WO2021140383A1

WO2021140383A1 - Device and method for folding web material in a plant and process for producing layered composite articles

Info

Publication number: WO2021140383A1
Application number: PCT/IB2020/061936
Authority: WO
Inventors: Davide Viola; Marco Viola; Andrea VIOLA
Original assignee: M.D. Viola Macchine S.R.L.
Priority date: 2020-01-09
Filing date: 2020-12-15
Publication date: 2021-07-15
Also published as: IT202000000259A1

Abstract

A device for folding web material in a plant for producing pull-up diapers, comprises a folder (15) arranged between a first guide and a second guide of a web material (6). The folder (15) comprises an elongated edge (19) which extends from the first guide towards the second guide in a receiving plane and away from a feeding plane, in order to progressively move away an intermediate section (16) of the web material (6) from the feeding plane and folding the web material (6) in two while it travels from the first guide towards the second guide. A motorized conveyor (22) is arranged below the folder (15) and has a movable surface facing the elongated edge (19) and is configured to accompany and/or drag the intermediate section (16) of the web material (6) along said elongated edge (19).

Description

Title

“Device and method for folding web material in a plant and process for producing layered composite articles”

DESCRIPTION

Field of the invention

The object of the present invention is a device and a method for folding web material in a plant and process for producing layered composite articles. In particular, the present invention is situated in the field of production of layered composite articles formed by sheets of fabric and/or nonwoven fabric (NWF) and possible further elements such to confer the desired properties (such as for example: impermeability, absorption, breathability, elasticity, etc.) to the articles. Such articles can for example be clothing garments. Preferably but not exclusively, the present invention is situated in the field of production lines for producing hygienic-sanitary articles, in particular diapers and adult diapers, whose packaging is executed starting from different semifinished products, including webs of material wound in a reel, such as polyethylene, nonwoven fabric, cellulose cotton wool (tissue).

State of the art

In the production lines of hygienic articles, the material webs are unwound from reels in order to be subsequently fed to processing stations which provide for coupling them together and possibly to other materials, in order to form a semifinished product constituted by a layered composite web.

In the manufacturing of pull-up diapers, for example, it is known to package a semifinished product constituted by a layered composite web which is subsequently shaped, in order to obtain a series of open diapers that are joined to each other. The layered composite web is then longitudinally folded in two and welded, so as to obtain a series of closed diapers that are joined to each other. The abovementioned composite web is then cut in order to obtain the single diapers. Such operations are carried out while the layered composite web continuously advances along a feeding path in a plant for producing the abovementioned diapers. It is known to execute the longitudinal folding of the layered composite web by means of a folder defined by a tube or by a flattened body which is arranged vertically between a first guide, defining a horizontal feeding plane for feeding layered composite web, and a second guide, defining a vertical receiving plane for receiving layered composite web, in which the second guide is positioned downstream of the first guide with respect to a feed direction of said layered composite web.

The layered composite web is made to advance from the first guide towards the second guide and is kept under tension at opposite longitudinal edges thereof and longitudinally dragged. While the layered composite web advances, a center line longitudinal section (corresponding to the crotch of the pull-up diapers) of the layered composite web slides against a lower fixed edge of the tube or of the flattened body and is progressively moved downward by the abovementioned lower fixed edge while the opposite longitudinal edges (corresponding to the waist of the pull-up diapers) are maintained at a higher height and are moved close to each other until they touch. In this manner, the layered composite web is folded in half along the center line longitudinal section thereof.

WO2019/215607A1 illustrates an apparatus for folding a continuous web fed into a plant for producing hygienic absorbent articles and intended to be folded, according to a V or U shape, along a longitudinal folding line parallel to a feeding line of the continuous web.

DE2330513A1 illustrates a folder of sheets, in which a paper sheet is folded by means of belts and drums.

US2010050411A1 illustrates a method for producing an absorbent article comprising a process for folding a sheet in two after a step of forming openings for the legs.

