Grinding mill, grinding disc of grinding mill and coffee machine having such grinding mill

Abstract

A grinding machine (1) for grinding coffee beans comprises: a first grinding disc holder (M1) with a first grinding disc (2), a second grinding disc holder (M2) with a second grinding disc (3), and a drive unit (4), at least one of the two grinding discs (2, 3) being rotatably operated by the drive unit. At least the grinding disc (3) of the two grinding discs (2, 3) being rotatably operated by the drive unit (4) is coupled to the drive unit (4) directly or indirectly by a central form-locking connection, wherein the central form-locking connection is constructed as a continuous shaft-hub-connection which subsequently transmits a torque directly or indirectly from the drive unit (4) to the grinding discs (2, 3). A grinding disc (2, 3) and a coffee machine are provided.

Description

Technical Field

[0001] The invention relates to a grinding machine for grinding coffee beans, as well as a grinding disc and a coffee machine, in particular a fully automatic coffee machine, having such a grinding machine. Background Art

[0002] From the prior art, coffee grinders for use in coffee machines are basically known in two proven designs. One is a disc grinder and the other is a conical grinder. Both types of grinders have in common that they consist of two grinding discs, one of which is fixed and the other driven. The coffee beans to be ground are introduced into the grinding gap by the rotational movement of the grinding discs and are ground increasingly finely by the narrowing grinding gap width. The minimum distance between the two grinding discs is decisive for the resulting degree of grinding of the coffee powder.

[0003] Typically, grinding discs of disc mills are fixed to the corresponding holders by means of screw holes. On the one hand, these holes reduce the cutting efficiency of the grinding discs. On the other hand, coffee powder can accumulate in these areas and therefore cannot be completely discharged from the mill.

[0004] Another possibility for a receptacle is described in EP 1 493 368 B1. The grinding disc is screwed into a corresponding holder by means of a bayonet connection. For this purpose, an elongated interrupted bulge is provided at the circumference of the grinding disc, which is introduced into the holder gap by means of a plug-in rotational movement. Since the grinding machine is always operated only in the direction of rotation, the disc and the holder are locked in rotation and the disc is also blocked in terms of axial freedom. Summary of the invention

[0005] The object of the present invention is therefore to further develop a grinding mill of the generic type in a functionally advantageous manner.

[0006] The invention achieves this object by means of a grinding machine, a grinding disc and a coffee machine.

[0007] The grinding machine according to the invention for grinding coffee beans comprises a first grinding disc holder with a first grinding disc, a second grinding disc holder with a second grinding disc, and a drive unit, by which at least one of the two grinding discs is rotatably moved. At least one of the two grinding discs rotatably moved by the drive unit is coupled to the drive unit directly or indirectly by a central form fit, wherein the central form fit is designed as a continuous shaft-hub connection which subsequently transmits a torque directly or indirectly from the drive unit to the grinding discs.

[0008] In order to transmit the drive torque from the drive unit to the grinding disk, it is advantageous to achieve a form fit between the grinding disk and the carrier which transmits high forces and at the same time does not cause disruptive openings in which coffee powder could accumulate.

[0009] The grinding machine according to the present invention is used for grinding coffee beans. The grinding machine can be used as a stand-alone device or integrated in a coffee machine, for example in a fully automatic coffee machine.

[0010] The grinding disc according to the invention for the grinding machine proposed above has a through opening with a central inner contour. This central inner contour is very advantageous for simple and rapid assembly or conversion.

[0011] In one embodiment, a second grinding disc rotatably operated by a drive unit has a through-hole with a central inner contour, which is in form-locking engagement with a central contour of a support of the second grinding disc support, wherein the support is connected to a drive shaft of the drive unit.

[0012] The coffee machine according to the invention, in particular a fully automatic coffee machine, comprises the grinding machine described above.

[0013] Particular advantages result from the positive fit at the inner through-region of the grinding disc, which is usually designed as a simple hole and where no finely ground coffee powder is present at this location during the grinding process. The through-structure is designed as a positive-fitting contour. Advantageously particularly large drive and holding torques can then be transmitted without disruptive geometries occurring at the outer diameter of the grinding disc.

[0014] A further particular advantage is that, in contrast to the prior art, there are no screw-on holes with screws, which does not adversely affect the cutting efficiency of the grinding discs and thus does not allow coffee powder to accumulate in these areas. The coffee powder can therefore be completely discharged.

[0015] In a further embodiment, the support of the second grinding disk support has an annular section which is arranged around the central contour, thereby resulting in a simple bearing surface for the second grinding disk.

[0016] It is also advantageous if the support of the second grinding disk support has a free space which is defined by the contour of the annular segment and the center, thereby making it possible to easily provide additional accommodation for a segment of the grinding disk.

