Low acoustic impact coffee machine

Abstract

A coffee machine (10) comprises a grinding device (11), a hopper (12) able to contain coffee beans and provided at the lower part with an outlet aperture (13) for the beans which is disposed above the grinding device (11), a containing body (14) comprising a compartment (15) provided with a housing zone for said grinding device (11) and a housing zone for said hopper (12), and a decoupling gasket (16) disposed between the outlet aperture (13) of the hopper (12) and a loading aperture (17) of the grinding device (11).

Description

[0001] “LOW ACOUSTIC IMPACT COFFEE MACHINE”

[0002] FIELD OF THE INVENTION

[0003] The present invention concerns a “quiet” coffee machine, that is, having lower noise emission, in particular an automatic coffee machine comprising an integrated grinding device.

[0004] BACKGROUND OF THE INVENTION

[0005] Automatic machines comprising a brewing unit and a grinding device, integrated in the machine body and able to grind coffee beans into powder when the preparation of a beverage is required, are known.

[0006] Due to the vibrations generated by the grinding device, however, these machines are very noisy when preparing and dispensing a beverage.

[0007] Although there are several sources of noise in the machine, including water pump activation, bean grinding, and movement of the brewing unit, the most significant is the grinding of the beans.

[0008] The grinding device is generally disposed in an upper position of the machine body, interposed between a hopper containing the beans and a feed duct through which the ground coffee powder is fed to the brewing unit.

[0009] During the grinding of the beans, the grinding device generates vibrations that are transmitted to the other machine components in contact with it, such as the hopper, the feed duct and also the machine’s frame that supports the grinding device.

[0010] Generally, in known machines there are usually only damping elements positioned at the points in which the mill rests on the frame, whose anti-vibration effect is however limited. The remaining components are rigid and in connection with each other, and therefore the vibrations emitted by the grinding device are transmitted to the components, generating noise.

[0011] To overcome the high noise level, in recent years some rigid components have been replaced with others made of rubber material, such as for example the duct for delivering the ground coffee powder from the grinding device to the brewing unit, and furthermore anti-vibration packings, springs, or suchlike have been introduced between the fixed parts and the moving parts to prevent the transmission of motion between them, and thus the generation of noise. Other known solutions provide to reduce the speed of the motor, since the human ear’s response is not linear and some tones with high peaks in the acoustic spectrum can be very annoying. In rotating mechanisms, these frequencies are proportional to the rotational speed and therefore reducing this speed brings benefits in terms of noise emission reduction. In these known solutions, however, to avoid compromising the time required to prepare a beverage, larger grinding areas have to be provided in order to maintain a suitable grinding flow rate, resulting in increased costs and footprints within the machine body.

[0012] Further known solutions to reduce the noise of the grinding device provide to install the same inside a fully sealed box made of damping polymer material. Such a box is normally closed at the upper part by the hopper and its lid.

[0013] From document US2022 / 225818AI, an automatic type coffee machine is also known, comprising an elastomeric acoustic insulation membrane shaped so as to follow the external shape of the hopper, positioned in the machine body’s compartment, which extends below the hopper and is provided with a through aperture connecting the hopper and the mouth of the grinding device.

[0014] A disadvantage of this known solution is that the membrane is at least partly pre-compressed between the hopper and the grinding device, and therefore does not allow for an effective decoupling between the machine’s components, whereby the damping of the acoustic waves and noise is limited.

[0015] This disadvantage is more pronounced when light hoppers are used, which cannot counteract the forces generated by the grinding device.

[0016] Document US2022061583A1 concerns a coffee machine grinder unit comprising an upper grinder and a lower grinder, and a device for adjusting the coffee bean grinding level, which is provided with a rotary adjustment element to which a vertically movable support is attached, which carries the upper grinder, and with a guide that transforms the rotation of the adjustment element into a vertical displacement of the support, thus modifying the distance between the two grinders and the grinding level. A gasket is positioned between the adjustment element and the movable support, the purpose of which is to close a gap between the two elements.

