Brewing unit and coffee machine

Abstract

The invention relates to a brewing unit which contains an upper brewing piston, a lower brewing piston, a brewing cylinder, a drive device which has at least one electric motor, and an ejection device. The ejection device has an ejector blade which is rotatably secured to the brewing cylinder. The brewing unit additionally contains a shaft which has an ejector lever and a locking element. The at least one electric motor of the drive device is suitable for rotating the shaft in a first rotational direction and in a second rotational direction opposite the first rotational direction. The ejector lever is suitable for transmitting a force to the ejection device by rotating the shaft in the first rotational direction so that the ejector blade of the ejection device is moved over the brewing filter surface of the lower brewing piston. The invention additionally relates to a coffee machine comprising the brewing unit according to the invention.

Description

[0001] Brewing unit and coffee machine

[0002] A brewing unit is provided which includes an upper brewing piston, a lower brewing piston, a brewing cylinder, a drive device having at least one electric motor, and an ejection device.

[0003] The ejection device has an ejector blade that is rotatably attached to the brewing cylinder. The brewing unit further includes a shaft that has an ejector lever and a locking element. The at least one electric motor of the drive device is suitable for rotating the shaft in a first direction of rotation and in a second direction opposite to the first direction of rotation.

[0004] Direction of rotation. The ejector lever is suitable for transmitting a force to the ejection device by a rotational movement of the shaft in the first direction of rotation, so that the ejector scoop of the ejection device is moved over the brewing sieve surface of the lower brewing piston. Furthermore, a coffee machine with the brewing unit according to the invention is provided. In conventional brewing units, the mechanism for ejecting coffee grounds cake into an interior of a grounds container of the coffee machine is positively guided and is driven by a main drive motor of the brewing unit. This has the disadvantage that the type and speed of movement of the ejection element for ejecting a coffee grounds cake are limited.

[0005] Due to the limited capacity of conventional coffee machine brewing units to transport coffee grounds, the coffee grounds' ejection characteristic cannot be changed. In other words, the coffee grounds always "fly" to the same spot inside the grounds container of conventional coffee machines due to the action of the ejector blade of these brewing units. The disadvantage of this is that a sloping mountain of coffee grounds builds up locally at this point, the sides of which would still allow coffee grounds to be collected in the grounds container, but this space is not used by conventional coffee machines. The result is that the coffee machine fills the grounds container from one side, and the entire available space of the grounds container is not utilized.This means that the grounds container in these coffee machines needs to be emptied prematurely, even though there would still be room in the container for more coffee grounds. More optimal use of the interior of these coffee machines' grounds containers as a container for coffee grounds (i.e., coffee waste) would extend the useful life of the grounds containers until they are emptied, saving users effort and time.

[0006] Based on this, the object of the present invention was to provide a brewing unit that overcomes at least one disadvantage of the prior art. In particular, the brewing unit should allow for greater flexibility in the type and speed of movement of the ejector blade, e.g., movement of the ejector blade to its initial position ("reset movement") by movement of the brewing cylinder. Preferably, a brewing unit should also be provided that enables longer use of a coffee machine's grounds container or that allows a coffee machine user to spend less effort and time on repeatedly emptying the grounds container. This object is achieved by the brewing unit having the features of claim 1 and the coffee machine having the features of claim 10. The dependent claims disclose advantageous developments.

[0007] According to the invention, a brewing unit is provided, comprising a) an upper brewing piston for brewing coffee, wherein the upper brewing piston has a brewing sieve surface; b) a lower brewing piston for brewing coffee, wherein the lower brewing piston has a brewing sieve surface; c) 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; d) a drive device having at least one electric motor;and e) an ejection device comprising an ejector scoop, characterized in that the ejector scoop is rotatably attached to the brewing cylinder, wherein the brewing unit includes a shaft having an ejector lever and a locking element, wherein the at least one electric motor of the drive device is suitable for rotating the shaft in a first direction of rotation and in a second direction of rotation which is opposite to the first direction, wherein the ejector lever is suitable for transmitting a force to the ejection device by a rotational movement of the shaft in the first direction of rotation, so that the ejector scoop of the ejection device is moved over the brewing sieve surface of the lower brewing piston.;

[0008] The brewing unit according to the invention has the advantage that it allows more flexibility in the type and speed of movement of the ejector blade, e.g., a movement of the ejector blade to its starting position ("reset movement") by a movement of the brewing cylinder. This is made possible by the fact that the ejector blade is rotatably attached to the brewing cylinder, since this enables a movement of the ejector blade ("reset movement") by a movement of the brewing cylinder, in particular by a movement of the brewing cylinder in the direction of the upper brewing piston.

