Mixer and mixing method

Abstract

Described is a mixer for preparing mixtures by mixing flowable substances comprising a control unit and a supporting structure (2) which houses the control unit. The mixer also comprises a first mixing head (11) which can be coupled to a first container (21) for preparing a first mixture and a second mixing head (12) which can be coupled to a second container (22) for preparing a second mixture. The first mixing head (11) and the second mixing head (12) are both supported by the supporting structure (2) and are connected to the control unit, so that the control unit controls both the first mixing head (11) and the second mixing head (12).

Description

[0001] Mixer and mixing method

[0002] The invention relates to a mixer for mixing flowable substances, that is to say, in the fluid, liquid or creamy state, or in the solid state, in particular powders or granules.

[0003] The mixer according to the invention may in particular be used for producing paints, even though other applications may be planned.

[0004] The mixer according to the invention operates in batches, that is to say, it operates separately. That is to say, it is intended to be closed after having been filled with a predetermined quantity of substances to be mixed. At this point there is a mixing step, at the end of which the mixer can be moved to an open position for unloading a mixed product and then loading new substances to be mixed.

[0005] The invention also relates to a method for mixing flowable substances.

[0006] There are prior art mixers for paints, comprising a main body, generally in the shape of a parallelepiped, on a face of which there is a mixing head. A container containing the substances to be mixed may be fixed to the mixing head, so that the latter can mix the substances contained in the container to obtain a desired product.

[0007] The prior art mixers comprise a vertical support, positioned on the opposite side of the mixing head relative to the main body, in such a way that the mixing head is interposed between the main body and the vertical support. There is also a horizontal beam which joins the vertical support to the main body.

[0008] A defect of the prior art mixers is that their productivity is relatively low, since relatively long times are necessary for introducing into the mixer the substances to be mixed and for removing the mixed product from the mixer. During these times, the prior art mixer is stationary.

[0009] Moreover, the prior art mixers are not very versatile, in particular with regard to the installation layout. They may only be loaded or unloaded from the front, moving the container which contains the substances to be mixed along an infeed or outfeed direction perpendicular to the horizontal beam. This is due to the overall dimensions of the vertical support and of the main body, which prevent the container from being moved towards, or away from, the mixing head along a lateral direction.

[0010] Lastly, it is difficult to perform cleaning or maintenance operations on the mixing head in the prior art mixers, since the mixing head is positioned at a relatively great height and it is necessary to use a ladder to access it, which may result in risks of injury for the operator. These difficulties are all the more marked the greater the size of the mixer. In fact, the larger the mixer, the more difficult it is to access the head of mixing, which is positioned at a greater height.

[0011] An object of this invention is to improve the mixers and the methods for mixing flowable substances, particularly, but not exclusively, for preparing paints.

[0012] Another object is to provide a mixer for flowable substances, which has a good productivity and whose down times are reduced.

[0013] A further object is to provide a mixer for flowable substances on which it is easy to perform cleaning or maintenance operations.

[0014] Another object is to provide a mixer for flowable substances which has a good flexibility and is able to operate according to multiple layout configurations.

[0015] According to a first aspect of the invention, a mixer is provided for preparing mixtures by mixing flowable substances, comprising a control unit, a supporting structure which houses the control unit, a first mixing head which can be coupled to a first container for preparing a first mixture, a second mixing head which can be coupled to a second container for preparing a second mixture, wherein the first mixing head and the second mixing head are both supported by the supporting structure and are connected to the control unit, so that the control unit controls both the first mixing head and the second mixing head. The mixer according to the first aspect of the invention has a high productivity and allows the downtimes between one mixing step and the next mixing step to be reduced.

[0016] In effect, whilst the first mixing head works to prepare a mixture in the first container, the operator may act on the second container, which contains the mixture just prepared, to move it away from the mixer and replace it with a new second container having inside it the ingredients of a new mixture. This prevents the operator from remaining inactive for a long time whilst waiting for the mixture to be prepared.

[0017] Moreover, owing to the use of a shared supporting structure which supports both the first mixing head and the second mixing head, it is possible to reduce the costs and the dimensions of the mixer according to the invention, compared with the case in which two mixers of known type are used, each having a single mixing head.

[0018] In an embodiment, the first mixing head and the second mixing head are configured to be positioned in different operating conditions at the same instant.

[0019] The first mixing head and the second mixing head are therefore independent of each other.

[0020] Whilst one of the two mixing heads is active and is working to prepare a mixture by mixing two or more flowable substances, the other mixing head may be inactive (meaning that it is not mixing) for example because it is subject to loading / unloading, maintenance or cleaning operations.

[0021] This makes it possible to reduce downtimes and increase productivity.

[0022] In an embodiment, the first mixing head and the second mixing head are each delimited by a closing face designed to engage with the respective container for closing the latter.

[0023] The closing face may be flat or concave.

[0024] The first mixing head and the second mixing head each comprise a mixing tool which may protrude from the closing face and is rotatable about an axis of rotation for mixing at least two ingredients in the corresponding container.

[0025] Owing to the mixing tool, it is possible to effectively mix the ingredients introduced in each container, quickly obtaining uniform mixes.

[0026] The supporting structure may comprise a box-shaped body which houses the control unit.

[0027] The box-shaped body may have an approximately parallelepiped shape.

[0028] The first mixing head and the second mixing head may be positioned on respective opposite walls of the box-shaped body.

[0029] In this way, the first mixing head and the second mixing head are mounted in a balanced fashion on the supporting structure, which may support the first mixing head and the second mixing head without using supports located outside the box-shaped body and spaced from the latter.