US3398656A illustrates a guide system for a wrapping machine.

US2016228303A1 illustrates a device for producing a disposable wearable article. The device comprises a joining/cutting unit, part of a line for the continuous transport of a sheet and configured for joining parts of the sheet folded in two placed at opposite sides of an absorbent element and then for cutting the joined parts, and a pressing unit arranged upstream of the joining/cutting unit with respect to a transport direction. Object of the invention

The Applicant has observed that, during the above-illustrated folding, the center line section tends to remain behind with respect to the opposite longitudinal edges, giving rise to a folded layered composite web that is deformed. In particular, in the case of the production of pull-up diapers, the crotch of each diaper is not aligned with respect to the respective waist and hence each diaper is deformed.

The Applicant has also observed that such deformation can lead to executing, in the joining/welding station(s) placed more downstream, junctions/welds that are defective since the zones that must be mutually joined (corresponding for example to the sides of each diaper) are not correctly aligned.

The Applicant has also observed that such defects can lead to making layered composite articles that are defective (e.g. pull-up diapers that break at the junctions/welds while they are worn) and/or which also produce a non-attractive appearance since they are for example asymmetric.

The Applicant has also observed that the abovementioned center line section that slides against the lower fixed edge can be ruined due to such sliding, giving rise to further defects in the finished layered composite articles.

In such context, the Applicant has therefore set the objective of proposing a device and a method for folding web material in a plant for producing layered composite articles, which first of all allow preventing or limiting the deformation of the folded web material and hence improving the quality of the layered composite articles obtained therefrom.

The Applicant, has also set the object of proposing a device and a method for folding web material which allow improving the quality of the junctions, preferably welds, executed on said web material.

The Applicant has also set the object of proposing a device and a method for folding web material which allow reducing the sliding of the web material.

The Applicant has also set the object of proposing a device and a method for folding web material which can be easily adapted to different sizes/characteristics of the produced articles.

The Applicant has also set the object of proposing a device for folding web material which, in addition to the above-indicated objectives, is also structurally simple, inexpensive and easy to manage and maintain. Summary of the invention

The Applicant has found that such objectives and further objects can be obtained by means of a device and a method in accordance with the present invention, of the type claimed in the enclosed claims and/or described in the following aspects. In particular, the Applicant has found that such objectives and further objects can be obtained by coupling, to the lower fixed edge, a movable surface which faces towards said lower fixed edge and is moved together with an intermediate longitudinal section, preferably with the center line longitudinal section, of the web material that lies between the lower fixed edge and said movable surface, so as to accompany it/drag it.

In particular, in accordance with a first aspect, the present invention relates to a device for folding web material in a plant for producing layered composite articles, preferably pull-up diapers, comprising: a first guide defining a feeding plane for feeding a web material; a second guide defining a receiving plane for receiving the web material, in which the second guide is positioned downstream of the first guide with respect to a feed direction of said web material, in which the receiving plane is substantially orthogonal to the feeding plane; a folder arranged between the first guide and the second guide and comprising an elongated edge extending between the first guide and the second guide along said feed direction; in which the elongated edge extends from the first guide towards the second guide in the receiving plane and away from the feeding plane, in order to progressively move away an intermediate section of the web material from the feeding plane and folding said web material in two while it travels from the first guide towards the second guide; a motorized conveyor arranged along the elongated edge, having a movable surface facing the elongated edge, movable from the first guide towards the second guide and configured to accompany and/or drag along said elongated edge the intermediate section of the web material lying between the elongated edge and the movable surface.