[0017] There is therefore the need to perfect a coffee machine that can overcome at least one of the disadvantages of the state of the art. To do this, it is necessary to solve the technical problem of effectively decoupling the grinding device from the surrounding components so as to prevent any noise from propagating to the outside.

[0018] In particular, one purpose of the present invention is to provide a “silent” coffee machine, that is, a coffee machine having a lower noise emission so as not to create discomfort for users.

[0019] Another purpose of the present invention is to provide a machine that has a low acoustic impact regardless of the grinding device’s speed.

[0020] A further purpose of the present invention is to provide a coffee machine that limits the propagation of the vibrations and any noise generated by the grinding device.

[0021] A further purpose of the present invention is to provide a coffee machine that improves the preservation of the hopper’s coffee beans compared to what is known in the prior art.

[0022] A further purpose of the invention is to soundproof a coffee machine simply and effectively.

[0023] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

[0024] SUMMARY OF THE INVENTION

[0025] The present invention is set forth and characterized in the independent claim. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0026] In accordance with the above purposes and to solve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a coffee machine according to the present invention comprises:

[0027] - a grinding device;

[0028] - a hopper able to contain coffee beans and provided at the lower part with an outlet aperture for the beans which is located above the grinding device;

[0029] - a containing body comprising a compartment provided with a housing zone for the grinding device and a housing zone for the hopper, wherein the coffee machine comprises an annular decoupling gasket disposed between the outlet aperture of the hopper and a loading aperture of the grinding device, wherein the decoupling gasket is made of a soft material having a Shore A hardness lower than or equal to 35.

[0030] This achieves at least the advantage that the decoupling gasket is able to flex when subjected to a force, allowing to decouple the two components effectively and prevent the vibrations generated by the grinding device from propagating toward the hopper. It is thus possible to also use lightweight hoppers, which are not suitable to withstand the forces generated during the operation of the grinding device.

[0031] In particular, the decoupling gasket is able to absorb the kinetic energy of the beans, or bean fragments, which are thrown against it by the rotation of the grinding device. The centrifugal force acting on the components creates high-speed particles that impact the hopper’s walls, generating noise, and the present solution aims to slowly reduce the momentum of these particles so as to avoid impulsive noise. The resulting effect is a reduction in the overall noise of the grinding process.

[0032] In accordance with one aspect of the invention, the decoupling gasket is made of a soft material having a Shore A hardness comprised between 30 and 35. Unless otherwise indicated, the extremes are to be considered as included.

[0033] Suitable soft materials for the decoupling gasket are, for example, thermoplastic elastomers (TPEs), silicone, butyl rubber, EPDM (Ethylene-Propylene Diene Monomer), natural rubber.

[0034] According to one aspect of the invention, at the upper part the decoupling gasket is shaped as an inverted “C”, with cavity open upward, able to deform and collapse under the action of forces acting thereon, comprising an intermediate portion able to be disposed, during use, between a lower edge of the hopper delimiting the outlet aperture and an upper edge of a stationary portion of the grinding device, and respective free ends which are able to bend.

[0035] In the back of the “C” shape, that is, in the intermediate portion, a through hole is provided that reciprocally connects the hopper and the loading aperture.

[0036] According to one aspect of the invention, the decoupling gasket has a ratio of maximum thickness to height comprised between 1 :4.5 and 1:5.

[0037] According to one aspect of the invention, the decoupling gasket is configured to engage at the lower part with a stationary portion of the grinding device and at the upper part with a lower portion of the hopper, so as to be free to rotate around the rotation axis.

[0038] According to another aspect of the invention, the decoupling gasket is disposed with clearance between the hopper and the grinding device.

[0039] Preferably, a gap, that is, an empty space, is provided between the decoupling gasket and at least one of either the grinding device or the hopper. This allows to achieve an effective coupling between grinding device and hopper, considerably reducing any noise.

[0040] According to another aspect of the invention, the decoupling gasket is configured to be free to move in a direction of rotation with respect to a rotation axis of the grinding device.

