APPARATUS FOR WRAPPING PRODUCTS WITH A FILM MADE OF

EXTENSIBLE MATERIAL

Technical Field

The present invention regards an apparatus for wrapping products with a film made of extensible material.

Background Art

Nowadays it is known the exigency of wrapping groups of products, usually arranged on a pallet, with a film made of extensible material of the type of the polyethylene. Apparatuses able to operate in an automatic or semiautomatic way the wrapping of products with the cited film made of extensible material have thus been developed. Such apparatuses generally provide for a supply unit carrying a spool of film made of extensible material which is borne in relative rotation with respect to the products to be wrapped.

According to a known solution, the products to be wrapped are fed to a rotating table which is suitable to be put in rotation, according to a vertical axis, with respect to the unit for supplying the extensible film, borne by a carriage which in the wrapping phase is mobile along a support column. The rotation of the rotating table determines the wrapping of the extensible film along the lateral surface of the products, while the axial shift of the carriage carrying the spool causes the production of a spiral development of such a wrapping.

An apparatus of this type is illustrated as an example in patent EP 1083126. Such an apparatus comprises a supply unit carrying a spool of film made of extensible material, a rotation device for producing a relative rotation of the supply unit with respect to the products to be wrapped according to the axis of the aforesaid spool.

In a different known solution, the unit for supplying the extensible film is borne by an arm rotating about the products to be wrapped, which have a fixed position during the wrapping phase. The use of an apparatus of this type is preferable for example for wrapping unstable products, with the scope of avoiding the risk of fall during the wrapping phases.

According to a further known solution, the supply unit carrying the spool of film made of extensible material is borne by a ring rotating according to a vertical or alternatively horizontal axis on a fixed structure, at the centre of which are arranged the products to be wrapped. The rotating ring is constrained to a frame mobile according to a direction axial to the same rotating ring. An apparatus of this kind is illustrated for example in patent application EP 1963188.

The apparatuses which are known nowadays do not fully satisfy the exigencies of the users, particularly regarding the limited operating speed produced in the wrapping phase. As a consequence of this, such apparatuses generally have a productivity which is not adapted to the possibilities of the most evolved lines for packaging the products.

Disclosure of invention

The task of the present invention is that of solving the aforementioned problems, devising an apparatus which enables to operate in an optimal manner the wrapping of products with a film made of extensible material, in particular achieving a high productivity.

Within such a task, a further object of the present invention is that of providing an apparatus that allows to operate in an easy way the operations of gripping, cutting and sealing the extensible film. Another object of the present invention is that of providing an apparatus having a simple conception, a securely reliable functioning and versatile use, as well as relatively economic cost.

The above mentioned scopes are attained, according to the present invention, by the apparatus for wrapping products with a film made of extensible material according to the attached claims.

Brief Description of the Drawings

Details of the invention shall be more apparent from the detailed description of a preferred embodiment of the apparatus for wrapping products with a film made of extensible material according to the invention, illustrated for indicative purposes in the attached drawings, wherein:

figure 1 shows a perspective view of the apparatus for wrapping products with a film made of extensible material;

figure 2 shows the same perspective view of the apparatus, in a different operating phase;

figure 3 shows a perspective view thereof from a different angle;

figure 4 shows a detail view of an unit for supplying the extensible film used in the apparatus in hand;

figures 5 and 6 respectively show a front view and a top view of the apparatus. Best Modes of Carrying Out the Invention

With particular reference to such figures, the apparatus for wrapping products with a film made of extensible material, of the polyethylene type, is indicated in its entirety with 1. The apparatus 1 has a bearing structure 2 shaping a kind of portal . At the base of such a bearing structure 2 there are suitable to be prearranged the products to be wrapped, preferably arranged on a pallet support, through known feeding means not represented for simplicity, such as for example a suitably motohsed roller conveyor.

