Grinding machine for grinding legume products, in particular for beverage vending machines

Abstract

A grinding device (1) for grinding a legume product, in particular for a beverage vending machine (A), has a grinder (2) driven by an electric motor (7) for moving the ground product through an outlet (4A); and a measuring device (10) for measuring the amount of ground product flowing through the outlet (4A); the measuring device (10) has: a guide channel (12) communicating with the outlet (4A) and configured to form and move a uniform flow (16) of abrasive product in a supply direction (13); and a measuring wheel (18) partially housed in the channel (12) to cooperate, in use, with the flow (16) of abrasive product; the wheel (18) is free to rotate inside the channel about an articulation axis (21) orthogonal to the supply direction (13), and an electronic sensing system (36) detects the angular position of the wheel (18) about the axis (21) and outputs an electrical signal which allows the electronic control unit (8) to calculate the angular movement of the wheel (18) about the axis (21), and calculating the amount of abrasive product flowing along the channel (12) towards the outlet (4A) based on the angular movement.

Description

[0001] Citations of Related Applications

[0002] This application claims the priority of Italian Patent Application No. 102022000016245 filed on July 29, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a grinder for grinding bean products, in particular for beverage vending machines. Background Art

[0004] In the field of machines for preparing beverages in general, and in particular in the field of machines for preparing coffee, to which the following description will refer without loss of generality, it is known to use a grinding and dosing device comprising a grinder which receives a flow of coffee beans and dispenses a flow of ground coffee having a predetermined particle size that can be chosen according to the type of beverage to be prepared.

[0005] In some applications, in particular in the field of vending, the grinding and dosing device also includes a volumetric doser, which receives the ground coffee flow from the grinder and doses the ground coffee flow before sending it to a beverage preparation unit (such as, for example, a brewing assembly).

[0006] Typically, a dosing device comprises a dosing chamber which has a constant and predetermined volume depending on the amount of ground coffee required for preparing the beverage and which is gradually filled until completely full and is thereafter emptied by opening a discharge opening through which the ground coffee is discharged into the beverage preparation unit.

[0007] Despite their widespread use, known volumetric dosing machines of the above-mentioned type are not entirely satisfactory, since they do not ensure precise dosing and, above all, consistent dosing over time. This inaccuracy stems from the failure to take into account, when dosing, the variations in the coarseness of the ground coffee caused by the inevitable wear of the grinder, and therefore requires regular calibration by a specialized technician in order to limit variations in the dosed amount of ground coffee dispensed by the dosing machine.

[0008] Another cause of inaccuracy arises from the fact that part of the ground coffee inevitably accumulates gradually near or around the inlet and discharge openings of the dosing chamber, thereby obstructing the normal flow and the intended movement of the movable wall for opening / closing the inlet and discharge openings. The presence of agglomerates of ground coffee inside the chamber (the finer the ground coffee and the more sensitive it is to humidity, the greater the agglomerates) can lead to the risk of deviations in the amount of ground coffee dispensed by the dosing chamber: if part of the ground coffee fails to leave the dosing chamber, the amount of ground coffee is less than expected; conversely, if, in addition to the amount of ground coffee in the dosing chamber, an amount of ground coffee not dispensed in a previous dosing is dispensed (which accumulates around the chamber opening), the amount of ground coffee is greater than expected.

[0009] Besides this, volumetric dosing devices are usually not very flexible, ie they are not suitable for rapid adjustment to dispense partial dosing amounts, or in any case to dispense a multiple of an amount which differs from what the dosing chamber can accommodate.

[0010] In other applications, typically in the domestic coffee machine industry or in the hotel industry, no volumetric dosing device is used, but the ground product is dosed based on the operating time of the grinder or on the number of revolutions of the grinder rotor. In these cases, the amount of ground coffee to be dispensed for preparing a beverage is therefore determined indirectly, i.e. estimated based on the operating time of the grinder or the expected number of revolutions of the grinder rotor.

[0011] While this approach enables simple, continuous and virtually instantaneous variation of the amount of ground coffee required for a beverage (even a different beverage), it still presents problems in some situations (and these situations are not uncommon, including an irregular flow of coffee beans delivered to the grinder, or even a complete lack of coffee beans in the grinder's supply hopper).