[0041] The decoupling gasket has a height able to absorb the kinetic energy of the beans dragged in rotation by the grinding device.

[0042] According to one aspect of the invention, the decoupling gasket’s height is comprised between 10 mm and 15 mm.

[0043] According to another aspect of the invention, the decoupling gasket’ s thickness is comprised between 2 mm and 3 mm.

[0044] According to another aspect of the invention, the decoupling gasket comprises an intermediate portion, preferably with a truncated cone shape, able to be disposed, during use, between a lower edge of the hopper delimiting the outlet aperture and an upper edge of the stationary part of the grinding device. This intermediate portion substantially defines the back of the “C” shape.

[0045] According to another aspect of the invention, the decoupling gasket comprises an upper lip, which defines the free ends of the inverted “C” shape, configured to be inserted into a receiving seating defined between two circular rings created on the hopper.

[0046] According to one aspect of the invention, the circular rings can be substantially coaxial to the outlet aperture.

[0047] According to one aspect of the invention, an internal circular ring can define the peripheral edge of the outlet aperture.

[0048] According to one aspect of the invention, the upper lip has a thickness comprised between 0.4 and 0.6 times an amplitude of the receiving seating, thus having sufficient clearance to be able to move in the direction of rotation.

[0049] According to one aspect of the invention, there is a gap having an inverted “U” shape between the upper lip and the receiving seating, able to prevent the dispersion of the powder during the grinding process.

[0050] According to another aspect of the invention, the decoupling gasket comprises a protruding lower lip able to cooperate with the grinding device’s loading aperture.

[0051] According to another aspect of the invention, the upper lip and the lower lip extend substantially parallel to each other from opposite sides of the truncated conical portion.

[0052] According to another aspect of the invention, the decoupling gasket comprises a circumferential tooth that extends around the upper lip and defines an annular notch therewith.

[0053] According to another aspect of the invention, the lower lip comprises, on the surface facing inward, a recess, defined between the truncated conical portion and a widened terminal part.

[0054] The recess and / or the widened terminal part are able to engage by same-shape coupling with, respectively, a protruding portion and a notch which are created on the stationary portion of the grinding device.

[0055] According to another aspect of the invention, the intermediate portion has a truncated cone shape with a diameter decreasing from the upper lip toward the lower lip.

[0056] According to another aspect of the invention, the truncated conical portion has a thickness decreasing between the upper lip and the lower lip.

[0057] According to another aspect of the invention, the decoupling gasket has a variable rigidity along its height, with greater flexibility in correspondence with the free ends of the upper lip and lower lip compared to the intermediate portion.

[0058] According to another aspect of the invention, the decoupling gasket has a compact annular configuration concentrated in an interface area between the outlet aperture and has a height comprised between 10 mm and 15 mm.

[0059] In accordance with one aspect of the present invention, the hopper comprises a closing lid made of soft and flexible material, that is, a material able to absorb and dampen any vibrations acting thereon. In accordance with another aspect of the present invention, the lid comprises a protruding tooth able to engage in a groove provided on a lateral wall of the hopper. This guarantees the sealed closure of the hopper, which is necessary to reduce the propagation of noise through the air.

[0060] According to another aspect of the invention, the coffee machine comprises a duct for feeding coffee powder, closed at the upper part by a covering element provided with slits for the passage of water vapor, and the lid is provided with slots disposed, during use, aligned with the slits, and an annular packing is provided between the lid and the covering element which surrounds the space between the slits and the slots.

[0061] According to another aspect of the invention, the coffee machine comprises an adjustment device operable by a user to change the coffee powder’s granulometry, comprising a knob connected by means of a stem to a translation mechanism able to move a stationary portion with respect to a rotating portion of the grinding device, wherein the stem is disposed passing through a hole created on an internal wall of the hopper, and a damping packing is disposed between the knob and the hopper.

