Improved grinding machine preferably for granular food

Abstract

Grinding machine, preferably for granular foods, comprising a first and a second motorized disc movable by rotation with respect to an axis and comprising facing and axially spaced teeth so as to define a chamber in which, in use, the granular foods are ground by exiting through a radial slot defined between the teeth; a duct for feeding the granular foods extending at least partly parallel to the axis and connected at the inlet to the chamber; an elongated body movable by rotation with respect to the axis and extending longitudinally from the chamber at least partly inside the duct, and comprising a radially raised edge surrounding at least a section of said body extending longitudinally from an end portion of the body on the side of the duct towards the chamber, said edge being inclined with respect to the axis to define a guide for the granular materials in the duct so that, in use, a rotation of the elongated body causes an advancement of a metered quantity of granular materials towards the chamber; and the elongated body also having a wall extending radially at least partially inside the chamber so that a rotation of the elongated body also causes a movement of the granular materials in the chamber actuated by the wall in a direction consistent with the direction of rotation of the elongated body

Description

[0001] “IMPROVED GRINDING MACHINE PREFERABLY FOR GRANULAR FOOD”

[0002] DESCRIPTION

[0003] TECHNICAL FIELD

[0004] The present invention relates to the field of machines for grinding granular foods, e.g. coffee beans, spices, dried fruit, etc., in particular a grinding machine comprising a pair of superimposed flat or concave / convex disc grinders, both of which are rotating, and an improved dosing device for the granular foods fed into the grinding machine.

[0005] STATE OF THE ART

[0006] In the field of machines for grinding granular foods, e.g., coffee beans, spices, etc., and in particular in the sector of countertop grinding machines used, e.g., in bars, restaurants, etc., solutions with an inlet port for the granular foods, e.g., coming from a container or a hopper on board the machine, a supply duct into which the granular foods coming from the inlet port are discharged, and a grinding chamber that receives the granular foods to be ground coming from the supply duct, are widely used. Typically, inside the grinding chamber there is a pair of facing grinding discs, preferably flat or concave / convex, in which one or both discs rotate, e.g., each connected via torque transmission to an electric motor on board the grinding machine. Currently available commercial solutions feature construction configurations in which the feed duct is inclined relative to the grinding machine's support surface or perpendicular to allow the granular materials to fall by gravity into the grinding chamber. However, the free fall of the granular materials to be ground through the feed duct into the grinding chamber has numerous disadvantages. For example, the granular materials, falling by gravity, accumulate inside the duct, risking clogging and interrupting the flow of granular materials into the grinding chamber. Furthermore, the quantity of granular materials in the grinding chamber varies from time to time based on their arrangement within the grinding chamber, thus varying the quantity of granular materials ground in a given time interval, and thus also the yield of the final product, e.g., coffee.

[0007] It is therefore always a pressing need to create solutions that are simple in construction and that allow for the regulation of the quantity of granular feed introduced into the grinding chamber. This not only prevents possible blockages in the feed duct, thus avoiding unwanted maintenance, but also improves the machine's production capacity and the yield of the finished product.

[0008] SCOPES AND BRIEF DESCRIPTION OF THE INVENTION

[0009] The present invention aims to meet at least partially the above-mentioned needs, achieving this scope by means of a grinding machine, preferably for granular foods, according to claim 1.

