FIELD OF THE INVENTION

The present invention concerns a machine and a method to make a tubular product which can be used, in particular, but not only, to produce straws for drinking a liquid or semi-liquid product, by helically winding on a forming mandrel one or more strip-shaped elements, preferably made of paper or other similar materials, or its derivatives, on at least one of which an adhesive substance, for example a glue, has been deposited.

BACKGROUND OF THE INVENTION

The use of straws for drinking dates back to thousands of years ago, although their popularity has become more widespread since the last century, thanks to the use of straw and the industrialization of their production.

Before the advent and the enormous use of plastic materials, with which drinking straws are still produced, there was a period in which straws were produced with paper, although production with the latter material created problems of cost, consistency, stiffness, creasing, or collapse of the straws.

In order to try to reduce environmental pollution, many countries have the objective of limiting, if not eliminating, where possible, the use of plastic materials, therefore there is currently a strong need to return to producing straws, including those for drinking, using paper as a raw material.

Machines and methods for the automated production of tubular products are already known, using paper as raw material, from which drinking straws are then obtained.

In particular, some of these methods known in the state of the art are based on the helical winding of one or more strip-shaped elements, such as paper strips or filaments. This manufacturing technique, known to the people of skill in the art by the English term “filament winding”, can be used to manufacture cylindrical bodies, for example tubular, by helically winding one or more strip-shaped elements made of paper under tension around a cylindrical forming pin, or mandrel, after having deposited or spread one or more layers of glue on at least one surface of the one or more strip- shaped elements.

Examples of such known machines are described in patent application IT 102020000011344 filed by the Applicant.

The disposition of the glue on the strip-shaped elements constitutes a delicate operation since it plays an important role for the structural stability of the tubular products themselves and therefore of the straws, also considering that the thickness of each strip-shaped element with which the latter are formed is very thin, in the range of tenths of a millimeter or, at times, even hundredths of a millimeter.

In fact, if the glue did not guarantee adequate resistance, the tubular products and therefore the straws could collapse, due to the fact that the strip-shaped elements could separate from each other, and/or that each helically wound stripshaped element could become unstuck.

Furthermore, an excessive quantity of glue could lead to the production of tubular products and therefore straws that are not sufficiently rigid, which could bend or sag in an undesirable way, an effect that can be even more evident when the straw is immersed in the liquid to be sipped.

Moreover, for hygienic reasons, the glue must absolutely not come into contact with the liquid or semi-liquid product that passes through the straw, in order to prevent part of the glue from being accidentally ingested by the user.

In order to try to solve these problems, some solutions known in the state of the art have introduced means for drying the glue, for example comprising gas burners or heaters with infrared rays. Some of these solutions are described, for example, in patent documents EP 1.080.874 Al, JP 2002028995 A, US 2.931.278 A and US 2.935.003 A.

One disadvantage of these solutions is that the presence of the drying means in some cases significantly increases the overall sizes of the machine, or, in other cases, it does not guarantee an effective drying action, for example because the drying means act on a very short segment of the path of the strip-shaped elements, or they are disposed too close to the forming mandrel so that the glue does not have sufficient time to dry.

There is therefore a need to perfect a machine and a method to make a tubular product, preferably made of paper, which can be used in particular, but not only, to produce straws, which can overcome at least one of the disadvantages of the state of the art. One purpose of the present invention is to provide a machine and to perfect a method to make tubular products, preferably made of paper or similar materials, or its derivatives, which are provided with high stiffness and therefore have an adequate structural stability.

Another purpose of the present invention is to provide a machine and to perfect a method to make tubular products, preferably made of paper or similar materials, or its derivatives, which are durable over time, which do not bend and/or to sag in an undesirable way even when immersed in a liquid or semiliquid product.

Another purpose of the present invention is to provide a machine and to perfect a method to make tubular products, preferably made of paper or similar materials, or its derivatives, which allow to optimize the consumption of adhesive substance applied onto the strip-shaped elements without compromising the degree of adhesion of a single strip-shaped element, or between the different helically wound strip-shaped elements.

Another purpose of the present invention is to provide a machine and to perfect a method to make tubular products, preferably made of paper or similar materials, or its derivatives, which allow to reach high productivity while maintaining a high quality of the products made.

