Patent Description:
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.

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 <NUM>-<NUM>, 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 <CIT>, <CIT> and <CIT>.

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 <CIT> 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 <CIT> and <CIT> as above, forming mandrels are provided, configured to be inserted inside the straws to be deformed.

In the solution described in document <CIT>, 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 <NUM>°, 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.

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.

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

By way of a non-limiting example, the machine for the automated production of straws can be configured as that described in <CIT>or <CIT> 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 <NUM>, disposed in succession along a path of advance A of the tubular elements <NUM>, a portion of which is shown with a dashed line in <FIG>.

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

To better understand the inventive concept of the present invention, before describing the apparatus <NUM> 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 <NUM> by using the apparatus <NUM>, 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>, the tubular element <NUM> can be configured as a single hollow tubular body with an oblong shape and a longitudinal axis Z, from which a straw <NUM> is preferably obtained.

Each tubular element <NUM> comprises an internal surface <NUM> and an external surface <NUM>, which define a cylindrical wall having a certain thickness, for example comprised between about <NUM> and about <NUM>. Purely as an indication, the tubular element <NUM> can have an external diameter comprised between about <NUM> and about <NUM>, preferably between about <NUM> and about <NUM>.

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

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

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

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

The rotating member <NUM> 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 <NUM> rotating coaxially with respect to the longitudinal axis X. For example, the rotating member <NUM> is made to rotate in a certain sense of rotation S (<FIG>), which is counterclockwise if viewed from the front of the apparatus <NUM>.

The apparatus <NUM> 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 <NUM>°.

Each gripping member is configured to selectively grip or release a tubular element <NUM> 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 <NUM>, for example for a defined angle of engagement α (<FIG>) corresponding to an analogous angle of rotation of the rotating member <NUM>.

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 <NUM>.

In the example provided here, the apparatus <NUM> comprises a plurality of forming pins <NUM> (<FIG>) suitably shaped and configured to be selectively and temporarily inserted inside the tubular elements <NUM>, 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 <NUM> can be without the forming pins <NUM>.

All the forming pins <NUM> 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 <NUM> is angularly coordinated with the disposition of the gripping members, so that each tubular element <NUM> is temporarily and selectively held from the outside by a respective gripping member, and a corresponding forming pin <NUM> is selectively and temporarily inserted inside it.

With particular reference to <FIG>, we will describe in greater detail the structure of each forming pin <NUM>, 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 <NUM>.

On the cylindrical stem 13a there is a corrugated portion <NUM>, 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>) 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 <NUM> is inserted inside a respective tubular element <NUM>, coincides with the axis of the forming pin <NUM>, since the latter is coaxial to the tubular element.

In one embodiment, given here by way of example, the corrugated portion <NUM> 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 <NUM>, together with their corrugated portions <NUM>, define internal forming means <NUM> of the tubular elements <NUM> which are configured to interact with the internal surface <NUM> of the latter during the method for making the flexible shaped portion <NUM> on such elements.

The forming pins <NUM> 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 <NUM>, and a second operating position, in which they are inside the tubular elements <NUM>, and vice versa, with a complete cycle for each <NUM>° rotation of the rotating member <NUM>.

The apparatus <NUM> also comprises external forming means <NUM> (<FIG> and <FIG>), configured to cooperate with the internal forming means <NUM> in order to create the flexible shaped portions <NUM> (<FIG>) on the tubular element <NUM>, as will be described in detail below.

The external forming means <NUM> substantially comprise a mobile forming unit <NUM>, also called the first forming unit, and a second forming unit <NUM> disposed coplanar with the first mobile unit <NUM>, and configured to cooperate with the latter and possibly with the forming pins <NUM>, if present, in order to create the flexible shaped portions <NUM> (<FIG>) on the tubular elements <NUM>, as will be described in detail below.

Please note that in other embodiments of the present invention, in which the apparatus <NUM> is without the forming pins <NUM>, the flexible shaped portions <NUM> are created only by means of the external forming means <NUM>, thanks to the cooperation of the first and second forming units <NUM>, <NUM>.

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

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

Please note that when each forming pin <NUM> is in its second operating position, that is, inside one of the tubular elements <NUM> (<FIG>), its ridges 14a and grooves 14b are offset by half of the linear pitch P (<FIG>), that is, by P/<NUM>, with respect to the ridges 25a and grooves 25b of the mobile forming unit <NUM>.

The width of the mobile forming unit <NUM> is substantially equal to the length of each flexible shaped portion <NUM> (<FIG>) to be made on the tubular element <NUM>, measured parallel to the longitudinal axis Z of the latter.

