Coffee grinding machine with grinding disc alignment system and related methods

Abstract

A coffee grinding machine is described, the machine comprising: a first grinding disc; a motor configured to rotate the first grinding disc about a rotation axis; a second grinding disc configured to cooperate with the first grinding disc for grinding coffee beans wherein the second grinding disc comprises a second surface, preferably extending substantially along an outer edge of the second grinding disc, i.e. Near the outer edge of the first grinding disc; a grinder holder body that can be locked to the second grinding disc, where the grinder holder body includes a first surface at least partially facing and mating with the second surface, where one of the first surface and the second surface is a spherical surface, where the other of the first surface and the second surface is a spherical surface, and wherein the first surface and the second surface cooperate with each other to appropriately orient the first abrasive disc relative to the second abrasive disc prior to locking the second abrasive disc to the grinder holder body.

Description

Technical Field

[0001] The present invention relates to a machine for grinding coffee beans. The machine for grinding coffee beans can be a separate machine or can be incorporated in a machine for producing coffee-based beverages. Such a machine is also referred to as a "coffee grinding machine", "coffee grinder" or "milling machine" for short.

[0002] More particularly, the invention relates to a coffee grinding machine, wherein the grinding of the coffee beans is at least partially performed by a flat burr. Even more particularly, the invention relates to a coffee grinding machine with a system for aligning the burr, i.e. for making the burr parallel, and to a method for aligning the burr, i.e. making the burr parallel, of a flat burr coffee grinding machine. Background Art

[0003] As is well known, in order to prepare espresso, a certain amount of ground coffee is used, usually referred to as a dose. The dose can be a single dose, a double dose or a multi-dose. The dose of ground coffee is filled into a filter, which is usually in the form of a cup with an open top and micro-perforated bottom. Usually, the dose of coffee is pressed into the filter so as to form a coffee cake. The filter is in turn supported by a filter holder, which is configured to be removably engaged with a dispensing unit of an espresso machine. Espresso is obtained by passing hot water under pressure through the coffee cake.

[0004] Coffee powder is obtained by means of a coffee grinding machine. In known coffee grinding machines, coffee beans are ground by passing them through grinding members. Flat, conical or mixed grinding members are known. Usually, the grinding members of a coffee grinding machine comprise a fixed member and a member that rotates relative to the fixed member. For example, in a coffee grinding machine with flat grinding discs, one grinding disc remains stationary, i.e. fixed, while the other grinding disc is rotated by a motor. Some coffee grinding machines are able to modify the distance between the grinding discs in order to change the particle size of the coffee powder.

[0005] US 4,037,798 A describes a machine with a flat grinder for grinding cereals. Summary of the invention

[0006] According to the applicant, the main goal of the manufacturers of coffee grinding machines (with flat and conical grinding discs) is to obtain a particle size that is reproducible and constant over time, characterized by a master curve that is as limited as possible. The purpose of this is to obtain a similar water exchange area for all powder particles and therefore a similar solute extraction response for most particles.

[0007] The applicant believes that in order to achieve this goal, the alignment of the grinding discs plays a crucial role. In fact, if the grinding discs are aligned, the powder outlet opening has the same height along the entire periphery of the two grinding discs. On the other hand, if the grinding discs are not aligned, the outlet openings have different heights and the particle size of the powder is also different.

[0008] Furthermore, applicants believe that the overall stability of the motion mechanical system during operation is also very important, including during the necessary steps of adjusting the particle size.

[0009] The applicant believes that when the alignment of the grinding disc is not optimal, some very fine particle types cannot be obtained. For example, those particle sizes suitable for extracting Turkish coffee cannot be obtained. In any case, non-optimal particle sizes lead to a decrease in the quality of the beverage obtained.

[0010] The applicant has found that machines with flat grinding discs require very precise horizontal alignment due to their construction. In fact, the cutting edge extends along the horizontal component as well as the grinding flow direction extending radially. In other words, it is preferred that the flat grinding discs should be completely parallel to each other.

