IT201800020914A1 - GROUP AND METHOD FOR THE TRANSFER AND ORIENTATION OF CONTAINERS - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled: "GROUP AND METHOD FOR THE TRANSFER AND ORIENTATION OF CONTAINERS"

The present invention relates to an assembly for transferring and orienting containers, each having an upper opening defined by a neck portion of the container itself. For example, such containers are defined by bottles or jars. The group object of the present invention can be advantageously integrated into a plant for filling and / or labeling containers.

In fact, in the bottling sector, the need is generally felt to orient the bottles around their vertical axes in order to obtain a pre-defined orientation, for example to be able to quickly and effectively screw a cap onto the neck portion, to close the top opening of the bottles, or to be able to apply a label on the side surface of the bottle body in a desired position.

This need is particularly felt when the bottle body has a rectangular or square cross section.

For this type of bottle, in the known art, guiding elements are commonly used which are arranged in fixed positions and cooperate by friction with the lateral surface of the bottle body while the bottles are transported by a conveyor, for example by a carousel conveyor. .

These solutions are not fully satisfactory, as the bottles can collide or get stuck against the fixed guide elements during their transport.

Furthermore, in cases where recycled material is used to form the bottles, the bottle body can be scratched or damaged after frictional cooperation with the aforementioned guide elements, so that the aesthetic appearance of the final products is compromised, with consequent damage. image for the manufacturer.

More generally, then, the guide elements of the known type do not allow to control the angle of rotation, especially in cases where the bottles have a bottle body with a circular cross section.

The purpose of the present invention is to provide a container transfer and orientation unit, which allows the above problems to be solved in a simple and economical way, in particular allows the containers to be oriented in a flexible manner and independent of the shape of the bottle body, to avoid making any adjustments in the presence of so-called "format changes".

According to the present invention, a container transfer and orientation assembly is provided, as defined in claim 1.

According to the present invention there is also provided a method for transferring and orienting containers, as defined in claim 11.

The invention will now be described with reference to the attached drawings, which illustrate a non-limiting example of embodiment, in which:

- Figure 1 is a top perspective showing, partially and schematically, a first preferred embodiment of the group for the transfer and orientation of containers according to the present invention;

Figure 2 is a front perspective showing, on an enlarged and schematic scale, a detail of the unit of Figure 1;

Figure 3 is a plan view of the detail of Figure 2;

Figure 4 illustrates, on an enlarged and schematic scale, a detail of Figure 2;

Figure 5 is a schematic side view of the detail of Figure 4;

Figure 6 illustrates in perspective and on an enlarged scale a further detail of Figure 1;

Figure 7 is similar to Figure 2 and shows a variant of the group of Figure 1;

- Figure 8 is a top perspective showing, in a schematic and partial way, a second preferred embodiment of the group for the transfer and orientation of containers according to the present invention;

- figure 9 is a schematic perspective, on an enlarged scale and with parts removed for clarity, of a detail of figure 8;

- figure 10 shows the detail of figure 9, in a side view and on a further enlarged scale;

- Figure 11 is a three-quarter perspective showing, schematically and partially, a third preferred embodiment of the group for the transfer and orientation of containers according to the present invention; And

- figure 12 is a side view showing, on an enlarged scale, a detail of the unit of figure 11.

In Figure 1, the reference number 1 indicates a group (partially and schematically illustrated) for transferring and orienting containers 2, which are defined for example by bottles and are preferably made of glass or plastic. Alternatively, the containers 2 can be defined as jars, again in glass or plastic. With reference to Figure 2, each container 2 extends along an axis 3, which in use is vertical, and comprises a body or container portion 4 and a neck portion 5, which has a restricted cross-section, is connected to the portion 4, for example through a truncated cone portion 6, and has an edge 7 defining an opening 8, used to fill the container 2. The opening 8 is adapted to be closed by a cap (not shown), for example by a cap crown type that can be coupled to an external projection (not shown) provided at the edge 6 or by a cap provided with an internal thread, which can be coupled to a corresponding external thread (not shown) provided on the neck portion 5.

