Abstract:
The invention relates to a capsule for preparing a drink, for example coffee, comprising a hollow element ( 1,1   a,   1   b ) for containing a dose, for example of ground coffee. Said hollow element ( 1,1   a,   1   b ) has a lateral wall ( 2, 2   a,    2   b ), an upper face ( 3 ) and a lower face ( 4 ), the lower part of said lateral wall ( 2, 2   a,    2   b ) extending in such a way as to create a rim ( 6, 3   a,    3   b ) oriented along a plane cutting the lateral wall ( 2, 2   a,    2   b ). The invention is characterised in that the thickness of the upper face ( 3 ) and/or the lateral wall ( 2, 2   a,    2   b ) and/or the rim ( 6, 3   a,    3   b ) is variable.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is situated in the field of the preparation of drinks, for example based on coffee, by extraction of a concentrated dose, for example of ground coffee, contained in a capsule. It relates more particularly to the doses used for this purpose and to the devices using such doses. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    Capsules and machines operating according to the aforementioned principle have existed for many decades. 
         [0003]    Patents U.S. Pat. No. 2,899,886, U.S. Pat. No. 2,968,560, U.S. Pat. No. 3.403.617 and U.S. Pat. No. 3,607,297 describe devices in which the capsule is initially perforated in several locations then passed through by pressurized water. 
         [0004]    The capsule described in patent CH 605 293 or in patent EP 0 242 556 B1 comprises a membrane in its bottom portion. Pressurized water is initially inserted into the top portion of the capsule, which causes the capsule to swell, mainly at the membrane. From a certain pressure, the membrane tears, thereby allowing a water-coffee mixture to flow. 
         [0005]    Other capsules furnished with a membrane are described in the following patent documents: EP 0 468 079 A, EP 0 806 373 A, EP 0 554 469 A. 
         [0006]    Although the majority of the hot water inserted under pressure enters and passes through the capsule, another portion flows outside the latter, along the outer face of the side wall. In principle, these leakages should not flow beyond the base of the side wall because, at this location, the capsule cage is in contact with the rim. 
         [0007]    Unfortunately this is not the case with the capsules and the capsule cages of the prior art. Liquid can therefore flow outside the machine and/or mix with the liquid that has passed inside the capsule. In the latter situation, the quality of the coffee is diminished. 
         [0008]    There is therefore a need to reduce, or even eliminate, the leakages of liquid that flows along the outer face of the side wall of the capsule. 
       SUMMARY OF THE INVENTION 
       [0009]    One of the objectives of the present invention lies in improving the flow of the liquid through the capsule. The object of the invention is to prevent liquid flowing along the side wall of the capsule. 
         [0010]    By “extra thickness”, it should be understood that the element concerned, namely the top face, the side wall or rim, comprises a portion the thickness of which is greater than the thickness that forms the other portion of the element concerned. It should however be noted that this increased thickness does not result from a fold (double layer) of the side wall. 
         [0011]    The material of the side wall and the rim is preferably elastic. 
         [0012]    Advantageously, it is a biodegradable material. 
         [0013]    Several equivalent ways of forming a rim having a greater thickness or an extra thickness are possible and are illustrated as exemplary embodiments in the present application. Naturally, they are examples that must not be considered limiting and variants are possible in the context of the present application. 
         [0014]    Similarly, by “lesser thickness”, it should be understood that the element concerned, namely the top face, the side wall or rim, comprises a portion the thickness of which is smaller than the thickness that constitutes the other portion of the element concerned. 
         [0015]    Most frequently, the presence of an extra thickness is designed to improve the seal while the presence of a lesser thickness is designed to weaken the element concerned, for example in order to make it easier to pierce. 
         [0016]    According to one variant of the invention, the seal between the rim and the bottom portion of the capsule cage is improved by virtue of the softening of the material that forms the capsule. Specifically, when water flows over the outer face of the wall of the capsule and contacts the rim, the latter softens. The capsule cage may therefore sink more deeply into the thickness of the rim. The seal at this location is therefore improved. 
         [0017]    Any material that behaves as indicated above, that is to say softens, can be used in the context of the present invention. 
         [0018]    According to another variant of the invention, the capsule comprises a gutter which is designed to be deformed at least partially by the cage when the device is closed. 
