COFFEE GRINDER, COFFEE MACHINE AND METHOD FOR GRINDING COFFEE IN A COFFEE GRINDER

Description

[0001] A coffee grinder, a coffee machine, and a method for grinding coffee in a coffee grinder are provided. The coffee grinder is characterized by its two-part housing, which ensures maximum stability in a minimal installation space. Furthermore, the coffee grinder features a DC motor. This motor allows the grinder to produce ground coffee with maximum durability and without significant operational delays (e.g., due to clogged coffee grounds) in the smallest possible space. The coffee grinder can be used in a coffee machine. Additionally, the coffee grinder and / or the coffee machine can be used in a coffee grinding process, offering the same advantages to both.

[0002] Coffee grinders for fully automatic or semi-automatic coffee machines consist of a multi-part housing, an attached bean hopper, and a drive mechanism consisting of an AC or DC motor. Conical burr grinders or grinding discs are typically used to grind the coffee beans. For high demands on grinding performance and grind size, grinders with grinding discs are generally used. In this type of grinder, the coffee beans are ground between two grinding discs located within the grinder's housing. One of the two discs is stationary, while the other rotates. The grind size (coarser / finer) is adjusted by changing the distance between the two discs. Standard, commercially available motors, coupled to the grinder mechanism, are typically used as the drive mechanism.

[0003] Coffee grinder manufacturers often source the motors for their grinders from third-party suppliers. This has the disadvantage that if the third-party supplier changes the motors (e.g., their dimensions), the grinder housing must also be adapted by the coffee grinder manufacturer, potentially requiring additional components. This translates into significant time and expense for the coffee grinder manufacturer.

[0004] Many coffee grinders are currently powered by AC motors. While these have the advantage of being directly powered by the mains without putting a strain on the coffee machine's power supply, AC motors have the disadvantage of relatively low starting torque. To ensure grinding even relatively hard coffee beans, AC motors must therefore be significantly oversized, meaning they are relatively large and require considerable space within the coffee grinder. Another disadvantage of AC motors is their poor efficiency; they generate a high degree of heat and thermal expansion during operation.

[0005] One advantage of conventional DC motors is that they don't need to be oversized like AC motors, as they develop high torque right from the start and can be operated with overloads. However, the disadvantage is that the power supply for DC motors must be correspondingly large to deliver the high starting currents required. Furthermore, operating with very high starting currents under overload reduces the lifespan of the DC motors. Conventional DC motors also suffer from poor speed stability and lack the ability to monitor their speed. Additionally, conventional DC motors typically exhibit low efficiency because high motor speeds necessitate the use of a gearbox. Another disadvantage is that their speed is load-dependent.When using such motors in a coffee grinder, this means that the amount of ground coffee depends on the fill level of the bean container and also on the type of bean.

[0006] US 10,405,700 B2 discloses a mill comprising a receiving hopper formed from a receiving chamber and an installation chamber, wherein an electric drive device is arranged in the installation chamber and a hollow grinding chamber is arranged at the lower end of the receiving hopper. The interior of the hollow grinding chamber contains a support element provided with a rotating shaft and a passive rod connected to a first conical grinding disc. The upper end of the passive rod is connected to an output shaft of the mill and the lower end of the passive rod is connected to the rotating shaft of the mill, allowing the conical grinding disc to project into the grinding seat and creating a gap between the conical grinding disc and the grinding seat.

[0007] EP 3 669 723 A1 discloses an electric coffee grinder comprising a container for holding the coffee beans to be ground and a first grinding disc and a second grinding disc for grinding coffee beans, wherein the first grinding disc is attached to the container for holding the coffee beans to be ground and the second grinding disc is connected to the container without the interposition of reduction gears and / or gears.

[0008] is connected to the output shaft of an electric motor.

[0009] Based on this, the object of the present invention was to provide a coffee grinder, a coffee machine, and a method for grinding coffee in a coffee grinder, which no longer exhibits at least one of the disadvantages known in the prior art. In particular, the coffee grinder, the coffee machine, and the method should allow ground coffee to be provided with maximum durability and without prolonged operational delays (e.g., due to clogged coffee grounds) in the smallest possible installation space. Preferably, the coffee grinder, the coffee machine, and the method should also allow ground coffee to be provided with high quality, minimal power consumption, minimal noise, and / or constant dispensing capacity.

[0010] The problem is solved by the coffee grinder with the features of claim 1, the coffee machine with the features of claim 12, and the method with the features of claim 14. The dependent claims describe advantageous embodiments.