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

The conveyor belt <NUM> is closed in a loop on at least one pair of pulleys <NUM> (<FIG>). The conveyor belt <NUM> 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 <NUM>.

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

Each forming member <NUM> comprises a work surface <NUM> shaped so as to have the plurality of corrugations <NUM>, which comprise the ridges 25a and grooves 25b in succession.

In fact, such work surfaces <NUM> 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 <NUM> of the mobile forming unit <NUM> (<FIG> and <FIG>) and the corresponding corrugations <NUM>.

In greater detail, each forming member <NUM> is attached to the conveyor belt <NUM> by means of a support <NUM> on which a body <NUM> is mounted which in turn supports a forming element <NUM> on which the work surface <NUM> is created.

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

The forming element <NUM> can substantially have the shape of an inverted U, and defines a lower cavity <NUM> mating in shape with the flanks <NUM> of the body <NUM>. For example, the cavity <NUM> and the flanks <NUM> are shaped in such a way as to create a same-shape coupling that allows to keep the forming element <NUM> firmly constrained to the body <NUM>, even when the forming member <NUM> 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 <NUM> 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 <NUM>. 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 <NUM> preferably has a convex shape and faces toward the second forming unit <NUM>. The forming surface <NUM> has an angular extension of a defined angle β (<FIG>), for example comprised between about <NUM>° and about <NUM>°, 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 <NUM>, on the other hand, comprises a forming surface <NUM> of its own, shaped in such a way as to have a plurality of corrugations <NUM> (<FIG>) which comprise in succession ridges 26a and grooves 26b and which have the same linear pitch P (<FIG>) of the ridges 25a and grooves 25b of the first forming unit <NUM>, since they are exactly aligned with them. Therefore, in the example given here, the forming surface <NUM> (<FIG>) has ten ridges 24a and nine grooves 24b.

In the example given here, the second forming unit <NUM> is configured as a disc <NUM> located inside the rotating member <NUM>. The disc <NUM> has a longitudinal axis X1 of its own, or third longitudinal axis, which is parallel to the longitudinal axis X but distant therefrom by a certain value D (<FIG>), for example by a few millimeters, preferably between about <NUM> and about <NUM>, in the direction of the mobile forming unit <NUM>.

Furthermore, the diameter of the disc <NUM> is such that the latter completely interferes with the tubular elements <NUM>, which are made to rotate by the rotating member <NUM>, when the same tubular elements <NUM> 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 <NUM> (<FIG>) is substantially equal to the width of the forming surface <NUM> of the mobile forming unit <NUM>, and, therefore, also substantially equal to the length of the flexible shaped portion <NUM> of the tubular elements <NUM>, as explained above.

The circular peripheral surface of the disc <NUM> coincides with the forming surface <NUM> of the second forming unit <NUM>.

Please note that the mobile forming unit <NUM> is positioned at a distance from the longitudinal axis X (<FIG>), and therefore from the rotating member <NUM>, measured in the radial direction, along the median axis Y, such as to define, between the corrugations <NUM> of the disk <NUM> and the corrugations <NUM> of the mobile forming unit <NUM>, a passage zone <NUM> (<FIG> and <FIG>), or hollow space, for the tubular elements <NUM>, which has an amplitude, in the radial sense, that is not constant. In fact, the amplitude, in the radial sense, of this passage zone <NUM>, which can be adjusted by an operator, ranges from a maximum value, in correspondence with the lateral ends of the mobile forming unit <NUM> (<FIG>), 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 X1, which is also adjustable.

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

Please note that, in correspondence with the passage zone <NUM>, the forming surface <NUM> of the mobile forming unit <NUM> and the forming surface <NUM> of the second forming unit <NUM> delimit, at the lower part and upper part respectively, the passage zone <NUM> in the which the flexible shaped portion <NUM> 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 <NUM> can comprise only the mobile forming unit <NUM>, or only the disk <NUM>.

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

In accordance with another variant, not shown, the disc <NUM> is mobile in rotation around its longitudinal axis X1, but at a rotation speed lower than the speed with which the forming surface <NUM> of the mobile forming unit <NUM> moves. Providing that both forming units <NUM>, <NUM> are mobile allows to choose the number of rotations that the tubular elements <NUM> will be made to complete in the forming zone, as well as the extension of such forming zone. The rotation of the disc <NUM> can occur in the same sense of rotation S (<FIG>) 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>, the apparatus <NUM> is configured to be associated, for example, with a device <NUM> for feeding tubular elements <NUM>, which can be of any known type whatsoever.

