Patent Description:
In the prior art, drinking straws are typically made from a continuous tubular element, obtained, for example, by extrusion of PLA and then cut into segments defining the straws which are then sent on for further processing. In particular, the machine that does this comprises a longitudinal feed line followed by the continuous tubular element and by the straws after cutting, until reaching a transfer unit which changes the feed direction of the straws from longitudinal to transverse.

A machine of this type is known, for example, from document <CIT> and is provided with a pneumatic unit which expels the individual straws sideways towards a transverse conveyor.

The machine described above has the disadvantage of requiring a generator for producing blasts of compressed air which, at high production speeds, can be very complicated and subject to faults or frequent maintenance requirements. Moreover, the system is based on blasts of compressed air which are unable to ensure a uniform pushing action on the straws, with the risk of causing unwanted rotation of the straws and creating problems for the conveyor downstream.

In this context, the basic technical purpose of this invention is to provide a machine and a method for making straws to overcome the above mentioned disadvantages of the prior art.

In particular, the aim of this invention is to provide a machine and a method for making straws, characterized by high reliability.

Another aim of the invention is to provide a machine and a method for making straws and to allow the orientation of the straws to be controlled in an optimum manner during the change in their feed direction.

The technical purpose indicated and the aims specified are substantially achieved by a machine and a method for making straws, comprising the technical features described in one or more of the appended claims <NUM>-<NUM>. The invention is described below with reference to the accompanying drawings, which illustrate a non-limiting embodiment of it, in which:.

In the accompanying drawings, the numeral <NUM> denotes in its entirety a machine for making straws in accordance with this invention.

The machine essentially comprises a forming unit <NUM> for forming a continuous tubular element T, a cutting unit <NUM> for cutting the continuous tubular element T into tubular segments <NUM> of predetermined length and, downstream of the cutting unit <NUM>, a transfer unit <NUM> for the tubular segments100, configured for transferring the segments <NUM> from a longitudinal feed direction to a transverse (perpendicular) feed direction.

The forming unit <NUM> is of known type and can make a continuous tubular element T from any material and with any structure. For example, the continuous tubular element T can be made by extrusion of plastic material or from paper material, in the latter case by longitudinally wrapping a single paper web, whether single-layer or multilayer, or by helically wrapping two or more paper webs. It is understood that the structure and material of the continuous tubular element T do not limit this invention. <FIG> shows a solution where the continuous tubular element T is obtained by longitudinally wrapping a continuous web <NUM> unwound from a roll <NUM> and made to advance along a feed direction A.

The cutting unit <NUM> is also made according to known solutions, in particular using one or more rotary blades operating on the continuous tubular element T while it is being advanced longitudinally. The cutting unit <NUM> and the transfer unit <NUM> are distinct units.

Preferably, the segments <NUM> leaving the cutting unit <NUM> and constituting the straws have a length of between <NUM> and <NUM>, more preferably between <NUM> and <NUM>.

With reference to the transfer unit <NUM>, a first embodiment of it is shown in <FIG>, where <FIG> and <FIG> illustrate it with some parts omitted so as to better illustrate inner parts of it.

Looking in more detail, the transfer unit <NUM> comprises a support beam <NUM> is provided with a longitudinal groove <NUM> whose transverse cross section is preferably arcuate in shape and which is intended to feed the segments <NUM> in succession after they have been cut. In a possible embodiment not illustrated, one or more accelerator rollers may be located between the cutting unit <NUM> and the transfer unit <NUM> to accelerate the segments <NUM> so as to space them apart from each other.

Disposed above the support beam <NUM> is a mounting shaft <NUM> which is rotatable about an axis of rotation X parallel to the longitudinal groove <NUM> and on which a plurality of pushing elements <NUM>, axially spaced along the axis X, are mounted. In the embodiment illustrated, there are four pushing elements <NUM> but, depending on requirements, there may be a different number of them, greater than or equal to one.

The mounting shaft <NUM> is rotated about the axis X by means of a rotary actuator M, preferably a servomotor, and this simultaneously sets the pushing elements <NUM> in rotation. The contact portions 8a of the pushing elements <NUM> are disposed in phase with each other in such a way that corresponding contact portions 8a of the pushing elements <NUM> simultaneously impact against different portions of the same segment <NUM>.

Each pushing element <NUM> has a contact portion 8a designed to impact against a segment <NUM> to expel the segment transversely from the groove <NUM> and to deflect the segment <NUM> from the longitudinal feed direction defined by the groove <NUM> to a transverse feed direction, for example, towards a further conveyor or towards a container (not illustrated).

In the embodiment of <FIG>, each pushing element <NUM> has two contact portions 8a on opposite sides of the axis of rotation X, although the number of contact portions 8a may be different, in particular, a number greater than or equal to one.

<FIG> is a detail view showing one of the pushing elements <NUM> used in the embodiment of <FIG>. This pushing element <NUM> comprises a central portion <NUM> and a pair of radial arms <NUM> extending radially away from the central portion <NUM> in diametrically opposite directions and each defining a respective contact portion 8a.

