Abstract:
A container suitable to house rolls of material in thin foils, the container being produced in cardboard and having an edge or corner thereof along which there extends a continuous series of teeth projecting towards the outside of the box and through which it is possible to tear and remove portions of foil material from the roll. The teeth of the toothed edge are reinforced through an adhesive strip of plastic material with respect to the remaining part of the cardboard, to withstand, without being permanently deformed, the tearing of a large number of portions of foil material.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a container made of cardboard or similar material and suitable to house rolls of thin and tearable foil material, the container being in the shape of an elongated parallelepiped and being provided with a series of teeth punched in the cardboard and with the cusps thereof projecting outward, these teeth being suitable to cut the foil material to allow portions thereof to be torn and removed from the respective roll housed in the container. The invention also relates to the method for the production of the aforesaid container. 
         [0003]    2. Description of the Related Art 
         [0004]    The patents U.S. Pat. No. 4,967,911 and corresponding patent EP 0 369 346 B describe containers of the aforesaid type, produced entirely in a single piece of punched, creased and folded cardboard, suitable to house a roll of tearable foil or thin film material, such as aluminium, plastic material (e.g. PET or PVC), baking paper or the like. These containers have a cutting edge produced along a longitudinal corner or edge of the box, between the bottom wall and the front wall thereof. These containers have the drawback that their teeth (designed to cut the foil material and cause tearing thereof when the foil is unwound from its roll and is stretched and pulled on the teeth of the relative container) are only present along a portion of the length of the cutting edge of the box (thus making the operation to tear off the desired portion of foil material very difficult and irregular) and that said teeth extend freely for their entire length outside the edge or corner of the box, so that the teeth are freely flexible and deform easily and rapidly and can therefore no longer perform the function for which they were designed. 
         [0005]    The patent U.S. Pat. No. 3,777,957 describes an embodiment of a container intended to overcome the aforesaid drawbacks by providing that the teeth designed to cause tearing of the foil material are produced on a toothed and sharp blade (called cutter blade) which is affixed to a wall of the container in such a manner that the toothed and cutting edge of the blade projects outside the free edge of the wall of the container to which it is affixed. An embodiment of this kind presents unacceptable drawbacks, such as a high cost, difficulty in producing the blade with the cutting teeth, the necessity and the difficulty of fixing this blade to the respective cardboard wall of the container, the fact that the teeth of the blade can scratch the surfaces of tables or furniture on which the containers are placed, or can wound the hands of persons using these boxes, besides the fact that the aforesaid blades must be removed from the containers before disposal thereof when the roll of foil material is finished. 
         [0006]    The patent GB 1483620 describes a container the object of which is to overcome the aforesaid drawbacks by producing the cutting edge of the container using a strip of abrasive particles which is affixed to the surface of the cardboard by means of an adhesive: the production of this container is somewhat complex and costly and, in fact, it has not been a commercial success. 
         [0007]    The patent application GB 2128590A describes a container made of cardboard and having cutting teeth (produced in the same sheet of cardboard) to which—after the cardboard has been punched, creased and folded to form the container—a resin is applied and subsequently polymerized to give a hardened edge with sharp teeth: it is evident that this construction technique is not industrially feasible. 
         [0008]    Finally, the patent DE 2930725A1 describes a container housing a roll as defined above, the container having a lid from which there extends a wall which is positioned over and outside the front wall of the container: the wall which is part of the lid has a free edge shaped to present a continuous series of teeth or the like which are reinforced by an adhesive tape affixed to this wall and also provided with teeth, placed over (and produced simultaneously to) the teeth present on the free edge of the lid. The teeth are thus strengthened, but, being bent toward the inside of the container, when the foil material is cut, the entire wall projecting from the lid is consequently lifted outward forming an arch (making it impossible to use the container described in the German patent) when the foil is pulled out of the box, passing under the wall projecting from the lid and deforming this wall. 
       SUMMARY OF THE INVENTION 
       [0009]    The main object of the present invention is to produce a container of the aforesaid type, which is easy and inexpensive to produce from a sheet of cardboard (or similar material) punched, creased and folded, having at least one edge or corner thereof along which there are provided teeth for cutting or tearing the foil material, where these teeth have high resistance to deformation. 
         [0010]    Another object is that of producing a container that is not dangerous for the user and which, after use, can be disposed of as is, without having to remove constituent parts thereof. 
         [0011]    These and other objects are achieved with a container for a roll of thin foil material, having a toothing for tearing portions of said foil material from the roll, comprising a bottom wall, a front wall, a rear wall, a top wall and an end wall which can be placed over said front wall, said walls being mutually consecutive and separated from one another by mutually parallel fold lines about which the walls are folded to form a parallelepiped housing for said roll, there being produced in at least one of said walls cuts that delimit said toothing, the cusps of the teeth being engageable by the foil of material unwound from said roll and pulled on these teeth to cause tearing of a portion thereof, wherein the teeth of the toothing produced on the portion of end wall are separated from one another by rectilinear cuts to form a continuous series of cuts and teeth, in that the teeth produced in the front wall are separated from one another by fold lines, in that in the assembled box the teeth are positioned and in contact with the fold lines that separate the teeth from one another while the teeth are positioned and in contact with the adjacent edge of the cuts that separate the teeth from one another. 