[0030] Owing to the absence of supports spaced from the box-shaped body, the first container and the second container may be moved towards, and moved away from, the first mixing head and, respectively, the second mixing head, along respective directions of movement which can be freely selected depending on the spaces available in the factory in which the mixer is installed. This makes it possible to personalise the layout of the mixer and optimise the distribution of the spaces in the production plant.

[0031] In an embodiment, the mixer comprises a first guide for moving the first container towards, and moving the first container away from, the first mixing head along a first direction of movement.

[0032] The mixer also comprises a second guide for moving the second container towards, and moving the second container away from, the second mixing head along a second direction of movement.

[0033] The first guide and the second guide may be aligned with each other.

[0034] In this case, the mixer has an l-shaped layout wherein the first container and the second container are moved relative to the corresponding mixing heads along aligned and opposite directions, that is to say, laterally. In an alternative embodiment, the first guide and the second guide may be perpendicular to each other.

[0035] In this case, the mixer has an L-shaped layout wherein the first mixing head and the second mixing head are accessible along respective directions at right angles to each other. In other words, access is made to one mixing head at the front and to the other mixing head at the side.

[0036] In an embodiment, the first guide and the second guide are parallel to each other.

[0037] In this case, the mixer has a U-shaped layout wherein the access to both the mixing heads is frontal.

[0038] More generally speaking, the first guide and the second guide may be positioned according to respective orientations selected freely, even not parallel or not perpendicular to each other, depending on the space available in the location in which the mixer is installed.

[0039] In an embodiment, each mixing head can be moved relative to the supporting structure between a lowered position in which accessory operations can be performed on the mixing head and a raised position for mixing the ingredients.

[0040] In an embodiment, a mixing head selected between the first mixing head and the second mixing head is configured to be positioned in the raised position whilst the other mixing head selected between the second mixing head and the first mixing head is in the lowered position.

[0041] In an embodiment, each mixing head can be inclined about a positioning axis, which may be horizontal, between a loading / unloading orientation wherein the respective container has an opening facing upwards and a mixing orientation wherein the respective container is overturned.

[0042] The mixing head may also be positioned in a plurality of intermediate orientations interposed between the loading / unloading orientation and the mixing orientation.

[0043] The numerous possibilities of movement of the mixing head allow easy access to the mixing head for cleaning and maintenance operations. In particular, the cleaning and maintenance operations may be performed whilst the mixing head is positioned in the lowered position and with an inclined orientation which is easily accessible by the operator.

[0044] This avoids the use of ladders and increases the safety of the operator, even in the case of large mixers.

[0045] In an embodiment, a mixing head selected between the first mixing head and the second mixing head can be positioned in an orientation about the positioning axis different from the orientation about the positioning axis wherein the other mixing head selected between the second mixing head and the first mixing head is at that instant.

[0046] For example, a mixing head selected between the first mixing head and the second mixing head may be configured to be positioned in the mixing orientation, whilst the other mixing head selected between the second mixing head and the first mixing head is positioned in the loading / unloading orientation.

[0047] In an embodiment, a mixing head selected between the first mixing head and the second mixing head may be configured to be positioned in the mixing orientation, whilst the other mixing head selected between the second mixing head and the first mixing head is positioned in an intermediate orientation between the loading / unloading orientation and the mixing orientation, to be subjected to maintenance, setting or cleaning operations.

[0048] In an embodiment, each mixing head has a plurality of gripping elements for engaging with an edge of the respective container and locking the container against the mixing head.

[0049] It is in this way possible to make the container integral with the mixing head during a mixing step.

[0050] In a second aspect of the invention, there is provided a method for mixing flowable substances in a mixer comprising at least one mixing head having a mixing tool, the method comprising the steps of: positioning a container containing the flowable substances below the mixing head, the container being positioned in a loading / unloading orientation wherein a cavity of the container is open upwards; coupling the container to the mixing head in an engagement position of the mixing head; raising the mixing head coupled to the container from the engagement position to a raised position; lowering the mixing head coupled to the container from the raised position to an operating position in which the mixing tool mixes the flowable substances contained in the container to obtain a mixture, wherein, in the operating position, the mixing head coupled to the container is positioned in a mixing orientation wherein the container is substantially overturned.

[0051] Owing to the second aspect of the invention, it is possible to effectively mix two or more ingredients to obtain a mixture.

[0052] By lowering the mixing head coupled to the container from the raised position to the working position, it is possible to keep at a not excessive height the assembly comprising the mixing head coupled to the container, which increases the stability of the mixer and limits the mechanical stresses.

[0053] The invention can be better understood and implemented with reference to the accompanying drawings which illustrate a non-limiting example embodiment of it and wherein:

[0054] Figure 1 is a perspective view showing a mixer for mixing flowable substances;

[0055] Figure 2 is a perspective view of the mixer of Figure 1 , in a different operating configuration;

[0056] Figure 3 is a side view of the mixing device of Figure 2;

[0057] Figure 4 is a plan view of a mixer such as that of Figure 1 , configured according to an L-shaped layout; Figure 5 is a plan view of a mixer such as that of Figure 1 , configured according to an l-shaped layout;

[0058] Figure 6 is a plan view of a mixer such as that of Figure 1 , configured according to a U-shaped layout;

[0059] Figures 7 to 10 are schematic side views showing a gripping element of the mixer of Figure 1 , in successive operating positions;

[0060] Figures 11 to 16 are schematic views showing a container of the mixer of Figure 1 , in successive operating positions.

[0061] Figure 1 shows a mixer 1 for mixing flowable substances in such a way as to obtain mixtures. The flowable substances which are mixed in the mixer 1 may be liquid substances, for example solvents or water, or substances in a powder or granular state, or substances in a pasty state. The mixer 1 may be in particular used for preparing paints, but also for preparing other mixtures.

