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Title:
CUTTING AND HEMMING HEAD FOR THE PRODUCTION OF AN EXTENSIBLE FILM CONSTITUTED BY HEMMED STRIPS
Document Type and Number:
WIPO Patent Application WO/2015/033369
Kind Code:
A1
Abstract:
The present invention relates to a cutting and hemming head for the production of an extensible film for packaging that, during production, is divided into longitudinal strips that are subjected to hemming prior to being wound on the respective gathering reel. Provided according to the invention is an apparatus for the production of an extensible film (F) constituted by hemmed longitudinal strips, which envisages a cutting and hemming head (T) comprising: first means (1, 2) for cutting the film into longitudinal strips that are interchangeable while work is in progress, as well as second, preferably adjustable, means (3) for hemming in the desired way said longitudinal strips prior to their passage into the oscillator for being then wound on a respective gathering reel; wherein said adjustable hemming means (3) are designed to provide a centring that is always correct even in the case of variation of the width of the strips.

Inventors:
GAREGNANI ANTONIO (IT)
Application Number:
PCT/IT2014/000237
Publication Date:
March 12, 2015
Filing Date:
September 08, 2014
Export Citation:
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Assignee:
AKRO FLEX S A S DI GAREGNANI ANTONIO & C (IT)
International Classes:
B65H35/02; B65H45/08; B65H45/22; B65H45/28
Domestic Patent References:
WO2002094674A12002-11-28
Attorney, Agent or Firm:
SARPI, Maurizio (Via Collina 36, Rome, IT)
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Claims:
CLAIMS

1. An apparatus for the production of an extensible film (F) constituted by hemmed longitudinal strips, characterized in that it envisages a cutting and hemming head (T) comprising:

- first means (1, 2) for cutting the film into longitudinal strips interchangeable while work is in progress; and

- second, preferably adjustable, means (3) for hemming in the desired way said longitudinal strips prior to their passage into the oscillator for being then wound on a respective gathering reel;

wherein said adjustable hemming means (3) provide a centring that is always correct even in the case of variation of the width of the strips.

2. The apparatus according to the preceding claim, characterized in that said cutting and hemming head (T) envisages at least one first knife (1) for cutting the film longitudinally, downstream of which and in a position corresponding to which there is set a hemming element (3) having an elongated body the width and transverse position of which is such as to come into contact with the side edge of the strip of film just cut to deform it, thus creating a longitudinal reinforcement hem on the strip of film itself.

3. The apparatus according to the preceding claim, characterized in that, in order to stabilize the hem, the strips of hemmed film pass under a pressure roller.

4. The apparatus according to Claim 2 , characterized in that provided upstream of the first knife (1) is a second knife (2) , which normally does not work, being designed to be used instead of the first knife (1) only when the latter has to be replaced for maintenance or for other reasons; said second knife (2) being aligned to the first knife (1) .

5. The apparatus according to Claim 2 or Claim 4, characterized in that said hemming element (3) is equipped with adjustment means (4) designed to modify the transverse position thereof with respect to the strips of film cut to vary the extent of the hem that is made on the cut film; thus obtaining the possibility of increasing/reducing the hem without having to stop the machine and without having to replace the hemmer.

6. The apparatus according to the preceding claim, characterized in that to adjust the position of the hemmer (3) with respect to the film (F) cut in strips to be hemmed, provided in the head (T) are appropriate adjustment means (7) that block the rear part of the hemmer on the head itself.

7. The apparatus according to any one of the preceding claims, characterized in that to adjust the position of the first knife (1) with respect to the film (F) to be cut into strips, provided in the head (T) are appropriate adjustment means (5) that block the rear part of the knife on the head itself.

8. The apparatus according to Claims 4 and 7, characterized in that to adjust the position of the second knife (2) with respect to the film to be cut into strips .further adjustment means (6) are provided for keeping the second knife (2) blocked in the desired position.

9. The apparatus according to any one of Claims

5 to 8 , characterized in that said means for adjusting the width and the position of the hemmer, as well as the position of the knives, are of the, preferably micrometric, screw type.

10. The apparatus according to Claim 2, characterized in that the elongated body of the hemming element (3) is divided longitudinally into two parts, the transverse position of which is adjustable to be able to modify the extent of the hem that is applied to the strips of film just cut.

11. The apparatus according to any one of the preceding claims, characterized in that said hemming means (3) are designed to apply an albeit minimal hem also to the side selvedge scrap, thus obtaining that the pressure roller that is set downstream of the cutting and hemming station is able to draw also said selvedge together with the strips of film.

12. The apparatus according to any one of the preceding claims, characterized in that the hemming means are positioned in the traditional gathering area and in that a further non-motor-driven oscillating roller is provided for facilitating passage from simple film to hemmed film, and vice versa.

13. The apparatus according to any one of the preceding claims, characterized in that said knives are of a rotary-blade type.

Description:
CUTTING AND HEMMING HEAD FOR THE PRODUCTION OF AN

EXTENSIBLE FILM CONSTITUTED BY HEMMED STRIPS

*****

The present invention relates to a cutting and hemming head for the production of an extensible film for packaging that, in the production step, is divided into longitudinal strips that are hemmed prior to being wound on the respective gathering reel .

