ITPG20130016A1 - MIXER WITH HORIZONTAL AXIS - Google Patents

Description

Description of the invention having as title:

"MIXER WITH HORIZONTAL AXES"

FIELD OF APPLICATION

The present invention relates to a mixer with horizontal axes for concrete, mortar, powders, dry and semi-dry granulates, cement-based mixtures or similar or similar mixtures or mixes.

STATE OF THE TECHNIQUE

In construction, for some time now, mixers for concrete, mortar, powders, dry and semi-dry granulates and similar conglomerate materials have been widely used, in order to prepare large volumes of these conglomerates, preferably destined to be loaded on the truck-mounted concrete mixers, to be then thrown . Examples of mixers are described in European patent applications EP-A-1.685.933, EP-A-2. 146.795 and EP-A-2.146.796 in the name of the Applicant.

Horizontal and vertical axis mixers are known. In particular, the traditional horizontal axis mixers used comprise a mixing tank within which one or more rotating transverse shafts, usually parallel and counter-rotating, operate, intended for mixing the mixtures loaded into the aforementioned tank.

Each of these revolving transverse shafts supports a series of radial arms used to support respective mixing blades, which, during the rotation of the respective shafts, are able to effectively interfere with the mixture to be amalgamated, repeatedly stirring and mixing conveniently. the components of the mixture loaded into the aforementioned tank.

In correspondence with the transversal sides of the tank there are seats in which to insert the mixing shafts, with the interposition of suitable bearings and sealing gaskets.

On the outside of one or both of these transverse sides, on the other hand, drive units are mounted which are designed to drive each of the same mixing shafts in rotation.

Such a drive unit is equipped with an electric motor which drives, directly or by means of a transmission belt, a planetary gear motor, hinged or fixed, which in turn transmits the rotary motion, thanks to the interposition of a series of gears. of return and reduction, to the respective mixer shaft.

Generally, the aforementioned electrically powered motor maintains a rotation speed of about 1400 rpm which corresponds, in the respective gearmotor, to a rotation speed reduced by 1⁄2 and, in the mixing shaft, a rotation speed of about 25 revolutions / minute.

In this sector there is a constant need to reduce production costs and assembly times, linked for example to the need to position the components of the gearmotor reciprocally, in a precise and aligned way, as well as to create robust and reliable mixers, which are not subject to excessively frequent maintenance cycles. In particular, there is a need to reduce, if not eliminate, the replacement interventions of the power transmission bevel gear generally used in the traditional gearmotors under discussion. Another need felt is that of reducing the difficulties in procuring spare parts for the gearmotors used. In addition, an important requirement in traditional gearmotors is the cooling capacity, necessary to cope with the strong overheating expected in the three gear reduction stages usually included directly within traditional gearmotors.

An object of the present invention is, therefore, to provide a mixer with horizontal axes provided with a gearmotor which overcomes the drawbacks of the known art, as it does not require special machining for its realization, which does not require the current tight dimensional tolerances for assembly, which is economical, quick to assemble, robust and does not require frequent maintenance and replacement of its components.

In order to obviate the drawbacks of the known art and to obtain this and further objects and advantages, the Applicant has studied, tested and implemented the present invention.

EXPOSURE OF THE FOUND

The present invention is expressed and characterized in the independent claim, while the dependent claims disclose other features of the present invention or variants of the main solution idea. In accordance with the aforementioned purpose, a mixer for concrete, mortar, powders, dry and semi-dry granulates, cement-based or similar or similar mixtures or mixtures, which exceeds the limits of the known art and eliminates the defects present therein, comprises a plurality of rotating shafts for mixing the mixture, arranged horizontally along respective mixing axes parallel to each other, inside a mixing tank, and one or more drive units for driving the rotating shafts in rotation.

According to the present invention, each of the one or more drive units is provided with a motor which has a motorization axis parallel to the mixing axes. Furthermore, in the embodiments described here, one or more gearmotors are provided configured to receive motion from the core or more drive units and connected, through a series of transmission and reduction gears, with the rotating mixing shafts.