[0011] According to the invention, a coffee grinder is provided with a two-part housing, containing a) a housing upper part with an interior suitable for holding coffee beans; b) a housing lower part connected to the housing upper part and having an interior suitable for holding a DC motor (preferably a brushless DC motor); c) a grinding disc assembly comprising or consisting of a first, upper, non-rotating grinding disc and a second, lower, rotating grinding disc, wherein the first grinding disc is arranged opposite the second grinding disc and the coffee grinder is capable of changing the distance between the first grinding disc and the second grinding disc;and d) a DC motor (preferably a brushless DC motor) comprising a stator, a rotor and a motor shaft, wherein the motor shaft is connected to the rotor and to the second grinding disc, wherein the stator and rotor are arranged within the interior of the lower housing part and the motor shaft is arranged within the lower housing part and at least partially within the upper housing part; ; wherein the coffee grinder is suitable for rotating the second grinding disc by a movement of the rotor of the DC motor relative to the first grinding disc, characterized in that the DC motor is a housingless DC motor.

[0012] The coffee grinder according to the invention is suitable for providing ground coffee with maximum service life and without prolonged operational delay (e.g. due to clogged coffee grounds) in the smallest possible installation space.

[0013] The reason for this is that the grinder housing consists of only two parts, thus requiring fewer components and connecting elements, resulting in a smaller design and greater long-term stability. Positioning the DC motor within the grinder housing (specifically, in the lower part) further reduces the required installation space. Furthermore, the speed of DC motors is controllable and, if equipped with a rotation angle sensor, even adjustable. Among other things, DC motors allow for clockwise and counterclockwise rotation, which makes it possible to quickly free grinding discs that become stuck due to coffee residue during operation and resume grinding. This prevents extended downtime caused by clogged coffee grounds and can extend the lifespan of the coffee grinder.

[0014] If a brushless DC motor is used, the coffee grinder is also suitable for producing high-quality ground coffee with minimal power consumption, minimal noise, an even longer lifespan, consistent dosing performance, and in an even smaller footprint. Unlike conventional DC motors, this motor does not use carbon brushes but is electronically commutated, resulting in lower susceptibility to wear and quieter operation. Furthermore, brushless DC motors are significantly more energy-efficient than conventional DC motors and, for the same power output as conventional DC or AC motors, require less installation space (due to the absence of carbon brushes). Brushless DC motors also generate less heat than conventional DC motors, which helps ensure high-quality ground coffee.Furthermore, brushless DC motors inherently feature a rotation angle sensor that can be used to control their speed. This allows, for example, a potential drop in speed under high load to be quickly corrected (i.e., compensated for by increasing the motor power), thus ensuring a constant dosing rate.

[0015] The upper housing part of the coffee grinder can be connected to the lower housing part by a reversible connection. The reversible connection is preferably selected from the group consisting of friction-fit connections, positive-lock connections, and combinations thereof. Particularly preferred is the reversible connection selected from the group consisting of clamp connections, screw connections, clip connections, snap-hook connections, connections via a grooved surface, and combinations thereof. In particular, the reversible connection is a screw-clamp connection via a clamping ring. The advantage of this connection via a clamping ring is that the upper housing part can be rotated 360° relative to the lower housing part. This allows the outlet of the coffee grinder for the ground coffee (e.g., a through-opening in the upper housing part of the coffee grinder) to be flexibly rotated in a desired direction, even when the coffee grinder is fully assembled.This can be advantageous, for example, if a coffee machine has two coffee grinders according to the invention and the outlet for ground coffee for both grinders needs to be adjusted to an inlet of a brewing unit of the coffee machine. This adjustment can thus be carried out more quickly and easily.

[0016] The coffee grinder can have a through opening from an interior space to an exterior space and be designed to convey ground coffee through this opening (i.e., the coffee grinder can have an outlet for ground coffee). The through opening is preferably located in the upper part of the housing. Furthermore, the through opening is preferably connected to a conduit, the conduit optionally being connected to the upper part of the housing by a connection selected from the group consisting of a push-fit connection, a screw connection, and combinations thereof. The conduit can simplify adjusting or directing the outlet of ground coffee into an inlet of a brewing unit of a coffee machine or into a portafilter for a coffee machine.

[0017] The coffee grinder may have a bearing element in the lower part of the housing for supporting the motor shaft.

[0018] The bearing element preferably has an external thread by which it is screwed to the lower part of the housing, wherein the external thread particularly preferably has a pitch in the range of 0.2 mm to 1.0 mm, more preferably 0.3 mm to 0.8 mm, and most preferably 0.4 mm to 0.6 mm, particularly 0.5 mm. A pitch in this range has proven advantageous for fine adjustment of the distance between the second and first grinding discs, i.e., for fine adjustment of the grind size.

