ITBO20060374A1 - METHOD AND DEVICE FOR THE PRODUCTION OF PRODUCTS - Google Patents

Abstract

In a method for wrapping products such as items of confectionery, each product (1) is first enveloped in part by a respective leaf (2) of wrapping material so as to create an intermediate wrap presenting a first flap (3) and a second flap (4), projecting from the product (1) on either side of one face (5) that remains exposed initially. The first flap (3) is then bent in a direction (Fl) causing it to rotate inwards and cover the exposed face (5) of the product (1), while also closing on the second flap (4) in such a way that an area (7) of mutual contact is established between the two flaps (3, 4), whereupon the first and second flaps (3, 4) are bent further in the same direction (F1) and flattened against an adjoining flank face (5a) of the product (1), so as to form a semi-finished tubular wrapper (8). Finally, the two ends (9) of the tubular wrapper (8) are sealed, preferably by fashioning twist closures (10).

Description

DESCRIPTION

of the industrial invention entitled:

"Method and device for wrapping products"

The present invention relates to a method and a device for wrapping products.

The present invention finds advantageous application in the field of continuous packaging of food products, such as chocolates, candies and the like, to which the following discussion will explicitly refer without losing generality.

In wrapping machines it is known to step and feed in an orderly manner a succession of products along a determined path to a pick-up station to be gripped by respective transfer members and to be advanced, first to a loading station in which it is coupled to each product. a relative wrapping sheet and, progressively, through a succession of folding stations able to form a closed wrapping around each product to be wrapped.

Known devices generally comprise a wrapping drum provided with peripheral gripping units, such as grippers or seats, adapted to hold and advance the products partially wrapped in a wrapping sheet, arranged in a "U" shape around the product, along a predetermined path and through special bending stations. The folding operations, to which each U-folded sheet must be subjected to obtain a closed wrapping, involve a first folding operation of each of the two lateral ends of the sheet that protrudes beyond the corresponding lateral end of the relative product, up to forming a partial tubular envelope that surrounds the aforementioned product. Subsequently, the open longitudinal ends of the tubular casing are closed with the formation, for example, of butterfly knots.

Such a method is illustrated in document EP08 16229, which shows a device for wrapping products in a package with butterfly knots. The device is capable of arranging a sheet of wrapping material partially around a product, so as to form a partial wrapping folded substantially in a "U" shape around the product itself. A flap of the wrapping sheet protrudes from each of the two sides of the product and the two flaps develop parallel and protrude beyond the product to be wrapped. Subsequently, only one of the two flaps is turned over and placed against a sealing area of the other flap and adheres to the latter. Subsequently, the other flap, together with the adherent portion of the flap turned first, is turned in the opposite direction to the direction of overturning of the flap turned first and pressed against the aforementioned first flap to form a seal. After the steps described above, both flaps adhere to the product and the wrapping sheet forms a tubular envelope that wraps the product itself. Finally, the longitudinal ends of the tubular casing are closed with the formation of butterfly knots.

This type of folding method is quite complex since the two flaps protruding from the product must be folded in opposite directions. Therefore, the device designed to perform these steps must necessarily be provided with elements in reciprocal motion which act in different directions and directions, such as to complicate the structure of the device and to negatively affect its production and maintenance costs.

The aim of the present invention is therefore to propose a method and a device which are free from the drawbacks described above.

In particular, it is the aim of the present invention to propose a method for wrapping products that is quick and simple to implement. It is also the aim of the present invention to propose a device for wrapping products that is structurally simple and, therefore, economical and efficient.

According to the present invention, a method is provided for wrapping products according to one or more of claims 1 to 18.

The present invention also relates to a device for wrapping products in accordance with one or more of claims 19 to 28.

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

Figures 1a show a succession of operating steps for wrapping products according to the method in accordance with the present invention;

Figures 2a-2d show a variant of the succession of operating steps according to the method in accordance with the present invention; - Figure 3a illustrates in perspective a partially wrapped product following the method according to the invention;

- Figure 3b illustrates a fully wrapped product obtained by following the method according to the invention;

- Figures 4a-4f show portions of a device for wrapping products according to the present invention, in their respective operating configurations during the execution of the phases of figures 1a;

- figures 5a-5d show portions of an alternative embodiment of the device of figures 4a-4f, in respective operating configurations during the execution of the steps of figures lalc;

figure 6 is a perspective view of the portion of the device of figure 5d; And

Figures 7a-7d show a further variant of the succession of operating steps according to the method in accordance with the present invention.