The present invention is quick and easy to manufacture, reducing production and assembly costs, without entailing difficulties in procuring spare parts. The solution of creating drive units with an axis motor parallel to the axis of the mixing shafts makes it possible not to provide a power bevel torque for the transmission of the rotation torque. This reduces the need for maintenance and replacement, and the associated difficulties in finding spare parts, thus reducing management costs. The proposed configuration of the motors with axis parallel to the mixing axes also makes assembly faster. In general, with the present invention the reliability and duration of the mixers in question are increased, with minimal maintenance of the moving parts, this also because the invention allows to reduce the operating temperatures thanks to the abundant quantity of oil contained in the tank. containment of the gearmotor itself. In this way, the life of the machine is increased and it is possible to employ personnel assigned to assembly and maintenance of a lower level of preparation and qualification.

In accordance with possible exemplary embodiments, two drive units can be provided, each with its own motor, and two gearmotors, each connected at the input to a respective motor and at the output to a respective rotating mixing shaft.

In accordance with further possible exemplary embodiments, one or two drive units can be provided, each with its own motor, and a single parallel shaft gearmotor, connected at the input to the drive units and at the output to two rotating mixing shafts.

In accordance with embodiments, each motor can be provided with a drive shaft configured to rotate around a corresponding drive axis and is mechanically connected to the gearmotor by means of a flexible closed-loop motion transmission member wound on one side around the drive shaft and on the other side connected to the gearmotor by means of a transmission pulley configured to rotate the set of transmission and reduction gears of the respective gearmotor, thus reducing the number of revolutions.

According to embodiments, the set of transmission and reduction gears of each gearmotor comprises a plurality of toothed wheels mutually meshed and configured to provide a double gear reduction stage inside the gearmotor, in which the axis of rotation of the gearwheels it is parallel to said mixing axes.

In accordance with embodiments described here, a synchronization device is provided kinematically connected to the set of transmission and reduction gears of each of the gearmotors and configured to synchronize the angular phase of rotation and coordinate the rotation movement of the rotating shafts.

In possible embodiments, the synchronization device comprises rotation synchronization bevel pairs, each of which is rotatably connected on one side to the series of transmission and reduction gears of the corresponding gearmotor, and connected to each other by means of a homokinetic swivel joint.

In other possible embodiments, the synchronization device comprises a flexible synchronizing closed-loop transmission member connected on one side and on the other to the series of transmission and reduction gears of each gearmotor. In embodiments, this flexible synchronizing closed-loop transmission member can be combined with a motion reversal mechanism.

According to embodiments, each gearmotor can be mounted in a pendular manner on the mixing tank, in order to be able to oscillate around an axis of oscillation parallel to said mixing axes.

Still, in further embodiments, each gearmotor can comprise a containment case to contain the respective series of transmission and reduction gears and a quantity of cooling oil configured to reduce the operating temperature of the gearmotor.

ILLUSTRATION OF DRAWINGS

These and other characteristics of the present invention will become clear from the following description of embodiments, provided by way of non-limiting example, with reference to the attached drawings in which:

- fig. 1 is a perspective view of a mixer according to embodiments described here;

- fig. 2 is a side view of a mixer according to embodiments described here;

- fig. 3 is a perspective view of drive units of the mixer according to embodiments described herein;

- fig. 4 is a front view of part of the mixer according to embodiments described here;

- fig. 5 is a side view of drive units of the mixer according to embodiments described here;

- fig. 6 is a rear view, in the direction of the arrow F of fig. 5;

- fig. 7 is a schematic view of a part of the drive unit of figs. 5 and 6;

- fig. 8 is a schematic perspective view of parts of the drive unit of figs. 5 and 6;

- fig. 9 is a schematic front view of embodiments of the mixer described here;

- fig. 10 is a schematic bottom view of embodiments of the mixer described here;

- fig. 11 is a schematic perspective view of further embodiments of the mixer described here;

- fig. 12 is a schematic top view of embodiments of the mixer described here.