With reference to Figures 4 and 5, the neck portion 5 comprises a tubular wall 9, which has a circular cross-section and is preferably cylindrical. The neck portion 5 also comprises two projections 10 and 11, which protrude outwards from an external surface 12 of the wall 9 in axially spaced positions so as to define, between them, a circular seat 13 having a substantially constant height along its perimeter. The seat 13 is adapted to be engaged, in use, by a corresponding support member 14 (schematically and partially illustrated) which vertically supports the wall 9 of the neck portion 5. The projection 10 is the one arranged higher and has a face lower 16 defining a shoulder which rests on the support member 14, while the projection 11 prevents any upward movements and any vibrations of the container 2. According to variants not illustrated, the neck portion 5 is devoid of the projection 11.

In particular, the support member 14 is defined by a gripper comprising two jaws 18, movable horizontally between a closed gripping configuration, in which they clamp the wall 9 together and engage the seat 13, so as to support and / or hold the neck portion 5, and an open release configuration, in which the container 2 is decoupled from the support member 14. The movement of the jaws 18 is obtained in a known way and not illustrated.

In the closed gripping configuration, the jaws 18 define a seat 19 (fig. 3), which is complementary to the outer circular shape of the wall 9 and is configured so as to be engaged by the wall 9 in a rotatable way around a vertical axis of rotation. or joint, indicated by the reference number 20. In optimal working conditions, the axis 20 coincides with the axis 3 of the container 2 which is gripped and transported by the support member 14. According to variants not illustrated, it could be provided a support system different from the jaws 18, but always able to guarantee a free rotation (except for possible frictional forces) of each container 2 around a corresponding axis 20.

With reference to Figure 1, the containers 2 are transported along a path A, lying at least in part on a plane orthogonal to the axes 20 (i.e. on a horizontal plane), and during this transfer they pass through an orientation station 21 where they can be rotated by the group 1 around the respective axes 3 by means of friction forces F (fig. 3) which are tangential with respect to these axes 3. In particular, the group 1 and the station 21 are arranged, along the path A, between a conveyor 22 of the type carousel (schematically illustrated), forming part of a filling plant, and a conveyor 23 of the carousel type (schematically illustrated) forming part of a capping plant.

The group 1 comprises a plurality of dragging elements 24 (fig. 2 and 3) which are operated so as to come into contact with a cylindrical lateral surface of the containers 2, when the latter pass through the station 21, in order to then be able to impose the forces of friction F. According to the present invention, the driving elements 24 are transported along at least one annular path B through the station 21, independently of the movement of the support members 14 and therefore of the containers 2, i.e. in such a way that the elements of dragging 24 can have a speed with a different modulus than that of the containers 2, when they are in contact with the lateral surface of the containers 2 in the station 21. Preferably, the speed of the dragging elements 24 in the station 21 is adjustable, so as to determine whether to actually impose a frictional force F and to determine the magnitude of the difference in velocity (or relative velocity) with respect to the containers 2. More preferably, the group 1 comprises a control unit (not shown) configured in such a way as to regulate the speed of each driving element 24 during the passage through the station 21 in an independent way from that of the other driving elements 24, in particular to control the rotation imparted to each container 2 separately from the orientation control of the other containers 2.

In the embodiment of Figure 1, the unit 1 comprises a single conveyor 25 (schematically illustrated) which transports the support members 14 and the dragging elements 24 along the path B. The support members 14 grasp respective containers 2 from the conveyor 22 and then release them at the conveyor 23, in a known way and not described in detail. Therefore, a part of the path A of the containers 2 coincides with a part of the path B of the driving elements 21. This common part of the path is indicated by the reference letter P in Figure 1 and comprises at least one straight branch R and at least one branch curved convex C arranged downstream of branch R.

