Coffee grinding machine with bar alignment system and related method

Abstract

A coffee grinding machine is described, comprising: a first burr; a motor configured to rotate the first burr about an axis of rotation; a second burr configured to cooperate with the first burr to grind coffee beans, the second burr preferably having a second surface extending substantially along, i.e., near, an outer edge of the second burr; and a grinder holder body lockable to the second burr, the grinder holder body having a first surface at least partially facing the second surface and cooperating with the second surface, wherein one of the first and second surfaces is spherical and the other of the first and second surfaces is spherical, and the first and second surfaces cooperate with each other to properly orient the first burr relative to the second burr prior to locking the second burr to the grinder holder body.

Description

[Technical Field]

[0001] The present invention relates to a machine for grinding coffee beans, which can be a separate machine or can be integrated into a machine for producing coffee-based beverages, and such machines are also known simply as "coffee grinding machines", "coffee grinders" or "mills".

[0002] More particularly, the invention relates to coffee grinding machines in which the grinding of coffee beans is performed at least in part by flat burrs, and even more particularly to coffee grinding machines with a burr alignment or burr parallelization system and to a method for aligning or parallelizing the burrs of a flat burr coffee grinding machine. [Background technology]

[0003] As is known, a certain amount of ground coffee, commonly referred to as a "dose," is used to prepare espresso coffee. The dose can be a single dose, a double dose, or multiple doses. The dose of ground coffee is typically loaded into a filter in the form of a cup with an open top and a micro-perforated bottom. The dose of coffee is typically compressed within the filter to form a coffee powder pack. The filter is then supported by a filter holder configured to removably engage within the dispensing unit of an espresso coffee machine. Hot water is passed under pressure through the coffee powder pack to obtain espresso coffee.

[0004] Coffee powder is obtained by a coffee grinding machine. In known coffee grinding machines, coffee beans are ground by passing them through grinding elements. Flat, conical or mixed grinding elements are known. Typically, the grinding elements of a coffee grinding machine comprise a fixed element and an element that rotates relative to the fixed element. For example, in coffee grinding machines with flat burrs, one burr remains stationary, i.e., fixed, while the other burr is rotated by a motor. Some coffee grinding machines allow the distance between the burrs to be modified in order to vary the particle size of the coffee powder.

[0005] US Pat. No. 5,649,999 describes a machine with a flat grinder for milling grain. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 4,037,798A Summary of the Invention [Problem to be solved by the invention]

[0007] According to the Applicant, the main objective of manufacturers of coffee grinding machines (both with flat burrs and with conical burrs) is to obtain a particle size that is repeatable and constant over time, characterized by a dominant curve that is as limited as possible, with the aim of obtaining a similar water exchange area for all powder particles and therefore a similar solute extraction response for the majority of granules.

[0008] The applicant believes that the alignment of the bars plays the most important role in achieving this goal. In fact, when the bars are aligned, the powder outlet openings have the same height around the entire circumference of the two bars. On the other hand, when the bars are not aligned, the height of the outlet openings differs, resulting in different powder particle sizes.

[0009] Additionally, applicants have considered that the overall stability of the kinematic mechanical system during operation, including during the steps required to adjust particle size, is also very important.

[0010] The applicant has observed that if the alignment of the bars is not optimal, some very fine particle types cannot be obtained, for example particle sizes suitable for brewing Turkish coffee will not be obtained. In any case, a non-optimal particle size can result in a lower quality beverage being obtained.

[0011] The applicant has realized that a machine with flat bars, due to its construction, requires very precise horizontal alignment: in fact, the cutting edges extend along a horizontal component and the grinding flow direction extends radially, in other words, it is desirable for the flat bars to be perfectly parallel to each other.

[0012] The applicant has noticed that the fixed upper millstone 18 of the grain mill described in Patent Document 1 is constrained to the cylindrical vessel 10 and has no degree of freedom, i.e., is in a rigidly fixed position relative to the cylindrical vessel 10. Instead, the rotatable lower millstone is elastically pivotable and its position is dynamically adjusted. This solution does not guarantee accurate alignment of the millstones.