To facilitate understanding, identical reference numbers have been used wherever possible to identify identical common elements in the figures. Generally, only the differences with respect to the individual embodiments will be described. It should be understood that elements and features of one embodiment can be conveniently incorporated into other embodiments without further specification.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to the various embodiments of the invention, of which one or more examples are illustrated in the attached figures. Each example is provided by way of illustration of the invention and is not intended as a limitation thereof. For example, the features illustrated or described as being part of an embodiment may be adopted on, or in association with, other embodiments to produce a further embodiment. It is understood that the present invention will include these modifications and variations.

Fig. 1 is used to describe embodiments of a mixer 10 with horizontal axes in accordance with the present invention. The mixer 10 under discussion comprises a plurality of rotatable shafts 13 for mixing the mixture to be amalgamated. These rotating shafts 13 can be generally arranged horizontally, typically parallel, inside a mixing tank 12. These rotating shafts 13, moreover, can typically be counter-rotating.

The mixing tank 12 can typically be a parallelepiped structure, usually made of metal material, for example with cylindrical or omega walls, suitable for containing the mixture to be mixed. Typically, the mixing tank 12 can define mixing chambers, for example cylindrical, intersecting each other, which house the aforementioned rotating shafts 13. For example, the mixing tank 12 can be formed by sheet metal parts welded together, or, preferably from entire press-bent metal profiles, thus advantageously increasing the overall rigidity of the mixing tank 12, reducing the welded joints and, where possible, also the thicknesses used. Generally, the aforementioned mixing chambers are physically delimited by respective skirts, for example semi-cylindrical, which substantially constitute the external and lower side walls of the aforementioned mixing chambers. The mixing chambers are thus intercommunicating in correspondence with the axis of symmetry of the relative mixing tank 12 and remain open at the top to facilitate the loading of the components of the mixture into the mixing tank 12. The mixing tank 12 can also be configured to allow the prepared mixture to be unloaded from the bottom by gravity, usually into a conveying hopper.

In a possible typical implementation, the mixer 10 can comprise two rotating shafts 13, and in this case it can therefore be defined as a double horizontal axis mixer (Fig. 2). For example, the rotating shafts 13 can be supported horizontally between the side walls or sides of the mixing tank 12. The rotating shafts 13 define respective mixing axes X that are horizontal and parallel to each other, around which they rotate. Said mixing axes X can therefore be transversal to the side walls, or sides, of the mixing tank 12 (Fig. 2). Typically, these rotating shafts 13 are provided with mixing blades, not visible in the drawings, which intervene on the mixture.

In embodiments, the mixer 10 can comprise one or more drive units 15, each comprising a respective motor 14, such as for example an electric motor, to rotate the rotating shafts 13. For example, many drive units 15 can be provided. how many revolving shafts 13 are to be operated. Or there may be a single drive unit 15 configured to drive all the rotating shafts 13 with which the mixer 10 is provided.

Embodiment examples in which the mixer 10 is provided with two drive units 15, each configured to rotate a respective rotatable shaft 13, are described for example with reference to figs. 1 - 12. It is clear, however, that there could also be a single drive unit 15 configured to rotate two rotating shafts 13.

In embodiments, the mixer 10 can comprise a plurality of gearmotors 16, each configured to receive motion from one or more drive units 15, for example two drive units 15, and to transmit it, at reduced rpm, to the shafts swivels 13 (fig. 3). It is clear that, in some embodiments, a single gearmotor 16 could also be provided which receives motion from one or more motors 14 at its input and which has a plurality of outputs, for example two, for respective rotating shafts 13.

In the following, reference will be made to exemplary and non-limiting embodiments of the scope of protection of the present invention in which two drive units 15 are provided, each comprising a motor 14 connected to a respective gearmotor 16, in turn connected to a relative rotating shaft. 13, without excluding other configurations in which the number of motors 14, gearmotors 16 or rotating shafts 13 can vary.

In possible implementations, the motors 14 can be mounted above the gear motors 16. For example, the 14 can be installed on an upper edge of the mixing tank 12 (Fig. 2). In this case, the use of support plates 18, for example protruding externally from the edge of the mixing tank 12, which support the motors 14 in support, can be envisaged. The gearmotors 16 can be connected in a stable manner to the tank. 12. This connection can be rotatable, as better explained in the rest of the description, or angularly locked.

