Coffee grinder

Abstract

A coffee grinder (1) for grinding coffee beans into ground coffee, comprising at least one container (2) or supply element for coffee beans and at least one grinding device (4, 9, 41, 42) for grinding the coffee beans. The grinding device comprises at least one first grinding element and at least one second grinding element (41, 42), the coffee beans being ground between the two grinding elements (41, 42) by relative rotation of the two grinding elements (41, 42), the distance (40) between the two grinding elements during grinding determining the grind of the ground coffee, and at least one grinding element (42) being driven by a motor (4). According to the invention, there is provided an adjustment element (19), wherein the distance (40) between the two grinding elements (41, 42) can be adjusted by rotating the adjustment element (19), and a magnetic rotary position sensor (30) which clearly and directly or indirectly determines the absolute rotary position of the adjustment element (19) as a measurement of the distance (40) and provides this measurement for further control of the coffee grinder (1).

Description

Technical Field

[0001] This invention relates to a coffee grinder, a method for operating the coffee grinder, and the uses of such a coffee grinder. Background Technology

[0002] A coffee grinder is a device that processes roasted coffee beans into ground coffee. In the past, a large portion of coffee was ground by distributors and then consumed by end customers in crushed form, both in the private and commercial sectors. However, customer needs have now shifted further, as only freshly ground coffee can produce truly good brews. Therefore, end customers are increasingly using coffee grinders, not only in coffee bars but also in restaurants and similar establishments, some of which are even private.

[0003] Today, the quality of brewed coffee largely depends on the quality of the grind, as only coffee with the appropriate grind size is truly suitable for a particular brewing process or machine type. Therefore, grind setting is crucial for coffee grinders. Until now, grind settings have typically been manually adjusted using an external handwheel or adjustment ring. The problem is that this setting is too imprecise, especially due to the mechanical implementation, becoming unreliable over time and, in some cases, even gradually developing into a systematic bias.

[0004] This is where the invention comes into play. Summary of the Invention

[0005] Therefore, one of the objectives of this invention is to provide a coffee grinder that allows for more reliable adjustment of the grind size and is simple and robust in design.

[0006] The present invention aims to provide a coffee grinder for grinding coffee beans, comprising at least one container or feeding element for the coffee beans and at least one grinding device for grinding the coffee beans. The grinding device includes at least a first grinding element and a second grinding element, wherein the coffee beans are ground between the first and second grinding elements by the relative rotation of the two grinding elements, and the distance between the two grinding elements during the grinding process determines the degree of grind. At least one grinding element is typically driven by a motor.

[0007] The coffee grinder according to the present invention is characterized by having an adjustment element that allows the distance between two grinding elements to be adjusted by rotating the adjustment element, and a magnetic rotation position sensor that directly or indirectly determines the absolute rotation position of the adjustment element as a distance measurement result, and enables the measurement result to be used for further control of the coffee grinder.

[0008] Absolute rotational position is a precisely defined rotational position. This means that with the magnetic rotational position sensor stationary, a component containing an embedded bipolar magnet rotating in front of the sensor will rotate less than 360° within the machine, within the maximum distance adjustment range.

[0009] It has been demonstrated that this magnetic rotary position sensor offers the possibility of unexpectedly simple and, in relation to this coffee grinder, unexpectedly stable measurement of the distance between the grinding elements. In this coffee grinder, conditions are challenging because the motor generates a strong stray field, and the intense vibrations of the grinder and motor make it practically impossible to use many other common sensors. Surprisingly, the magnetic rotary position sensor performs this task with remarkable reliability.

[0010] According to a first preferred embodiment, this coffee grinder is characterized by: a first grinding element, preferably in the form of a grinding ring, grinding cone, or grinding disc, and disposed in a fixed position; a second grinding element, preferably in the form of a grinding ring, grinding cone, or grinding disc, and rotatably mounted, rotating relative to the first grinding element during grinding; and the second grinding element being connected to a shaft and driven by a motor via the shaft. The axial position of either the first or second grinding element can now be adjusted in this device by means of an adjusting element.

