WO2023026310A1

WO2023026310A1 - Apparatus and method for making flexible shaped portions on tubular elements

Info

Publication number: WO2023026310A1
Application number: PCT/IT2022/050229
Authority: WO
Inventors: Fabrizio Tale'
Original assignee: I.M.A. Industria Macchine Automatiche S.P.A.
Priority date: 2021-08-23
Filing date: 2022-08-09
Publication date: 2023-03-02
Also published as: IT202100022160A1

Abstract

The apparatus (10) for forming flexible shaped portions (105) on tubular elements (100), preferably made of paper, comprises a unit (11) for conveying the tubular elements (100), configured to convey them along a path of advance (A), and external forming means (20) comprising a first forming unit (21) that has a plurality of forming members (30) which are configured to locally shape the tubular elements (100) so as to form the flexible shaped portions (105).

Description

“APPARATUS AND METHOD FOR MAKING FLEXIBLE SHAPED PORTIONS ON TUBULAR ELEMENTS”

FIELD OF THE INVENTION

The present invention concerns an apparatus and a method for making flexible shaped portions on tubular elements, preferably made of paper, cardboard or other similar materials with adequate flexibility that allows their deformation.

In particular, the apparatus and the method according to the present invention are suitable to work tubular elements from which to obtain straws, for example to be used to drink a liquid or semi-liquid product. More specifically, the flexible shaped portion made on the tubular element allows, during use, to bend the straw in two, in order to reduce its length before it is packaged, and then, also repeatedly, for a user to bend it as desired, without damaging it and maintaining its functionality.

BACKGROUND OF THE INVENTION

Plastic or paper straws are known, typically used in the food sector for sipping drinks or beverages in general from containers, such as glasses, bottles, carton packs, for example in the shape of a parallelepiped, also known as “Briks”.

It is also known that some types of straws are of the bendable type, having a flexible shaped portion, which allows the straw to be bent in two, also repeatedly, without damaging it and maintaining its functionality. Typically, this flexible shaped portion is of the “bellows” type, defined by a succession of annular ridges and grooves coaxial to the longitudinal axis of the straw, and formed for example by grooves, indentations and variations in thickness, suitable to allow it to bend.

These bendable straws are often combined, individually, with hermetically sealed containers of drinks, such as fruit juices or other, which are normally small in size, with a capacity in the order of 100-200 ml, and are each provided with a pierceable zone to facilitate the insertion of the straw.

Apparatuses and methods for making straws provided with a flexible shaped portion are described, for example, in US patent documents US-A-2.985.077, USA-3.493.998 and US-B1-9.974.403.

These known solutions provide mechanical deforming members which act on the straw kept in rotation to form the annular grooves in suitable positions, so that each groove is interposed between two consecutive ridges.

In some known solutions, such as for example in the one described in US-A- 2.985.077 as above, the mechanical deforming members are located on a member rotatable around an axis of rotation parallel to that of the straw being worked, so that their action also causes the straw itself to rotate during the forming of the grooves.

In other known solutions, such as for example in the one described in US-A- 3.493.998 and US-B1-9.974.403 as above, forming mandrels are provided, configured to be inserted inside the straws to be deformed.

In the solution described in document US-B 1-9.974.403, fixed corrugation blades are also provided, which act on the external surface of the straws. The blades are disposed along an arc of a circle in suitable axially staggered positions so that during the rotation movement of the mandrels carrying the straws around a central longitudinal axis, the straws come into contact with a first corrugation blade, then with a second corrugation blade and so on.

These known solutions have various disadvantages, in particular when they are used to make the flexible shaped portion of straws made of paper. In fact, while plastic materials - by virtue of their intrinsic properties - allow to make the grooves and ridges of the flexible shaped portion with relative ease, this is not the case for paper straws. In fact, due to the intrinsic properties of the material, paper has a mechanical resistance to permanent deformation which is much higher than that of plastic materials, following an elastic-plastic behavior. In other words, the paper has a significant elastic component that causes the material to take on its original shape again, when the action of the mechanical deforming members ceases.

Furthermore, another disadvantage of the solutions known in the state of the art is that the mechanical deforming members act on the straw and contact it to deform it only for a very short period of time, for example equal to the time that the straw takes to perform one rotation, or some rotations, on itself.

It is obvious that in this limited period of time the mechanical deforming members are not able to perform a compression/deformation action on the paper such as to create grooves and ridges that then have a stable and long-lasting shape over time.

Consequently, one disadvantage of known solutions is that they do not allow the paper straws to be deformed permanently, since the flexible shaped portion could stretch out immediately after the deformation it has suffered, and thus lose, at least to a significant extent, the previously formed grooves and ridges.

Another disadvantage of known solutions, always linked to the intrinsic properties of paper, is that they are not able to deform the straws in such a way as to obtain a bellows structure provided with clear and defined bends, in order to form the grooves and ridges. This means that these straws are not easy to bend in the bellows zone and also that they are inconvenient to use.

Another disadvantage of some of the apparatuses and methods known in the state of the art is that they allow to produce flexible shaped portions which, although they do allow an end part of the straw to be bent, this is only with wide radii of curvature. Consequently, these solutions prevent the straw from bending substantially on itself, that is, with a bending angle of up to 180°, unless a very long flexible shaped portion is provided which is therefore not compatible with the practical and industrial needs of the field of application described above, for example for small-sized drinking straws, such as straws for small portable containers for drinks, such as those of the “Brik” type.