With reference to Figures 3 and 4, each of the containers 2 is dragged in rotation around its axis 3 by means of a respective dragging element 24. Each of the dragging elements 24 has an edge 26 which is rectilinear, lying on a plane orthogonal to the axes 20, is parallel or tangential to the path B (ie: parallel to the branch R and tangential to the branch C), is arranged in such a position as to come into contact with the lateral surface of the corresponding container 2 in the station 21 during transport and, during the contact, is oriented tangentially to the axis 20 of the support member 14 which grasps and carries said container 2.

The coefficient of friction between the edge 26 and the lateral surface of the container 2 is sufficient to make the container 2 rotate, without slipping, if there is a difference in speed between the edge 26 and the container 2, i.e. in the case of relative displacement, during contact. To increase the friction coefficient, the edge 26 can be defined by a suitable surface coating, for example made of rubber or other similar material.

The edges 26 delimit respective fingers 27 of the dragging elements 24. Each finger 27 is rigid in bending in the event of stresses or forces acting on the edge 26 in a plane orthogonal to the axes 20,3. In the specific case, the fingers 27 are elongated parallel or tangentially to the path B and project in cantilevered positions and in fixed positions from respective support arms 28, which are part of the dragging elements 24. The arms 28 are transversal to the path B and, in each case operating condition, they are kept spaced from the containers 2, even if they approach (or move away from) the containers 2 when the edges 26 impart the frictional force F.

Preferably, with reference to Figure 5, the edges 26 are in an axial position such as to come into contact with the neck portions 5 of the containers 2. In particular, in station 21, each edge 26 is substantially at the same axial position in which the jaws 18 are located, whereby it touches the surface 12 of the wall 9 in a diametrically opposite position and at the same height as the corresponding support member 14. Therefore, the forces transmitted by the support member 14 and by the dragging member 24 on the container 2 lie on the same plane orthogonal to axis 20 and therefore do not generate any overturning torque. Consequently, the axis 3 remains vertical and coincides with the axis 20, despite the contact between the container 2 and the edge 26.

With reference to what is schematically shown in Figure 4, the support members 14 and the driving elements 24 are brought into fixed positions by respective carriages or slides 30 and 31, which are coupled to one or more guides 32 of the conveyor 25. In in particular, the slides 30 and 31 engage the same guide 32 and are alternated with each other along this guide 32. The slides 30 and 31, the guide 32 and their coupling are shown schematically and / or simplified, as they can be made in various different ways.

Preferably, the conveyor 25 is of the linear electric motor type, whereby the slides 30 and 31 are dragged along the path B under the action of electromagnetic forces. For example, the slides 30 and 31 are provided with respective permanent magnets (not shown). Preferably, the conveyor 25 comprises a single electromagnetic track 33 to operate all the slides 30,31 independently of each other. Alternatively, two parallel electromagnetic tracks could be provided, one to operate the slides 30 and the other to operate the slides 31.

With reference to Figure 3, after the support members 14 have grasped the respective containers 2 from the conveyor 22, in the station 21 each slide 31 can be approached to the slide 30 which is adjacent, or vice versa, when both travel along the branch R, in so as to bring the edge 26 into contact with the corresponding container 2. The free end of the finger 27 is rounded in such a way as to perform a leading function for the edge 27 when the latter comes into contact with the lateral surface of the container 2. Once in contact, the approach between the slides 30 and 31 is made to continue, so as to make the edge 26 slide on this lateral surface, in order to exert the frictional force F and thus impart a desired angle of rotation to the container. 2 (for example according to specific needs required by the capping plant which is arranged downstream). In the illustrated case, the rotation angle is defined by the diameter of the surface 12 and by the relative displacement between the edge 26 and the neck portion 5 during transport along the branch R. Once the desired orientation has been reached, the two adjacent slides 30 and 31 are transported at the same speed (possibly accelerating together with respect to the other slides 30 and 31 arranged upstream, in order to have a minimum distance between the containers 2 along the path A) until reaching branch C. As shown in figure 6, the edge 26 is arranged radially more externally of the corresponding container 2, with respect to the center of curvature of the branch C. Therefore, due to this curvature, the edge 26 autonomously distances itself from the lateral surface of the container 2: at this point, it is it is sufficient to move the slides 30 and 31 away from each other along the branch C, before synchronizing the slide 30 with the conveyor 23 in order to release the container 2 which has been n oriented in station 21.