[0017] Another embodiment provides that the first grinding disc and the second grinding disc each have a through-hole with a central inner contour, wherein the first grinding disc with its central inner contour is in positive engagement with a central contour projection of the holder of the first grinding disc holder. This results in the advantage that only one grinding disc design is required for the grinding machine, wherein the two grinding discs can be identical.

[0018] If the profile projection of the support of the first grinding disk support has a central opening, it can advantageously be achieved that this central opening allows coffee beans to pass from the charging hopper into the grinding chamber between the grinding disks.

[0019] In another embodiment, it is provided that the first grinding disc and the second grinding disc each have radially projecting projections, which are formed in a regularly distributed manner on the outer circumference of the first grinding disc and the second grinding disc. These projections are also called snap-in projections and are advantageously used to fix the grinding disc axially in the corresponding grinding disc holder. Since the torque for the corresponding grinding disc is transmitted by the shape lock between the contour of the holder and the internal contour of the internal penetration structure of the corresponding grinding disc, the projections can be implemented very finely because they do not transmit torque. In the case of the first grinding disc, when the first grinding disc is stationary, the assigned torque is a holding torque. In the case of the second grinding disc operated by the drive unit, the assigned torque is a driving torque.

[0020] Based on this structural embodiment, it is also advantageously possible to design the lower and upper grinding disk as a common part.

[0021] In yet another embodiment, the first grinding disc is inserted into a holder of the first grinding disc holder and is guided axially in the holder and fixed axially by means of a projection. In a further embodiment, this first grinding disc, or also referred to as the upper grinding disc, can be permanently clipped into the plastic holder, including a compression spring for force control. Furthermore, the plastic holder can also be inserted and locked or clipped into the holder. This allows for an advantageously simple assembly.

[0022] In one embodiment, the first grinding disk can advantageously be inserted into the holder of the first grinding disk holder in such a way that a projection is respectively guided in an axially displaceable manner in a recess and is received in an axially fixed manner.

[0023] This is also advantageous because an axial degree of freedom for the first grinding disk is created in this way for force control.

[0024] In another embodiment, web-like projections are arranged in a regularly distributed manner on the outer circumference of the annular section of the support of the second grinding disc support, extending from the annular section of the support of the second grinding disc support, wherein the web-like projections each have a shaped recess which engages with a corresponding protrusion of the second grinding disc.

[0025] In this way, the projection can be embedded in the recess in the lower support, that is to say the second grinding disc support, in an ideal manner behind the thrower geometry (which is formed here by the web-like projection). The projection can then also be used as a guide when inserting the grinding disc.

[0026] The mill can be designed as a disk mill, a roller mill or a cone mill. The adjustment device thus has an advantageously large range of use.

[0027] In another embodiment, the inner contour of the center of the grinding disc, the contour projection of the support of the first grinding disc holder and the contour of the center of the support of the second grinding disc holder are configured as polygons, preferably as hexagons, triangles, quadrangles, ovals, ellipses, etc. wherein the inner contour of the center of the first grinding disc and the contour projection of the support of the first grinding disc holder correspond to each other, and wherein the inner contour of the center of the second grinding disc and the contour of the center of the support of the second grinding disc holder correspond to each other.

[0028] In the event that the operator no longer wants to remove the second grinding disc from the mill, the contour, for example as a hexagon, can have an interference fit in the driven second grinding disc and its holder when the second grinding disc is inserted into the plastic holder. If it is desired to remove the second grinding disc for maintenance reasons, the form fit (for example the hexagon) is designed as a clearance fit. Since the grinding discs are pressed against each other during the grinding process, no additional axial fixing of the second grinding disc is required. The second grinding disc is thus advantageously easily inserted into the holder, which represents a very easy-to-assemble and easy-to-maintain solution.

[0029] When only one type of grinding disc is used in a grinding machine with two grinding discs, the grinding disc can have radially projecting projections which are formed in a regularly distributed manner on the outer circumference of the grinding disc. These projections then serve, on the one hand, only for guiding the second grinding disc when it is inserted into the holder of the second grinding disc holder and, on the other hand, for axially guiding and axially stopping the first grinding disc in the holder of the first grinding disc holder.

