Brewing unit for brewing coffee, and coffee machine containing the brewing unit

Abstract

The invention relates to a brewing unit for brewing coffee, said brewing unit containing a funnel for ground coffee, a brewing cylinder with a lower and at least one upper brewing piston, and at least one drive device which has at least one first electric motor. The brewing unit contains a frame and a slide which is mounted on the frame and which can be moved within the frame, said slide having an upper face and a lower face. The funnel for ground coffee and the at least one upper brewing piston are arranged next to each other on the slide and extend from the upper face in the direction of the lower face of the slide in each case (i.e. a narrower outlet of the funnel and a brewing filter of the upper brewing piston are located on the lower face of the slide in each case). The drive device is suitable for moving the slide within the frame such that, selectively, the funnel or the at least one brewing piston can be arranged over an opening of the brewing cylinder. By virtue of the aforementioned movement within the frame, the structural height of the brewing unit relative to aforementioned brewing units can be reduced. The invention additionally relates to a coffee machine comprising said brewing unit.

Description

[0001] Brewing unit for brewing coffee and coffee machine containing the brewing unit

[0002] A brewing unit for brewing coffee is provided, comprising a funnel for ground coffee, a brewing cylinder with a lower and at least one upper brewing piston, and at least one drive device having at least one first electric motor. The brewing unit includes a frame and a carriage mounted on the frame and movable within the frame, said carriage having a top side and a bottom side. The funnel for ground coffee and the at least one upper brewing piston are arranged side by side on the carriage and each extend from the top side towards the bottom side of the carriage (i.e., a narrower outlet of the funnel and a brewing sieve of the upper brewing piston are each located on the bottom side of the carriage). The drive device is suitable for moving the carriage within the frame, so that above an opening of the

[0003] The funnel or the at least one brewing piston can be arranged (selectively) in the brewing cylinder. By this displacement within the frame, the overall height of the brewing unit can be reduced compared to named brewing units. Furthermore, a coffee machine with this brewing unit is provided. Brewing units are known in the prior art in which the funnel for ground coffee and the upper brewing piston are arranged at a fixed point (i.e. immovable point) in the brewing unit. This has the disadvantage that the brewing unit has to be designed to be relatively large (particularly high when viewed from the base) in order, on the one hand, to enable the brewing cylinder to be filled with ground coffee via the funnel and, on the other hand, to enable the upper brewing piston to be moved into the brewing cylinder in order to start a brewing process.

[0004] Based on this, the object of the present invention was to provide a brewing unit that does not have this disadvantage. In particular, the brewing unit should enable filling the brewing cylinder with ground coffee through the brewing unit's funnel and moving the upper brewing piston into the brewing cylinder of the brewing unit, i.e., ultimately providing brewed coffee, in a more compact design (especially a lower design). Furthermore, a coffee machine should be provided that enables brewed coffee to be provided in a more compact design.

[0005] The problem is solved by the brewing unit having the features of claim 1 and the coffee machine having the features of claim 11. The dependent claims show advantageous developments.

[0006] According to the invention, a brewing unit for brewing coffee is provided, comprising a) a funnel with an inlet for filling coffee grounds and an outlet for dispensing coffee grounds; b) at least one upper brewing piston for brewing coffee; c) a lower brewing piston for brewing coffee; d) a brewing cylinder with an upper opening and a lower opening, wherein the upper opening is suitable for receiving the upper brewing piston and the lower opening is suitable for receiving the lower brewing piston; and e) at least one drive device having at least one first electric motor;characterized in that the brewing unit includes a frame and a carriage mounted on the frame, the carriage having a top side and a bottom side, the carriage being movable within the frame, the funnel and the at least one upper brewing piston being arranged side by side on the carriage, the funnel and the at least one upper brewing piston each extending from the top side of the carriage towards the bottom side of the carriage, the drive device (via the at least one first electric motor) being suitable for moving the carriage within the frame at least in such a way that the outlet for dispensing ground coffee from the funnel or the at least one upper brewing piston can be arranged above the top opening of the brewing cylinder.