In accordance with a second aspect, the present invention relates to a method for folding web material in a process for producing layered composite articles, comprising: feeding a web material along a feed direction and from a first guide defining a feeding plane for feeding the web material towards a second guide defining a receiving plane for receiving the web material, in which the second guide is positioned downstream of the first guide with respect to the feed direction, in which the receiving plane is substantially orthogonal to the feeding plane; moving an intermediate section of the web material along the receiving plane and away from the feeding plane and from opposite longitudinal edges of said web material while it travels from the first guide towards the second guide so as to fold said web material in two; wherein moving the intermediate section also comprises: accompanying and/or dragging the intermediate section of the web material from the first guide towards the second guide, interposing it between an elongated edge of a folder and a movable surface of a conveyor facing the elongated edge; wherein, optionally, the folder and the conveyor are part of the device in accordance with the first aspect or with one or more of the following aspects.

In accordance with one aspect, the present invention relates to a plant for producing layered composite articles, comprising: a plurality of reel holder for respective reels of material webs (such as for example polyethylene, nonwoven fabric, cellulose cotton wool); a plurality of transport and transmission devices defining respective paths for said material webs; a plurality of joining devices acting along said paths in order to join together said material webs and possible further elements and form a layered composite web; at least one cutting device for cutting said layered composite web and forming layered composite articles; wherein the plant also comprises the device in accordance with the first aspect and/or in accordance with one or more of the following aspects; wherein the web material folded by said device is one of the material webs and/or the layered composite web. In accordance with one aspect, the present invention relates to a process for producing layered composite articles, comprising: feeding material webs (such as for example polyethylene, nonwoven fabric, cellulose cotton wool) along respective paths; associating and joining together said material webs and possibly further elements in order to form a layered composite web; cutting said layered composite web in order to form layered composite articles; wherein the process also comprises the method in accordance with the second aspect and/or in accordance with one or more of the following aspects; wherein the web material of said method is one of the material webs and/or the layered composite web.

With intermediate section it is intended a longitudinal section situated between the two opposite longitudinal edges. Such intermediate section can coincide, or not coincide, with a center line section of the web material equidistant from the two longitudinal edges. If said intermediate section coincides with the center line section, then the web is folded in half and the two longitudinal edges are mutually aligned, i.e. placed at a same height so as to mate after the folding. If said intermediate section is different from the center line section, then the two longitudinal edges are positioned at different heights after the folding.

The Applicant has verified that the solution according to the invention first of all allows preventing or at least limiting the deformation of the folded web material and hence of improving the quality of the layered composite articles obtained therefrom. The Applicant has in fact verified that the motorized conveyor prevents the intermediate section from remaining behind with respect to the opposite longitudinal edges of the web material. Indeed, the motorized conveyor is moved together with the intermediate section and accompanies it/drags it towards the second guide, maintaining the web material non-deformed.

The Applicant has also verified that the dragging of the intermediate section is ensured by the fact that such intermediate section is interposed and retained between the elongated edge and the movable surface. The pressure exerted by these two elements is such to ensure that the intermediate section is moved integral with the movable surface, i.e. to prevent said intermediate section from moving with respect to the movable surface. The Applicant has in particular verified that the solution according to the invention allows precisely aligning the zones of the web material that must be mutually joined, and hence making junctions, preferably welds, that are correct and high quality. The Applicant has also verified that the solution according to the invention allows reducing the sliding of the web material along the production path. The Applicant has thus verified that the solution according to the invention allows more generally improving the quality, also the appearance, of the layered composite articles produced.

The Applicant has also verified that the solution according to the invention can be easily adapted to articles of different size and with characteristics different from each other.

The Applicant has also verified that the mechanical solution according to the invention is also structurally simple, inexpensive and easy to manage and maintain. Further aspects of the invention are described hereinbelow.

In one aspect, the feeding plane is a substantially horizontal plane.

In one aspect, the feeding plane is tilted with respect to a horizontal plane by an angle comprised between 0° and 15°.

In one aspect, the receiving plane is a substantially vertical plane.

In one aspect, the motorized conveyor lies below the folder.

In one aspect, the motorized conveyor comprises a conveyor belt extending at least in part along the elongated edge.

In one aspect, the movable surface is an upper branch of the conveyor belt.

In one aspect, an upper surface of the conveyor belt is configured for being placed in contact with the intermediate section of the web material and being moved together with said intermediate section.