Another disadvantage of some known solutions is that they are unable to achieve the high productivity values required in industrial sectors of consumer goods with a low unit economic value, such as straws, which makes it uneconomical to use such apparatuses and methods known in the state of the art.

There is therefore a need to perfect an apparatus and method for making flexible shaped portions on tubular elements, which can overcome at least one of the disadvantages of the state of the art.

In order to do this, it is necessary to solve the technical problem of permanently deforming the paper straws so that the flexible shaped portion does not stretch, and maintains the grooves and ridges formed.

One purpose of the present invention is to provide an apparatus and perfect a method for making at least one flexible shaped portion on tubular elements, preferably made of paper or similar materials, from which straws are preferably obtained.

Another purpose of the present invention is to provide an apparatus and perfect a method able to achieve high or very high productivity, understood as the number of shaped tubular elements in the unit of time, even greater than a thousand per minute.

Another purpose of the present invention is to provide an apparatus and perfect a method which are reliable and effective, able to produce shaped portions formed by a succession of annular ridges and grooves coaxial to a longitudinal axis of the tubular elements, substantially defined by clear and permanent bends, and having a stable shape that is maintained indefinitely over time.

Another purpose of the present invention is to provide an apparatus and perfect a method which are very flexible, and which allow to work tubular elements having an overall longitudinal length comprised in a very wide range of values.

Another purpose of the present invention is to provide an apparatus and perfect a method which are suitable to be integrated into a more complex, preferably automated machine, able to perform all the necessary workings on the tubular elements, for example to transform them into finished straws, as well as to pack each of the latter in a corresponding package suitable to preserve it hygienically until it is used.

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 and to resolve the above technical problem in a new and original way, also achieving considerable advantages compared to the state of the prior art, an apparatus is made available for making at least one flexible shaped portion on tubular elements which is defined by a succession of annular ridges and grooves, preferably for making straws, in particular made of paper or similar materials. In particular, the annular ridges and grooves are substantially coaxial to a longitudinal axis of the tubular elements.

Here and throughout the present description, the terms “ridges” and “grooves” refer, respectively, to reliefs and depressions defined for example as grooves, or indentations, or folds, or thickness variations that allow to significantly bend the flexible shaped portion in order to then be able to fold a terminal portion of the tubular elements onto the other portion, which can have a length that is the same as or different to the terminal portion as above, of the tubular elements themselves.

In the present description, the apparatus and the method according to the present invention will be described with reference to the working of a tubular element able to form a straw, to which reference will be made hereafter in an exemplary and non-limiting manner. It is understood that the teachings of the present invention disclose an apparatus and a method suitable to also work other types of tubular products, to work which the person of skill in the art is perfectly capable of adapting the teachings of the present invention to the specific case of application.

In accordance with some embodiments, there is provided an apparatus for making flexible shaped portions on tubular elements, each flexible shaped portion being defined by a succession of annular ridges and grooves substantially coaxial to a first longitudinal axis of each of the tubular elements, so as to obtain at least one straw from each of them. Advantageously, the tubular elements are made of paper or similar material.

The apparatus comprises a unit for conveying the tubular elements, configured to convey the tubular elements along a predetermined path of advance, preferably in an orderly succession.

The apparatus also comprises external forming means configured to locally shape each of the tubular elements by acting on an external surface thereof.

In some embodiments of the present invention, the apparatus optionally also comprises internal forming means, configured to locally shape each of the tubular elements by acting on an external surface thereof, in association with the external forming means as above.

The external forming means comprise a first forming unit, comprising a plurality of forming members configured to act on the tubular elements in order to create the flexible shaped portion.

The plurality of forming members is positioned in such a way as to be moved along a closed loop path. This closed loop path does not intersect the path of advance of the tubular elements at any point, being parallel to a portion of the path of advance for at least one segment.

According to one aspect of the present invention, the forming members are configured as sliders.

According to one aspect of the present invention, the forming members are disposed side by side and are configured to be moved along the closed loop path.

According to one aspect of the present invention, the forming members are mounted on a common conveyor, for example a conveyor belt.

According to one aspect of the present invention, each forming member of the plurality of forming members is driven in order to move autonomously from the remaining others.

The forming members each comprise a respective work surface; the surfaces being configured in such a way as to contribute to form, as a whole, a forming surface of the first forming unit when the forming members are located side by side and in succession.

According to one aspect of the present invention, the first forming unit comprises a plurality of corrugations which define a respective succession of ridges and grooves.

According to one aspect of the present invention, in the embodiments in which the internal forming means are provided, the latter comprise a corrugated portion having a profile formed by a succession of internal annular ridges and grooves which are disposed in a manner that is offset to those respectively of the plurality of corrugations of the first forming unit during the formation of the shaped portion, so that the annular ridges of the internal forming means are aligned with the grooves of the external forming means in order to form the ridges of the shaped portion, while the grooves of the internal forming means are aligned with the ridges of the external forming means in order to form the grooves of the shaped portion.

According to one aspect of the present invention, each forming member comprises a support connected to the common conveyor, a body attached to the support, and a forming element mounted on the body and on which the plurality of corrugations is made.