Another purpose of the present invention is to provide a machine to make tubular products, preferably made of paper or similar materials, or its derivatives, the overall size of which is reduced to a minimum.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes, a machine according to the present invention to make a tubular product, using one or more strip-shaped elements, preferably made of paper or similar materials, or materials derived therefrom, comprises delivery means configured to selectively deliver on at least one surface of at least one of the one or more strip-shaped elements an adhesive substance containing at least a liquid solvent, and forming means configured to form the tubular product by winding the one or more strip-shaped elements in a helical manner and simultaneously gluing them, by means of the adhesive substance.

In accordance with one characteristic aspect of the present invention, the machine also comprises an evaporation path disposed between the delivery means and the forming means, having two substantially vertical segments distanced from each other. The machine also comprises evaporation means disposed on at least one of the two vertical segments, between the delivery means and the forming means as above, in order to selectively remove, by evaporation, at least a part of the liquid solvent contained in the adhesive substance present on at least one of the one or more strip-shaped elements before the latter cooperate with the forming means.

In accordance with another characteristic aspect of the present invention, the two substantially vertical segments as above are joined by a connection segment, which can be curved, or rectilinear or mixtilinear, which develops substantially horizontally or along a slightly inclined directrix.

In accordance with another characteristic aspect of the present invention, the two substantially vertical segments are parallel to each other.

In accordance with another characteristic aspect of the present invention, a first substantially vertical segment of the two substantially vertical segments is disposed adjacent to the delivery means, downstream thereof, while a second substantially vertical segment of the two substantially vertical segments is disposed adjacent to the forming means, upstream thereof.

In accordance with another characteristic aspect of the present invention, the evaporation means as above comprise heating means configured to heat the adhesive substance by irradiation.

In accordance with another characteristic aspect of the present invention, the heating means as above comprise one or more electric resistances, or lamps, which can be selectively activated and are configured to be selectively taken into contact with, or in the proximity of, the one or more strip-shaped elements.

In accordance with another characteristic aspect of the present invention, the evaporation means as above comprise, autonomously, or in combination with each other, means for emitting electromagnetic waves, preferably microwaves; means for emitting rays having wavelengths that fall within the infrared spectrum; means that implement a laser technology, preferably at low power; pressure means configured to carry out the evaporation of the liquid solvent by means of a positive or negative pressure variation.

In accordance with another characteristic aspect of the present invention, the evaporation means as above are contained in an evaporation unit having a substantially vertical development along at least one of the two substantially vertical segments, which is disposed substantially above the delivery means.

In accordance with another characteristic aspect of the present invention, the machine also comprises a feed unit disposed upstream of the delivery means and configured to selectively feed the strip-shaped elements toward the forming means. Furthermore, the machine comprises first guide means to guide the stripshaped elements between the feed means and the forming means, selectively passing through the delivery means, in a first substantially horizontal direction. Furthermore, the machine comprises second guide means to guide the stripshaped elements between the delivery means and the forming means, in a second substantially vertical direction parallel to the two vertical segments. Finally, the evaporation means as above develop substantially vertically and are associated with the second guide means so that the latter are interposed between the two substantially vertical segments.

In accordance with another characteristic aspect of the present invention, there are three strip-shaped elements and the delivery means are configured to selectively deliver the adhesive substance only on a first strip-shaped element and on a second strip-shaped element, so that only the first strip-shaped element and the second strip-shaped element are configured to cooperate with the evaporation means, while a third strip-shaped element is configured to move directly toward the forming means, preferably by-passing the delivery means and the evaporation path.

In accordance with another characteristic aspect of the present invention, a method to make tubular products using one or more strip-shaped elements, preferably made of paper or similar materials, or materials derived therefrom, comprises a delivery step, in which delivery means selectively deliver on at least one surface of at least one of the strip-shaped elements an adhesive substance containing at least a liquid solvent, and a forming step, in which forming means form the tubular product by winding the strip-shaped elements in a helical manner and simultaneously gluing them, by means of the adhesive substance. The method also comprises an evaporation step in which it is provided that the strip-shaped elements follow an evaporation path comprising two substantially vertical segments, distanced from each other, disposed between the delivery means and the forming means, and having, positioned on at least one of the two vertical segments, evaporation means that selectively remove, by evaporation, at least a part of the liquid solvent contained in the adhesive substance present on at least one of the strip-shaped elements before the strip-shaped elements cooperate with the forming means.