[0010] According to a preferred embodiment of the present invention, a grinding machine, preferably for granular foods such as coffee, spices, etc., is presented. The machine has an optimized design that provides the regulation of the flow of granular foods sent to the grinding unit through the use of a simple and compact mechanical component, located upstream of the components for grinding the granular foods. This minimizes the risk of accumulation and / or clogging of the duct into which the granular material is fed prior to grinding, while simultaneously improving the production capacity of the grinding machine by grinding a measured quantity of granular materials, thus also improving the yield of the finished product. In particular, to achieve this result, the following description presents a grinding machine comprising a first and second motorized disc housed in a machine body and rotating about a preferably common axis. These discs comprise facing and axially spaced teeth so as to define a chamber in which, in use, the granular foods are ground by exiting transversely to the axis through a radial slot defined between the teeth. To feed this chamber with granular materials to be ground, the grinding machine also comprises a granular food supply duct extending at least partially parallel to the axis and connected to the chamber's inlet. In this way, for example in the case of a top-loading grinding machine, the chamber is fed by granular foods that fall by gravity through the supply duct, e.g., fed by a user into an apical area of the machine where there is an inlet port or preferably a hopper. According to the invention, the grinding machine comprises an elongated body that is movable by rotation with respect to the axis and extends longitudinally from the chamber at least partially into the internal duct. For example, this elongated body has a first longitudinal end connected to one of the first and second discs so as to be integral with one of them for rotation. It should be noted that the first and second discs can each be driven by a respective electric motor on board the grinding machine so as to have different rotation speeds but also a concordant or discordant direction of rotation. Furthermore, the elongated body has a second end, longitudinally opposite to the first end, on which there is a radially raised edge, i.e. this edge protrudes into the radial space between the internal wall of the supply duct and the elongated body. In particular, this edge is shaped so as to surround at least a section of the elongated body, extending longitudinally from a portion of the second end of the body towards the chamber, in particular in a manner inclined with respect to the axis of rotation of the discs, e.g. with a helical profile, for example, defining a screw conveyor. In this way, the granular materials that fall by gravity into the feed duct before being deposited in the chamber are intercepted by the elongated body via the raised edge, on which they settle. As can be understood, the raised edge defines a guide for the granular materials in the feed duct, and therefore its shape is exploited such that a rotation of the elongated body causes a measured quantity of granular materials to advance towards the chamber. Furthermore, the raised edge is interrupted at a section of the elongated body so that the granular foods located at one end of the edge are pushed by those located further back during the rotation of the elongated body. In this way, each rotation of the elongated body corresponds to a measured quantity of granular materials that falls by gravity into the chamber. According to a further aspect of the present invention, the elongated body further comprises at least one wall, preferably three equidistant from each other, arranged on the elongated body so as to extend radially at least partially within the chamber. This wall is further exploited while the grinding machine is in operation so that rotation of the elongated body also causes movement of the granular foodstuffs present in the chamber in a direction consistent with the direction of rotation of the elongated body. In particular, the wall, rotating integrally with the elongated body, contacts a portion of the granular food, exerting a thrust force on them that is transferred to adjacent granular food, causing them to advance in the direction of rotation of the elongated body. In this way, it is possible to favor the occupation of radially peripheral areas in the chamber where granular materials, falling by gravity from the raised edge, would tend to settle with greater difficulty, accumulating in a portion of the chamber located at the bottom of the direction of fall, thus benefiting a more controllable production capacity of the grinding machine. According to a further aspect of the present invention, the elongated body is a mechanical component releasably mounted on board the grinding machine and can be supplied in a kit comprising a plurality of elongated bodies having different geometries and adapted based on the type and / or size of the granular food to be ground.

[0011] DESCRIPTION OF THE DRAWINGS

[0012] The construction and functional characteristics of the grinding machine, preferably for granular foods, can be better understood from the detailed description that follows, which refers to the attached figures representing a preferred and non-limiting embodiment, in wherein:

[0013] • Fig. 1 shows a perspective view of the grinding machine, preferably for granular foods, according to a preferred embodiment of the present invention, illustrating a first embodiment of a rotary grinding mechanism;

[0014] • Fig. 2 shows a front sectional view of a second embodiment of the rotary grinding mechanism for a grinding machine according to the present invention;

[0015] • Fig. 3 shows a side sectional view of the grinding mechanism of Fig. 2;

[0016] • Figs. 4 and 5 show, respectively, a front view of the elongated body and a front sectional view of the elongated body according to the preferred embodiment of Fig. 1; and

[0017] • Fig. 6 shows an exploded section of Figure 1.

