coffee grinding machine

Abstract

A coffee grinding machine is described, comprising a machine body, a grinding chamber, first and second bars movable relative to each other to grind coffee beans, and a discharge duct for receiving ground coffee discharged from the grinding chamber and conveying the ground coffee toward a container, the discharge duct being connected to the machine body by magnetic attraction, the total magnetic attraction being greater than the weight of the discharge duct, for example, the total magnetic attraction being equal to the weight of the discharge duct plus at least 50 grams, for example 50-150 grams.

Description

[Technical Field]

[0001] The present invention relates to a machine for grinding coffee beans, which can be a stand-alone machine or can be incorporated into an at least partially automatic machine for the production of coffee-based beverages, such machines also known simply as "coffee grinding machines", "coffee grinders" or "mills". [Background technology]

[0002] Two categories of coffee grinding machines are known, one category uses volumetric dosing means and has a storage container, the other category is of the "on-demand" type, i.e., immediate dosing and does not store ground coffee. The present invention relates to both categories of machines, but preferably to on-demand type coffee grinding machines, i.e., immediate dosing and does not store ground coffee.

[0003] Coffee grinding machines are known which comprise a body housing two superimposed grinding burrs, one of which is rotated by an electric motor and the other of which is axially movable relative to the first burr upon actuation of a threaded ring which engages inside the body housing the burrs.

[0004] Once ground, the coffee is conveyed from the grinding chamber, typically through a tunnel to an exhaust duct.

[0005] Typically, the discharge duct has a converging shape to properly direct the ground coffee into a container, which is generally a filter inserted into a filter holder. As is known, the filter holder with the filter filled with ground coffee reversibly engages with a dispensing group of an espresso coffee machine for preparing espresso coffee.

[0006] US Pat. Nos. 5,699,298, 5,799,302 and 5,899,313 describe coffee grinding machines. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 9066629(B1) [Patent Document 2] US Patent Application Publication No. 2018 / 199750(A1) [Patent Document 3] US Patent Application Publication No. 2021 / 113020(A1) Summary of the Invention [Problem to be solved by the invention]

[0008] The Applicant has noticed that coffee powder tends to accumulate on the inner walls of the discharge duct (as well as in other areas) of coffee grinding machines. Obviously, coffee powder that accumulates on the walls of the discharge duct needs to be removed for various reasons. The first reason is that the coffee deposited on the walls can deteriorate and lead to the development of mold and bacteria, which can be transferred to the coffee powder used to prepare espresso coffee. These molds and bacteria significantly reduce the quality of the prepared beverage, both from an organoleptic and hygienic point of view.

[0009] To avoid the aforementioned drawbacks, manufacturers of coffee grinding machines recommend that the discharge duct be periodically removed and thoroughly cleaned. Unfortunately, however, some users of coffee grinding machines neglect to maintain and clean the discharge duct, and only take measures when the situation significantly worsens. For example, some users may only remove the discharge duct when there is a problem with the discharge of ground coffee powder or when the amount of ground coffee powder discharged is significantly less than desired. Alternatively, users may notice an unpleasant odor coming from the coffee grinding machine and ground coffee.

[0010] A further problem can be a clogged discharge duct. In fact, if the discharge duct is blocked in any way, the coffee cannot be discharged and may return upwards towards the bar, blocking it. This compressed coffee is very difficult to remove and may require some disassembly of the machine to clean it.

[0011] The applicant aimed to provide a solution to the aforementioned problems and to provide an engagement system for an exhaust duct which obliges, or at least encourages, the user to frequently remove the exhaust duct in order to prevent it from becoming even partially blocked. Advantageously, the engagement system according to the invention also achieves the aim of allowing maintenance and cleaning.

[0012] The Applicant has observed that the accumulation of coffee powder on the inner walls of the exhaust duct results in a not inconsiderable increase in the weight of the exhaust duct.

[0013] According to the invention, a coffee grinding machine is provided which comprises a system configured to disengage the exhaust duct and prevent operation of the machine if a preset weight of the exhaust duct is exceeded.