With reference to the attached figures, the reference number 1 indicates a product intended to be wrapped according to the method of the present invention.

The product 1 is for example a chocolate, a candy or a similar food product with a parallelepiped shape but this shape is only an example and therefore not limiting. Such product 1 could be a spherical or oval shaped sugared almond.

The product 1 is first of all partially wrapped in a wrapping sheet 2, so as to define an intermediate wrapping having a first wing 3 and a second wing 4 arranged on opposite bands with respect to a free surface 5 of the product 1 and protruding from this product 1 . By free surface 5 we mean the only lateral surface of the product 1 which, at the end of this first phase of the method, is not associated, or in contact, with the sheet 2. The sheet 2 therefore assumes a substantially "U" shape. Which partially wraps the product 1 leaving the free lateral surface 5 and the two opposite end surfaces 6 of the product 1 uncovered, only one of which is visible in the attached figures (figures la and 2a). As illustrated, the sheet 2 is associated with three sides of the product 1 while the fourth side remains uncovered.

In the sequence of figures la- le, at the end of the partial wrapping phase (figure la), the first wing 3 and the second wing 4 extend reciprocally away from each other starting from opposite edges of the product 1 and both lie substantially coplanar with the surface 5 free of the aforementioned product 1.

In the sequence of figures 2a-2d at the end of the partial wrapping phase (figure 2a), the first wing 3 and the second wing 4 develop parallel to each other and substantially perpendicular to the free surface 5.

Subsequently, only the first wing 3 is bent in a predetermined direction F1 (counterclockwise in Figures 1a-2d) towards the free surface 5 of the product 1 and towards the second wing 4 and brought against the second wing 4, to form a zone 7 of mutual contact of the first and second wings 3, 4.

This area 7, or a portion of the first wing 3 only or the second wing 4 or both, is rubberized, or provided with a layer of cold glue, so as to ensure the longitudinal sealing of the envelope obtained with the sheet 2 of wrapping. Alternatively, the zone 7 could be sealed with hot glue or by welding.

In the sequence of figures la and lb, the first wing 3 rotates about 180 ° around a line parallel and close to an edge of the product 1 until it covers the free surface 5 of the product 1 and the second wing 4 (figure lb) .

In the sequence of figures 2a and 2b a proximal portion of the first wing 3 first rotates around the aforementioned parallel line of about 180 °, while a distal portion of the same first wing 3 first rests against the second wing 4 and then, together with this completes the rotation until it substantially reaches the same configuration as in figure 1b (figure 2c).

Preferably, once the association of the two wings 3, 4 is completed, the aforementioned two wings 3, 4 are pressed against each other in the reciprocal contact area 7 to complete the longitudinal sealing.

With reference to the succession of phases of figures 1a, this pressing phase is performed while the two wings 3, 4 lie superimposed and parallel to the free surface 5 (figure 1b), or at the end of the bending phase of the aforementioned first wing 3 against the second wing 4.

In the succession of phases of figures 2a-2d, the pressing can be performed when the first wing 3 comes into contact with the second 4 (figure 2b) or after the second wing 4 has also completed the rotation and has moved into the same configuration. of figure 1b (figure 2c).

Subsequently, the first wing 3 together with the second wing 4 are folded again in the predetermined direction F 1 and against the product 1, so as to form a tubular wrapping 8 (Figure 3 a).

According to what is illustrated in figures 1a and 2d, the first wing 3 and the second wing 4 are folded together against a side 5 a of the product 1 substantially perpendicular to the free surface 5. The pressure of the first wing 3 against the second wing 4, which in the preferred embodiment is carried out before folding the first wing 3 together with the second wing 4 against the product 1, could be carried out against the product 1 itself, once this folding has been completed. .