[0013] According to the invention, the problem of accurate alignment of the flat bar in a coffee grinding machine is solved by a molded coupling between the grinder holder body and the fixed bar, which is preferably a coupling realized by a curved surface, for example a spherical or substantially spherical surface. [Means for solving the problem]

[0014] According to a first aspect, the present invention provides a coffee grinding machine comprising a flat bar, The first bar and a motor configured to rotate the first bar about an axis of rotation; a second bar configured to cooperate with the first bar to grind the coffee beans, the second bar including a second surface; a grinder holder body lockable to the second bar, the grinder holder body including a first surface at least partially facing the second surface and cooperating with the second surface; wherein one of the first surface and the second surface is a spherical surface; 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; A coffee grinding machine is provided in which the first surface and the second surface cooperate with each other to properly orient the first burr relative to the second burr before locking the second burr to the grinder holder body.

[0015] According to an embodiment, the second surface extends substantially along the outer edge of the second bar, i.e. in the vicinity of the outer edge of the first bar.

[0016] According to an embodiment, the first surface is spherical and the second surface is spherical, such that there is surface contact between the first surface and the second surface.

[0017] According to an embodiment, the second surface is spherical and the first surface is conical, or the second surface is conical and the first surface is spherical, such that contact along a line is provided between the first and second surfaces.

[0018] According to an embodiment, the first surface is a first serrated surface and the second surface is a spherical surface such that contact is provided along one or more lines between the first surface and the second surface.

[0019] According to an embodiment, the first surface comprises a deformable element and the second surface is spherical, such that a resilient contact is provided between the grinder holder body and the second bar.

[0020] According to an embodiment, the grinder holder body can be removably coupled to the second bar by a connecting member, for example a fastening screw.

[0021] According to an embodiment, the coffee grinding machine also comprises an element allowing partial support of the connecting member.

[0022] According to an embodiment, the element comprises a conical spring washer or a conical Schnorr® type safety washer.

[0023] According to another aspect, there is provided a method of orienting burrs relative to one another in a flat burr coffee grinding machine, the method comprising: a first rotatable bar; a second bar configured to cooperate with the first bar to grind the coffee beans, the second bar including a second surface; a grinder holder body removably connectable to the second burr, the grinder holder body having a first surface at least partially facing the second surface and cooperating with the second surface; wherein one of the first surface and the second surface is spherical, and the other of the first surface and the second surface is spherical, or comprises a conical surface, or comprises a serrated surface, or comprises a deformable element. - preparing a coffee grinding machine; - orienting the second bar relative to the first bar; - locking the second burr to the grinder holder body; wherein the orienting step includes moving the second burr and the grinder holder body relative to one another along the first surface and the second surface, and the releasably coupling thereof is performed after the orienting step.

[0024] According to an embodiment, the second surface extends substantially along the outer edge of the second bar, i.e. in the vicinity of the outer edge of the first bar.

[0025] According to an embodiment, the orienting step includes orienting the second bar with respect to the first bar such that the first bar is parallel to the second bar.

[0026] According to an embodiment, the opposing curved surfaces include spherical surfaces.

[0027] The first bar can include a first plane at its outer rim, and the second bar can include a second plane at its outer rim, and the orienting step includes bringing the second bar closer to the first bar such that the first plane and the second plane are aligned with each other.

[0028] According to an embodiment, after the first plane and the second plane are arranged parallel to each other, the second bar is releasably locked to the grinder holder body.

[0029] According to an embodiment, the second bar is releasably locked to the grinder holder body by a screw and optionally a conical spring washer or a Schnorr® type safety washer.

[0030] Next, a detailed description of the present invention is provided as merely a non-limiting example for reading with reference to the accompanying drawings.