[0062] DESCRIPTION OF THE DRAWINGS

[0063] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

[0064] - fig. 1 is a partial schematic view of a coffee machine according to the present invention;

[0065] - fig. 2 is a section view of a grinding assembly of the machine of fig. 1 along line II-II;

[0066] - fig. 3 is an enlarged view of detail A of fig. 2;

[0067] - fig. 4 is an enlarged view of detail A of fig. 2 according to a variant;

[0068] - fig. 5 is an enlarged view of detail B of fig. 2;

[0069] - fig. 6 is a section view of the grinding assembly along line VI- VI of fig. 1 ;

[0070] - fig. 7 is an enlarged view of detail C of fig. 6;

[0071] - fig. 8 is a section view of the grinding assembly along line VIII- VIII of fig. 10;

[0072] - fig. 9 is an enlarged view of detail D of fig. 8;

[0073] - fig. 10 is a partial top view of the machine of fig. 1 ; - fig. 11 is a three-dimensional top view of the grinding assembly of the coffee machine of fig. 1 , in which the lid has been removed.

[0074] We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0075] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

[0076] With reference to fig. 1, a coffee machine 10 according to the present invention comprises:

[0077] - a grinding device 11 ;

[0078] - a hopper 12 able to contain coffee beans and provided at the lower part with an outlet aperture 13 for the beans, disposed above the grinding device;

[0079] - a containing body 14 comprising a compartment 15 provided with a housing zone for the grinding device 11 and a housing zone for the hopper 12.

[0080] The coffee machine 10 can also comprise, in a known manner, a brewing unit 34 and a nozzle 35 for delivering the beverage.

[0081] According to one aspect of the invention, the coffee machine 10 comprises a decoupling gasket 16 (fig. 2) disposed between the outlet aperture 13 of the hopper 12 and a loading aperture 17 of the grinding device 11.

[0082] According to one aspect of the invention, the decoupling gasket 16 is made of a soft material having a Shore A hardness lower than or equal to 35.

[0083] Preferably, the decoupling gasket 16 is made of a soft material having a Shore A hardness comprised between 30 and 35.

[0084] The decoupling gasket 16 is made of soft material, able to deform and / or compress, which can be chosen from thermoplastic elastomers (TPE), silicone, butyl rubber, EPDM (Ethylene-Propylene Diene Monomer), natural rubber.

[0085] The grinding device 11 comprises, in a known manner, a stationary portion 18 and a rotating portion 19, that is, at least one of the grinders, which is connected to a drive member 20.

[0086] The stationary portion 18 can comprise a first fixed part 18a and a second movable part 18b, configured to move in an axial direction relative to the rotating portion 19 and to the first part 18a, so as to adjust the coffee powder’s granulometry.

[0087] According to one aspect of the invention, the decoupling gasket 16 is configured to engage with the stationary portion 18 of the grinding device 11 at the lower part, and with a lower portion of the hopper 11 at the lower part.

[0088] According to one aspect of the invention, the decoupling gasket 16 is disposed with clearance between the hopper 12 and the grinding device 11, and preferably a gap 56, 57, that is, a free air space, is provided between at least one of these and the decoupling gasket 16.

[0089] According to one aspect of the invention, the decoupling gasket 16 is engaged with at least one of either the hopper 12 or the grinding device 11, so as to be free to move in a direction of rotation around the rotation axis X.

[0090] At the upper part, the decoupling gasket 16 can be shaped as an inverted “C”, with the cavity open upward. In the back of the “C” shape, there is provided a through hole 16a that reciprocally connects the outlet aperture 13 of the hopper 12 and the loading aperture 17.

[0091] The decoupling gasket 16 is able to engage externally with the edge delimiting the outlet aperture 13, and internally with an upper edge 21 of the stationary portion 18 surrounding the loading aperture 17.

[0092] The decoupling gasket 16 is disposed with clearance between the respective edges of the outlet and loading apertures 13 and 17.

[0093] The decoupling gasket 16 has a height Hl (fig. 3) able to absorb the kinetic energy of the beans dragged in rotation by the grinding device 11.