It is also important to underline that the succession of phases described above may or may not be performed continuously, i.e. without any interruption between one passage and the next, and the subdivision as detailed above only serves to clarify the movements given to sheet 2 of wrapping.

Finally, the longitudinal ends 9 of the tubular wrapping 8 which extend beyond the product 1 are closed and sealed, by means of cold or hot glue or welding, preferably with the formation of staple knots 10, according to a process known per se and therefore not further detailed (Figure 3b).

The method described above can be performed by means of a device 11 for wrapping products 1 according to the invention which is part of a wrapping machine, not shown as a whole.

The device 11 comprises a conveyor 12, which conveyor 12 has a plurality of seats 13 arranged in succession and advancing along a predetermined path 14 and in a predetermined direction F2.

In both embodiments illustrated in Figures 4a-4f and 5a-5d, the conveyor 12 is a wrapping wheel 12 supported by a wall 15 of the wrapping machine and rotatable around a horizontal axis 16 perpendicular to the wall 15 itself, with angular speed substantially constant (clockwise in the attached figures) according to the arrow F2. The predetermined path 14 therefore has a shape of an arc of a circle. In alternative and not illustrated embodiments, the aforementioned path 14 could still take on another shape such as, for example, the straight one.

Each seat 13 is adapted to receive a product 1 partially wrapped in the wrapping sheet 2 with the first wing 3 and the second wing 4 protruding from the aforementioned seat 13.

In the preferred embodiment and illustrated in Figures 4a-4f, each of the seats 13 is defined by gripping ends 17 of a respective main gripper 18. The main pliers 18 are preferably mounted angularly equally spaced on the wrapping wheel 12 and develop in a radial direction from the rotation axis 16. In the alternative embodiment, illustrated in Figures 5a-5d, each of the seats 13 is delimited by a pocket 19 formed in the cylindrical side wall of the wrapping wheel 12. Also in this embodiment, the pockets 19 are preferably angularly equally spaced.

In order to place each product 1 partially wrapped in the sheet 2 inside a respective seat 13, the device 11 comprises a loading station 20 located near the predetermined path 14.

The loading station 20 comprises a pusher 21 movable transversely to the predetermined path 14 between a position for moving away from the predetermined path 14 and a position of approaching the aforementioned predetermined path 14, so as to push each product 1 against the sheet 2 of wrapping, which it lies parallel to the aforementioned predetermined path 14, in a radially external position with respect to the seats 13 and facing a respective seat 13, and inside the seat 13 itself. During insertion, the product 1 therefore drags with it the sheet 2, which is arranged on the three sides of the product 1, between the product 1 itself and the internal walls of the seat 13. The wings 3, 4 that protrude from the seat 13 remain parallel to the predetermined path 14 and rest at least in part against peripheral support surfaces 22 of the wheel 12 interposed between the seats 13 and also substantially parallel to the aforementioned path 14. This configuration of the whole "product 1-sheet 2" corresponds to that illustrated in figure la.

In the embodiment of figures 4a-4f the supporting surfaces 22 are defined by terminal portions of the pincers 18 while in the alternative embodiment of figures 5a-5d the same supporting surfaces 22 are defined by portions of the conveyor 12, or of the cylindrical side wall of the wrapping wheel 12, interposed between the pockets 19.

The device 11 also comprises a fixed abutment 23, mounted close to the predetermined path 14, to intercept in succession the wings 3, 4 of each wrapping sheet 2 and cause the folding of the first wing 3 in the predetermined direction F1, opposite to the direction F2 of advancement of the products 1, towards the free surface 5 of the product 1 and against the second wing 4.

In the illustrated figures, the fixed abutment 23 is a tile which has a curved surface 24 facing and close to the supporting surfaces 22, so as to delimit together with these supporting surfaces 22 a passage 25 for the wings 3, 4. The tile 23 is also provided with an engagement edge 26 close to the supporting surfaces 22 and facing the loading station 20. The distance of the edge 26 from the support surfaces 22 is such as to cause the interference of the edge 26 itself with the first wing 3 and the overturning of the same first wing 3 on the product 1 and on the second wing 4 (Figure 4c). This configuration of the "product 1-sheet 2" assembly corresponds to that illustrated in figures 1b and 2c.

