Patent Description:
The present invention relates to a method and to a unit to bend a straw.

Straws are known which provide a corrugated intermediate portion in order to allow the bending of the straw so as to assume the most suitable shape in use to satisfy the user.

For some applications, a straw is packaged individually (namely, it is inserted singly into its own wrap) after being bent in a "U"-shape (namely, by <NUM>°) at the corrugated intermediate portion (the purpose of bending in a "U"-shape is to reduce the overall dimensions of the straw); typically, it is required to individually package the "U"-bent straws when the straws have to be fixed (glued) to the back wall of a beverage container.

The Patent application <CIT> represents the closest prior art and describes a high-speed straw bending machine.

The object of the present invention is to provide a method and a unit to bend a straw that allow operating at a high processing speed (measured by the number of pieces produced per unit of time) while, at the same time, maintaining a high production quality (namely, without damaging the straw during bending).

According to the present invention, a method and a unit to bend a straw are provided, according to what is established in the attached claims.

The present invention will now be described with reference to the attached drawings, which illustrate a non-limiting embodiment thereof, wherein:.

In <FIG>, number <NUM> denotes as a whole a straw (made of paper or plastic) which is applied to the back of a beverage package. The straw <NUM> has a flat end <NUM> (which is grasped by the user's lips) and a pointed end <NUM> (to more effectively break through the cap that seals a dispensing opening of the package).

In addition, the straw <NUM> has a corrugated intermediate portion <NUM> at which the straw <NUM> can be easily bent and without breaking (namely, in an elastic manner) so as to assume in use the most suitable shape to satisfy the user.

The straw <NUM> is packaged individually (namely, it has been inserted singly in its own wrap <NUM> not illustrated in <FIG> and illustrated in <FIG>) after being bent in a "U"-shape (namely, by <NUM>°) at the corrugated intermediate portion <NUM> (the purpose of the "U"-bending is to reduce the overall dimensions of the straw <NUM> in order to remain within the overall dimensions of the back wall of the package to which the straw <NUM> is applied).

In <FIG>, number <NUM> denotes as a whole a packing machine which receives the straws <NUM> from a manufacturing machine (not illustrated), corrugates the straws <NUM>, bends the straws <NUM> in a "U"-shape, and inserts the straws <NUM> in corresponding wraps <NUM>.

The packing machine <NUM> comprises a hopper <NUM> which is designed to contain a mass of straws <NUM> coming from the manufacturing machine and which move progressively downwards by gravity, namely, towards the bottom of the hopper <NUM>. As an alternative to the hopper <NUM>, the packing machine <NUM> could provide any type of buffer or collector for a mass of straws. As a further alternative, the packing machine <NUM> could receive the straws in an orderly manner (namely, not collected in a mass), for example directly from the manufacturing machine.

A pick-up conveyor <NUM> is arranged on the bottom of the hopper <NUM>, the conveyor picks up a succession of straws <NUM> by feeding the latter crosswise (namely, perpendicularly to a longitudinal axis of the straws <NUM>); according to a preferred embodiment, the pick-up conveyor <NUM> is a conveyor belt, namely, it comprises a flexible belt which is closed in a loop around two end pulleys and supports a plurality of suction seats, each designed to house a corresponding straw <NUM>. According to embodiments not illustrated, the pick-up conveyor <NUM> could comprise one or more conveying drums; at least one of these conveying drums could be a conical drum.

The packing machine <NUM> comprises a corrugator drum <NUM> which is mounted so as to rotate around a rotation axis <NUM>, has a plurality of suction seats each designed to house a corresponding straw <NUM>, and receives the straws <NUM> directly from the pick-up conveyor <NUM>. A corrugator device <NUM> is arranged along the periphery of the corrugator drum <NUM>, which corrugates the straws <NUM>, namely, creates the corrugated intermediate portion <NUM> of each straw <NUM>.

