Abstract:
A method and device for closing a container provided with a neck including a pourer and a cap and an element carried by the pourer and a sealing membrane carried by the pourer so as to interposed between the element and the neck. The element is secured to the membrane by sealing after the device is applied to the neck and the element forced to urge the membrane against the neck.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a method and a device for closing a container provided with a neck and to a container equipped with such a device. 
   2. Description of the Related Art 
   It is known to make containers for liquid, such as milk bottles made of plastics material, for example high density polyethylene. In order to avoid drips of liquid during pouring from the neck of the container, it is known to equip this neck with a pourer forming a surface for flow of the liquid. 
   It is also known to close the neck of a bottle, equipped with a pourer or not, by means of a closure made of a sheet of aluminium, this closure generally being sealed on this neck. The removal of such a closure is generally not easy and a user not used to this type of closure does not understand intuitively. This results in false manipulations. In addition, even if he/she is used to this type of closure, it happens that the user does not manage to remove the closure completely, shreds of closure remaining in place on the edges of the neck or of the pourer, which creates an obstacle to the flow of the milk and renders the flow irregular. In addition, such shreds of closure hinder subsequent recycling and revalorisation of the bottle, which cannot be considered as a homogeneous object made of plastics material. 
   U.S. Pat. No. 4,815,618 teaches sticking a disc on a circular closure wedged, by its peripheral zone, between a neck and an annular part of the stopper. To remove the closure, it is necessary to break bridges connecting this disc to this annular part and to tear the closure whose peripheral edge remains jammed between the neck and the annular part. This requires a considerable effort likely to induce a rupture of the traction ring of the disc and/or to provoke projections. In addition, the bearing of the disc on the closure depends on the manufacturing tolerances of the stopper and of the neck of the container and it could not be excluded that the closure be incurved at the level of the disc, hence a risk of imperfect seal. 
   SUMMARY OF THE INVENTION 
   It is a more particular object of the invention to overcome these drawbacks by proposing a method for closing a container as described hereinabove which consists:
         when a stopper is fixed on the neck or the pourer of the container, in pressing towards the neck an element previously attached to the pourer, with interposed between this element and this neck, a tight sealed membrane closure of the neck; and   in securing this element to this membrane by sealing.       

   Thanks to the method of the invention, the positioning of the stopper induces a firm bearing or application of the afore-mentioned element on the membrane closure, which is used to advantage for securing them by sealing, this element then facilitating extraction of the membrane closure when the product contained in the container is to be used. 
   According to a first advantageous aspect of the invention, the method consists in sealing the element and the membrane closure firmly and in sealing the membrane closure and the neck in non-definitive manner. Thanks to this aspect of the invention, the membrane closure remains fast with the manoeuvring element when the latter is displaced with respect to the neck, which allows a complete tear of the membrane closure with respect to the neck. 
   The invention also relates to a closure device for carrying out the method as described hereinabove and, more specifically, to a closure device which comprises:
         an element adapted to be pressed towards the neck of the container due to the fixation of a stopper on the neck or on the pourer and   a membrane closure for this neck designed to be interposed between this element and this neck and to be sealed to this element and to this neck.       

   According to advantageous but non-obligatory aspects of the invention, the device incorporates one or more of the following characteristics:
         The afore-mentioned element is fast with a ring for gripping allowing it to be torn with respect to the neck.   The afore-mentioned element comprises a substantially planar surface, in the form of a ring or disc, for bearing against the membrane closure.   The membrane closure is adapted to be firmly sealed to the afore-mentioned element and to be removably sealed to the neck.   The membrane closure comprises a core made of a complex based on aluminium and coated, on a first face, with a peel-off varnish and, on a second face, with a film based on polyethylene.   The element is adapted to be maintained at a distance from the membrane closure by the pourer before fixation of the stopper on the pourer.   The element is formed in one piece with the pourer to which it is connected, before the fixation of the stopper, by at least one breakable bridge, this bridge making it possible to maintain the element at a distance from the membrane closure.   The stopper comprises a part adapted to exert on the afore-mentioned element an effort of thrust in the direction of the neck and of the membrane closure.   The pourer is equipped with a lip defining, with the afore-mentioned element, a chamber for pre-positioning of the membrane closure, this lip also participating in the tightness of the assembly between the pourer and the neck.       