Figure 7 illustrates a variant which allows to reduce the number of dragging elements 24 on the conveyor 25. In fact, each dragging element 24 is arranged along the path B between two corresponding support members 14a and 14b and comprises two fingers 27a and 27b which protrude in opposite directions from the arm 28 and are capable of orienting respective containers 2a and 2b. Similarly to what is described above, when the support members 14a and 14b grasp the respective containers 2a and 2b from the conveyor 22, the dragging element 24 is decoupled from both containers 2a and 2b. During transport along the branch R, for example, the speed of the slide 31 is increased so as to bring it closer to the slide 30a which supports the support member 14a. The finger 27a is then brought into contact and made to slide on the container 2a which is arranged downstream, to obtain the desired orientation around the axis 3a. At the same time or successively, the slide 30b which supports the support member 14b is accelerated in such a way as to bring it closer to the slide 30 and to cause the finger 27b and the container 2b to cooperate in friction with each other, to obtain rotation around the axis 3b. Obviously, the accelerations and relative movements of the slides 30a, 31 and 30b could be different from this example in order to obtain the sliding required for the fingers 27a and 27b.

Figure 8 relates to a further embodiment, the constituent parts of which are indicated by reference numbers which, where possible, are derived from those of Figures 1-6, to which the value 100 has been added.

With respect to group 1, instead of having a single conveyor, group 101 comprises two conveyors 125a and 125b, which are equal to each other and carry respective series of dragging elements 124a and 124b, along respective ring-shaped paths B; and a conveyor 125c which carries the support members 114 for transferring the containers 102 along the path A and, in particular, is defined by a star or carousel conveyor. The conveyors 125a and 125b are arranged on opposite sides of the path A and, preferably, are of the linear electric motor type, similarly to the conveyor 25.

With reference to Figure 9, in the orientation station 121, the two paths B and the path A comprise respective portions Ta, Tb and Tc which are coplanar and parallel to each other. In light of the curvature of the portion Tc, the portion Ta is concave and the portion Tb is convex, with the same curvature. The conveyors 125a and 125b are counter-rotating, so that the direction of advancement of the containers 102 and of the dragging elements 124a and 124b is parallel and concordant in the portions Tc, Ta and Tb. In particular, in station 121 a single container 102 is oriented at a time, by means of one of the dragging elements 124a and one of the dragging elements 124b, controlled so as to come into contact simultaneously with said container 102 and in such a way as to be synchronized with the speed of advancement of the containers 102 at the start of the contact. In other words, at the beginning of the contact, the speed of advancement of the dragging elements 124a and 124b in the sections Ta and Tb is controlled so as to be equal to that of the containers 102 in the section Tc.

To orient the container 102 which crosses the station 121, during the contact, the speeds of the two driving elements 124a and 124b are one increased and the other reduced so as to generate two opposite relative speeds, but of equal magnitude, with respect to to the container 102, so as to generate a pair of frictional forces (F) on the container 102 around its axis 103. Thanks to this solution, it is possible to rotate each container 102 in any of the two directions of rotation: in the example of Figure 9, if it is the driving element 124a that travels fastest during contact, then the rotation about the axis 103 is clockwise; vice versa, if it is the driving element 124b that travels faster during contact, then the rotation around the axis 103 is counterclockwise. The angle of rotation is defined by the external diameter of the container 102 and by the relative displacement of the dragging elements 124a and 124b with respect to the container 102 itself.

At the end of the orientation operation, in station 121, the speeds of the two dragging elements 124a and 124b are again synchronized with that of the container 102, before the detachment occurs at the end of the sections Ta and Tb.