In other possible embodiments, the motors 14 can be mounted below the gearmotors 16.

For convenience, the following description refers by way of example to embodiments in which the motors 14 can be mounted above the gearmotors 16, but the same description, suitably adapted, also applies to the case in which the motors 14 are mounted below the gearmotors 16. .

In possible embodiments, the motor 14 comprises a drive shaft 19 (see for example Fig. 4) configured to rotate around a drive axis Y.

The motor 14 can be mechanically connected, for example by means of a flexible closed-loop motion transmission member 17, such as a belt, cable or chain, to the gearmotor 16 (Fig. 4). In particular, in embodiments, the flexible closed-loop motion transmission member 17 can wrap around the drive shaft 19 of a respective motor 14. Or, the motor 14 can be directly coupled to the relative gearmotor 16.

Furthermore, typically, the gearmotor 16 can be connected, for example by means of a series of transmission and reduction gears, to a respective rotating mixing shaft 13.

Typically, the motor 14 can be configured to generate adequate power since it must be able, for example with the interposition of the gearmotor 16 and the subsequent series of gears, to drive the respective rotating mixing shaft 13 at a speed of rotation high enough to allow perfect mixing of the dense and heavy mixture poured into the mixing tank 12.

According to aspects of the present invention, each motor 14 is arranged in such a way that the respective motorization axis Y is parallel to the mixing axis X of the connected rotating mixing shaft 13. In this way, the mixer 10 is characterized by being a mixer with a double horizontal mixing axis, with the motorization axes Y of the motors 14 parallel to the mixing axes X of the rotating shafts 13 (see for example Fig. 2).

According to embodiments, each gearmotor 16 used is of the axial type, i.e. the axis of rotation of the power output of the gearmotor 16 is aligned, i.e. coincides, with the mixing rate X of the corresponding rotating mixing shaft 13 (Figs. 1 , 2, 3, 5, 8 and 10). In this way, therefore, also the motors 14 are arranged in parallel axes with their own gearmotors 16.

Each gearmotor 16 is configured to receive the motion from the motors 14 and to transmit it, at reduced speed, to the rotating shafts 13, so that the latter are counter-rotating.

According to embodiments, each gearmotor 16 comprises a transmission wheel, or pulley 20, around which the relative flexible closed-loop motion transmission member 17 is wound. Consequently, two transmission pulleys are provided in embodiments. 20 connected on one side to the two respective motors 14 and on the other side to the two gearmotors 16. In particular, the axis of rotation of the transmission pulley 20 is parallel to the corresponding mixing axis X and therefore also to the relative motorization axis Y .

In possible implementations, each transmission pulley 20 is mounted integral, for example keyed, on a rotating shaft 22, which, as better explained below, rotates the aforementioned series of transmission and reduction gears. Each transmission pulley 20 is configured to realize a first stage of reduction of the number of revolutions supplied by the output of the motor shaft 19 of each motor 14. This first reduction stage, therefore, is external to the gearmotor 16 and, in the case of for example, it is not the gear type.

As can be seen for example in figs. 1 and 3, the use of one or more protective casings 25 may be provided to cover each flexible closed-loop motion transmission member 17 and transmission pulley 20. The casings 25, for example, can be supported by brackets support 32. In the example case, the casings 25 can therefore be positioned in a "V" shape. Depending on the more or less displaced position of the transmission pulleys 20, the casings 25 will consequently be more or less converging or inclined towards each other. Depending on the number or position of the motors 14, the casing 25 can also be only one.

With reference to figs. 5 and 6 are embodiments, combinable with all the other embodiments described here, in which each gearmotor 16 can be mounted in a pendular manner on the mixing tank 12, i.e. connected in a rotatable way. In particular, the pendular assembly of each gearmotor 16 can provide that the latter can rotate, or oscillate, slightly around an oscillation axis P, essentially parallel to the aforementioned rotation axes X and Y respectively of the rotating mixing shafts 13 and of the motors 14. This solution can, for example, allow easier adjustment and maintenance. In particular, slight oscillations admitted by the pendulum assembly of the gearmotor 16 can make it possible to compensate for any greater tolerances with which the set of transmission and reduction gears of each gearmotor 16 can be made.