Brief Description of the Drawings

[0031] [Figure 1.1] It is a schematic view of a coffee grinder machine provided with a flat bar according to an embodiment of the present invention. [Figure 1.2] It is a longitudinal sectional view of the machine shown in FIG. 1.1. [Figure 2] It is an enlarged schematic axonometric projection view of the bar of the machine shown in FIG. 1.2. [Figure 3] It is an enlarged longitudinal sectional view of the bar of the machine shown in FIG. 1.2. [Figure 4] It is a detailed exploded view of the bar assembly shown in FIG. 3. [Figure 5] It is an exploded sectional view of the bar assembly. [Figure 6] FIG. 1 is an exploded cross-sectional view of a bar assembly. [Figure 7.1] FIG. 10 is an enlarged view of the two parts of the double spherical contact coupling between the fixed bar and the grinder holder. [Figure 7.2] FIG. 10 is an enlarged view of the two parts of the double spherical contact coupling between the fixed bar and the grinder holder. [Figure 8.1] An enlarged view of the two parts of the coupling by spherical / conical coupling between the fixed bar and the grinder holder. [Figure 8.2] An enlarged view of the two parts of the coupling by spherical / conical coupling between the fixed bar and the grinder holder. [Figure 9.1] FIG. 10 is an enlarged view of two parts of the serrated and spherical coupling between the fixed bar and the grinder holder. [Figure 9.2] FIG. 10 is an enlarged view of two parts of the serrated and spherical coupling between the fixed bar and the grinder holder. [Figure 10.1] FIG. 10 shows an enlarged view of two parts of the coupling by a spherical surface and a deformable element between the fixed bar and the grinder holder. [Figure 10.2] FIG. 10 shows an enlarged view of two parts of the coupling by a spherical surface and a deformable element between the fixed bar and the grinder holder. DETAILED DESCRIPTION OF THE INVENTION

[0032] Figures 1.1 and 1.2 show a coffee grinding machine according to an example of embodiment of the invention. Obviously, the coffee grinding machine according to the invention may take forms quite different from those shown without departing from the scope of protection of the invention.

[0033] The machine 10 comprises a machine body 12 containing the main components, including a grinding chamber with a burr assembly 30. Typically, the machine 10 comprises a hopper 14 at its top, which is configured to contain coffee beans to be ground and to allow the coffee beans to reach the grinding chamber and the burr assembly 30.

[0034] The machine 10 may also be equipped with a device 15 for adjusting the fineness of the powder to be ground, for example a knurled ring nut as shown in Figure 1.1.

[0035] The machine 10 also includes an outlet duct 16 for directing the ground coffee into a filter 18, which is supported by a filter holder 20. Advantageously, a support 22 may be provided for supporting the filter holder 20 while the filter 18 is being filled with ground coffee powder. The support 22 is adjustable in height. Also shown in Figure 1.1 are a push button 26 for operating the coffee grinding machine and an LED (or display) for indicating the status of the machine 10.

[0036] Figure 1.2 shows a longitudinal section of the machine according to Figure 1.1. In addition to the components already mentioned, the bar assembly 30 and the electric motor 24 for rotating one bar relative to the other are shown.

[0037] The bar assembly 30 is shown in greater detail in various Figures 2-6.

[0038] Also shown in the various Figures 2-6 is a grinding chamber comprising a bar assembly 30 including a lower bar 2 and an upper bar 3.

[0039] According to the embodiment shown, the lower bar 2 is a movable bar. It is kinematically connected to the motor shaft in any known manner. This connection can be realized, for example, by a grinder holder flange disc 1, which rotatably supports the lower bar 2.

[0040] Advantageously, the flange disc 1 may be provided with a suitable radial profile 2a adapted to eject the ground coffee from the bars 2, 3 of the grinding chamber.

[0041] In this specification and the associated drawings, it is clear that the arrangement of the axes AA of the bars 2, 3 is vertical. However, the invention is also applicable to coffee grinding machines in which the bar axes are horizontal or at a different inclination to the vertical. In fact, as shown in Figure 1.2, the axes AA of the bars are inclined to the vertical. The bars can also be arranged differently, such as with a movable bar at the top or with two movable bars.

[0042] The upper bar 3 is aligned on the same axis AA. For the reasons mentioned above, the upper bar 3 must be perfectly parallel to the lower bar 2. The upper bar 3 is fixed to a threaded grinder holder element 4 with a specially defined pitch and a ring nut 15, which determines the grinding adjustment via the relative axial spacing of the bars 2 and 3.

[0043] For the purposes of this specification and the claims, the expression "plane of the (flat) bar" or similar expressions means the plane defined when the bar is placed on a horizontal surface. The plane of the bar also coincides with the plane in which the outer periphery of the outer rim of the bar lies near the outlet.