[0014] In particular, a magnetic system is provided that connects the discharge duct to the coffee grinding machine body, and the magnetic attraction force is set to keep the discharge duct connected to the machine body up to a certain weight, taking into account the dry weight of the discharge duct and the weight of the discharge duct with a predetermined amount of coffee powder on its inner walls (an amount that is considered to be acceptable and not excessive). When an excessive amount of coffee powder accumulates on the inner surface of the discharge duct, the magnetic attraction force is not sufficient to keep the discharge duct firmly engaged in place. Separation of the discharge duct will interrupt the electrical circuit or in any other way cut off the power supply to the machine, and the user will have to disassemble the discharge duct to remove the powder that has accumulated on the inner walls or other parts of the discharge duct.

[0015] A safety device is preferably provided to prevent the exhaust duct from falling and becoming completely separated from the rest of the machine. [Means for solving the problem]

[0016] According to a first aspect, the present invention provides a coffee grinding machine comprising a machine body, a grinding chamber, first and second bars movable relative to each other to grind coffee beans, and a discharge duct for receiving the ground coffee discharged from the grinding chamber and conveying the ground coffee towards a container, wherein the discharge duct is connected to the machine body by a total magnetic attraction force which is greater than the mass (weight) of the discharge duct.

[0017] According to an embodiment, the total magnetic attraction force is greater than the mass (weight) of the exhaust duct by a predetermined amount corresponding to the amount of coffee powder deposited in that section of the exhaust duct after a predetermined number of coffee bean grinding cycles.

[0018] According to an embodiment, the total magnetic attraction force is substantially equal to the mass (weight) of the exhaust duct after a predetermined number of operating hours or days.

[0019] According to an embodiment, the exhaust duct comprises an engaging ring.

[0020] According to an embodiment, the engagement ring comprises two radially protruding lugs, the radially protruding lugs each include a magnet, and the machine body includes a ferromagnetic material or plate fixed to the machine body; or Each of the radially projecting lugs includes a ferromagnetic material, and the machine body includes at least one magnet on each lug.

[0021] According to an embodiment, the claimed coffee grinding machine also comprises a mechanical safety device to prevent the discharge duct from falling due to excessive accumulation of coffee powder or due to accidental causes.

[0022] According to an embodiment, each of the protruding lugs has a through hole, the machine body has a threaded hole in each of the two lugs, and the mechanical safety device has a screw that is screwed into each screw hole, so that a portion of the shank of the screw protrudes relative to the lug, and the shank forms a fall path for the exhaust duct when the exhaust duct is disengaged from the machine body.

[0023] According to an embodiment, the coffee grinding machine also comprises a microswitch for cutting off the power supply to the coffee grinding machine when the exhaust duct is not engaged.

[0024] According to an embodiment, the exhaust duct comprises a chute, the chute comprises a tongue, the tongue configured to depress a microswitch to maintain the exhaust duct in a configuration engaged with the machine body by magnetic force.

[0025] According to an embodiment, the total magnetic attraction force is equal to the weight of the exhaust duct plus at least 50 grams, in other words, the total magnetic attraction force is at least 50 grams greater than the weight of the cleaned exhaust duct (without coffee deposits).

[0026] According to an embodiment, the total magnetic attraction force is greater than the weight of the cleaned exhaust duct (without coffee deposits) in the range of 50 grams to 200 grams, for example 50 grams to 100 grams, or 50 grams to 150 grams.

[0027] According to an embodiment, the total magnetic attraction force is equal to the weight of the exhaust duct plus at least 100 grams, in other words, the total magnetic attraction force is at least 100 grams greater than the weight of the cleaned exhaust duct (without coffee deposits).

[0028] According to an embodiment, the total magnetic attraction force is in the range of 100 grams to 200 grams, for example 100 to 180 grams or 120 to 160 grams, greater than the weight of the cleaned exhaust duct (without coffee deposits).