In possible implementations, in order to achieve the aforementioned oscillation, a pivoting element 23, for example a bushing or sleeve, can be provided for each gearmotor 16 which can be connected to the aforementioned mixing tank 12 (Figs. 5 and 6). This pivoting element 23 can be provided for example on a rear support plate 21 of each gearmotor 16.

In accordance with embodiments, each gearmotor 16 comprises a containment casing 27, in which the aforementioned series of transmission and reduction gears is housed (for example see Figs. 1 to 3). Said containment case 27, which for example can be delimited at the rear by the aforementioned support plate 21, can be of large and adequate dimensions to ensure an abundant quantity of oil contained therein for cooling the parts, which can be even three times greater. of the quantity of oil commonly used in traditional gearmotors. In this way, the need for additional temperature or level sensors is avoided as in traditional gearmotors, which generally require these measures as they are subject to significant thermal changes due to intrinsic operation, as well as for the environments in which they operate. .

According to embodiments, the aforementioned series of transmission and reduction gears of each gearmotor 16 can comprise a plurality of toothed wheels 24, 26, 28, for example cylindrical with helical teeth, which are mutually meshed and configured to form a double gear reduction stage inside the gearmotor 16 itself (see for example Figs. 7 and 8).

In particular, the axis of rotation of the toothed wheels 24, 26, 28 is parallel to the corresponding mixing axis X and therefore also to the relative motorization axis Y. In embodiments described by way of example, three toothed wheels 24, 26 can be provided, 28. The solution with cylindrical gear wheels with helical teeth can be used, for example, for powers from about 45 kW to about 90 kW, while for higher powers, and up to about 130 kW, for example cusp gears can be provided.

It is believed that the greater masses involved in the toothed wheels 24, 26, 28, compared to known solutions, as well as the greater quantity of oil, guarantee continuous operation without the need for level control, if not visual, and monitoring. temperature. Consequently, the risk of seizure is reduced and thermal inertia and the heat exchange surface are increased, this being advantageous for example in hot environments.

For example, experimental tests conducted by the Applicant have shown a temperature reached by the oil up to a maximum of 40 ° C with a surrounding ambient temperature of about 10 ° C, after 8 hours of continuous operation, while for a traditional gearmotor, under the same conditions they can reach 55/60 ° C after only 4 hours of operation. In accordance with possible implementations, a first toothed wheel, or pinion, 24 is set in rotation by the transmission pulley 20 and is configured to transmit in turn the motion, with a reduction of revolutions, to a second toothed wheel 26. The second toothed wheel 26, in turn, is configured to transmit the rotation, with a reduction of revolutions, to a third toothed wheel 28, which, finally, transmits the rotary motion to the respective rotating mixing shaft 13.

In embodiments, the first toothed wheel 24, which typically can be of a smaller diameter than the other two, is rotatably connected to the aforementioned transmission pulley 20. For example, the first toothed wheel 24 can be mounted integral, for example keyed, at one end of the rotating shaft 22, opposite the end on which the transmission pulley 20 is arranged. The movement of the flexible closed-loop motion transmission member 17, rotated by the drive shaft 19, sets the transmission pulley 20 which in turn drives the first toothed wheel 24. In particular, the first toothed wheel 24 is consequently set in rotation by the same rotating shaft 22 which is rotated by the transmission pulley 20. In embodiments, the second toothed wheel 26 meshes with the first toothed wheel 24, receiving its motion from it and consequently being pushed into rotation, with a reduced number of revolutions. In this way it is possible to realize the first reduction stage of the aforementioned double reduction stage inside the gearmotor 16.

Said second toothed wheel 26 can be mounted integrally, for example keyed, on a respective shaft 29. Furthermore, on the same shaft 29 a pinion 31, or similar component with teeth, in the case in question, can be coaxially mounted integral, for example keyed. helical type, typically with a smaller diameter, to achieve an undesired reduction in the number of revolutions. Consequently, the pinion 31 is rotated by the same shaft 29 which is rotated by the second toothed wheel 26. The pinion 31 therefore rotates at the same speed as the second toothed wheel 26.