         [0019]    It should however be noted that the invention is not limited to the aforementioned fields of use. One or more extra thicknesses, respectively one or more lesser thicknesses, may be used for other purposes. The presence of extra thicknesses placed in the bottom portion of the side wall may be used to make it easier to center the capsule in the capsule cage. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         [0020]    1 st  Series of Examples 
           [0021]      FIG. 1  shows a first embodiment of a device and of a capsule according to the invention. 
           [0022]      FIG. 2  shows a section of the object of  FIG. 1  in the open position. 
           [0023]      FIG. 3  shows a section of the object of  FIG. 1  in the closed position. 
           [0024]      FIG. 4  illustrates an enlargement of the zone of contact between the rim of the capsule and the device of  FIG. 1 . 
           [0025]      FIG. 5  shows a second embodiment of a device and of a capsule according to the invention. 
           [0026]      FIG. 6  shows a section of the object of  FIG. 5  in the open position. 
           [0027]      FIG. 7  shows a section of the object of  FIG. 5  in the closed position. 
           [0028]      FIG. 8  illustrates an enlargement of the zone of contact between the rim of the capsule and the device of  FIG. 5 . 
           [0029]      FIG. 9  illustrates an embodiment of a capsule holder with perforation elements in the retracted position. 
           [0030]      FIG. 10  the capsule holder of  FIG. 9  with the perforation elements in the active position. 
           [0031]      FIG. 11  illustrates an example of a capsule comprising elastic extra thicknesses on its side face. The extra thicknesses form an integral portion of the side wall. They are therefore formed of the same material. 
           [0032]      FIGS. 12 and 13  illustrate another form of extra thickness on the side wall, but spiral-shaped. 
           [0033]      FIGS. 14 to 38  illustrate particular embodiments of the invention. 
       
    
    
       [0034]    Reference Numbers used in  FIGS. 1 to 38 : 
         [0035]      1 . Hollow element 
         [0036]      2 . Side wall 
         [0037]      3 . Top face 
         [0038]      4 . Bottom face 
         [0039]      5 . Extraction membrane 
         [0040]      6 . Rim 
         [0041]      7 . Capsule holder 
         [0042]      8 . Capsule housing 
         [0043]      9 . Liquid outlet 
         [0044]      10 . Bottom portion of the capsule housing 
         [0045]      11 . Membrane perforation element 
         [0046]      12 . Plate 
         [0047]      13 . Hole 
         [0048]      14 . Side extra thickness 
         [0049]    Preferably, the top face of the rim  6  forms an angle of less than 90° with the side wall, which has the effect of making it easier for the capsule housing to penetrate the rim  6 . 
         [0050]    The plate illustrated in  FIGS. 9 and 10  is made movable while the perforation elements  11  are fixed. The movement of the plate occurs starting from a certain pressure that prevails in the capsule. Beneath this threshold pressure, the plate is held by an element, for example a calibrated leaf spring. 
         [0051]    The bottom edge of the capsule cage illustrated in  FIGS. 16 and 17  comprises a crenelated relief the object of which is to increase the area of contact with the rim of the capsule and to make it easier for the cage to penetrate the rim. The seal at this level is therefore improved. 
         [0052]      FIGS. 19 to 32  represent various embodiments of extra thicknesses and of lesser thicknesses that are placed on the rim. 
         [0053]    Note in particular certain examples (see  FIGS. 23 ,  25 ,  29 ,  30 ) which have recesses on the side of the bottom face of the rim. The latter may for example be used as housings for the insertion of elements that form the base of the capsule such as rings or rigid disks. The making of hollows on the rim may also be used to increase its flexibility. 
         [0054]    2 nd  Series of Examples 
         [0055]      FIG. 1   a  represents a capsule  1   a  according to a first embodiment of the invention after closure of the cage  4   a , but prior to the entry of hot water. 
         [0056]      FIG. 2   a  illustrates the entry of hot water  7   a , mainly into the capsule  1   a , but also into the space  6   a  that is situated between the outer face of the side wall  2   a  of the capsule and the inner face of the cage  4   a.    
         [0057]      FIG. 3   a  illustrates the positioning of the cage  4   a  relative to the rim, after the latter has softened. 
         [0058]      FIGS. 4   a  to  6   a  illustrate a second embodiment of the invention. 
