Coffee maker

[0001] The present invention refers to a coffee maker comprising at least one coffee bean container adapted to receive whole coffee beans to be ground, at least one coffee grinder assembly adapted to grind the whole coffee beans contained in the coffee bean container, and a brewing module having a brewing chamber adapted to receive the ground coffee from the coffee grinder assembly and to extract the ground coffee by means of hot brewing water.

[0002] Coffee makers of the kind referred to herein are predominantly used in household and serve for fully automatically preparing a fresh coffee beverage. In order to prepare a coffee beverage, a defined amount of coffee beans is discharged from the coffee bean container into the coffee grinder assembly and subsequently ground therein. The ground beans, i.e. the coffee powder, is fed to the brewing chamber where it is compressed. Hot, pressurized brewing water is fed into the brewing chamber to extract the coffee powder contained therein.

[0003] U.S. Pat. No. 5,193,438 discloses a coffee maker comprising two bean containers and two coffee grinder assemblies. The axes of rotation of the two coffee grinder assemblies extend in horizontal direction. The outlets of the two coffee grinder assemblies are connected to a vertical stub having a common outlet opening. The vertical stub is should be easily removable for the purpose of easy cleaning. A rotating support member is located below the outlet opening of the stub, provided with two receiving chambers for ground coffee located diametrically opposite to each other. The support member is rotatable in such a way that the respective receiving chamber can be brought from a fill position into a brewing position. In the brewing position, the coffee powder received in the respective chamber can be used for brewing a coffee beverage. The provision of two independent coffee bean containers and of two grinding assemblies should make it possible to prepare two different coffee beverages.

[0004] The document EP-A-0,472,272 discloses a fully automatic coffee machine comprising, besides the usual components, a milk froth unit as well as two coffee bean containers with two associated grinder assemblies. While one of the two coffee bean containers is adapted to receive conventional coffee beans, the other coffee bean container is adapted to receive decaffeinated coffee beans. Below the two grinding assemblies, a brewing unit is located, directly connected to one of the coffee bean containers by means of a feed channel. The other coffee bean container can be connected to the brewing unit by means of an electro-mechanically operated feed channel. By this design, it is allowed for gathering and grinding coffee beans selectively from the one or the other coffee bean container, with the result that the brewing unit is fed either with conventional or with decaffeinated coffee beans to freshly prepare an according coffee beverage.

[0005] The document EP-A-766,943 discloses a coffee maker having an electronic control unit and also comprising two coffee bean containers and two associated grinding assemblies. The electronic control unit is adapted to operate the respective grinder assembly. Thereby, the control unit shall, amongst else, consider the wearing down of the respective grinder assembly such that a constant quality of the prepared coffee beverage is assured. Contrary to the two previously discussed prior art coffee makers, this coffee maker comprises two separate brewing units in the form of manual filter holders that can be attached below the respective grinding unit.

[0006] It is an object of the present invention to provide a coffee maker in which the operator of the coffee maker has the possibility to prepare a coffee beverage in which not only one single kind of coffee beans is used for preparing the coffee beverage.

[0007] To meet this and other objects, the present invention provides, according to a first aspect, a coffee maker having a coffee bean container adapted to receive whole coffee beans to be ground and being subdivided into at least two compartments. At least two coffee grinder assemblies are provided, each assigned to one of said at least two compartments and adapted to grind said whole coffee beans contained in said assigned compartment. A brewing module has a brewing chamber adapted to receive the ground coffee from said at least two coffee grinder assemblies and to extract the ground coffee by means of hot brewing water. Further provided is at least one pre-selector means adapted to vary the amount of coffee beans to be gathered from each of said compartments and to be ground by the grinding assembly assigned thereto and used for brewing a coffee beverage.

[0008] According to a second aspect of the invention, the coffee maker has at least two coffee bean containers adapted to receive whole coffee beans to be ground and at least two coffee grinder assemblies, each assigned to one of said at least two coffee bean containers and adapted to grind said whole coffee beans contained in said assigned coffee bean container. A brewing module has a brewing chamber adapted to receive the ground coffee from said at least two coffee grinder assemblies and to extract the ground coffee by means of hot brewing water. Further provided is at least one pre-selector means adapted to vary the amount of coffee beans to be gathered from each of said coffee bean containers and to be ground by the grinding assembly assigned thereto and used for brewing a coffee beverage.

[0009] Due to the fact that the coffee maker is provided with preselecting means to pre-select the proportional amount of coffee beans discharged from each compartment and coffee bean container, respectively, ground by the coffee grinder assembly assigned to that particular compartment and coffee bean container, respectively, and finally used to brew the desired flavor of coffee beverage can be varied, the operator can use both kinds of coffee beans for preparing a coffee beverage. Alternatively, a coffee beverage can be selected that is prepared using coffee beans exclusively from one or the other one of the compartments and coffee bean containers, respectively.

[0011] The coffee maker 1 comprises a coffee bean container 2, which is subdivided into two compartments 2a, 2b by means of a partition wall 3. Below the compartment 2a, a first coffee grinder assembly 4 is located, and below the compartment 2b, a second coffee grinder assembly 8 is located. The first coffee grinder assembly 4 comprises two grinding wheels 6a, 6b, the lower grinding wheel 6a being driven by an electric motor 5 and the upper grinding wheel 6b being stationary fixed in the housing of the coffee grinder assembly 4. Correspondingly, the second coffee grinder assembly 8 comprises two grinding wheels 10a, 10b, the lower grinding wheel 10a being driven by an electric motor 9 and the upper grinding wheel 10b being stationary fixed in the housing of the coffee grinder assembly 8. Moreover, the coffee maker 1 comprises a brewing module 12 provided with a brewing chamber 13, serving for extracting the ground coffee beans by means of hot pressurized brewing water. The brewing module 12 is provided with an outlet 14 for the prepared coffee beverage.

