The present invention relates to machines for applying labels to packaging, and in particular to a triaxial labelling machine capable of applying labels in different positions and possibly with different orientations on packaging of varying shapes, especially in the food packaging machine sector. In the following, specific reference will be made to the application of the present invention to the aforementioned sector, but it is clear that the labelling machine described in the present application can be used in any other sector where it is necessary to be able to freely vary the positioning of a label on the upper surface of a package.

As is well known, fresh food products such as meat, fish, cheese, fruit, etc. are usually placed in trays or containers which are then sealed with a plastic film, which may be a stretch film or a heat-sealable film suitable for modified atmosphere or vacuum packaging (so-called skin packaging) or another type of film. In any case, the resulting packaging has an irregular shape and height that varies according to the shape and quantity of the food, so the label is applied from above by means of an applicator with a pad equipped with movement along the vertical Z-axis, and possibly rotating around said axis in order to vary the orientation of the label.

The application position of the label on the packaging is determined by a system that moves the applicator along both the transverse X-axis and the longitudinal Y-axis. In known systems, the applicator is typically arranged on a transverse carriage for movement along the X-axis and said carriage in turn moves along the Y-axis. More specifically, the carriage comprises a first motor for moving the applicator along a transverse guide, typically by means of a first toothed belt or the like, and the carriage is in turn moved along two longitudinal side guides by means of two other toothed belts or the like driven by a second motor fixed on the frame of the labelling machine.

This traditional configuration has the drawback of requiring to move back and forth along the Y-axis a rather heavy carriage, since it includes not only the transverse guide and the applicator with its actuator for the movement along the vertical Z-axis, but also the first motor and the first toothed belt for moving the applicator along the X- axis. Consequently, the high inertia of the carriage increases the time for movement and direction reversal along the Y-axis, thus limiting the productivity of the machine, and requires a fixed motor of adequate power with the associated cost and space requirements.

In addition, the presence of two/three motors on the carriage, if the motor for rotating the pad is also present, implies the use of multiple cables that must be connected to the carriage, contributing to the complexity and inertia of the system. The use of three belts also constitutes an element of complexity with negative repercussions on the cost and reliability of the system, as well as the labour required for assembly and maintenance of the system.

DE 8907855U describes a similar device, with the same drawbacks, for the application of image elements reproduced on an adhesive film for the assembly of signs and panels. In this case, the applicator carriage is mounted on a rigid crossbar extending along the X-axis, and the movement of the crossbar along the Y-axis takes place along two parallel tracks by means of a fixed motor on the frame, while the carriage contains three motors for the movement of the applicator along the X-, Z-axes and its rotation about the Z-axis.

The purpose of the present invention is therefore to provide a labelling machine which overcomes the aforementioned drawbacks. This purpose is achieved by means of a labelling machine in which the movement of both the applicator along the X-axis and of the carriage along the Y-axis are obtained by means of a single toothed belt extending both along the longitudinal guides of the carriage and along the transversal guide of the applicator that is fixed to the belt, which is moved by two motors fixed on the frame and acts on the carriage only by means of four deflection rollers carried by the carriage.

The fundamental advantage of the labelling machine in question is therefore that it reduces the mass of the carriage, which no longer includes the motor to move the applicator along the X-axis, nor the associated belt. As a result, the reduced inertia of the trolley reduces the time required to move and reverse direction along the Y-axis, thereby increasing the productivity of the machine, and requires lower power motors with a relative reduction in cost and space required. In addition, having only two fixed motors on the frame reduces the number of cables that must be connected to the carriage and therefore the complexity and inertia of the machine.

Another important advantage of the aforesaid labelling machine is its structural simplicity and low cost due to the use of a single belt instead of three belts, thereby reducing its complexity with positive repercussions on the cost and reliability of the system, as well as on the labour required for assembly and maintenance of the system.

Further advantages and features of the labelling machine according to the present invention will be apparent to those skilled in the art from the following detailed description of an embodiment thereof with reference to the accompanying drawings, wherein:

Fig.1 is a perspective view from above showing schematically the main elements of the movement system of a labelling machine according to the invention;

Fig.2 is a plan view from below of the system of Fig.1;

Fig.3 is a plan view from above of the system of Fig.1;

Fig.4 is a front view of the system of Fig.l; and

Fig.5 is a right-side view of the system of Fig. l.