[0011] More preferably, the grinding element driven by the motor is adjusted by an adjusting element. Accordingly, according to another preferred design, the coffee grinder is designed such that the shaft is supported in at least one bearing element, preferably in at least one bearing ring, and at least one bearing of these bearing elements is mounted in a displaceable manner, and the shaft is axially connected to the bearing element such that axial displacement of the bearing element causes a corresponding displacement of the shaft in the same axial direction. Now, the adjusting element is preferably designed in the form of an adjusting pin and connected to the bearing element in such a way as to the axial axis position, the adjusting pin being installed such that rotation of the adjusting pin causes simultaneous axial displacement of the bearing element.

[0012] The bearing element is preferably a bearing bushing that guides the motor shaft and does not rotate itself. The bearing bushing preferably also has a tapered bore, which is preferably perpendicular to the axis of the shaft, into which the tapered part of the adjusting pin engages. The motor shaft is preferably preloaded by a spring in a direction away from the grinding housing at its lower end, i.e., at the end opposite to the end of the grinding housing that has the grinding element, typically on the side of the motor away from the grinding housing. The bearing bushing preferably contains a bearing whose outer bearing ring accommodates the motor shaft (e.g., at a step of the motor shaft that tapers in the direction of the grinding housing), thereby preventing axial displacement of the motor shaft through the running disc flange (which holds the rotating grinding element) via an inner bearing ring with a fastening device (e.g., with axial threads).

[0013] The adjusting pin can preferably be threaded (e.g., the adjusting pin can have external threads and travel in a bearing housing with internal threads), and the adjusting pin can engage with its tip in a bushing within or on the bearing element. In this case, axial displacement of the adjusting pin causes axial displacement of the bearing element. In this design, the tip of the adjusting pin is preferably tapered, and the slotted guide portion is in the form of at least one corresponding inclined side, which is preferably in a recess of the bearing element.

[0014] Furthermore, the actuating element, preferably in the form of an adjusting pin, can be mechanically coupled to an adjusting element, preferably in the form of an adjusting ring, which is manually operated by the user. The magnetic rotary position sensor can measure the rotational position of the actuating element directly on the actuating element or on another component firmly connected to it. Alternatively, the measurement can be performed indirectly on a rotating element mechanically coupled to the actuator, which is different from the user's adjusting element, and whose rotation is coupled to the actuator's rotation, and which itself rotates a maximum of less than 360° within the adjustment range.

[0015] In any case, the element that measures the rotational position by the magnetic sensor is preferably different from the user's adjustment element.

[0016] According to another preferred embodiment, an actuating element in the form of an adjusting pin is mechanically coupled to an adjusting element, for example, in the form of an adjusting ring, which is manually operated by the user. A magnetic rotary position sensor measures the rotational position of the actuating element directly on the adjusting pin or on another component firmly connected to the adjusting pin. A bipolar magnet is arranged on the axis of the adjusting pin, with the magnetic poles radially (preferably arranged on the side of the head end opposite to the bearing element), and the rotary position sensor is axially arranged above the bipolar magnet. It can be seen that the distance difference between the fixed magnetic rotary position sensor and the magnet arranged on the rotating part caused by this configuration is so small that they do not affect the measurement accuracy of the sensor.

[0017] An adjusting element in the form of an adjusting pin can preferably be mechanically coupled to an adjusting element in the form of an adjusting ring, which is manually operated by the user. A magnetic rotary position sensor can indirectly measure the rotational position on a rotating element mechanically coupled to the adjusting element and distinct from the user-operated adjusting element. The rotation of this rotating element is coupled to the rotation of the adjusting element and, within the adjustment range, allows for a maximum rotation of less than 360°. The ratio of the rotation of the rotating element to the rotation of the adjusting pin is in the range of 1.5:1 to 1:1.5, preferably in the range of 1.1:1 to 1:1.1, and particularly in the range of 1:1. Preferably, no more than two transmission stages are provided between the adjusting pin and the rotating element.

[0018] Another preferred embodiment of the coffee grinder presented herein is characterized by a gear arranged on an adjusting pin, which is externally coupled to a drive gear having external teeth (preferably, the gear and the drive gear have substantially the same diameter), and a bipolar magnet is arranged on or embedded in the drive gear along its axis, or the drive gear is coupled to another rotating element via another transmission stage constructed for another gear or belt, the other rotating element being thus coupled to the rotation of the actuating element and performing a maximum rotation of less than 360° within the adjustment range, and a bipolar magnet is arranged on or embedded in the other rotating element along its axis.

[0019] The coffee grinder may also have a weighing sensor for measuring the weight of the ground coffee effectively inserted into the filter container. The weighing sensor is preferably located in the foot of the coffee grinder outside the housing.