[0012] Such a coffee bean container 2 having two separate compartments is particularly suited to receive two different blends or flavors of coffee beans. For example, the one compartment 2a may receive Arabica coffee beans and the other compartment 2b may receive Columbia coffee beans. Another possibility is to fill in normal coffee beans into one of the compartments, and to fill in decaffeinated coffee beans into the other compartment, such that, if required, anytime a partly or fully decaffeinated coffee beverage can be prepared without the need to replace coffee beans in the coffee bean container.

[0013] Each grinder assembly 4,8 is provided with an outlet 16, 17 to release the ground coffee powder. Both outlets 16, 17 open into a common feeding channel 18 through which the brewing chamber 13 is filled with coffee powder. The feeding channel 18 extends substantially in a vertical direction such that the ground coffee powder is fed through the feeding channel 18 into the brewing chamber 13 under the influence of gravity. Preferably, the brewing module 12 is pivotable about an axis 25 as shown in FIG. 1 between a feed position and a brewing position, in which the ground coffee powder is received in the brewing chamber 13 in a compressed state. The means for pivoting the brewing module 12 are not shown in the drawing.

[0014] The coffee maker 1 further comprises a preselector 20, e.g. in the form of a slide control member 22, e.g. a slide potentiometer, equipped with a scale 21. The preselector 20 serves for selecting the proportional amount of coffee beans to be fed from each of the two compartments 2a, 2b to the associated coffee grinder assembly 4, 8 to be ground therein and released to the brewing chamber 13. As shown in the drawing, in this embodiment, the slide control member 22 is in the position 75/25; this means that 75% of the total amount of coffee beans required for brewing the coffee beverage are taken from the left side of the compartment 2b, while the remaining 25% are taken from the right side compartment 2a. The slide control member 22 is connected to an electronic control unit 24 by means of which the two coffee grinder assemblies 4, 8 are individually and independently activated by employing sensors 23 for detecting the number of revolutions performed by the grinder assemblies 4, 8. The electronic sensors 23 are connected to the control unit 24 which is adapted to selectively vary the number of revolutions to be performed by the grinding assemblies, in accordance with the position of the slide control member 22. In other words, in the present example the left side coffee bean grinder 8 is activated by the control unit 24 to grind 75% of the total amount of coffee beans required for a coffee beverage, and the side coffee bean grinder 4 is activated by the control unit 24 to grind 25% of the total amount of coffee beans required for the coffee beverage.

[0015] If a coffee powder mixture is to be used for preparing a coffee beverage, preferably, the two grinder assemblies are operated simultaneously at least during a certain time period to ensure that the two coffee flavors are mixed already in the feeding channel 18 and that a homogenous mixture of coffee powder is fed to the brewing chamber 13. The simultaneous operation of the two grinding assemblies 4, 8 has the further advantage that the grinding operation is shortened as far as the time is concerned. It is understood that the two grinding assemblies are activated one after the other one.

[0016] By moving the slider of the control member 22 to the left or to the right, the proportional amount of coffee beans to be gathered from the left side compartment 2b and the right side compartment 2a, respectively, can be adjusted. .

[0017] With the preselector of the present embodiment and as shown in the drawings, five different ratios can be preselected:

[0018] 100% from the left compartment 2b and 0% from the right compartment 2a;

[0019] 75% from the left compartment 2b and 25% from the right compartment 2a;

[0020] 50% from the left compartment 2b and 50% from the right compartment 2a;

[0021] 25% from the left compartment 2b and 75% from the right compartment 2a ; and

[0022] 0% from the left compartment 2b and 100% from the right compartment 2a.

[0023] However, it is understood that this is only an example and any other graduation can be realized, even a continuous variation of the amounts of coffee beans to be gathered from the left side container 2b and the right side container 2a, respectively. Instead of a slide control member 22, a rotary control member, a rotary/push button control member or a plurality of push buttons, as the case may be even programmable, could be provided. Even a selection by means of a touch sensor or an approach sensor, for example a touch-screen display, would be possible.

[0024] A considerable advantage of a coffee maker 1 designed according the invention and along the lines described herein above may be seen in the fact that only one particular coffee bean flavor is ground in each of the two grinder assemblies 4, 8, due to the direct assignment of one of the grinder assemblies 4, 8 to one of the compartments 2a, 2b, respectively. Thus, always the same flavor of coffee beans is ground in each of the two grinder assemblies 4, 8, avoiding the drawback that residual amounts of coffee beans with another flavor could be present in the grinder assembly 4 and 8, respectively. On the other side, it is possible to use different coffee beans flavor for brewing a coffee beverage without the need to change the content of the coffee bean container, thereby rendering it possible to vary the taste of the resulting coffee beverage over a wide range by varying the proportional amounts gathered from the two compartments 2a, 2b.

[0025] Finally, it should be noted that the invention is not limited to the provision of two coffee bean compartments; it is understood that three or even more compartments could be provided, each having its own grinder assembly assigned to it. Moreover, it is also possible to provide two or more separate coffee bean containers instead of one subdivided container, each of these coffee bean containers discharging the its coffee beans to a separate coffee grinder assembly assigned to that particular coffee bean container.