Coffee grinding machine with improved hopper engagement and opening / closing device

Abstract

A coffee grinding machine (1) is described, said machine comprising a hopper (2) for containing coffee beans to be ground and an engagement seat (15) configured to allow coupling of the hopper to the coffee grinding machine, wherein the hopper comprises an outlet mouth (2B) and a device (20) for closing and opening the outlet mouth, wherein the device for closing and opening the outlet mouth comprises a fixed member (30) substantially integral with the hopper and a movable shutter member (40, 50) with a manual control member (46) for manoeuvring the shutter member into an open or closed position, wherein the manual control member is configured to interact with the engagement seat (15, 151) and / or with the fixed member (30) so as to close the movable shutter member while the hopper is rotated in a first direction for disengaging it from the engagement seat.

Description

[0001] Coffee grinding machine with improved hopper engagement and opening / closing device

[0002] BACKGROUND

[0003] The present invention relates to a machine for grinding coffee beans. The machine for grinding coffee beans may be a separate machine or may be incorporated in an at least partly automatic machine for the production of coffee-based beverages. Such a machine is also known simply as a "coffee grinding machine", "coffee grinder" or "mill". In particular, it relates to a coffee grinding machine with an improved device for engagement and opening of the hopper.

[0004] PRIOR ART

[0005] Two categories of coffee grinding machines are known: one category uses volumetric dosing and has a storage tank, while the other category is of the "on demand" type, i.e. with instantaneous dosing, but without storage of the ground coffee. The present invention relates to both categories of machine, but preferably to coffee grinding machines of the “on demand” type, with instantaneous dosing, but without storage of the ground coffee.

[0006] In the coffee grinding machines, the coffee beans to be ground are contained in a hopper located on top of the coffee grinding machine. The hopper is filled with coffee beans via a top opening. The hopper also has a bottom opening for allowing the coffee beans to reach, by means of gravity, the grinding chamber.

[0007] Usually, the hopper is a component which is removable from the rest of the coffee grinding machine. The hopper, therefore, may be engaged or disengaged, for example in order to clean it or keep the coffee beans in a cool place.

[0008] In the known coffee grinding machines, engagement of the hopper is performed by means of vertical insertion, a form-fit coupling or rotation However, the possibility of operating the coffee grinder only with the hopper engaged is not always realized by means of operation of a microswitch or other sensor. This is often achieved by means of a mechanical locking system which requires the use of a tool in order to be removed.

[0009] As regards, instead, opening thereof, in the existing applications, plastic or metal tongues or spoon-shaped components which are rotationally operated are used.

[0010] AU 2009240812 A1 discloses a coffee grinding machine.

[0011] SUMMARY OF THE INVENTION

[0012] The Applicant has carefully examined the known coffee grinding machines.

[0013] The solution in which tongues are used allows opening and closing of the hopper by means of engagement or disengagement thereof into / from the coffee through-flow section.

[0014] With the solution comprising a spoon component, instead, the hopper may be opened and closed by means of rotation thereof between an opening point and closing point.

[0015] The Applicant is of the opinion that, in the coffee grinders for domestic or professional use, the system for engaging and opening the hopper has a very important role.

[0016] In particular, the Applicant has defined the aim of obtaining at least one of the following characteristics:

[0017] - not allowing the coffee grinding machine to be started unless the hopper is correctly engaged;

[0018] - not allowing the hopper to be disengaged unless the opening at the bottom has been closed beforehand;

[0019] - ensuring that as few grammes of coffee beans as possible remain between the hopper closure and the grinding chamber entry point; - allowing emptying, by means of grinding, of the downstream hopper channel also when the hopper is closed; and

[0020] - facilitating the user of the hopper and, more generally, of the coffee grinding machine.

[0021] In order to obtain at least one of the aforementioned characteristics, the Applicant has defined the aim of providing a hopper engagement system which is simple and easy to operate, but which at the same time is able to comply with the safety and operating requirements of the apparatus.

[0022] According to the present invention, a coffee grinding machine is provided, said machine comprising a hopper for containing coffee beans to be ground and an engagement seat configured to allow coupling of the hopper to the coffee grinding machine, wherein the hopper comprises an outlet mouth and a device for closing and opening the outlet mouth, wherein the device for closing and opening the outlet mouth comprises a fixed member substantially integral with the hopper and a movable shutter member with a manual control member for manoeuvring the shutter member into an open or closed position, wherein the manual control member is configured to interact with the engagement seat and / or with the fixed part so as to close the movable shutter member while the hopper is rotated in a first direction for disengaging it from the engagement seat.