[0020] The coffee grinder preferably also has an additional display, and the absolute rotational position from the magnetic rotational position sensor is further preferably transmitted to a central control system, which correlates the absolute rotational position with the distance of the gap width between the grinding elements and processes the information for output to the display or for further control or adjustment.

[0021] For example, the display shows the actual value of the rotation position or gap width and the target value required for the desired abrasion, and / or instructions for manually changing a setting element operated by the user in a certain direction until the target value is reached. Preferably, additional optical and / or acoustic and / or mechanical feedback elements are provided to indicate to the user whether the target value has been reached.

[0022] However, a drive (e.g., a small electric motor) may also be provided to automatically and in a controlled manner move the adjustment element to a rotational position corresponding to a grind selected by the user and / or automatically determined, based on a measurement of the absolute rotational position of the adjustment element and a measurement from an additionally provided measuring unit, i.e., a measurement of the weight of the coffee powder.

[0023] Furthermore, the present invention relates to a method for operating a coffee grinder as described above. The proposed method is characterized in particular by the coffee grinder including at least one display showing an actual value of the rotational position or gap width, or a target value required for a desired grind size, and / or at least one instruction for manually changing a setting element operated by the user in a certain direction until the target value is reached. When the user manipulates the adjustment element, the indication on the display preferably changes dynamically until the desired target value is reached; more preferably, additional optical and / or acoustic and / or mechanical feedback elements may be provided to indicate to the user whether the target value has been reached.

[0024] Other embodiments of the invention are set forth in the dependent claims. Attached Figure Description

[0025] Preferred embodiments of the present invention are described below with reference to the accompanying drawings, which are intended to illustrate the present preferred embodiments of the invention and not to limit the invention. In the drawings,

[0026] Figures 1a-1c A coffee grinder according to a first embodiment is illustrated in a schematic diagram, wherein, in Figure 1a A schematic side view is shown in the diagram. Figure 1b A view of the sensor arrangement is shown in the diagram, and... Figure 1c A side view of the sensor arrangement is shown in the figure;

[0027] Figure 2 A coffee grinder according to a second embodiment is shown in a schematic side view. Detailed Implementation

[0028] Figure 1aA schematic diagram of a coffee grinder 1 with a built-in sensor is shown.

[0029] It is a basically standard coffee machine with the following components: In the housing 3, two grinding rings 41 and 42 with vertical axes of rotation are arranged at the top. Typically, the upper grinding ring 41 is fixed and beans are loaded from above through a hopper 2, which is located above the housing and filled with beans. Here, very schematically, a grinding gap 40 exists between the two grinding rings 41 and 42, in which the beans are ground to the desired size between the contours of the two rings. The desired grind size depends on the desired coffee type, etc., and is set by the width of the grinding gap 40. This will be discussed again later.

[0030] The ground coffee is then delivered radially or even axially from the grinding gap 40 via the supply line 12, which is schematically shown, and directed to the outlet 10. Through the outlet 10, the coffee typically falls by gravity into the filter container 6, which typically has a handle 6a and is designed to engage with a bayonet lock on the bottom side of a coffee or espresso machine for the actual brewing process.

[0031] In the design example shown here, the filter container 6 stands upright on the filter holder 7, which rests on the foot 5 of the coffee grinder. Alternatively, such a filter holder can protrude horizontally from the housing 3 and hold the filter container for approximate fork-shaped filling.

[0032] In the example shown here, the foot 5 contains a weighing sensor 8 for measuring the weight of the coffee being placed in the filter container 6. This weight measurement is known in itself and can be used to ensure better and more consistent quality of brewed coffee. The desired weight can be set individually according to the desired settings or the type of coffee being brewed.

[0033] In the example shown here, both grinding rings 41 and 42 are arranged vertically with their axes aligned. The upper grinding ring 41 is fixed, while the lower grinding ring 42 is rotatably mounted. The lower grinding ring 42 is driven by a motor 4, located in the lower part of the housing and shown schematically here. This motor drives a shaft 9, which is securely connected to the lower grinding ring 42 and is mounted in at least one bearing ring 15. The axial position of the shaft 9, and therefore the lower grinding ring 42, is determined by the axial position of the bearing ring 15. If the bearing ring 15 is pushed upward accordingly, the width of the grinding gap 40 decreases. In this case, the motor 4 itself can move axially, or the shaft 9 can be mounted in the motor, allowing it to move slightly axially within the desired range.

