Abstract:
Device for preparing a drink by extracting a measured quantity, for example of ground coffee, contained in a capsule ( 1 ) equipped with an extraction membrane ( 7 ), said device comprising a water inlet ( 5 ), a capsule holder ( 2 ), a capsule cage ( 3 ), clamping means and a set of spikes ( 6 ) for piercing said membrane ( 3 ); characterized in that the clamping means comprise a piston ( 4 ) mounted such that it can move with respect to the cage ( 3 ).

Description:
This application is the U.S. national phase of International Application No. PCT/IB2009/053983, filed 11 Sep. 2009, which designated the U.S. and claims priority to International Application No. PCT/IB2008/053717, filed 13 Sep. 2008, the entire contents of each of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention lies in the field of devices for preparing drinks by extracting a serving, for example of ground coffee, contained in a cartridge. 
     PRIOR ART 
     Devices that operate according to the abovementioned principle have existed for many decades. 
     U.S. Pat. Nos. 2,899,886, 2,968,560, 3,403,617 and 3,607,297 describe devices in which the cartridge is initially perforated at a number of locations and then pressurized water is passed through it. 
     the cartridge described in patent CH 605 293 or in patent EP 0 242 556 B1 comprises a membrane in its lower part. Pressurized water is initially introduced into the upper part of the cartridge, thereby causing the cartridge to swell, mainly at the membrane. Beyond a certain pressure, the membrane tears, and thus enables a mixture of water and coffee to flow out. 
     In the device presented in patent EP 0 512 470 B1, by bulging following the introduction of water into the cartridge, the membrane is squashed and perforated against a surface which comprises elements in relief. 
     Other devices that make use of a mode of operation identical or similar to those described above are presented in the following patents: EP 0 250 810 B1, EP 0 521 188 B1, EP 0 521 397 B1, EP 0 726 053 B1, EP 0 469 162 B1 and WO 92/07775. 
     Also known are devices where the mixture of water and coffee is first of all produced in the chamber containing the cartridge, but only starts to flow out when the pressure in the chamber containing the cartridge reaches a predefined minimum value. See in particular patent applications EP 0 726 053 A1, EP 0 622 039 A1 and EP 1 016 364 A2. 
     SUMMARY OF THE INVENTION 
     The present invention constitutes an improvement over the devices of the prior art. It consists in particular of a mechanism and a method for piercing the cartridge membrane in a progressive and efficient manner. 
     To this end, the invention relates firstly to a device for preparing a drink by extracting a serving, for example of ground coffee, contained in a cartridge equipped with an extraction membrane, said device including a water inlet, a cartridge holder, a cartridge cage, clamping means and a set of spikes intended to pierce said membrane, characterized in that the clamping means include a piston mounted in a movable manner with respect to the cage. 
     According to a first embodiment of the invention, the spikes are mounted in a movable manner in relation to the cartridge holder. 
     Advantageously, the device includes a mechanism for securing the movable spikes to the piston. 
     According to another embodiment of the invention, the cartridge cage comprises a cartridge-ejecting component. 
     In another variant of the invention, the ejecting component has no cartridge piercing elements. 
     The use of the device according to the invention includes the following successive steps:
         a cartridge is introduced into the cartridge cage;   the assembly formed by the cartridge holder, the cartridge cage and the clamping piston is lowered;   said assembly is clamped and the movable spikes are retracted into the inside of the cartridge holder; and   pressurized water is introduced into the cartridge, the piston is moved and the spikes are driven through the cartridge holder and the membrane.       

    
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
       The invention is described in more detail hereinbelow by means of examples illustrated in the following figures: 
         FIG. 1  describes an embodiment of a device according to the invention during the introduction of a cartridge. 
         FIG. 2  describes the device from  FIG. 1  at rest, after the cartridge holder and cartridge cage assembly has been closed. 
         FIG. 3  describes the device from  FIG. 1  after the cartridge holder and cartridge cage assembly has been clamped. 
         FIG. 4  illustrates the device from  FIG. 1  in the active position when water is passing through the device. 
     