In accordance with some embodiments of the present invention, the external forming means also comprise a second forming unit, configured to act on the tubular elements in cooperation with the forming unit. The second forming unit is positioned at least partly inside the conveying unit. Preferably, the second forming unit is disposed in such a way as to be completely inscribed within the conveying unit, or more specifically, within the path of advance of the tubular elements.

The second forming unit is disposed in such a way as to define, together with the first forming unit, a zone for forming the flexible shaped portions of the tubular elements.

According to one aspect of the present invention, the second forming unit comprises a respective plurality of corrugations which define a respective succession of ridges and grooves. The first and second forming units are reciprocally opposite each other, with a passage zone in the middle to selectively receive the tubular elements in contact with the respective plurality of corrugations. In some embodiments, during the transit of the tubular elements in the passage zone, the internal forming means are possibly inserted inside them so that the flexible shaped portions are formed by the cooperation of the corrugations present on the first and on the second forming units, together with those present on the internal forming means, if these are present.

Preferably, it is possible to also identify a respective forming surface in the second forming unit, such forming surface being formed by the respective plurality of corrugations.

In a preferred embodiment, the second forming unit, and with it its forming surface, are fixed.

In other embodiments, the second forming unit can be mobile, being conformed as a disc that has its own longitudinal axis of rotation. The latter can be disposed in such a way as to be distanced, for example by one or a few millimeters, but possibly even by a greater distance, of up to fifteen millimeters, with respect to a longitudinal axis of the apparatus, which defines a main axis of work around which the conveying unit can rotate in order to make the tubular elements advance along their path of advance.

In particular, the second forming unit can be mobile in the same sense of movement as the forming surface of the first forming unit, but at a lower speed than the one at which the latter moves. It can also be provided that the forming surface of the second forming unit is mobile in the opposite sense to the sense of advance of the forming surface of the first forming unit.

By movement speed, in the present description we mean the linear speed taken at any point of the respective forming surfaces. In accordance with some embodiments, the second forming unit can have an extension such that it can cooperate with a plurality of conveying units, for example at least nine conveying units in the example provided here, located parallel to each other and in succession along the path of the forming members moved by the common conveyor.

According to other embodiments, also the conveying unit is configured as a conveyor belt provided with a plurality of sliders, which can be similar to the sliders of the first forming unit.

According to another aspect of the present invention, there is also provided a method for making flexible shaped portions on tubular elements, preferably made of paper, wherein each of the flexible shaped portions is defined by a succession of annular ridges and grooves substantially coaxial to the first longitudinal axis of each of the tubular elements.

The method provides a step of conveying, by means of a conveying unit, the tubular elements along a predetermined path of advance. Preferably, the tubular elements are fed in an orderly succession.

The method also provides a forming step, during which external forming means comprising a plurality of forming members act on an external surface of the tubular elements while they advance along the path of advance, in such a way as to form the flexible shaped portions. According to one aspect of the present invention, during this forming step it is provided to move, along a closed loop path which develops for a segment of the path of advance, the plurality of forming members of a first forming unit which is comprised in the external forming means. The method according to the present invention also provides to drive a conveyor into movement, for example a conveyor belt, on which the plurality of forming members is mounted, so as to move the forming members along the closed loop path as above.

According to one aspect of the present invention, the method provides to keep the second forming unit fixed or to move it in a sense that is concordant with the first forming unit, but at a lower speed than the speed of the first forming unit.

According to some embodiments of the method according to the present invention, it is provided to selectively insert, inside the tubular elements, internal forming means configured to locally shape each of the tubular elements in order to create a corresponding flexible shaped portion, by acting on an internal surface of the tubular element, in association with external forming means.

DESCRIPTION OF THE DRAWINGS

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

- fig. 1 is a schematic front view of a working station comprised in a machine for the automated production of straws, comprising an apparatus for making a flexible shaped portion on tubular elements, in accordance with the teachings of the present invention, in which some components have been removed for reasons of clarity;

- fig. 2 is a schematic longitudinal section view of a paper tubular element, deformed using the apparatus of fig. 1;

- fig. 3 is an enlarged and schematic three-dimensional view of some components of the apparatus in fig. 1 in a working step;

- fig. 4 is a partial, schematic and not to scale section of a detail of the apparatus of fig. 1 , which shows a step of working the tubular products;

- fig. 4a is an enlarged detail of fig. 4;

- fig. 5 is a cross section taken along the plane with outline V-V of fig. 1, which shows one of the forming members comprised in the apparatus according to the present invention; and

- figs. 6 and 7 are front and schematic views of additional embodiments of a working station comprised in a machine for the automated production of straws, comprising an apparatus for making a flexible shaped portion on tubular elements, in accordance with the teachings of the present invention.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF SOME EMBODIMENTS

With reference to fig. 1, an illustrated working station comprised in a machine for the automated production of straws starting from already made tubular elements comprises an apparatus 10 for making at least one flexible shaped portion on such tubular elements. The tubular elements, indicated in the drawings with the reference number 100, are preferably made of paper material, and each have a certain initial length L preferably comprised between about 50 mm and about 400 mm (fig. 2).