[0034] As mentioned above, grind size is crucial for the desired coffee consistency. Therefore, a mechanism is provided that allows for individual adjustment of the grind size for each grinding cycle as needed.

[0035] Therefore, in the example shown here, the bearing ring 15 has a tapered recess 18 with an inclined side 43 facing the grinding ring, as shown. Figure 1c As shown. An adjusting pin 19, horizontally mounted in the bearing 20, engages in the tapered recess 18. The adjusting pin 19 has an external thread 22 that extends into a corresponding internal thread in the bearing 20. Furthermore, the adjusting pin 19 has a tapered, tapered tip 21 corresponding to the inclined side 43. On the side opposite to the tip 21, the adjusting pin 19 in the design example shown here has a square section 24 that axially engages in the gear 25. A corresponding square recess exists in the injection-molded component 25, and the gear 25 has teeth on its circumference.

[0036] Now, as schematically shown in the figure, the grinding gap 40 is adjusted mechanically such that the gear 25 is connected to an adjusting ring 13 in the cover region of the housing 3 via a mechanical coupling 26 having multiple gear ratios. There, grinding scales are typically present on the housing and, for example, on the blade 14 used for actuation. If the blade 14 is brought to a certain scale position on the adjusting ring 13 or the adjusting cover by rotating the ring, both the cover and the gear 25 rotate via the mechanical coupling 26. By rotating the gear 25, the adjusting pin 19 is axially pushed deeper to the left into the tapered recess 18 via the thread 22 in the bearing 20, so that... Figure 1a In the replica shown, the grinding gap 40 is narrowed. The tapered tip 21 slides on the inclined side 43 and moves the bearing ring 15 upward in a controlled manner. This closes the grinding gap 40.

[0037] To reopen the grinding gap, the adjusting ring 13 is rotated in the opposite direction, and the grinding gap reopens due to gravity or the return spring on the motor shaft. The return spring is not strictly necessary, as the weight of the motor 4, shaft 9, and bearing ring 15 is typically so great that a separate return force is not required to open the grinding gap 40; however, a return spring can be provided for safety reasons.

[0038] The main problem with this design is that the mechanical connection from gear 25 and mechanical link chain 26 to adjusting ring 13 naturally has a large clearance, and this clearance becomes increasingly prone to occur, especially during extended use. This reduces the grinding precision required for reliable coffee to an unacceptable level.

[0039] According to the invention, a magnetic sensor is now directly mounted on the actual axial adjustment mechanism, which determines the gap width 40. A magnet 27 is axially inserted or placed on the side of the gear 25 opposite to the adjusting pin 19. The north and south poles are arranged on different radial sides, and a magnetic sensor 30 is disposed in a fixed position similarly above the magnet 27. The magnetic sensor 30 is a programmable magnetic 360° angle sensor for non-contact, high-resolution angular position measurement, and is typically based on magnetic ring vertical Hall (CVH) technology. It is an IC, preferably with a high angular refresh rate in the range of 25 microseconds to 3200, and its zero position can be calibrated.

[0040] Preferably, a disc-shaped magnet magnetized along the diameter is used as magnet 27.

[0041] Such a sensor is essentially unaffected by the gap width 37 between the measuring surface of the magnetic sensor 30 facing the magnet 27 and the actual magnet 27. That is, the gap 37 has no significant effect over the entire adjustment range of the grinding gap within the relevant dimension of the maximum axial displacement of the gear 25 of 1.5 mm.

[0042] For example, the sensor is of the type available from Allegro Microsystems, denoted A1330.

[0043] The error tolerance of this sensor is typically within a maximum range of 1.5°, and usually within the range of + / -0.4° to + / -1.1°. This results in very high accuracy in degree-of-freedom measurement because rotations less than 360° are converted by thread 22 into translations typically 1 mm to 2 mm in the axial direction along the bearing ring 15. Therefore, thread 22 is a fine thread with a pitch of 2 mm.

[0044] From the basis Figure 1b As can be seen in the top view, the sensor 30 (shown schematically in dashed lines here) is arranged as symmetrically as possible on the magnet 27 in the axial direction, and these two elements are arranged coaxially with the circumference of the adjusting pin 19 and the gear 25, as schematically shown here. If the gear 25 is rotated by manipulating the adjusting ring 13, as... Figure 1c As indicated by arrows 35 and 36, the adjusting pin 19 is further pushed into the tapered recess 18, and the bearing ring 15 moves upward in the direction indicated by arrow 35, thereby reducing the grinding gap 40 by causing the side 21 to slide on the side 43.