[0030] Further advantageous embodiments result from the remaining preferred exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is described in more detail below based on embodiments with reference to the accompanying drawings. The accompanying drawings are only used to explain the present invention in more detail and are not restrictive of the present invention. The individual described features themselves can also be transferred to other design variants within the scope of common professional knowledge. Among them:

[0032] Figure 1 A schematic front view is shown in section of the principle of a grinding machine according to the invention for grinding coffee beans;

[0033] Figure 2 Shown according to Figure 1 A schematic exploded view of an embodiment of a mill according to the present invention;

[0034] Figure 3-4 The invention shows a grinding disc according to Figure 2 A schematic diagram of a drive unit of a grinding mill according to the present invention;

[0035] Figure 5-6 The grinding disc holder is shown together with the Figure 2 A schematic exploded view of a grinding disc of a grinding mill according to the present invention;

[0036] Figure 7-9 Shown according to Figure 2 A schematic diagram of a grinding disc of a grinding mill according to the present invention; and

[0037] Figure 10-11 Shown according to Figure 7-9 A schematic cross-sectional view of a grinding disc; and

[0038] Figure 12-14 Shown according to Figure 7-9 Schematic sectional illustration of a grinding disk in different stroke positions. DETAILED DESCRIPTION

[0039] exist Figure 1 Detailed Description of the Invention A schematic front view is shown in section of the principle of a grinding machine 1 according to the invention for grinding coffee beans 5 . Figure 2 Shown according to Figure 1 Schematic exploded view of an exemplary embodiment of a grinding mill 1 according to the invention.

[0040] The mill 1 has a mill axis 1a, a first grinding disc holder M1 with a first grinding disc 2, a second grinding disc holder M2 with a second grinding disc 3, and a drive unit 4. The grinding discs 2, 3 are designed here as so-called grinding discs. The first grinding disc 2 is mounted in a rotationally fixed manner in the first grinding disc holder M1. In this respect, the first grinding disc 2 is stationary during operation of the mill 1.

[0041] The first grinding disc 2 has a cylindrical envelope geometry and a central opening 5. The first grinding disc 2 can also be designed differently from a grinding cone, for example. The opening 5 here engages through a charging hopper 6. The coffee beans 7 to be ground are supplied to the grinding machine 1 via the charging hopper 6 and the opening 5. The grinding machine 1 can also be provided for grinding other treats or foods, but it is preferably provided for grinding coffee beans 7. The charging hopper 6 is advantageously designed in such a way that undesired bridging of the coffee beans 7 in the charging hopper 6 is prevented.

[0042] Each grinding disc 2, 3 has a rear side 8, 9 and a grinding side 10, 11. The rear side 8 of the first grinding disc 2 faces the charging hopper 6. The rear side 9 of the second grinding disc 3 is coupled to the drive unit 4. This will be explained in more detail below.

[0043] The grinding sides 10 , 11 are each provided with a recess 12 , 13 , which is concave or conical in this case, and with at least one grinding tool 14 , 15 .

[0044] The grinding discs 2, 3 are arranged with their grinding sides 10, 11 facing each other. The second grinding disc 3 of the second grinding disc carrier M2 is arranged coaxially with the mill axis 1a and coaxially with the first grinding disc 2 and below the first grinding disc 2. The term "below" refers to Figure 1 The second grinding disc 3 rotates during operation of the grinding mill 1. This is explained in more detail below.

[0045] The conical depression 12 of the first grinding disc 2 and the conical depression 13 of the second grinding disc 3 thus form a biconical grinding chamber 16, which opens at its periphery into the grinding gap 17. A collecting device (not shown here) can be connected to the grinding gap 17, which collects the coffee beans, preferably coffee powder, emerging from the grinding gap 17 and supplies it to the extraction process.

[0046] The second grinding disc 3 also has a cylindrical envelope geometry. The second grinding disc 3 can also be designed differently from a grinding cone, for example. The second grinding disc 3 can be rotated about the mill axis 1a relative to the first grinding disc 2. The second grinding disc 3 is coupled to the drive unit 4 in such a way that, during operation of the mill 1, the second grinding disc 3 is set in rotation, while the first grinding disc 2 is stationary.

[0047] This is advantageous but not mandatory. Alternatively, the first grinding disc 2 can also rotate while the second grinding disc 3 is stationary. It is also possible that the two grinding discs 2, 3 can rotate, for example, in counter-rotating motions and / or at different speeds, so that a relative movement always occurs between the two grinding discs 2, 3.

[0048] The grinding machine 1 also has at least one force generating device 18. In this case, the force generating device 18 acts on the first grinding disc 2. As a result, a corresponding force F acts continuously on the coffee beans between the first grinding disc 2 and the second grinding disc 3. This is advantageous but not mandatory. The force generating device 18 can also act on the rotatable second grinding disc 3 or on both grinding discs 2, 3.

[0049] The force generating device 18 comprises two compression springs 18a which can be preloaded by corresponding devices (not shown here and not discussed further), such as servomotors, with a variable preload travel X, so that the corresponding force F acting on the first grinding disc 2 and thus on the coffee beans is variable or can be set in terms of its value. The compression springs 18a exert an axial force which can be adjusted or varied in this way perpendicularly to the plane E of the grinding gap 17 on the first and / or second grinding disc 2, 3.