It is therefore possible to adjust the angle of rotation of each container 102 in a flexible way. In particular, the orientation of each of the containers 102 can be controlled independently of the rotation of the other containers 102.

Unlike the fingers 27 of the group 1, the fingers 127 are elongated and protrude in directions that are orthogonal to the paths B, but still require bending stiffness against forces acting on the edge 126 in a plane orthogonal to the axes 120 (i.e. in a horizontal plane).

As can be seen in Figure 10, the edges 126 of the two driving elements 124a and 124b are arranged in diametrically opposite positions and at the same axial position, so as to avoid torques that tilt the axis 103 with respect to the axis 120. In particular, the edges 126 act by friction on the surface 112 of the neck portion 105, below the projection 111.

According to variants not shown, the edges 126 act on a cylindrical outer surface of the containment portion 104; and / or only one of the conveyors 125a and 125b is provided (in this case, the edges 126 preferably touch the neck portion 105 at the same axial position as the support members 114, similarly to what is seen in unit 1).

Figure 11 relates to a further embodiment, the constituent parts of which are indicated by reference numbers which, where possible, are derived from those of Figures 8-10, to which the value 100 has been further added.

Unlike group 101, in group 201 the conveyors carrying the driving elements 124a and 124b are defined by respective transfer wheels 225a and 225b, which rotate around respective axes 236a and 236b, which are fixed and parallel to the axes 220 of the members support 214, whereby the paths B are circular. In particular, each wheel 225a, 225b comprises a plurality of radial arms 235, each of which supports a relative driving element 224a, 224b.

The radii of curvature of the paths B are smaller than the radius of curvature that the path A has in station 221. The rotation of the wheels 225a and 225b is obtained by operating respective rotary electric motors 237a and 237b. The speed and acceleration of the wheels 225a and 225b are regulated by controlling the motors 237a and 237b in order to obtain the desired relative speed between the driving elements 224a, 224b and the containers 202 in station 221. Similarly to the unit 101, the speed rotation of the wheels 225a and 225b is controlled so that the edges 226 have a speed, in a direction parallel to the path A, equal to that of the containers 202, at the beginning and at the end of the contact in the station 221; and in such a way that, in the intermediate part of the contact, one of the dragging elements 224a, 224b which passes in the station 221 increases its speed (always in a direction parallel to the path A) while the other decelerates by an equal quantity, to obtain the desired orientation angle of the container 202 which is interposed.

The driving elements 224a and 224b comprise respective fingers 227, which protrude radially from the wheels 225a and 225b. The driving elements 224a and 224b are carried by the wheels 225a and 225b in such a way as to have a freedom of movement in the radial direction, in order to compensate for the fact that the paths B are not parallel to the path A in station 221. In particular, along their periphery the wheels 225a and 225b comprise a plurality of radial seats or guides 239 which are each engaged in a sliding manner by the end of a relative driving element 224a, 224b. In particular, the driving elements 224a and 224b are able to slide along the respective guides 239 towards the respective axes 236a, 236b starting from respective rest positions against the action of elastic elements, defined for example by springs 240. Therefore , after each dragging element 224a and 224b has come into contact with the side surface of a corresponding container 202 at the entrance to station 221, continuing to rotate around the axis 236a, 236b said dragging element 224a and 224b partially falls within the respective guide 239 starting from its rest position, against the reaction force of the corresponding spring 240. Once a dead point has been passed in which the driving elements 224a and 224b in station 221 are radially aligned with both axes 236a and 236b, the dragging elements 224a and 224b come out of the guides 239 under the thrust of the respective springs 240 to return to the positions of original rest.

The distance between the path A and the axes 236a and 236b, the radii of curvature of the paths B and the maximum radial travel of the dragging elements 224a and 224b in the respective guides 239 are established in such a way that the edges 226 of the fingers 227 they are in contact with the external surface of the containers 202 for a length sufficiently long to obtain the desired angles of rotation.