         [0059]    List of Reference Numbers used in  FIGS. 1   a  to  6   a:    
         [0060]      1   a . Capsule 
         [0061]      2   a . Side wall 
         [0062]      3   a . Rim 
         [0063]      4   a . Cage 
         [0064]      5   a . Bottom portion of cage 
         [0065]      6   a . Space between the capsule and the cage 
         [0066]      7   a . Water 
         [0067]      8   a . Chicane 
         [0068]      9   a . Inclined wall portion 
         [0069]    According to the invention, the capsule la for the preparation of a drink, for example coffee, comprises a hollow element designed to contain a dose, for example of ground coffee. The hollow element comprises a side wall  2   a , a top face, a bottom face with an extraction membrane and a rim  3   a ; said side wall  2   a  extending in its bottom portion so as to form said rim  3   a , the latter being oriented on a plane that intersects said side wall  2   a . According to the invention, the rim  3   a  is formed at least partially of a material that softens when it is placed in contact with a liquid. 
         [0070]    Preferably, the softening temperature of said material is higher than the ambient temperature. 
         [0071]    The capsule illustrated in  FIGS. 4   a  to  6   a  differs from the capsule of  FIGS. 1   a  to  3   a  only in that the base of the side wall  2   a  forms an inclined annular zone  9   a  and that a bulge  8   a  is placed on the latter. 
         [0072]    The bulge  8   a  is of a size to reduce (and not remove) the cross section of the passageway through which the liquid flows. The bulge  8   a  therefore does not constitute a seal but rather a chicane which has the effect of slowing the quantity of liquid that comes into contact with the rim  3   a.    
         [0073]    Specifically it has been found that, surprisingly, the slowing of the quantity of liquid contacting the rim  3   a  improves the seal between the capsule cage  4   a  and the rim  3   a.    
         [0074]    3 rd  Series of Examples 
         [0075]      FIG. 1   b  represents a partial view in section of a capsule according to the invention in the cage in a first position; 
         [0076]      FIG. 2   b  illustrates a detail of  FIG. 1   b;    
         [0077]      FIG. 3   b  illustrates a partial view in section of the capsule of  FIGS. 1   b  and  2   b  in a second position; 
         [0078]      FIG. 4   b  illustrates a detail of  FIG. 3   b . 
         [0079]    According to the invention and as illustrated in the figures, the capsule  1   b  comprises a side wall  2   b  and a rim  3   b . The capsule  1   b  is placed on a support  6   b  and is surrounded by a cage  5   b.    
         [0080]    A gutter  4   b  is placed in the bottom portion of the side wall  2   b . The gutter  4   b  is formed notably of a ridge  6   b  that is oriented so as to face the cage portion  5   b  designed to come into contact with it. 
         [0081]    In  FIGS. 1   b  and  2   b , the cage is in the open position. 
         [0082]      FIG. 2   b  illustrates an enlargement of  FIG. 1   b  above. 
         [0083]      FIGS. 3   b  and  4   b  illustrate the effect of the cage  5   b  on the gutter  4   b  when the capsule  1   b  is clamped in its cage  5   b.    
         [0084]      FIG. 4   b  illustrates an enlargement of  FIG. 3   b.    
         [0085]    List of reference numbers used in  FIGS. 1   b  to  4   b:    
         [0086]      1   b . Capsule 
         [0087]      2   b . Side wall 
         [0088]      3   b . Rim 
         [0089]      4   b . Gutter 
         [0090]      5   b . Cage 
         [0091]      6   b . Support 
         [0092]    As can be seen in  FIGS. 3   b  and  4   b , the cage  5   b  sinks into the gutter  4   b  because the latter has previously been softened following the arrival of liquid in the space that is situated between the cage  5   b  and the side wall  2   b.    
         [0093]    The presence of the gutter  4   b  has the effect of slowing the flow rate of the hot water, or of containing it, while the block of material used as a base for the gutter  4   b  softens. The sinking of the cage  5   b  into the bottom portion of the side wall  2   b  is therefore increased which has the effect of improving the seal at this location, the liquid not being able to flow beyond the gutter  4   b.    
         [0094]    The present invention is not limited to the examples and modes of execution described purely as an illustration. Variations are possible in the context of the claimed protection, notably by making use of equivalent means. This relates particularly to the shape of the extra thicknesses, of the lesser thicknesses and of the gutter. It will be noted finally that it is not necessary to furnish the base of the capsule with an inclined wall portion.