[0019] In an advantageous embodiment, the bearing element is connected to an adjustment motor, preferably via a gear that engages with a pinion of the adjustment motor. The adjustment motor is particularly suitable for changing the position of the bearing element and the motor shaft mounted therein in the direction of the longitudinal axis of the motor shaft. The adjustment motor can optionally be enclosed by the coffee grinder or by a coffee machine that incorporates the coffee grinder according to the invention. Alternatively, in principle, it is conceivable that the position of the bearing element and the motor shaft mounted therein in the direction of the longitudinal axis of the motor shaft can be changed without the aid of a user, for example, by manually rotating the bearing element.

[0020] The motor shaft of the DC motor is preferably suited to changing its position along its longitudinal axis. Since the motor shaft is connected to the second grinding disc, this suitability for changing position along the longitudinal axis offers the advantage that the distance between the second grinding disc and the first grinding disc (and thus the grind of the coffee beans) can be adjusted via axial movement of the motor shaft. To enable this, the motor shaft is preferably connected to a bearing element for supporting the motor shaft, preferably in a region of the motor shaft located in the lower part of the housing. An adjustment motor of the coffee grinder, or an adjustment motor of a coffee machine incorporating the coffee grinder, is suitable for changing the position of the bearing element and the motor shaft supported therein along the longitudinal axis of the motor shaft by rotating its rotor.

[0021] Furthermore, the motor shaft can be connected to the rotor of the DC motor in a region of the motor shaft that is located in the lower part of the housing, wherein the DC motor is suitable for causing a rotational movement of the motor shaft about the longitudinal axis of the motor shaft by means of a rotation of its rotor.

[0022] Apart from this, the motor shaft can be connected to the second (i.e., the lower, rotatable) grinding disc via a grinding disc carrier, particularly preferably in a section of the motor shaft located within the upper part of the housing. Connecting the motor shaft to the second grinding disc via a grinding disc carrier has the advantage of establishing a power-transmitting connection between the motor shaft and the second grinding disc in a simpler and more cost-effective manner. For example, when replacing the second grinding disc, there is no need to adjust the grinding disc to the motor shaft geometry. Furthermore, the relatively direct connection of the second grinding disc to the motor shaft via the grinding disc carrier improves the concentricity and flatness of the second grinding disc compared to coffee grinders with multiple adapters and drive components.Improving the concentricity and flatness of the grinding process can ensure a consistent grind size during operation of the coffee grinder.

[0023] The first grinding disc and / or the second grinding disc may contain or consist of a material selected from the group consisting of metal, ceramic and combinations thereof, preferably a material selected from the group consisting of steel, ceramic and combinations thereof, in particular a material selected from the group consisting of X210CrW12 steel and Al 2 O 3 ceramic.

[0024] Furthermore, the first grinding disc and / or second grinding disc can have an outer diameter in the range of 30 to 80 cm, preferably 55 to 70 cm, in particular 65 cm.

[0025] Furthermore, the first grinding disc and / or second grinding disc may be located in the upper part of the housing.

[0026] The coffee grinder can have a feed element (for coffee) located in the upper part of the housing. The feed element can have a spindle with a spindle axis. Preferably, the feed element is designed to rotate (about its spindle axis) and thereby transport coffee beans to the grinding disc assembly. The advantage of this is a uniform feed of coffee beans into the grinding disc assembly, which ensures a more consistent grinding result (e.g., with regard to the amount of coffee ground and / or the grind size). The feed element can have a safety guard designed to prevent reaching into the interior of the upper part of the housing. This prevents potential injuries to a user of the coffee grinder. The feed element is preferably connected to the second, lower, rotatable grinding disc. This allows the rotation of the feed element to be caused by the rotation of the second grinding disc.The feed element can rotate together with the second grinding disc. Preferably, the feed element is screwed to the motor shaft (and the second, lower, rotatable grinding disc).

[0027] The second, lower, rotating grinding disc can be a single piece with the grinding disc carrier. In this case, replacing the second grinding disc would also require replacing the grinding disc carrier.

[0028] In an advantageous embodiment, the second, lower, rotatable grinding disc is connected to a grinding disc carrier, preferably via a connection selected from the group consisting of frictional connections, positive-lock connections, and combinations thereof, wherein the connection is particularly a screw connection. The advantage of this embodiment is that when the second grinding disc is replaced, the grinding disc carrier does not need to be replaced, which saves material and costs and is therefore more economical and environmentally friendly.

[0029] The DC motor can be either a brushed or a brushless DC motor. The advantage of a brushless DC motor is that it already has a built-in angle sensor. This sensor can be used to regulate its speed, ensuring a consistent dispensing rate from the coffee grinder. Furthermore, due to the absence of carbon brushes, a brushless DC motor generates less heat during operation than a conventional DC motor, resulting in higher-quality ground coffee. The absence of carbon brushes also means a lower current draw and a longer lifespan (since there are no friction losses from the brushes). Additionally, the brushless DC motor allows for quieter operation (as there is no noise from rubbing carbon brushes) and a more compact design for the coffee grinder (since no carbon brushes take up space).