[0018] DETTAILED DESCRIPTION OF THE INVENTION

[0019] According to a preferred embodiment of the present invention, Fig. 1 shows a perspective view of a grinding machine M for granular foods such as coffee beans, spices, dried fruit or other food substances, having an optimised construction configuration. Such machine has a body Ml shaped so as to house the machine components used to perform the grinding. This grinding machine is preferably but not limited to vertical loading, so that in an apical portion this machine has a shaped guide 1, preferably converging from top to bottom, having an inlet port la through which the granular foods to be ground are loaded into the body Ml of the grinding machine. Furthermore, the shaped guide 1 extends vertically having an outlet port lb facing a duct 2 for dispensing the granular foods into which the granular foods to be ground fall by gravity, e.g. loaded manually by a user through the input port la of the shaped guide. Furthermore, the grinding machine M comprises a cover 3 to which the shaped guide 1 is releasably constrained, e.g. rigidly constrained by screws (figure 2), and featuring a hole 4 in which the shaped guide 1 is at least partially inserted to access the duct 2 for dispensing the granular foods. This cover is used to avoid access from above to the components arranged inside the body of the grinding machine. Furthermore, the grinding machine M comprises a first and a second disc 6, 7 arranged so as to be both movable upon rotation with respect to the axis XI, e.g. arranged concentrically. In particular, these discs are used to grind the granular foods coming from the supply duct 2, for which they are arranged at a lower vertical height than the height at which such foods exit from the duct. To do this, the discs have facing teeth shaped so as to be axially spaced, i.e. parallel to the axis XI, defining a chamber 5 in which the granular foods to be ground coming from the supply duct 2 are deposited. In particular, this supply duct extends vertically, preferably parallel to the axis XI, having a first end facing the exit port lb of the shaped guide 1 so as to receive the granular foods, and a second end, longitudinally opposite to the first end, to which the first disc 6 is preferably constrained, from which the foods to be ground emerge and settle in the chamber 5. To deposit the granular foods inside this chamber, the first disc 6 has an axial hole 8, preferably concentric to the axis XI, through which the granular foods falling by gravity into the supply duct 2 are deposited in the chamber. Preferably, to facilitate the settling of granular foodstuffs inside chamber 5, the second end of the supply duct 2 has internal walls that extend divergently towards this chamber, thus reducing the risk of accumulation of granular foodstuffs and consequent blockages of the duct. Based on this construction configuration, the first grinding disc 6 extends radially from the end edge of the internal wall of the supply duct 2, i.e. the axial hole 8 has a diameter greater than or equal to the diameter of the second end of the supply duct. For example, in the embodiment of figure 1, the second end of the supply duct 2 has an annular projection B within which the disc 6 is radially centered. Alternatively, in the embodiment of figure 2, the second end of the supply duct 2 has a flanged edge shaped so as to define a circumferential recess on which a corresponding projecting circumferential edge 6a of the first grinding disc is axially engaged, so as to define an interference fit such as to constrain the first grinding disc to the supply duct 2 against rotation. Furthermore, a first rolling bearing 15 is mounted around a section of the supply duct 2 preferably towards the second end, e.g. radially interposed between the supply duct and a first flanged ring 15b which is in turn rigidly constrained to the body of the machine, so that the supply duct 2 and the first disk 6 are rotationally movable with respect to the central body of the machine which remains stationary during use. As shown in more detail in Fig. 3, the first and second discs 6, 7 are rotated, preferably each by a motor, controlled in turn, e.g., by a corresponding inverter or by a single inverter through which the motors are driven at the same angular speed but with opposite directions of rotation. In this preferred embodiment, the first disc 6 can be considered as the upper disc, while the second disc 7 is considered as the lower disc. In particular, the rotation of the upper disc is actuated by an electric motor 9 connected in torque transmission to this disc, e.g., by a transmission with an endless flexible element, and in use this disc rotates at a first non-zero speed. Preferably, the electric motor 9 is placed next to the discs 6, 7. For example, in order for the first disc 6 to be rotated by the first electric motor 9, the grinding machine M comprises a first pulley 11 that surrounds the supply duct 2 and to which it is rigidly blocked from rotation. Preferably, a second pulley 12 can be mounted on the shaft of the electric motor 9 so that the electric motor 9 and the first disc 6 are connected in torque transmission via a belt 10 which connects the first and second pulleys 11, 12. Furthermore, a second rolling bearing 16 is provided mounted on a longitudinal bushing of the first pulley 11. The embodiment of figure 1 provides for the opening of the grinding machine M along a plane having trace T, as more clearly indicated in figure 6, to the detailed description of which reference is made. Alternatively, according to figure 2, the second rolling bearing 16 is interposed radially between the first pulley and a second flanged ring 16b which