[0050] Furthermore, the force acting on the coffee beans by the grinding machine 1 can be advantageously set by the force generating device 18 as a function of the coffee beans 7 to be ground and the corresponding desired degree of grinding. For this purpose, data sets relating to the corresponding degree of grinding, the type of beans and the force to be generated by the force generating device 18 are preferably stored in a data memory of a control and / or analysis unit 19 for controlling the coffee machine and in particular the grinding machine 1. The aforementioned control and / or analysis unit 19 can be assigned to the grinding machine 1 or can be part of a coffee machine, for example a fully automatic coffee machine.

[0051] The second grinding disc 3 is driven by a drive motor 20 of the drive unit 4 via a drive shaft 21, which is Figure 1 It is only briefly shown in the figure.

[0052] Alternatively, a shaftless direct drive is also possible, in which one of the grinding disks 2 , 3 is the rotor of the drive motor 10 , or an indirect drive is also possible, in which the drive motor 10 acts on one of the grinding disks 2 , 8 via a gear mechanism.

[0053] As in Figure 2 As shown in FIG. 1 , the first grinding disk support M1 comprises the first grinding disk 2, the charging hopper 6 and the support 24 ′. The first grinding disk support M1 is also referred to as the upper grinding disk support M1 .

[0054] The first grinding disc holder M1 is assembled with the first grinding disc 2 in the grinding housing 23 together with the second grinding disc 3 as in Figure 1 The arrangement is schematically shown in FIG.

[0055] The mill housing 25 is arranged coaxially with respect to the mill axis 1 a and has, in a bottom section (not shown), a throwing section 23 a which is open radially outwards. The mill housing 25 is not described in any further detail.

[0056] In addition, Figure 2 1 and 2 , a grinding degree indicator (not shown) is described, which interacts with an adjustment device (also not shown) of the force generating device 18. The grinding degree indicator is not described in any further detail here.

[0057] The second grinding disk carrier M2 is also referred to as lower grinding disk carrier M2 and comprises the second grinding disk 3 and the carrier 24 .

[0058] The second grinding disc 3 is placed on the support 24 and connected to it in a rotationally fixed manner. For this purpose, the contour 25 of the support 24 is in engagement with the inner contour 29 of the second grinding disc 3. This will be explained in more detail below.

[0059] The bracket 24 is connected to the drive shaft 21, which is arranged in the inner cavity of the housing of the transmission mechanism 22 of the drive unit 4. This is not shown, but it can be easily imagined. The drive motor 20 with a drive motor axis 20a is fastened to the housing of the transmission mechanism 22 by a tightening flange 22a in the present embodiment.

[0060] The mill housing 23 is fastened by fastening elements, such as screws, to a flange 22b of the housing of the transmission 22, which flange is facing upwards toward the milling disc holders M2, M1. The bottom section of the mill housing 23 surrounds the second milling disc 3, wherein the first milling disc 2 is then arranged in the upper section of the mill housing 23 in the assembled state.

[0061] Figure 3Shown according to Figure 2 Schematic perspective view of the drive unit 4 of the grinding machine 1 according to the invention with the second grinding disc 3 which has not yet been placed. Figure 4 , a schematic top view of the drive unit 4 is shown in the direction of the mill axis 1 a .

[0062] The drive unit 4 has, for example, a worm gear between a drive shaft 21 and a drive motor 20. The drive shaft 21 is connected at its upper end to a support 24 which rotates with the drive shaft about the mill axis 1a. The support 24 can also be designed integrally with the drive shaft 21.

[0063] The support 24 is provided with the follower and thrower geometry of the mill 1 on its upper side facing the mill housing 23. The support 24 comprises a contour 25, an annular section 26 and a web-like projection 27.

[0064] The contour 25 is designed here as a central outer contour in the form of a hexagon with a contour surface 25 a lying outward around the center of the support 14 through which the mill axis 1 a runs.

[0065] The annular section 26 is arranged coaxially to the contour 25 and the mill axis 1 a and surrounds the contour 25 , wherein an annular free space 26 a is defined between the contour 25 and the annular section 26 .

[0066] On the outer circumference of the annular section 26 , web-like projections 27 (here three projections 27 ) are arranged in a regularly distributed manner and project from the annular section 26 of the carrier 24 .

[0067] In the transition region between the projection 27 and the outer diameter of the annular section 26 , a corresponding upwardly open recess 28 is formed into the projection 27 .

[0068] Like the first grinding disk 2 , the second grinding disk 3 has a central opening which is referred to here as inner contour 29 and is formed with a contour surface 30 . The inner contour 29 of the second grinding disk 3 corresponds to the outer contour 25 of the carrier 24 of the drive unit 4 .

[0069] Protrusions 31 projecting radially at the edge facing the rear side 9 are formed at the outer circumference of the second grinding disc 3 in a regularly distributed manner. Here, there are three protrusions 31 .