[0030] According to the invention, the DC motor is a housingless DC motor, optionally a housingless brushed DC motor or a housingless brushless DC motor. An advantage of the housingless DC motor is that a coffee grinder manufacturer who sources the housingless (optionally brushless) DC motor from a third-party manufacturer is no longer dependent on the motor housing design specified by the third-party supplier and subject to change. This increases the coffee grinder manufacturer's flexibility and reduces production costs. Furthermore, a housingless (optionally brushless) DC motor requires less installation space than a (optionally brushless) DC motor with a housing, which can further reduce the installation space required for the coffee grinder.This is because, in this embodiment, the lower housing part (and at least partially the upper housing part) of the coffee grinder according to the invention can represent the (only) housing of the housingless DC motor.

[0031] The DC motor can have a power consumption in the range of 50 to 500 watts. A power consumption in this range has proven advantageous for grinding coffee.

[0032] In a preferred embodiment, the DC motor has a height in the range of 25 to 70 mm, particularly preferably 35 to 45 mm, especially 40 mm, and / or a diameter in the range of 50 to 120 mm. These dimensions allow for the provision of a very compact coffee grinder.

[0033] The coffee grinder, preferably its DC motor, may include a control unit. The control unit is preferably configured to control or regulate the speed of the DC motor. Furthermore, the control unit may be configured to control or regulate the direction of rotation of the DC motor's rotor. For this control function, the DC motor must have a rotation angle sensor.

[0034] In a preferred embodiment, the DC motor thus includes a rotary angle sensor, wherein the rotary angle sensor is preferably selected from the group consisting of optical rotary angle sensors, magnetic rotary angle sensors, and combinations thereof, wherein the rotary angle sensor particularly preferably includes or consists of a Hall sensor and / or GMR sensor. The rotary angle sensor has the advantage that the speed of the DC motor can be controlled, thereby quickly compensating for any potential drop in speed due to a high load and thus ensuring that the coffee grinder maintains a constant dosing performance.

[0035] Preferably, a control unit of the coffee grinder, preferably a control unit of the DC motor of the coffee grinder, is configured to regulate the speed of the DC motor based on at least one signal from the rotary angle sensor.

[0036] Furthermore, it is preferred that a control unit of the coffee grinder, preferably a control unit of the DC motor of the coffee grinder, is configured to control or regulate the direction of rotation of the rotor of the DC motor based on at least one signal from the rotation angle sensor. By regulating the direction of rotation, it is possible to resolve a potential blockage of the first and second grinding discs by coffee beans or coffee grounds (i.e., a potential blockage of the grinding mechanism), so that the operation of the coffee grinder can continue.

[0037] It is therefore preferred that a control unit of the coffee grinder, preferably a control unit of the DC motor of the coffee grinder, is configured to detect a blockage of the DC motor based on at least one signal from the rotation angle sensor and, in the event of a detected blockage, to reverse the direction of rotation of the DC motor for a certain period of time, in particular 1 to 5 seconds, and / or for a certain degree of revolutions, in particular 0.25 to 10 revolutions.

[0038] In a further preferred embodiment, a control unit of the coffee grinder, preferably a control unit of the DC motor of the coffee grinder, is configured to detect a contact point of the first grinding disc on the second grinding disc based on at least one signal from the rotation angle sensor and, in the event of a detected contact point, to define this as a setting for the finest grind of the coffee grinder. For the detection of the contact point, in addition to the at least one signal from the rotation angle sensor, the current draw of the DC motor is preferably also taken into account, wherein a contact point is optionally detected either by a drop in rotational speed at a constant current draw or by an increase in current draw at a constant rotational speed.

[0039] The upper and / or lower housing of the coffee grinder may have a wall thickness of 1 to 5 mm in at least some areas.

[0040] Furthermore, the upper housing part and / or the lower housing part of the coffee grinder may contain or consist of a material selected from the group consisting of metal, plastic and combinations thereof, preferably a material selected from the group consisting of die-cast aluminum, die-cast zinc, steel, plastic and combinations thereof.

[0041] Furthermore, the upper housing part and / or the lower housing part of the coffee grinder may have a height in the range of 50 to 150 mm.

[0042] Apart from that, the upper housing part and / or the lower housing part of the coffee grinder can have a diameter in the range of 50 to 150 mm.

[0043] Furthermore, the upper part and / or the lower part of the coffee grinder housing may have a hollow cylinder shape, at least in some areas.

[0044] A sensor element for detecting the grind size can be arranged at the base of the lower housing part of the coffee grinder. This sensor element is suitable for detecting the distance between the sensor element and a bearing element for supporting the motor shaft of the DC motor. A control unit of the coffee grinder according to the invention, or of a coffee machine incorporating the coffee grinder according to the invention, can be configured to determine the grind size of the coffee grinder (or the coffee) from information provided by the sensor element.