[0062] The mixer 1 comprises a supporting structure 2, which in the example shown comprises a box-shaped body 3. The box-shaped body 3 may have a substantially parallelepiped shape. According to the example shown, the box-shaped body 3 is delimited by a front wall 4, by a rear wall 5 opposite the front wall 4 and by two side walls 6 interposed between the front wall 4 and the rear wall 5. The front wall 4, the rear wall 5 and the side walls 6 are substantially vertical.

[0063] The box-shaped body 3 may also have shapes different from the parallelepiped shape.

[0064] For example, the supporting structure 2 may comprise a body 3 having a cylindrical shape.

[0065] The mixer 1 also comprises a first mixing head 11 and a second mixing head 12, supported by the supporting structure 2. In particular, the first mixing head 11 and the second mixing head 12 may be supported by respective opposite walls which delimit the supporting structure 2. More specifically, the first mixing head 11 and the second mixing head 12 may be located at respective opposite side walls 6 of the supporting structure 2.

[0066] By positioning the mixing heads 11 , 12 on opposite walls of the supporting structure 2, it is possible to easily obtain a distribution of balanced masses so that the mixer 1 does not need supports outside the box-shaped body 3.

[0067] It is, however, also possible to position the mixing heads 11 , 12 at walls which are not opposite each other.

[0068] It is also possible to position the mixing heads 11 , 12 on separate portions of a same wall of the box-shaped body 3.

[0069] The supporting structure 2 houses a control unit having the purpose of controlling the operation of the first mixing head 11 and the second mixing head 12, as described in more detail below.

[0070] The first mixing head 11 and the second mixing head 12 therefore share a common supporting structure, that is to say, the supporting structure 2, and a common control unit.

[0071] A control panel 8 may be provided on the front wall 4 to allow an operator to control and modify the operating modes of the mixing heads 11 and 12. The mixing heads 11 , 12 have a structure similar to each other.

[0072] Each mixing head 11 , 12 comprises a body 13 delimited by a closing face 14 on which there is a mixing tool 15, shown in Figures 2 and 3.

[0073] According to the example shown, the closing face 14 is substantially flat, which makes the closing face 14 easy to clean. In an alternative embodiment, the closing face 14 may have a geometry which is not flat. For example, the closing face 14 may have a concave geometry. The concave geometry defines a space in which a chopping tool may be received in addition to the mixing tool 15, or one or more sensors, or other elements.

[0074] The mixing tool 15 may comprise a shaft 16 rotatable about an axis of rotation R. A plurality of blades 17 project from the shaft 16. According to the example shown there are four blades 17, that is to say, a pair of blades furthest from the closing face 14, which are longer and have a flat shape, and a pair of blades furthest from the closing face 14, which are shorter and may not be flat.

[0075] However, the shape and the number of blades 17 may be chosen arbitrarily, depending on the type of mixture to be obtained and on the ingredients selected.

[0076] Each mixing head 11 , 12 also comprises a motor 18 for rotating the corresponding mixing tool 15 about the axis of rotation R. The motor 18 may be supported by a rear face 19 of the body 13. The rear face 19 is opposite the closing face 14.

[0077] The mechanisms are housed inside the body 13 which allow the motor 18 to transmit the rotational movement about the axis R to the mixing tool 15. The mixer 1 also comprises a first container 21 for producing a first mixture by mixing a plurality of ingredients in the form of flowable substances. The first container 21 can be coupled to the first mixing head 11 , the mixing tool of which is designed to mix the ingredients introduced into the first container 21 .

[0078] There is also a second container 22 which can be coupled to the second mixing head 12 for producing a second mixture by mixing a plurality of ingredients in the form of flowable substances.

[0079] The first container 21 and the second container 22 have a similar structure and each comprise a containment body 20 in which a cavity is formed for receiving the ingredients of the mixture to be produced. Each container 21 , 22 also comprises an edge portion 23 which projects outwards from an open end of the containment body 20. When the container 21 , 22 is positioned in such a way that its cavity faces upwards, the edge portion 23 is positioned at an upper end of the container 21 , 22.

[0080] According to the example shown, the edge portion 23 is shaped like a flange, in particular a flat flange, for example in the form of a circular crown, even though this condition is not necessary and other geometrical shapes are possible. For example, instead of being shaped like a continuous flange, the edge portion 23 could comprise a plurality of separate protruding elements, which project outwards from the open end of the containment body 20.

[0081] Each container 21 , 22 is movable towards, and away from, the corresponding mixing head 11 , 12 in such a way as to be moved to engage with the corresponding mixing tool or alternatively move away from the latter.

[0082] In order to be moved more easily, each container 21 , 22 may be provided with wheels 24.

[0083] There is also a first guide 31 along which the first container 21 can slide for being moved towards the first mixing head 11 or moved away from the latter.

[0084] A second guide 32 is positioned to guide the second container 22 whilst the latter is moved towards, or away from, the second mixing head 12.

[0085] The first guide 31 and the second guide 32 may be linear guides. The first guide 31 and the second guide 32 may comprise respective guide tracks designed to be fixed to the floor of the room in which the mixer 1 is housed.

[0086] The first guide 31 may extend along a first direction of movement S1 , whilst the second guide 32 may extend along a second direction of movement S2.

[0087] The first container 21 and the second container 22 may comprise respective guide elements 27 designed to engage, respectively, in the first guide 31 and in the second guide 32 for being guided along the corresponding directions of movement S1 , S2. The guide elements 27 may protrude from a bottom portion of the first container 21 and, respectively, of the second container 22.