The third toothed wheel 28, for example having a larger diameter than the second toothed wheel 26, can be mounted integral, for example keyed, on a respective shaft 33, which can in turn be connected to the corresponding mixing shaft 13.

The third toothed wheel 28 receives, with a reduced number of turns, the motion from the second toothed wheel 26, thus being consequently pushed into rotation. In particular, the third toothed wheel 28 can mesh with the aforementioned pinion 31 mounted coaxially with the second toothed wheel 26, from which it is pushed into rotation with reduced revolutions, thus realizing the second reduction stage of the aforementioned double reduction stage inside the gearmotor 16.

In accordance with embodiments, the shaft 33 of the third toothed wheel 28 is connected directly to the rotating shaft 13 for mixing. For example, this connection can be made by means of a toothed sleeve. This can make it possible to preserve the shaft and gearbox from possible breakage in the event of frequent restarts at full load or other improper use of the mixing machine.

According to embodiments, a synchronization device 40 is provided kinematically connected to the gearmotors 16 and configured to synchronize the angular phase of rotation and therefore coordinate the counter-rotating rotation movement of the rotating shafts 13. In this way, thanks to the synchronization device 40 it is It is possible to control the phase rotations of the rotating shafts 13, so that the respective mixing blades do not interfere or collide with each other during the rotation necessary to mix the mixture.

In particular, the synchronization device 40 connects the two drive units 15, coordinating their rotation, so as to preserve the relative phase between the mixing blades. In possible implementations, the synchronization device 40 is connected between the two gearmotors 16, in particular being kinematically connected to the respective series of transmission and reduction gears. A protective casing 45 for the synchronization device 40 may be provided (fig. 6).

Figs. 9 and 10 are used to describe a plurality of possible embodiments in which the synchronization device 40 comprises two bevel synchronizing pairs of rotation 42, provided on one side and on the other by the respective gearmotors 16 associated with the rotating shafts 13 of mixing and to the motors 14. In possible implementations, the bevel gears 42 are made with contained dimensions, configured to provide a synchronized transmission of the rotation movement and not for a power transmission.

Each bevel pair 42 can therefore be connected on one side to the set of transmission and reduction gears of the respective gearmotor 16 and on the other side to the other bevel pair 42, to transmit the rotation motion and essentially coordinate the rotation. of the rotating mixing shafts 13. Each bevel pair 42 is arranged so as to have its own pair of rotation axes oriented according to a pair of Cartesian axes, respectively parallel and orthogonal to the aforementioned mixing axes X and motorization axes Y.

In possible embodiments, the two bevel couples 42 are rotatably connected to each other by means of a homokinetic swivel joint 41. In particular, the homokinetic swivel joint 41 extends along a direction orthogonal to the aforementioned mixing axes X and motorization axes Y. In in this way, thanks to the homokinetic swivel joint 41 connected to the bevel couples 42, it is possible to mutually constrain the movement of the gearmotors 16, to coordinate the phase rotation of the swivel shafts 13.

In possible implementations, the homokinetic swivel joint 41 can be a detachable device for transmitting the rotary motion between two shafts, which keeps the transmission ratio constant over time and equal to 1. For example, the homokinetic swivel joint 41 can be made by arranging two cardan joints in series, or two spatial articulated quadrilaterals.

In accordance with examples of embodiment, each bevel pair 42 of the synchronization device 40 can comprise a first bevel gear 44 and a second bevel gear 46, mutually arranged meshed in the usual way, i.e. at 90 ° with respect to each other. other, so as to convert a rotation around a determined axis into a rotation around an axis orthogonal to it (fig. 8).

The first bevel gear 44 can be arranged with an axis of rotation parallel to the rotation axes of the rotating shafts 13 and of the motors 14.

The second toothed bevel wheel 46 can be arranged with an axis of rotation orthogonal to the rotation axes of the rotating shafts 13 and of the motors 14.