[0009] In addition, the brewing unit according to the invention has the advantage that the locking element on the shaft allows the lower brewing piston to be fixed to the shaft (i.e., "locked"), thereby preventing movement of the lower brewing piston together with the brewing cylinder (via frictional force) away from the shaft (i.e., upwards or toward the upper brewing piston). An upward movement of the brewing cylinder can be carried out following the ejection of an already brewed coffee grounds cake. Said movement and the fixing of the lower brewing piston to the shaft by the locking element create a free space inside the brewing cylinder, which creates space for the intake of new ground coffee, which in turn is available for a new brewing process.

[0010] Furthermore, the brewing unit according to the invention has the advantage that the electric motor of the drive device can generate a rotation of the shaft at different speeds. This allows the ejector lever to act on the ejector device at different speeds, so that the ejector scoop can be moved across the brewing sieve surface at different speeds. Consequently, a coffee grounds cake located on the brewing sieve surface can be transported by the ejector scoop to various points within the interior of a grounds container, allowing optimal use of the interior of the grounds container and reducing the user's effort and time spent repeatedly emptying the grounds container. For example, the coffee grounds cake "flies" the furthest into the grounds container at full speed and the shortest distance at the lowest speed.

[0011] By increasing or decreasing the ejector speed (i.e. by controlling the power consumption of the electric motor), the ejection characteristic of the coffee grounds cake (or the shearing of the coffee grounds cake from the brewing sieve surface of the brewing piston when the coffee grounds cake is greater) can be influenced and the interior of the grounds container can be used optimally, i.e. it can be filled more with coffee grounds cake before it needs to be emptied than with conventional coffee machines (i.e. after a larger number of brewings). This also makes it possible to achieve the same number of brewings before the grounds container needs to be emptied with a smaller grounds container, i.e. the grounds container of the coffee machine can be designed to be more compact, which is an advantage if more space is needed in the coffee machine for existing or additional components.However, the entire coffee machine can also be designed to be more compact, for example if more space is not needed inside the coffee machine.

[0012] In an advantageous embodiment, the locking element of the shaft is suitable for fixing the lower brewing piston to the shaft by moving the shaft in the first direction of rotation. This embodiment allows the brewing cylinder to be moved towards the upper brewing piston of the brewing unit without the lower brewing piston by moving the shaft, i.e. the drag force (frictional force) that would otherwise act between the lower brewing piston and brewing cylinder can be overcome by rotating the shaft and thereby fixing the lower brewing piston to the shaft. This allows the lower brewing cylinder to be moved out of the interior of the brewing cylinder, freeing the interior of the brewing cylinder to receive new ground coffee.

[0013] Furthermore, the locking element of the shaft is preferably adapted to release the lower brewing piston from the shaft by moving the shaft in the second direction of rotation. This allows the lower brewing piston to be moved (again) together with the brewing cylinder (through frictional force) (i.e., further toward the upper brewing piston or in the opposite direction).

[0014] Furthermore, the locking element can contain or consist of a locking hook, preferably a locking hook that is suitable for hooking the lower brewing piston onto the shaft by moving the shaft in the first direction of rotation and for unhooking the lower brewing piston from the shaft by moving the shaft in the second direction of rotation. A locking hook as a locking element has the advantage of being a very simple and reliable locking element. The ejection device can have a mechanical coupling that is suitable for absorbing a force of the ejector lever, which is generated by moving the shaft in a first direction, and for moving the ejector scoop over the brewing sieve surface of the lower brewing piston.

[0015] In a preferred embodiment, the lower brewing piston has a planar brewing sieve surface and the mechanical coupling is suitable for absorbing a force of the ejector lever, which is generated by a movement of the shaft in the first direction of rotation, and for moving the ejector scoop in a linear direction over the brewing sieve surface of the lower brewing piston. An advantage of this embodiment is that even a planar brewing sieve surface of the lower brewing piston can be thoroughly freed of coffee grounds cake, i.e. the planar brewing sieve surface on the lower brewing piston can be wiped more cleanly by the ejector scoop than with a non-planar (e.g. convex) brewing sieve surface, since the distance between the ejector scoop and the brewing sieve surface remains constant throughout the entire movement over the brewing sieve surface. A planar brewing sieve surface on the lower brewing piston is advantageous because it increases the quality of the brewed coffee.This is because a coffee cake can be brewed that has a cylindrical shape with parallel bases, whereby water flows through the coffee cake for an equal length at every point on the bases in a direction perpendicular to these two bases. This would not be the case with a concave and / or convex brewing sieve surface. To enable brewing of a cylindrical coffee grounds cake, in a preferred embodiment, the upper brewing piston also has a planar brewing sieve surface.