In accordance with another characteristic aspect of the present invention, the evaporation means as above are contained in an evaporation unit and during the evaporation step the strip-shaped elements pass through the interior of the evaporation unit advancing along the evaporation path which is disposed substantially above the delivery means.

In accordance with another characteristic aspect of the present invention, there are three strip-shaped elements and during the delivery step the delivery means selectively deliver the adhesive substance only on a first strip-shaped element and/or on a second strip-shaped element, so that only the first strip-shaped element and/or the second strip-shaped element then cooperate with the evaporation means during the evaporation step.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a partial and schematic front view of a machine to make tubular products according to the present invention;

- fig. 2 is an enlarged detail of a portion of the machine of fig. 1 ;

- fig. 3 is an enlarged and schematic cross-section taken along line III-III of fig. 2. We must clarify that in the present description and in the claims the terms vertical, horizontal, lower, upper, right, left, high, low, front and rear, with their declinations, have the sole function of better illustrating the present invention with reference to the drawings and must not be in any way used to limit the scope of the invention itself, or the field of protection defined by the attached claims. For example, with the term vertical our aim is to indicate an axis, or a plane, that can be either perpendicular to the line of the horizon, or inclined, even by several degrees, for example up to 20°, with respect to such perpendicular position.

Furthermore, the person of skill in the art will recognize that certain sizes or characteristics in the drawings may have been enlarged, deformed, or shown in an unconventional or non-proportional way in order to provide a version of the present invention that is easier to understand. When sizes and/or values are specified in the following description, the sizes and/or values are provided for illustrative purposes only and must not be construed as limiting the scope of protection of the present invention, unless these sizes and/or values are present in the attached claims.

DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

First of all, we will now describe one example of an embodiment of the invention, with reference to the attached drawings. This example embodiment is provided by way of illustration of the invention and is not intended as a limitation thereof.

Fig. 1 shows a schematic diagram of a machine 10 according to the present invention for the automated production of tubular products A, preferably made of paper or similar materials, or materials derived therefrom, also suitable to form straws, then cutting each tubular product A to size, in any known manner whatsoever.

As will be explained in greater detail below, the tubular products A are formed by helically winding, for example in the sense of rotation indicated by the arrow R, one or more strip-shaped elements, or strips, collectively indicated by the letter B. In the specific example shown here, the machine 10 allows to make tubular elements A by winding three different strip-shaped elements (figs. 1, 2 and 3), that is, from bottom to top in the drawings, a first strip-shaped element Bl, a second element strip-shaped element B2 and a third strip-shaped element B3.

Other embodiments according to the present invention can provide to use a single strip-shaped element, or two, or more than three strip-shaped elements B.

Purely by way of example and to better frame one of the possible fields of application of the present invention, each tubular product A can have an external diameter comprised between about 2 mm and about 20 mm, preferably between about 4 mm and about 10 mm, and a thickness of the tubular wall comprised between about 0.2 mm and about 0.5 mm. Downstream of the machine 10, the tubular product A can then be cut in order to form straws each having, for example, a longitudinal length comprised between about 50 mm and about 200 mm.

The machine 10 essentially comprises a feed unit 11 (fig. 1), configured to rotatably support three reels 12, 13 and 14, each of which is formed with a corresponding strip-shaped element Bl, B2 and B3 respectively wound in a spiral, and a forming unit 15, disposed downstream of the feed unit 11 and configured to form the tubular product A by suitably winding, in a helical manner, the three strip-shaped elements B onto forming means 16 (figs. 2 and 3), which in this specific case comprise a pin, or mandrel 17, disposed along a longitudinal axis X, for example horizontal. The forming unit 15 can be of any known type whatsoever, for example of the type described in patent application IT102020000011344 filed by the Applicant, or one which will be developed in the future.

First guide means 18 (fig. 1), for example consisting of a plurality of first rollers, are disposed between the reels 12, 13 and 14 to guide the three stripshaped elements Bl, B2 and B3 in a suitable manner between the feed unit 11 and the forming unit 15 in a first substantially horizontal direction.