According to an embodiment not illustrated, the packing machine <NUM> could receive already corrugated straws <NUM>; in this case, the packing machine <NUM> does not comprise any corrugator drum <NUM>.

The packing machine <NUM> comprises a bending drum <NUM> which is mounted so as to rotate around a rotation axis <NUM> (parallel to the rotation axis <NUM>), has a plurality of suction seats <NUM> (illustrated in <FIG>) each designed to house a corresponding straw <NUM>, and receives the straws <NUM> directly from the corrugator drum <NUM>. Two bending elements <NUM> and <NUM> and an accompanying element <NUM> (better illustrated in <FIG>, <FIG> and <FIG>) are arranged around the rotation axis <NUM> in a fixed position (namely, integral with a frame of the packing machine <NUM> and, therefore, motionless), which are coupled to the bending drum <NUM> and interact with the straws <NUM> carried by the suction seats <NUM> for bending the straws <NUM> in a "U"-shape.

The packing machine <NUM> comprises a wrapping drum <NUM> which is mounted so as to rotate around a rotation axis <NUM> (parallel to the rotation axis <NUM>), has a plurality of suction seats <NUM> each designed to house a wrapping sheet and a straw <NUM> bent in a "U"-shape. Each suction seat <NUM> of the wrapping drum <NUM> receives a strip <NUM> of wrapping material which is bent in a "U"-shape inside the suction seat <NUM> (where it is held by suction) and then receives a straw <NUM> bent in a "U"-shape (which is arranged inside the strip <NUM> of wrapping material bent in a "U"-shape) subsequently and directly from the bending drum <NUM>. In particular, an inserter drum <NUM> is provided which inserts, in each suction seat <NUM> of the wrapping drum <NUM>, a portion of the strip <NUM> of wrapping material that is bent in a "U"-shape inside the suction seat <NUM>. An applicator drum <NUM> is coupled to the wrapping drum <NUM>, which applies, to each wrapping sheet bent in a "U"-shape and containing a straw <NUM> bent in a "U"-shape, a corresponding lid (defined by a further strip of wrapping material, thus completing the formation of a wrap <NUM>) which is fixed by heat sealing or by gluing (thanks to the presence of glue which is previously applied to the strip <NUM> of wrapping material or to the lid).

The packing machine <NUM> comprises an outlet conveyor <NUM> which receives a continuous strip of wraps <NUM> containing respective straws <NUM> from the wrapping drum <NUM> and feeds the wraps <NUM> towards an outlet of the packing machine <NUM>.

According to a particular embodiment, the outlet conveyor <NUM> is a conveyor belt, namely, it comprises a flexible belt which is closed in a loop around two end pulleys and supports a plurality of suction seats each designed to house a corresponding wrap <NUM>. According to a preferred embodiment, the applicator drum <NUM> is arranged at the exchange station between the wrapping drum <NUM> and the outlet conveyor <NUM>.

As illustrated in <FIG>, the bending element <NUM> is shaped like an arc of a circle, is arranged in a fixed position around the rotation axis <NUM> and has a radial position which is variable so that the rotation of the bending drum <NUM> causes a progressive relative radial movement between the bending element <NUM> and the seats <NUM>; namely, each seat <NUM> rotating around the rotation axis <NUM> together with the rest of the bending drum <NUM>, "perceives" a radial movement of the bending element <NUM> due to the variation of the radial position of the bending element <NUM> along its circumferential extension. It is important to note that the variable radial position of the bending element <NUM> refers to the active side of the bending element <NUM>, namely, the side of the bending element <NUM> that comes into contact with the straws <NUM> carried by the seats <NUM>.

According to what is illustrated in <FIG>, the bending element <NUM> is shaped like an arc of a circle, is arranged in a fixed position around the rotation axis <NUM> and has an axial position which is variable so that the rotation of the bending drum <NUM> causes a relative progressive axial movement between the bending element <NUM> and the seats <NUM>; namely, each seat <NUM> rotating around the rotation axis <NUM> together with the rest of the bending drum <NUM>, "perceives" an axial movement of the bending element <NUM> due to the variation of the axial position of the bending element <NUM> along its circumferential extension. It is important to note that the variable axial position of the bending element <NUM> refers to the active side of the bending element <NUM>, namely, the side of the bending element <NUM> that comes into contact with the straws <NUM> carried by the seats <NUM>.