is in turn rigidly constrained to the body Ml of the machine. The lower disc 7 is instead arranged in a longitudinal position opposite the supply duct 2 with respect to the upper disc. Preferably, the lower disc also has an axial hole 17 and is rigidly fixed to a disc holder 18 arranged in a longitudinal position opposite the upper disc 6 with respect to the lower disc so as to cover the axial hole 17, i.e. the disc holder is arranged on the bottom side of the body Ml of the grinding machine, thus preventing the escape of granular food into the chamber 5 through this axial hole. Therefore, the second disc 7 and the disc holder 18 are rigidly blocked from rotation with respect to the axis XI and, in the embodiment of figure 1, the disc holder 18 also comprises a plurality of projections T that surround the disc 7 and define one or more radial openings for the expulsion of the ground material. Furthermore, to actuate the rotation of the lower disc 7, the disc holder 18 is in turn connected in torque transmission to a second electric motor 19 preferably arranged in a compartment next to that of the first motor 9. In particular, on the bottom of the body of the grinding machine a hole is made perpendicular to the axis XI through which the second motor 19 is mounted, which comprises a rotary drive shaft 20 rigidly connected to the disc holder 18. Preferably, to rigidly lock the drive shaft 20 and the disc holder 18, an interference or splined fit can be made. For example, the drive shaft 20 has a hole made transversely and preferably perpendicular to the axis XI, where this hole is arranged in use inside the axial seat of the disc holder 18 so that by means of a pin (not shown in the figure) arranged in this hole it is possible to achieve the interference fit. Preferably, a spacer 21 may be provided, placed between the disc holder 18 and a shoulder 22 on the end of the drive shaft 20 on the side of the electric motor 19. Preferably, to constrain the lower disc 7 from rotation to the disc holder 18, in the embodiment of figure 2, this disc holder may have a flanged edge shaped so as to define a circumferential recess on which a corresponding projecting circumferential edge 7a of the lower disc is axially engaged, so as to define an interference fit. In use, the first disc 6, i.e. the upper one, rotates at a different speed from that of the second disc 7, i.e. the lower one, and with the same direction of rotation. Preferably, the first and second electric motors 9, 19 may be actuated so that the first and second discs 6, 7 have discordant directions of rotation. Preferably, the two motors can rotate at different speeds and can be adjusted independently of each other to be able to appropriately adjust the relative speeds of the discs depending on the type of product to be ground. Even more preferably, for the purpose of reducing costs, a single inverter, for example placed under the first electric motor 9, controls the angular speed of both electric motors 9, 19, the corresponding directions of rotation being opposed either by means of an appropriate electrical connection or by means of a gear. In the latter case, except for the direction of rotation, the module of the relative speed does not change and is unitary when the electric motors 9, 19 are directly driven by the corresponding disc or the transmission ratio of the pulleys 11, 12. Therefore, in this embodiment, the angular speeds of the discs 9, 19 are dependent on each other. Furthermore, the relative speed between the discs can be varied, i.e. increased or decreased, during use. Therefore, based on this constructional configuration of the grinding machine, the granular foods are preferably introduced from above into the shaped guide and, falling by gravity through the supply duct 2, are deposited in the chamber 5 to be ground. The rotation of the first and second discs 6, 7 causes the breaking and grinding of the granular foods present inside the chamber 5. The ground foods exit radially from the chamber 5, preferably perpendicular to the axis XI, so as to be fed into an ejection duct 24 through which they are supplied to the user ready for use. In particular, to radially expel the ground foods from the chamber 5, the facing teeth of the first and second discs are axially spaced so as to define a radial slot 25 through which the ground foods exit during the rotation of the discs. In particular, the opening 24 faces the slot 25 so as to receive the ground product by centrifugal acceleration. Preferably, the projections T are shaped to carry ground powder inside the recess R towards the opening 24 during rotation. According to a further aspect of the present invention, to counteract the free fall due to gravity of the granular foods inside the supply duct 2 with the consequent risk of having accumulations and / or blockages of the duct, but above all to regulate the quantity of granular foods present inside the chamber 5 during use, an elongated body 27 is mounted on board this grinding machine which is used to regulate the flow of granular foods in the duct and facilitate the deposit of a dosed quantity of granular foods to be ground in the chamber 5. To obtain this result, the elongated body 27 has a first longitudinal end 27a rigidly constrained in use to the disc holder 18. In particular, the first longitudinal end is shaped so as to define a recessed seat 28 suitable for engaging on an axially protruding portion 18a of the disc holder parallel to the axis XI, defining a shape coupling. In this way, the elongated body 27 extends parallel to the axis, placing itself at least partially outside the chamber 5 inside the supply duct 2, i.e. passing through the axial hole 8 of the upper disk 