Between the feed unit 11 and the forming unit 15 there is a delivery unit 19, which comprises delivery means 20, which are configured to selectively deliver an adhesive substance S (fig. 3), for example a glue containing a liquid solvent, for example water, on at least one surface of the one or more strip-shaped elements B, for example in the manner that will be described in detail below. The delivery unit 19 and the delivery means 20 can also be of any known type whatsoever, or one that will be developed in the future. For example, the delivery means 20 can consist of glue dispensers readily available on the market.

According to the embodiment of the present invention shown here, the adhesive substance S is deposited by the delivery means 20 both on a single surface of the first strip-shaped element Bl (fig. 3), preferably on the one which is not intended to touch the pin 17, and also on a single surface of the second strip-shaped element B2, preferably on the one that does not face the first stripshaped element Bl during the winding onto the pin 17. On the other hand, no adhesive substance is deposited on the third strip-shaped element B3, therefore it may not pass through the delivery unit 19, for example passing behind it, and go directly from the reel 14 to the forming unit 15.

Indicatively, the thickness of the adhesive substance S deposited on each stripshaped element Bl and B2 is of the order of micrometers, for example from about 10 pm to about 50 pm. In fig. 3, the thickness of the adhesive substance S is shown enlarged and not to scale, simply for the purpose of illustrating its position.

Other embodiments, not described in detail here, but easily understood by the person of skill in the art, can provide that the adhesive substance S is deposited on the surfaces of the three strip-shaped elements B in a different manner from that described above, provided that the surface intended to touch the pin 17, and the outermost surface of the third strip-shaped element B3, which will then become respectively the internal and external surfaces of the tubular product A, are free of adhesive substance S.

In one embodiment of the tubular elements A, in which it is provided to use a single strip-shaped element, the adhesive substance S will be deposited only on a first zone adjacent to a first lateral edge of the same strip- shaped element, so that then, during the winding onto the pin 17, such first zone is surmounted by a corresponding second zone, free of adhesive substance, adjacent to a second lateral edge, opposite the first, of the same strip-shaped element.

Some embodiments of the present invention can provide that all the stripshaped elements B pass in the delivery unit 19 and that only the delivery means 20 which affect the strip-shaped elements, for example Bl and B2, on which to deposit the adhesive substance S, are activated, while those corresponding to the strip-shaped element on which the adhesive substance must not be deposited, for example B3, are left inactive.

According to one characteristic aspect of the present invention, between the delivery unit 19 and the forming unit 15, in order to reduce the space between the delivery unit 19 and the forming unit 15 and speed up the production process of the tubular elements A, there is an evaporation unit 22 (fig. 1), which comprises evaporation means 23, which are configured to selectively remove in a controlled manner, advantageously by evaporation, at least a part of the liquid solvent contained in the adhesive substance S just deposited on one or more of the three strip-shaped elements B.

In other words, an evaporation path P is defined, disposed between the delivery means 20 and the forming means 16 so that the strip-shaped elements B come into contact with the pin 17 after the adhesive substance S has conveniently dried, in order to not overflow from the same strip-shaped elements B and to make the latter adhere to each other well and quickly.

The evaporation means 23 can comprise, for example, heating means which are configured to heat by irradiation, that is, by Joule effect, the adhesive substance S just deposited by the delivery means on one or more of the stripshaped elements Bl, B2 and/or B3.

The heating means as above comprise, for example, one or more electric resistances, which can be activated selectively and configured to be selectively taken into contact with, or in the proximity of, the strip-shaped elements Bl, B2 and/or B3, and/or also heating lamps, for example infrared.

In particular, each strip-shaped element Bl, B2 and/or B3 on which the adhesive substance S is deposited is guided along the evaporation path P by second guide means 25, consisting for example of second rollers. Furthermore, each strip-shaped element Bl and B2 is suitably guided so that only its surface without adhesive substance S comes into contact with the guide means 18 and 25, with suitable loop means between one roller and the next, where required.

Some embodiments of the present invention provide that the evaporation means 23 can comprise, autonomously or in combination with each other, means for emitting electromagnetic waves, preferably micro waves; means for emitting rays having wavelengths that fall within the infrared spectrum; means that implement a laser technology, preferably at low power; pressure means configured to carry out the evaporation of the liquid solvent by means of a positive or negative pressure variation.