   The invention also relates to a container for liquid, particularly a plastic bottle, equipped with a closure device as described hereinabove. Such a container is easier to manipulate than those of the state of the art, while its manufacture and cost price are economically satisfactory. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a closure device in accordance with its principle and of its method of implementation, given solely by way of example and made with reference to the accompanying drawings, in which: 
       FIG. 1  is an exploded view of a closure device and of the neck of a bottle according to the invention. 
       FIG. 2  is a view on a larger scale of detail II in FIG.  1 . 
       FIG. 3  is a half-section on a larger scale of the closure device of  FIG. 1  in the course of fixation on the corresponding bottle. 
       FIG. 4  is a section in perspective in the plane of section of  FIG. 3  while the closure device is fixed on the bottle, and 
       FIG. 5  is a section in the plane of  FIG. 3  while the membrane for closing the neck is in the course of withdrawal. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The bottle  1  shown in the Figures is a bottle intended to contain milk, made by blowing a high density polyethylene parison. The cost of such a bottle is attractive, while it performs its function efficiently. 
   The neck  2  of this bottle is substantially cylindrical and X 2 -X′ 2  denotes its axis of symmetry. This neck has a curved generatrix and it forms a slightly truncated part  21  of which the inner end constitutes the edge  22  of the neck  2 , part  21  extending opposite the edge  22  by a part  23  with curved generatrix outside which a thread  24  is formed. 
   The device of the invention also comprises a pourer  3  and a stopper or cap  4 , respectively, made of low density polyethylene and a high or medium density polyethylene. Other materials may, of course, be used for molding the elements  2 ,  3  and  4 , the material of the pourer advantageously remaining less rigid than those of the neck  2  and the stopper or cap  4 . 
   The pourer  3  is cylindrical and symmetrical about an axis X 3 -X′ 3  merged with axis X 2 -X′ 2  when the pourer  3  is screwed on neck thanks to an inner thread  34  provided to cooperate with the thread  24 . The pourer  3  comprises a part  31  with generatrix substantially rectilinear and parallel to axis X 3 -X′ 3  and of which the edge  32  opposite the body  11  of the bottle  1  is curved outwardly, with the result that it forms a surface  32   a  for flow of the milk towards the outside of the bottle  1 . 
   The pourer  3  also comprises a second part  33  with generatrix substantially parallel to axis X 3 -X′ 3 , parts  31  and  34  being joined by a truncated part  35  intended to abut against the outer surface  25   a  of a transition zone  25  between parts  21  and  23  of the neck  2 . 
   On its face  35   a  provided to come into contact with the surface  25   a , the part  35  is provided with ribs  35   b  intended to fit against complementary ribs  25   b  formed on the surface  25   a , these ribs  25   b  and  35   b  being oriented so that they oppose an unscrewing of the pourer  3  when the latter has been screwed on the neck  2 . 
   The part  35  is also bordered by a lip  35   c  provided to come into abutment against the surface  21   a , as shown in  FIG. 4 , with the result that the risks of flow of milk between the neck  2  and the pourer  3  are eliminated. 
   In the proximity of the surface  3 l a , the part  31  is connected to an annular seal element  36  by means of eight breakable bridges  37 . The seal element  36  forms, on its side oriented towards the lip  35   c , a substantially planar annular surface  36   a  perpendicular to axis X 3 -X′ 3 . The element  36  extends, opposite the surface the surface  36   a , by a clip  36   b  from which extends a ring  36   c  for gripping configured so that a user can easily insert a finger. 
   The assembly of the elements  31  to  37  constitutes the pourer  3  which is in one piece, these elements being integral with one another during molding thereof. 
   The stopper  4  is also substantially cylindrical and X 4 -X′ 4  denotes its axis of symmetry. The stopper  4  comprises a principal plate  41  in which is made an annular depression or hollow  42  which is bordered by a skirt  43  of which the inner surface is provided with a thread  44  adapted to cooperate with an outer thread  38  formed radially outside the part  33  of the pourer  3 . 
   The hollow  42  has a cross-section substantially in the form of a U and forms, seen from the inside of the stopper  4 , a convex part  45  of central radius R 45  with respect to the axis X 4 -X′ 4  substantially equal to the mean radius R 36  of the annular surface of the element  36 . 