Known to the art are apparatuses for cutting and hemming extensible films, which present the disadvantage of not enabling easy alignment of the hemming means with respect to the knives, in particular in the case where it is necessary to modify the width of the strips of the film.

Another disadvantage of known apparatuses lies in the fact that hemming is carried out by means of a plurality of disks that need to be replaced or removed in the case where the hem is to be modified or eliminated for creating strips of film with hems that are more or less marked or else absent.

Other known systems envisage the use of supplementary rollers over which the film runs with a part thereof projecting beyond the side of the roller so as to enable creation of the hem. The above known apparatuses require stoppage of the machine for their replacement or removal, or at least require particularly laborious and long operations .

The purpose of the present invention is to overcome the above problems by providing a cutting and hemming head for the production of strips of extensible film that, in addition to being equipped with means for cutting the film into longitudinal strips that are interchangeable while work is in progress, is also equipped with adjustable means for hemming in the desired way said strips prior to their passage into the oscillator for being then wound on the corresponding gathering reel. Said adjustable hemming means enable a centring to be obtained that is always correct even in the case of variation of the width of the strips.

A better understanding of the invention will be obtained from the ensuing detailed description and with reference to the annexed plates of drawings, which illustrate, merely by way of non-limiting example, a preferred embodiment .

In the plates of drawings :

Figure 1 is a side elevation of said cutting and hemming head according to the invention; Figure 2 is a top plan view of the cutting and hemming head of Figure 1;

Figure 3 is a side elevation of just the hemming element taken down from the cutting and hemming head;

Figure 4 is a side view that shows the cutting and hemming head installed in an apparatus for the production of hemmed strips starting from a film;

Figure 5 is a top plan view that shows an example of four cutting and hemming heads set in an apparatus like the one illustrated in Figure 4; and

Figure 6, similar to the previous one, shows the roller over which the film to be divided into hemmed strips passes.

According to the present invention, the cutting and hemming head T envisages at least one first knife 1 for cutting the film F longitudinally, downstream of which and in a position corresponding to which there is set a hemming element 3 having an elongated body the width and transverse position of which is such as to come into contact with the side edge of the film just cut to deform it to create a longitudinal reinforcement hem on the film itself. It is preferable for the hemmed film F to pass under a pressure roller to stabilize the hem. According to a preferred embodiment of the cutting head T, upstream of the first knife 1 a second knife 2 is provided, which normally does not work, being designed to be used instead of the first knife 1, only when the latter has to be replaced for maintenance operation or for some other reason. In this way, advantageously, the first knife 1 can be replaced, sharpened, or maintained, without it being necessary to interrupt operation of the machine on which the cutting and hemming head T is installed.

According to a further peculiar characteristic of the present invention, said hemming element 3 is equipped with adjustment means 4 designed to modify the transverse position thereof with respect to the cut film to vary the extent of the hem that is created on the cut film. In this way, it is advantageously possible to increase/reduce the hem without having to stop the machine and without having to replace the hemmer. Also provided are means 7 for adjusting the position of the hemmer 3 with respect to the strips of film F to be hemmed.

To adjust the position of the first knife 1 with respect to the film F to be cut, provided in the head T are appropriate adjustment means 5 that block the rear part of the knife on the head itself. Similar adjustment means 6 are provided for keeping the second knife 2 blocked in the desired position.

The means for adjustment of the width of the hemmer and of the position of the knives, as well as of the position of the hemmer itself, are preferably of the screw type.

From experimental tests, is has been found that, with the configuration described so far, it is possible to make hems on films with high extensibility of any thickness, even just 7 μιη. In actual fact, the limit is determined by the minimum thickness of the extruded film.

The film that is processed via the head T according to the invention may be of an extensible type, but even with zero or low extensibility.

In the preferred embodiment shown in the figures, the elongated body of the hemming element 3 is divided longitudinally into two parts, the transverse position of which is adjustable to be able to modify the extent of the hem that is applied on the strips of film just cut .

In this , connection, it should be noted that it is preferable to apply an albeit minimal hem also to the side selvedge scrap: in this way, in fact, the pressure roller that is set downstream of the cutting and hemming station is able to draw also said selvedge together with the strips of film. This arrangement advantageously enables use of the mouths for suction of the selvedge with which the machine is equipped, which are set far away from the cutting and hemming station, thus simplifying the modifications to be made to the structure of the machine on which the cutting and hemming heads according to the present invention are installed.

Finally, it should be noted that by positioning - where possible - the hemmers in the traditional gathering area and adding a simple, non-motor-driven, oscillating roller, passage from a simple film to a hemmed film and vice versa is facilitated further.

The present invention has been described and illustrated in a preferred embodiment thereof, but it is clear that modifications and/or equivalent replacements may be made by any person skilled in the branch, without thereby departing from the sphere of protection of the present industrial patent right.

For example, the present invention may be applied, without any substantial modifications, also in the case where the knives are of a rotary-blade type.