In one aspect, a distance between the movable surface and the elongated edge is adjustable/settable, by moving the folder and the motorized conveyor with respect to each other.

In one aspect, an interspace is delimited between the movable surface and the elongated edge for the passage of the intermediate section.

In one aspect, a thickness of said interspace is adjustable/settable.

In one aspect, a tension of the belt is settable/adjustable.

In one aspect, the conveyor belt is made of rubber or polyurethane.

In one aspect, said upper branch of the conveyor belt is movable from the first guide towards the second guide.

In one aspect, the conveyor belt extends along a closed path lying substantially in the receiving plane.

In one aspect, the motorized conveyor comprises a plurality of pulleys.

In one aspect, the conveyor belt is wound on said pulleys. In one aspect, at least one of said pulleys is motorized.

In one aspect, a motor is connected to at least one of the pulleys, in order to rotate said at least one pulley and move the conveyor belt.

In one aspect, the conveyor belt is toothed and teeth of the belt are engaged with the pulleys.

In one aspect, the conveyor belt is a flat, polycord, trapezoidal belt.

The use of the conveyor belt allows preventing the ruining of the web material that lies in contact therewith.

In one aspect, the elongated edge is directed downward.

In one aspect, the elongated edge has a curvilinear progression.

In one aspect, said curvilinear progression has a convexity directed downward.

In one aspect, the folder comprises a bar, optionally curved, mainly extended in the receiving plane, in which the elongated edge is a lower edge of said bar.

In one aspect, the bar is a metal rod.

In one aspect, a distance of the elongated edge from the opposite longitudinal edges of the web material, measured in the receiving plane, increases starting from the first guide towards the second guide.

In one aspect, a first end of the elongated edge is close to the first guide and a second end of the elongated edge is close to the second guide.

In one aspect, a first end of the elongated edge faces the first guide.

In one aspect, the first guide comprises a first transport surface parallel to the feeding plane.

In one aspect, the first transport surface is motorized.

In one aspect, the web material is arranged on the first transport surface.

In one aspect, the first guide comprises a first roller, in which the first transport surface is a radially outer surface of the first roller.

In one aspect, the first roller has a rotation axis parallel to the feeding plane.

In one aspect, the first guide comprises a first conveyor belt, in which the first transport surface is a surface of said first conveyor belt.

In one aspect, the second guide comprises second transport surfaces that are opposite and parallel to the receiving plane.

In one aspect, the second transport surfaces are motorized.

In one aspect, the web material folded in two, preferably in half, is arranged between the second transport surfaces. In one aspect, a second end of the elongated edge is arranged between the second transport surfaces.

In one aspect, the second guide comprises a pair of opposite second rollers, in which the second transport surfaces are radially outer surfaces of the second rollers. In one aspect, the opposite second rollers have rotation axes parallel to the receiving plane.

In one aspect, the second guide comprises a pair of second conveyor belts, in which the second transport surfaces are surfaces of said second conveyor belts.

In one aspect, while the opposite longitudinal edges of the web material advance in the feed direction, the intermediate section moves integral with the motorized conveyor, preferably with the conveyor belt, preferably with the upper branch of the conveyor belt arranged along the elongated edge.

In one aspect, while the opposite longitudinal edges of the web material advance in the feed direction, the intermediate section is moved/dragged by the motorized conveyor along the elongated edge, preferably by the conveyor belt, preferably by the upper branch of the conveyor belt arranged along the elongated edge.

In one aspect, while the opposite longitudinal edges of the web material advance in the feed direction, said opposite longitudinal edges move close to each other, preferably up to touching.

In one aspect, moving close the opposite longitudinal edges of the web material comprises: associating sections to be mutually joined, preferably by means of welding.

In one aspect, while the opposite longitudinal edges of the web material advance in the feed direction, said longitudinal edges are maintained at a higher height than the intermediate section.