[0088] On the closing face 14 of each mixing head 11 , 12 there may be a plurality of gripping elements 28, designed to engage with the corresponding container 21 , 22 to bring the container 21 , 22 into contact with the closing face 14 and clamp the container 21 , 22 against the closing face 14. In this way, the gripping elements 28 allow the container 21 , 22 to be locked in contact with the respective closing face 14, thus making the container 21 , 22 fixed relative to the respective mixing head 11 , 12.

[0089] According to the example shown, there are four gripping elements 28 on the closing face 14 of each mixing head 11 , 12, the operation of which is described in detail below.

[0090] In an alternative embodiment, there may be a number of gripping elements different from four. Gripping elements may also have a structure different from that shown in the drawings. For example, a single gripping element, shaped like a half-moon or a half-circle, might be sufficient.

[0091] Each mixing head 11 , 12 is fixed to a support 29 which is mounted on a rotary element 30 included in the supporting structure 2. The rotary element 30 can rotate about a positioning axis H, which in the example shown is horizontal.

[0092] In this way, each mixing head 11 , 12 may be rotated about the positioning axis H for positioning it in a plurality of orientations different from each other. In particular, each mixing head 11 , 12 may be positioned in a loading / unloading orientation 01 , shown in the left-hand part of Figure 1 , and in a mixing orientation 02, shown in the right-hand part of Figure 1 .

[0093] In the loading / unloading orientation 01 , the cavity of the containment body 20 is open upwards and it is possible to load the container 21 , 22, filled with the desired ingredients, on the mixer 1. In the mixing orientation 02, the container 21 , 22 is overturned, in particular rotated by approximately 180° relative to the loading / unloading orientation 01.

[0094] In the mixing orientation 02, the cavity of the containment body 20 has an open end facing downwards. The open end is closed by the closing face 14 of the mixing head 11 , 12, which prevents escape of the substances to be mixed. These substances flow downwards due to the force of gravity, surrounding the mixing tool 15, which is thus completely immersed in the substances to be mixed. By rotating about the positioning axis H, each mixing head 11 , 12 may also be positioned in a plurality of intermediate orientations interposed between the loading / unloading orientation 01 and the mixing orientation 02. One of these intermediate orientations, labelled Oi, is shown in the left-hand part of Figure 2 and in Figure 3. In the orientation Oi, the mixing tool 15 is facing upwards, whilst the closing face 14 lies approximately on a plane slightly inclined relative to the horizontal direction, for example inclined at an angle of less than 30° relative to the horizontal direction.

[0095] The container 21 , 22 has been removed. By positioning the mixing head 11 , 12 in the intermediate orientation Oi, it is possible to easily perform cleaning or maintenance operations on the mixing head 15, as described in more detail below.

[0096] The rotary element 30 is supported by a supporting plate 33, which is slidable relative to the box-shaped body 3 along a sliding direction Y, which in the example shown is vertical.

[0097] The supporting plate 33 is moved by an actuator device housed in the box-shaped body 3.

[0098] The mixing head 11 , 12 may thus be raised or lowered, moving it vertically as described in more detail below.

[0099] The first container 21 and the second container 22 may also be fixed to the supporting structure 2 by a fixing system different from that shown; For example, the first container 21 and the second container 22 could be supported by the respective side walls 6 by means of respective arms.

[0100] During operation, a container selected between the first container 21 and the second container 22, for example the first container 21 , having inside it the ingredients for producing the desired mixture, is moved along the relative direction of movement, that is to say, the first direction of movement S1 , to be carried beneath the corresponding mixing head, that is to say, the first mixing head 11. The first container 21 may be moved manually by the operator. The first container 21 is thus positioned in a position vertically aligned with the first mixing head 11 and beneath the latter.

[0101] The first mixing head 11 , previously positioned in the loading / unloading orientation 01 wherein the mixing tool 15 is facing downwards, is positioned vertically, along the sliding direction Y, in an initial position P1 shown in Figure 11. In the initial position P1 , the first mixing head 11 is vertically spaced from the first container 21 , in such a way that the gripping elements 28, although close to the first container 21 , are vertically separated from the latter.

[0102] In the initial position P1 , the first mixing head 11 is positioned at a height Z1.

[0103] The first mixing head 11 is now lowered, moving it along the sliding direction Y, until the closing face 14 is moved a short distance from the first container 21 , in particular from the edge portion 23 of the first container 21. In this way, an engagement position P2 is reached, shown in Figure 12, in which the gripping elements 28 are close to the edge portion 23 and can engage with the first container 21. The first mixing head 11 is now positioned at a height Z2, less than the height Z1 at which the first mixing head 11 was in the initial position P1 .

[0104] The positioning of the gripping elements 28 and of the first container 21 during this step is shown in detail in Figure 7. Figure 7 schematically shows a portion of the first container 21 and a portion of the closing face 14 of the first mixing head 11. What is described below with reference to the first mixing head 11 is also applicable to the second mixing head 12.

[0105] As already mentioned, on the closing face 14 there is a plurality of gripping elements 28, designed to be positioned along the edge portion 23 of the first container 21 , only one of which is shown in Figure 7. Each gripping element 28 comprises a fixed part 34, which is fixed relative to the closing face 14, and a movable part 35, which is movable relative to the fixed part 34. In the example shown, the movable part 35 can be moved with a roto- translation movement relative to the fixed part 34, but this condition is not necessary.

[0106] There is also an actuator 36, which may be, for example, hydraulic, pneumatic or electric, comprising a cylinder 37 fixed relative to the closing face 14. The cylinder 37 and the fixed part 34 are located on opposite sides of the closing face 14, so that the closing face 14 is interposed between the cylinder 37 and the fixed part 34.