[0094] The height Hl can be comprised between 10 mm and 15 mm.

[0095] The decoupling gasket 16 can have a ratio of maximum thickness S to height Hl comprised between 1:4.5 and 1 :5.

[0096] The maximum thickness S can be comprised between 2 mm and 3 mm.

[0097] The decoupling gasket 16 can have a compact conformation, such that a ratio of its height Hl to a maximum diameter thereof is comprised between 0.20 and 0.35, preferably between 0.25 and 0.30. With reference to figs. 2 and 3, the decoupling gasket 16 comprises an intermediate portion 22, preferably with a truncated cone shape, able to be disposed, during use, between a lower edge of the hopper 12 delimiting the outlet aperture 13 and an upper edge of the loading aperture 17, which substantially defines the back of the “C” shape.

[0098] The decoupling gasket 16 also comprises an upper lip 23 having a substantially cylindrical shape, configured to be inserted into a receiving seating 25 of the hopper 12, wherein the upper lip 23 defines the free ends of the “C” shape.

[0099] The upper lip 23 extends in continuity with the truncated conical portion 22.

[0100] The decoupling gasket 16 can have a maximum thickness S between the zone in which the upper lip 23 and the truncated conical portion 22 join, and the opposite side of the upper lip 23.

[0101] The decoupling gasket 16 comprises a protruding lower lip 24 able to be inserted in the aperture 26 delimited by the upper edge 21 of the grinding device 11. In particular, the lower lip 24 can be at least partly disposed above the edge delimiting the loading aperture 17.

[0102] The upper lip 23 and the lower lip 24 extend substantially parallel to each other on opposite sides of the truncated conical portion 22.

[0103] The lower lip 24 can comprise, on the surface facing inward, a recess 27.

[0104] The recess 27 is able to receive and engage with a protruding portion 58 created on a component of the stationary portion 18 of the grinding device 11.

[0105] An example of this embodiment is shown in fig. 4.

[0106] The lower lip 24 can also comprise a widened terminal part 29, that is, having a thickness greater than a thickness of the remaining part of the lower lip 24, able to engage in a notch 59 provided on the component of the stationary portion 18, creating a same-shape coupling.

[0107] The stationary portion 18 can also comprise an abutment element 60 on which the lower lip 24 can be disposed resting.

[0108] According to this variant, essentially only the gap 56 between the upper lip 23 and the hopper 12 is present.

[0109] The lower lip 24 can be offset with respect to a free end 28 of the truncated conical portion 22, and the recess 27 can be defined between that end 28 and the widened terminal part 29 of the lower lip 24. The decoupling gasket 16 can also comprise a circumferential tooth 30, which extends around the upper lip 23 on the opposite side with respect to the truncated conical portion 22 and defines, together with the upper lip 24, an annular notch 31 open at the upper part.

[0110] Preferably, the truncated conical portion 22 can have a height H2 comprised between 0.2 and 0.4 times the height Hl, able to adapt to a possible movement of the second part 18b in an axial direction.

[0111] According to one aspect of the invention, the intermediate truncated conical portion 21 has a thickness decreasing between the upper lip 23 and the free end 28.

[0112] With reference to figs. 2 and 3, the receiving seating 25 can be defined between two circular rings 32, 33 created on the hopper 12.

[0113] The circular rings 32, 33 are substantially coaxial to the outlet aperture 13. In particular, an internal circular ring 32 can define the peripheral edge of the outlet aperture 13 and the external circular ring 33 is located spaced apart around it.

[0114] According to one aspect of the invention, the upper lip 23 can have a thickness SI comprised between 0.4 and 0.6 times an amplitude W of the receiving seating 25.

[0115] The hopper 12 can be hermetically closed at the upper part by a lid 40, preferably made of soft material, in particular a low density material, able to absorb and dampen any vibrations acting thereon, reducing the propagation of noise through the air. This solution avoids co-injection processes that are unsustainable and expensive.

[0116] With reference to figs. 2 and 5, the lid 40 is able to couple to an external part of the hopper 12.

