Abstract:
A coffee machine brewing chamber for a coffee pad. Said brewing chamber comprises a top part that is provided with openings for the water which is delivered to the brewing chamber as well as a bottom part. The top part of the brewing chamber is embodied in a monolithic manner. The invention further relates to a coffee machine that is equipped with such a brewing chamber.

Description:
BACKGROUND 
     The invention relates to a brewing chamber of a coffee machine and a coffee machine. 
     Coffee machines operate according to different principles. The most common models are the so-called pressureless coffee machines such as are known, for example, from DE 296 10 393 U1. In these water flows from a storage container into an electrically heatable pipe. Particularly as a result of the evolution of steam in this pipe, heated water is then pushed through a riser to an outlet via which the heated water then drips into a coffee filter. The filter coffee, for example, can then flow from this coffee filter at atmospheric pressure into a pot. 
     In contrast, in espresso machines such as those disclosed in DE 197 01 033 A1, an elevated pressure prevails in the area of the coffee grounds. This is achieved by supplying water, for example, from a water container or another water supply to a pump which then supplies the water at high pressure via an electrically heatable area to a coffee grounds receiving device. This coffee grounds receiving device generally comprises a filter for receiving the coffee. In order to generate the high pressure in the area of the coffee grounds, during operation the coffee grounds receiving device is located in an area which is sealed towards the atmosphere, which is designated as a pressure chamber or brewing chamber. 
     In another type of coffee machine such as those described in WO 01/15582 or EP 1 050 258 A1, it is provided to first transfer the water for preparing the coffee from a water container into a heatable intermediate container. From this intermediate container the heated water is passed to a pump from which it is supplied at elevated pressure, for example 2 to 3 bar, to a coffee grounds receiving device. In this case, it is provided that the coffee is not introduced into the coffee grounds receiving device in loose form as coffee grounds but is inserted in a retainer in the form of a coffee pad, that is, in compacted form surrounded by filter paper. The retainer with a retainer cover via which water is supplied can form a sealed pressure chamber. At the same time, the retainer for the coffee pads is allocated a plurality of functions. Firstly, the retainer provides a sealing surface so that a pressure chamber can be formed. Moreover, the retainer has an outlet opening from which the coffee can emerge. Furthermore, the coffee pad should be mounted in the retainer in a manner such that flow through the coffee pad is not impeded. Such a coffee machine occupies an intermediate position between a conventional pressureless coffee machine and an espresso machine. 
     In the coffee machine disclosed in WO 01/15582 A1 the coffee pads are inserted in a lower portion of the brewing chamber and the upper portion of the brewing chamber can be folded onto the lower portion by the user by means of a hinge. An engaging connection between the two housing portions which are hinged relative to one another ensures sealing of the brewing chamber. 
     In the coffee machine known from EP 1 050 258 A1 the coffee pad is inserted in a pulled-out drawer and is then brought into the brewing position by pushing in the drawer. For sealing the brewing chamber, a brewing chamber upper portion is automatically moved over the coffee pad from above before the brewing process. After the brewing process, the coffee pads are automatically removed inside the coffee machine in a collecting container. Particularly as a result of the motor-driven components of the coffee machine, this is very complex and therefore expensive to produce. 
     SUMMARY 
     It is the object of the invention to improve a brewing chamber of a coffee machine. A further object of the invention is to provide a coffee machine with an improved brewing chamber. 
     This object is achieved by a brewing chamber of a coffee machine for a coffee pad, comprising a top part that is provided with openings for the water which is delivered to the brewing chamber and a bottom part, characterised in that the top part is embodied as monolithic. As a result of the monolithic design of this top part of the brewing chamber, production costs can be saved, especially if the top part of the brewing chamber has an outer seal. 
     According to one embodiment of the brewing chamber according to the invention, the top part has a centrally located elastic push-off element. This centrally located push-off element is appropriate since this arrangement corresponds to the symmetry of the preferably round coffee pad. Thus, the push-off force acts uniformly on the coffee pad and it is unlikely that this will adhere to the top part of the brewing chamber in any area. Furthermore, the central arrangement is useful since the openings for entry of water into the brewing chamber are preferably not centrally arranged but rather are located in a circular arrangement in the top part of the brewing chamber. 
     If the push-off element is substantially hemispherical in its stress-relieved state, as is provided according to one variant of the brewing chamber according to the invention, the push-off element can then be compressed similar to a rubber ball when pressing the coffee pad onto the top part of the brewing chamber and the coffee pad can be pushed off as a result of the transition to its stress-relieved state. 