[0007] With the brewing unit according to the invention, it is possible, in a more compact (especially lower design), to fill the brewing cylinder with coffee grounds through the funnel and to move the brewing cylinder towards the upper brewing piston, i.e. ultimately to provide brewed coffee. The reason for this is the mobility of the funnel and the upper brewing piston, which are arranged on the carriage, within the frame, i.e. the frame, on the one hand, specifies the maximum structural extent of the movement of the carriage and, on the other hand, allows maximum freedom of movement for the carriage (and the funnel and at least one upper brewing piston located thereon) within the frame. Due to this structural limitation of the movement on the one hand and the high flexibility of the movement, the funnel and the at least one upper brewing piston can be moved selectively over the upper opening of the brewing cylinder as required in order to fulfill its function there.This eliminates the need for complicated solutions known from the state of the art, where a funnel has to be arranged next to the brewing cylinder in a space-consuming manner in order to convey ground coffee towards the upper opening of the brewing cylinder.

[0008] In a preferred embodiment, the carriage is movable within the frame by a movement selected from the group consisting of linear movement, rotary movement, pivoting movement and combinations thereof, wherein the carriage is particularly preferably movable within the frame by a linear movement (ie linearly movable in a first direction and linearly movable in a direction opposite to the first direction).

[0009] The carriage can be mounted on the frame via a (reversible) frictional connection and / or positive connection. The frictional connection and / or positive connection is suitable, on the one hand, to prevent the carriage from falling out of the frame and, on the other hand, to allow the carriage to move within the frame. The frictional connection and / or positive connection is preferably such that a user of the brewing unit can remove the carriage from the frame without the aid of tools (i.e., without tools). This allows the user to clean the carriage more quickly and easily and also to replace an existing carriage with a new one (e.g., during service work). Furthermore, replacing an existing carriage with a differently equipped carriage (e.g., a carriage with at least one different upper brewing piston) is quick and easy.In a preferred embodiment, the funnel arranged on the carriage and the at least one upper brewing piston arranged on the carriage are each arranged on the carriage via a reversible connection. In this case, these components of the carriage can also be replaced quickly and easily.

[0010] The force connection is preferably selected from the group consisting of frictional force connection, magnetic force connection and combinations thereof. The magnetic force connection is particularly preferably established via at least two, particularly preferably via at least three, in particular via at least four, permanent magnets which are arranged on the carriage and / or on the frame, very particularly preferably arranged on the underside of the carriage and / or on an upper side of the frame. The frictional force connection is preferably established via a friction force O-ring. The positive connection is preferably selected from the group consisting of bayonet closure, clip closure, labyrinth closure, latch closure, slide closure and combinations thereof.In a preferred embodiment, the carriage has at least one first structural element on a first side which extends away from the carriage, and the carriage has at least one second structural element on a second side which is opposite the first side, which extends away from the carriage, wherein the frame has at least one first groove opposite the first side of the carriage which is suitable for receiving the at least one first structural element of the carriage, and wherein the frame has at least one second groove opposite the second side of the carriage which is suitable for receiving the at least one second structural element of the carriage.Alternatively, the carriage may have at least one first groove on a first side and at least one second groove on a second side opposite the first side. The frame may have at least one first structural element opposite the first side of the carriage, which is adapted to engage in the at least one first groove of the carriage, and the frame may have at least one second structural element opposite the second side of the carriage, which is adapted to engage in the at least one second groove of the carriage. This embodiment may prevent the carriage from falling out of the frame in an even more reliable manner.

[0011] Preferably, the at least one first groove and the at least one second groove each have an interruption at a removal position of the frame, which is suitable for removing the respective structural elements from the groove and removing the slide from the frame. The respective interruptions in the grooves also allow a user to easily and quickly remove the slide from the frame (without the need for tools).

[0012] The at least one first electric motor of the drive device can have a coupling to the carriage.

[0013] The coupling to the carriage can include or consist of a stepping gear, preferably an intermittent stepping gear. Coupling via a stepping gear is advantageous because in this case the at least one first electric motor can cause both a movement of the carriage (e.g., horizontal movement of the carriage) and a movement of the brewing cylinder (e.g., vertical movement of the brewing cylinder), although different movement times and / or movement distances may be necessary for both movements. The advantage of this design is that only a single electric motor is required to produce these two different movements, allowing for an even more compact design of the brewing unit.