[0070] In the assembled state, the second grinding disc 3 is placed on the support 24 in such a way that the inner contour 29 of the grinding disc 3 is in engagement with the outer contour 25 of the support 24, wherein the grinding disc axis 3a of the second grinding disc 3 runs coaxially with the support axis 24a of the support 24 and coaxially with the mill axis 1a. Furthermore, the back side 9 of the second grinding disc 3 rests on the annular section 26 of the support 24, wherein the annular projection 32 of the second grinding disc 3 (see Fig. 9 , Fig.10 ) extends into the free space 26a or is accommodated therein. An annular projection 32 extends from the back side 9 of the second grinding disc 3, such as can be Fig. 9 and Fig.10 Here, the projection 31 is received in the recess 28 of the projection 27 .

[0071] The contour 25 of the support 24 and the inner contour 29 of the second grinding disc 3 form an advantageous form fit between the second grinding disc 3 and the support 24 for transmitting the grinding disc torque, which transmits high forces and at the same time does not cause disruptive openings in which coffee powder could accumulate. This can be achieved in Figure 4 can be clearly identified in the top view.

[0072] A particularly elegant possibility is a positive fit at the inner through-region of the second grinding disc 3, which is usually designed as a simple through-hole or perforation and where no finely ground coffee powder is yet present at this location. However, the through-hole is designed as a positively locked inner contour 29, here for example as a hexagon. Of course, other geometric shapes such as, for example, a quadrangular, polygonal, oval, elliptical, etc. are also possible. In this way, particularly high torques can be transmitted without interfering geometries arising at the outer diameter of the second grinding disc 3.

[0073] The projection 31 formed on the circumference of the second grinding disc 3 is designed as a contour-integrated, so-called snap-in projection. Since the torque for the grinding disc, here the second grinding disc 3, is transmitted via the form fit between the contour 25 of the support 24 and the inner contour 29 of the inner penetration of the second grinding disc 3, the projection 31 can be designed very compactly since it does not transmit any torque.

[0074] The projection 31 in the lower grinding disc support M2 in the support 24 engages ideally behind the throw-away geometry, that is, in the recess 23 at the projection 27. Since both grinding discs 2, 3 are designed identically, the projection 31 for the second grinding disc 3 serves only for guidance. The function of the projection 31 in the first grinding disc 2 is explained below.

[0075] The contour 25 of the support 24 and the inner contour 29 of the second grinding disc 3 can form a fit. If the second grinding disc 3 should no longer be removed from the grinding mill 1 by an operator of the coffee machine to which the grinding mill 1 with the second grinding disc 3 is assigned, this fit can be designed as an interference fit.

[0076] If it is desired to remove the second grinding plate 3 for maintenance reasons, the positive fit of the contours 25, 29 (e.g. hexagonal) is designed as a clearance fit. Since the first grinding plate 2 and the second grinding plate 3 are pressed against each other during the grinding process, no further axial fixing of the lower, that is to say the second grinding plate 3, is necessary. The second grinding plate 3 is therefore merely inserted into the holder 24, which represents a very easy-to-assemble and easy-to-maintain solution.

[0077] Figure 5 Shown according to Figure 2 A schematic exploded view of the first grinding disc support M1 of the grinding machine 1 according to the invention together with the first grinding disc 2. Figure 6 It is shown in Figure 5 The views are shown rotated 180° about an axis perpendicular to the drawing. Figure 7 A schematic top view of the grinding sides 10, 11 of the grinding discs 2, 3 is shown. Figure 8 2 shows a schematic perspective view of the grinding sides 10, 11 of the grinding discs 2, 3; Fig. 9 A schematic perspective view of the rear sides 8 , 9 of the grinding disks 2 , 3 is shown. Fig.10 A schematic cross-sectional view of a grinding disc 2, 3 is shown, and Fig.11 Shows Fig.10 An enlarged cut-out portion XI with protrusions 31, 31'.

[0078] The upper or first grinding disk support M1 comprises the first grinding disk 2 with its grinding disk axis 2a, the compression spring 18a and the support 24 ′ with its support axis 24 ′ a.

[0079] In the present exemplary embodiment, the first grinding disc 2 is designed in the same manner as the second grinding disc 3, that is, the two grinding discs 2, 3 are identical. In order to distinguish between the second grinding disc holder M2 and the second grinding disc 3, the holder 24' of the first grinding disc holder M1, the inner contour 29' of the first grinding disc 2, the contour surface 30' and the projection 31' are provided with apostrophes.

[0080] Like the second grinding wheel 3 , the first grinding wheel 2 has a central opening which is indicated here as inner contour 29 ′ and is formed with a contour surface 30 ′.

[0081] The first grinding disk 2, which is spring-loaded by the compression spring 18a, is inserted into the support 24', guided in the support 24' and tensioned in a manner not shown. Here, the grinding disk axis 2a of the first grinding disk 2 and the support axis 24'a of the support 24' extend coaxially and, in the assembled state of the mill 1, extend coaxially with the mill axis 1a.