[0023] According to embodiments, the shutter member comprises a plurality of tongues movable between a first position and a second position, wherein an opening in the bottom of the fixed part is closed and prevents the passage of coffee beans into a grinding group of the coffee grinding machine.

[0024] According to embodiments, the shutter member comprises a movable part, configured to perform a rotational movement with respect to the fixed part and to displace the shutter tongues from the first position into the second position and vice versa.

[0025] According to embodiments, the manual control member comprises a control lever integral with a movable part of the shutter member.

[0026] According to embodiments, the engagement seat comprises a first stop and a second stop for limiting the rotational movement of the control lever and for forcing the control lever to arrange the tongues in the closed position.

[0027] According to embodiments, while the hopper is rotated in the first direction to disengage it from the coupling seat, the second stop and the control lever remain in mutual contact to bring the shutter tongues into the closed position.

[0028] According to embodiments, the machine also comprises a safety activation and deactivation system which prevents the coffee grinding machine from functioning when the hopper is not correctly engaged.

[0029] According to embodiments, the system comprises a Reed safety sensor and a corresponding Reed sensor activation magnet, wherein the activation magnet of the Reed sensor is integral with the fixed part of the device and wherein the Reed sensor is integral with the machine.

[0030] According to embodiments, each of the shutter tongues substantially has a triangular shape with a base and a vertex.

[0031] According to embodiments, each of the shutter tongues comprises a first downward-facing protruding rotation pin, which is located substantially at one end of the side of each shutter tongue, wherein each of the shutter tongues is hinged to the fixed member through the respective rotation pin which engages a respective hole on a bottom of the fixed member.

[0032] According to embodiments, each of the shutter tongues comprises a second cam pin, wherein the second cam pin is arranged substantially at an intermediate position of the base of each shutter tongue, wherein each of the cam pins is configured to engage a slot of the mobile shutter member.

[0033] According to embodiments, the fixed member comprises teeth protruding radially from a lateral surface of said fixed member and wherein the engagement seat comprises longitudinal grooves configured to cooperate with the teeth, wherein the coupling between the radially projecting teeth and the grooves determines the insertion and extraction position of the hopper with respect to the insertion seat.

[0034] The invention, in another aspect, concerns, in a coffee grinding machine, a method for disengaging a hopper from a hopper disengagement seat of the coffee grinder machine, wherein the hopper comprises an outlet mouth and a device for closing and opening the outlet mouth, wherein the device for closing and opening the outlet mouth comprises a fixed member substantially integral with the hopper and a movable shutter member with a manual control member for maneuvering the shutter member into an open or closed position, wherein the manual control member is configured to interact with the engagement seat and / or with the fixed part wherein if the shutter member is in the open position, the method comprises the step of rotating the hopper in a first direction so that the manual control member remains in contact with the engaging seat so that, during the rotation of the hopper, the mobile shutter member rotates with respect to the hopper and closes the outlet mouth.

[0035] According to embodiments, the manual control member comprises a control lever integral with a mobile part of the shutter member and wherein the engaging seat comprises a window with a first stop and a second stop to limit the travel of the control lever and wherein the step of rotating the hopper in a first direction comprises the step of rotating the hopper in such a way that the control lever remains against the second stop so as to close the outlet mouth of the hopper during its rotation.

[0036] BRIEF DESCRIPTION OF THE FIGURES The present invention will become clearer from the following description, provided by way of a non-limiting example, to be read with reference to the accompanying drawings, in which:

[0037] - Fig. 1 .1 shows an example of a coffee grinding machine according to the present invention;

[0038] - Fig. 1.2 shows a longitudinally sectioned view of the machine according to Fig. 1.1 ;

[0039] - Fig. 2 is a cross-sectional view of the hopper and the hopper engagement and opening / closing device according to the invention;

[0040] - Fig. 3 is an exploded view of the hopper engagement and opening / closing device according to the invention;

[0041] - Figs. 4.1 and 4.2 are views of the fixed part of the device according to the invention;

[0042] - Figs. 5.1 and 5.2 are two views of the movable part of the device according to the invention;

[0043] - Fig. 6.1 is an axonometric view, from below, of the movable part (with tongues) fixed to the outlet mouth of the hopper;