[0011] The Applicant has noted that the fixed upper millstone 18 of the grain milling machine described in US 4,037,798 A is constrained to the cylindrical container 10 and has no degree of freedom, i.e. has a rigidly fixed position relative to the cylindrical container 10. In contrast, the rotatable lower millstone can be elastically pivoted and its position is dynamically adjusted. This solution does not ensure a precise alignment of the millstones.

[0012] According to the invention, the problem of precise alignment of a flat grinding disc in a coffee grinding machine is solved by a shaped connection between the grinder holder body and the fixed grinding disc. The shaped connection is preferably a connection achieved by a curved surface, such as a spherical surface or a substantially spherical surface.

[0013] According to a first aspect, the present invention provides a coffee grinding machine with a flat grinding disc, comprising:

[0014] a first grinding disc;

[0015] a motor configured to rotate the first grinding disk about a rotation axis;

[0016] a second grinding disk configured to cooperate with the first grinding disk for grinding coffee beans, wherein the second grinding disk comprises a second surface;

[0017] a grinder holder body that can be locked to the second grinding disc, wherein the grinder holder body comprises a first surface that at least partially faces the second surface and cooperates therewith,

[0018] wherein one of the first surface and the second surface is a spherical surface,

[0019] wherein the other of the first surface and the second surface is a spherical surface, or includes a conical surface, or includes a serrated surface, or includes a deformable element, and

[0020] Wherein the first surface and the second surface cooperate with each other to properly orient the first grinding disk relative to the second grinding disk prior to locking the second grinding disk to the grinder holder body.

[0021] According to an embodiment, the second surface extends substantially along an outer edge of the second grinding wheel, ie in the vicinity of an outer edge of the first grinding wheel.

[0022] According to an embodiment, the first surface is a spherical surface and the second surface is a spherical surface, such that there is a surface contact between the first surface and the second surface.

[0023] According to an embodiment, the second surface is a spherical surface and the first surface is a conical surface, or the second surface is a conical surface and the first surface is a spherical surface, such that contact is provided along a line between the first surface and the second surface.

[0024] According to an embodiment, the first surface is a serrated first surface and the second surface is a spherical surface, such that contact along one or more lines is provided between the first surface and the second surface.

[0025] According to an embodiment, the first surface comprises a deformable element and the second surface is a spherical surface, such that a resilient contact is provided between the grinder holder body and the second grinding disk.

[0026] According to an embodiment, the grinder holder body may be releasably associated with the second grinding disc by means of a connection member, such as a clamping screw.

[0027] According to an embodiment, the coffee grinding machine further comprises an element allowing to partially support the connecting member.

[0028] According to an embodiment, the element comprises a conical spring washer or a conical Type safety washer.

[0029] According to another aspect, there is provided a method for orienting grinding disks relative to each other in a flat grind disk coffee grinding machine, the method comprising:

[0030] - Provide coffee grinding machine, including:

[0031] a first rotatable grinding disc;

[0032] a second grinding disk configured to cooperate with the first grinding disk for grinding coffee beans, wherein the second grinding disk comprises a second surface;

[0033] a grinder holder body releasably associable with the second grinding disc, wherein the grinder holder body includes a first surface at least partially facing and cooperating with the second surface,

[0034] wherein one of the first surface and the second surface is a spherical surface, and wherein the other of the first surface and the second surface is a spherical surface, or comprises a conical surface, or comprises a serrated surface, or comprises a deformable element,

[0035] - orienting the second grinding disc relative to the first grinding disc, and

[0036] - locking the second grinding disc to the grinder holder body, wherein the orienting step comprises moving the second grinding disc and the grinder holder body relative to each other along the first surface and the second surface, and a step for releasably associating the second grinding disc and the grinder holder body is performed after the orienting step.