As described above for the unit 101, by controlling the motors 237a and 237b for each pair of driving elements 224a and 224b which engage the station 221, it is possible to rotate the corresponding container 202 in any of the two directions of rotation. Furthermore, it is possible to vary the speed of rotation of the wheels 225a and 225b for each pair of driving elements 224a and 224b which engage the station 221 independently of the control carried out for the other driving elements 224a and 224b, so as to adjust the orientation of each of the containers 202 independently of the rotation of the other containers 202.

The advantages of the group 1, 101 and 201 appear evident from the above description.

In particular, it is evident how the unit of the present invention allows to orient the containers of the desired angle in a controlled manner and, preferably, to differentiate the rotation angle between the various containers.

Furthermore, the unit of the present invention allows to operate on the neck portions 5, 105, 205, whereby it avoids scratches or damage on the external surface of the containment portion 4, 104, 204, thus guaranteeing the aesthetic value even if the material of this containment portion were of relatively low quality and / or hardness.

The group 1 and 101 use linear motors which allow to control the displacements of the driving elements 24 and 124a, 124b in a precise way and to obtain relatively high speeds (so that the number of the driving elements 24 and 124a, 124b in each conveyor can be relatively low). On the other hand, group 201 has an extremely simple solution from the construction point of view, while maintaining the ability to control the rotation angle of containers 202.

The solution of the group 1 is extremely compact, since it provides a single conveyor 25 which carries both the driving elements 24 and the support members 14.

Still in group 1, the transfer and orientation of the containers 2 along the branch R reduces the effects due to backlashes (commonly called "backlash", in English), i.e. it reduces the unwanted product spillage, which can occur during the transport and orientation of the containers along paths in which speed and / or direction changes are foreseen.

Furthermore, the conveyor 25 can replace in a relatively simple way the star conveyor which is normally provided in known solutions for the transfer of containers 2 between the conveyors 22 and 23, i.e. between the filling and capping systems.

Finally, it appears evident from the foregoing that modifications and variations may be made to the unit 1, 101, 201 described with reference to the attached figures which do not go beyond the scope of protection of the present invention, as defined in the attached claims.

In particular, the conveyors 22, 23, 25, 125a, 125b, 125c and 225c could be different from what is indicated above as preferred examples of embodiment; and / or the control unit of the group 1, 101, 201 could be configured so as to always impart the same relative speed to the dragging elements 24, 124a, 124b and 224a, 224b with respect to the containers 2, 102, 202, for rotate all the containers 2, 102, 202 by the same angle, or it could be configured to rotate only some of the containers 2, 102, 202 which are transported through the station 21, 121, 221.

Finally, as mentioned above, the containers 2, 102, 202 could be transported in a different way from the preferred one, which has been shown, where support members 14 are provided which grip the neck portion 5, 105, 205: for example , especially in the solutions relating to the groups 101 and 201, the containers 102 and 202 could be transported in a row while the bottom of their containment portion 104, 204 is arranged to rest vertically on respective portions of a transport surface (for example on respective portions of a conveyor belt), with the possibility of rotation around its own axes 103 and 203 on this transport surface.

Claims (1)