The central portion <NUM> is provided with a radial recess 9a configured for laterally mounting the pushing element <NUM> on the mounting shaft <NUM>, in particular, by transversely inserting the shaft <NUM> into the recess 9a. Further, the mounting shaft <NUM> is provided with a succession of receiving flanges 7a defining respective radial expansions of the mounting shaft <NUM> and each intended for frontally mounting the central portion <NUM> of a corresponding pushing element <NUM>, for example reversibly, using threaded means.

More generally speaking, each pushing element <NUM> has a plurality of radial arms <NUM> angularly distributed around the central portion <NUM>, in accordance with embodiments not illustrated.

In the embodiment illustrated, the axis of rotation X is disposed above the longitudinal groove <NUM>, preferably in a substantially vertical position above the longitudinal groove <NUM>.

Further, each contact portion 8a is flat and is configured and/or oriented in such a way as to be positioned substantially perpendicularly to the (horizontal) top surface of the support beam <NUM> at the instant of impact with a respective segment and/or in such a way that its movement is parallel with the top surface of the support beam <NUM> at the instant of impact with a respective segment <NUM>.

In a variant embodiment not illustrated, the contact portion 8a is configured and/or oriented in such a way as to be inclined upwards at the instant of impact with a respective segment and/or in such a way that its movement has an upwardly directed component at the instant of impact with a respective segment <NUM>, so as to facilitate expulsion of the segment <NUM> from the groove <NUM>.

In the specific embodiment illustrated in the accompanying drawings, each contact portion 8a lies in a plane passing through the axis of rotation X which, in the view of <FIG>, corresponding to the instant of impact against a segment <NUM>, is oriented vertically.

In variant embodiments not illustrated, the axis of rotation X may be disposed below the level of the groove <NUM>, preferably vertically below it, and the contact portions 8a intersect the upper plane of the support beam <NUM> in proximity to the instant of impact against the segment <NUM> and then return below it.

Preferably, the transfer unit <NUM> also comprises at least one upper guide element <NUM> defining, in conjunction with the support beam <NUM>, a preferably horizontal channel <NUM>, with a substantially constant thickness, for guiding the segments <NUM> transversely away from the longitudinal groove <NUM>.

In the specific embodiment, the transfer unit <NUM> comprises a plurality of upper guide elements <NUM> in the form of brackets or plates, whose underside surfaces are parallel to the support beam <NUM> to define an upper guide for the segments <NUM>. The upper guide elements <NUM> are spaced apart from each other along the groove <NUM> and are alternated with the pushing elements <NUM>. Preferably, the transfer unit <NUM> also comprises one or more stop aprons <NUM> facing the support beam <NUM>, more specifically the channel <NUM>, and configured for receiving and stopping the segments <NUM> expelled transversely by the pushing elements <NUM> and also for axially stopping the segments <NUM> by friction. Preferably, the stop apron is made from flexible metallic mesh and hangs by a top portion of it so it is stretched under its own weight.

In the embodiment illustrated and as shown in <FIG>, there is a plurality of stop aprons <NUM> which are juxtaposed and spaced from each other. In a different embodiment, not illustrated, there is only one stop apron <NUM> which faces all the pushing elements <NUM>.

Below the support beam <NUM> there is a chute <NUM> for guiding downwardly the segments <NUM> expelled laterally by the pushing elements <NUM>.

A variant embodiment shown in <FIG> comprises, in addition or alternatively to the stop aprons <NUM>, deformable braking elements <NUM> adapted to at least partly dampen/absorb the longitudinal kinetic energy of the segments <NUM>. For example, the deformable braking elements <NUM> comprise brushes, a metallic or plastic or rubber mesh or elastic metal parts.

The deformable braking elements <NUM> are intended to be intercepted by the segments <NUM> after the segments have been transversely deflected by the pushing elements <NUM>. Looking in more detail, the deformable braking elements <NUM> are alternated with the pushing elements <NUM> and extend downwardly into the channel <NUM> to partly obstruct the channel <NUM> so as to axially brake the segments <NUM>. The deformable braking elements <NUM> are disposed at laterally offset positions, outwards, relative to the groove <NUM>.

In the specific embodiment illustrated in <FIG>, installed between two adjacent pushing elements <NUM>, there is a mounting block <NUM>, which is fixed to the support beam <NUM> or to another fixed structure and on which a stop apron <NUM>, a deformable braking element <NUM> and two upper guide elements are mounted at the axial ends of the mounting block <NUM>. The deformable braking element <NUM> is disposed at an intermediate position between the groove <NUM> and the stop apron <NUM>.

According to an aspect of the invention, not illustrated, the contact portion 8a is made from elastically compliant or resilient material (while the rest of the pushing element is made from a rigid material, in particular, metal or light alloy). The elastically compliant or resilient material is preferably an elastomeric material or a brush portion. More preferably, the contact portion 8a is made in the form of a replaceable insert, applied, for example, using one or more threaded elements.