[0044] - Fig. 6.2 is an axonometric view, from below, of the device according to the invention fixed to the outlet mouth of the hopper;

[0045] - Figs. 7.1 , 7.2 and 7.3 show the steps for insertion of the hopper and rotation for engagement of the hopper, and the hopper completely engaged;

[0046] - Figs. 8.1 and 8.2 show the opening and closing of the hopper;

[0047] - Fig. 9.1 shows the rotation action for disengagement of the hopper;

[0048] - Fig. 9.2 shows the action of disengagement and automatic closing of the hopper mouth;

[0049] - Fig. 10 shows how it is possible to remove the hopper only if completely disengaged; and - Figs. 11.1 and 11.2 illustrate operation of the activation and deactivation system in an axonometric view, from below, of the movable part (with tongues) fixed to the outlet mouth of the hopper;

[0050] DETAILED DESCRIPTION

[0051] Fig. 1.1 shows, purely by way of example, a coffee grinding machine

[0052] 1 according to the present invention; Fig. 1 .2 is a longitudinally sectioned view through the machine shown in Fig. 1.1 , which shows some of the main components. Obviously, a machine according to the present invention may assume any form, also entirely different from that shown in Figs. 1.1 and 1.2. Since the present invention concerns only some components of the machine, other components not essential for understanding of the invention will not be described and / or illustrated.

[0053] The machine 1 according to the present invention comprises a hopper

[0054] 2 for containing a quantity of coffee beans to be ground, a grinding group

[0055] 3 for grinding the coffee beans received from the hopper 2, a through- flow channel 4 for the ground coffee and an outlet channel 5 for the ground coffee so as to convey the coffee powder towards a receiving container. Typically, the receiving container is a filter 10 of a filter holder 11.

[0056] The machine 1 according to Figs. 1.1 and 1.2 also comprises a ring nut 12 for adjusting the fineness of the ground coffee.

[0057] The aforementioned figures also show the machine body 8, the motor 6 with drive belt 7 for rotating the burrs with respect to each other. The machine body 8 may be at least partially made of metal.

[0058] The coffee grinding machine 1 may comprise a support 13 for supporting the filter holder 11 in the correct position, so that the ground coffee is directed towards the filter 10 supported by the filter holder 11. The support 13 may be adjustable heightwise as indicated by the double arrow in Fig. 1.1. The hopper 2 is configured to contain a quantity of coffee beans to be ground. It may have any form, but typically has a top loading opening 2A for loading the coffee beans and a bottom outlet mouth 2B for feeding the coffee beans towards the burr group 3.

[0059] A device 20 for opening / closing the outlet mouth 2B is arranged at the outlet mouth 2B of the hopper 2.

[0060] As shown in Fig. 2 and in the exploded view of Fig. 3, the closing device 20 comprises three main parts: (i) a fixed part 30 substantially integral with the hopper 2, (ii) a movable part 40 which is free to rotate inside the fixed part 30 and which may be operated by the user, and (iii) shutter tongues 50 which, operated by the movable part 40, form a shutter-type closing system for the zone through which the coffee beans pass. According to one embodiment, there are six shutter tongues 50. However, according to other embodiments, they could consist of a greater or smaller number.

[0061] Figures 4.1 and 4.2 show two images of the fixed part 30. In the embodiment shown, the fixed part 30 has a roughly cup-shaped form with an upper rim 31 projecting outwards. The bottom 32 of the fixed part 30 comprises a central hole 33. Holes 34 (for example blind holes), the function of which will be clarified below, are angularly arranged around the central hole 33, circumferentially equally spaced from each other. A portion of the side wall 35 of the fixed part 30 is open and forms a first window 36. The sides of the window 36 are indicated by the numbers 361 and 362.

[0062] As shown in Figures 4.1 and 4.2, the fixed part 30 may also comprise one or more teeth 37 projecting radially from the side surface 35 thereof, for example in the vicinity of the projecting rim 31 .

[0063] Finally, the fixed part 30 may also comprise snap-engaging fasteners 38 for engagement with the outlet mouth 2B of the hopper 2 and for keeping the movable part 40 in position. The movable part 40 is housed inside the fixed part 30 and has a roughly annular shape with a circular opening 43 at the bottom 42. The part of the bottom 42 around the circular opening 43 also comprises a plurality of slots 49. The number of slots 49 corresponds to the number of tongues 50.