[0012] In these cases, the expected amount of ground coffee is theoretically dispensed, while in practice only a portion is dispensed, or even none is dispensed.

[0013] In order to avoid this problem, the counting of the number of revolutions of the grinder drive motor is combined with checking the current consumed by the grinder drive motor. Although, on the one hand, this association makes it possible to detect a discontinuity or absence of coffee beans supplied to the grinder, which is signaled by an oscillation or a rapid reduction in the current consumed by the grinder motor; on the other hand, the dosing accuracy of the ground coffee cannot be improved, since the change in the current consumed by the grinder motor is in any case detected later than when the discontinuity actually occurs, so that at least part of the dosed amount is done with less ground coffee.

[0014] The linking of two measuring devices for measuring the current consumption and the number of revolutions of the grinder motor also has the following disadvantages: on the one hand, it increases the production costs of the grinding and dosing device; on the other hand, it requires frequent and regular maintenance and control operations in order to ensure the expected efficiency of the two measuring devices and the synergy between them.

[0015] US2017 / 231419 A1 discloses a grinder for preparing powdered brewing materials, which includes a main housing, a grinding assembly, and an unloading assembly for measuring the amount of brewing powder to be unloaded. The unloading assembly has an unloading motor and a measuring cylinder. When the user puts the brewing material into the main housing, the grinding assembly grinds the brewing material into brewing powder. The brewing powder falls into the unloading assembly. When the unloading motor actuates the measuring cylinder to rotate, the brewing powder is deposited in the filter. Therefore, the user can grind tea leaves, Chinese herbs, petals, etc. to obtain fresh brewing powder. Using fresh brewing powder to brew liquid retains nutrients and flavor. In addition, there is no need to use bags for packaging brewing powder, thereby reducing environmental pollution and packaging costs.

[0016] US2013 / 091802 A1 discloses a coffee filter bag making machine comprising a bean hopper which feeds an electric bean grinder by gravity, which ejects the grounds into the hopper. A precise manual dispenser feeds a predetermined amount of grounds into a filter bag by gravity. The filter bag is disposed on a roll of perforated filter bags. The filter bag is sealable. A roll of impermeable bag sections is provided to accommodate one or more prepared filter bags. The impermeable bag is evacuated and sealed using an integrated vacuum / seal assembly. Summary of the invention

[0017] The object of the present invention is to provide a grinder for grinding pulse products which makes it possible to overcome the above-mentioned drawbacks.

[0018] According to the present invention, as claimed in the accompanying claims, there is provided a grinder for grinding bean products, in particular for use in beverage vending machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention will now be described with reference to the accompanying drawings, which show non-limiting embodiments of the invention, in which:

[0020] Figure 1 A grinder according to the invention in a coffee beverage preparation machine, which is schematically and partially shown, is schematically shown in perspective and side view;

[0021] Figure 2 yes Figure 1 a cross section of a grinding machine shown in ; and

[0022] Figure 3 Shown in perspective and greatly enlarged scale Figure 1 Details in. DETAILED DESCRIPTION

[0023] The present invention will now be described in detail with reference to the accompanying drawings to enable those skilled in the art to produce the invention and use it. Various modifications to the described embodiments will be apparent to those skilled in the art without departing from the scope of protection of the invention as defined in the appended claims, and the general principles described may be applied to other embodiments and applications. Therefore, the present invention should not be considered to be limited to the embodiments described and illustrated herein, but should be allowed to have the broadest scope of protection consistent with the features described and claimed herein.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. In the event of a conflict, the present specification (including definitions) shall prevail. In addition, these examples are provided for illustrative purposes only and should not be considered restrictive.

[0025] To facilitate understanding of the embodiments described herein, reference will be made to some specific embodiments and specific language will be used to describe these embodiments. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0026] exist Figure 1 and Figure 2 In the figure, reference numeral 1 as a whole refers to a grinding machine for grinding bean products P( Figure 2 , for example coffee), which can preferably but not exclusively be used in a coffee beverage preparation machine A (known per se and partially shown).

[0027] The grinding device 1 comprises a grinder 2 known per se, comprising an attachment frame 3 , an inlet 4 for the product P to be ground, an outlet 4A for the ground product P and a movable grinding member 5 for grinding the bean product P.