[0082] Here, the first grinding disc 2 together with the compression spring 18a for force control is permanently installed, for example clipped into a support insert 24c, for example a plastic support. The support insert 24c is installed in a manner not shown in more detail in a support base 24b of the support 24' and connected thereto, for example by a latching / clip connection. The support 24' is designed here as a multi-part component together with the support base 24b and the support insert 24c. However, the support 24' can also be designed as a one-piece structure with the support base 24b and the support insert 24c.

[0083] As in Figure 6 As shown in the figure, the support 24' has in its interior a protruding contour projection 33 with an outer contour surface 34. The contour projection 33 corresponds to the inner contour 24' of the first grinding disk 2. In contrast to the contour 25 of the second grinding disk support M2, the contour projection 33 of the first grinding disk support M1 is provided with a central opening 5a. This opening 5a extends or supplements the central opening 5 described above in order to enable the coffee beans 7 to pass from the charging funnel 6 into the grinding chamber 16 between the grinding disks 2, 3.

[0084] The contour-integrated projections 31′ (“snap-in projections”) advantageously formed on the circumference of the first grinding disc 2 ensure axial fixation of the first grinding disc 2 in the holder 24′ of the first grinding disc holder M1. The first grinding disc 2 is clipped into a holder insert 24c, for example a plastic holder, in such a way that the projections 31′ are each received in a displaceably guided manner in a recess 35 of the holder insert 24c. The recesses 35 extend parallel to the holder axis 24′a of the holder 24 and have at their lower ends a projection 36 which forms an axial stop for the respective stop surface 31′a of the projection 31′ guided in the associated recess 35. In this way, the first grinding disc 2 is fixed axially in the holder insert 24c of the holder 24.

[0085] The compression spring 18a is located between the back sides 8 of the first grinding disc 2 and is supported in a manner that is not shown but is easily conceivable on an associated support section of a support base 24b of a support 24'. The compression springs 18a are arranged symmetrically around the grinding disc axis 2a and around the mill axis 1a in order to achieve an optimally distributed force application. However, more than the three compression springs 18a shown can also be provided.

[0086] A helical spring is preferably used as the compression spring 18a for the present application. However, other spring designs or spring assemblies can also be used.

[0087] The first grinding disk 2 therefore has an axial degree of freedom in the direction of its grinding disk axis 2a, ie in the direction of the carrier axis 24'a and the mill axis 1a of the mill 1. This will be explained in greater detail below.

[0088] Since the tool torque, that is to say the holding torque, is transmitted by the form fit between the contour projection 33 of the support 24' and the inner contour 29' at the inner penetration of the first grinding disc 2, the engagement geometry (protrusions 31' and projections 36) can be designed very finely. Based on this structural embodiment, the lower and upper grinding discs 2, 3 can be designed as a common part.

[0089] exist Figure 7-9 , the shape of the inner contour 29, 29' with the contoured surfaces 30, 30' is shown as a hexagon with rounded corners. Other positive locking contours are of course possible, such as, for example, a quadrangular, polygonal, oval, elliptical, etc. Together with the contour 25 of the support 24 of the second grinding disc support M2, the inner contour 30 of the second grinding disc 3 is thus sealed in the installed state (see Figure 4 ), so that no coffee grounds can be stored in this area and simple cleaning is possible.

[0090] The inner contours 29, 29' are integrally formed into the grinding discs 2, 3 and also extend through the annular projections 32, 32', as can be seen in the example of FIG. Fig. 9 as clearly identified in .

[0091] The projections 31, 31' extend radially at the outer periphery of the grinding discs 2, 3 at the edge of the rear side 8, 9. The projections 31, 31' widen from the rear side 8, 9 to the stop surface 31a, 31'a in the axial direction with respect to the grinding disc axis 2a, 3a. Fig.11 Shown in an enlarged manner.

[0092] exist Fig.10It can be seen in FIG. 1 that the depressions 12 , 13 and the grinding tools 14 , 15 form a concave envelope on the grinding sides 10 , 11 .

[0093] Figure 12-14 Shown according to Figure 7-9 Schematic sectional illustration of first grinding disk 2 in different stroke positions relative to associated contour elevation 33 of first grinding disk carrier M1 .

[0094] exist Fig.12 In the embodiment shown in FIG. 2 , the grinding disc 2 is not pushed onto the contour projection 33. The first grinding disc 2 has an axial length L in the direction of the grinding disc axis 2a, that is, in the direction of the support axis 24′a. The length 33a of the contour projection 33 in the direction of the support axis 24′a is greater than the axial length L of the first grinding disc 2.

[0095] The surface of the annular projection 32 ′ serves as the stroke reference HR for further considerations.