[0037] According to an embodiment, the second surface extends substantially along an outer edge of the second grinding wheel, ie in the vicinity of an outer edge of the first grinding wheel.

[0038] According to an embodiment, the orienting step comprises orienting the second grinding disk relative to the first grinding disk such that the first grinding disk is parallel to the second grinding disk.

[0039] According to an embodiment, the facing curved surface comprises a spherical surface.

[0040] The first grinding disk may include a first planar surface on its outer edge, and the second grinding disk may include a second planar surface on its outer edge, and wherein the orienting step includes the step of moving the second grinding disk close to the first grinding disk so that the first planar surface and the second planar surface are aligned with each other.

[0041] According to an embodiment, the second grinding disc is releasably locked to the grinder holder body after the first planar surface and the second planar surface are arranged parallel to each other.

[0042] According to an embodiment, the second grinding disc is connected by means of a screw and an optional conical spring washer or A type safety washer is releasably locked to the grinder holder body. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The following is a detailed description of the present invention, which is provided by way of non-limiting example only and is to be read with reference to the accompanying drawings, in which:

[0044] Figure 1.1 A schematic diagram of a coffee grinding machine with a flat grinding disc according to an embodiment of the present invention;

[0045] Figure 1.2 for Figure 1.1 A longitudinal section view of the machine shown in ;

[0046] Figure 2 for Figure 1.2 An enlarged isometric schematic view of the grinding disc of the machine shown in ;

[0047] Figure 3 for Figure 1.2 An enlarged longitudinal cross-sectional view of the grinding disc of the machine shown in ;

[0048] Figure 4 for Figure 3 An exploded view of a detail of the grinding disc assembly shown in;

[0049] Figure 5 and 6 Two exploded cross-sectional views of the grinding disc assembly;

[0050] Figure 7.1 and 7.2 is an enlarged view of two parts of a connection with double spherical contact between a fixed grinding disc and a grinder holder;

[0051] Figure 8.1 and 8.2 is an enlarged view of two parts of the connection between the fixed grinding disc and the grinder holder with a ball / cone connection;

[0052] Figure 9.1 and 9.2 An enlarged view of two parts of the connection between a fixed grinding disc and a grinder holder with a serrated surface and a spherical surface; and

[0053] Figure 10.1 and 10.2 Magnified view of the two parts of the connection between the fixed grinding disc and the grinder holder with the spherical surface and the deformable element. DETAILED DESCRIPTION

[0054] Figure 1.1 and 1.2A coffee grinding machine according to an example of an embodiment of the invention is shown. Obviously, the coffee grinding machine according to the invention may take forms completely different from those shown, without departing from the scope of protection of the invention.

[0055] The machine 10 includes a machine body 12 that houses the main components, including a grinding chamber with a grinding disc assembly 30. Generally, the machine 10 includes a hopper 14 in its top portion. The hopper 14 is configured to receive coffee beans to be ground and allow the coffee beans to reach the grinding chamber and the grinding disc assembly 30.

[0056] The machine 10 may also include a device 15 for adjusting the fineness of the ground powder, such as Figure 1.1 Knurled ring nut shown in .

[0057] The machine 10 further comprises an outlet duct 16 for directing the ground coffee towards a filter 18, which in turn is supported by a filter holder 20. Advantageously, a support 22 may be provided for supporting the filter holder 20 during the filling of the filter 18 with the ground coffee powder. The height of the support 22 may be adjusted. Figure 1.1 In the figure, buttons 26 for operating the coffee grinding machine can also be seen, as well as light-emitting diodes (or displays) for displaying the status of the machine 10.

[0058] Figure 1.2 Show according to Figure 1.1 In addition to the components already mentioned, it also shows a grinding disc assembly 30 and an electric motor 24 for rotating one grinding disc relative to the other.

[0059] In each Figure 2-6 The grinding disc assembly 30 is shown in more detail in FIG.