In order to hold the wings 3, 4 against the aforementioned supporting surfaces 22 during insertion and before the wings 3, 4 reach the abutment 23, the device 11 is equipped with holding means 27, which operate on end flaps of each sheet 2 before folding.

In figures 4a-4f these means are not shown while in figures 5 a and 5b, two blades 28 are superimposed on the active surfaces 22 and lie side by side with a respective seat 13 while this seat 13 is located in the loading station 20.

In addition to or as an alternative to retaining means of the mechanical type, vacuum systems may be present. For example, in the embodiment of figures 5a-5d, the device 11 is also provided with ducts 29 communicating with an aspirator 29a (shown only schematically), which ducts 29 open onto an upper surface 30 of the tile 23 close to the engagement board 26. The upper surface 30 is substantially flat and parallel to the predetermined path 14 for advancing the products I at the loading station 20. The first wing 3 of the wrapping sheet 2 is held on this flat surface 30 before and during the insertion of the product 1 and of the sheet 2 itself in the respective seat 13. The upper surface 30 and the lower surface 24 curved of the tile 23 converge towards the edge 26 of commitment.

The device 11 also comprises a sealing station 31 located along the predetermined path 14 downstream of the fixed abutment 23. The function of this station 31 is to complete the longitudinal sealing in correspondence with the area 7 of mutual contact between the wings 3, 4. In the illustrated embodiments, in which the sealing takes place by means of cold glue, this station 31 performs the pressing of the two wings 3, 4 against each other.

More particularly, in the first embodiment of Figures 4a-4f, the sealing station 31 comprises a pair of pressers 32, 33 moving towards or away from each other along a direction transversal to the predetermined path 14 and acting on opposite sides of the aforementioned reciprocal contact zone 7 (Figure 4d). The pressers 32, 33 move along a radial direction with respect to the axis 16 of rotation of the wrapping wheel 12 and are arranged in such a way that the two wings 3, 4, already associated, are found between the pressers 32, 33 themselves. The device 11 can, for example, comprise many radially internal pressers 32 mounted on the wrapping wheel 12 and each flanked by a respective gripper 18 and a single radially external presser 33 installed in the sealing station 31.

According to what is illustrated in the second embodiment of Figures 5a-5d, the sealing station 3 1 comprises a presser 34 associated with the supporting surfaces 22, to press the reciprocal contact area 7 against one of these supporting surfaces 22 and therefore the two wings 3, 4 against each other.

In particular, the presser 34 comprises a roller 35, which roller 35 is preferably installed in a housing 36 obtained in an end portion 37 of the tile 23 opposite the edge 26 (Figure 5c). Preferably, the wheel 35 is furthermore constrained to the tile 23 by elastic means 38 able to push the wheel 35 against the supporting surfaces 22. When the wings 3, 4, which lie on one of these surfaces 22, are carried by the rotation of the wrapping wheel 12 under the wheel 35, the latter presses them against each other.

Along the predetermined path 14, downstream of the fixed abutment 23 and of the sealing station 3 1, with respect to the direction F2 for the advancement of the products 1, there is also a folding station 39 capable of folding the first wing 3 together with the second wing 4 again in the predetermined direction F1, ie in a direction concordant with the folding of the first wing 3 only, and against the product 1. This configuration of the assembly "product 1 - sheet 2" corresponds to that illustrated in figures 1a, 2d and 3a.

As illustrated in Figure 4e, an auxiliary gripper 40 is installed in the folding station 39 capable of temporarily holding the product 1 released from the main gripper 18 during folding. The auxiliary gripper 40 is oriented transversely with respect to the main gripper 18 and has two gripping ends 41, of which only one is shown in Figure 4e, which engage with the head surfaces 6 of the product 1. The auxiliary gripper 40 is movable between one operative position close to the main gripper 18 which is in the folding station 39 and an inoperative position, in which it lies spaced from the wrapping wheel 12, so as not to interfere with its motion. In the operative position, the jaws 41a of the auxiliary gripper 40 are arranged around one of the gripping ends 17 of the main gripper 18 and are sufficiently spaced from each other so as not to interfere with this end 17 when their gripping ends 41 clamp onto the product 1.