[0045] According to the invention, a coffee machine is further provided which includes a coffee grinder according to the invention. The coffee machine is preferably a semi-automatic coffee machine or a fully automatic coffee machine.

[0046] The DC motor of the coffee grinder of the coffee machine can have a rotary angle sensor, preferably a rotary angle sensor selected from the group consisting of optical rotary angle sensors, magnetic rotary angle sensors and combinations thereof, wherein the rotary angle sensor particularly preferably includes or consists of a Hall sensor and / or GMR sensor.

[0047] A control unit of the coffee grinder and / or the coffee machine can be configured to regulate the speed of the DC motor based on at least one signal from the rotary angle sensor.

[0048] Furthermore, a control unit of the coffee grinder and / or the coffee machine can be configured to regulate the direction of rotation of the rotor of the DC motor.

[0049] Furthermore, a control unit of the coffee grinder and / or the coffee machine can be configured to detect a blockage of the DC motor and, in the event of a detected blockage, to reverse the direction of rotation of the DC motor for a certain period of time, in particular 1 to 5 seconds, and / or for a certain degree of revolutions, in particular 0.25 to 10 revolutions.

[0050] Apart from that, a control unit of the coffee grinder and / or the coffee machine can be configured to detect a grinding point of the first grinding disc on the second grinding disc and, in the event of a detected grinding point, to set this as a setting for the finest grind of the coffee grinder, whereby, in addition to at least one signal from the rotation angle sensor, a current consumption of the DC motor is optionally taken into account for the detection of the grinding point, whereby a grinding point is optionally detected either by a drop in rotational speed at constant current consumption or by an increase in current consumption at constant rotational speed.

[0051] According to the invention, a method for grinding coffee in a coffee grinder is further provided, comprising the steps a) Providing a coffee grinder or coffee machine according to the invention; b) Filling the upper part of the housing of the coffee grinder with coffee beans or coarsely ground coffee; and c) Grinding the coffee beans or coarsely ground coffee.

[0052] In the method, the DC motor of the coffee grinder can have a rotary angle sensor, preferably a rotary angle sensor selected from the group consisting of optical rotary angle sensors, magnetic rotary angle sensors and combinations thereof, wherein the rotary angle sensor particularly preferably includes or consists of a Hall sensor and / or GMR sensor.

[0053] In this method, the speed of the DC motor can be controlled based on at least one signal from the rotary angle sensor.

[0054] Furthermore, the method allows the direction of rotation of the rotor of the DC motor to be controlled based on at least one signal from the rotation angle sensor.

[0055] Furthermore, in the method, based on at least one signal from the rotation angle sensor, a blockage of the DC motor can be detected and, in the event of a detected blockage, the direction of rotation of the DC motor can be reversed for a certain period of time, in particular 1 to 5 seconds, and / or for a certain degree of revolutions, in particular 0.25 to 10 revolutions.

[0056] Apart from that, in the method, based on at least one signal from the rotary angle sensor, a friction point of the first grinding disc on the second grinding disc can be detected and, in the case of a detected friction point, this can be set as a setting for the finest grind of the coffee grinder, whereby, in addition to the at least one signal from the rotary angle sensor, a current consumption of the DC motor is optionally taken into account for the detection of the friction point, whereby a friction point is optionally detected either by a drop in rotational speed at constant current consumption or by an increase in current consumption at constant rotational speed.

[0057] The above-mentioned process steps can be carried out by a control unit of the DC motor, by a control unit of the coffee grinder, or by a control unit of the coffee machine.