[0107] The actuator 36 also has a rod, not illustrated. A hinge pin 38 is fixed relative to the rod of the actuator 36 and projects transversely relative to the rod. The movable part 35 is hinged to the rod at the hinge pin 38. In other words, the movable part 35 is rotatable about the hinge pin 38, which in turn is movable in a linear fashion parallel to the sliding direction Y.

[0108] The trajectory of the movable part 35 is controlled by a cam controller, comprising, for example, a cam track 39 made on the movable part 35. The cam track 39 may have the shape of a slot passing through the thickness of the movable part 35. The cam track 39 may have a first stretch 40, a second stretch 41 and an intermediate stretch 42 interposed between the first stretch 40 and the second stretch 41 . The first stretch 40 and the second stretch 41 may be rectilinear, for example parallel to each other. The intermediate stretch 42 may also be rectilinear.

[0109] The cam controller also comprises a constraining pin or cam follower 43 which may be shaped like a roller supported by the fixed part 34. The constraining pin 43 engages in the cam track 39, in such a way that the movable part 35 moves according to a predetermined law.

[0110] The movable part 35 is delimited by a contact surface 44 designed to come into contact with the edge portion 23 of the first container 21 .

[0111] Figure 7 shows an initial step in which the rod of the actuator 36 is located in an extended position, that is to say, it protrudes from the cylinder 37 for a maximum length. The hinge point 38 is at its minimum height and the cam follower 43 is positioned at the start of the first rectilinear stretch 40. The movable part 35 is in a maximum open configuration in which it is disengaged from the first container 21 and far from the edge portion 23.

[0112] As already mentioned above, the first container 21 is below the first mixing head 11 , which is positioned in the loading / unloading orientation 01 in such a way that the mixing tool 15 is facing towards the cavity of the first container 21. The closing face 14 is at a distance D from the edge portion 23.

[0113] At this point, the rod of the actuator 36 is retracted, so as to make it reenter at least partly inside the cylinder 37. The hinge pin 38 is consequently moved upwards. The constraining pin 43, which is located in a fixed position, continues to be engaged in the cam track 39 and rotates the movable part 45 about the hinge pin 38. The contact surface 44 consequently moves towards the edge portion 23, whilst remaining still spaced from the latter.

[0114] In the instant shown in Figure 8, the constraining pin 43 is positioned along the intermediate stretch 42 of the cam track 39.

[0115] Continuing to withdraw the rod inside the cylinder 37, the hinge pin 38 is moved upwards and the movable part 35 is rotated about the hinge pin 38, so that the constraining pin 43 is disengaged from the intermediate stretch 42 and is positioned at the start of the second rectilinear stretch 41 . The contact surface 44 is now parallel to the edge portion 23, that is to say, it lies on a horizontal plane. The contact surface 44 is still spaced from the edge portion 23, which in turn is spaced from the closing face 14.

[0116] The second stretch 41 of the cam track 39 is now positioned parallel to the sliding direction Y, that is to say, it is vertical, as shown in Figure 9.

[0117] The rod of the actuator 36 is further moved towards the inside of the cylinder 37. The movable part 35 moves upwards moving with linear motion, without rotating. A relative translation movement occurs between the constraining pin 43 and the cam track 39, in particular the second rectilinear stretch 41 of the latter. The contact surface 44 of the movable part 35 comes into contact with a lower surface of the edge portion 23 and raises the first container 21 , bringing the edge portion 23 into contact with the closing face 14, in particular at an upper surface of the edge portion 23, as shown in Figure 10. This situation is also shown schematically in Figure 13, from which it should be noted that the first mixing head 11 is still in the engagement position P2. The movement of the movable part 35 by which the movable part 35 makes contact against the edge portion 23 and the first container 21 is raised to be brought into contact with the closing face 14 therefore occurs whilst the first mixing head 11 is vertically stationary at the height Z2.

[0118] The first container 21 is now engaged with the first mixing head 11. The gripping elements 28 lock the first container 21 in contact with the closing face 14 of the first mixing head 11. The closing face 14 closes the first container 21 , preventing the substances present inside it from escaping.

[0119] At this point, the first mixing head 11 may be moved upwards along the sliding direction Y until reaching a raised position P3, shown in Figure 14. In this way, the first container 21 , which is now fixed relative to the first mixing head 11 , is also moved to the raised position P3 and the guide element 27 is disengaged from the first guide 31 . The first mixing head 11 is now at a height Z3, greater than the height Z2. The first mixing head 11 is still in the loading / unloading orientation 01 , that is to say, the open end of the first container 21 , closed by the closing face 14, faces upwards.

[0120] In the raised position P3, the first mixing head 11 may be rotated about the positioning axis H to be positioned in the mixing orientation 02, wherein the first container 21 is overturned, as shown in Figure 15.

[0121] At this point, the first mixing head 11 may be lowered until reaching a working position P4, shown in Figure 16. In the operating position P4, the first mixing head 11 , which is positioned in the mixing orientation 02, is at a height Z4 less than the height Z3. This allows the height of the barycentre to be lowered of the assembly formed by the first mixing head 11 and the first container 21 .

[0122] The mixing tool 15 is rotated about the axis of rotation R, so as to start the mixing step wherein the ingredients present in the first container 21 are mixed to form the first mixture.

[0123] The first mixing head 11 is maintained in the orientation of mixing 02 for the entire duration of the mixing step.

[0124] When the ingredients present in the first container 21 have been mixed and the respective mixture has been obtained, the mixing tool 15 stops rotating and the sequence of operations described with reference to Figures 11 to 16 is performed in the reverse order to disengage the first container 21 from the first mixing head 11 and move it away from the latter.

[0125] In an alternative embodiment not illustrated, the ingredients present in the first container 21 can be mixed whilst the first container 21 is in the raised position P3 and is positioned in the mixing orientation 02. In this embodiment, the first mixing head 11 is not lowered until reaching the height Z4 after being overturned, because the mixing step occurs when the first mixing head 11 is still at the height Z3.