[0064] The movable part 40 also comprises a control lever 46 for rotating the movable part 40 with respect to the fixed part 30. The amplitude of the rotation is determined by the window 36 in the side wall 35 of the fixed part 30.

[0065] Each of the shutter tongues 50 has a substantially triangular shape with a base and a vertex.

[0066] Each of the shutter tongues 50 has a first rotation pin 54, visible in Fig. 3 and Fig. 6.1. The rotation pin 54 projects downwardly and is located substantially at one end of the side of each tongue 50. Each of the shutter tongues 50 is hinged with the fixed part 30 by means of the respective rotation pin 54 which engages inside one of the holes 34 on the bottom 32 of the fixed part 30.

[0067] Each of the shutter tongues 50 also comprises a second cam pin 59, projecting in the opposite direction to the rotation pin 54. The cam pin 59 is arranged substantially in an intermediate position of the base of the tongue 50. Each one of the cam pins 59 is configured to engage inside one of the slots 49 of the movable part 40. The shape of the slots 49 determines the path and therefore the movement of the shutter tongues 50.

[0068] When the control lever 46 is rotated in one direction or the other, the movable part 40 and, together with it, the tongues 50 are rotated. In other words, when the control lever 46 is operated in a clockwise direction, the shutter tongues 50 move towards each other (their vertices tend to move closer) and close substantially the central hole 33 of the fixed part; on the other hand, when the control lever 46 is operated in an anti-clockwise direction, the shutter tongues 50 move away from each other (their vertices tend to separate) and free the central hole 33 in the fixed part 30.

[0069] The coffee grinding machine 1 according to the present invention comprises an engagement seat 15 configured to receive the hopper 2 and in particular the device 20 for opening / closing the outlet mouth of the hopper 2. The engagement seat 15, as shown in Figures 7.1 , 7.2 and 7.3, comprises essentially a circular collar projecting upwards. The circular collar comprises a front window 151 configured essentially to be superimposed on the opening 36 of the fixed part 30 when the hopper 2 is correctly engaged.

[0070] The engagement seat also comprises longitudinal grooves 157 in the internal wall of the circular collar. The number, position and size of the longitudinal grooves 157 substantially corresponds to the number, position and size of the teeth 37 projecting radially from the side surface 35 of the fixed part 30.

[0071] As will become clear below, the engagement between the radially projecting teeth 37 and the grooves 157 determines the position for insertion and extraction of the hopper into / from the engagement seat 15.

[0072] Fig. 7.1 shows the step where the hopper 2 is inserted inside the engagement seat 15. The movement is simple and consists merely of a downwards displacement, as indicated by the arrow V.

[0073] Fig. 7.2 shows the configuration at the moment when a rotation of the hopper 2 in the clockwise direction is started in order to engage the hopper 2 with the machine 1. In this case also, the movement is simple for the user since it consists of a screwing movement with rotation through a few degrees.

[0074] Fig. 7.3 shows the configuration where the hopper 2 is completely engaged. As is clear when comparing Figures 7.1 , 7.2 and 7.3, the control lever 46, when the hopper 2 is inserted and before it is engaged by rotating it clockwise, is in the position at the right-hand end of the window 151 . At the end of engagement of the hopper 2, considering the hopper 2 has been rotated clockwise (keeping the control lever 46 stationary with respect to the hopper 2), the control lever 46 will be located at the lefthand end of the window 151 .

[0075] From the position shown in Fig. 7.3, with the hopper 2 engaged and the tongues 50 in the closed position, in order to open the mouth of the hopper and therefore allow the coffee beans to reach the burr group 3, it will be sufficient to rotate the control lever 46 in the anti-clockwise direction, as indicated in Fig. 8.1 by means of an arrow pointing towards the right. The rotation in an anti-clockwise direction moves the control lever 46 from the left-hand contact position (end-of-travel stop 151a) into the right-hand contact position (end-of-travel stop 151 b). The bottom part of Fig. 8.1 shows the tongues 50 which, after rotation of the control lever 46 in the anti-clockwise direction, are retracted towards the periphery of the circular opening 43 and leave the said opening free.

[0076] In order to close the outlet opening of the hopper 2 it is required to rotate the control lever 46 in the clockwise direction, as indicated by arrow pointing towards the left in Fig. 8.2, into the left-hand stop position 151 a of the window 151. In this position, the tongues 50 substantially entirely close the circular opening.