[0016] The brewing unit, preferably the ejection device, particularly preferably a mechanical coupling of the ejection device, can comprise a substantially L-shaped structural element having a shorter and a longer section and being rotatably attached to the brewing cylinder at the intersection of the shorter and longer sections, wherein the longer section of the L-shaped structural element is further rotatably attached to the ejector blade. As a result, the ejector blade is also rotatably attached to the brewing cylinder.The L-shaped structural element is preferably suitable for moving the ejector blade, preferably in a linear ejection direction, over the brewing sieve surface of the lower brewing piston by a rotational movement of the L-shaped structural element in a first direction of rotation, wherein in particular the ejector lever of the shaft of the coffee machine is suitable for exerting a force on the longer section of the L-shaped structural element by a rotation of the shaft in the first direction of rotation of the shaft and for causing a rotational movement of the L-shaped structural element in the first direction of rotation of the L-shaped structural element.

[0017] Furthermore, the L-shaped structural element is preferably suitable for moving the ejector blade in a preferably linear, retraction direction, which is opposite to the ejection direction, over the brewing sieve surface of the lower brewing piston by a rotational movement of the L-shaped structural element in a second direction of rotation, which is opposite to the first direction, wherein in particular the ejector lever of the shaft of the coffee machine is suitable, by remaining in the ejection position and a movement of the brewing cylinder in a direction towards the upper brewing piston, to exert a force on the shorter section of the L-shaped structural element and to effect the rotational movement of the L-shaped structural element in the second direction of rotation of the L-shaped structural element.

[0018] In a further advantageous embodiment, the brewing cylinder is connected to the brewing unit via an element for reversibly receiving the brewing cylinder, wherein the element is preferably suitable for establishing a (reversible) connection between the brewing cylinder and the element, which is selected from the group consisting of a locking pin closure, a bayonet closure, and combinations thereof. The advantage here is that the brewing cylinder, together with the associated ejection device, can be easily removed from the coffee machine by a user of the coffee machine, cleaned outside the coffee machine, and reinserted into the coffee machine. Furthermore, a simple and quick replacement of a brewing cylinder is possible.The same can apply to the lower brewing piston if it is not fixed to the shaft by the shaft's locking element, since the lower brewing piston is (only) connected to the brewing cylinder via frictional force and positive locking and can therefore be removed together with the brewing cylinder.

[0019] The at least one electric motor of the drive device may be suitable for rotating the shaft directly or via a coupling to the shaft.

[0020] The coupling to the shaft can contain 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 electric motor can cause both a movement of the shaft (rotational movement of the shaft) and a movement of the upper brewing piston (e.g. horizontal movement of a carriage containing the upper brewing piston), for which both movements may require different movement times and / or movement distances. The advantage of this configuration is that only a single electric motor is needed to cause these two different movements, which allows for an even more compact design of the brewing unit. Furthermore, the coupling to the shaft can contain or consist of at least one gearwheel, at least one rack, at least one toothed belt and / or at least one chain.

[0021] In a preferred embodiment, the brewing unit has a carriage containing the upper brewing piston, optionally also containing a funnel, and the at least one electric motor of the drive device has a coupling to the carriage of the brewing unit. The coupling can contain or consist of a stepping gear, preferably an intermittent stepping gear. Furthermore, the coupling to the carriage can contain or consist of at least one gear, at least one rack, at least one toothed belt, and / or at least one chain.

[0022] Apart from that, the at least one electric motor of the drive device can have a coupling to the brewing cylinder. The coupling to the brewing cylinder can contain or consist of a stepping gear, preferably an intermittent stepping gear. Coupling via a stepping gear is advantageous because the at least one electric motor can move not only the shaft (and possibly a carriage; see above), but also the brewing cylinder (e.g., vertical movement of the brewing cylinder). Furthermore, the coupling to the brewing cylinder can contain a drive spindle and / or spindle nut. The drive spindle can be coupled to the brewing cylinder via a spindle nut.

[0023] The drive device can have at least one second electric motor, wherein the at least one second electric motor of the drive device has a coupling to the brewing cylinder, wherein the at least one second electric motor of the drive device is suitable for moving the brewing cylinder in a first direction towards the upper brewing piston and in a second direction which is opposite to the first direction. In this embodiment, the at least one second electric motor (and not the at least one electric motor) is responsible for the movement of the brewing cylinder (e.g. vertical movement of the brewing cylinder). 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 there is no coupling of the at least one electric motor to the brewing cylinder and therefore no stepping gear is necessary, which makes the brewing unit structurally simpler.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.