CLAIMS 1.- Group (1; 101; 201) for transferring and orienting containers (2; 102; 202), each having an axis (3; 103; 203) and comprising: - a containment portion (4; 104; 204); - a neck portion (5; 105; 205) connected to said containment portion and defining an opening; the group including: - support portions (14; 114; 214) adapted to support respective containers and defining respective articulation axes (20; 120; 220) around which the supported containers are free to rotate; - conveying means (25; 125a, 125b, 125c; 225a, 225b, 225c) to transfer said support portions (14; 114; 214) along a first path; - dragging elements (24; 124a, 124b; 224a, 224b) arranged in positions such as to come into contact with said containers and exert frictional forces (F), tangential with respect to said articulation axes (20; 120; 220), on the containers supported by said support portions (14; 114; 214) during the transfer, in order to orient the supported containers around the respective articulation axes; characterized in that said driving elements (24; 124a, 124b; 224a, 224b) are mobile, under the action of said conveying means (25; 125a, 125b, 125c; 225a, 225b, 225c), along at least one second path (B) shaped as a ring and independently from said support portions (14; 114; 214), so that each said driving element (24; 124a, 124b; 224a, 224b) can exert said friction force (F ) due to a relative speed with respect to a corresponding container (2; 102; 202) during contact with said corresponding container (2; 102; 202). 2.- Group according to Claim 1, characterized in that said driving elements (24; 124a, 124b; 224a, 224b) comprise respective fingers (27; 127; 227), which are rigid in bending when subjected to direct forces in a plane orthogonal to said articulation axes (20; 120; 220). 3. Group according to Claim 1 or 2, characterized in that said conveying means comprise at least one linear motor conveyor (25; 125a, 125b) which carries said driving elements (24; 124a, 124b). 4.- Group according to Claim 1 or 2, characterized in that said conveying means comprise at least one transfer wheel (225a, 225b), which is rotatable around an axis of rotation (236a, 236b) parallel to said articulation axes (220); said dragging elements (224a, 224b) being supported by said transfer wheel (225a, 225b) so as to be able to move along respective directions which are radial with respect to said rotation axis (236a, 236b). 5.- Group according to any one of Claims 1 to 3, characterized in that said conveying means comprise a single conveyor (25) which transfers the said support portions (14) and the said dragging elements (24) along a common path (P). 6.- Group according to Claim 5, characterized in that said common path (P) comprises at least one straight branch (R) and at least one curved convex branch (C); each of said dragging elements (24) being arranged adjacent to at least one of said support portions (14), along said common path (P), and being operated so as to exert said frictional force (F) on the container supported by the adjacent support portion, when they both move along said straight branch (R). 7.- Group according to any one of claims 1 to 4, characterized in that said conveying means comprise two conveyors (125a, 125b; 225a, 225b) which are arranged on opposite sides of said first path (A) and support said dragging elements so as to transfer said dragging elements along respective second paths (B) which are shaped like a ring. 8.- Group according to any one of the preceding claims, characterized in that said dragging elements (24; 124a, 124b; 224a, 224b) are arranged in axial positions such as to come into contact, in use, with said containers only in correspondence of said neck portions (5; 105; 205). 9.- Group according to Claim 8, characterized in that said support portions (14) are defined by support members configured so as to grip said containers (2) in correspondence with said neck portions (5); said dragging elements (24) and said support members being arranged at the same axial position. 10.- Unit according to any one of the preceding claims, characterized in that it comprises control means configured so as to regulate said relative speed for each of said driving elements (24; 124a, 124b; 224a, 224b) independently from that of the other driving elements (24; 124a, 124b; 224a, 224b). 11.- Method for transferring and orienting containers, each having an axis and comprising: - a containment portion; - a neck portion connected to said containment portion and defining an opening; the method including the steps of: - transferring a plurality of containers along a first path (A), so that said containers are free to rotate around respective articulation axes (20; 120; 220) during the transfer; - orienting at least some of said containers around the respective articulation axes (20; 120; 220), exerting frictional forces (F), tangential to said articulation axes (20; 120; 220), by means of dragging elements (24; 124a, 124b; 224a, 224b) which come into contact with said containers during the transfer; characterized in that, during the transfer of said containers, said frictional forces are exerted by moving said dragging elements (24; 124a, 124b; 224a, 224b), each with a relative speed with respect to a corresponding container during contact with said corresponding container. 12. A method according to Claim 11, characterized in that said dragging elements (24; 124a, 124b; 224a, 224b) come into contact with the containers only at said neck portions. 13.- Method according to Claim 11 or 12, characterized by controlling the displacement of said driving elements (24; 124a, 124b; 224a, 224b) so as to regulate said relative speed for each of said driving elements (24 ; 124a, 124b; 224a, 224b) independently from that of the other driving elements (24; 124a, 124b; 224a, 224b).