[0077] From the position shown in Fig. 8.2 (outlet mouth closed, control lever 46 towards the left and hopper 2 engaged), the hopper 2 may be disengaged by means of a simple rotation in the anti-clockwise rotation of the hopper 2, without moving the control lever 46. This situation is shown in Fig. 9.1 .

[0078] After disengaging the hopper 2, still with the control lever 46 in the position making contact against the right-hand edge 151 b of the window 151 (and therefore with the tongues 50 in the closed configuration), the hopper 2 may be extracted, by displacing it upwards. This situation is shown in Fig. 9.2.

[0079] A peculiar aspect of the present invention is the fact that extraction of the hopper 2 cannot be performed with the outlet mouth open. In fact, if a user were to disengage the hopper 2 and extract it starting from the configuration shown in Fig. 8.1 (hopper engaged, outlet mouth open, control lever 46 to the right), he / she would have to rotate the hopper 2 in the anti-clockwise direction. During this rotational movement of the hopper 2 in an anti-clockwise direction, the control lever 46 would remain in contact against the right-hand edge of the window 151. Therefore, during the rotational movement of the hopper 2, there would be a relative movement of the movable part 40 with respect to the fixed part 30 and closing of the outlet mouth of the hopper would occur automatically. Extraction of the hopper 2 would be possible only when the outlet mouth is closed.

[0080] Therefore, in short, the hopper 2 may be disengaged completely only when it is closed. When the hopper is engaged, it may be opened and closed as required by simply moving the control lever 46 in either direction.

[0081] Fig. 10 is a view from below and shows how it is possible to extract the hopper 2 only if it is completely disengaged and closed. From Figure 10 it can be seen that there must be a correspondence between the teeth 37 projecting from the side surface 35 of the fixed part 30 and the grooves 157 in the inner surface of the engagement seat 15.

[0082] The device 20 according to the invention obtains at least the following advantages: the hopper 2 cannot be disengaged unless the opening of the outlet mouth has been closed beforehand; in fact, by means of contact against the movable part in the unlocking direction, during disengagement an automatic closing movement of the tongues 50 occurs; the configuration is such that only a few coffee beans remain between the hopper closure and the burr group 3; in fact the device 20 is substantially at the lowest point of the hopper and therefore is able to remain in any case close to the burr group 3; emptying, by means of grinding, of the downstream channel of the hopper 2 is allowed also when the hopper is closed; and use of the hopper 2 and, more generally, of the coffee grinding machine 1 is simple and easy.

[0083] According to an embodiment of the present invention, the device 20 comprises a safety activation and deactivation system which prevents grinding unless the hopper 2 is correctly engaged. This solution is shown in Figures 11.1 and 11.2. The system comprises a Reed safety sensor

[0084] 60 and a corresponding magnet 61 for activation of the Reed sensor. According to the embodiment shown, the Reed sensor activation magnet

[0085] 61 is integral with the fixed part 30 of the device 20. The Reed sensor 60 is integral with the machine 1 in a predetermined position.

[0086] Fig. 11.1 shows the position of the activation magnet 61 when the hopper 2 is inserted (Fig. 7.1 ). In this position the magnet 61 does not activate the Reed sensor 60. Therefore the motor 6 does not start even if the pushbutton 9 for activating the grinding process is pressed.

[0087] Fig. 11 .2 shows the position of the activation magnet 61 once the hopper 2 has been engaged (Fig. 7.3). In this position, the magnet 61 activates the Reed sensor 60 and therefore the motor 6 may be activated.

Claims

CLAIMS1 . A coffee grinding machine (1 ) comprising a hopper (2) for containing coffee beans to be ground and an engagement seat (15) configured to allow coupling of the hopper to the coffee grinding machine (1 ), wherein the hopper (2) comprises an outlet mouth (2B) and a device (20) for closing and opening the outlet mouth, wherein the device (20) for closing and opening the outlet mouth comprises a fixed member (30) substantially integral with the hopper (2) and a movable shutter member (40, 50) with a manual control member (46) for manoeuvring the shutter member into an open or closed position, wherein the manual control member (46) is configured to interact with the engagement seat (15, 151 ) and / or with the fixed part (30, 36) so as to close the movable shutter member (40, 50) while the hopper (2) is rotated in a first direction for disengaging it from the engagement seat (15).