6. As can be understood, the elongated body is constrained from rotation by the lower disk 7, i.e. movable from rotation with respect to the axis XI. Furthermore, the elongated body 27 has a second end 27b, longitudinally opposite to the first end 27a, on which there is a radially raised edge 29, i.e. this edge projects into the radial space between the internal wall of the supply duct and the elongated body. In particular, this edge 29 is shaped so as to surround at least a section of the elongated body 27, extending longitudinally from a portion of the second end of the body towards the chamber 5, in an inclined manner with respect to the axis XI, e.g. according to a helical profile defining e.g. a screw. In this way, the granular materials that fall by gravity into the supply duct 2 before settling in chamber 5 are intercepted by the elongated body 27 via the raised edge 29. In particular, the shape of this edge is used to guide the granular foods towards chamber 5, which, falling by gravity through the duct 2, rest on this edge. It should also be noted that the radial distance between the edge 29 and the internal wall of the supply duct 2 is less than the minimum size of the granular foods to be processed, so the edge counteracts the fall of the granular foods by gravity towards the chamber, which in turn accumulate above the raised edge 29, whose rotation synchronized with the disk 7 doses the granular material descending towards chamber 5. Preferably, the second end 27b of the elongated body is pointed so as to have vertically diverging walls defining slides to guide the granular materials towards the raised edge 29. As can be understood, the raised edge 29 defines a guide for the granular materials in the supply duct 2, and its shape is therefore exploited so that a rotation of the elongated body 27 causes an advancement of a dosed quantity of granular materials towards the chamber 5. This quantity, in the embodiment of figure 1, is further determined by a protruding or recessed helical profile of the duct 2. Based on the direction of rotation of the duct 2 and of the disc holder 18, the profile P and the raised edge 29 are made so that the helical principles tend to drag the granular material towards the chamber 5. Furthermore, the raised edge 29 is interrupted in a section of the elongated body still arranged inside the supply duct 2, so that the granular foods located on a terminal section of the edge are pushed by those located in a more rearward position during the rotation of the elongated body 27. In this way, a rotation of the elongated body 27 corresponds to a dosed quantity of granular materials that falls by gravity into the chamber 5. According to a further aspect of the present invention, the elongated body 27 also comprises at least one wall 30, preferably three equidistant at the angles, arranged on the first end 27a so as to extend radially at least partially inside the chamber 5. Furthermore, the wall 30 extends radially into the chamber 5 so as to leave an adequate radial space between this wall and the teeth of the respective discs so as to leave this radial space free for the passage of the granular material falling from the raised edge 29. This wall is further exploited while the machine is in operation. The grinding operation is such that a rotation of the elongated body 27 also causes the granular foods present in the chamber to move in a direction consistent with the direction of rotation of the elongated body. In particular, the wall 30, rotating in a manner integral with the elongated body 27, and in particular with the disc holder 18, contacts a portion of the granular foods, exerting a thrust force on them which is transferred to the adjacent ones, causing them to advance in the direction of rotation of the elongated body. In this way, it is possible to favor the occupation of radially peripheral areas in the chamber 5 in which the granular materials, falling by gravity from the raised edge 29, would tend to arrange themselves with greater difficulty, accumulating in a portion of the chamber located at the bottom of the direction of fall, to the benefit of a more controllable production capacity of the grinding machine M. Furthermore, the elongated body 27 is a separate component from the disc holder 18 to which it is releasably constrained. For example, the elongated body 27 may have a longitudinal through hole 31 parallel to the axis XI together with a recessed seat made on the end on the duct side to house a screw head. According to this construction solution, both the disc holder 18 and the drive shaft 20 are drilled concentrically to the longitudinal hole 31 so that they can be rigidly connected to each other in a releasable manner by means of a screw (not shown in the figure). In this latter solution, depending on the type and size of the granular foods to be ground, different elongated bodies may be mounted on board the grinding machine, for example featuring a different shape of the raised edge 29. For example, the raised edge may include a screw with a larger pitch if larger granular foods need to be processed, or a screw with a raised edge angled more downwards if granular foods with greater surface roughness need to be processed. Advantageously, the replacement or maintenance of the elongated body 29 is particularly easy since it is sufficient to remove the cover 3, preferably together with the shaped guide 1, so as to be able to access the supply duct 2 along which the elongated body extends towards the user. In this way, it is possible to remove the screw inserted inside the longitudinal hole 31 to disconnect the elongated body from the disc holder 18 and extract it from the supply duct 2.