[0126] The working position P4 is not reached in this case.

[0127] In an alternative embodiment not illustrated, the first container 21 may be brought below the first mixing head 11 , moving it along the first direction of movement S1 , whilst it is at a height at which the first container 21 is already ready to engage with the gripping elements 28. Lowering the first mixing head 11 from the initial position P1 to the engagement position P2 may therefore be, in certain embodiments, unnecessary.

[0128] The first mixing head 11 could be configured to move vertically the first container 21 only between two positions, for example the engagement position P2 and the raised position P3.

[0129] In an alternative embodiment, the first mixing head 11 , initially positioned in the loading / unloading orientation 01 , may be moved from the raised position P3 to the working position P4 after having been rotated about the positioning axis H by an initial angle of less than 90°, for example between 15° and 25° (sufficient to prevent interference between the ground and the wheels 24 during rotation).

[0130] The first mixing head 11 may therefore be moved downwards along the direction of movement Y, before ending the rotation about the positioning axis H to reach the mixing orientation 02. This allows the barycentre of the first mixing head 11 to be kept at a relatively low height during the rotation about the positioning axis H.

[0131] Alternatively, the first mixing head 11 may be lowered from the raised position P3 to the working position P4, to keep limited the height of the respective barycentre, after the mixing orientation 02 has been reached.

[0132] After having moved the first container 21 away from the first mixing head 11 , the first container 21 may be carried into working units, not illustrated, of the plant, or stored waiting to be subjected to subsequent processing. A new first container 21 , containing the ingredients for a new mixture, may be carried to engage with the first mixing head 11 .

[0133] The second mixing head 12 operates in a similar manner to that described above with reference to the first mixing head 11 .

[0134] The first mixing head 11 and the second mixing head 12 may be, at the same instant, in different operating conditions.

[0135] For example, whilst the first mixing head 11 is positioned in the loading / unloading orientation 01 , as shown in the left-hand part of Figure 1 , the second mixing head 21 may be positioned in the mixing orientation 02, as shown in the right-hand part of Figure 1 . This allows the operator to remove the first container 21 from the first mixing head 11 and position a new first container 21 below the first mixing head 11 , whilst the mixing step is occurring in the second container 22.

[0136] When the first container 21 has been coupled to the first mixing head 11 , the operator can dedicate him / herself to removing the second container 22 from the second mixing head 12 and therefore carrying to the second mixing head 12 a new second container 22 filled with new ingredients.

[0137] It is that is to say, it is possible to alternate the steps of mixing in the first container 21 and in the second container 22 in such a way that, whilst the ingredients are mixed in one of the two containers automatically, the operator can work on the other container for unloading it and replacing it with another container containing new ingredients to be mixed.

[0138] This allows the downtime for the operator to be reduced and increases the productivity of the mixer 1 .

[0139] Moreover, when a mixing head is disengaged from the relative container, it is possible to easily perform cleaning, maintenance and / or setting operations on the mixing head.

[0140] For example, Figures 2 and 3 show the first mixing head 11 from which the first container 21 has been removed. The first mixing head 11 may be positioned at a relatively low height and rotated about the positioning axis H to position it in an intermediate orientation Oi, wherein the contact face 14 is facing almost upwards and inclined towards the operator.

[0141] By positioning the mixing head at a relatively low height, the operator can access the mixing tool 15 without using ladders, stools or similar aids which could result in a danger of falling. Moreover, by rotating the mixing head in the intermediate orientation Oi, the operator can work on the mixing tool 15 without the need to bend excessively or keep arms raised for long periods of time, which increases the comfort for the operator and reduces the risks linked to a cleaning or setting performed at a relatively great height.

[0142] Whilst maintenance, setting or cleaning operations are performed on the first mixing head 11 , the second mixing head 12 may continue to work regularly, as shown in the right-hand side of Figure 2, wherein the second mixing head 12 is positioned in the mixing orientation 02.

[0143] Even if the mixer 1 is used in an optimum manner, from the point of view of productivity, when one of the two mixing heads is in a mixing step whilst the operator acts on the other mixing head to remove a container and load a new container, the mixer 1 may also operate according to different modes. For example, both the mixing heads 11 , 12 might be simultaneously in a mixing step, if there is the need.

[0144] The mixer 1 is therefore particularly adaptable to the production requirements.

[0145] The operation of the first mixing head 11 and the second mixing head 12 is controlled by a shared control unit, housed in the box-shaped body 3 and supported by the supporting structure 2. The control unit controls the operation of both the mixing heads, in particular activating and deactivating the mechanisms which raise or lower the mixing heads along the sliding direction Y, and / or the mechanisms which rotate the mixing heads about the positioning axis H, and / or actuating or stopping the motors 18, and / or acting on the actuators 36.

[0146] By using a single control unit, it is possible to avoid the duplication of the components which control the mixing heads, in particular avoid the duplication of electronic components. It is also possible to provide operating and safety logics coordinated between the first mixing head 11 and the second mixing head 12.

[0147] Moreover, by using a common supporting structure 2 which supports both the first mixing head 11 and the second mixing head 12, and a common control unit which controls both the first mixing head 11 and the second mixing head 12, it is possible to reduce the costs and overall dimensions of the mixer 1 compared with the case in which two mixers of known type are used, each of which has a single mixing head.

[0148] The mixer 1 is also particularly adaptable to the space available at the factory in which it is installed, since the layout of the machine in which the mixer 1 is incorporated can be adapted to the space available in the building in which the machine is positioned.