[0028] The movable grinding member 5 is mounted to rotate about a fixed axis 6 under the thrust of an electric motor 7 controlled by an electronic control unit 8 of the coffee beverage preparation machine A.

[0029] The grinding device 1 also comprises measuring means 10 for measuring the amount of ground product flowing through the outlet 4A and making it possible to dose the ground product in predetermined portions in order to obtain a corresponding coffee beverage.

[0030] refer to Figure 2The measuring device 10 comprises a frame 11 coupled and permanently connected to the frame 3 at the outlet 4A and defining a channel 12 extending in a direction 13 orthogonal to the fixed axis 6 .

[0031] Channel 12 has a rectangular section and comprises a bottom wall 14, transverse to axis 6, and two side walls 15, facing each other and projecting upwards from bottom wall 14. Bottom wall 14 may be perpendicular to axis 6 or inclined to facilitate the discharge of the ground product.

[0032] The channel 12 has an inlet connected to the outlet 4A to receive the ground product from the grinder 2, and the channel is configured to form a continuous flow 16 of the ground product in a supply direction or an emptying direction, and to move the flow in a supply direction or an emptying direction, which coincides with the direction 13 and is directly towards a known beverage production unit (not shown in the figure).

[0033] refer to Figure 2 The measuring device 10 also comprises a measuring wheel 18 arranged inside the channel 12 so as to cooperate with the flow 16 of the ground product.

[0034] refer to Figure 2 , and specifically refer to Figure 3 , the wheel 18 is keyed to a middle portion 19 of an articulated shaft 20 having an axis 21 orthogonal to the direction 13 and the axis 6 and parallel to the bottom wall 14, and two opposite end portions 22. The wheel 18 is externally delimited by a circular peripheral surface 29 and is mounted with respect to the channel 12 such that said peripheral surface 29 is arranged at a minimum distance D from the bottom wall 14.

[0035] exist Figure 1 In the example shown in FIG. 1 , each portion 22 extends through a respective wall 15 and is rotatably and slidably engaged with an associated shaped guide slot 24 formed through the respective side wall 15 .

[0036] In the described example, each slit 24 has an opening 25 open upwards for entry and insertion of the corresponding part 22, and starting from the corresponding opening 25, the slit has: a section 26, which is essentially vertical and orthogonal to the bottom wall 14; and a section 27, which is inclined relative to the supply direction 13 and preferably curved, which has an upwardly tilted concave shape and ends at the bottom with a stop surface or end-of-travel surface, on which the corresponding part 22 rests and abuts.

[0037] The configuration of the slots 24 is selected to enable the shaft 20 to move freely and continuously along a predetermined spaced path that allows the wheel 18 to move away from the bottom wall 14 so that the wheel 18 can be arranged in a plurality of operating positions solely under the thrust of the grinding product.

[0038] In a different embodiment, the portion 22 of the wheel 18 is assembled on the corresponding side wall 15 in an axially fixed position, so that the distance of the peripheral surface 29 from the bottom wall 14 always remains constant.

[0039] With reference to the figures, the wheel 18 is delimited by two opposite front faces 30 orthogonal to the axis 21 ; each front face 30 carries a set of radial ribs (indicated by 31 ) which project cantilevered from the corresponding front face 30 parallel to the axis 21 .

[0040] In the example shown, the ribs 31 are of equal size and configuration, and the size of each rib measured parallel to the axis 21 increases from the periphery towards the axis 21. Each rib 31 preferably terminates towards the peripheral surface 29 with an end section which is radially withdrawn from the peripheral surface 29, so that the outer annular portion 35 of the corresponding front surface 30 is free of ribs, as in Figure 2 and Figure 3 Visible in.

[0041] In different embodiments, the ribs 31 may have different sizes and configurations.

[0042] refer to Figure 3 , the measuring device 10 finally comprises an electronic sensing system 36 designed to sense the angular position of the wheel 18 about the axis 21 and to output an electrical signal enabling the electronic control unit 8 to calculate the angular movement of the wheel 18 about the axis 21 and, based on the calculated angular movement, the amount of ground product flowing along the channel 12 towards the outlet 4A. The electronic control unit 8 is preferably programmed to control the operation of the electric motor 7 of the grinder 2 based on the calculated amount of product.