[0020] The construction configuration of the preferred embodiment described above, i.e., with a vertical grinding axis, is advantageous in countertop applications such as in bars, restaurants, etc., but variants (not illustrated) can also be envisaged, in which it is possible to create a machine with a horizontal grinding disc rotation axis by rotating the main components shown in the figure by approximately 90° and making the necessary modifications.

[0021] Figure 6 shows a disassembled configuration of the embodiment shown in Figure 1. In particular, cover 3 houses the worm gear with pulleys 11, 12; and duct 2 with bearings 15, 16. A base of the body Ml houses the electric motors in corresponding compartments; and defines a recess R located above the electric motor 19 in which the disc holder 18 is housed. An annular projection F of the flanged ring 15b carries a ring seal 35 that contacts an internal surface of the recess R when the cover R is closed, thus sealing the chamber 5 and preventing ground powder from rising towards the interface plane, e.g., due to the fan effect. Depending on the shape of the casing, the interface plane can be replaced by any shape to separate the cover 3 from the base of the body Ml.

[0022] To allow easy assembly / disassembly of the cover 3, e.g., to replace the elongated element 29 or to clean the chamber 5, the connection between the electric motor 9 and the pulley 12 is rigid in rotation and free in axial translation, e.g., a splined coupling.

[0023] According to the embodiment of figure 1, the grinding machine M comprises an actuator controlled by an electronic control unit (not shown) to automatically adjust the relative axial position between the discs 6 and 7. Preferably, the actuator comprises a worm screw 40 powered by an electric motor not shown and meshing with a worm wheel 41 of the flanged ring 15b. The latter is also supported by the cover 3 via a threaded connection 42 so that, through the rotation of the worm wheel 41 in one direction or the opposite direction, the flanged ring 15b translates axially both towards and away from the disk 7.

[0024] According to one aspect of the present invention, for example, when the cover 3 is closed or when this automatic function is initiated via a command on a user interface, an electronic control unit is programmed to:

[0025] - Activate the rotation of one of the two disks 6, 7, preferably at a speed lower than the grinding speed - Perform a translation of the disk 6 by rotating the worm screw 40

[0026] When a rotation of the other disk 6, 7 above a predefined threshold is detected, it stops the translation or retracts the translation by a predefined amount.