[0045] The signal from the magnetic sensor 30 is transmitted to the central control unit 16 via data line 32. If the material to be ground is also weighed, the central control unit 16 can also receive data from the weighing sensor 8 via a corresponding additional data line 34. The central control unit 16 is powered by a corresponding main power line, which also powers the motor and is not shown here, and then controls the display 17.

[0046] Among other things, the display 17 also shows the user his current absolute split position. For example, the user can set the desired abrasion level on the display and then receive an indication of which direction to rotate the adjustment pin to set the abrasion level to the desired value. This can be done, for example, by displaying the set value and the actual value measured by the sensor 30 next to each other on the display, and by giving the user auditory and / or visual feedback if the two values ​​are the same after adjusting the paddle 14.

[0047] Automatic calibration can be achieved by automatically setting the value to zero when the stop point is reached, or by prompting the user to start a calibration routine when the stop point is reached.

[0048] exist Figure 2 The example illustrates another construction method when space is limited. Here, it is not possible to position the magnetic sensor 30 directly on the side of gear 25 facing away from the adjusting pin 19. In this case, for example due to the narrowness of the housing, another gear 38 can be placed on the side of gear 25 facing the adjusting pin, and gear 38 can be connected to drive gear 39. This gear 39 now has an axial recess in which the magnet 27 described above is inserted, and the magnetic sensor is now assigned to one side of the bearing ring 15. A drive belt can also be used instead of gears. Furthermore, in addition to the two gears 38 and 39 shown here, another belt drive can be provided until the actual rotating element serves as the carrier of the magnet 27. However, no more than two such drives should exist.

[0049] Alternatively, the additional transmission gear 39 and the attached gear 38 can be omitted, and another gear can be directly connected to gear 25. However, care must be taken to keep the rotational state under control. For the sensor, there should be no rotation exceeding 360°, otherwise the magnetic sensor 30 will no longer be in the defined state after one rotation cycle. For this purpose, the preferred solution is to connect as directly as possible to the adjusting pin or the like via a 1:1 transmission ratio of the two gears 38 or 39 shown here, or, if directly connected to the teeth of gear 25, to another method. It must be accepted that the other gear of the direct meshing gear 25 of the type of gear 39 must have a large radius within the radius region of gear 25.

[0050] List of reference numerals

[0051]

Claims

1. A coffee grinder (1) for grinding coffee beans into ground coffee, comprising at least one container (2) or supply element for coffee beans and at least one grinding device (4, 9, 41, 42) for grinding said coffee beans. in, The grinding device includes at least a first grinding element (41) and a second grinding element (42). The coffee beans are ground between the first grinding element (41) and the second grinding element (42) by the relative rotation of the two grinding elements (41, 42). The distance (40) between the two grinding elements during the grinding process determines the degree of grind of the coffee. At least one grinding element (42) is driven by a motor (4). in, An adjustment element (19) is provided, wherein the distance (40) between the two grinding elements (41, 42) can be adjusted by rotating the adjustment element (19), and The device includes a magnetic rotational position sensor (30), which directly or indirectly determines the absolute rotational position of the adjustment element (19) as the measurement result of the distance (40), and enables the measurement result to be used for further control of the coffee grinder (1). The first grinding element (41) is fixedly mounted, and the second grinding element (42) is rotatably mounted. The second grinding element (42) rotates relative to the first grinding element (41) during the grinding process. The second grinding element (42) is connected to a shaft (9) and driven by a motor (4) via the shaft (9). The shaft (9) is supported in at least one bearing element, and at least one of these bearing elements (15) is supported in a displaceable manner, and the shaft (9) is supported in the bearing element (15) in an axially connected manner, such that displacement of the bearing element (15) in the axial direction causes a corresponding displacement of the shaft in the same axial direction. Its features are, The adjusting element (19) is designed in the form of an adjusting pin (19) and connected to the bearing element (15). The adjusting pin (19) is installed such that rotation of the adjusting pin (19) causes axial displacement of the bearing element (15) simultaneously. Furthermore, the adjusting pin (19) is installed by a thread (23), and the tip (21) of the adjusting pin (19) engages in the bearing element (15) or in the guide (18, 43) on the bearing element (15), and the axial displacement of the adjusting pin (19) causes the axial displacement of the bearing element (15).