Referring to the aforementioned figures, it can be seen that a labelling machine according to the present invention traditionally comprises two longitudinal lateral guides 1, 1’ for movement along the Y-axis of a transversal carriage 2, which carries an applicator 3 movable along a double transversal guide 4 for movement along the X-axis. The applicator 3 is also equipped with an actuator for movement along the Z-axis of a pad 6 carrying the label to be applied to the packaging, and with a fan 5 for creating depression inside pad 6 and supporting the labels. A first motor 7 fixed on the frame of the labelling machine, in a front position, drives via a speed reducer 8 a toothed belt 9. The belt 9 is also wound on a rear toothed pulley 10 aligned longitudinally to the speed reducer 8, to achieve the movement of carriage 2 along guide 1 (for simplicity, the teeth on the inner side of belt 9 are not shown in the drawings).

As mentioned above, the innovative aspect of the present invention consists in the fact that the toothed belt 9 not only extends along the left longitudinal guide 1 between the speed reducer 8 and the corresponding rear toothed pulley 10, but also along carriage 2 and the right longitudinal guide 1 ’. More specifically, the labelling machine comprises a second motor 7’ fixed on the frame of the packaging machine, also in a front position, which also acts via a speed reducer 8’ on the toothed belt 9, which is also wound on a corresponding rear toothed pulley 10’ aligned longitudinally with the speed reducer 8’, so that the toothed belt 9 also extends along the right longitudinal guide 1’.

Each of the end portions of the carriage 2 running on the longitudinal guide rails 1, 1’ is provided below with a pair of longitudinally spaced and preferably aligned deflection rollers 11, 11 ’, around which the toothed belt 9 is wound to bend 90° in a transverse direction along the guide rail 4 so that it also extends along carriage 2. In this way, the toothed belt 9 extends in a loop with a substantially H-shaped plan form (Figs. 2-3), according to a path formed by eight sections which can be identified in sequence as follows:

1. between the left speed reducer 8 and the left front deflection roller 11;

2. between the left front deflection roller 11 and the right front deflection roller 11’;

3. between the right front deflection roller 11 ’ and the right speed reducer 8’;

4. between the right speed reducer 8’ and the right rear toothed pulley 10’;

5. between the right rear toothed pulley 10’ and the right rear deflection roller 11’;

6. between the right rear deflection roller 11’ and the left rear deflection roller 11;

7. between the left rear deflection roller 11 and the left rear toothed pulley 10;

8. between the left rear toothed pulley 10 and the left speed reducer 8.

In the embodiment illustrated, applicator 3 is fixed on the second section with the rod carrying pad 6 arranged behind the double guide 4, but the rod could possibly also be arranged in the middle or in front of the latter and/or applicator 3 could be fixed on the sixth section.

Preferably, the toothed belt 9 is not a continuous loop but is cut at applicator 3, which acts as an adjustable connector between the two ends of the toothed belt 9 to make the loop. This configuration has the advantage that the length of the loop does not necessarily have to correspond to a multiple of the tooth pitch of the toothed belt 9, since the distance between its ends can be freely adjusted in the attachment area of applicator 3.

The labelling machine also includes a control unit (not shown) which controls the operation of the two motors 7, 7’ in order to achieve with the single toothed belt 9 all the movements of carriage 2 and applicator 3 as per the following scheme, according to the notations shown in Fig.3. In practice, by simultaneously rotating the motors clockwise (CW) or counter-clockwise (CCW), again with reference to the top view in Fig.3, or by keeping one of the two motors static (S), it is possible to obtain both individual movements along the two transversal and longitudinal directions and simultaneous combined movements along both said directions.

Note that if the applicator were fixed on the sixth section of the toothed belt 9 then the signs of the displacements X in the table would be reversed, i.e. +X would become -X.

It is clear that the embodiment of the labelling machine according to the invention described and illustrated above is only an example susceptible to numerous variations. In particular, the specific type of applicator 3 could be different from that shown and described above, without affecting the movement system which constitutes the essence of the invention. Similarly, the front position of motors 7, 7’ is preferred to facilitate their maintenance/replacement, but the system could be reversed by swapping the position of motors 7, 7’ with that of the toothed pulleys 10, 10’.

The same applies to the definition of the three directions X, Y, Z since it is clear that the labelling machine can be arranged in any spatial orientation and the description only refers to the relative positions between its elements according to the illustrated example.