[0024] According to the invention, a coffee machine is further provided, comprising a) a brewing unit according to the invention; b) a grounds container with an interior space for receiving brewed coffee grounds cake, wherein the grounds container is arranged below the brewing cylinder and wherein a wall of the interior space of the grounds container has a specific distance from the brewing cylinder in an ejection direction for coffee grounds cake; and c) a control unit configured to control or regulate the brewing unit of the coffee machine.

[0025] The coffee machine has the advantages also provided by the brewing unit according to the invention. The control unit can be configured to cause the drive device to rotate the shaft in the first rotational direction in order to fix the locking element of the shaft to the lower brewing piston and to move the ejector lever of the shaft toward a mechanical coupling of the ejection device, preferably toward a substantially L-shaped structural element of the brewing cylinder, particularly preferably when the control unit receives or generates a signal to eject a coffee grounds cake.

[0026] Furthermore, the control unit can be configured to cause the drive device to rotate the shaft in the second direction of rotation, which is opposite to the first direction, in order to release the locking element of the shaft on the lower brewing piston and to move the ejector lever of the shaft away from a mechanical coupling of the ejection device, preferably away from a substantially L-shaped structural element of the brewing cylinder, particularly preferably when the control unit receives or generates a signal to brew coffee.

[0027] In addition, the control unit can be configured to cause the at least one electric motor of the drive device, or at least a second electric motor of the coffee machine, to move the brewing cylinder in a direction towards the upper brewing piston, preferably when the control unit receives or generates a signal to brew coffee.

[0028] Furthermore, the control unit can be configured to cause the at least one electric motor of the drive device, or at least a second electric motor of the coffee machine, to move the brewing cylinder 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.

[0029] Furthermore, the control unit can be configured to control the electrical power of the drive device used to rotate the shaft, preferably via an electrical voltage, particularly preferably via a pulsed electrical voltage, wherein the control is carried out in particular via pulse-width modulation. Furthermore, the control unit can be configured to change the electrical power of the drive device used to rotate the shaft after a predetermined number of brewing cycles.

[0030] The control unit may be configured to reduce an electrical power of the drive device used to rotate the shaft from a first electrical power to a second electrical power, preferably such that a coffee grounds cake conveyed by the second electrical power is conveyed to a location in the interior of the grounds container that is closer to the brewing cylinder than the location to which at least one coffee grounds cake was conveyed by means of the first electrical power, wherein the first electrical power is optionally a maximum electrical power.

[0031] Furthermore, the control unit can be configured to increase an electrical power of the drive device used to rotate the shaft from a first electrical power to a second electrical power, preferably such that a coffee grounds cake conveyed by the second electrical power is conveyed to a location in the interior of the grounds container that is further away from the brewing cylinder than the location to which at least one coffee grounds cake was conveyed by means of the first electrical power, wherein the first electrical power is optionally a minimum electrical power.

[0032] Furthermore, the control unit can be configured to change an electrical power of the drive device used to rotate the shaft in such a way that the ejection device conveys a first layer of coffee grounds cakes arranged side by side into the interior of the grounds container. Particularly preferably, the control unit is configured to subsequently convey at least one further layer, preferably several layers, of coffee grounds cakes into the interior of the grounds container in this way, in particular until the interior of the grounds container is completely filled with coffee grounds cake. By introducing the coffee grounds into the interior of the grounds container in layers or in layers, the interior of the grounds container can be used to the maximum extent possible for receiving coffee grounds before the grounds container needs to be emptied.Furthermore, the control unit can be configured to change the electrical power of the drive device used to rotate the shaft in such a way that, after a certain number of brews with a certain amount of coffee powder, additional coffee grounds cakes are transported to a location within the grounds container that is closer to the brewing cylinder than the location to which the coffee grounds cakes were transported using electrical power before their change. The amount of coffee powder depends on the type of coffee product being brewed. Typical coffee powder quantities are shown in the following table.

[0033] Table

[0034] The amount of ground coffee used therefore determines the size of the coffee grounds cake. This is typically dry-pressed in the brewing unit before being ejected. During this process, the coffee machine can also detect the position of the lower brewing piston in relation to the upper brewing piston, at which point the pressing process ends. This means that the coffee machine (or its control unit) can be configured to measure the height of the coffee grounds cake, which tells the coffee machine how high it is. Thus, the amount or size of the coffee grounds cake and its number can be used to determine how far and where the coffee grounds cake is ejected via an algorithm stored in the coffee machine (or its control unit).