2. The coffee grinder (1) according to claim 1, characterized in that, The first grinding element (41) is in the form of a grinding ring or a grinding cone.

3. The coffee grinder (1) according to claim 1 or 2, characterized in that, The second grinding element (42) is in the form of a grinding ring, a grinding disc, or a grinding cone.

4. The coffee grinder (1) according to claim 1 or 2, characterized in that, The at least one bearing element is a bearing ring (15).

5. The coffee grinder (1) according to claim 1 or 2, characterized in that, The tip (21) of the adjusting pin (19) is tapered, and the guide (18) is formed in the form of at least one inclined side (43) in the recess of the bearing element (15).

6. The coffee grinder (1) according to claim 1 or 2, characterized in that, The adjusting element (19), in the form of an adjusting pin, is mechanically connected to a first adjusting element (13, 14) operated manually by the user, and the magnetic rotary position sensor (30) is directly connected to the adjusting element (19), or The rotational position of the adjusting element (19) is measured directly on another component (25), which is securely connected to the adjusting element (19). Alternatively, the rotational position of the adjusting element (19) can be indirectly measured on a rotating element (39) that is mechanically connected to the adjusting element (19) and is different from the first adjusting element (13, 14) for the user. The rotation of the rotating element (39) is coupled to the rotation of the adjusting element (19) and thus allows for a maximum rotation of less than 360° within the adjustment range.

7. The coffee grinder (1) according to claim 1 or 2, characterized in that, The adjusting element (19), in the form of an adjusting pin, is mechanically connected to a first adjusting element (13, 14), in the form of an adjusting ring (13), which is manually operated by the user, and the magnetic rotary position sensor (30) is directly connected to the adjusting element (19), or The rotational position of the adjusting element (19) is measured directly on another component (25), which is securely connected to the adjusting element (19). Alternatively, the rotational position of the adjusting element (19) can be indirectly measured on a rotating element (39) that is mechanically connected to the adjusting element (19) and is different from the first adjusting element (13, 14) for the user. The rotation of the rotating element (39) is coupled to the rotation of the adjusting element (19) and thus allows for a maximum rotation of less than 360° within the adjustment range.

8. The coffee grinder (1) according to claim 1 or 2, characterized in that, The first grinding element (41) is fixedly disposed, and the second grinding element (42) is rotatably mounted and rotates relative to the first grinding element (41) during the grinding process. The second grinding element (42) is connected to the shaft (9) and driven by the motor (4) through the shaft (9). The shaft is preloaded in a direction away from the second grinding element (42).

9. The coffee grinder (1) according to claim 1, characterized in that, A first grinding element (41) in the form of a grinding ring, grinding disc, or grinding cone is fixedly disposed on a fixed disc flange, and a second grinding element (42) in the form of a grinding ring, grinding disc, or grinding cone is rotatably mounted on a running disc flange and rotates relative to the first grinding element (41) during the grinding process. The second grinding element (42) is connected to a shaft (9) and driven by the motor (4) through the shaft (9), and the shaft is preloaded in a direction away from the second grinding element (42).

10. The coffee grinder (1) according to claim 1 or 2, characterized in that, The first grinding element (41) is fixedly disposed, and the second grinding element (42) is rotatably mounted and rotates relative to the first grinding element (41) during the grinding process. The second grinding element (42) is connected to a shaft (9) and driven by the motor (4) through the shaft (9). The shaft is preloaded in a direction away from the second grinding element (42) by a helical spring arranged on the side of the motor (4) away from the second grinding element (42).

11. The coffee grinder (1) according to claim 1 or 2, characterized in that, The adjusting element (19) in the form of an adjusting pin is mechanically connected to a first adjusting element (13, 14) in the form of an adjusting ring (13) operated manually by the user. The magnetic rotational position sensor (30) measures the rotational position of the adjusting element (19) directly on the adjusting pin (19) or on another component (25) that is firmly connected to the adjusting pin (19). A bipolar magnet (27) is arranged on the axis of the adjusting pin (19), wherein the magnetic poles are in the radial direction. The bipolar magnet (27) is arranged on the side away from the bearing element (15), and the rotational position sensor (30) is arranged axially above the bipolar magnet (27).