In the example given here, the feed device <NUM> is positioned, with respect to the apparatus <NUM>, in such a way that each tubular element <NUM> is picked up by a respective gripping member when this is in an initial radial position A1, which is also the position in which there begins the angle of engagement α of the rotating member <NUM>, rotating in the sense of rotation S, with each tubular element <NUM>.

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

With reference to the embodiment of <FIG>, the external forming means <NUM> of the apparatus <NUM> can comprise a mobile forming unit <NUM>, configured as a conveyor belt, and a plurality of second forming units <NUM>, for example six, located parallel to each other and along the mobile forming unit <NUM>.

The tubular elements <NUM> 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 <NUM>, which suggests that the forming surface <NUM> can be created directly on the belt. Alternatively, and preferably, the conveyor belt is of the type previously described and shown in <FIG>, <FIG> and <FIG>.

Advantageously, each second forming unit <NUM> is included in a respective rotating member <NUM> (not shown for simplicity) which is provided with a plurality of forming pins <NUM> rotatable around a respective central axis of rotation, if such forming pins <NUM> are present. In <FIG>, the second forming units <NUM> 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 <NUM>.

With reference to the embodiment of <FIG>, the external forming means <NUM> of the apparatus <NUM> can provide that both the mobile forming unit <NUM> and also the second forming unit <NUM> are configured as conveyor belts. Also for this drawing, the schematic representation suggests that the forming surfaces <NUM>, <NUM> are created directly on the belts; however, it is preferable to provide that the conveyor belts <NUM>, <NUM> are of the type provided with a plurality of forming members <NUM>, as described previously with reference to the embodiment shown in <FIG> and <FIG>.

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

The apparatus <NUM> (<FIG>) is started by commanding the electric motors which make rotate both the rotating member <NUM>, around its own axis of rotation consisting of the longitudinal axis X, and also the mobile forming unit <NUM>, the forming members <NUM> of which are moved along the closed loop path by the conveyor belt <NUM>.

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

The apparatus <NUM> then begins to receive the tubular elements <NUM> in correspondence with the initial radial position A1, in which the feed device <NUM> supplies the tubular elements <NUM>, one at a time, to the gripping members, which are rotating together with the rotating member <NUM> in the sense of rotation S (<FIG>). In this initial radial position A1, if the forming pins <NUM> are provided, these are in their first operating position, that is, completely retracted with respect to the tubular element <NUM>.

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

Subsequently, the gripping members continue their movement until they reach, after an additional rotation corresponding to the angle β (<FIG>), an angular position of end of deformation A3, in correspondence with which the tubular elements <NUM> exit from the passage zone <NUM>. While they pass through the passage zone <NUM>, the tubular elements <NUM> 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 <NUM>, thanks to the movement of the forming surface <NUM> of the mobile forming unit <NUM>.

This rolling of the tubular elements <NUM> is determined, in particular, both by the interaction of the disc <NUM> with the mobile forming unit <NUM>, as well as by the misaligned disposition of the former with respect to the rotating member <NUM>, which allows the corrugations <NUM> of the disc <NUM> to arrive in proximity of the corrugations <NUM> of the mobile forming unit <NUM>.

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

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

When the gripping members reach the angular position of end of deformation A3 (<FIG>), the flexible shaped portion <NUM> of the tubular elements <NUM> has been created (<FIG>). From this angular position of end of deformation A3, the forming pins <NUM> 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 <NUM> are provided.

Subsequently, continuing the rotation of the rotating member <NUM> (<FIG>), 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 <NUM>, one after the other, to the pick-up device <NUM>.

Still continuing the rotation of the rotating member <NUM>, the gripping members again reach the initial radial position A1, in which they receive another tubular element <NUM> 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 <NUM>, which made it possible to create the flexible shaped portion <NUM>, each of the tubular elements <NUM> 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 <NUM>, 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.

Claim 1:
Apparatus (<NUM>) for forming flexible shaped portions (<NUM>) on tubular elements (<NUM>), preferably made of paper, wherein said flexible shaped portions (<NUM>) 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 (<NUM>), wherein said apparatus (<NUM>) comprises a conveying unit (<NUM>) of said tubular elements (<NUM>), configured to convey said tubular elements (<NUM>) along a path of advance (A), external forming means (<NUM>) configured to locally shape each of said tubular elements (<NUM>) by acting on an external surface (<NUM>) thereof, wherein said external forming means (<NUM>) comprise a first forming unit (<NUM>) that has a plurality of forming members (<NUM>) configured to act on said tubular elements (<NUM>) so as to form said flexible shaped portions (<NUM>), characterized in that said forming members (<NUM>) are disposed side by side and are configured to be moved along a closed loop path.