At the top of the bearing structure 2, in a substantially central position, there is arranged a rotation device 3 provided with a motor member 4 which is suitable to put in rotation, according to a vertical axis, a rotating arm 5. The rotating arm 5 supports at one end a column 6 that extends vertically downwards. Along guide means 7 shaped by the column 6 there is guided slidingly a carriage 8 which constitutes part of a shifting device 9 equipped with a relative motor member 10, mounted at the top of the same column 6. The motor member 10 is suitable to control the shift of the carriage 8 along the column 6 through known means for transmitting the motion arranged inside the same column 6.

The carriage 8 of the shifting device 9 supports overhang a supply unit 1 1 carrying a spool 12 of film made of extensible material. The spool 12 is carried rotating, according to a vertical axis, by a support 13 of the supply unit 11 , having a box shape, which is integral to the carriage 8.

According to the present invention, the apparatus comprises an auxiliary supply unit 21 carrying a second spool 22 of the film made of extensible material. The auxiliary supply unit 21 is associated with the supply unit 1 1 on the shifting device 9 and is axially mobile with respect to the same supply unit 1 1 . More particularly, the second spool 22 is borne rotating, according to a vertical axis, by a support 23, having a box shape, which is integral to a second carriage 24 guided slidingly along the column 6 through the cited guide means. The second carriage 24 is mobile with respect to the carriage 8 of the supply unit 11 through the interposition of suitable actuators 25. In the illustrated case, such actuators 25 are constituted by a compensator articulation mechanism actuated by a suitable motor member. Nevertheless it is possible to provide for the use of different actuator means, for example of the pneumatic type, functionally equivalent.

The auxiliary supply unit 21 is axially mobile with respect to the supply unit 11 between a first operating position wherein the second spool 22 is basically placed beside the first spool 12 along the column 6 and a second operating position wherein the same second spool 22 is axially staggered with respect to the spool 12, in a way as to increase, in the wrapping phase, the wideness of the band of extensible material developed around the products.

Moreover, the apparatus is provided with a unit 30 for seizing, cutting and sealing the extensible film, of a known type in the specific sector of use and therefore not described in major detail.

The functioning of the apparatus for wrapping products with a film made of extensible material according to the invention turns out to be easy to understand from the preceding description.

Firstly, it is provided to prearrange the shifting device 9, carrying the supply units 11 , 21 , in the predetermined position for the beginning of the operating cycle, as a function of the dimensions and/or of the shape of the load to be wrapped, for example a group of products arranged in an ordered manner on a pallet. The products to be wrapped are fed in the wrapping post, at the centre of the bearing structure 2, where they are suitable to be associated with a border of the plastic film that unwinds from the spools 13, 23. The rotation of the rotating arm 5, actuated by the motor member 4 of the rotation device 3 determines the wrapping of the extensible film along the lateral surface of the products; the simultaneous axial shift of the carriages 8, 24 carrying the spools 12, 22 causes the production of a spiral development of such a wrapping.

According to the present invention, during the cited wrapping phase the auxiliary supply unit 21 is displaced in the second operating position wherein the second spool 22 is axially staggered with respect to the spool 12, as can be seen in fig. 2. In such a configuration the wideness of the band of extensible material developed around the products is substantially doubled. In other words, at every turn of the rotating arm 5 the surface of the products covered by the extensible film, and accordingly the production speed of the apparatus, are substantially doubled.

The axial displacement of the second spool 22 of the auxiliary supply unit 21 with respect to the first spool 12 is suitably operated at the beginning of every operating cycle. Nevertheless it is possible to provide for it to take place also in a successive moment.

At the end of the products wrapping phase, the second spool 22 is brought back in the initial operating position, substantially placed beside the first spool 12 along the column 6, so as to enable to operate seizing, cutting and sealing of the extensible film by means of a unique device 30.

The apparatus in hand therefore attains the scope of operating in an optimal way the wrapping of products with a film made of extensible material, and in particular reaching a high productivity.

Such a result is obtained essentially thanks to the inventive idea of providing an auxiliary supply unit carrying a second spool of extensible film which is axially mobile with respect to a first spool of extensible film, in a way as to considerably increase, in the wrapping phase, the wideness of the band of extensible material developed around the products and accordingly decrease in proportion the time