By way of a non-limiting example, the machine for the automated production of straws can be configured as that described in Italian patent applications n. 102020000013819 or 102020000013822 of the same Applicant, or also as a machine of any other known type whatsoever, or one which will be developed in the future.

In addition to the working station shown, the machine typically comprises a plurality of other stations for working the tubular elements 100, disposed in succession along a path of advance A of the tubular elements 100, a portion of which is shown with a dashed line in fig. 1.

The apparatus 10 for making flexible shaped portions on tubular elements 100 comprises a rotating member 11, to which the tubular elements are fed in correspondence with an inlet station 11 A. The rotating member 11 moves the tubular elements along the portion of the path of advance A mentioned above, up to an outlet station 11B, in correspondence with which the tubular elements 100 leave the rotating member 11 in order to advance toward additional working stations, for example configured to cut an end portion of the tubular elements 100, and/or to fold the two opposite ends of the tubular elements 100 on each other by 180° in order to form a straw 101 folded in correspondence with the flexible shaped portion previously made by means of the apparatus 10 according to the present invention.

To better understand the inventive concept of the present invention, before describing the apparatus 10 and the corresponding method in detail, we will now describe an example of how the flexible shaped portion can be made on a tubular element 100 by using the apparatus 10, it being understood that the present invention is not limited to this example, and that the invention can be used to work many other types of tubular elements, of a type already known.

By way of example, as better shown in fig. 2, the tubular element 100 can be configured as a single hollow tubular body with an oblong shape and a longitudinal axis Z, from which a straw 101 is preferably obtained.

Each tubular element 100 comprises an internal surface 102 and an external surface 103, which define a cylindrical wall having a certain thickness, for example comprised between about 0.2 mm and about 0.5 mm. Purely as an indication, the tubular element 100 can have an external diameter comprised between about 2 mm and about 20 mm, preferably between about 2.5 mm and about 5 mm.

Each tubular element 100, at the end of the method carried out with the apparatus 10, will have a flexible shaped portion 105, in the shape of a bellows, and two end portions 106, 108 between which the flexible shaped portion 105 is interposed. The flexible shaped portion 105 will allow each straw 101 to be folded back on itself even up to about 180°, that is, until its two end portions 106 and 108 are substantially parallel to each other, with a very small radius of curvature.

The flexible shaped portion 105 is defined by a succession of ridges 105a and grooves 105b, annular and coaxial with respect to the longitudinal axis Z of the straw 101, also referred to in the present description as first longitudinal axis Z.

In order to obtain this straw 101, the flexible shaped portion 105 can be advantageously made by means of the apparatus 10 according to the present invention, by means of the method that will be explained in greater detail below.

With reference to fig. 1, we will now describe in greater detail an embodiment of the apparatus 10 in accordance with the teachings of the present invention. The apparatus 10 comprises a rotating member 11, which acts as a unit for conveying the tubular elements 100 from which the straws 101 are obtained, which has its own longitudinal axis X, also called second longitudinal axis, which can for example be oriented horizontally. The rotating member 11 is mounted rotatable around the longitudinal axis X, which constitutes the main axis of the apparatus 10.

The rotating member 11 is made to rotate, for example, by a first electric motor of a known type, which for simplicity is not shown in the drawings, for example by means of a toothed gear, not shown, which moves a central shaft 12 rotating coaxially with respect to the longitudinal axis X. For example, the rotating member 11 is made to rotate in a certain sense of rotation S (fig. 1), which is counterclockwise if viewed from the front of the apparatus 10.

The apparatus 10 can be provided with a plurality of gripping members, not shown in the drawings, that is, with a certain number of individual gripping members that are each one angularly distanced by a certain angular pitch from the adjacent one. For example, if thirty gripping members are provided, the angular pitch can be equal to 12°.

Each gripping member is configured to selectively grip or release a tubular element 100 so as to hold it, in such a way that it is oriented with its longitudinal axis Z parallel to the longitudinal axis X, while it is worked in the apparatus 10, for example for a defined angle of engagement a (fig. 1) corresponding to an analogous angle of rotation of the rotating member 11.

Please note that the gripping members can be of any known type whatsoever, and can be configured, for example, as grippers or jaws, actuated by means of suitable command means capable of selectively and automatically taking them to alternatively assume a closed, or gripping, condition and an open, or releasing, condition, in which they respectively grip and hold in position, or release, a tubular element 100.

In the example provided here, the apparatus 10 comprises a plurality of forming pins 13 (fig. 3) suitably shaped and configured to be selectively and temporarily inserted inside the tubular elements 100, as will be described in detail below. We must clarify, however, that in other embodiments, equally comprised within the scope of the present invention, the apparatus 10 can be without the forming pins 13.

All the forming pins 13 are parallel to the second longitudinal axis X and are angularly distanced from the adjacent one by the angular pitch mentioned above. In this way, the spatial disposition of the forming pins 13 is angularly coordinated with the disposition of the gripping members, so that each tubular element 100 is temporarily and selectively held from the outside by a respective gripping member, and a corresponding forming pin 13 is selectively and temporarily inserted inside it.

With particular reference to figs. 3, 4 and 4a, we will describe in greater detail the structure of each forming pin 13, which comprises a cylindrical stem 13a, preferably metallic, which has an external diameter substantially equal to or slightly smaller than the internal diameter of the tubular elements 100.