[0043] Conveniently, the electronic sensing system 36 comprises a phonic wheel 37 keyed to one end portion 22 of the shaft 20 , and a sensor 38 associated with the phonic wheel 37 and connected to the electronic control unit 8 of the coffee beverage preparation machine A.

[0044] The tone wheel 37 may be of any known type suitable for the purpose, for example, it may be of magnetic induction type, or it may be of optical (encoder) type, or it may be of capacitive type. A sensor 38 (which may be of electromagnetic or Hall effect type, or may be a reflective optical sensor, depending on the type of tone wheel used) is arranged facing the toothed edge of the wheel 18 to detect the passage of the teeth of the wheel 18, and outputs a pulsed electrical signal having a frequency representative of the rotational speed of the tone wheel 37.

[0045] In use, the ground product exiting the grinder 2 through the outlet 4A enters the channel 12 and moves forward in the channel, thereby forming a stream 16 of ground product having an almost constant cross-section and a thickness that is always greater than the minimum distance D, whatever the beverage to be prepared and therefore whatever the amount of ground product required. In this way, as in Figure 2 It can be seen in FIG. 2 that the peripheral portion 18A of the wheel 18 is always inserted in the flow 16 of abrasive product, which therefore causes the wheel 18 to rotate about the axis 21 .

[0046] The traction of the wheel 18 is ensured by the ribs 31, the peripheral end sections of which penetrate into the same flow 16 and are intercepted by the exiting flow 16 of ground product. Furthermore, the impact between the flow 16 of ground product and the ribs 31 advantageously breaks up or breaks up any agglomerates or lumps of ground product present around the wheel 18.

[0047] The rotation speed of wheel 18 is measured by an electronic sensing system 36 and a corresponding signal is transmitted to the electronic unit 8 which (knowing the amount of ground product required to produce the requested beverage and the ratio between the amount of ground product supplied to the outlet of channel 12 and the pulses of the signal output by sensor 38) stops the electric motor 7 as soon as the amount of ground product required to produce the requested beverage has passed through the outlet of channel 12.

[0048] On the contrary, it seems clear that no signal is emitted when the flow of ground product is below a minimum threshold or is absent. In this case, the wheel 18 is arranged in its lower end of travel position while no longer in contact with the ground product, and the unit 8 therefore senses that the wheel 18 has stopped rotating, thereby immediately generating a beverage dispensing stop signal.

[0049] On the contrary, when the thickness of the flow 16 of abrasive product changes, the presence and shape of the slots 24 enable the wheel 18 to rise freely from the bottom wall 14, so as to avoid forming an obstacle blocking the supply of abrasive product, but without changing the conditions for engaging the wheel 18 with the abrasive product. In any case, the shape of the slots 24 must be such that the movement of the wheel 18 relative to the bottom wall 14 remains within a range that allows the precise control of the amount of abrasive product flowing in the channel 12 to be maintained and, moreover, that ensures the continuity of the connection between the sensor 38 and the sound wheel 37.

[0050] It is clear from the above that, on the one hand, the device 10 allows extremely accurate measurement of the amount of ground product conveyed in the channel 12 and therefore allows accurate dosing of the ground product so that the beverages produced have exactly the same properties.

[0051] On the other hand, the device 10 enables the quantity of ground product intended for producing different beverages to be varied arbitrarily in a very short time, without requiring any changes in configuration or structure.

[0052] It then also appears clear from the above that the specific production features of the channel 16, the wheel 18 and the connection of this wheel 18 avoid any blockage of the ground product moving forward and avoid the formation of agglomerates (the main cause of errors, dosing problems and subsequent changes in the quality of the dispensed beverage).

[0053] The inclusion of the upwardly opening slot 24 simplifies and minimizes the time required for routine cleaning and control operations.

[0054] It also appears clear from the above that the assembly 1 described may be modified, or variants of this assembly produced, without departing from the scope of protection defined by the claims.

[0055] In particular, the wheel 18 may be made differently than the one described by way of example, or coupled to a channel different from that shown, but always with the goal of ensuring maximum fluidity and maximum uniformity of the forward movement of the ground product. For example, instead of a single wheel, two wheels arranged in parallel may be used.