[0035] In this regard, the control unit can thus be configured to change the electrical power of the drive device used to rotate the shaft in such a way that, after brewing a total dry coffee powder quantity corresponding to 25% to 75% of the coffee machine's grounds container's capacity for a total dry coffee powder quantity (i.e., excluding the water portion of the total coffee powder quantity), further coffee grounds cakes are transported to a location in the interior of the grounds container that is closer to the brewing cylinder than the location to which the coffee grounds cakes were transported using electrical power before their change. In this embodiment, the coffee machine can first pile up a "mountain" of coffee grounds at a location at the bottom of the interior of the grounds container that is furthest from the brewing sieve surface of the lower brewing piston.In order to then use the "flank" of the "mountain" of coffee grounds extending towards the lower brewing piston as a collecting surface for coffee grounds, the electrical power of the second motor is reduced and thus the transport length of the coffee grounds cake into the interior of the grounds container is shortened, which enables optimal use of the interior of the grounds container.

[0036] For example, a grounds container can hold 80 coffee grounds cakes from a Cafe Creme brew, i.e., approximately 800 g of dry coffee grounds. In this case, the coffee machine's control unit can be configured, for example, to change the throwing distance after 200 g of brewed coffee grounds, 400 g of brewed coffee grounds, or 600 g of brewed coffee grounds.

[0037] 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.

[0038] Figure 1 schematically shows the function of a brewing unit according to the invention. The brewing unit contains an upper brewing piston 1 and a lower brewing piston 2 for brewing coffee, the lower brewing piston having a planar brewing sieve surface 3. The brewing unit also contains a brewing cylinder 4 with an upper opening and a lower opening, wherein the upper opening is suitable for receiving the upper brewing piston 1 and the lower opening is suitable for receiving the lower brewing piston 2. Furthermore, in this embodiment, the brewing unit contains a funnel 26 for filling and dispensing ground coffee. The brewing unit also contains a drive device (not shown) which is suitable for moving the brewing cylinder 4 (for example together with the lower brewing piston 2) in a direction towards the upper brewing piston 1 and in a direction away from the upper brewing piston 1.Furthermore, the brewing unit includes an ejection device comprising a substantially L-shaped structural element 15 rotatably attached to the brewing cylinder 4, wherein the substantially L-shaped structural element 15 is rotatably attached to the brewing cylinder 4 at the intersection 16 of its longer section and shorter section. The ejector blade 6 is rotatably attached to the substantially L-shaped structural element 15, so that the ejector blade 6 is also rotatably attached to the brewing cylinder 4. Furthermore, the shaft of the brewing unit includes an ejector lever 13, which is suitable for exerting a force on the substantially L-shaped structural element 15 (specifically: its longer section) and thus on the ejector blade 6 by rotating the shaft in the first rotational direction, and consequently moving the ejector blade 6 over the planar brewing sieve surface 3 of the lower brewing piston 2 (see the second image from the left in Figure 1).By said movement of the ejector blade 6, a coffee grounds cake 9 resting on the brewing sieve surface 3 of the lower brewing piston 2 is conveyed into the interior of a grounds container of a coffee machine. By rotating the shaft in the first direction of rotation, the locking element of the shaft is also hooked onto the lower brewing piston 2, so that the lower brewing piston is fixed to the shaft. A subsequent movement of the brewing cylinder 4 towards the upper brewing piston 1 causes the brewing piston 4 without the lower brewing cylinder 2 to be moved towards the upper brewing piston 1 and the short section of the essentially L-shaped structural element 16 to engage the ejector lever 13, causing a movement of the ejector blade 6 in the opposite direction over the brewing sieve surface 3 of the lower brewing piston 2 (return movement of the ejector blade 6) (see the 3rd and fourth images from the left in Figure 1).

[0039] Figure 2 schematically shows part of a brewing unit according to the invention. Shown is the shaft 17 of the brewing unit, which has the ejector lever 13 and the locking element 20 (here: a locking hook). In this embodiment, the shaft 17 is driven directly by the electric motor 5 of the drive device, i.e. it can be rotated in both directions of rotation by the electric motor 5 (at different speeds). Figure 3 schematically shows another part of the coffee machine according to the invention. The upper brewing piston 1 is arranged here on a carriage which is present in a frame. The carriage can be moved linearly in the frame via a gear-rack coupling 22 and by the electric motor 5 of the drive device.In this embodiment, the brewing unit has a second electric motor 12, which can rotate a drive spindle 21 and thereby move an element 14 arranged on the drive spindle for reversibly receiving the brewing cylinder (e.g., together with the brewing cylinder) up and down. In this embodiment, the first electric motor 5 is further coupled to the shaft 17 via the gears 18, 18' and the toothed belt 19 and is thus also suitable for rotating the shaft 17 in the first and second directions of rotation. This illustration also shows that the coffee machine has a second electric motor 12. By moving the shaft 17 in the first direction of rotation, the ejector lever 13 moves in the direction of the essentially L-shaped structural element 16 and exerts a force thereon (not shown).In addition, the locking element 20 moves in the direction of the lower brewing piston and fixes it to the shaft 17 (not shown).