     The push-off element can then be allocated properties which ensure secure push-off of the coffee pad from the top part of the brewing chamber in particular independently of the elastic properties and the other configuration of the top part of the brewing chamber if the push-off element is a star-shaped element having metal tongues as is provided according to a further embodiment of the brewing chamber according to the invention. According to a preferred embodiment of the brewing chamber according to the invention, the metal tongues are arranged between openings in the top part of the brewing chamber for entry of water so that they then impede the entry of water as little as possible. 
     According to a further preferred embodiment of the brewing chamber according to the invention, the top part has an elevated structure on the side facing the brewing chamber which structure can in particular comprise circularly arranged ribs provided with gaps. The elevated structure can in particular result in improved distribution of the brewing water and therefore improved usage of coffee. A further improvement in the distribution of the brewing water is obtained if the circularly arranged ribs are arranged concentrically and the gaps are arranged offset with respect to one another in the radial direction and/or the openings are arranged in the gaps. 
     According to a further variant of the brewing chamber according to the invention, the outer seal of the top part is executed as a tab-shaped circular lip and the top part comprises a plurality of supporting ribs for preventing any attachment of the tab-shaped lip to the top part. For improved assembly of the brewing chamber, it is provided according to a preferred variant of the brewing chamber according to the invention that the top part can be placed with the side facing away from the brewing chamber on the housing for the top part. Assembly is further simplified if that the side of the top part facing away from the brewing chamber comprises a projection whereby the top part can be engaged in the housing for the top part at lugs and in particular, if the projection is moulded on the top part. 
     The second object of the invention is achieved by a coffee machine fitted with a brewing chamber according to the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of a coffee machine according to the invention and exemplary embodiments of brewing chambers according to the invention are shown as examples in the following schematic figures. In the figures: 
         FIG. 1  is a perspective view of a coffee machine according to the invention, 
         FIG. 2  is a perspective view of a coffee machine according to the invention with a first embodiment of a top part of the brewing chamber according to the invention, 
         FIG. 3   a  is a plan view of the inside of the first embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 3   b  is a plan view of the outside of the first embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 3   c  is a sectional view along the intersecting plane identified as A in  FIG. 3   b  through the first embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 4  is a perspective view of a coffee machine according to the invention with a second embodiment of a top part of the brewing chamber according to the invention, 
         FIG. 5   a  is a plan view of the inside of the second embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 5   b  is a plan view of the outside of the second embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 5   c  is a sectional view along the intersecting plane identified as C in  FIG. 5   b  through the second embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 6  is a cutaway view of a brewing chamber with a third embodiment of a top part of the brewing chamber according to the invention, 
         FIG. 7   a  is a plan view of the inside of the third embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 7   b  is a perspective view of the third embodiment of the top part of the brewing chamber according to the invention, 
         FIG. 7   c  is a sectional view of the third embodiment of the top part of the brewing chamber according to the invention, 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a perspective view of a coffee machine  10  according to the invention. The coffee machine  10  comprises a flat front portion  12  and a columnar rear assembly  14 . Cups for removing coffee via an outlet  16  can be arranged on the front portion  12 . A water container  18  is inserted in the rear assembly  14 . Furthermore, a drawer  22  is provided for inserting coffee pads into the coffee machine  10 . 
       FIG. 2  shows a perspective view of the coffee machine  10  with a first embodiment of a top part  34  of the brewing chamber according to the invention. In this view the drawer  22  is shown removed from the coffee machine  10 . This exposes the view onto the slide-in area  24  for the drawer  22 . Clamps  26 ,  28  can be identified in this slide-in area, these being provided to grip around or grip underneath a coffee pad retainer  30  located in the drawer  22  in the inserted state of the drawer  22 . By actuating a lever  32  located on the upper side of the coffee machine  10 , the clamps  26 ,  28  can be displaced vertically so that the coffee pad retainer  30  acting as the bottom part of the brewing chamber can be pressed against the top part  34  of the brewing chamber. The top part  34  of the brewing chamber or its inside comprises an elastic material, in the present exemplary embodiment a silicone, so that a pressure chamber which serves as the brewing chamber is formed by pressing the coffee pad retainer  30  onto the edge zone of the top part  34 . Hot water enters into this brewing chamber under pressure from above through preferably a plurality of openings provided in the top part  34  of the brewing chamber. A substantially hemispherical push-off element  36  is provided at the centre of the top part  34  of the brewing chamber. This element is made of an elastic material like the remainder of the inside of the top part  34  and during the upward movement of the clamps  26 ,  28  this element is compressed by a coffee pad arranged in the coffee pad retainer  30  against the elastic force applied by the push-off element  36 . If the coffee pad is to be removed after the brewing process, the clamps  26 ,  28  are moved downwards and with them the coffee pad retainer  30 . In this case, as a result of its elasticity, the push-off element  36  can take on its original shape again whereby the coffee pad is pressed downwards. This prevents any attachment of the coffee pad on the top part  34  of the brewing chamber and it can easily be removed from the coffee machine  10  for disposal, together with the coffee pad retainer  30 , by pulling out the drawer  22 . 