[0027] Preferably, the above is implemented in the embodiment in which two inverters are present, one for each electric motor 9, 19, and the rotation of the disc whose motor is switched off (i.e., not powered) is detected, e.g., via an angle sensor or by detecting the current of the switched-off electric motor.

[0028] As illustrated in the figure, the inlet of the granular food product to be ground is substantially parallel to the rotation axis XI of the elongated element 29, but it is also possible for this inlet to be transverse, e.g., perpendicular to this rotation axis.

Claims

CLAIMS1. Grinding machine (M) preferably for granular foods comprising:- a first and a second motorized disk (6, 7) rotatably movable with respect to an axis (XI) and comprising facing and axially spaced teeth so as to define a chamber (5) in which in use the granular foods are ground by exiting through a radial slot (25) defined between the teeth;- a supply duct (2) for the granular foods extending at least in part parallel to the axis (XI) and connected at the inlet to the chamber (5);- an elongated body (27) rotatably movable with respect to the axis (XI) and extending longitudinally from the chamber (5) at least partly inside the duct (2), and comprising an edge (29) which surrounds at least a section of such body extending longitudinally from an end portion of the body on the duct side towards the chamber (5), such edge being inclined with respect to the axis (XI) to define a guide for the granular materials in the duct (2) so that in use a rotation of the elongated body (27) causes an advancement of a dosed quantity of granular materials towards the chamber (5).

2. A grinding machine (M) according to claim 1, comprising a cover (3) carrying one of the first and second motorized discs and removable from a base of the grinding machine (M), and the elongated body (27) being releasably coupled to one of the first and second motorized discs (6, 7) such that when the cover (3) is removed from the base, the elongated body is accessible for disassembly; a first and a second electric motor (9, 19) of the motorized discs (6, 7) remaining housed in the base when the cover (3) is disassembled from the base.

3. A grinding machine according to claim 2, wherein the cover (3) further carries a transmission for connecting in torque transmission one of said first and second electric motors (9, 19) and the motorized disc (6) carried by the cover (3).

4. A grinding machine according to one of claims 2 and 3, wherein it is defined betweenthe lid (3) and the base, a first portion (15b) carried by the lid (3) and a second portion (R) carried by the base, a sealing ring (35) being interposed between the first and second portion.

5. A grinding machine according to any of claims 2 to 4, wherein the lid (3) covers the first and second electric motors (9, 19).

6. A machine according to any of the preceding claims, comprising an inverter to which the first and second electric motors (9, 19) are connected so that they rotate in opposite directions and that an angular velocity adjustment from the inverter reaches the first and second electric motors so that the number of revolutions increases or decreases in accordance so that a ratio between the numbers of revolutions of the first and second electric motors remains constant as the regulation signal of the inverter varies.

7. A machine according to any of claims 1 to 5, comprising a first and a second inverter so as to control the rotation of the motorized discs (6, 7) independently of each other.

8. A grinding machine according to any of the preceding claims, further comprising a further edge (B) surrounding said edge (29) and rotated together with the other of the motorized discs (6, 7), the further edge (B) being inclined so that, during the rotation of the motorized discs (6, 7), both the edge (29) and the further edge (B) tend to push the granular food towards the chamber (5).

9. A grinding machine according to any of the preceding claims, wherein the elongated body (27) further has a wall (30) extending radially at least partly inside the chamber (5) so that a rotation of the elongated body further causes a movement of the granular materials in the chamber actuated by the wall in a direction consistent with the direction of rotation of the elongated body.

10. A grinding machine according to any of the preceding claims, wherein one of the motorized discs (6, 7) is configured to translate parallel to the axis (XI) and an electroniccontrol unit is programmed to control the rotation of one of the motorized discs, control the approach between the motorized discs, detect a rotation of the other of the motorized discs above a predefined threshold and stop the approach or control a separation between the motorized discs of a predefined distance.

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