According to what is illustrated in <FIG>, the accompanying element <NUM> is ring-shaped (but alternatively it could be shaped only like an arc of a circle since a part of the accompanying element <NUM> has no active function, that is, it never makes contact with the straws <NUM> carried by the seats <NUM>), is arranged in a fixed position around the rotation axis <NUM> and has a radial position which is variable so that the rotation of the bending drum <NUM> causes a relative progressive radial movement between the accompanying element <NUM> and the seats <NUM>; namely, each seat <NUM> rotating around the rotation axis <NUM> together with the rest of the bending drum <NUM>, "perceives" a radial movement of the accompanying element <NUM> due to the variation of the radial position of the accompanying element <NUM> along its circumferential extension. It is important to note that the variable radial position of the accompanying element <NUM> refers to the active side of the accompanying element <NUM>, namely, the side of the accompanying element <NUM> that comes into contact with the straws <NUM> carried by the seats <NUM>.

According to what is illustrated in <FIG> and <FIG>, the bending drum <NUM> has a central circumferential slit <NUM> (i.e., which develops for <NUM>° around the rotation axis <NUM>), which is oriented radially and is configured to contain the accompanying element <NUM>; namely, the accompanying element <NUM> is arranged inside the circumferential slit <NUM> of the bending drum <NUM>.

According to what is illustrated in <FIG> and <FIG>, each seat <NUM> comprises two suction walls <NUM> (namely, provided with small holes that can be connected when necessary to a suction source) which are axially oriented, are arranged at a certain distance from one another, and are designed to receive and hold two opposite ends of a straight straw <NUM> (namely, without bends and, therefore, still having a completely rectilinear shape). According to what is illustrated in <FIG>, the two suction walls <NUM> have a semi-circle shape to reproduce in negative the shape of a straw <NUM> and, therefore, also to laterally contain a straw <NUM>.

According to what is illustrated in <FIG> and <FIG>, at each seat <NUM> the bending drum <NUM> is provided with a cavity <NUM> (namely, a hole) which is radially arranged further inwards than the seat <NUM>, namely, it extends starting from the seat <NUM> towards the centre (namely, the rotation axis <NUM>). In particular, the circumferential slit <NUM>, which contains the accompanying element <NUM>, opens into the cavity <NUM>, namely the circumferential slit <NUM> originates from a bottom of each cavity <NUM>. Each cavity <NUM> has an outer portion <NUM> delimited on one side by a wall <NUM> radially arranged and, on the opposite side, by a wall <NUM> that forms an acute angle (of the order of about <NUM>°) with the wall <NUM> (and remains at a certain distance from the wall <NUM>); furthermore, each cavity <NUM> has an inner portion <NUM> which is radially arranged further inwards than the outer portion <NUM> and is delimited on one side by the wall <NUM> (namely, by the same radially arranged wall <NUM>, which also delimits the outer portion <NUM>) and on the opposite side by a wall <NUM> that is connected to the wall <NUM> (namely, it forms a joining corner with the wall <NUM>) and is arranged radially and, therefore, parallel to the wall <NUM>.

The methods for bending a straw <NUM> in a "U"-shape in the bending drum <NUM> are described in the following and with particular reference to what is illustrated in <FIG>.

Initially, and as illustrated in <FIG>, the straw <NUM> is fed straight to the seat <NUM> and then the two opposite ends of the straw <NUM> engage the two walls <NUM> of the seat <NUM> (which initially hold the straw <NUM> by suction).