[0014] The coupling to the carriage can contain or consist of at least one gear and / or at least one rack.

[0015] Furthermore, the coupling to the carriage can contain or consist of at least one linear actuator, preferably a lifting magnet.

[0016] Furthermore, the coupling to the carriage may include or consist of a hydraulic coupling.

[0017] In addition, the coupling to the carriage can contain or consist of a pneumatic coupling.

[0018] Furthermore, the coupling to the carriage can be realized by designing the electric motor as a linear motor. The advantage of this is that the coupling to the carriage can be achieved very directly via the linear motor itself, thus reducing the number of components required for the brewing unit's coupling.

[0019] The at least one first electric motor of the drive device can be coupled to the brewing cylinder. This has the advantage that the at least one first electric motor can move not only the carriage but also the brewing cylinder.

[0020] The coupling to the brewing cylinder can contain or consist of a stepping gear, preferably an intermittent stepping gear.

[0021] Furthermore, the coupling to the brewing cylinder can contain at least one drive spindle. The drive spindle can be coupled to the brewing cylinder via a spindle nut. The brewing unit can have at least one second electric motor, wherein the at least one second electric motor of the brewing unit has a coupling to the brewing cylinder via a drive spindle of the brewing unit. In this embodiment, the at least one second electric motor is responsible for the movement of the brewing cylinder (e.g. vertical movement). The disadvantage is that the brewing unit requires a second electric motor and can therefore be designed to be less compact. The advantage is that no stepping gear is required in the coupling to the carriage and / or the brewing cylinder, which makes the brewing unit structurally simpler.

[0022] The coupling to the brewing cylinder may include at least one drive spindle. The drive spindle may be coupled to the brewing cylinder via a spindle nut.

[0023] The brewing unit can have at least one measuring device for determining a pressing force of the lower brewing piston on the upper brewing piston. The at least one measuring device preferably contains or consists of a force transducer. The force transducer is preferably selected from the group consisting of a load cell, strain gauge, and combinations thereof. This embodiment makes it possible to determine a brewing force, pressing force, and / or tamper force acting from the lower brewing piston on the upper brewing piston and thus also acting on a coffee cake located between the lower and upper brewing pistons.

[0024] The at least one measuring device can be mounted on the upper brewing piston. Alternatively, the at least one measuring device (or additionally a further measuring device) can be arranged on a bearing of a drive spindle of the brewing unit.

[0025] According to the invention, a coffee machine is further provided which contains a brewing unit according to the invention.

[0026] The coffee machine according to the invention is characterized in that it enables the provision of brewed coffee in a more compact design. The coffee machine can include a control unit configured to control or regulate the brewing unit of the coffee machine.

[0027] The control unit may be configured to cause the drive device to move the carriage into a grounds insertion position in which the outlet of the funnel is arranged above the upper opening of the brewing cylinder, preferably when the control unit receives or generates a signal to fill the brewing cylinder with ground coffee.

[0028] Furthermore, the control unit can be configured to cause the drive device to move the carriage into a brewing position in which the upper brewing piston is arranged above the upper opening of the brewing cylinder, preferably when the control unit receives or generates a signal to brew coffee.

[0029] Furthermore, the control unit can be configured to cause the drive device to move the carriage into a removal position in which the carriage can be removed from the frame, preferably when the control unit receives or generates a signal to remove the carriage. In the removal position, structural elements of the carriage are particularly preferably arranged at a location of the frame grooves at which the frame grooves have an interruption, or structural elements of the frame are arranged at a location of the frame grooves at which the frame grooves have an interruption.