[0040] Figure 4 shows schematically the part of the brewing unit according to the invention from Figure 3, with the difference that further elements of the brewing unit are shown. Figure 4 also shows the brewing cylinder 4, which is shown in the lower brewing piston 2, which is reversibly connected to the element 14 for reversibly receiving the brewing cylinder. The lower brewing piston 2 is located in the brewing cylinder 4 and is fixed here to the shaft 17 by the locking element 20 and thus cannot move upwards together with the brewing cylinder 4 (i.e. in the direction of the upper brewing piston 1). Rotatably attached to the brewing cylinder 4 is the essentially L-shaped structural element 15, which in turn is rotatably connected to the ejector blade 6. The ejector blade 6 is already in the reset position in the illustration in Figure 4.

[0041] Figure 5 schematically shows various arrangements of the brewing cylinder 4 and lower brewing piston 2 during part of a coffee brewing cycle. In a first arrangement 23 (arrangement when a coffee grounds cake 9 is ejected by the ejector scoop 6), the brewing cylinder 4 and the lower brewing piston 2 have moved into a lowest position. The lower brewing piston is fixed to the shaft by the locking hook 20. In the second arrangement 24 (arrangement after the coffee grounds cake 9 has been ejected by the ejector scoop 6), the brewing cylinder 4 has moved upward without the lower brewing piston 2, whereby this movement of the brewing cylinder 4 has already partially moved the ejector scoop 6 back to its original position (reset position).In the third arrangement 25 (arrangement in a position of the lower brewing piston 2 below the upper brewing piston 1), the lower brewing piston 2 is unhooked from the locking hook 20, so that the lower brewing piston 2 can move in said direction together with the brewing cylinder 4 (via frictional force and positive locking) after a renewed movement in the direction of the upper brewing piston 1.

[0042] Figure 6 schematically shows part of a coffee machine according to the invention. It shows the coffee machine's grounds container 7, which is arranged below the brewing cylinder 4 and has an interior space 8 for receiving brewed coffee grounds cake 9. A wall 10 of the interior space 8 of the grounds container 7 is at a specific distance 11 from the brewing cylinder 4 in an ejection direction for coffee grounds cake 6. This distance defines the maximum distance over which a coffee grounds cake 9 can be conveyed by the ejector scoop 6 into the interior space 8 of the grounds container 7. Three different cases are shown: In the first case, the coffee grounds cake 9 is conveyed a maximum distance into the interior space 8 of the grounds container 7 by the ejector scoop 6 (maximum power of the electric motor of the brewing unit).In the second case, the coffee grounds cake 9 is transported a medium distance into the interior 8 of the grounds container 7 by the ejector scoop 6 (medium power of the brewing unit's electric motor). In the third case, the coffee grounds cake 9 is transported a minimal distance into the interior 8 of the grounds container 7 by the ejector scoop 6 (minimal power of the brewing unit's electric motor). The illustration shows that the power of the brewing unit's electric motor, which can cause the shaft to rotate in a first direction and thus transmits its power to the ejector lever and thus the ejector scoop 6, can be used to control the position to which the coffee grounds cake 9 is transported into the interior 8 of the grounds container 7 of the coffee machine. This allows optimal use of the volume of the interior 8 of the grounds container and extends the interval until the grounds container 7 needs to be emptied.As a result, the coffee machine user has to spend less time and effort on repeatedly emptying the grounds container.

[0043] 1: upper brewing piston;

[0044] 2: lower brewing piston;

[0045] 3: Brewing sieve surface of the lower brewing piston;

[0046] 4: Brewing cylinder;

[0047] 5: electric motor;

[0048] 6: Ejector blade;

[0049] 7: Grounds container;

[0050] 8: Interior of the grounds container;

[0051] 9: Coffee grounds cake;

[0052] 10: Wall of the interior of the grounds container;

[0053] 11: specific distance between a wall of the interior of the grounds container and the brewing cylinder;

[0054] 12: second electric motor;

[0055] 13: Shaft ejector lever;

[0056] 14: Element for reversible mounting of the brewing cylinder;

[0057] 15: essentially L-shaped structural element;