A folder 42 is movable along a radial and transverse direction to the feed path 14 and is inserted between the open ends 17 of the gripper 18, to intercept the contact area 7 and place it against a side of the product 1. Therefore, having reached station 39 the product 1 is grasped by the auxiliary gripper 40 and released by the main one 18. Subsequently, the folder 42 is inserted between the product 1 and the end 17 of the main gripper 18 located on the opposite side with respect to the auxiliary gripper 39, intercepts wings 3, 4 and touches the side of the product 1 to bend against the aforementioned wings 3, 4.

Once the tubular wrapping 8 has been formed, the main gripper 18 closes on the product 1 and the auxiliary gripper releases it (Figure 4f). The product 1 is brought to a further closing station equipped with means, of a type known per se and therefore not illustrated, to close the longitudinal ends 9 of the tubular wrapping 8. Preferably, these means are adapted to form the staple knots 10.

In the alternative embodiment, according to what is illustrated in Figure 5d, in the folding station 39 there is positioned a pick-up gripper 43 which cooperates with an auxiliary pusher 44 slidably inserted in the pocket 19. The auxiliary pusher 44 is movable between a rear position, in which lies on the bottom of said pocket 19, and an advanced position, in which it lies in proximity of the opening of said pocket 19. Each pocket 19 is equipped with an auxiliary pusher 44, which, when the pocket 19 is in the station 20 of loading, it moves from the forward to the back position, to accompany the entry of a product 1 into the pocket 19 itself, while, when the pocket 19 is in the folding station 39, it moves from the back to the forward position, to push the product 1 out of the pocket 19 and between the jaws 45 of the pick-up gripper 43. During this motion of the product 1, one of the jaws 45 acts as a bender, since it intercepts the wings 3, 4 and folds them against one side of the product 1.

More in detail, the folding station 39 lies next to the sealing station 31, immediately downstream of the terminal portion 37 of the tile 23. The terminal portion 37 itself has a projection 46 which extends radially with respect to the axis 16 of the wheel 12 of wrapping and is provided with counter-shaped radial grooves 47 with prongs 48 of one of the jaws 45 of the pick-up gripper 43 (Figure 6).

The pick-up gripper 43 is movable between a position spaced from the projection 46 and an engagement position, in which the prongs 48 are inserted in the grooves 47, to provide a continuous support surface for the product 1 partially wrapped in the wrapping sheet 2. The projection 46 also cooperates with the prongs 48 in bending the wings 3, 4 against the product 1.

Once the passage of the product 1 wrapped in the tubular wrapping 8 from the pocket 19 to the pick-up gripper 43 has been completed, the latter closes on the wrapper 8 and takes the product 1 to a further closing station equipped with means for closing the longitudinal ends 9 of the tubular wrapping 8, for example, with the formation of the staple knots 10.

According to what is illustrated in figures 7a-7d, which show a further embodiment, the first wing 3 and the second wing 4 are arranged parallel to each other and perpendicular to the surface 5. The sheet 2 thus assumes a substantially "C-shaped" conformation. ”Leaving the surface 5 of the product 1 free, similarly to what was previously described (Figure 7a).

The two wings 3, 4 are then simultaneously folded towards each other, making the wing 3 rotate, at least partially, clockwise with respect to figure 7a, until the wings 3, 4 are associated with each other, by means of heat welding. or cold, in an intermediate zone arranged on the surface 5 and included between a surface 5b, similar to said side 5a, and the surface parallel to it and opposite to the product 1 (Figure 7b).

The first wing 3, associated with the second wing 4, is then rotated, in a direction concordant with the rotation that the wing 3 itself has previously performed, until the wing 4 is arranged parallel to the surface 5 and included between the surface 5 itself and the 'wing 3 (Figure 7c). If the dimensions of the length of the wings 3, 4 with respect to the surface 5 require it, the terminal portions of the wings 3, 4 themselves can be further folded, again with a clockwise rotation, until they are arranged parallel to the surface 5b of the product 1 ( figure 7d).