[0060] each Figure 2-6 Also shown is a grinding chamber with a grinding wheel assembly 30 which in turn comprises a lower grinding wheel 2 and an upper grinding wheel 3 .

[0061] According to the embodiment shown, the lower grinding disc 2 is a movable grinding disc. The lower grinding disc 2 is kinematically connected to the motor shaft in any known manner. For example, the connection can be achieved by a grinder holder flanged disc 1 that rotatably supports the lower grinding disc 2.

[0062] Advantageously, the flanged disc 1 may be provided with a suitable radial profile 2a suitable for discharging the ground coffee from the grinding discs 2, 3 of the grinding chamber.

[0063] It is obvious that in the present description and the associated figures, the arrangement of the axes AA of the grinding discs 2, 3 is vertical. However, the invention is also applicable to coffee grinding machines with grinding disc axes that are horizontal or differently inclined relative to the vertical. Figure 1.2 As shown in , the axis AA of the grinding disc is inclined relative to the vertical. The grinding discs can also be arranged differently, so as to have a movable grinding disc at the top, or to have two movable grinding discs.

[0064] The upper grinding disc 3 is aligned on said axis AA. For the reasons mentioned above, the upper grinding disc 3 must be completely parallel to the lower grinding disc 2. The upper grinding disc 3 is fixed to a threaded grinder holder element 4 which determines the adjustment of the grinding via the relative axial spacing of the grinding discs 2 and 3 by means of a specifically defined thread pitch and a ring nut 15.

[0065] For the purposes of this specification and the claims, the expression "the plane of the (flat) grinding disc" or similar expressions shall mean the plane defined when the grinding disc rests on a horizontal surface. The plane of the grinding disc also corresponds to the plane in which the outer periphery of the outer edge of the grinding disc lies, near the outlet.

[0066] For the purposes of the present description and the claims, the expression "aligning the grinding discs" shall mean appropriately orienting two cooperating flat grinding discs relative to each other such that the plane of one grinding disc is parallel to the plane of the other grinding disc.

[0067] For the purposes of the present description and the claims, the expression "spherical surface" will indicate a surface corresponding to a portion of a sphere. The expression will indicate both concave sphere portions and convex sphere portions.

[0068] For the purposes of the present description and the claims, the expression "conical surface" will indicate a surface corresponding to a portion of a frustum of a cone.

[0069] Axial grinding adjustment is performed indirectly. Thus, during adjustment, the threaded grinder holder body 4 and the upper grinding disc 3 fixed thereto are not rotated by means of suitable radial positioning elements 11 but are moved vertically by means of rotation of the ring nut 15 .

[0070] According to an embodiment, the play generated by the engagement between the thread of the ring nut 15 and the grinder holder element 4 is absorbed by the axial spring 6, the thrust of which acts in the direction of the grinding thrust.

[0071] In known coffee grinding machines, the flat grinding disc is usually coupled to the grinder holder element by a planar surface perpendicular to its axis.

[0072] According to the present invention, a configuration is provided in which the fixed upper grinding disc 3 "floats" relative to the grinder holder body 4 before being firmly clamped to the grinder holder body 4. According to one embodiment, this function is ensured by special spherical processing, that is, a spherical surface 3a extending along the outer edge of the fixed grinding disc 3. The spherical surface 3a is configured to couple with a spherical seat 4a formed on the grinder holder body 4.

[0073] The alignment (i.e. parallel arrangement) of the grinding discs 2, 3 is performed by bringing the two grinding discs into contact with each other via the adjustment ring nut 15. In other words, the fixed upper grinding disc 3 is moved close to the lower grinding disc 2 until the plane surfaces 2b and 3b on the outer edges in the undercut area of ​​the teeth are arranged completely aligned with each other. The floating coupling (before clamping) will be able to compensate for any alignment errors caused by the various components.

[0074] In this position, in which there is a substantially completely parallel arrangement, the upper grinding disc 3 is securely fixed, for example by a series of screws 8 positioned in the region of the spherical coupling rim 3a.