[0058] 16: Intersection of the longer section and shorter section of the substantially L-shaped structural element;

[0059] 17: wave;

[0060] 18, 18': gear (e.g. belt pulley or segment gear);

[0061] 19: Timing belt;

[0062] 20: Locking element of the shaft (e.g. locking hook);

[0063] 21: drive spindle of the drive device;

[0064] 22: Gear-rack coupling for the linear movement of the upper brewing piston;

[0065] 23: first arrangement of the brewing cylinder and lower brewing piston

[0066] (Ejecting a coffee grounds cake); : second arrangement of the brewing cylinder and lower brewing piston

[0067] (After ejecting a coffee grounds cake); : third arrangement of the carriage and the brewing cylinder and lower brewing piston (brewing cylinder moved towards the upper brewing piston). : funnel for filling and dispensing ground coffee.

Claims

Patent claims 1. Brewing unit, comprising a) an upper brewing piston for brewing coffee, wherein the upper piston has a brewing sieve surface; b) a lower brewing piston for brewing coffee, wherein the lower brewing piston has a brewing sieve surface; c) 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; d) a drive device having at least one electric motor; and e) an ejection device having an ejector blade, characterized in that the ejector blade is rotatably attached to the brewing cylinder;wherein the brewing unit includes a shaft having an ejector lever and a locking element, wherein the at least one electric motor of the drive device is adapted to rotate the shaft in a first direction of rotation and in a second direction of rotation opposite to the first direction, wherein the ejector lever is adapted to transmit a force to the ejection device by a rotational movement of the shaft in the first direction of rotation, so that the ejector blade of the ejection device is moved over the brewing sieve surface of the lower brewing piston; 2. Brewing unit according to claim 1, characterized in that the locking element i) is suitable for fixing the lower brewing piston to the shaft by moving the shaft in the first direction of rotation; and / or ii) is suitable for releasing the lower brewing piston from the shaft by moving the shaft in the second direction of rotation; and / or iii) contains or consists of a locking hook which is preferably suitable for hooking the lower brewing piston to the shaft by moving the shaft in the first direction of rotation and for unhooking the lower brewing piston from the shaft by moving the shaft in the second direction of rotation.

3. Brewing unit according to one of the preceding claims, characterized in that the ejection device has a mechanical coupling which is suitable for absorbing a force of the ejector lever which is generated by a movement of the shaft in a first direction and for moving the ejector scoop over the brewing sieve surface of the lower brewing piston, wherein the lower brewing piston preferably has a planar brewing sieve surface and the mechanical coupling is suitable for absorbing a force of the ejector lever which is generated by a movement of the shaft in the first direction of rotation and for moving the ejector scoop in a linear direction over the brewing sieve surface of the lower brewing piston.

4. Brewing unit according to one of the preceding claims, characterized in that the brewing unit, preferably the ejection device, particularly preferably a mechanical coupling of the ejection device, has a substantially L-shaped structural element which has a shorter and a longer section and is rotatably fastened to the brewing cylinder at the intersection point of the shorter and longer section, wherein the longer section of the L-shaped structural element is further rotatably fastened to the ejector blade, and wherein the L-shaped structural element is preferably suitable i) by a rotational movement of the L-shaped structural element in a first rotational direction, the ejector blade, preferably in a linear ejection direction, over the brewing sieve surface of the lower brewing piston, wherein in particular the ejector lever of the shaft of the coffee machine is suitable, by rotating the shaft in the first direction of rotation of the shaft, to exert a force on the longer section of the L-shaped structural element and to cause a rotational movement of the L-shaped structural element in the first direction of rotation of the L-shaped structural element;and ii) by a rotational movement of the L-shaped structural element in a second direction of rotation, which is opposite to the first direction, to move the ejector blade in a preferably linear, retraction direction, which is opposite to the ejection direction, over the brewing sieve surface of the lower brewing piston, wherein in particular the ejector lever of the shaft of the coffee machine is suitable, by remaining in the ejection position and a movement of the brewing cylinder in a direction towards the upper brewing piston, to exert a force on the shorter section of the L-shaped structural element and to effect the rotational movement of the L-shaped structural element in the second direction of rotation of the L-shaped structural element.

5. Brewing unit according to one of the preceding claims, characterized in that the brewing cylinder is connected to the brewing unit via an element for reversibly receiving the brewing cylinder, wherein the element is preferably suitable for establishing a reversible connection between the brewing cylinder and the element, which is selected from the group consisting of locking pin closure, bayonet closure and combinations thereof.

6. Brewing unit according to one of the preceding claims, characterized in that the at least one electric motor of the drive device is suitable for rotating the shaft directly or via a coupling to the shaft, wherein the coupling is 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.