[0149] More specifically, the first direction of movement S1 along which the first container 21 can be moved to be engaged with the first mixing head 11 or to be disengaged from the latter can be chosen arbitrarily. The second direction of movement S2 along which the second container 22 can be moved to be carried beneath the second mixing head 12 or moved away from the latter can also be freely selected.

[0150] For example, Figure 4 illustrates a layout of the mixer 1 which, in a plan view, has the “L” shape, similar to that shown in Figure 1 .

[0151] In the example shown in Figure 4, the first direction of movement S1 is perpendicular to the second direction of movement S2. More specifically, the first container 21 is brought to engage with the first mixing head 11 at the front, that is to say, moving it along a direction of movement S1 substantially perpendicular to the front wall 4 of the box-shaped body 3. The second container 22, on the other hand, is moved to engage with the second mixing head 12 laterally, that is to say, moving it along a direction of movement S2 substantially perpendicular to the side wall 6 on which the second mixing head 12 is mounted.

[0152] In the embodiment shown in Figure 5, the first mixing head 11 and the second mixing head 12 may be fed with the respective containers according to an l-shaped layout. The first direction of movement S1 and the second direction of movement S2 are in effect parallel to each other, in particular aligned. In other words, the first container 21 and the second container 22 are moved along equal and different directions to be made to engage with the first mixing head 11 and, respectively, with the second mixing head 12.

[0153] Both the containers 21 , 22 are, therefore, made to engage with the respective mixing heads 11 , 12 laterally, that is to say, along directions of movement S1 and S2 perpendicular to the respective side faces 6.

[0154] In the embodiment shown in Figure 6, on the other hand, there is a U- shaped layout of the mixer 1 , wherein the containers 21 , 22 are made to engage with the respective mixing heads 11 , 12 at the front, that is to say, along respective directions of movement S1 , S2 perpendicular to the front wall 4. The layouts shown in Figures 4 to 6, or other layouts not illustrated, may be selected freely depending on the space available for moving the containers 21 , 22 in the factory in which the mixer 1 is installed. The layout may also be modified during the life of the mixer 1 , if necessary.

[0155] In order to adopt a particular type of layout, it is sufficient to position the guides 31 , 32 along the corresponding directions of movement S1 , S2.

[0156] The mixer 1 may be used for producing, in the first container 21 , a first mixture different from the second mixture produced in the second container 22, or equal to the latter. The mixer 1 is very versatile also in terms of the substances which can be mixed.

[0157] For example, in the case of paints, the first container 21 may be used to produce paints of a light colour, whilst the second container 22 may be used to produce paints of a dark colour. This simplifies the cleaning of the mixer 1 , because in order to change from a light coloured paint to a paint of another light colour (or from a dark coloured paint to a paint of another dark colour) it is sufficient to clean less accurately than what would be necessary if changing from a light coloured paint to a dark coloured paint, or vice versa.

[0158] In an alternative embodiment not illustrated, the gripping elements 28 can also be used in combination with a mixer which comprises a single mixing head.

[0159] Even though the drawings show a mixer 1 comprising two mixing heads, it is possible to provide a mixer having three or more mixing heads, supported by the same supporting structure and controlled by a shared control unit.

[0160] According to the examples described above, the mixing orientation 02 was reached by rotating the mixing head by 180° about the positioning axis H, in such a way that the axis of rotation R of the mixing tool 15 was vertical during the mixing step.

[0161] In an alternative embodiment, the mixing tool 15 could start to mix the substances present in the relative container even before the mixing orientation 02 is reached, that is to say, also whilst the axis of rotation R is still inclined relative to the vertical direction.

[0162] In a further alternative embodiment, the mixing orientation 02 may be reached by rotating the mixing head by an angle different from 180° about the positioning axis H, for example by rotating the mixing head by an angle of between 140° and 220° about the positioning axis H.

[0163] In this case, the mixing tool 15 mixes the substances present in the respective container rotating about an axis of rotation R inclined relative to the vertical direction.

Claims

CLAIMS1. A mixer for preparing mixtures by mixing flowable substances, comprising a control unit, a supporting structure (2), a first mixing head(11 ) which can be coupled to a first container (21 ) for preparing a first mixture, a second mixing head (12) which can be coupled to a second container (22) for preparing a second mixture, wherein the first mixing head (11) and the second mixing head (12) are both supported by the supporting structure (2) and are connected to the control unit, so that the control unit controls both the first mixing head (11 ) and the second mixing head (12), and wherein the first mixing head (11 ) and the second mixing head (12) are configured to be positioned in different operating conditions at the same instant.

2. The mixer according to claim 1 , wherein at least one mixing head selected between the first mixing head (11 ) and the second mixing head(12) is rotatable about a positioning axis (H) between a loading / unloading orientation (01 ) in which the respective container selected between the first container (21) and the second container (22) has an open end facing upwards and a mixing orientation (02) in which the respective container is substantially overturned.

3. The mixer according to claim 2, wherein a mixing head selected between the first mixing head (11 ) and the second mixing head (12) is positionable in an orientation about the positioning axis (H) different from the orientation about the positioning axis (H) in which the other mixing head selected between the second mixing head (12) and the first mixing head (11 ) is at that instant.

4. The mixer according to claim 2 or 3, wherein said at least one mixing head is positionable at least in an intermediate orientation (Oi) interposed between the loading / unloading orientation (01) and the mixing orientation(02) to allow an operator to perform cleaning and / or maintenance and / or setting operations.

5. The mixer according to any one of claims 2 to 4, wherein said at least one mixing head is supported by a rotatable element (30) which can rotate about the positioning axis (H), the rotatable element (30) being mounted on a vertically slidable supporting plate (33).