In the embodiment shown here, the evaporation unit 22 has an oblong shape and develops prevalently in a vertical sense. As an indication, its height is preferably comprised between 0.5 m and 2 m, in order to allow an adequate evaporation of the liquid solvent of the adhesive substance S, also taking into consideration the speed of the strip-shaped elements B, which can be high, for example of the order of a few meters per second, in particular up to 4 m/s.

In the example provided here, the evaporation path P comprises two substantially vertical segments Pl, P2, distanced and parallel to each other and joined by a connection segment PC. The evaporation means 23 are positioned on at least one of the vertical segments as above, in this specific case on the segment Pl which is disposed above the delivery unit 19. The second guide means 25 are disposed so as to guide the strip-shaped elements B in the evaporation path P, first along the first segment Pl, then along the connection segment PC, and finally along the second segment P2, being in fact interposed between the two segments Pl and P2.

The substantially vertical disposition of the evaporation unit 22 also allows to reduce the length of the machine 10 as a whole, because the distance between the delivery unit 19 and the forming unit 15, and therefore the distance between the feed unit 11 and the latter, is reduced to a minimum.

This advantageous technical effect is achieved also thanks to the fact that the evaporation path P develops substantially vertically. Furthermore, the presence of the two segments Pl and P2 allows to double the extension of the evaporation path, so as to guarantee an effective action of evaporation of the liquid solvent contained in the adhesive substance, before the strip-shaped elements cooperate with the forming means 16. The vertical disposition of the two segments Pl and P2 means that the machine 10 is equipped with an evaporation path P significantly longer than those present in the solutions known in the state of the art, while remaining compact, without a significant increase in its overall sizes.

The machine 10 also comprises a central control unit, which can be of any known type whatsoever or one that will be developed in the future, and which is not shown here, which is configured to control the functioning of the forming means 16, of the delivery means 19 and of the evaporation means 23.

The functioning of the machine 10 described so far, which also corresponds to the method to make tubular products A in an automated manner, preferably made of paper or of similar materials, or materials derived therefrom, according to the present invention, occurs entirely in an automated manner under the control of the central control unit as above.

Essentially, the method as above comprises a dragging step in which the stripshaped elements Bl, B2, B3 are dragged directly by the forming means 16 which cause them to suitably unwind from the respective reels 12, 13 and 14, and make each strip-shaped element on which to deposit the adhesive substance S, that is, in the example provided here the first strip-shaped element Bl and the second strip-shaped element B2, pass first through the delivery unit 19 and then through the evaporation unit 22, while the third strip-shaped element B3 on which the adhesive substance S must not be deposited by-passes the delivery unit 19 and the evaporation unit 22.

At the same time as the dragging step, a delivery step takes place in the delivery unit 19, in which the delivery means 20 deposit the adhesive substance S on the strip-shaped elements Bl and B2, such delivery step being immediately followed by an evaporation step in the evaporation unit 22, in which the evaporation means 23 make at least a part of the liquid solvent contained in the adhesive substance S just deposited on the same strip-shaped elements Bl and B2 evaporate. In the evaporation step, it is provided that the strip-shaped elements follow the evaporation path P, comprising the two substantially vertical segments Pl and P2.

A forming step then follows, in which the three strip-shaped elements Bl, B2 and B3 are helically wound onto the pin 17 (figs. 2 and 3), and are simultaneously glued to each other by means of the adhesive substance S interposed between them.

Therefore, based on the above disclosure, it is evident that disposing the evaporation means 22 between the means 20 for delivering the adhesive substance S on the strip-shaped elements B and the forming means 16 is very advantageous and allows to obtain surprising results, especially in terms of productivity. It is clear that modifications and/or additions of parts or of steps may be made to the machine 10 and to the corresponding method to make a tubular product, preferably made of paper or similar materials, or materials derived therefrom, as described heretofore, without departing from the field and scope of the present invention as defined by the attached claims. In fact, it is understood that the field of protection of the present invention shall include such modifications and/or additions of parts or steps.

It is also clear that, although the present invention has been described with reference to one specific example of how the present invention can be embodied, a person of skill in the art shall certainly be able to achieve many other equivalent forms of machines and methods, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the reference symbols and numbers in brackets is to facilitate the reading thereof: they must not be considered as restrictive factors with regard to the field of protection defined thereby.