   A membrane closure  5  is provided to be interposed between the neck  2  and the pourer  3  when the pourer is positioned on the neck. This membrane closure comprises a core  51  made of a sheet of a complex based on aluminium. This core is coated, on a first surface  51   a  intended to be in contact with the neck  2 , with a layer  52  of peel-off varnish and, on its surface  51   b  opposite the surface  51   a , with a film  53  of meltable polyethylene. 
   The radius R 5  of the membrane closure  5  is substantially equal to the maximum radius of the part  21  of the neck  2  and larger than the radii R 36  and R 45 . 
   The closure device formed by elements  3  to  5  is pre-assembled before it is fixed on the neck  2 . To that end, the membrane closure  5  is introduced in a pre-positioning chamber  39  of the pourer  3  which is defined between the surface  36   a  and the lip  35   c.    
   The lip  35   c  therefore has a dual function, namely, on the one hand, the maintenance of the membrane closure  5  in the chamber  39  before the device formed by elements  3  to  5  is positioned on the neck  2  and, on the other hand, the tightness of the assembly between the pourer  3  and the neck  2 . 
   After the membrane closure  5  has been positioned in the chamber  39 , the stopper  4  is screwed on the pourer  3 , by cooperation of the threads  44  and  38 , which has the effect of breaking the bridges  37  and of pushing the member  36  in the direction of the lip  35   c , as represented by arrow F 1  in  FIG. 3 , as the convex part  45  comes into abutment against the surface  36   d  of the element  36 . The lip  35   c  in that case serves as stop for the movement of the element  36  and of the membrane closure  5  opposite the edge  32 , the chamber  39  in that case being reduced between the surface  36   a  and the lip  35   c.    
   At the end of pre-assembling, the closure device is in the configuration of  FIG. 3  in which the element  36  is applied on the membrane closure  5  which is adjacent the lip  35   c.    
   Due to the screwing of the stopper  4  on the pourer  3 , a bead  45   a  formed on the outer surface of the part  45  is in abutment against the inner surface of the part  31  which it expands radially as represented by arrow F′ 1 , this inducing an additional locking of the stopper  4  on the pourer  3 . 
   The pourer  3  may then be screwed on the neck  2  by the cooperation of the threads  24  and  34 , which induces a firm abutment of the element  36  on the neck  2 , with the interposition of the membrane closure  5 , as shown in FIG.  4 . 
   The upper part of the bottle  1  and the elements  3  to  5  are then subjected to a heating by induction, the heat easily propagating in the core  51  which is metallic. Such induction heating has the effect of melting the film  53 , with the result that the element  36  is firmly sealed on the surface  51   b  of the membrane closure  5 . This induction heating also has the effect of melting the layer  52  of peel-off varnish, the membrane closure  5  also being sealed on the surface  21 . The bottle  1  is then hermetically closed. 
   The varnish constituting the layer  52  is chosen so that the fixation of the membrane closure  5  on the surface  21  is not definitive. This varnish may be of the type such as those used in the domain of the farm-produce industry for fixing covers on yoghurt pots. 
   When the milk contained in the bottle  1  is to be used, the user removes the stopper  4  by unscrewing it, which is natural. Just as naturally, he/she inserts his/her finger in the ring  36   c  and can pull thereon opposite the body  2  in an effort represented by arrow F 2  in  FIG. 5 , which has the effect of completely detaching the membrane closure  5  from the surface  21   a , as this membrane closure is firmly sealed on the surface  36   a  while it is removably sealed on the surface  21   a.    
   As a result, the assembly of the membrane closure  5  is effectively disconnected from the neck  2  without risk of tearing this closure, while the user does not have to search for a metallic tongue of difficult access in order to remove this closure. 
   The milk may thus flow over the surface  32   a  through the opening completely cleared by the membrane closure  5 . 
   The invention has been described with a screwed pourer and stopper, but it is applicable with a clip-on pourer and/or stopper or with a stopper forming part of a hinge assembly. 
   According to a variant of the invention (not shown), the membrane closure  5  may be coated with peel-off varnish and film of glue solely at its edge  54 , since the layers  52  and  53  are used only opposite the surfaces  21   a  and  36   a . In addition, methods of sealing other than those envisaged hereinbefore may be employed for connecting the membrane closure  5  with the element  36  and/or the neck  2 , particularly an adhesion of these elements or a superficial fusion of the element  36 . 
   The invention has been shown when used for a bottle of milk. However, it is applicable to any recipient provided with a neck.