Subsequently and as illustrated in <FIG>, the straw <NUM> is progressively pushed into the cavity <NUM> by means of the action of the bending element <NUM> which moves radially relative to the seat <NUM> for at least partially bending the straw <NUM> in a "U"-shape against (at least) the wall <NUM> of the cavity <NUM>; the introduction of the straw <NUM> into the cavity <NUM> is accompanied by means of the action of the accompanying element <NUM>, which is arranged on the opposite side of the straw <NUM> relative to the bending element <NUM> and moves radially relative to the seat <NUM> (namely, the bending element <NUM> and the accompanying element <NUM> "pinch" the straw <NUM> between one another to guide the radial movement of the straw <NUM> on both sides and, therefore, control the exact radial position of the straw <NUM> at all times).

According to a preferred embodiment illustrated in <FIG> (and also in <FIG> which reproduces <FIG> on an enlarged scale), the bending element <NUM> pushes the straw <NUM> inside the inner portion <NUM> of the cavity <NUM> until it reaches a bottom of the inner portion <NUM>, namely, until the straw <NUM> is in contact with the bottom of the inner portion <NUM>.

According to what is illustrated in <FIG>, once the straw <NUM> is at least partially bent in a "U"-shape inside the inner portion <NUM> of the cavity <NUM>, the at least partially "U"-bent straw <NUM> is subsequently extracted from the inner portion <NUM> of the cavity <NUM> by pushing the straw <NUM> radially outwards by means of the action of the accompanying element <NUM> (which is arranged on the opposite side of the straw <NUM> relative to the bending element <NUM> and moves radially relative to the seat <NUM>).

As illustrated in <FIG>, simultaneously with the radial thrust towards the outside of the straw <NUM> at least partially bent in a "U"-shape, operated by the accompanying element <NUM>, the bending element <NUM> also intervenes by starting to push the straw <NUM> at least partially bent in a "U"-shape and extracted from the inner portion <NUM>, against the wall <NUM> of the outer portion <NUM> of the cavity <NUM>. According to a preferred embodiment illustrated in <FIG>, the bending element <NUM> comprises a holding tooth <NUM> which engages the end <NUM> of the straw <NUM> so as to prevent the straw <NUM> from being (accidentally and obviously in a completely undesired manner) elasticity "shot" out of the cavity <NUM> while being bent against the wall <NUM> of the outer portion <NUM>. According to what is illustrated in <FIG>, by means of the action of the bending element <NUM> the bending of the straw <NUM> in a "U"-shape is completed by pushing the at least partially "U"-bent straw <NUM> against the wall <NUM> of the outer portion <NUM>.

Finally, and as illustrated in <FIG>, the straw <NUM> completely bent in a "U"-shape is rotated by <NUM>° by means of the action of the bending element <NUM> so as to be arranged "flat" (instead of "standing upright"), consequently coming out of the cavity <NUM> (as better illustrated in <FIG>, which reproduces <FIG> on an enlarged scale). Preferably, the accompanying element <NUM> pushes the straw <NUM> towards the bending element <NUM> until the rotation by <NUM>° of the completely "U"-bent straw <NUM>, keeping the straw <NUM> clamped between the accompanying element <NUM> and the bending element <NUM>.

Preferably, the cavity <NUM> has a circumferential width which is only slightly larger than the thickness of the straw <NUM> (as illustrated in <FIG>) so as to be able to contain the partially or completely "U"-bent straw <NUM> only when the partially or completely "U"-bent straw <NUM> is arranged "standing upright" (namely, it is radially oriented). Beside the cavity <NUM> a housing <NUM> is obtained, (illustrated in <FIG>), which is shaped so as to contain the completely "U"-bent straw <NUM> after its rotation by <NUM>° and, therefore, after its extraction from the cavity <NUM>; namely, the rotation by <NUM>° causes the extraction of the completely "U"-bent straw <NUM> from the cavity <NUM> and the subsequent insertion of the completely "U"-bent straw <NUM> into the housing <NUM>.