[0058] The following figures are intended to explain the subject matter of the invention in more detail, without limiting it to the specific embodiments shown here. Figure 1Figure 1 schematically shows the internal structure of a specific embodiment of a coffee grinder according to the invention. The coffee grinder comprises an upper housing part 1 with an interior space 2 suitable for holding coffee beans, and a lower housing part 3 connected to the upper housing part 1. In this embodiment, it can be seen that the upper housing part 1 is connected to the lower housing part 3 by a screw-clamp connection 11 via a clamping ring 12. The clamping ring 12 allows the upper housing part 1 to rotate 360° relative to the lower housing part 3. The arrangement of the feed element 21 with its anti-entry guard 22 is also shown. The feed element 21 serves to feed coffee (beans) and secures the first grinding disc 5 in the upper housing part 1 of the coffee grinder.The access guard prevents a user from accidentally reaching into the interior 2 of the housing top 1 and can thus prevent potential injuries to the user. The housing top 1 has a through opening that is connected to a conduit 14. The conduit 14 is attached to the housing top 1 via a screw connection 15. Figure 2 schematically shows a cross-section through a specific embodiment of a coffee grinder according to the invention and shows, in addition to the features described in Figure 1In addition to the illustrated parts of the coffee grinder, further parts of the coffee grinder are shown. For example, the interior 4 of the lower housing 3 of the coffee grinder is shown in more detail. It can be seen that the coffee grinder contains a grinding disc assembly consisting of a first, upper, non-rotating grinding disc 5 and a second, lower, rotatable grinding disc 6, with the first grinding disc 5 positioned opposite the second grinding disc 6. The coffee grinder is designed to change the distance between the first grinding disc 5 and the second grinding disc 6. Furthermore, the coffee grinder includes a brushless DC motor having a stator 8 and a rotor 9, the rotor 9 being connected to the second grinding disc 6. The coffee grinder is designed to rotate the second grinding disc 6 relative to the first grinding disc 5 by a movement of the rotor 9 of the brushless DC motor, which is transmitted to the motor shaft 10.Furthermore, it is visible that the motor shaft 10 is connected to a bearing element 16 for supporting the motor shaft 10 via a press fit. The bearing element 16 has an external thread 17 through which it is screwed to the lower housing part 3. The bearing element 16 is also connected to a gear 19, which engages with a pinion (not shown) of an adjustment motor 18. The adjustment motor 18 allows the bearing element 16, and thus the motor shaft 10, to be moved in one direction along the longitudinal axis of the motor shaft 10. This movement allows the second grinding disc 6, which is connected to the motor shaft 10 via a grinding disc carrier, to be moved towards and away from the first grinding disc (i.e., the grind of the coffee to be changed). In this embodiment, a sensor element 25 for detecting the grind is arranged on the bottom of the lower housing part 3. This sensor element is suitable for detecting a distance between the sensor element 25 and the bearing element 16.From this distance information, a grind setting for the coffee grinder (or the coffee) can be derived. Figure 3 schematically shows individual parts of a specific embodiment of a coffee grinder according to the invention and their assembly into a complete coffee grinder. Figures 4A and 4B Figure 1 shows a connection between the upper housing part 1 and the lower housing part 3 via a clamping ring 12 for a specific embodiment of a coffee grinder according to the invention. Figure 4B The figure shows that the clamping ring 12 fastens the upper housing part 1 to the lower housing part 3 via a screw connection 11. The advantage of the clamping ring 12 is that the upper housing part 1 can be rotated 360° relative to the lower housing part, allowing an outlet for ground coffee located on the upper housing part to be easily and flexibly repositioned as needed. Reference symbol list

[0059] 1: Upper housing part; 2: Interior of upper housing part; 3: Lower housing part (or part thereof); 4: Interior of lower housing part; 5: First, upper, non-rotating grinding disc; 6: Second, lower, rotating grinding disc; 7: Brushless DC motor; 8: Stator of the brushless DC motor; 9: Rotor of the brushless DC motor; 10: Motor shaft of the brushless DC motor; 11: Screw connection; 12: Clamping ring; 13: Through opening; 14: Conduit; 15: Screw connection; 16: Bearing element for supporting the motor shaft; 17: External thread of the bearing element for supporting the motor shaft; 18: Adjustment motor (e.g., of the coffee grinder itself); 19: Gear; 20: Grinding disc carrier (for supporting the second, lower, rotatable grinding disc); 21: Feed element; 22: Gripping guard on the feed element; 23: Upper motor bearing; 24: Lower motor bearing; 25: Sensor element for detecting the grinding degree.

Claims

1. A coffee grinder with a two-part housing, comprising a) a housing upper part (1) with an interior space (2) which is suitable for accommodating coffee beans; b) a housing lower part (3), which is connected to the housing upper part (1) and has an interior space (4) suitable for accommodating a DC motor (7); c) a grinding disc assembly, which comprises a first, upper, non-rotatable grinding disc (5) and a second, lower, rotatable grinding disc (6), the first grinding disc (5) being positioned opposite the second grinding disc (6), and the coffee grinder being suitable for changing a distance between the first grinding disc (5) and the second grinding disc (6); and d) a DC motor (7), which comprises a stator (8), a rotor (9) and a motor shaft (10), the motor shaft (10) being connected to the rotor (9) and to the second grinding disc (6), the stator (8) and rotor (9) being positioned within the interior space (4) of the housing lower part (3), and the motor shaft (10) being positioned within the housing lower part (3) and at least partially within the housing upper part (1); the coffee grinder being suitable to rotate the second grinding disc (6) relative to the first grinding disc (5) by a movement of the rotor (9) of the DC motor (7), characterised in that the DC motor (7) is a frameless DC motor (7).