         [0012]    Preferably, said end wall is divided into two distinct portions by continuous knurling, and the portion of end wall is glued to the outer surface of the front wall of the box. 
         [0013]    Once again preferably, a strip of plastic material, in which cuts are produced and also delimiting a toothing placed over and coincident with the toothing produced on the cardboard, is affixed to at least one surface of the wall on which said cuts are produced, over these cuts. 
         [0014]    The invention also relates to a method for producing a container for rolls of thin foil material, having a toothed edge for tearing portions of said foil material from the respective roll, characterized in that a strip of plastic material is affixed to at least one surface of a sheet of cardboard or the like, the sheet of cardboard or the like is then punched and creased to provide a blank which is folded and assembled according to conventional prior art methods, characterized in that in the punching step, in the area in which said strip of plastic material is affixed to the surface of the cardboard foil, cuts are made which cut both the strip of plastic material and the sheet of cardboard and which define a series of teeth whose cusps form said toothing in the container assembled and obtained by folding the sheet of cardboard about the crease lines produced thereon. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    To facilitate comprehension of the features of the container according to the invention and the manner of achieving it, a non-limiting embodiment shall now be described with reference to the accompanying drawings wherein: 
           [0016]      FIGS. 1 to 4  show the various subsequent operating steps to obtain a cardboard blank, the cardboard being shown in a plan view, flat and extended; 
           [0017]      FIGS. 5 and 6  show two subsequent steps of folding the previously punched and creased cardboard; 
           [0018]      FIG. 7  is a perspective and partial view of the front side of the finished container; 
           [0019]      FIGS. 8 and 9  are partial sections of the container, according to the lines  8 - 8  and respectively  9 - 9  of  FIG. 7 ; and 
           [0020]      FIG. 10  is a perspective and partial view of the container, shown during the operation to tear a portion of foil material from a roll of this material housed in the container. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    To describe the features of the container of the invention, we shall firstly describe the method for the production thereof. 
         [0022]    Two pieces of plastic strip  2 , e.g. PET or PVC, with a thickness of  125  microns, are affixed (for example glued using vinyl glue) to a sheet of cardboard  1  (or other material suitable to form the container) ( FIG. 1 ). Subsequently, with the use of an automatic machine of well-known type, a punching and creasing operation is performed on the cardboard  1 , through which the blank, represented in a plan view and in enlarged scale in  FIG. 3 , is separated from the remaining part of the cardboard. 
         [0023]    It can already be noted that this blank is provided with crease or fold lines (from 3 to 6) which separate from one another five different and consecutive portions of cardboard designed to form—in the finished container—a bottom wall  7 , a front wall  8 , a rear wall  9 , a top wall  10  and a front wall which is divided into two parts  11  and  11 A by a predetermined and facilitated tearing line or knurling  12 : a shaped cut is produced in the part  11 A, which delimits therein an appendix  13  integral with the part  11  and suitable to be inserted (as will be explained hereunder) in a shaped opening  14  produced in the wall  8 . 
         [0024]    The fold or crease line  3  is composed of a discontinuous series of short segments of crease (mutually connecting the walls  7  and  8 ) separated from one another by a series of saw tooth cuts  15  produced through punching in the wall  8 . 
         [0025]    Similarly, a series of short rectilinear cuts  16 , separated from one another by a group of tooth cuts  17  forming part of a series of saw tooth cuts  17 , are produced in the part  11 A of the front wall. 
         [0026]    From the figures it can also be noted that tabs (not numbered for simplicity) project from the ends of all the aforesaid walls, these tabs being designed to close the two ends of the container that is obtained at the end of all the assembly operations described hereunder. 
         [0027]    The structure of the piece of cardboard blank described above is already known and is similar to the one illustrated in the prior art patents EP0369346B and U.S. Pat. No. 4,967,911 mentioned in the introduction of the present description. 
         [0028]    An advantageous feature of the present invention consists in the presence of strips of plastic material  2  glued onto one (or if necessary onto both of the opposite surfaces of the sheet of cardboard  1 ) and, simultaneously, in the fact that the saw tooth cuts  15  and  17  (and also the series of short cuts  16 ) are obtained by simultaneous punching both on the sheet of cardboard  1  and on the pieces of strip  2  affixed thereto: it has been found that, in this manner, the teeth  15 ,  17  (which have the function of causing tearing of the thin foil of web material unwound from its roll enclosed in the container) have a much greater resistance to deformation thereof than they would have if they were not covered, on one or both the faces thereof, by the protective layer of the plastic strip. 