In one aspect, provision is made for adjusting a dragging speed of the intermediate section, preferably along the elongated edge.

In one aspect, provision is made for adjusting a speed of the motorized conveyor, preferably of the conveyor belt, preferably of the upper branch of the conveyor belt arranged along the elongated edge.

In one aspect, the speed of the motorized conveyor is adjustable, manually or automatically.

In one aspect, the device for folding web material comprises an electronic control unit operatively connected at least to the motor of the motorized conveyor and preferably to the motorized first transport surface and to the motorized second transport surfaces.

In one aspect, provision is made for setting the speed of the motorized conveyor at the start of a production batch.

In one aspect, provision is made for setting or adjusting the speed of the motorized conveyor as a function of a speed of the plant.

In one aspect, provision is made for setting or adjusting the speed of the motorized conveyor as a function of the speed of the motorized first transport surface and/or of the motorized second transport surfaces.

In one aspect, provision is made for setting or adjusting the speed of the motorized conveyor as a function of characteristics/sizes of the layered composite articles to be produced.

In one aspect, the web material is a layered composite web.

In one aspect, the layered composite articles are pull-up diapers.

In one aspect, the web material comprises a plurality of layered composite articles joined together in series and, preferably, configured for attaining pull-up diapers.

In one aspect, the intermediate section, preferably center line, of the layered composite web corresponds with a crotch of the pull-up diapers.

In one aspect, the opposite longitudinal edges of the layered composite web correspond with the waist of the pull-up diapers.

In one aspect, the sections to be mutually joined correspond with the sides of each pull-up diaper.

In one aspect, actively accompanying and/or dragging the intermediate section comprises: adjusting or maintaining an alignment between the waist and the crotch of the pull-up diapers while the web material is folded.

In one aspect, actively accompanying and/or dragging the intermediate section comprises: adjusting or maintaining a relative position between the waist and the crotch of each of the pull-up diapers while the web material is folded.

In one aspect, the folder can be oriented around an adjustment axis arranged in proximity to the second guide and lying in the receiving plane, in order to change a position of the first end of said elongated edge with respect to the first guide, so as to adjust a mutual position, preferably a mutual alignment, of the opposite longitudinal edges at the second guide. In one aspect, provision is made for orienting the folder around an adjustment axis arranged in proximity to the second guide and lying in the receiving plane, in order to change a position of a first end of said elongated edge with respect to the first guide so as to adjust a mutual position, preferably a mutual alignment, of the opposite longitudinal edges after the folding.

In one aspect, the adjustment axis forms, with a vertical direction, an angle comprised between 0° and 15°.

In one aspect, the folder can be oriented around the adjustment axis for an angle comprised between +/-15°, preferably comprised between +/-10°, with respect to an average position corresponding to a middle point of the first guide.

In one aspect, an actuator is connected to the folder, preferably to the bar, and is configured to move said folder around the adjustment axis.

In one aspect, at least one position sensor is configured to detect a relative position of the opposite longitudinal edges of the web material.

In one aspect, said at least one position sensor comprises two position sensors, each position sensor being arranged on a respective side of the folder in order to spot a respective longitudinal edge of the folded web material.

In one aspect, the electronic control unit is configured or programmed for executing the following procedure: receiving, from said at least one position sensor, at least one signal correlated with the relative position of the opposite longitudinal edges of the web material; driving the actuator as a function of said at least one signal up to positioning the opposite longitudinal edges in a desired position, preferably up to mutually aligning the opposite longitudinal edges.

In one aspect, provision is made for detecting a non-alignment between the opposite longitudinal edges and orienting the folder up to eliminating said non-alignment or up to obtaining a predetermined and desired non-alignment.

In one aspect, provision is made for detecting a non-alignment between the opposite longitudinal edges and orienting the folder up to obtaining a predetermined and desired non-alignment.

In one aspect, the motorized conveyor can be oriented, optionally around the adjustment axis.