According to a possible embodiment illustrated in <FIG>, the wall <NUM> of each cavity <NUM> is provided with a pneumatic device <NUM> which can be operated to generate a blast of compressed air which pushes the straw <NUM> towards the wall <NUM> of the outer portion <NUM>; the function of the pneumatic device <NUM> (which is activated only when the at least partially "U"-bent straw is extracted from the inner portion <NUM> of the cavity <NUM>) is to prevent a straw <NUM> from remaining too close to the wall <NUM> and, therefore, not being able to be rotated correctly by <NUM>° in order to be extracted from cavity <NUM> and inserted into the housing <NUM>.

According to a preferred embodiment, the packing machine <NUM> operates on a double line, namely, it processes two straws <NUM> at a time arranged end to end (namely, axially aligned with one another). In other words, the pick-up conveyor <NUM> has a series of pairs of suction seats (axially aligned with one another) to pick-up two straws <NUM> at a time from the outlet mouth of the hopper <NUM> and the corrugator drum <NUM> has a series of pairs of suction seats (axially aligned with one another) which simultaneously receive two straws <NUM> from the pick-up conveyor <NUM>, simultaneously corrugate two straws <NUM> together with the corrugator device <NUM>, and simultaneously release two straws <NUM> to the bending drum <NUM>. According to a further alternative, the pick-up conveyor <NUM> has a series of suction seats having a length double the length of a straw to pick-up a semi-finished product having a length double that of a straw from the outlet mouth of the hopper <NUM>. In this case, a cutting member can be arranged at the pick-up conveyor <NUM> to cut, with a straight or inclined cut, the semi-finished product into two straws. These two straws will then be transferred to the corrugator drum <NUM> as described above.

In turn, the bending drum <NUM> has a series of pairs of suction seats <NUM> (axially aligned with one another) which simultaneously receive two straws <NUM> from the corrugator drum <NUM>, simultaneously bend two straws <NUM> (operating with two respective pairs of elements <NUM>, <NUM> and <NUM>), and simultaneously release two straws <NUM> to the wrapping drum <NUM>. In turn, the wrapping drum <NUM> has a series of pairs of suction seats <NUM> (axially aligned with one another) which simultaneously receive two straws <NUM> from the bending drum <NUM>, simultaneously produce two wraps <NUM> (operating with a strip <NUM> of wrapping material having double width), and simultaneously transfer two wraps <NUM> to the outlet conveyor <NUM>. In turn, the outlet conveyor <NUM> has a series of pairs of suction seats (axially aligned with one another) which simultaneously receive two wraps <NUM> from the wrapping drum <NUM>.

According to a different embodiment, the packing machine <NUM> operates on a single line, namely, it processes only one straw <NUM> at a time.

According to a further embodiment, the packing machine <NUM> operates on a triple or quadruple line, namely, it processes three or four straws <NUM> at a time arranged end to end (namely, axially aligned with one another).

The embodiments described herein can be combined with each other.

The bending unit described above (essentially formed by the bending drum <NUM> and by the elements <NUM>, <NUM> and <NUM>) has numerous advantages.

Firstly, the bending unit described above allows to operate at a high processing speed (measured as the number of pieces produced in a unit of time) while, at the same time, maintaining a high production quality (namely, without damaging the straws <NUM> during bending).

Claim 1:
A method to bend a straw (<NUM>) comprising the steps of:
causing a bending drum (<NUM>), which is provided with at least one seat (<NUM>) designed to house the straight straw (<NUM>) and with a cavity (<NUM>) arranged at the seat (<NUM>) and radially more on the inside than the seat (<NUM>), to rotate around a rotation axis (<NUM>);
feeding the straight straw (<NUM>) to the seat (<NUM>); and
pushing the straw (<NUM>) into the cavity (<NUM>) by means of the action of a first bending element (<NUM>), which radially moves relative to the seat (<NUM>) for at least partially bending the straw (<NUM>) in a "U"-shape against at least one wall (<NUM>) of the cavity (<NUM>).