[0029] The invention will become more apparent from the following description, given by way of non-limiting example, read with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0030] [Figure 1.1] 1 shows an example of a coffee grinding machine according to the present invention; [Figure 1.2] Fig. 1.1 shows a longitudinal section of the machine. [Figure 2.1] FIG. 1 is a view of a coffee grinding machine showing the exhaust or output duct in exploded form. [Figure 2.2] FIG. 1 is a view of a coffee grinding machine showing the exhaust or output duct in exploded form. [Figure 3.1] 2 shows the coffee grinding machine according to FIG. 1, with the discharge duct engaged in the grinding configuration; FIG. [Figure 3.2] 2 shows the coffee grinding machine according to FIG. 1, with the discharge duct engaged in the grinding configuration; FIG. [Figure 3.3] 2 shows the coffee grinding machine according to FIG. 1, with the discharge duct engaged in the grinding configuration; FIG. [Figure 3.4] 2 shows the coffee grinding machine according to FIG. 1, with the discharge duct engaged in the grinding configuration; FIG. [Figure 3.5] 2 shows the coffee grinding machine according to FIG. 1, with the discharge duct engaged in the grinding configuration; FIG. [Figure 4.1] 2 shows the coffee grinding machine according to FIG. 1, with the exhaust duct disengaged in a configuration in which grinding cannot occur. [Figure 4.2] 2 shows the coffee grinding machine according to FIG. 1, with the exhaust duct disengaged in a configuration in which grinding cannot occur. [Figure 4.3] 2 shows the coffee grinding machine according to FIG. 1, with the exhaust duct disengaged in a configuration in which grinding cannot occur. [Figure 4.4] 2 shows the coffee grinding machine according to FIG. 1, with the exhaust duct disengaged in a configuration in which grinding cannot occur. DETAILED DESCRIPTION OF THE INVENTION

[0031] Figure 1.1 shows, purely by way of example, a coffee grinding machine 1 according to the invention. Figure 1.2 shows a longitudinal section of the machine shown in Figure 1.1, illustrating some of its main components. It will be apparent that the machine according to the invention may take any form quite different from that shown in Figures 1.1 and 1.2. As the invention relates only to some of the components of the machine, other components that are not essential for the understanding of the invention will not be described and / or illustrated.

[0032] The machine 1 according to the invention comprises a hopper 2 for receiving the coffee beans to be ground, a grinding chamber 3 with grinding bars 4, 5 for grinding the coffee beans received from the grinding chamber, and a discharge duct 20 for conveying the ground coffee powder towards a collection container. Figure 1.2 also shows a motor 6 with a transmission belt for rotating one of the two bars 4, 5 relative to the other.

[0033] Typically, the collection container is a filter 30 of a filter holder 32 for an espresso coffee machine. The coffee grinding machine 1 may also comprise a device 9 for varying the mutual distance between the bars 4 and 5 and thereby adjusting the particle size of the coffee powder discharged from the grinding chamber.

[0034] Advantageously, the coffee grinding machine 1 may comprise a machine body 8 housing the various components. The machine body 8 may be at least partly made of metal.

[0035] The coffee grinding machine 1 may comprise a support 10 for supporting the filter holder 32 in the correct position so that the ground coffee is directed towards the filter 30 supported by the filter holder 32 .

[0036] The discharge duct 20 preferably has a converging shape to convey the ground coffee from a larger cross section substantially corresponding to the cross section of the grinding chamber to a smaller cross section that matches the diameter of the filter 30 .

[0037] As shown in Figures 2.1 and 2.2, the discharge duct 20 according to the present invention comprises an inner cone 22 for properly conveying ground coffee powder discharged from the grinding chamber, a chute 23 and an engagement ring 24 for removably fixing the chute 23 to the main body 8.

[0038] The inner cone 22 is substantially funnel-shaped. According to an embodiment, the inner cone 22 has a protruding lip 221 at the large diameter opening.

[0039] The inner cone 22 may be made of metal, but is preferably made of a thermoplastic material.

[0040] The chute 123 has the function of receiving the ground coffee from the inner cone 22 and directing it into the receiving vessel 30. Advantageously, it has a part of its surface that is open, in other words it is not a closed tube (or cone). The chute can be made of metal or any thermoplastic material.

[0041] The chute 23 is integrally or detachably connected to an engagement ring 24. The engagement ring 24 is internally shaped to substantially match the edge 221 of the internal cone 22. In other words, when the engagement ring 24 is connected to the machine body 8, the engagement ring 24 supports the internal cone 22 and the chute 23.