[0044] For purposes of this specification and the claims, the expression "aligning the bars" means properly orienting two cooperating flat bars relative to each other so that the plane of one bar is parallel to the plane of the other bar.

[0045] For purposes of this specification and the claims, the term "spherical surface" refers to a surface corresponding to a portion of a sphere. This term refers to both concave and convex spherical portions.

[0046] For purposes of this specification and the claims, the expression "conical surface" denotes a surface corresponding to a portion of a frustum of a cone.

[0047] Axial grinding adjustment is performed indirectly: during adjustment, the threaded grinder holder body 4 and the upper bar 3 fixed to it are therefore not rotated by appropriate radial positioning elements 11, but are instead moved vertically by rotation of the ring nut 15.

[0048] According to the embodiment, the play caused by the engagement between the thread of the ring nut 15 and the grinder holder element 4 is taken up by the axial spring 6, whose pushing action acts in the direction of the grinding thrust.

[0049] In known coffee grinding machines, the flat bar is usually connected to the grinder holder element by a plane perpendicular to its axis.

[0050] The present invention provides a configuration in which the fixed upper bar 3 "floats" relative to the grinder holder body 4 before the fixed upper bar 3 is firmly clamped to the grinder holder body 4. This function is ensured, according to one embodiment, by a special spherical machining, namely, a spherical surface 3a extending along the outer edge of the fixed bar 3. This spherical surface 3a is configured to mate with a spherical seat 4a formed on the grinder holder body 4.

[0051] The alignment (i.e. parallel placement) of the bars 2, 3 is carried out by bringing the two bars into contact with each other via the adjusting ring nut 15. In other words, the fixed upper bar 3 is moved closer to the lower bar 2 until the planes 2b and 3b of the outer rims of the undercut areas of the teeth are perfectly aligned with each other. The floating coupling (before clamping) makes it possible to compensate for any alignment errors caused by the various components.

[0052] In this position, which is essentially a completely parallel arrangement, the upper bar 3 is rigidly fixed, for example by means of a series of screws 8 arranged in the area of the spherical coupling rim 3a.

[0053] According to an embodiment, the clamping is done gradually, and it is recommended that the screws 8 are cross-tightened.

[0054] To compensate for a deviation of a few microns under the head of the screw 8, an element may be used that can partially support the screw, such as a conical spring washer 9. For example, a Schnorr® type safety washer can be used.

[0055] Once clamping is complete, the upper bar 3 is positioned perfectly parallel to the lower bar 2, and this state is maintained under all conditions of use and at all adjustment settings of the coffee grinding machine.

[0056] As will become apparent, for automatic alignment (automatic parallel positioning) of the bars by the spherical coupling, both the upper bar 3 and the grinder holder body 4 are provided with two seats 3a and 4a, both of which are spherical. This type of coupling is also shown in enlarged views in Figures 7.1 and 7.2. The grinder holder 4 has a spherical surface 4a and the upper bar has a corresponding spherical surface 3a.

[0057] However, variations of this embodiment are possible, and these variations are also shown in Figures 8.1, 8.2, 9.1, 9.2, and 10.1, 10.2.

[0058] According to a first variant (FIGS. 8.1 and 8.2), the upper bar 3 comprises a spherical contact surface 3a, while the surface 4a directly facing the spherical contact surface 3a comprises a conical surface.

[0059] Alternatively, according to a variant, the upper bar 3 comprises a conical surface 3a, while the surface 4a directly facing the conical surface 3a comprises a spherical contact surface.

[0060] According to another variant (Figs. 9.1 and 9.2), the upper bar 3 comprises a spherical contact surface 3a, while the surface 4a directly facing the spherical contact surface 3a comprises a serrated surface with two or more grooves. In this case, contact between the spherical contact surface 3a and the surface 4a occurs along one of the circumferences corresponding to the ridges of the grooves.

[0061] According to another variant (substantially opposite to that shown in Figures 9.1 and 9.2), the upper bar 3 comprises a serrated surface 3a with two or more grooves, while the surface 4a directly facing the serrated surface comprises a spherical surface. In this case, contact between the spherical contact surface 3a and the surface 4a occurs along one of the circumferences corresponding to the ridges of the grooves.