[0117] The lid 40 can comprise a protruding tooth 41 able to engage in a groove 42 which is provided on an external lateral wall 43 of the hopper 12 so as to guarantee the seal.

[0118] The lid 40 can comprise a handle 43 by means of which a user can remove the lid 40.

[0119] To facilitate opening, the lid 40 can also comprise one or more convex protrusions 44, four in the example given, which a user can press with their fingers while acting on the handle 43 with their thumb, so as to allow air to pass between the lid 40 and the hopper 12. Figs. 6 and 7 show a view along section line VI- VI of fig. 1, in which an adjustment device 36 of the coffee machine 10 is visible, operable by a user to modify the distance between the stationary portion 18, in particular the second part 18b thereof, and the rotating portion 19, and thus the size of the ground coffee powder.

[0120] According to one aspect of the invention, the adjustment device 36 comprises a knob 37 connected to a translation mechanism 39 by means of a stem 38. The rotation of the knob 37 in either direction results in a rotation of the translation mechanism 39 which moves the second part 18b in a direction parallel to the axis X. The translation mechanism 39 and the movable second part 18b can be provided with respective toothed wheels 45 or toothed portions 46 able to engage with each other.

[0121] The stem 38 is disposed passing through a hole 47 created on an internal wall 48 of the hopper 12. The internal wall 21 can define the space for containing the beans and can be shaped so as to define a cavity 49 below it, able to accommodate the stem 38.

[0122] According to one aspect of the invention, between the knob 37 and the internal wall 48 around the hole 47 there is provided a damping packing 50 able to prevent intermittent contact between the hopper 12 and the knob 37, and thus prevent the transmission of vibrations.

[0123] Fig. 8 shows the hopper 12 according to section line VIII- VIII indicated in fig. 10. This drawing shows a duct 51 for feeding coffee powder, through which it is possible to supply a dose of powder to the brewing unit 34 without passing through the grinding device 11.

[0124] The duct 51 can be closed at the upper part by means of a covering element 52 provided with slits 53 for the passage of water vapor.

[0125] The lid 40 can in turn be provided with respective slots 54 disposed, during use, aligned with the slits 53.

[0126] In order to guarantee that the water vapor is properly dispersed through these slots 54, an annular packing 55 is provided between the lid 40 and the covering element 52 which surrounds the area occupied by the slits 53 and slots 54.

[0127] The view of fig. 11 shows, disposed inside the hopper 12, both the knob 37 of the adjustment device 36 and also the covering element 52 that closes the duct 51 for the coffee powder.

[0128] It is clear that modifications and / or additions of parts may be made to the coffee machine 10 as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims. It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of low acoustic impact coffee machines, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby. In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

CLAIMS1. Coffee machine (10) comprising:- a grinding device (11);- a hopper (12) able to contain coffee beans and provided at the lower part with an outlet aperture (13) for the beans which is disposed above said grinding device (H);- a containing body (14) comprising a compartment (15) provided with a housing zone for said grinding device (11) and a housing zone for said hopper (12), characterized in that said coffee machine (10) comprises an annular decoupling gasket (16) disposed between said outlet aperture (13) of said hopper (12) and a loading aperture (17) of said grinding device (11) and made of a soft material having a Shore A hardness lower than or equal to 35.

2. Coffee machine (10) as in claim 1 , characterized in that said decoupling gasket (16) is made of a soft material having a Shore A hardness comprised between 30 and 35.

3. Coffee machine (10) as in claim 1 or 2, characterized in that at the upper part said decoupling gasket (16) is shaped as an inverted “C”, with cavity open upward, comprising an intermediate portion (22) able to be disposed, during use, between a lower edge (32) of said hopper (12) delimiting said outlet aperture (13) and an upper edge (21) of a stationary portion (18) of said grinding device (11) and respective free ends which are able to bend.