[0056] Furthermore, the wheel 18 may be coupled to the wall 30 in a manner different from that shown so as to still be able to move from and toward the bottom wall 14 in a continuous or discrete manner between the aforementioned end of downstroke position or position of minimum distance from the bottom wall 14 and at least one raised position where the wheel is at a distance from the bottom wall 14 greater than the aforementioned minimum distance.

[0057] Furthermore, the described grinding device 1 has the advantage of being easily applicable to grinding devices already provided with a general dosing system (in particular, those based on digital control of the rotation of the grinder motor) in order to obtain better dosing accuracy.

[0058] Additional advantages are: simple structure and therefore reduced production costs; easy cleaning due to less powder clogging in the components; and easy automatic adjustment of the dosing by calculating data of the pump, the volumetric doser and the mechanical forces of the brewing assembly based on previously dispensed coffee. For example, if coffee is dispensed with a time of 10 seconds and a flow rate of 4 grams per second, the software can be adjusted by calibrating the next cup of coffee (by increasing or decreasing the amount of ground product to be dispensed to change the previously obtained parameters).

Claims

1. A grinding device (1) for grinding bean products, in particular for use in a beverage vending machine (A); The grinding device (1) comprises: A grinder (2) having an attachment frame (3), an inlet (4) for a bean product to be ground, a movable grinding member (5) for grinding said bean product; an electric drive motor (7) for driving said movable grinding member (5); an outlet (4A) for a ground product; and a metering device for metering a certain amount of ground product supplied by the grinding device (1); Characterized in that the dosing device comprises a measuring device (10), which comprises: a guide channel (11) connected to the outlet (4A) and configured to form a uniform flow (16) of ground product in a supply direction (13) and to advance the uniform flow in the supply direction; and at least one wheel (18), partly housed in said guide channel (11) and coupled to said attachment frame (3), to freely rotate under the thrust of said flow (16) of ground product about an articulation axis (21) transverse to said supply direction (13); The measuring device (10) also includes an electronic sensing system (36) for sensing the angular position of the wheel (18) about the articulation axis (21) during the flow of the stream (16) of ground product and outputting an output signal indicative of the angular position of the wheel about the articulation axis to allow the electronic control unit (8) to calculate the amount of ground product flowing through the outlet (4A) based on the output signal.

2. The grinding device (1) according to claim 1, wherein: The electronic control unit (8) controls the electric drive motor (7) for driving the movable grinding member (5) based on the output signal output by the electronic sensing system (36).

3. The grinding device (1) according to claim 1 or 2, wherein: The electronic sensing system (36) comprises a tone wheel (37) keyed to the shaft (20) of the wheel (18) and a sensor (38) associated with the tone wheel (37) and connected to the electronic control unit (8).

4. The grinding device (1) according to any one of the preceding claims, wherein: The guide channel (11) has a bottom wall (14), and wherein the exterior of the wheel (18) is delimited by a peripheral surface (29) coaxial with the articulation axis (21) and spaced apart from the bottom wall (14).

5. The grinding device (1) according to claim 4, wherein: The wheel (18) carries a plurality of radial ribs (31) extending radially from the articulation axis (21).

6. The grinding device (1) according to claim 5, wherein: The wheel (18) has two opposite front surfaces (30) orthogonal to the articulation axis (21); each of the front surfaces (30) carries a set of associated radial ribs (31) axially cantilevered from the respective front surface (30).

7. The grinding device (1) according to claim 5 or 6, wherein: Each radial rib (31) has a dimension measured parallel to the articulation axis (21), said dimension increasing towards the articulation axis (21).

8. The grinding device (1) according to any one of claims 4 to 7, wherein: The articulation axis (21) is movable relative to the bottom wall (14) between a lower end position in which the wheel (18) is arranged at a minimum distance (D) from the bottom wall (14) and at least one raised position in which the wheel (18) is arranged at a distance from the bottom wall (14) greater than the minimum distance (D).

9. Grinding device (1) according to claim 8, further comprising guiding means (26) to guide the articulation axis (21) continuously along spaced paths allowing the wheel (18) to move away from the bottom wall (14).

10. The grinding device (1) according to claim 9, wherein: The spacing path comprises at least one section (27) which is inclined relative to the supply direction (13).

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