       FIG. 3   a  shows a plan view of the inside of the top part  34  of the brewing chamber,  FIG. 3   b  shows a plan view of the top part  34  and  FIG. 3   c  shows a sectional view along the intersecting plane identified as A in  FIG. 3   b  through the top part  34 . The arrangement and construction of the push-off element  36  can be seen here.  FIG. 3   c  shows that the push-off element  36  is embodied as substantially hemispherical and is constructed in one piece with the remainder of the inside of the top part  34 . It can thus be compressed by the coffee pad and it prevents the coffee pad from attaching to the inside of the top part  34  by taking on its original shape on lowering of the coffee pad retainer  30 . 
       FIG. 4  shows a perspective view of the coffee machine  10  with a second embodiment of a top part  34 ′ according to the invention. This diagram is comparable to the diagram from  FIG. 2 . In contrast to the first embodiment of the top part  34  according to  FIG. 2 , in the second embodiment according to  FIG. 4  the push-off element is embodied as a star-shaped push-off element  38 . This star-shaped push-off element preferably consists of metal and as a result of the spring properties of the metal, it can act in a comparable manner to the push-off element  36  according to the first embodiment. 
       FIG. 5   a  shows a plan view of the inside of the top part  34 ′ of the brewing chamber,  FIG. 5   b  shows a plan view of the top part  34 ′ and  FIG. 5   c  shows a sectional view along the intersecting plane identified as C in  FIG. 5   b  through the top part  34 ′. In addition to the star-shaped push-off element  38 , openings  40  can be seen, these being distributed uniformly along a circumference of a circle on the top part  34 ′. During preparation of coffee hot water enters through these openings  40  into the brewing chamber. The star-shaped push-off element  38  is suitably equipped with five metal tongues with regard to the arrangement of the five openings  40 , these tongues being located between the openings  40 . In this way, the water can flow into the brewing chamber unhindered by the push-off element  38 . In the present case, the top part  34 ′ or its inside is preferably made of silicone to provide a sealing edge zone to form the brewing chamber together with the coffee pad retainer  30 . A bead  42  constructed in the elastic top part  34 ′ can also be slightly compressed during pressing of the coffee pad onto the push-off element  38  so that in any case, sufficient space for upward movement of the coffee pad is provided in order to reliably seal the brewing chamber. However, it is also feasible that in its non-deformed state, the push-off element  38  is at a distance from the bead  42 . In this case, the force required to strip the coffee pad can then be applied merely by the push-off element  38  at least towards the end of the downward movement of the tongues. The top part  34 ′ fitted with a star-shaped push-off element  38  can also be implemented without a bead  42 . 
       FIG. 6  shows another brewing chamber  60  according to the invention with a third embodiment of a top part  34 ″,  FIG. 7   a  shows a plan view of the inside of the top part  34 ″,  FIG. 7   b  shows a perspective view of the top part  34 ″ and  FIG. 7   c  shows a sectional view of the top part  34 ″. 
       FIG. 6  shows part of the water supply  61  to the brewing chamber  60 , a housing  62  for receiving the top part  34 ″ and the coffee pad retainer  30 . The top part  34 ″ is executed as circular and has a moulded-on projection  63  on the side facing away from the brewing chamber  60  whereby the top part  34 ″ is engaged in the housing  62  at moulded lugs  64  to receive the top part  34 ″. 
     As can be seen in particular from  FIG. 7   a  to  7   c , the top part  34 ″ has an elevated structure on the side facing the brewing chamber  60  which in the present exemplary embodiment comprises circularly and concentrically arranged ribs  65  having gaps  66 . In the present exemplary embodiment the gaps  66  are radially offset with respect to one another. In order that water coming from the water supply  61  can enter into the brewing chamber  60 , the top part  34 ″ is also provided with holes  67  which are arranged in some of the gaps  66 . 
     In the present exemplary embodiment, the top part  34 ″ is also made of silicone or rubber in order to thus provide a sealed edge zone to form the brewing chamber  60  together with the coffee pad retainer  30 . In the present exemplary embodiment the sealing edge zone of the top part  34 ″ is embodied as circular and comprises a tab-shaped lip-like outer sealing ring  68 . In order to prevent attachment of the sealing ring  68  to the surface of the top part  34 ″, in the present exemplary embodiment the top part  34 ″ further comprises a plurality of supporting ribs  69 .