[0042] The engagement ring 24 is removably connected to the machine body 8. According to the invention, the engagement ring 24 is connected by magnetic forces. For example, the engagement ring 24 comprises at least one magnet 28 and the body 8 of the coffee grinding machine 1 to which the engagement ring 24 is connected comprises at least one ferromagnetic material 82, e.g. a ferromagnetic plate 82, as shown in Figure 3.4. In another embodiment, the engagement ring 24 comprises (or is substantially made of) at least one ferromagnetic material and the body 8 of the coffee grinding machine 1 to which the engagement ring 24 is connected comprises one or more magnets, e.g. a magnetic plate.

[0043] It is clear that alternatives to the above-mentioned solution are also possible: for example, the engagement system, which is currently magnetic, could also be realized by mechanical fixing elements, i.e. transverse springs or snap-fit ​​pushers.

[0044] The magnet 28 may be a single magnet or multiple magnets 28.

[0045] According to an embodiment, the magnets 28 are small cylindrical in shape and are preferably equally angularly spaced.

[0046] In one embodiment, the engagement ring 24 includes one or more radially outwardly projecting lugs 25. For example, two radially projecting lugs 25 may be provided. Each projecting lug 25 includes a magnet 28 configured to generate a magnetic attraction with a ferromagnetic plate 82 or any corresponding ferromagnetic portion of the body 8 of the machine 1.

[0047] According to the present invention, the total magnetic attraction force between the engagement ring 24 and the machine body 8 is the sum of the magnetic forces of the individual magnets.

[0048] Typically, during use of the coffee grinding machine, coffee powder accumulates inside the discharge duct 20, for example on the walls of the inner cone 22 and / or on the surface of the chute 23. If the discharge duct 20 is not cleaned regularly, the coffee powder forms a layer and the weight of coffee powder accumulated in the discharge duct can reach 100-120 grams or more. Obviously, the amount of coffee powder that can accumulate in the discharge duct varies greatly and depends, for example, on the degree of compression and type of particle size of the coffee, as well as on the ambient conditions (especially humidity).

[0049] According to the invention, the total magnetic attraction force is calculated to be greater than the weight of the discharge duct alone, in particular the total magnetic attraction force is substantially equal to the sum of the weight of the discharge duct and the weight of the allowable amount of ground coffee to be deposited, i.e. TMF=MDC+MWP+THR, where: TMF is the total magnetic force defined by the sum of the magnetic forces of the individual magnets, MDC is the weight of the cleaned discharge duct without any coffee grounds deposited on it, The MWP is the allowable weight of coffee powder that can be lost by depositing on the walls (and / or other parts) of the exhaust duct 20. The allowable weight of coffee powder corresponds to the maximum amount of coffee powder that must be removed by cleaning the exhaust duct 20.

[0050] THR is a term that takes into account the thrust force exerted by the coffee powder being discharged from the grinding chamber. Indeed, as the coffee powder accumulates, it will at some point come into contact with moving parts and be pushed out by them. Furthermore, if a blockage occurs, the particles being discharged will collide with stationary particles, stop, and begin to increase in density, being pushed out in various directions. This force cannot be quantified exactly, but it accounts for a significant part of the force required to disengage the discharge duct. This component increases as the amount of accumulated coffee increases. If the amount of accumulated coffee is small, this component is irrelevant.

[0051] The allowable weight of coffee grounds can be determined by the manufacturer based on experience and the specific shape of the exhaust duct, which in turn influences the amount of coffee grounds that do not reach the filter and remain on the walls of the exhaust duct or in any corners thereof.

[0052] For example, a manufacturer of coffee grinding machines may find that in normal daily use (taking into account the number of doses ground at atmospheric pressure and at a reference ambient temperature, given air humidity conditions) the amount of coffee powder that tends to accumulate in the discharge duct ranges between x grams and y grams. Under the same ambient and operating conditions, the amount of coffee powder that accumulates in the discharge duct over two days may be estimated to be twice the amount per day. As the number of days increases, the thrust force component becomes more pronounced.

[0053] If a manufacturer wants to encourage baristas to remove accumulated coffee to prevent clogging and keep the exhaust duct clean every day, the total magnetic force TMF is determined to be equal to the exhaust duct MDC plus weight x, or more conservatively, weight y (multiplied by a safety factor if necessary). In this way, the barista can more easily get through a typical working day.