In particular, it can be provided, with reference to one of the two gearmotors 16, with the same description, in a specular way, for the other gearmotor 16, that the first bevel gear 44 is coaxially mounted integral, for example keyed, on the same rotating shaft 22 on which the transmission pulley 20 and the first toothed wheel 24 are mounted. For example, the first toothed bevel wheel 44 is inserted on the rotating shaft 22 alongside the first toothed wheel 24, in the opposite position to the transmission pulley 20, i.e. the first toothed wheel 24 can be, for example, intermediate between the first toothed bevel wheel 44 and the transmission pulley 20. In possible implementations, the second toothed bevel wheel 46 of the described bevel gear 42 can be mounted integral, for example keyed , on a respective rotating synchronization shaft 48. Each bevel pair 42 is arranged in such a way that a free end of the rotating shaft is timing 48 faces inwards, in the direction of the opposite gearmotor, in particular of the other bevel pair 42, typically aligned with the other rotating synchronization shaft 48. Consequently, it is possible to rotate the free ends of the shafts synchronization rotors 48 of the two bevel pairs 42 to obtain the desired synchronization as discussed above. In particular, according to embodiments, the aforementioned homokinetic swivel joint 41 can be connected between the two rotating synchronization shafts 48 of the two bevel couples 42.

Figs. 11-12 are used to describe a plurality of other possible embodiments in which the synchronization device 40 can comprise a flexible synchronizing closed-loop transmission member 49, such as for example a belt, a cable, a chain. The closed-loop synchronizer flexible transmission member 49 can then be connected to the series of transmission and reduction gears of each gearmotor 16, coordinating its rotation. In possible implementations, a respective synchronization pulley 51 can be provided at each gearmotor 16. This synchronization pulley 51 can be arranged with a rotation axis parallel to the rotation axes of the rotating shafts 13 and of the motors 14. The flexible member closed-loop transmission system 49 can then wind around the two synchronization pulleys 51, extending between the two gearmotors 16.

In embodiments, the synchronization device 40 may include a motion reversal mechanism, such as an idle wheel 53. In this way, it is possible to drive the rotatable shafts 13 in a counter-rotating manner. For example, the idle wheel 53 can be mounted coaxially on a shaft 57 on which a respective synchronization pulley 51 is also mounted and can mesh with an intermediate gear 59, such as a toothed wheel, mounted on the rotating shaft 22, which transmits the motion to the aforementioned first toothed wheel 24. In embodiments, a synchronization pulley 51 can be mounted on the same relative rotating shaft 22 on which a relative first toothed wheel 24 of one of the two gearmotors 16 is mounted, for example the one on the right in the figs. 11 and 12. Instead, in the other gearmotor 16, for example on the left in figs. 11 and 12, the other synchronization pulley 51 can be mounted, as mentioned, on the shaft 57 on which the aforementioned idle wheel 53 is mounted. In possible implementations, a tensioning pulley 55, or similar tensioning mechanism, can be provided, to tension the flexible synchronizer closed-loop transmission member 49.

In this way, thanks to the flexible synchronizer closed-loop transmission member 49 it is possible to mutually constrain the movement of the gearmotors 16, to coordinate the phase rotation of the rotating shafts 13. In the embodiments described using figs. 11 - 12, therefore, the synchronization device 40 does not require any synchronization bevel gear, nor a homokinetic joint, but only the aforementioned idle wheel 53 which allows synchronization while having an opposite direction of rotation of the rotating shafts 13 of the mixer 10 Further, in the embodiments described using FIGS. 11 - 12, it is possible to make the gearmotors 16 essentially the same, whether they are mounted on the right side or on the left side, to the full advantage in terms of production costs, warehouse management and logistics.

It is clear that modifications and / or additions of parts can be made to the mixer 10 with horizontal axes described so far, without thereby departing from the scope of the present invention as defined by the claims.

For example, the two drive units 15 can be mounted hinged to the mixing tank. Such a hinged opening system allows you to open and close the motor 14 and gearmotor 16 units, in order to maintain easy and quick access for maintenance, for example to the shaft seals group, without requiring lifting machines.