[0075] According to an embodiment, the clamping is performed gradually. It is recommended to tighten the screws 8 crosswise.

[0076] In order to compensate for any misalignment of a few micrometers under the head of the screw 8, an element allowing to partially support the screw can be used, such as a conical spring washer 9. For example, it is possible to use Type safety washer.

[0077] Once clamped, the upper grinding disc 3 will be arranged completely parallel to the lower grinding disc 2 and will remain in this state under any conditions of use and any adjustment settings for the coffee grinding machine.

[0078] As will become apparent, in order to automatically align (automatically parallelize) the grinding discs by means of a spherical coupling, two seats 3a and 4a, both spherical, are provided on both the upper grinding disc 3 and the grinder holder body 4. This type of coupling is also shown in the enlarged Figure 7.1 and 7.2 The grinder holder 4 has a spherical surface 4a, and the upper grinding disc has a corresponding spherical surface 3a.

[0079] However, variations of this embodiment are possible. These variations are also described in Figure 8.1 , 8.2 , 9.1, 9.2 and 10.1, 10.2.

[0080] According to the first variant ( Figure 8.1 and 8.2 ), the upper grinding disc 3 includes a spherical contact surface 3a, and the surface 4a directly facing the spherical contact surface 3a includes a conical surface.

[0081] Alternatively, according to a variant, the upper grinding disc 3 comprises a conical surface 3a, while the surface 4a directly facing the conical surface 3a comprises a spherical contact surface.

[0082] According to another variant ( Figure 9.1 and 9.2 ), the upper grinding disc 3 includes a spherical contact surface 3a, and the surface 4a directly facing the spherical contact surface 3a includes a serrated surface with two or more grooves. In this case, the contact between the spherical contact surface 3a and the surface 4a occurs along one of the peripheries corresponding to the groove lands.

[0083] According to another variant (essentially Figure 9.1 and 9.2 In contrast to the one shown in FIG. 1 , the upper grinding disc 3 comprises a serrated surface 3 a with two or more grooves, while the surface 4 a directly facing the serrated surface comprises a spherical surface. In this case, the contact between the serrated contact surface 3 a and the surface 4 a occurs along one of the peripheries corresponding to the groove lands.

[0084] According to another variant ( Figure 10.1 and 10.2 ), the upper grinding disc 3 comprises a spherical contact surface 3a, while the surface 4a directly facing the spherical contact surface 3a comprises a preferably elastically deformable body. This can be, for example, an elastomeric ring or the like which is partially inserted into a corresponding seat. The elastomeric ring can be designed to hold the grinding disc in position after appropriate pretensioning by means of a clamping screw.

[0085] Obviously, any reference to relative positions, such as "upper grinding disc" and "lower grinding disc", does not limit the purpose of the present invention. In other words, the upper grinding disc can be rotatable and the lower grinding disc can be fixed while still within the scope of protection of the present invention.

Claims

1. A coffee grinding machine (10) with a flat grinding disc, comprising: A first grinding disc (2); a motor (24) configured to rotate the first grinding disc (2) about a rotation axis (AA); a second grinding disc (3), the second grinding disc (3) being configured to cooperate with the first grinding disc (2) for grinding coffee beans, wherein the second grinding disc (3) comprises a second surface (3a); a grinder holder body (4) capable of being locked to the second grinding disc (3), wherein the grinder holder body (4) comprises a first surface (4a) at least partially facing the second surface (3a) and cooperating with the second surface, wherein one of the first surface (4a) and the second surface (3a) is a spherical surface, wherein the other of the first surface (4a) and the second surface (3a) is a spherical surface, or includes a conical surface, or includes a serrated surface, or includes a deformable element, and The first surface (4a) and the second surface (3a) cooperate with each other to properly orient the first grinding disc (2) relative to the second grinding disc (3) before locking the second grinding disc (3) to the grinder holder body (4).