[0054] Similarly, if a manufacturer wants to encourage baristas to clean the exhaust duct every week, the total magnetic force TMF is determined to be equal to the exhaust duct MDC plus weight x, or more conservatively, weight y (multiplied by the number of working days, e.g., 5, 6, or 7 days). It is advantageous to assume a safety factor. In this way, baristas can more easily complete a typical working week. The safety factor can be, for example, 10% more than the allowable weight MWP.

[0055] Alternatively, the manufacturer may aim to prevent clogging and therefore calibrate the total magnetic force using an exhaust duct with an accumulated amount of coffee powder in the range of about 50g to 200g, or about 100g to 160g, or about 110g to about 150g, or about 120g to 140g, or any other subrange.

[0056] By setting the total magnetic force in this way, if the barista does not clean the exhaust duct after a certain period of time, the total magnetic force will no longer be able to hold the exhaust duct 20 to the machine body 8. In other words, if the weight of ground coffee accumulated in the exhaust duct exceeds the allowable weight, the dirty exhaust duct will be too heavy for the magnets to perform their function of stably fixing the duct to the machine body 8.

[0057] For example, if the total magnetic force TMF is equal to MDC+y grams because the manufacturer recommends daily cleaning, further use of the machine without cleaning the exhaust duct at the end of the day will result in the exhaust duct 20 being disengaged (possibly in a short period of time), making it impossible to use the machine with a dirty exhaust duct.

[0058] For example, x can be about 2 g, 3 g, or 4 g. For example, y can be about 4 g, 5 g, or 6 g.

[0059] Typically, blockages can occur suddenly due to poor machine operation or incorrect use by the user, for example if the user improperly hits the outlet of the discharge cone with the filter holder. Alternatively, they can occur during normal use, after grinding several hundred kilograms of coffee, e.g., 300-500 kg, depending on the amount of coffee deposited on the surface. This corresponds to at least one to two months' work in a very busy bar.

[0060] According to an embodiment, the total magnetic force is about 5% greater than the weight of the exhaust duct.

[0061] According to an embodiment, the total magnetic force is about 10% greater than the weight of the exhaust duct.

[0062] According to an embodiment, the total magnetic force is about 15% greater than the weight of the exhaust duct.

[0063] According to an embodiment, the total magnetic force is between about 10% and 30% of the weight of the exhaust duct.

[0064] According to one embodiment of the present invention, a first safety device is provided to prevent the exhaust duct 20 from falling as a result of an accident or when the weight of the dirty exhaust duct is greater than the total magnetic force. The first safety device is mechanical and defines a landing position for the disengaged exhaust duct. The landing position may be a small distance away from the position where the exhaust duct is engaged.

[0065] According to one embodiment, each lug 25 projecting radially from the engagement ring 24 is provided with a through hole 26 for a screw 27. The machine body 8 to which the engagement ring 24 is connected is provided with a threaded hole 81 for the screw 27 (for each through hole 26 in the lug). The length of the shank of each screw 27 is longer than the sum of the thickness of the lug 25 and the depth of the screw hole. In this way, the head 271 of the screw 27 remains spaced apart from the lug 25 even when the screw 27 is fully screwed into the hole. If the exhaust duct 20 becomes detached, it can drop a distance 272 corresponding to the part of the shank of the screw 27 that projects downward relative to the lug 25 when the exhaust duct 20 is connected to the machine body 8.

[0066] Figures 3.1, 3.2, 3.3 and 3.4 show the safety screw 27 and the part of the shank 272 that corresponds to the maximum fall distance when the exhaust duct 20 is disengaged. Figures 4.1, 4.2 and 4.3 show the exhaust duct 20 in the disengaged state. It is clear how the exhaust duct 20 has "landed" on the head 271 of the screw 27 and is resting on it. The exhaust duct 20 has fallen over a distance (also indicated by 272) that is limited by the cross section of the screw visible in Figures 3.1, 3.2, 3.3 and 3.4. The fall path can be one millimeter or in any case several millimeters, but is advantageously less than 10 millimeters, for example about 5 millimeters.

