material, such as wood or metal or plastic.  
      The sheet of rigid material and the sheet of flexible material are associated by fixing the sheet of rigid material to one of the faces of the sheet of flexible material. This fixing is for example provided by gluing the sheet of rigid material to the sheet of flexible material.  
      Next the complex is cut so as to form the lateral panels, the closure lug or lugs, the gluing lug and the lateral lugs.  
      The sheet of rigid material is cut along the folding lines and the folding lines are traced on the sheet of flexible material. The blank  1  thus has conferred on it the flexibility necessary for its folding and its making up around the folding lines.  
      The cut  19  can also be made by cutting the sheet of rigid material during this step.  
      The removals of material  18  are then performed by complete cutting of the complex.  
      With reference to  FIG. 2 , a description is now given of the case  2  produced by folding a complex as described above, the said complex having been produced and cut according to the method described above in order to form a blank  1 .  
      The case  2  is therefore produced by making up the blank  1 , which is folded along the folding lines. It should be noted that the gluing lug  12  makes it possible to fix the front panel  5  to the lateral panel  7  so as to maintain the volume formed by the folding of the blank  1 .  
      The blank  1  is folded so that the sheet of flexible material forms the internal face  3  of the case and the sheet of rigid material forms its external face  4 .  
      The making up of a blank  1  like the one depicted in  FIG. 1  forms a case with a substantially parallelepipedal shape comprising a body  36  formed by the lateral panels  5 ,  6 ,  7  and  9 , two openings, one of which  34  is visible in  FIG. 2 , defined by the edges of the lateral panels  5 ,  6 ,  7  and  9 . According to a particular embodiment, the body of the case can comprise an opening produced by a cutting of the complex.  
      The lateral lugs  25  and  24  are folded at right angles with respect to the lateral panels  7  and  9 , so that they partially cover the opening  34 . The rigid steps  28  and  29  of these lugs then project towards the front panel  5  and are situated close to the folding lines  26  and  27 .  
      The folding lug is folded above the opening  34 , so that the opening/closing panel covers this opening when it is wished to close the case  2 . To this end, the dimensions of the opening/closing panel are adapted to correspond to those of the opening  34 . In order to lock the closure lug in the position of closure of the case, the entering lug  16  is folded at right angles with respect to the opening/closing panel  14 .  
      The lug  16  is inserted between the front panel  5  and the lateral lugs  24  and  25 . This insertion is facilitated by rounded edges  21  of the entering lug  16 . The insertion of the entering lug  16  has the effect of making the rigid steps  28  and  29  enter the removals of material  18 . The rigidity and thickness of the sheet of rigid thick material confers on the steps  28 ,  29  and on the edges of the removals of material  18  sufficient rigidity and thickness to make it possible to obtain a snapping of the rigid steps  28 ,  29  into the removals of material  18 , so that the closure position of the case is firmly maintained and can be defeated only by manual manipulation of the closure lug.  
      In order to improve the snapping in, the steps  28 ,  29  can have a generally trapezoidal shape, the small base being produced on the edge close to the front panel  5 , and a dimension parallel to the folding lines  27 ,  26  allowing their insertion in the removals of material  18  without projection.  
      According to the embodiment depicted in the figures, the second opening is closed in a similar fashion by the second closure lug  22 .  
      The cuts  19  project substantially perpendicular to the opening/closing panel  14  when the entering lug  16  is folded at right angles with respect to this panel  14 , so that the folding line  17  is stiffened close to the removals of material  18  in order to prevent any tearing of this folding line  17 , which is subjected to stresses when the case  2  is opened or closed.