On the cylindrical stem 13a there is a corrugated portion 14, which is shaped in such a way as to define a succession of annular ridges 14a and grooves 14b, side by side to each other with a linear pitch P (fig.4a) comprised between a few tenths of a millimeter and a few millimeters, and coaxial to the first longitudinal axis Z. Please note that the first longitudinal axis Z, when the forming pin 13 is inserted inside a respective tubular element 100, coincides with the axis of the forming pin 13, since the latter is coaxial to the tubular element.

In one embodiment, given here by way of example, the corrugated portion 14 comprises a succession of nine ridges 14a and ten grooves 14b, disposed in sequence one after the other according to a disposition whereby a ridge 14a and a groove 14b alternate in succession one after the other.

The different forming pins 13, together with their corrugated portions 14, define internal forming means 15 of the tubular elements 100 which are configured to interact with the internal surface 102 of the latter during the method for making the flexible shaped portion 105 on such elements.

The forming pins 13 are associated with respective actuators, not shown in the drawings, so as to be configured to be displaced axially, with reciprocating motion, parallel to the second longitudinal axis X, between a first operating position, in which they are disposed outside the tubular elements 100, and a second operating position, in which they are inside the tubular elements 100, and vice versa, with a complete cycle for each 360° rotation of the rotating member 11.

The apparatus 10 also comprises external forming means 20 (figs. 1 and 3), configured to cooperate with the internal forming means 15 in order to create the flexible shaped portions 105 (figs. 4 and 4a) on the tubular element 100, as will be described in detail below.

The external forming means 20 substantially comprise a mobile forming unit 21, also called the first forming unit, and a second forming unit 22 disposed coplanar with the first mobile unit 21, and configured to cooperate with the latter and possibly with the forming pins 13, if present, in order to create the flexible shaped portions 105 (fig. 3) on the tubular elements 100, as will be described in detail below. Please note that in other embodiments of the present invention, in which the apparatus 10 is without the forming pins 13, the flexible shaped portions 105 are created only by means of the external forming means 20, thanks to the cooperation of the first and second forming units 21, 22.

The mobile forming unit 21 comprises a forming surface 23 configured to act on a part of the external surface 103 of the tubular elements 100. The mobile forming unit 21 is disposed outside the bulk of the rotating member 11 , so that the forming surface 23 acts on the tubular elements 100 from the outside with respect to the same rotating member 11.

The forming surface 23 is shaped in such a way as to have a plurality of corrugations 25, which comprise ridges 25a and grooves 23b in succession (figs. 3 and 4a), which have the same linear pitch P (fig. 4a) as the ridges 14a and grooves 14b of the corrugated portion 14 of each forming pin 13. In the example given here, the forming surface 23 has ten ridges 25a and nine grooves 25b.

Please note that when each forming pin 13 is in its second operating position, that is, inside one of the tubular elements 100 (figs. 4 and 4a), its ridges 14a and grooves 14b are offset by half of the linear pitch P (fig. 4a), that is, by P/2, with respect to the ridges 25a and grooves 25b of the mobile forming unit 21.

The width of the mobile forming unit 21 is substantially equal to the length of each flexible shaped portion 105 (fig. 4) to be made on the tubular element 100, measured parallel to the longitudinal axis Z of the latter.

In the example shown, the mobile forming unit 21 comprises a plurality of forming members 30 mounted on a conveyor belt 31, or conveyor chain, so that each of them is mobile along a closed loop path.

The conveyor belt 31 is closed in a loop on at least one pair of pulleys 33 (fig. 1). The conveyor belt 31 is driven in movement by a respective drive member, which can be of any known type which drives a driving pulley in rotation, comprised in the two pulleys 33.

A tension roller 42 can be provided, the position of which can possibly be adjusted in a known manner, to keep the conveyor belt 31 adequately taut.

Each forming member 30 comprises a work surface 32 shaped so as to have the plurality of corrugations 25, which comprise the ridges 25a and grooves 25b in succession. In fact, such work surfaces 32 are configured in such a way that, being located side by side and in succession, they contribute to forming, as a whole, the forming surface 23 of the mobile forming unit 21 (figs. 1 and 3) and the corresponding corrugations 25.

In greater detail, each forming member 30 is attached to the conveyor belt 31 by means of a support 34 on which a body 35 is mounted which in turn supports a forming element 36 on which the work surface 32 is created.

Each forming member 30 comprises two pins 37 located on two opposite sides of the body, aligned with each other and each rotatably supported by a respective bearing 38. Two guides 40 are provided to guide the sliding of the pins 37, disposed symmetrically with respect to each other along at least one segment of the closed loop path (fig. 5), more precisely, at least along the segment that coincides with the path of advance A, in order to ensure that all the forming members 30 follow exactly the same trajectory, thus forming a forming surface 23 without discontinuity along the path of advance A.

The forming element 36 can substantially have the shape of an inverted U, and defines a lower cavity 39 mating in shape with the flanks 41 of the body 35. For example, the cavity 39 and the flanks 41 are shaped in such a way as to create a same-shape coupling that allows to keep the forming element 36 firmly constrained to the body 35, even when the forming member 30 is traveling along the return branch of the closed loop path, on the opposite side to the path of advance A.