         [0029]    It is evident that the plastic strip  2  is provided in those areas of the cardboard provided with the toothings having the function of causing tearing of the thin foil material which the container is designed to contain. 
         [0030]    We shall now return to consider  FIG. 2  which shows the cardboard on which, after affixing of the pieces of strip  2 , the punching and creasing operations have been performed, already described and at the end of which the blank shown in  FIG. 3  is separated from the cardboard. It is important to note that, as a result of the fact that the short rectilinear cuts  16  and the saw tooth cuts  17  produced (during the punching operation of the cardboard) in the part  11 A of the front wall form a single continuous longitudinal cut, when the blank of  FIG. 3  detaches from the punched cardboard a portion of the strip  2  remains attached to the cardboard frame  1  (which is discarded), separating from the other portion of strip which remains affixed to the part  11 A of the front wall of the container: the cuts  16  and the teeth  17  thus form a continuous series delimiting the free edge of the part  11 A designed to form part of the front wall of the container. 
         [0031]    To form the container starting from the blank of  FIG. 3 , this blank is turned over, so that it is as shown in  FIG. 4 . At this point the cardboard is folded about the fold line  4  ( FIG. 5 ), placing the wall  7  over the wall  9  and the wall  8  over the wall  10 , then applying a layer of glue  20  along the free longitudinal edge of the portion of wall  11 A ( FIG. 5 ); the cardboard is then folded over itself along the fold line  6 , placing the portion of wall  11  over the wall  10  and affixing (through the layer of glue  20 ) the portion of wall  11 A to the wall  8  ( FIG. 6 ). 
         [0032]    As can be noted in  FIG. 6 , the teeth  17  of the part  11 A of the front wall of the cardboard are placed over the fold lines  3  of the wall  8 , the cusps or tips of these teeth  17  projecting slightly beyond the respective fold lines  3 , while the teeth  15  are placed over the cuts  16 , also projecting slightly over and beyond these cuts. 
         [0033]    At this point the operations for industrial production of the container are terminated and, by exerting a force for mutual approach (in the direction shown schematically by the arrows A-A in  FIG. 6 ), the container assumes a square shape which delimits a trapezoidal cavity defined by a bottom wall  7 , by a front wall  8 , by a rear wall  9  and by a top wall  10  from which an end wall  11 ,  11 A extends, placed over the front wall  8  and divided into the two portions  11 ,  11 A by the transverse and tearable knurling  12 . 
         [0034]    A roll  30  of thin foil material  31  ( FIG. 10 ), a portion of which can be unwound and torn from the roll  30 , can be inserted in the assembled container described above (through the ends of the container, still open). 
         [0035]    As in the closed container containing the roll  30  the portion of wall  11 ,  11 A is glued to the outer surface of the wall  8 , to open this container it is necessary and sufficient to break the wall  11 ,  11 A along the tearing line  12 : in this manner the portion of wall  11 A will remain fixed and glued to the wall  8 , while the portion of wall  11  can be lifted upward (together with the wall  10 ), rotating about the fold line  5 : it will thus be possible to grasp the free edge of the thin foil  31  and pulling it out of the container—to unwind from the roll  30  a portion of the desired length which can then be easily torn (and removed) by pressing it against the teeth  15  and  17  delimiting the lower front corner of the container ( FIGS. 7 and 10 ). 
         [0036]    For greater clarity,  FIGS. 8 and 9  represent, in enlarged scale, two (partial) sections of the container, taken according to the lines  8 - 8  and  9 - 9  of  FIG. 7 . 
         [0037]    From these  FIGS. 7 ,  8  and  9 , the most important feature of the container described above can easily be perceived. It is seen that a substantial part of the teeth  17  (projecting from the portion of wall  11 A which is glued to the wall  8 , is resting on and held pressed on the this wall  8 , while only a small portion (the cusps) of these teeth  17  project beyond the lower surface of the wall  7 ; and that a substantial part of the teeth  15  (projecting from the wall  7 ) is resting on and supported by the free edges of the cuts  16 , while only a small portion (the cusps) of these teeth projects beyond the outer surface of the part of wall  11 A. Therefore, along the entire front and lower corner of the container there is provided a continuous cutting edge formed by the series of teeth  15  and  17 , which are practically non-deformable under the thrust of the foil  31  which is torn from the roll  30 . 
         [0038]    It is evident that the structure of the container for the roll of thin foil material can differ from the one represented in the accompanying drawings. This structure can be of any known shape for the object at which the present invention is aimed; for example, the container can have the shape of any one of the containers described in the prior art patents already cited or have the toothed edge produced solely on the free edge of the wall  8  or on the free edge of the portion of wall  11 A, or yet another solution. 
         [0039]    It is advantageous that the teeth designed to cut the thin foil material extracted from the container are protected and covered, a least on one surface thereof, by a layer or strip of plastic material or the like (e.g. a thin foil of metal, such as a foil of aluminium) in which the toothing for tearing is produced by punching simultaneously to the toothing produced in the sheet of cardboard or the like.