    
    
     LIST OF REFERENCE NUMBERS IN THE FIGURES 
     
         
           1 . Cartridge 
           2 . Cartridge holder 
           3 . Cartridge cage 
           4 . Clamping piston 
           5 . Water inlet 
           6 . Spikes 
           7 . Extraction membrane 
           8 . Spike support 
           9 . Spike 
           10 . Expansion space 
           11 . Drink outlet 
           12 . Flange 
           13 . Lower end of the clamping piston 
           14 . Lower end of the cartridge cage 
           15 . Upper unit 
           16 . Upper spring 
           17 . Cartridge ejection part 
           18 . Ejection spring 
           19 . Lower unit 
           20 . Lower spring 
       
    
     The device illustrated in  FIGS. 1 to 4  includes a cartridge cage  3  comprising in its upper part a water inlet  5  which is connected to a water tank (not illustrated) and to a pump (not illustrated). The cartridge cage  3  is furthermore fastened to an upper unit  15  of the device. 
     The device also includes a clamping piston  4  mounted in a sliding manner with respect to the assembly formed by the cartridge cage  3  and the upper unit  15 , an upper spring  16  being located in the space formed between the inner wall of the upper unit  15  and the upper face of the clamping piston  4 . The inside of the cage  3  comprises a space intended to hold a cartridge  1  having a flexible membrane  7  in its lower part. The lower part  14  of the cage  3  is designed to come into contact with the flange  12  of the cartridge  1 . An ejection part  17  is located in the upper part of the cage  3  and mounted in a sliding manner with respect to the latter. The lower part of the ejection part  17  comprises spikes  9  intended to pierce the upper face of the cartridge  1 . An expansion space  10  is formed between the outer upper face of the cage  3  and the inner upper wall of the clamping piston  4 . The variation in the expansion space  10  will be discussed later in the text. 
     A cartridge holder  2  formed mainly of a perforated horizontal plate is located in the lower part of the device. A set of spikes  6  that are fixed to a support  8  located under the cartridge holder  2  is mounted in a movable manner in relation to the cartridge holder  2  through the perforations in the latter. 
     The device functions as follows: 
     A cartridge  1  is initially introduced into the cage  3  ( FIG. 1 ). 
     The assembly consisting of the upper unit  15 , the clamping piston  4  and the cage  3  is then lowered and reaches an intermediate position ( FIG. 2 ) which is characterized by contact between the lower end  13  of the clamping piston  4  and the spike support  8 . It should be noted that at this stage the spikes  6  emerge slightly from the cartridge holder  2  but do not pierce the membrane  7  because the latter has a certain flexibility and, moreover, pressurized water has not yet been introduced into the cartridge  1 . 
     The assembly consisting of the upper unit  15 , the clamping piston  4  and the cage  3  continues to be lowered until the device is located in a starting position ( FIG. 3 ). This latter movement has the effect of moving the spike support  8  and the spikes  6  downward, thereby causing the spikes  6  to retract into the cartridge holder  2 . At the same time, the lower part  14  of the cage  3  butts against the flange  12  of the cartridge  1 , thus ensuring optimal sealing between the cartridge  1  and the inside of the cage  3 . 
     It is noted, furthermore, that in the starting position the ejection part  17  has been retracted into a housing located in the upper part of the cage  3 , thereby having the effect of compressing an ejection spring  18  which is located between the ejection part  17  and the inner wall of the housing. 
     Pressurized water is then introduced into the device ( FIG. 4 ). By filling in particular the expansion space  10 , this has the effect of driving the clamping piston  4  upward. At the same time, the water enters the cartridge  1 . This results in an increase in pressure inside the latter and the membrane  7  stretches. 
     The upward movement of the clamping piston  4  also drives the spike support  8  upward. 
     The spikes  6  emerging through the cartridge holder  2  pierce the membrane  7 . The mixture of water with the contents of the cartridge  1  (for example coffee) thus flows out through the drink outlet orifice  11 . 
     Once the extraction operation has been carried out, the assembly consisting of the upper unit  15 , the clamping piston  4  and the cage  3  is raised. The ejection spring  18  relaxes, thereby driving the ejection part  17  downward. This movement has the effect of making it easier to eject the capsule  1  from the device. 
     It goes without saying that the invention is not limited to the device illustrated in  FIGS. 1 to 4 . It also covers any mechanism as described in the claims. 
     It will be noted that it is possible for the ejection component  17  to have no spikes. 
     More generally, it is possible for the device to have no spikes. In this case, the water is introduced into the cartridge by other means, for example via self-piercing reliefs.