2. The coffee grinder according to the preceding claim, characterised in that the housing upper part (1) is connected by a reversible connection to the housing lower part (3), the reversible connection preferably being selected from the group consisting of a frictional connection, form-fit connection and combinations thereof, the reversible connection being particularly preferably selected from the group consisting of a clamping connection, a screwed joint (11), a clamp connection, a snap hook connection, a connection via a ribbed surface and combinations thereof, the reversible connection particularly being a threaded-clamp connection via a clamping ring (12).

3. The coffee grinder according to any one of the preceding claims, characterised in that the coffee grinder has a through hole (13) from an interior space of the coffee grinder to an exterior space of the coffee grinder and is suitable for conveying ground coffee through the through hole (13), the through hole (13) being preferably i) positioned in the housing upper part (1); and / or ii) connected to a conduit (14), the conduit (14) being optionally connected to the housing upper part (1) via a connection selected from the group consisting of a plug connection, a screwed joint (15) and combinations thereof; screwed on.

4. The coffee grinder according to any one of the preceding claims, characterised in that the coffee grinder has a bearing member (16) in the housing lower part (3) to support the motor shaft (10), the bearing member (16) preferably i) having an external thread (17) by means of which it is screwed to the housing lower part (3), the external thread (17) having a pitch in the range of 0.2 mm to 1.0 mm, particularly preferably 0.3 mm to 0.8 mm, most preferably 0.4 mm to 0.6 mm, particularly 0.5 mm; and / or ii) being connected to a variable displacement motor (18), preferably via a gear wheel (19) that meshes with a pinion of the variable displacement motor (18), the variable displacement motor (18) being particularly suitable for changing a position of the bearing member (16) and the motor shaft (10) supported therein in the direction of the longitudinal axis of the motor shaft (10), the variable displacement motor (18) being optionally comprised by the coffee grinder or comprised by a coffee machine which comoprises the coffee grinder.

5. The coffee grinder according to any one of the preceding claims, characterised in that the motor shaft (10) of the DC motor (7) is suitable for changing a position of the motor shaft (10) in the direction of the longitudinal axis, the motor shaft (10) being preferably i) connected to a bearing member (16) for supporting the motor shaft (10), preferably in a region of the motor shaft (10) which is positioned in the housing lower part (3), a variable displacement motor (18) of the coffee grinder or a variable displacement motor (18) of a coffee machine which comprises the coffee grinder being suitable for causing a change in the position of the bearing member (16) and the motor shaft (10) supported therein in the direction of the longitudinal axis of the motor shaft (10) via a rotation of its rotor (9); and / or ii) connected with the rotor (9) of the DC motor (7) in a region of the motor shaft (10) which is positioned in the housing lower part (3), the DC motor (7) being suitable for causing a rotary movement of the motor shaft (10) around the longitudinal axis of the motor shaft (10) via a rotation of its rotor (9); and / or iii) connected to the second, lower, rotatable grinding disc via a grinding disc carrier (20), particularly preferably in a region of the motor shaft (10) which is positioned inside the housing upper part (1).

6. The coffee grinder according to one of the preceding claims, characterised in that the first grinding disc (5) and / or the second grinding disc (6) i) comprises or consists of a material selected from the group consisting of metal, ceramics and combinations thereof, preferably a material selected from the group consisting of steel, ceramics and combinations thereof, particularly a material selected from the group consisting of X210CrW12 steel and Al2O3 ceramics; and / or ii) has an outer diameter in the range of 30 to 80 cm, preferably 55 to 70 cm, particularly 65 cm; and / or iii) is positioned in the housing upper part (1).

7. The coffee grinder according to any one of the preceding claims, characterised in that the second grinding disc (6) i) is monolithic with a grinding disc carrier (20); or ii) is connected to a grinding disc carrier (20), preferably via a connection selected from the group consisting of a frictional connection, a form-fit connection and combinations thereof, the connection being in particular a screw connection.

8. The coffee grinder according to one of the preceding claims, characterised in that the DC motor (7) i) is a frameless, brushed DC motor (7) or a frameless, brushless DC motor (7); and / or ii) has a power consumption in the range of 50 to 500 watts; and / or iii) has a height in the range of 25 to 70 mm, particularly preferably 35 to 45 mm, particularly preferably 40 mm; and / or iv) has a diameter in the range of 50 to 120 mm.

9. The coffee grinder according to any one of the preceding claims, characterised in that the coffee grinder, preferably the DC motor (7) of the coffee grinder, has a controller which is preferably configured i) to control or regulate a rotational speed of the DC motor (7); and / or ii) to control or regulate a rotational direction of the rotor (9) of the DC motor (7).