[0030] Furthermore, the control unit can be configured to cause the drive device to move the brewing cylinder in a direction toward the upper brewing piston, preferably when the control unit receives or generates a signal to brew coffee. When the control unit receives or generates a signal to brew coffee (preferably after a signal to eject a coffee grounds cake has been received or generated and a coffee grounds cake has been ejected), the control unit can also cause the lower brewing piston to be released from a component of the brewing unit (e.g., a shaft of the brewing unit) (e.g., by rotating a hook of the shaft from a corresponding receptacle on the lower brewing piston). Furthermore, the control unit can be configured to cause the brewing cylinder to move toward the upper brewing piston (while the lower brewing piston is held in place by the pivoted-in hook).Once the lower brewing piston has reached its lowest position in the brewing cylinder and has already moved a certain distance toward the upper brewing piston, the control unit can be configured to release the lower brewing piston (again) by rotating the hook. This allows the brewing cylinder to move toward the upper brewing piston together with the lower brewing piston (due to frictional force and positive locking between the brewing cylinder and the lower brewing piston).

[0031] Furthermore, the control unit can be configured to cause the drive device to move the brewing cylinder such that the brewing cylinder is moved in a direction away from the upper brewing piston when the control unit receives or generates a signal to eject a coffee grounds cake. In doing so, the brewing cylinder can move downward along the lower brewing piston until an upper edge of the lower brewing piston has reached a position that is flush with an upper edge of the brewing cylinder. "Downward along the lower piston" specifically means that the brewing cylinder is moved a further distance downward (i.e., toward a bottom of the brewing unit) than the lower brewing cylinder, so that a coffee grounds cake located on the lower brewing piston is no longer enclosed by the brewing cylinder and thus becomes accessible to and can be ejected by a mechanical ejection device of the brewing unit.If the control unit receives or generates a signal to eject a coffee grounds cake, the control unit can also cause the lower brewing piston to be fixed to a component of the brewing unit (e.g. a shaft of the brewing unit) (e.g. by rotating a hook of the shaft into a corresponding receptacle on the lower brewing piston).

[0032] Furthermore, the control unit can be configured to determine a pressing force of the lower brewing piston on the upper brewing piston. The control unit is preferably configured to use the determined pressing force to regulate a desired pressing force. Furthermore, the control unit is preferably configured to use the determined pressing force to determine seal wear of the lower and / or upper brewing piston. Furthermore, the control unit is preferably configured to use the determined pressing force to determine backlash of the lower and / or upper brewing piston. Apart from that, the control unit is preferably configured to use the determined pressing force to determine stiffness of the lower brewing piston, the upper brewing piston, the brewing cylinder and / or a drive spindle of the brewing unit.Furthermore, the control unit can be configured to use the determined pressing force to detect whether the brewing cylinder with the lower brewing piston is inserted into the control unit. Furthermore, the control unit can be configured to use the determined pressing force to detect whether the upper brewing piston is missing from the brewing unit.

[0033] The subject matter of the invention will be explained in more detail with reference to the following figures, without wishing to restrict it to the specific embodiments shown here.

[0034] Figure 1 schematically shows part of a brewing unit according to the invention. The funnel 1, with an inlet for filling with ground coffee and an outlet for dispensing ground coffee, is arranged next to the upper brewing piston 2 on the carriage 5, wherein the carriage 5 is held by the frame 4. The first electric motor 3 of the drive device is connected to the carriage 5 via a coupling 12 and transmits a moving force to the carriage 5, which in this case causes a linear movement of the carriage 5 within the frame 4. A second electric motor 13 of the device is connected to a drive spindle 10 of the brewing unit via a coupling 14 and transmits a moving force to a coupling 11 of the drive spindle 10 to the brewing cylinder 20, whereby the brewing cylinder can be moved towards and away from the upper brewing piston 2.The brewing cylinder can carry the lower brewing piston 21 via frictional force and positive locking if it is not attached to the brewing unit (e.g. hooked).