In one aspect, the motorized conveyor is transversely movable with respect to the feed direction. In one aspect, the motorized conveyor is rigidly connected to the folder in order to move together with said folder around the adjustment axis.

In one aspect, the motorized conveyor is movable around the adjustment axis and/or transversely with respect to the feed direction, independent of the folder. In one aspect, an auxiliary actuator is connected to the motorized conveyor and is configured to move said motorized conveyor around the adjustment axis and/or transversely with respect to the feed direction.

In one aspect, the motorized conveyor is fixed and the movable surface has a width such that said movable surface always faces the elongated edge for every orientation/position of the folder around the adjustment axis.

The Applicant has verified that, by moving the first end of the elongated edge of the folder with respect to the first guide and therefore also with respect to the intermediate section, preferably to the center line of the section of web material that is arranged on the first guide, it is possible to compensate for the movement of the intermediate section of said web material, due to deformations and/or slides of the same, more downstream, so as to mate said intermediate section with the elongated edge at the second guide and thus ensure the desired mutual position, preferably the mutual alignment, of the opposite longitudinal edges of the web material downstream of the folder. In other words, a rotation of the folder around the adjustment axis results in a relative movement, in planes parallel to the receiving plane, of the opposite longitudinal edges of the web material folded in two, preferably in half.

The motorized conveyor is capable of exerting the dragging action thereof with any orientation of the folder. Further characteristics and advantages will be more evident from the detailed description of a preferred but non-exclusive embodiment of a device and of a method for folding web material in a plant for producing layered composite articles, in accordance with the present invention. Brief description of the drawings

Such description will be set forth hereinbelow with reference to the enclosed drawings, provided only as a non-limiting example, in which:

- figure 1 shows a schematic view of a plant for producing layered composite articles according to the present invention; - figure 2A shows, in a side view, several elements of a station of the plant of figure 1 coupled with a web material according to one embodiment;

- figure 2B is a top view of the station of figure 2A;

- figure 3A illustrates the elements of figure 2A according to a different embodiment;

- figure 3B is a top view of the station of figure 3A;

- figure 4 schematically illustrates a step of folding the web material executed in the station of figures 2 and 3;

- figures 5 and 6 illustrate respective folding configurations of the web material executed in the station of figures 2 and 3;

- figure 7 is a flow diagram of the method according to the present invention.

Detailed description of preferred embodiments of the invention With reference to the enclosed figures, reference number 1 overall indicates a manufacturing plant for producing layered composite articles 2. The plant 1 , illustrated as preferred embodiment, is configured for producing pull-up diapers 2. In other non-illustrated embodiments, the plant 1 can be configured for producing other types of hygienic-sanitary articles or clothing articles or accessories.

In the plant 1 , the packaging of the abovementioned layered composite articles 2 is executed starting from different semifinished products, including material webs 3 wound in reels 4, such as for example polyethylene, nonwoven fabric, cellulose cotton wool (tissue), etc..

The material webs 3 are continuously fed through the plant 1 along respective paths and are joined, shaped, adapted and cut, etc., in order to give rise to the abovementioned layered composite articles 2.

In the schematic example illustrated in figure 1 , the plant 1 comprises a first sector 5 along which the material webs 3 are joined together to form a continuous semifinished product constituted by a layered composite web 6 fed along a transport direction “F”. The layered composite web 6 is rotated 90° while it advances towards a second sector 7 in which it is cut/shaped. In a third sector 8, the layered composite web 6 is folded in two along a longitudinal line and then, in a fourth sector 9, welds are executed and the single articles/diapers 2 are separated from each other.