In some variants, not shown, each forming member 30 can comprise damping means, for example of the mechanical type, such as helical springs or similar elements, or of the hydraulic type, such as pistons or other suitable similar actuator members. The damping means are configured to ensure a desired elastic response of the forming members in response to the thrust stresses of the second forming unit 22. In some embodiments, adjustment elements are provided associated with the damping means to adjust the extent of the elastic response as above.

The forming surface 23 preferably has a convex shape and faces toward the second forming unit 22. The forming surface 23 has an angular extension of a defined angle [3 (fig. 1), for example comprised between about 45° and about 120°, the bisecting line of which preferably lies on a median axis Y, perpendicular to the longitudinal axis X and therefore, in the example provided, disposed in a vertical position.

The second forming unit 22, on the other hand, comprises a forming surface 24 of its own, shaped in such a way as to have a plurality of corrugations 26 (figs. 3, 4 and 4a) which comprise in succession ridges 26a and grooves 26b and which have the same linear pitch P (fig. 4a) of the ridges 25a and grooves 25b of the first forming unit 21, since they are exactly aligned with them. Therefore, in the example given here, the forming surface 24 (fig. 4) has ten ridges 24a and nine grooves 24b.

In the example given here, the second forming unit 22 is configured as a disc 50 located inside the rotating member 11. The disc 50 has a longitudinal axis XI of its own, or third longitudinal axis, which is parallel to the longitudinal axis X but distant therefrom by a certain value D (fig. 1), for example by a few millimeters, preferably between about 1 mm and about 5 mm, in the direction of the mobile forming unit 21.

Furthermore, the diameter of the disc 50 is such that the latter completely interferes with the tubular elements 100, which are made to rotate by the rotating member 11, when the same tubular elements 100 are at the lowest point of their rotation, that is, when they are located on the lower part of the median axis Y.

The width of the disc 50 (figs. 3 and 4) is substantially equal to the width of the forming surface 23 of the mobile forming unit 21, and, therefore, also substantially equal to the length of the flexible shaped portion 105 of the tubular elements 100, as explained above.

The circular peripheral surface of the disc 50 coincides with the forming surface 24 of the second forming unit 22.

Please note that the mobile forming unit 21 is positioned at a distance from the longitudinal axis X (fig. 1), and therefore from the rotating member 11, measured in the radial direction, along the median axis Y, such as to define, between the corrugations 26 of the disk 50 and the corrugations 25 of the mobile forming unit 21, a passage zone 60 (figs. 1 and 3), or hollow space, for the tubular elements 100, which has an amplitude, in the radial sense, that is not constant. In fact, the amplitude, in the radial sense, of this passage zone 60, which can be adjusted by an operator, ranges from a maximum value, in correspondence with the lateral ends of the mobile forming unit 21 (fig. 1), to a minimum value, in correspondence with the median axis Y, and it varies as a function of the distance D between the axes X and XI, which is also adjustable.

The passage zone 60 allows the tubular elements 100 being worked, which are made to rotate around the longitudinal axis X by the rotating member 11, to gradually engage with the external forming means 20, that is, with the corrugations 26 of the disc 50 and the corrugations 25 of the mobile forming unit 21, in a manner that is increasing and continuous for the first half of the angular amplitude 0, in order to then be freed in a decreasing and continuous manner in the second half of the angular amplitude 0. Furthermore, this engagement with the external forming means 20 occurs while the internal forming means 15, or the forming pins 13, if present, are inserted in the same tubular elements 100.

Please note that, in correspondence with the passage zone 60, the forming surface 23 of the mobile forming unit 21 and the forming surface 24 of the second forming unit 22 delimit, at the lower part and upper part respectively, the passage zone 60 in the which the flexible shaped portion 105 is created.

In accordance with some variants, not shown here but which a person of skill in the art will easily understand and in any case are comprised within the scope of the present invention, it is evident that the external forming members 20 can comprise only the mobile forming unit 21, or only the disk 50.

In the example provided here, the disc 50 is stationary and acts as a fixed element in contrast to the mobile forming unit 21.

In accordance with another variant, not shown, the disc 50 is mobile in rotation around its longitudinal axis X 1 , but at a rotation speed lower than the speed with which the forming surface 23 of the mobile forming unit 21 moves. Providing that both forming units 21, 22 are mobile allows to choose the number of rotations that the tubular elements 100 will be made to complete in the forming zone, as well as the extension of such forming zone. The rotation of the disc 50 can occur in the same sense of rotation S (fig. 1) as the rotating member, or in the opposite sense (clockwise), and it is commanded, for example, by a second electric motor, also of a known type which for simplicity is not shown in the drawings.

In accordance with one embodiment, shown in fig. 1, the apparatus 10 is configured to be associated, for example, with a device 70 for feeding tubular elements 100, which can be of any known type whatsoever. In the example given here, the feed device 70 is positioned, with respect to the apparatus 10, in such a way that each tubular element 100 is picked up by a respective gripping member when this is in an initial radial position Al, which is also the position in which there begins the angle of engagement a of the rotating member 11, rotating in the sense of rotation S, with each tubular element 100.