[0035] Figure 2 schematically shows part of a brewing unit according to the invention for brewing coffee. The brewing unit contains a funnel 1 with an inlet for filling coffee grounds and an outlet for dispensing coffee grounds, at least one upper brewing piston 2 for brewing coffee, a lower brewing piston 21 for brewing coffee, a brewing cylinder 20 with an upper opening and a lower opening, and a drive device comprising a first electric motor. The brewing unit is characterized in that it contains a frame 4 and a carriage 5 held by the frame 4, the carriage 5 having a top side and a bottom side. The frame 4 and carriage 5 are designed such that movement of the carriage 5 within the frame 4 is possible. This movement is driven by the first electric motor of the drive device of the brewing unit.The funnel 1 and the at least one upper brewing piston 2 are arranged side by side on the carriage 5. It can be seen in Figure 1 that the funnel 1 and the at least one upper brewing piston 2 each extend from the top of the carriage toward the bottom of the carriage. The drive device of the brewing unit is suitable for moving the carriage 5 within the frame 4 at least in such a way that the outlet for dispensing ground coffee from the funnel 1 or the at least one upper brewing piston 2 can be arranged above the upper opening of the brewing cylinder 20. This thus enables a selective arrangement and, as required, realizable arrangement of the funnel 1 above the upper opening of the brewing cylinder 20 (for filling ground coffee) and / or of the at least one upper brewing piston 2 (or even another upper brewing piston, which is also arranged on the carriage) above the upper opening of the brewing cylinder 20 (for brewing coffee).The left-hand illustration of Figure 2 shows a flour insertion position of the carriage 5, in which the outlet of the funnel 1 is arranged above the upper opening of the brewing cylinder 20. The middle illustration of Figure 2 shows a removal position of the carriage 5, in which the carriage 5 can be removed from the frame 4 (structural elements 7, 7' of the carriage are arranged here at interruptions 9, 9' of the grooves 8, 8' of the frame). The right-hand illustration of Figure 2 shows a brewing position of the carriage 5, in which the upper brewing piston 2 is arranged above the upper opening of the brewing cylinder 20.

[0036] Figure 3 schematically shows various arrangements of the funnel 1 and the upper brewing piston 2 of the carriage and the brewing cylinder 20 and lower brewing piston 21 during a coffee brewing cycle. In a first arrangement 15 (arrangement when filling the brewing piston 20 with ground coffee), the funnel 1 is arranged above the brewing cylinder 20. In the second arrangement 16 (arrangement when brewing coffee), the upper brewing piston 2 is arranged above the brewing cylinder 20. In the third arrangement 17 (arrangement when ejecting a coffee grounds cake 22 by an ejector 23), the brewing cylinder 20 and the lower brewing piston 21 are moved to a lowermost position, and the lower brewing piston 21 is firmly connected to the brewing unit by a hook 24.In the fourth arrangement 18 (arrangement after the coffee grounds cake 22 has been ejected by the ejector 23), the lower brewing piston 21 is still firmly connected to the brewing unit by the hook 24, so that the brewing cylinder 20 can move upwards on its own, with this movement causing the ejector 23 to move back to its original position. In the fifth arrangement 19 (arrangement when the funnel 1 is moved over the brewing cylinder 20), the lower brewing piston 21 is unhooked from the hook 24, so that the lower brewing piston 21, after a renewed movement into the first arrangement (filling the brewing cylinder 20 with more ground coffee), can move together with the brewing cylinder 20 (via frictional force) into the second arrangement 16 (arrangement when brewing another coffee) (due to frictional force between the lower brewing piston 21 and the brewing cylinder 20).

[0037] 1: Funnel with an inlet for filling coffee grounds and a

[0038] Outlet for dispensing coffee grounds;

[0039] 2: upper brewing piston;

[0040] 3: first electric motor of the drive device;

[0041] 4: frame;

[0042] 5: sled;

[0043] 6: permanent magnet(s);

[0044] 7: first structural element of the carriage;

[0045] 7': second structural element of the carriage;

[0046] 8: first groove;

[0047] 8': second groove;

[0048] 9: Interruption of the first groove;

[0049] 9': interruption of the second groove;

[0050] 10: Drive spindle for driving the brewing cylinder;

[0051] 11: Coupling of the drive spindle to the brewing cylinder;

[0052] 12: Coupling of the first electric motor of the drive device with the carriage (e.g. gear-rack coupling);

[0053] 13: second electric motor of the brewing unit; 14: coupling of the second electric motor of the brewing unit to the