Note that the wings 3, 4 can be associated with each other by welding not only in the phase illustrated in figure 7b, but also in the phase illustrated in figure 7c or even in the last phase illustrated in figure 7d.

Claims (28)

R I V E N D I C A Z I O N I 1) Method for wrapping products, characterized in that it comprises the steps of partially wrapping a sheet (2) of wrapping around a respective product (1), to define an intermediate wrapping having a first wing (3) and a second wing (4) arranged on opposite bands with respect to a free surface (5) of the product (1) and protruding from said product (1); fold at least the first wing (3) in a predetermined direction (FI) towards the surface (5) of the product (1) and bring said first wing (3) against the second wing (4), to form an area (7) of mutual contact of the first and second wings (3, 4); folding the first wing (3) together with the second wing (4) in said predetermined direction (F1) and against the product (1), to form a tubular wrapping (8); closing longitudinal ends (9) of said tubular wrapping (8). 2) Method according to claim 1, characterized in that at the end of the partial wrapping phase, the first wing (3) and the second wing (4) extend away from each other and both lie substantially coplanar with the free surface (5) of the product (1). 3) Method according to claim 1, characterized in that the first wing (3) and the second wing (4) are folded together against a side (5a) of the product (1) substantially perpendicular to the free surface (5). 4) Method according to claim 1, characterized by the fact of joining the first wing (3) to the second wing (4) in the reciprocal contact area (7), to define a longitudinal sealing of the tubular wrapping (8). 5) Method according to claim 4, characterized by the fact that the union between the first wing (3) and the second wing (4) is carried out by means of a cold glue placed on the reciprocal contact area (7) before folding the first wing (3) against the second wing (4). 6) Method according to claim 4 or 5, characterized in that the first wing (3) is further pressed against the second wing (4) in the reciprocal contact area (7). 7) Method according to claim 6, characterized in that the pressure of the first wing (3) against the second wing (4) is carried out at the end of the bending step of said first wing (3) against said second wing (4). 8) Method according to claim 6, characterized in that the pressure of the first wing (3) against the second wing (4) is carried out before folding the first wing (3) together with the second wing (4) against the product (1 ). 9) Method according to claim 1, characterized in that the step of partially wrapping a sheet (2) of wrapping around a respective product (1) is carried out: advancing a seat (13) along a predetermined path (14) and in a direction (F2) of predetermined advancement; arranging the wrapping sheet (2) facing said seat (13) and parallel to said predetermined path (14); pushing the product (1) against the wrapping sheet (2) and inside the seat (13); retaining edges of the wrapping sheet (2) against supporting surfaces (22) close to the seat (13) and substantially parallel to said predetermined path (14), said edges defining the first wing (3) and the second wing (4) arranged on opposite bands with respect to the free surface (5) of the product (1) and protruding from said seat (13). 10) Method according to claim 1, characterized in that the step of folding only the first wing (3) in a predetermined direction (FI) towards the surface (5) of the product (1) and against the second wing (4) is implemented by intercepting the first wing (3) by means of a fixed abutment (23) mounted next to said predetermined path (14) and placed near the supporting surfaces (22). 11) Method according to claim 1, characterized in that the step of folding together the first wing (3) and the second wing (4) in said predetermined direction (FI) and against the product (1) is carried out by pushing the product ( 1) out of the seat (13) and intercepting the area (7) of mutual contact of the first and second wing (3, 4) with a bender (45). 12) Method according to claim 1, characterized in that the product (1) is held in the seat (13) by means of a main gripper (18); gripping end (17) of the main gripper (18) delimiting said seat (13) and engaging against portions of the wrapping sheet (2) associated with the product (1). 13) Method according to claim 12, characterized in that the step of folding together the first wing (3) and the second wing (4) in said predetermined direction (F2) and against the product (1) is carried out by holding the product ( 1) with an auxiliary pliers (40); opening the main gripper (18) and intercepting the reciprocal contact area (7) of the first and second wings (3, 4) with a movable bender (42). 