4. Coffee machine (10) as in claim 3, characterized in that said decoupling gasket (16) comprises an upper lip (23) configured to be inserted into a receiving seating (25) defined between two circular rings (32, 33) created on said hopper (12), and a lower lip (24) able to cooperate with said loading aperture (17), wherein said upper lip (23) and said lower lip (24) extend substantially parallel to each other from opposite sides of the intermediate portion (22).

5. Coffee machine (10) as in claim 4, characterized in that said upper lip (23) has a thickness (SI) comprised between 0.4 and 0.6 times an amplitude (W) of said receiving seating (25).

6. Coffee machine (10) as in one or other of the previous claims, characterized in that said decoupling gasket (16) has a ratio of maximum thickness (S) to height (Hl) comprised between 1:4.5 and 1:5.

7. Coffee machine (10) as in one or other of the previous claims from 3 to 6, characterized in that said lower lip (24) comprises, on the surface facing inward, a recess (27), defined between said intermediate portion (22) and a widened terminal part (29) of the lower lip (24), able to receive and engage with a protruding portion (58) created on a component of a stationary portion (18) of said grinding device (11).

8. Coffee machine (10) as in any claim from 5 to 7 when dependent on claim 3 or 4, characterized in that said intermediate portion (22) has a truncated cone shape with a diameter decreasing from said upper lip (23) toward said lower lip (24).

9. Coffee machine (10) as in any claim from 5 to 8 when dependent on claim 3 or 4, characterized in that said intermediate portion (22) has a thickness decreasing between said upper lip (23) and said lower lip (24).

10. Coffee machine (10) as in any claim from 5 to 9 when dependent on claim 3 or 4, characterized in that said decoupling gasket (16) has a variable rigidity along its height (Hl), with greater flexibility in correspondence with the free ends compared to the intermediate portion (22).

11. Coffee machine (10) as in one or other of claims from 4 to 10 when dependent on claim 3, characterized in that said decoupling gasket (16), by elastic deformation of its inverted “C” shape, is configured to absorb the kinetic energy of coffee beans or coffee bean fragments which are thrown by a rotation of said grinding device (11).

12. Coffee machine (10) as in any claim hereinbefore, characterized in that said decoupling gasket (16) is disposed with clearance between said hopper (12) and said grinding device (11), and at least a gap (56, 57) is provided between said decoupling gasket (16) and at least one of either said grinding device (11) or said hopper (12).

13. Coffee machine (10) as in one or other of the previous claims, characterized in that said coffee machine (10) comprises a closing lid (40) able to close said hopper (12) at the upper part, wherein said lid (40) is made of soft and flexible material and comprises a protruding tooth (41) able to engage in a groove (42) provided on a lateral wall (43) of said hopper (12).

14. Coffee machine (10) as in claim 13, characterized in that said coffee machine (10) comprises a duct (51) for feeding coffee powder closed at the upper part by acovering element (52) provided with slits (53) for the passage of water vapor, and said lid (40) is provided with slots (54) disposed, during use, aligned with said slits (53), wherein an annular packing (55) is provided between said lid (40) and said covering element (52) which surrounds the space between said slits (53) and said slots (54).

15. Coffee machine (10) as in any claim hereinbefore, characterized in that it comprises an adjustment device (36) drivable by a user to change the coffee powder’s granulometry, comprising a knob (37) connected by means of a stem (38) to a translation mechanism (39) able to move a stationary portion (18) with respect to a rotating portion (19) of said grinding device (11), wherein said stem (38) is disposed passing through a hole (47) created on an internal wall (48) of said hopper (12), and a damping packing (50) is disposed between said knob (37) and said hopper (12).

16. Coffee machine (10) as in any claim hereinbefore, characterized in that said decoupling gasket (16) has a compact annular configuration concentrated in an interface area between said outlet aperture (13) and has a height (Hl) comprised between 10 mm and 15 mm.

17. Coffee machine (10) as in any claim hereinbefore, characterized in that said decoupling gasket (16) is configured to move freely in a direction of rotation around a rotation axis (X) of said grinding device (11) without transmitting any torsional torque between said hopper (12) and said grinding device (11).

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