It is also provided that, for example, with the apparatus 10 there is associated a device 71 for picking up the tubular elements 100 already worked, which can be of any known type whatsoever and which is configured to pick up each tubular element 100 from the gripping members, after its shaping has been completed, that is, when each tubular element 100 is in a final radial position A4, for example after a rotation of about 280° from the initial angular position of supply, which corresponds to the amplitude of the angle of engagement a of each tubular element 100 with the rotating member 11 rotating in the sense of rotation S.

With reference to the embodiment of fig. 6, the external forming means 20 of the apparatus 10 can comprise a mobile forming unit 21, configured as a conveyor belt, and a plurality of second forming units 22, for example six, located parallel to each other and along the mobile forming unit 21.

The tubular elements 100 follow a substantially linear path of advance A which follows the upper segment of the closed loop path of the conveyor belt. The latter is shown schematically with the belt directly in contact with the tubular elements 100, which suggests that the forming surface 23 can be created directly on the belt. Alternatively, and preferably, the conveyor belt is of the type previously described and shown in figs. 1, 3 and 5.

Advantageously, each second forming unit 22 is included in a respective rotating member 11 (not shown for simplicity) which is provided with a plurality of forming pins 13 rotatable around a respective central axis of rotation, if such forming pins 13 are present. In fig. 6, the second forming units 22 are indicated as rotating, and preferably they all rotate at the same rotation speed. Alternatively, they can also be fixed and act as contrast members for the first forming unit 21.

With reference to the embodiment of fig. 7, the external forming means 20 of the apparatus 10 can provide that both the mobile forming unit 21 and also the second forming unit 22 are configured as conveyor belts. Also for this drawing, the schematic representation suggests that the forming surfaces 23, 24 are created directly on the belts; however, it is preferable to provide that the conveyor belts 21, 22 are of the type provided with a plurality of forming members 30, as described previously with reference to the embodiment shown in figs. 1 and 3-5.

We will now describe the operation of the apparatus 10 described heretofore, which corresponds to the method for shaping tubular products, that is, tubular elements 100, preferably made of paper, from which straws 101 are preferably obtained, in accordance with the present invention.

The apparatus 10 (fig. 1) is started by commanding the electric motors which make rotate both the rotating member 11 , around its own axis of rotation consisting of the longitudinal axis X, and also the mobile forming unit 21, the forming members 30 of which are moved along the closed loop path by the conveyor belt 31.

If the rotation of the disk 50 is also provided, the corresponding electric motor will be commanded accordingly.

The apparatus 10 then begins to receive the tubular elements 100 in correspondence with the initial radial position Al, in which the feed device 70 supplies the tubular elements 100, one at a time, to the gripping members, which are rotating together with the rotating member 11 in the sense of rotation S (fig. 1). In this initial radial position Al, if the forming pins 13 are provided, these are in their first operating position, that is, completely retracted with respect to the tubular element 100.

Continuing the rotation of the rotating member 11, the gripping members, each of which carries a respective tubular element 100, arrive in an angular position of start of deformation A2 (fig. 1), in correspondence with which the tubular elements 100 enter the passage zone 60. In this angular position of start of deformation A2, the corresponding forming pins 13 (fig. 1), if provided, have moved into their second operating position and have therefore entered inside the respective tubular elements 100, since they are coaxial to them.

Subsequently, the gripping members continue their movement until they reach, after an additional rotation corresponding to the angle [3 (fig. 1), an angular position of end of deformation A3, in correspondence with which the tubular elements 100 exit from the passage zone 60. While they pass through the passage zone 60, the tubular elements 100 are made to roll around their longitudinal axis Z, in a sense of rotation R, which corresponds to the sense of rotation S of the rotating member 11 , thanks to the movement of the forming surface 23 of the mobile forming unit 21.

This rolling of the tubular elements 100 is determined, in particular, both by the interaction of the disc 50 with the mobile forming unit 21, as well as by the misaligned disposition of the former with respect to the rotating member 11 , which allows the corrugations 26 of the disc 50 to arrive in proximity of the corrugations 25 of the mobile forming unit 21.

As they pass through the passage zone 60, the tubular elements 100 interact both with the corrugations 25 that the mobile forming unit 21 is provided with, and also with the corrugations 26 that the disk 50 is provided with, as can be better observed in figs. 4 and 4a. The ridges 25a and 26a, and the grooves 25b and 26b of the corrugations 25 and 26 therefore interact with the ridges 14a and the grooves 14b of the corrugated portion 14 of the forming pin 13, if present, in order to form the ridges 105a and the grooves 105b of the flexible shaped portion 105.

Please note that the rolling of each tubular element 100 around its longitudinal axis Z allows to accentuate the deformation action that the internal and external forming members exert on the same tubular elements 100.

When the gripping members reach the angular position of end of deformation A3 (fig. 1), the flexible shaped portion 105 of the tubular elements 100 has been created (fig. 2). From this angular position of end of deformation A3, the forming pins 13 gradually begin to retract in order to return from their second operating position to their first operating position, in the embodiment in which such forming pins 13 are provided.

Subsequently, continuing the rotation of the rotating member 11 (fig. 1), the gripping members reach the radial position of delivery A4, in which they move into their open position and allow the delivery of the tubular elements 100, one after the other, to the pick-up device 71.

Still continuing the rotation of the rotating member 11, the gripping members again reach the initial radial position Al, in which they receive another tubular element 100 and are ready to repeat the working cycle previously described.