[0062] According to another variant (Figs. 10.1 and 10.2), the upper bar 3 comprises a spherical contact surface 3a, while the surface 4a directly facing the spherical contact surface 3a comprises a preferably elastic, deformable body. For example, this can be an elastomer ring partially inserted into a corresponding seat. The elastomer ring can be designed to keep the bar in place after applying an appropriate pretensioning force by means of a clamping screw.

[0063] Obviously, any reference to relative positions, e.g. "upper bar" and "lower bar", etc., does not limit the scope of the present invention, in other words the upper bar may be rotatable and the lower bar fixed, while remaining within the scope of protection of the present invention.

Claims

1. A coffee grinding machine (10) equipped with a flat bar, The first bar (2), A motor (24) configured to rotate the first bar (2) around a rotation axis (A-A), A second bar (3) configured to grind coffee beans in cooperation with the first bar (2), the second bar (3) including a second surface (3a), A grinder holder body (4) that can be locked onto the second bar (3), the grinder holder body (4) having a first surface (4a) that is at least partially facing the second surface (3a) and cooperating with the second surface (3a), Equipped with, Either the first surface (4a) or the second surface (3a) is spherical, The other of the first surface (4a) and the second surface (3a) is spherical, or includes a conical surface, or includes a serrated surface, or includes a deformable element. A coffee grinding machine (10) wherein the first surface (4a) and the second surface (3a) cooperate with each other so that the first bar (2) is properly oriented relative to the second bar (3) before the second bar (3) is locked into 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 bar (3).

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

4. Coffee grinding machine (10) according to claim 1 or 2, wherein the second surface (3a) is spherical and the first surface is conical (4a), or the second surface (3a) is conical and the first surface is spherical (4a), such that line-aligned contact 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 spherical, 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 includes a deformable element and the second surface is spherical, so as to provide elastic contact between the grinder holder body (4) and the second bar (3).

7. The coffee grinding machine (10) according to claim 1, wherein the grinder holder body (4) can be detachably connected to the second bar (3) by a connecting member, for example, a tightening screw (8).

8. The coffee grinding machine (10) according to claim 7, further comprising an element (9) that enables partial support of the connecting member.

9. The coffee grinding machine (10) according to claim 8, wherein the element (9) includes a conical spring washer (9) or a conical Schnorr® type safety washer.

10. A method for aligning the bars (2, 3) relative to each other in a flat bar coffee grinding machine, A rotatable first bar (2), A second bar (3) configured to grind coffee beans in cooperation with the first bar (2), the second bar (3) including a second surface (3a), A grinder holder body (4) that can be detachably coupled to the second bar (3), the grinder holder body (4) having a first surface (4a) that is at least partially facing the second surface (3a) and cooperating with the second surface (3a), The device comprises, wherein either the first surface (4a) or the second surface (3a) is spherical, and the other of the first surface (4a) or the second surface (3a) is spherical, or includes a conical surface, or includes a serrated surface, or includes a deformable element. - Steps to prepare the coffee grinding machine (10), - The step of oriented the second bar (3) relative to the first bar (2), - The step of locking the second bar (3) to the grinder holder body (4), Includes, The orientation step includes moving the second bar (3) and the grinder holder body (4) relative to each other along the first surface and the second surface, and the step of removably coupling them is performed after the orientation step.

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

12. The method according to claim 10 or 11, wherein the orientation step includes oriented the second bar (3) with respect to the first bar (2) such that the first bar (2) is parallel to the second bar (3).

13. The method according to claim 10, wherein the opposing curved surfaces include a sphere.

14. The method according to claim 10, wherein the first bar (2) has a first plane (2b) on its outer rim, and the second bar (3) has a second plane (3b) on its outer rim, and the orientation step includes bringing the second bar (3) closer to the first bar (2) until the first plane (2b) and the second plane (3b) are aligned with each other.

15. The method according to claim 10, wherein the first plane (2a) and the second plane (3a) are arranged parallel to each other, and the second bar (3) is releasably locked to the grinder holder body (4).

16. The method according to claim 10, wherein the second bar (3) is releasably locked to the grinder holder body (4) by a screw and optionally a conical spring washer (9) or a Schnorr® type safety washer.

Images