[0054] Brewing cylinder (via a drive spindle of the brewing unit);

[0055] 15: first arrangement of funnel and upper brewing piston of the carriage and the brewing cylinder and lower brewing piston (filling the brewing cylinder with ground coffee);

[0056] 16: second arrangement of funnel and upper brewing piston of the carriage and the brewing cylinder and lower brewing piston (brewing coffee);

[0057] 17: third arrangement of funnel and upper brewing piston of the carriage and the brewing cylinder and lower brewing piston (ejecting a coffee grounds cake);

[0058] 18: fourth arrangement of funnel and upper brewing piston of the carriage and the brewing cylinder and lower brewing piston (after ejecting a coffee grounds cake);

[0059] 19: fifth arrangement of funnel and upper brewing piston of the carriage and the brewing cylinder and lower brewing piston (moving the funnel over the brewing cylinder);

[0060] 20: Brewing cylinder;

[0061] 21: lower brewing piston;

[0062] 22: Coffee grounds cake;

[0063] 23: Ejector for ejecting coffee grounds cake;

[0064] 24: Hook for hooking the lower brewing piston.

Claims

Patent claims 1. A brewing unit for brewing coffee, comprising a) a funnel with an inlet for filling coffee grounds and an outlet for dispensing coffee grounds; b) at least one upper brewing piston for brewing coffee; c) a lower brewing piston for brewing coffee; d) a brewing cylinder with an upper opening and a lower opening, wherein the upper opening is suitable for receiving the upper brewing piston and the lower opening is suitable for receiving the lower brewing piston; and e) a drive device having at least one first electric motor;characterized in that the brewing unit includes a frame and a carriage held by the frame, the carriage having a top side and a bottom side, the carriage being movable within the frame, the funnel and the at least one upper brewing piston being arranged side by side on the carriage, the funnel and the at least one upper brewing piston each extending from the top side of the carriage towards the bottom side of the carriage, the drive device being suitable for moving the carriage within the frame at least in such a way that the outlet for dispensing ground coffee from the funnel or the at least one upper brewing piston can be arranged above the top opening of the brewing cylinder.

2. Brewing unit according to the preceding claim, characterized in that the carriage is movable within the frame by a movement selected from the group consisting of linear movement, rotary movement, pivoting movement and combinations thereof.

3. Brewing unit according to one of the preceding claims, characterized in that the carriage is held by the frame via a force connection, wherein the force connection is preferably i) a frictional force connection, which is particularly preferably established via at least one frictional force O-ring arranged on the carriage and / or on the frame; and / or ii) a magnetic force connection, which is preferably established via at least two, particularly preferably via at least three, in particular via at least four, permanent magnets arranged on the carriage and / or on the frame; and / or iii) prevents the carriage from falling out of the frame due to gravity, preferably prevents the carriage from falling out of the frame due to gravity at least in a removal position of the carriage within the frame.

4. Brewing unit according to one of the preceding claims, characterized in that the carriage is held by the frame via a positive connection, wherein the positive connection is preferably i) selected from the group consisting of a bayonet lock, clip lock, labyrinth lock, latch lock, slide lock, and combinations thereof; and / or ii) prevents the carriage from falling out of the frame due to gravity, preferably prevents the carriage from falling out of the frame due to gravity at least in a removal position of the carriage within the frame.

5. Brewing unit according to one of the preceding claims, characterized in that the carriage i) has at least one first structural element on a first side extending away from the carriage, and the carriage has at least one second structural element on a second side opposite the first side extending away from the carriage, wherein the frame opposite the first side of the carriage has at least one first groove suitable for receiving the at least one first structural element of the carriage, and wherein the frame opposite the second side of the carriage has at least one second groove suitable for receiving the at least one second structural element of the carriage, or ii) has at least one first groove on a first side and the carriage has at least one second groove on a second side opposite the first side,wherein the frame has at least one first structural element opposite the first side of the slide, which is suitable for engaging in the at least one first groove of the slide, and wherein the frame has at least one second structural element opposite the second side of the slide, which is suitable for engaging in the at least one second groove of the slide; wherein preferably the at least one first groove and the at least one second groove each have an interruption at a removal position of the frame, which is suitable for removing the respective structural elements from the groove and removing the slide from the frame.