10. The coffee grinder according to the preceding claim, characterised in that the DC motor (7) has a rotation angle sensor, the rotation angle sensor being preferably selected from the group consisting of an optical rotation angle sensor, a magnetic rotation angle sensor and combinations thereof, the rotation angle sensor particularly preferably comprising or consisting of a Hall sensor and / or a GMR sensor, and a control unit of the coffee grinder, preferably a control unit of the DC motor (7) of the coffee grinder, being preferably configured, based on at least one signal from the rotation angle sensor, i) to regulate a rotational speed of the DC motor (7); and / or ii) to control or regulate a rotational direction of the rotor (9) of the DC motor (7); and / or iii) to detect a blockage of the DC motor (7) and, in the event a blockage is detected, to reverse the rotational direction of the DC motor (7) for a specific period of time, particularly 1 to 5 seconds, and / or for a specific number of revolutions, in particular 0.25 to 10 revolutions; and / or iv) to detect a grinding point of the first grinding disc (5) on the second grinding disc (6) and, in the event of a detected grinding point, to set this as an adjustment for the finest grind of the coffee grinder, wherein, to detect the grinding point, the current consumption of the DC motor (7) being preferably also taken into account in addition to the at least one signal from the rotation angle sensor, a grinding point being optionally detected either by a drop in the rotational speed at a constant current consumption or by an increase in current consumption at a constant rotational speed.

11. The coffee grinder according to the preceding claim, characterised in that the housing upper part (1) and / or the housing lower part (3) i) at least has a wall thickness in the range of 1 mm to 5 mm; and / or ii) comprises or consists of a material selected from the group consisting of metal, plastic and combinations thereof, preferably a material selected from the group consisting of die-cast aluminium, die-cast zinc, steel, plastic and combinations thereof; and / or iii) has a height in the range of 50 to 150 mm; and / or iv) has a diameter in the range of 50 to 150 mm; and / or v) is at least in part shaped as a hollow cylinder.

12. A coffee machine, comprising a coffee grinder according to any one of the preceding claims, the coffee machine being preferably a semi-automatic coffee machine or a fully automatic coffee machine.

13. The coffee grinder according to claim 12, characterised in that the DC motor (7) of the coffee grinder of the coffee machine has a rotation angle sensor, preferably a rotation angle sensor selected from the group consisting of an optical rotation angle sensor, a magnetic rotation angle sensor and combinations thereof, the rotation angle sensor particularly preferably comprising or consisting of a Hall sensor and / or a GMR sensor, and a controller of the coffee grinder and / or the coffee machine being configured, based on at least one signal from the rotation angle sensor, i) to regulate a rotational speed of the DC motor (7); and / or ii) to regulate a rotational direction of the rotor (9) of the DC motor (7); and / or iii) to detect a blockage of the DC motor (7) and, in the event a blockage is detected, to reverse the rotational direction of the DC motor (7) for a specific period of time, particularly 1 to 5 seconds, and / or for a specific number of revolutions, in particular 0.25 to 10 revolutions; and / or iv) to detect a grinding point of the first grinding disc (5) on the second grinding disc (6) and, in the event of detecting grinding point, setting this as an adjustment for the finest grind of the coffee grinder, wherein, to detect the grinding point, the current consumption of the DC motor (7) being optionally also taken into account in addition to the at least one signal from the rotation angle sensor, a grinding point being optionally detected either by a drop in rotational speed at constant current consumption or by an increase in current consumption at constant rotational speed.

14. A method for grinding coffee in a coffee grinder, comprising the steps of a) providing a coffee grinder according to any one of claims 1 to 11 or a coffee machine according to any one of claims 12 or 13; b) filling the housing upper part (1) of the coffee grinder with coffee beans or coarsely ground coffee; and c) grinding the coffee beans or the coarsely ground coffee.

15. The method according to claim 14, characterised in that the DC motor (7) has a rotation angle sensor, preferably a rotation angle sensor selected from the group consisting of an optical rotation angle sensor, a magnetic rotation angle sensor and combinations thereof, the rotation angle sensor particularly preferably comprising or consisting of a Hall sensor or a GMR sensor, and, based on at least one signal from the rotation angle sensor, i) a rotational speed of the DC motor (7) is regulated; and / or ii) a rotational direction of the rotor (9) of the DC motor (7) is regulated; and / or iii) a blockage of the DC motor (7) is detected and, in the event a blockage is detected, the rotational direction of the DC motor (7) is reversed for a specific period of time, particularly 1 to 5 seconds, and / or for a specific number of revolutions, in particular 0.25 to 10 revolutions; and / or iv) a grinding point of the first grinding disc (5) on the second grinding disc (6) is detected, and, in the event a grinding point is detected, this is set as the setting for the finest grind of the coffee grinder, the current consumption of the DC motor (7), in addition to the at least one signal from the rotation angle sensor, is also optionally taken into account in detecting the grinding point, a grinding point is optionally detected either by a drop in rotational speed at constant current consumption or by an increase in current consumption at constant rotational speed; the aforementioned method steps are optionally performed by a controller of the DC motor (7), by a controller of the coffee grinder, or by a controller of the coffee machine.