Furthermore, in further embodiments, combinable for example with embodiments described using figs. 11 and 12, the synchronization device 40 may comprise a pair of gears in place of the flexible transmission member with closed synchronizer loop 49.

Still, in further embodiments, a direct coupling between the motors 14 and the gearmotors 16 can be provided, therefore without the use, for example, of the flexible closed-loop motion transmission member 17 and of the transmission pulley. For example, possible implementations may include the use of 6-pole motors and 900RPM at the input or the use of a reducer with 3 reduction stages and a 1400RPM motor.

It is also clear that, although the present invention has been described with reference to some specific examples, a person skilled in the art will certainly be able to realize many other equivalent forms of mixer, having the characteristics expressed in the claims and therefore all falling within the scope of protection defined by them.

Claims (10)

CLAIMS 1. Mixer with horizontal axes for concrete, mortar, powders, dry and semi-dry granulates, cement-based mixtures or similar or similar mixtures or mixtures, comprising a plurality of rotating shafts (13) for mixing the mixture arranged horizontally along respective axes (X) parallel to each other, inside a mixing tank (12), and one or more drive units (15) to rotate the rotating shafts (13), characterized by the fact that each of the one or more drive units (15) is equipped with a motor (14) which has a motorization axis (Y) parallel to the mixing axes (X) and one or more gearmotors (16) configured to receive motion from one or more several drive units (15) and connected, by means of a series of transmission and reduction gears, with the rotating mixing shafts (13). 2. Mixer as in claim 1, characterized in that each motor (14) is provided with a motor shaft (19) configured to rotate around a corresponding motorization axis (Y) and is mechanically connected to the gearmotor (16) by means of a flexible closed-loop motion transmission member (17) wound on one side around the drive shaft (19) and on the other side connected to the gearmotor (16) by means of a transmission pulley (20) configured to rotate the series of transmission and reduction gears of the respective gearmotor (16) realizing a reduction in the number of revolutions. 3. Mixer as in claim 1 or 2, characterized by the fact that the one or more gearmotors (16) are aligned with the rotating shafts (13) for mixing. 4. Mixer as in claim 1, 2 or 3, characterized in that the set of transmission and reduction gears of each gearmotor (16) comprises a plurality of toothed wheels (24, 26, 28) mutually meshed and configured to produce a double gear reduction stage inside the gearmotor (16), in which the axis of rotation of the toothed wheels (24, 26, 28) is parallel to said mixing axes (X). 5. Mixer as in claims 2 and 4 or 2, 3 and 4, characterized in that each gearmotor (16) comprises a first toothed wheel (24) configured to be rotated by the transmission pulley (20) and to transmit to in turn the motion, with a reduction of revolutions, to a second toothed wheel (26) axially associated with a pinion (31) to transmit the rotation, with a reduction of revolutions, to a third toothed wheel (28) for transmitting the motion rotary to a respective rotating shaft (13) for mixing. 6. Mixer as in any one of the preceding claims, characterized in that it comprises a synchronization device (40) kinematically connected to the set of transmission and reduction gears of each of the gearmotors (16) and configured to synchronize the angular phase of rotation and coordinate the rotational movement of the pivot shafts (13). 7. Mixer as in claim 6, characterized in that the synchronization device (40) comprises rotation synchronization bevel gears (42) each of which is rotatably connected on one side to the series of transmission and reduction gears of the corresponding gearmotor ( 16) and connected to each other by means of a homokinetic swivel joint (41). 8. Mixer as in claim 6, characterized in that the synchronizing device (40) comprises a flexible synchronizing closed-loop transmission member (49) connected on one side and on the other to the set of transmission and reduction gears of each gearmotor (16). 9. Mixer as in any one of the preceding claims, characterized by the fact that each gearmotor (16) is mounted in a pendular manner on the mixing tank (12) to be able to oscillate around an oscillation axis (P) parallel to said mixing axes (X). 10. Mixer as in any one of the preceding claims, characterized in that each gearmotor (16) comprises a containment case (27) to contain the respective series of transmission and reduction gears and a quantity of cooling oil configured to reduce the operating temperature of the gearmotor (16).