[0096] exist Fig.13 In the embodiment shown, the first grinding disc 2 is displaced with its inner contour 29' in the direction of the axes 2a, 24'a onto the contour projection 33a to such an extent that a relative stroke H1 of the grinding disc 2 relative to the stroke reference HR is obtained. In the embodiment shown, this relative stroke H1 is slightly greater than the axial length of the annular projection 32'. The first grinding disc 2 thus has an axial degree of freedom in the direction of the axes 2a, 24'a.

[0097] This axial degree of freedom of first grinding wheel 2 with respect to contour elevation 33 also makes it possible to achieve a relative stroke H2 which is greater than the axial length L of first grinding wheel 2 . Fig.14 Here, the inner contour 29 ′ of the first grinding disc 2 is completely pushed onto the contour projection 33 a, and the contour projection 33 a protrudes through the inner contour 29 ′ from the region of the grinding tool 14 . This position can also be used to clean the depression 13 sunk into the grinding tool 14 .

[0098] The travel of the first grinding disk 2 relative to the contour elevation 33 can be limited, for example, by the first grinding disk 2 coming into contact with a travel reference HR against a stop (not shown) in the carrier 24 .

[0099] The torque for the grinding disc 2, 3, here the second grinding disc 3, is transmitted via the form fit between the contour 25 of the carrier 24 and the inner contours 29, 29' at the inner penetration of the grinding disc 2, 3. This form fit is the central form fit of a continuous shaft-hub connection, which is used to subsequently transmit the torque directly or indirectly from the drive to the grinding disc 2, 3. The central form fit is here between the contour 25 of the contour projection 33 of the carrier 24 and the inner contours 29, 29' of the grinding disc 2, 3.

[0100] The grinding discs 2, 3 are designed as one piece. The form fit is achieved directly by the geometrical features of the inner contour 29 of the grinding disc 3, for example as a hexagonal contour as already described above. Such a hexagonal contour has smooth walls and no grooves. Therefore, no additional parts and / or intermediate components such as, for example, matching springs are required. As a result, the locations where / in which coffee powder can accumulate are significantly minimized.

[0101] The invention is not restricted to the embodiments presented above, but can be modified within the scope of other embodiments.

[0102] For example, it is conceivable to insert the first grinding wheel 2 into the first grinding wheel holder 24 ′ without the spring 18 a .

[0103] List of reference numerals:

[0104] 1 Mill

[0105] 1a Mill axis

[0106] 2.3 Grinding disc

[0107] 2a, 3a Grinding disc axis

[0108] 4 Drivers

[0109] 5. Hole

[0110] 6 Loading funnel

[0111] 7. Coffee Beans

[0112] 8, 9 Dorsal

[0113] 10, 11 Grinding side

[0114] 12, 13 sinking part

[0115] 14, 15 Grinding tools

[0116] 16 Grinding chamber

[0117] 17 Grinding gap

[0118] 18 Force generating device

[0119] 18a Compression spring

[0120] 19 Control and / or analysis unit

[0121] 20 Drive motor

[0122] 20a Drive motor axis

[0123] 21 Drive shaft

[0124] 22 Transmission mechanism

[0125] 22a Motor flange

[0126] 22b Flange

[0127] 23 Milling shell

[0128] 23a Throwing section

[0129] 24, 24` bracket

[0130] 24a, 24`a Bracket axis

[0131] 24b Bracket base

[0132] 24c Bracket Insert

[0133] 25 Outline

[0134] 25a Contour surface

[0135] 26 Ring Segments

[0136] 26a Free Space

[0137] 27 Protrusion

[0138] 28 Forming Department

[0139] 29, 29` Internal profile

[0140] 30, 30` contour surface

[0141] 31, 31` Raised part

[0142] 31a, 31`a Stop surface

[0143] 32, 32` Annular protrusion

[0144] 33 Contour protrusion

[0145] 33a Length

[0146] 34 Contour surface

[0147] 35 grooves

[0148] 36 Protrusion

[0149] E-Plane

[0150] F-Force

[0151] H1, H2 itinerary

[0152] HR trip benchmark

[0153] L Axial length

[0154] M1, M2 grinding disc holder

[0155] X Preload travel.