According to another aspect of the invention, the transfer unit <NUM> also comprises speed variation means to cause the pushing elements <NUM> to rotate at a slower speed in a controlled manner in proximity to the instant of impact between the contact portion 8a and a segment <NUM>. In an embodiment, the speed variation means comprise an electronic control acting on the rotary actuator M. In a different embodiment, the speed variation means comprise a cam transmission (not illustrated), interposed between the rotary actuator M and the pushing elements <NUM>, in particular, between the rotary actuator M and the mounting shaft <NUM>.

<FIG> shows a variant embodiment in which there is a single pushing element <NUM> (provided with two contact portions 8a but there might be any number of these, as described above). This pushing element <NUM> has a contact portion 8a that extends substantially for the full length of the pushing element <NUM>, in particular for a length of at least <NUM> so as to come into contact with a preponderant portion of a segment <NUM>. The contact portion 8a shown is in the form of a brush but it might be made from another compliant material or even a rigid material.

The transfer unit <NUM> described above may define a rejection unit for rejecting the segments <NUM> and, in such a case, the longitudinal groove <NUM> extends further downstream of the transfer unit <NUM> as far as an axial outfeed unit for the segments <NUM>.

Alternatively, the transfer unit defines the outfeed unit of the segments <NUM>. In such a case, the longitudinal groove may extend further downstream of the transfer unit <NUM> as far as a rejection unit for rejecting segments <NUM> that are defective or intended for inspection or, alternatively, a transverse rejection unit for rejecting the segments <NUM> upstream of the transfer unit <NUM>. This invention lends itself to numerous modifications without departing from the scope of the inventive concept.

In particular, the longitudinal groove <NUM> is not an essential feature for the purposes of the invention. It may therefore be omitted and the segments <NUM> guided longitudinally directly onto a flat upper surface of the support beam <NUM> without appreciably altering the correct axial movement of the segments <NUM>.

<FIG> show two different embodiments where the longitudinal groove <NUM> is not present and where, preferably, the segments <NUM> are guided temporarily by the selfsame pushing elements <NUM> (or the single pushing element <NUM> in the case of the embodiment of <FIG>).

In these two embodiments, the pushing element <NUM> itself, and in particular, its end portion, in conjunction with other parts, defines means for longitudinally guiding the segments <NUM>.

Looking in more detail, in the embodiment of <FIG>, the support beam <NUM> is provided with a raised edge or step 5a at the rear of it (that is, opposite of the transverse outfeed direction of the segments <NUM>) defining a rear stop for the segments <NUM> and preferably having a curvature radius substantially equal to the radius of the segments <NUM>. In this configuration, the pushing element <NUM> (or each pushing element <NUM>) can adopt a guiding configuration for the segments <NUM>, defined by an angular position about the axis X ahead of the raised edge or step 5a (that is to say angularly offset forwardly relative to the impact configuration of <FIG>) such that a segment <NUM> is guided, at the back, by the raised edge or step 5a and, at the front, by a rear surface of the pushing element <NUM>, the raised edge or step 5a and the rear surface of the pushing element <NUM> defining the aforementioned guide means. This configuration (<FIG>) is, for example, set during machine start-up and is maintained stably so that one or more segments <NUM> to be rejected are conveyed longitudinally without being deflected transversely. On reaching a predetermined instant or following a command, the pushing element <NUM> is set in rotation to laterally deflect the segments <NUM> according to the operation described above (<FIG>).

In the embodiment of <FIG>, the support beam <NUM> is smooth (that is to say, without raised edges or guide recesses in the zone of longitudinal transit of the segments <NUM>) and the segments <NUM> are longitudinally guided solely by the pushing element <NUM> which, at its free end, has a recess 8b facing towards the support beam <NUM> and defining, in conjunction with the support beam <NUM>, a passage (or tunnel) for laterally retaining the segments <NUM> so that the segments <NUM> can slide longitudinally in a guided manner. Furthermore, the depth of the recess 8b is preferably such as to also guide the segments <NUM> vertically. More preferably, the recess 8b has an arcuate inside surface whose diameter, in particular, is substantially the same as the diameter of the segments <NUM>. Moreover, the side walls radially terminating the recess 8b may be parallel to each other.

Claim 1:
A machine for making straws, comprising:
- a forming unit (<NUM>) for forming a continuous tubular element (T);
- a cutting unit (<NUM>) for cutting the continuous tubular element (T) into tubular segments (<NUM>) of predetermined length as the continuous tubular element (T) is fed longitudinally;
- a transfer unit (<NUM>) for the tubular elements (<NUM>), located downstream of the cutting unit (<NUM>) and configured for transferring the segments (<NUM>) from a longitudinal feed direction to a transverse feed direction;
characterized in that the transfer unit (<NUM>) comprises a support beam (<NUM>) for the segments (<NUM>) and at least one pushing element (<NUM>) which is rotatable about an axis (X) parallel to the longitudinal feed direction and which has a contact portion (8a) designed to impact against each segment (<NUM>) supported by the support beam (<NUM>) to deflect the segment (<NUM>) from the longitudinal feed direction to the transverse feed direction.