6. The mixer according to any preceding claim, wherein at least one mixing head selected between the first mixing head (11) and the second mixing head (12) is vertically movable relative to the supporting structure(2) between a lowered position (P1 ; P2) in which a container selected between the first container (21 ) and the second container (22) is ready to engage with the corresponding mixing head and a raised position (P3; P4) for mixing the flowable substances contained in said container.

7. The mixer according to claim 6, wherein a mixing head selected between the first mixing head (11 ) and the second mixing head (12) is positionable relative to the supporting structure (2) at a height different from the height at which the other mixing head selected between the second mixing head (12) and the first mixing head (11) is at that instant.

8. The mixer according to any preceding claim, wherein the supporting structure (2) comprises a body (3) which houses the control unit, the body(3) being delimited by at least one side wall (6), the first mixing head (11 ) and the second mixing head (12) being provided on two distinct portions of said at least one side wall (6).

9. The mixer according to claim 8, wherein the body (3) is a box-shaped body having a substantially parallelepiped shape, the first mixing head (11)and the second mixing head (12) being provided on two opposite side walls (6) of the box-shaped body.

10. The mixer according to any preceding claim, wherein at least one mixing head selected between the first mixing head (11) and the second mixing head (12) is delimited by a closing face (14) suitable for engaging with a respective container selected between the first container (21) and the second container (22) for closing the respective container.

11. The mixer according to claim 10, wherein at least one mixing head selected between the first mixing head (11 ) and the second mixing head (12) comprises a mixing tool (15) which is provided on the closing face (14) and is rotatable about an axis of rotation (R) for mixing the contents of the first container (21) or, respectively, of the second container (22).

12. The mixer according to any preceding claim, wherein a first guide (31) is provided for guiding the first container (21) along a first direction of movement (S1) towards, or away from, the first mixing head (11 ), and wherein a second guide (32) is provided for guiding the second container (22) along a second direction of movement (S2) towards, or away from, the second mixing head (12), the first guide (31) and the second guide (32) being positionable according to a desired layout so as to select the first direction of movement (S1) and the second direction of movement (S2) depending on the space available around the mixer (1 ).

13. The mixer according to any preceding claim, wherein at least one mixing head selected between the first mixing head (11) and the second mixing head (12) has at least one gripping element (28) for engaging with an edge portion (23) of a respective container selected between the first container (21 ) and the second container (22) and locking the container against the mixing head.

14. The mixer according to claim 13, wherein the at least one gripping element (28) comprises a fixed part (34) which is fixed relative to the mixing head and a movable part (35) which is movable along a trajectory, said trajectory comprising a first stretch in which a contact surface (44) of the movable part (35) is arranged parallel to the edge portion (23) and a second stretch in which the movable part (35) is linearly moved, optionally vertically, for bringing the contact surface (44) in contact with the edge portion (23) and raising the container thereby bringing it into contact with the corresponding mixing head.

15. The mixer according to claim 14, wherein the movable part (35) is operable by an actuator (36) along said trajectory and is controlled by a cam controller.

16. The mixer according to claim 15, wherein the actuator (36) has a rod which is fixed relative to a hinge pin (38) about which the movable part (35) is rotatable, the rod being movable in a sliding direction (Y) transversely relative to the edge portion (23) of the container.

17. The mixer according to claim 15 or 16, wherein the cam controller comprises a cam track (39) having a portion (40, 42) for modifying an angle between the fixed part (34) and the movable part (35) and a further portion (41 ) for moving the movable part (35) towards the edge portion (23) of the container along said second stretch, so that the movable part (35) blocks the edge portion (23) of the container, thereby making the container fixed relative to the mixing head (15), and wherein optionally the cam track (39) is a through slot made on the movable part (35), a constraining pin (43) fixed relative to the fixed part (34) engaging in the cam track (39).

18. A method for mixing flowable substances in a mixer (1 ) comprising at least one mixing head (11 , 12) having a mixing tool (15), the method comprising the steps of: positioning a container (21 , 22) containing the flowable substances below the mixing head (11 , 12), the container being arranged in a loading / unloading orientation (01 ) in which a cavity of the container (21 , 22) faces upwards; coupling the container (21 , 22) to the mixing head (11 , 12) in an engagement position (P2) for engaging the mixing head (11 , 12); raising the mixing head (11 , 12) coupled to the container (21 , 22) from the engagement position (P2) to a raised position (P3); lowering the mixing head (11 , 12) coupled to the container (21 , 22) from the raised position (P3) to an operating position (P4) in which the mixing tool (15) mixes the flowable substances contained in the container (21 , 22) to obtain a mixture, wherein, in the operating position (P4), the mixing head (11 , 12) coupled to the container (21 , 22) is arranged in a mixing orientation (02) in which the container (11 , 12) is substantially overturned.

19. The method according to claim 18, wherein the mixing head (11 , 12) coupled with the container (21 , 22) is rotated from the loading / unloading orientation (01) to the mixing orientation (02) whilst the mixing head (11 , 12) is in the raised position (P3).

20. The method according to claim 18, wherein the rotation of the mixing head (11 , 12) coupled with the container (21 , 22) for carrying the mixing head (11 , 12) from the loading / unloading orientation (01) to the mixing orientation (02) starts whilst the mixing head (11 , 12) is in the raised position (P3) and continues whilst the mixing head (11 , 12) is lowered towards the operating position (P4).21 . The method according to any one of claims 18 to 20, wherein, after the container (21 , 22) has been positioned below the mixing head (11 , 12), the mixing head (11 , 12) is lowered from an initial position (P1) to the engagement position (P2) to bring at least one gripping element (28) supported by the mixing head (11 , 12) to engage with the container (21 , 22), so as to make the container (21 , 22) fixed relative to the mixing head (11 , 12).

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