12. The coffee grinder (1) according to claim 11, characterized in that, The adjusting element (19) is mechanically coupled to the first adjusting element (13, 14), and the magnetic rotational position sensor (30) is mechanically coupled to a rotating element (39) different from the first adjusting element (13, 14) for the user, wherein the rotation of the rotating element (39) is coupled to the rotation of the adjusting element (19), and a maximum rotation of less than 360° is performed within the adjustment range, and the magnetic rotational position sensor (30) measures the rotational position. The ratio of the rotation of the rotating element (39) to the rotation of the adjusting pin (19) is in the range of 1.5:1 to 1:1.

5.

13. The coffee grinder (1) according to claim 12, characterized in that, The ratio of the rotation of the rotating element (39) to the rotation of the adjusting pin (19) is in the range of 1.1:1 to 1:1.1, and wherein no more than two transmission stages are provided between the adjusting pin (19) and the rotating element (39).

14. The coffee grinder (1) according to claim 12, characterized in that, A gear (38) is arranged on the adjusting pin (19), the gear (38) being connected to a transmission gear (39) having external teeth via external teeth, wherein the gear (38) and the transmission gear (39) have substantially the same diameter, and the bipolar magnet (27) is disposed on or embedded in the transmission gear (39) on the axis of the transmission gear (39), or the transmission gear (39) is disposed via another transmission stage constructed for another gear or another belt, the transmission gear (39) being connected to another rotating element, the rotation of which is thus coupled with the rotation of the adjusting element (19) and performs a maximum rotation of less than 360° within the adjustment range, the bipolar magnet (27) being disposed on or embedded in the other rotating element on the axis of the other rotating element.

15. The coffee grinder (1) according to claim 1 or 2, characterized in that, The coffee grinder also includes a weighing sensor (8) for measuring the weight of the ground coffee effectively inserted into the filter container (6), the weighing sensor (8) being arranged in the foot (5) of the coffee grinder located outside the housing (3).

16. The coffee grinder (1) according to claim 1 or 2, characterized in that, The coffee grinder also includes a display (17), and the absolute rotational position is transmitted from the magnetic rotational position sensor (30) to a central control unit (16), and the control unit (16) associates the absolute rotational position with a distance (40) representing the gap width between the grinding elements (41, 42), and prepares the association result to be output to the display (17).

17. The coffee grinder (1) according to claim 16, characterized in that, The display (17) shows the actual value of the absolute rotational position or the distance (40) and the target value required for the desired abrasion, and / or instructions for manually changing the first adjustment element (13, 14) operated by the user in a certain direction until the target value is reached. Therefore, optical and / or acoustic and / or mechanical feedback elements are additionally provided to indicate to the user whether the set point value has been reached.

18. The coffee grinder (1) according to claim 1 or 2, characterized in that, A driver is provided that automatically and in a controlled manner causes the adjustment element (19) to rotate to a position corresponding to an abrasive degree selected by the user and / or automatically determined, based on a measurement of the absolute rotational position of the adjustment element (19).

19. The coffee grinder (1) according to claim 12, characterized in that, The ratio of the rotation of the rotating element (39) to the rotation of the adjusting pin (19) is in the range of 1.1:1 to 1:1.

1.

20. The coffee grinder (1) according to claim 12, characterized in that, The ratio of the rotation of the rotating element (39) to the rotation of the adjusting pin (19) is 1:

1.

21. The coffee grinder (1) according to claim 1 or 2, characterized in that, A driver is provided that, based on a combination of a measurement of the absolute rotational position of the adjustment element (19) and a measurement from an additionally provided weighing sensor (8), i.e., a measurement of the weight of the ground coffee, automatically and in a controlled manner causes the adjustment element (19) to rotate to a position corresponding to a grind value selected by the user and / or automatically determined.

22. A method of operating the coffee grinder (1) according to any one of claims 1-21, Its features are, The coffee grinder (1) has at least one display (17) on which the actual value of the absolute rotational position or the distance (40) and the desired value required for the desired grind are displayed, and / or an instruction for manually changing a first adjustment element (13, 14) operated by the user in a certain direction until the target value is reached, and wherein the instruction changes dynamically as the user manipulates the first adjustment element (13, 14) until the desired target value is reached, and wherein, additionally, optical and / or acoustic and / or mechanical feedback elements are provided to indicate to the user whether the target value has been reached.

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