[0067] According to an embodiment of the present invention, the coffee grinding machine also comprises a microswitch 40 for cutting off the power supply to the motor that rotates (at least) one of the bars when the discharge duct is in a disengaged configuration. Figure 3.5 shows the microswitch 40 in a closed circuit configuration in which the motor 6 is powered and able to rotate at least one of the bars 3 and 4, while Figure 4.4 shows the microswitch 40 in an open circuit configuration corresponding to a configuration in which the discharge duct 20 is no longer supported by magnetic forces.

[0068] According to one embodiment, a conductive tongue 41 connected to the chute 23 of the exhaust duct 20 may be provided to close the microswitch 40. Alternatively, a reed sensor type metal contact switch may be used.

Claims

1. A coffee grinding machine (1) comprising a machine body (8), a grinding chamber (3), a first bar (4) and a second bar (5) movable relative to each other to grind coffee beans, and a discharge duct (20) for receiving ground coffee discharged from the grinding chamber (3) and conveying the ground coffee towards a container (30), wherein the discharge duct (20) is connected to the machine body (8) by a total magnetic attraction force which is greater than the weight of the discharge duct (20).

2. Coffee grinding machine (1) according to claim 1, wherein the total magnetic attraction force is greater than the weight of the discharge duct (20) by a predetermined amount corresponding to the amount of coffee powder accumulated in that portion of the discharge duct (20) after a predetermined number of coffee bean grinding cycles.

3. Coffee grinding machine (1) according to claim 1, wherein the total magnetic attraction force is substantially equal to the weight of the exhaust duct (20) after a predetermined number of operating hours or days.

4. Coffee grinding machine (1) according to any one of claims 1 to 3, wherein the discharge duct (20) is provided with an engagement ring (24).

5. The engagement ring (24) comprises two radially projecting lugs (25), each of said radially projecting lugs (25) comprises a magnet (28), and said machine body (8) comprises a ferromagnetic material or ferromagnetic plate (82) fixed to said machine body (8); or Coffee grinding machine (1) according to claim 4, wherein each of said radially projecting lugs (25) comprises a ferromagnetic material, and said machine body (8) comprises at least one magnet in each ear (25).

6. Coffee grinding machine (1) according to claim 4 or 5, further comprising a mechanical safety device (27, 28, 29, 81) for preventing the discharge duct (24) from falling due to excessive accumulation of coffee powder or due to accidental causes.

7. 7. A coffee grinding machine (1) according to claim 6, wherein the protruding ears (25) each have a through hole (26), the machine body (8) has a threaded hole (81) in each of the two lugs (25), and the mechanical safety device comprises a screw (27) that is screwed into each screw hole (81), such that a portion (272) of the shank of the screw (27) protrudes relative to the lug (25), and the portion (272) of the shank forms a falling path for the discharge duct (20) when the discharge duct is disengaged from the machine body (8).

8. Coffee grinding machine (1) according to any one of claims 1 to 7, further comprising a microswitch (40) for cutting off the power supply to the coffee grinding machine (1) when the exhaust duct (20) is not engaged.

9. Coffee grinding machine (1) according to claim 8, wherein the discharge duct (20) comprises a chute (23), the chute (23) comprising a tongue (41), the tongue (41) being configured to depress the microswitch (40) to maintain the discharge duct (20) in a configuration engaged with the machine body (8) by the total magnetic force.

10. Coffee grinding machine (1) according to any one of the preceding claims, wherein the total magnetic attraction force is equal to the weight of the discharge duct (20) plus at least 50 grams.

11. Coffee grinding machine (1) according to any one of the preceding claims, wherein the total magnetic attraction force is at least equal to the weight of the discharge duct (20) plus 50 to 200 grams or 50 to 150 grams.

12. Coffee grinding machine according to claim 10 or 11, wherein the total magnetic attraction force is equal to the weight of the discharge duct (20) plus at least 100 grams.

13. Coffee grinding machine (1) according to any one of the preceding claims, wherein the total magnetic attraction force is equal to the weight of the discharge duct (20) plus 100 to 200 grams, for example 100 to 180 grams or 120 to 160 grams.

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