2. The coffee grinding machine (10) according to claim 1, wherein: The second surface (3a) extends along the outer edge of the second grinding disc (3).

3. The coffee grinding machine (10) according to claim 1 or 2, wherein: The first surface is a spherical surface (4a) and the second surface is a spherical surface (3a) such that there is surface contact between the first surface and the second surface.

4. The coffee grinding machine (10) according to claim 1 or 2, wherein: The second surface (3a) is a spherical surface and the first surface is a conical surface (4a), or the second surface (3a) is a conical surface and the first surface is a spherical surface (4a), so that contact along a line is provided between the first surface and the second surface.

5. The coffee grinding machine (10) according to claim 1 or 2, wherein: The first surface is a first serrated surface (4a) and the second surface (3a) is a spherical surface such that contact along one or more lines is provided between the first surface and the second surface.

6. The coffee grinding machine (10) according to claim 1 or 2, wherein: The first surface comprises a deformable element and the second surface is a spherical surface so that a resilient contact is provided between the grinder holder body (4) and the second grinding disc (3).

7. The coffee grinding machine (10) according to claim 1, 2, 3, 4, 5 or 6, wherein: The grinder holder body (4) can be releasably associated with the second grinding disc (3) by means of a connection member such as a clamping screw (8).

8. Coffee grinding machine (10) according to claim 7, further comprising an element (9) allowing to partially support the connecting member.

9. The coffee grinding machine (10) according to claim 8, wherein: The element (9) comprises a conical spring washer (9) or a conical Type safety washer.

10. A method for orienting grinding discs (2, 3) relative to each other in a flat-grinding-disc coffee grinding machine, the method comprising: - providing a coffee grinding machine (10), comprising: A first rotatable grinding disc (2); a second grinding disc (3), the second grinding disc (3) being configured to cooperate with the first grinding disc (2) for grinding coffee beans, wherein the second grinding disc (3) comprises a second surface (3a); a grinder holder body (4) capable of being releasably associated with the second grinding disc (3), wherein the grinder holder body (4) comprises a first surface (4a) at least partially facing the second surface (3a) and cooperating with the second surface, wherein one of the first surface (4a) and the second surface (3a) is a spherical surface, and wherein the other of the first surface (4a) and the second surface (3a) is a spherical surface, or comprises a conical surface, or comprises a serrated surface, or comprises a deformable element, - orienting the second grinding disc (3) relative to the first grinding disc (2), and - locking the second grinding disc (3) to the grinder holder body (4), wherein an orienting step comprises moving the second grinding disc (3) and the grinder holder body (4) relative to each other along the first surface and the second surface, and a step for releasably associating the second grinding disc (3) and the grinder holder body (4) is performed after the orienting step.

11. The method according to claim 10, wherein: The second surface (3a) extends along the outer edge of the second grinding disc (3).

12. The method according to claim 10 or 11, wherein: The orienting step includes orienting the second grinding disc (3) relative to the first grinding disc (2) such that the first grinding disc (2) is parallel to the second grinding disc (3).

13. The method according to claim 10, 11 or 12, wherein: The facing curved surfaces include spherical surfaces.

14. The method according to any one of claims 10 to 13, wherein: The first grinding disc (2) includes a first planar surface (2b) on its outer edge, and the second grinding disc (3) includes a second planar surface (3b) on its outer edge, and wherein the orienting step includes the step of bringing the second grinding disc (3) close to the first grinding disc (2) until the first planar surface (2b) and the second planar surface (3b) are aligned with each other.

15. The method according to claim 10, wherein: After the first planar surface (2a) and the second planar surface (3a) are arranged parallel to each other, the second grinding disc (3) is releasably locked with the grinder holder body (4).

16. The method according to any one of claims 10 to 15, wherein: The second grinding disc (3) is secured by screws and optional conical spring washers (9) or A type safety washer is releasably locked to the grinder holder body (4).

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