Claims

1. A grinding machine (1) for grinding coffee beans (5), wherein: The mill (1) comprises: a first grinding disc support (M1) with a first grinding disc (2); a second grinding disc holder (M2) with a second grinding disc (3); and a drive unit (4), by which at least one of the two grinding discs (2, 3) is rotatably driven, 2, 20. The invention further comprises a step of: stepping into the driving mechanism of the present invention on a rotationally movable shaft, wherein the rotationally movable shaft is connected to the driving mechanism (4) via a central positive lock, wherein the central positive lock is configured as a continuous shaft-hub connection which subsequently transmits a torque from the driving mechanism (4) directly or indirectly to the grinding discs (2, 3), wherein at least one of the two grinding discs (2, 3) or both grinding discs (2, 3) has a through-hole with a central inner contour (29, 29′), and wherein the second grinding disc (3) of the two grinding discs (2, 3) which is rotatably driven by the driving mechanism (4) is coupled to the driving mechanism (4) directly or indirectly via a central positive lock. The through-opening with its central inner contour (29) is in form-locking engagement with the central contour (25) of the support (24) of the second grinding disc support (M2), wherein the torque for the second grinding disc (3) is transmitted via the form-locking of the contour (25) of the support (24) of the second grinding disc support (M2) with the inner contour (29) of the internal through-structure of the second grinding disc (3), this form-locking being the form-locking of the center of a continuous shaft-hub connection, wherein the continuous shaft-hub connection is used to subsequently transmit the torque from the drive directly or indirectly to the second grinding disc (3), wherein the support (24) is connected to the drive shaft (21) of the drive unit (4).

2. The grinding mill (1) according to claim 1, characterized in that The support (24) of the second grinding disk support (M2) has an annular section (26) which is arranged around the central contour (25).

3. The grinding mill (1) according to claim 2, characterized in that The support (24) of the second grinding disk support (M2) has a free space (26a) which is defined by the annular section (26) and the contour (25) of the center.

4. The mill (1) according to any one of claims 1 to 3, characterized in that The other grinding wheel (2) of the two grinding wheels (2, 3) is in positive engagement with a central inner contour (29') of the support (24') of the first grinding wheel support (M1).

5. The grinding mill (1) according to claim 4, characterized in that The contour projection (33) of the support (24') of the first grinding disk support (M1) has a central opening (5a).

6. The mill (1) according to any one of claims 1 to 3, characterized in that The two grinding discs (2, 3) respectively have radially extending protrusions (31, 31'), which are formed on the outer circumference of the two grinding discs (2, 3) in a regularly distributed manner.

7. The grinding mill (1) according to claim 6, characterized in that The other grinding wheel (2) of the two grinding wheels (2, 3) is inserted into a holder (24') of the first grinding wheel holder (M1) and is axially guided in the holder (24') and axially fixed by means of the projection (31').

8. The grinding mill (1) according to claim 7, characterized in that The other grinding disc (2) of the two grinding discs (2, 3) is inserted into the holder (24') of the first grinding disc holder (M1) in such a way that the projections (31') are guided axially displaceably and received axially fixedly in the grooves (35) of the holder (24') of the first grinding disc holder (M1).

9. The grinding mill (1) according to claim 4, characterized in that On the outer circumference of the annular section (26) of the support (24) of the second grinding disc support (M2), there are regularly distributed web-shaped projections (27), which extend from the annular section (26) of the support (24) of the second grinding disc support (M2), wherein the web-shaped projections (27) each have a formed recess (28) which engages with a corresponding protrusion (31) of the grinding disc (3) of the two grinding discs (2, 3) which is rotatably operated by the drive unit (4).

10. The mill (1) according to any one of claims 1 to 3, characterized in that The mill (1) is designed as a disk mill.

11. The mill (1) according to any one of claims 1 to 3, characterized in that The inner contours (29, 29') of the centers of the two grinding discs (2, 3), the contour protrusions (33) of the support (24') of the first grinding disc holder (M1), and the contour (25) of the center of the support (24') of the second grinding disc holder (M2) are constructed as polygonal ovals or ellipses, wherein the inner contour (29') of the center of the other grinding disc (2, 3) of the two grinding discs (2, 3) and the contour protrusions (33) of the support (24') of the first grinding disc holder (M1) correspond to each other, and wherein the inner contour (29) of the center of the grinding disc (3) of the two grinding discs (2, 3) that is rotatably operated by the drive unit (4) and the contour (25) of the center of the support (24) of the second grinding disc holder (M2) correspond to each other.

12. The grinding mill (1) according to claim 11, characterized in that The polygon is a hexagon, a triangular shape or a quadrangular shape.

13. The mill (1) according to any one of claims 1 to 3, characterized in that The two grinding discs (2, 3) are of identical design.

14. A grinding disc (2, 3) for a grinding mill (1) according to any one of the preceding claims, characterized in that The two grinding discs (2, 3) each have a perforation with a central inner contour (29, 29').

15. The grinding disc (2, 3) according to claim 14, characterized in that The two grinding discs (2, 3) respectively have radially extending protrusions (31, 31'), which are respectively formed on the outer circumferences of the two grinding discs (2, 3) in a regularly distributed manner.

16. Coffee machine having at least one grinding mill (1) according to any one of claims 1 to 13.

17. The coffee machine according to claim 16, characterized in that The coffee machine is a fully automatic coffee machine.

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