2. The coffee grinding machine (1 ) of claim 1 , wherein the shutter member comprises a plurality of shutter tongues (50) movable between a first position and a second position wherein an opening (33) in the bottom of the fixed part (30) is closed and prevents the passage of coffee beans into a grinding group (3) of the coffee grinding machine (1 ).

3. The coffee grinding machine (1 ) of claim 2, wherein the shutter member comprises a movable part (40), configured to perform a rotational movement with respect to the fixed part and to displace the tongues (50) from the first position into the second position and vice versa.

4. The coffee grinding machine (1 ) according to any one of the preceding claims, wherein the manual control member (46) comprises a control lever (46) integral with a movable part (40) of the shutter member.

5. The coffee grinding machine (1 ) of claim 4, wherein the engagement seat (151 ) comprises a first stop (151 a) and a second stop (151 b) for limiting the rotational movement of the control lever (46) and forcing the control lever (46) to arrange the tongues in the closed position.

6. The coffee grinding machine (1 ) according to claim 4 or 5, wherein while the hopper (2) is rotated in the first direction to disengage it from the engagement seat (15), the second stop (151 b) and the control lever (46) remain in mutual contact to bring the shutter tongues (50) into the closing position.

7. The coffee grinder machine (1 ) of any of the previous claims, further comprising a safety activation and deactivation system which prevents the operation of the coffee grinding machine when the hopper (2) is not correctly engaged.

8. The coffee grinder machine (1 ) of claim 7, wherein the system comprises a Reed safety sensor (60) and a corresponding Reed sensor activation magnet (61 ), wherein the activation magnet of the Reed sensor is integral with the fixed part (30) of the device (20) and wherein the Reed sensor (60) is integral with the machine (1 ).

9. The coffee grinder machine (1 ) of any of claims 2-8, wherein each of the shutter tongues (50) substantially has a triangular shape with a base and a vertex.

10. The coffee grinder machine (1 ) of claim 9, wherein each of the shutter tongues (50) comprises a first downward-facing protruding rotation pin (54), which is located substantially at one end of the side of each shutter tongue (50), wherein each of the shutter tongues (50) is hinged to the fixed member (30) through the respective rotation pin (54) which engages a respective hole (34) on a bottom (32) of the fixed member (30).11 . The coffee grinder machine (1 ) of claim 9 or 10, wherein each of the shutter tongues (50) comprises a second cam pin (59), wherein the second cam pin (59) is arranged substantially at an intermediate position of the base of each shutter tongue (50), wherein each of the cam pins (59) is configured to engage a slot (49) of the mobile shutter member (40).

12. The coffee grinder machine (1 ) of any of the preceding claims, wherein the fixed member (30) comprises teeth (37) protruding radially from a lateral surface (35) of said fixed member and wherein the engagement seat (15, 151 ) comprises longitudinal grooves (157) configured to cooperate with the teeth (37), wherein the coupling between the radially projecting teeth (37) and the grooves (157) determines the insertion and extraction position of the hopper with respect to the insertion seat (15).

13. In a coffee grinding machine (1 ), a method for disengaging a hopper (2) from a hopper disengagement seat of the coffee grinder machine (1 ), wherein the hopper (2) comprises an outlet mouth (2B) and a device (20) for closing and opening the outlet mouth, wherein the device (20) for closing and opening the outlet mouth comprises a fixed member (30) substantially integral with the hopper (2) and a movable shutter member (40, 50) with a manual control member (46) for manoeuvring the shutter member into an open or closed position, wherein the manual control member (46) is configured to interact with the engagement seat (15, 151 ) and / or with the fixed part (30, 36), wherein if the shutter member (40, 50) is in the open position, the method comprises the step of rotating the hopper (2) in a first direction so that the manual control member (46) remains in contact with the engaging seat (15,151 ) so that, during the rotation of the hopper (2), the mobile shutter member (40, 50) rotates with respect to the hopper and closes the outlet mouth.

14. The method of claim 13, wherein the manual control member (46) comprises a control lever (46) integral with a mobile part (40) of the shutter member and wherein the engaging seat comprises a window (151 ) with a first stop (151a) and a second stop (151b) to limit the travel of the control lever (46) and wherein the step of rotating the hopper (2) in a first direction comprises the step of rotating the hopper (2) in such a way that the control lever (46) remains against the second stop (151 b) so as to close the outlet mouth of the hopper during its rotation.

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