14) Method according to claim 9, characterized by the fact that the first and second wings (3, 4) are joined by cold glue and pressed against each other by means of a pair of pressers (32, 33) acting on opposite sides of the zone (7) of mutual contact of the first and second wing (3, 4). 15) Method according to claim 9, characterized in that the first and second wings (3, 4) are joined by cold glue and pressed against each other by pressing the reciprocal contact area (7) against one of the surfaces (22) supported by a presser (34). 16) Method according to claim 1, characterized in that the longitudinal ends (9) of the tubular wrapping (8) are sealed. 17) Method according to claim 1, characterized in that the closure of the longitudinal ends (9) of the tubular wrapping (8) is performed with cold glue. 18) Method according to claim 1, characterized in that it also comprises the step of forming staple knots (10) at the longitudinal ends (9) of the tubular wrapping (8). 19) Device for wrapping products, characterized in that it comprises a conveyor (12) having a plurality of seats (13) placed in succession and advancing along a predetermined path (14) and in a predetermined direction (FI), each seat (13) being adapted to receive a product (1) partially wrapped in a wrapping sheet (2) with a first wing (3) and a second wing (4) protruding from said seat (13); a fixed abutment (23) mounted close to said predetermined path (14) to intercept in succession the wings (3, 4) of each wrapping sheet (2) and cause the first wing (3) to fold in one direction (FI) predetermined, opposite the direction (F2) of advancement, towards a free surface (5) of the product (1) and against the second wing (4); a folding station (39) installed along said predetermined path (14) downstream of the fixed abutment (23), with respect to the predetermined feed direction (F2), to fold the first wing (3) together with the second wing (4) into said sense (FI) predetermined and against the product (1); means for closing the longitudinal ends (9) of the tubular wrapping (8). 20) Device according to claim 19, characterized in that the conveyor (12) has support surfaces (22) interposed between the seats (13) and substantially parallel to the predetermined path (14); both wings (3, 4) protruding from each product (1) lying at least partially in contact with said supporting surfaces (22) before reaching the fixed abutment (23). 21) Device according to claim 20, characterized in that each of the seats (13) is defined by end (17) for gripping a respective main gripper (18) and that the supporting surfaces (22) are defined by terminal portions of the pliers (18). 22) Device according to claim 20, characterized in that each of the seats (13) is defined by a respective pocket (19) and that the supporting surfaces (22) are defined by portions of the conveyor (12) interposed between the pockets ( 19). 23) Device according to claim 19, characterized by the fact that the conveyor (12) is a rotating wrapping wheel, so as to give the predetermined path (14) a shape of an arc of a circle, and that the fixed abutment (23) has a curved surface (24) facing said wrapping wheel (12). 24) Device according to claim 19, characterized in that it further comprises a sealing station (31) positioned along the predetermined path (14) between the fixed abutment (23) and the bending station (39). 25) Device according to claim 21, characterized in that it further comprises a sealing station (31) placed along the predetermined path (14) between the fixed abutment (23) and the bending station (39) and that said station ( 31) for sealing comprises a pair of pressers (32, 33) moving towards or away from each other along a direction transversal to said predetermined path (14) and acting on opposite sides of the area (7) of mutual contact of the first and second wing (3, 4). 26) Device according to claim 22, characterized in that it further comprises a sealing station (31) positioned along the predetermined path (14) between the fixed abutment (23) and the folding station (39) and that said station (31) ) for sealing comprises a presser (34) associated with the support surfaces (22), for pressing the reciprocal contact area (7) against one of said support surfaces (22). 27) Device according to claim 21, characterized in that the folding station (39) comprises an auxiliary gripper (40) for holding the product (1) released by the main gripper (18) and a folder (42) movable along a direction transversal to said predetermined path (14) which can be inserted between the open gripping ends (17) of said main gripper (18), to intercept the mutual contact area (7) of the first and second wings (3, 4). 28) Device according to claim 21, characterized in that the folding station (39) comprises a pusher (44) sliding in the pocket (19) to push the product (1) out of said pocket (19) and a folder (45 ) placed outside said pocket (19), to intercept the mutual contact area (7) of the first and second wing (3, 4).