7. Brewing unit according to one of the preceding claims, characterized in that the brewing unit has a carriage which contains the upper brewing piston, optionally also contains a funnel, and the at least one electric motor of the drive device has a coupling to the carriage of the brewing unit, wherein the coupling preferably contains or consists of a stepping gear, preferably an intermittent stepping gear, and / or contains or consists of at least one gear wheel, at least one rack, at least one toothed belt and / or at least one chain.

8. Brewing unit according to one of the preceding claims, characterized in that the at least one electric motor of the drive device has a coupling to the brewing cylinder, wherein the coupling preferably contains a drive spindle and / or spindle nut.

9. Brewing unit according to one of the preceding claims, characterized in that the drive device has at least one second electric motor, wherein the at least one second electric motor of the drive device is suitable for moving the brewing cylinder in a first direction towards the upper brewing piston and in a second direction which is opposite to the first direction, wherein the at least one second electric motor preferably has a coupling to the brewing cylinder, wherein the coupling preferably contains at least one drive spindle.

10. Coffee machine comprising a) a brewing unit according to one of the preceding claims; b) a grounds container with an interior for receiving brewed coffee grounds cake, wherein the grounds container is arranged below the brewing cylinder and wherein a wall of the interior of the grounds container has a certain distance from the brewing cylinder in an ejection direction for coffee grounds cake; and c) contains a control unit configured to control or regulate the brewing unit of the coffee machine.

11. Coffee machine according to claim 10, characterized in that the control unit is configured to cause the drive device to rotate the shaft i) in the first direction of rotation in order to fix the locking element of the shaft to the lower brewing piston and to move the ejector lever of the shaft towards a mechanical coupling of the ejection device, preferably towards a substantially L-shaped structural element of the brewing cylinder, particularly preferably when the control unit receives or generates a signal to eject a coffee grounds cake;and / or ii) to rotate in the second direction of rotation, which is opposite to the first direction, in order to release the locking element of the shaft on the lower brewing piston and to move the ejector lever of the shaft away from a mechanical coupling of the ejection device, preferably away from a substantially L-shaped structural element of the brewing cylinder, particularly preferably when the control unit receives or generates a signal to brew coffee.; 12. Coffee machine according to one of claims 10 or 11, characterized in that the control unit is configured to cause the at least one electric motor of the drive device, or at least a second electric motor of the coffee machine, to move the brewing cylinder i) to move in a direction toward the upper brewing piston, preferably when the control unit receives or generates a signal to brew coffee; and / or ii) to move 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.

13. Coffee machine according to one of the preceding claims 10 to 12, characterized in that the control unit is configured to control an electrical power of the drive device which is used to rotate the shaft, preferably via an electrical voltage, particularly preferably via a pulsed electrical voltage, wherein the control is carried out in particular via a pulse width modulation.

14. Coffee machine according to one of claims 10 to 13, characterized in that the control unit is configured to change an electrical power of the drive device used to rotate the shaft after a predetermined number of brewing cycles, wherein the control unit is preferably configured to reduce an electrical power of the drive device used to rotate the shaft from a first electrical power to a second electrical power i), preferably in such a way that a coffee grounds cake transported by the second electrical power is transported to a location in the interior of the grounds container that is closer to the brewing cylinder than the location to which at least one coffee grounds cake was transported by means of the first electrical power, wherein the first electrical power is optionally a maximum electrical power;and / or ii) to increase, preferably in such a way that a coffee grounds cake conveyed by the second electrical power is conveyed to a location in the interior of the grounds container which is further away from the; The brewing cylinder is the location to which at least one coffee grounds cake was transported using the first electrical power, where the first electrical power is optionally a minimum electrical power.

15. Coffee machine according to one of claims 10 to 14, characterized in that the control unit is configured to change an electrical power of the drive device which is used to rotate the shaft in such a way that i) the ejection device conveys a first layer of coffee grounds cakes arranged next to one another into the interior of the grounds container, wherein the control unit is particularly preferably configured to subsequently convey at least one further layer, preferably a plurality of layers, of coffee grounds cakes into the interior of the grounds container in this way, in particular until the interior of the grounds container is completely filled with coffee grounds cakes;or ii) after brewing a total quantity of dry coffee powder corresponding to 25% to 75% of the capacity of the grounds container of the coffee machine for a total quantity of dry coffee powder, further coffee grounds cakes are transported to a location in the interior of the grounds container which is closer to the brewing cylinder than the location to which the coffee grounds cakes were transported by means of electrical power before they were changed;

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