It is evident that at the end of the working cycle, due to the deformation impressed on the tubular elements 100, which made it possible to create the flexible shaped portion 105, each of the tubular elements 100 has a length L shorter than its initial length. Similarly, this deformation can cause a localized increase in the nominal external diameter of the straws, in particular in correspondence with the flexible shaped portion 105, the ridges 105a of which can have a maximum extension, in the radial direction, corresponding to a diameter larger than the nominal diameter mentioned above.

It is clear that modifications and/or additions of parts or steps may be made to the apparatus and to the method as described heretofore, without departing from the field and scope of the present invention, as defined by the claims. In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.

Claims

22

1. Apparatus (10) for forming flexible shaped portions (105) on tubular elements (100), preferably made of paper, wherein said flexible shaped portions (105) are defined by a succession of annular ridges (105a) and grooves (105b) substantially coaxial to a first longitudinal axis (Z) of each of said tubular elements (100), wherein said apparatus (10) comprises a conveying unit (11) of said tubular elements (100), configured to convey said tubular elements (100) along a path of advance (A), external forming means (20) configured to locally shape each of said tubular elements (100) by acting on an external surface (103) thereof, wherein said external forming means (20) comprise a first forming unit (21) that has a plurality of forming members (30) configured to act on said tubular elements (100) so as to form said flexible shaped portions (105), characterized in that said forming members (30) are disposed side by side and are configured to be moved along a closed loop path.

2. Apparatus (10) as in claim 1 , characterized in that said external forming means (20) also comprise a second forming unit (22), configured to act on the tubular elements (100) in cooperation with said first forming unit (21).

3. Apparatus (10) as in claim 2, characterized in that said second forming unit (22) is disposed so as to be completely inscribed within the overall size of said conveying unit (11) and is conformed as a cylindrical surface (50) that has an axis of rotation (XI) which is parallel to an axis of rotation (X) of said conveying unit (11) and distant by a determinate value (D) comprised between one and fifteen millimeters.

4. Apparatus (10) as in claim 2 or 3, characterized in that said first and second forming units (21, 22) comprise a respective plurality of corrugations (25, 26) which define a respective succession of ridges (25a, 26a) and grooves (25b, 26b), said first and second forming units (21, 22) being opposite each other with a passage zone (60) in the middle to selectively receive said tubular elements (100) in contact with the respective plurality of corrugations (25, 26).

5. Apparatus (10) as in any one of the previous claims from 2 to 4, characterized in that said second forming unit (22) is fixed or mobile in the same sense of movement as the first forming unit (21), and it is configured to move at a slower speed than the speed of the first forming unit (21).

6. Apparatus (10) as in any claim hereinbefore, characterized in that said forming members (30) are mounted on a common conveyor (31).

7. Apparatus (10) as in claim 6, characterized in that each forming member (30) comprises a support (34) connected to said conveyor (31), a body (35) attached to said support (34), and a forming element (36) mounted on said body (35) and on which there is created a work surface (32) that acts on said tubular elements (100).

8. Apparatus (10) as in any claim hereinbefore, characterized in that it also comprises internal forming means (15) configured to act from the inside of said tubular elements (100) and disposed so as to cooperate with the external forming means (20) in creating said flexible shaped portions (105).

9. Apparatus (10) as in claim 8, characterized in that said internal forming means (15) comprise a corrugated portion (14) having a profile formed by a succession of internal annular ridges (14a) and grooves (14b).

10. Apparatus (10) as in any claim hereinbefore, characterized in that each forming member (30) of said plurality of forming members (30) is driven to move autonomously from the remaining others.

11. Method to make flexible shaped portions (105) on tubular elements (100), preferably made of paper, wherein said flexible shaped portions (105) are defined by a succession of annular ridges (105a) and grooves (105b) substantially coaxial to a first longitudinal axis (Z) of each of said tubular elements (100), wherein said method provides a step of conveying said tubular elements (100) along a path of advance (A) by means of a conveying unit (11), and a forming step, during which external forming means (20) comprising a plurality of forming members (30) act on an external surface (103) of said tubular elements (100) while they advance along said path of advance (A), so as to form said flexible shaped portions (105), characterized in that during said forming step it is provided to move, along a closed loop path which develops for a segment of said path of advance (A), said plurality of forming members (30) of a first forming unit (21).

12. Method as in claim 11, characterized in that during said forming step it is provided to act on the tubular elements (100) also by means of a second forming unit (22), comprised in said external forming means (20), cooperating with said first forming unit (21).

13. Method as in claim 12, characterized in that it provides to keep said second forming unit (22) fixed or to move the latter in a sense that is concordant with said first forming unit (21), but at a slower speed than the speed of said first forming unit (21).

14. Method as in any claim 11 - 13, characterized in that it also provides to drive a conveyor (31) in movement, on which said plurality of forming members

(30) is mounted, so as to move the latter along said closed loop path.

15. Method as in any claim 11 - 14, characterized in that it is provided to selectively insert, inside said tubular elements (100), internal forming means (15) which are configured to locally shape each of said tubular elements (100) in order to make said flexible shaped portion (105), by acting on an internal surface (102) thereof, in association with said external forming means (20).