6. Brewing unit according to one of the preceding claims, characterized in that the at least one first electric motor of the drive device has a coupling to the carriage, wherein the coupling preferably i) contains or consists of a stepping gear, preferably an intermittent stepping gear; and / or ii) contains or consists of at least one gear, at least one rack, at least one toothed belt and / or at least one chain; and / or iii) contains or consists of at least one linear actuator, preferably a solenoid; and / or iv) contains or consists of a hydraulic coupling; and / or v) contains or consists of a pneumatic coupling; and / or; and / or vi) is realized by designing the electric motor as a linear motor.

7. Brewing unit according to one of the preceding claims, characterized in that the at least one first electric motor of the drive device has a coupling to the brewing cylinder, wherein the coupling preferably i) contains or consists of a stepping gear, preferably an intermittent stepping gear; and / or ii) contains at least one drive spindle.

8. Brewing unit according to one of the preceding claims, characterized in that the brewing unit has at least one second electric motor, wherein the at least one second electric motor of the brewing unit has a coupling to the brewing cylinder via a drive spindle of the brewing unit.

9. Brewing unit according to one of the preceding claims, characterized in that the brewing unit has at least one measuring device for determining a pressing force of the lower brewing piston on the upper brewing piston, wherein the at least one measuring device preferably contains or consists of a force transducer, wherein the force transducer is preferably selected from the group consisting of a load cell, strain gauges and combinations thereof.

10. Brewing unit according to the preceding claim, characterized in that the at least one measuring device is i) attached to the upper brewing piston; and / or ii) arranged on a bearing of a drive spindle, wherein the drive spindle is suitable for moving the brewing cylinder and the lower brewing piston toward the upper brewing piston, wherein the drive spindle is preferably connected to an electric motor, optionally the electric motor of the drive device.

11. Coffee machine comprising a brewing unit according to one of the preceding claims.

12. Coffee machine according to claim 11, characterized in that the coffee machine includes a control unit configured to control or regulate the brewing unit of the coffee machine.

13. Coffee machine according to claim 12, characterized in that the control unit is configured to cause the drive device to move the carriage i) into a grounds insertion position, in which the outlet of the funnel is arranged above the upper opening of the brewing cylinder, preferably when the control unit receives or generates a signal for filling the brewing cylinder with ground coffee; and / or ii) into a brewing position, in which the at least one upper brewing piston is arranged above the upper opening of the brewing cylinder, preferably when the control unit receives or generates a signal for brewing coffee; and / or iii) into a removal position, in which the carriage can be removed from the frame, preferably when the control unit receives or generates a signal for removing the carriage, wherein in the removal position, structural elements of the carriage are particularly preferably arranged at a location of grooves of the frame are arranged at which the grooves of the frame have an interruption or structural elements of the frame are arranged at a location of grooves of the carriage at which the grooves of the carriage have an interruption.

14. Coffee machine according to one of claims 12 or 13, characterized in that the control unit is configured to cause the drive device to move the brewing cylinder i) in a direction toward the upper brewing piston, preferably when the control unit receives or generates a signal to brew coffee; and / or ii) in a direction away from the upper brewing piston, preferably when the control unit receives or generates a signal to eject a coffee grounds cake.

15. Coffee machine according to one of claims 12 to 14, characterized in that the control unit is configured to determine a pressing force of the lower brewing piston on the upper brewing piston and preferably to use the determined pressing force for i) regulating a desired pressing force; and / or ii) determining seal wear of the lower and / or upper brewing piston; and / or iii) determining backlash of the lower and / or upper brewing piston; and / or iv) determining stiffness of the lower brewing piston, the upper brewing piston, the brewing cylinder and / or a drive spindle of the brewing unit; and / or v) detecting whether the brewing cylinder with the lower brewing piston is inserted into the control unit; and / or vi) detecting whether the upper brewing piston is missing from the brewing unit.

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