The plant 1 comprises a plurality of reel holders 10 for the respective reels 4 of material webs 3. The first sector 5 is provided with transport and transmission devices which define respective paths for said material webs 3 and joining/gluing devices acting along said paths in order to join together said material webs 3, and with further elements and in order to form the layered composite web 6. The second sector 7 comprises transport and transmission devices for the layered composite web 6 and cutting and shaping devices. The third sector 8 comprises a device 11 for folding web material, illustrated in detail hereinbelow, and one or more welding stations. The fourth sector 9 comprises at least one cutting device configured to cut said folded layered composite web 6 and separate the layered composite articles 2 (pull-up diapers) from each other. The layered composite web 6 coming from the second sector 7 and directed towards the third sector 8 is constituted by a plurality of open pull-up diapers 2, already shaped following the leg opening operation, i.e. for creating openings for the legs. The layered composite web 6 coming from the third sector 8 and directed towards the fourth sector 9 is constituted by the plurality of pull-up diapers 2 that are closed and welded at the sides but still joined in series to each other. The following are visible: the dashed lines 100 (figure 1 and 4) along which will be cut in order to separate them, the crotch 200 and the waist 300 of each diaper 2. The dashed lines 100 also indicate the zones welded at the sides of each diaper 2.

The device for folding web material 11 (figure 2A) comprises a first guide defined by a first roller 12 rotatable around a horizontal rotation axis “X-X” thereof and preferably connected to a motor, not illustrated and configured in order to make it rotate around said rotation axis “X-X”. An upper section of a radially outer surface of the first roller 12 defines a first transport surface for the layered composite web 6 coming from the second sector 7. The layered composite web 6 is partially wound on the abovementioned radially outer surface of the first roller 12.

In an alternative embodiment, not illustrated, the first guide can comprise a first conveyor belt partially wound around the first roller 12.

A second guide comprising a pair of second opposite conveyor belts 13 wound on respective opposite second rollers 14 (more visible in figure 4) is situated downstream of the first roller 12 and is spaced therefrom. The second rollers 14 are preferably motorized and rotate around respective rotation axes Ύ-U” lying in vertical planes. Internal branches of the second conveyor belts 13 define second transport surfaces for the layered composite web 6. The rotation axes “Y-Y” of the second rollers 14 are tilted with respect to a vertical direction by an angle of about 5°, so that the second conveyor belts 13 are moved along a feed direction “V” tilted by about 5° with respect to a horizontal direction.

In an embodiment variant, not illustrated, the conveyor belts 13 are absent and the second transport surfaces are radially outer surfaces of the second rollers 14. The second guide is therefore placed downstream of the first guide with respect to the feed direction “V” of the layered composite web 6.

The first guide defines a feeding plane for feeding the layered composite web 6 that leaves the first roller 12. Such feeding plane is tilted by the abovementioned angle of about 5° and it is also the plane in which the layered composite web 6 lies, immediately downstream of the first roller 12. The rotation axis “X-X” of the first roller 12 is parallel to the feeding plane.

The second guide defines a receiving plane for receiving the layered composite web 6. Such receiving plane is vertical and is parallel to and interposed between the second transport surfaces of the second conveyor belts 13. The receiving plane is therefore orthogonal to the feeding plane.

A folder 15 is arranged between the first guide and the second guide and is configured for folding in two the layered composite web 6 along an intermediate section thereof. In the illustrated non-limiting embodiment, the folder 15 is arranged between the first guide and the second guide and is configured for folding in half the layered composite web 6 along a longitudinal center line section 16 thereof and in order to move opposite longitudinal edges 17 of said layered composite web 6 close to each other while the layered composite web 6 continuously travels from the first guide towards the second guide along the abovementioned feed direction “V”. As is visible in figures 2A, 2B, 3A, 3B and 4, the layered composite web 6 lies open in the feeding plane when it is situated just downstream of the first roller 12 and is folded in two when it is situated between the second transport surfaces of the second conveyor belts 13.

The folder 15 comprises a curved bar 18 defined for example by a tube or by a metal rod. The curved bar 18 is situated in a vertical plane, i.e. substantially in the receiving plane.

The curved bar has a lower elongated edge 19 thereof which is extended between the first guide and the second guide and has a first end 20 close to the first guide and a second end 21 close to the second guide. The elongated edge 19 has a curvilinear progression with a convexity directed downward. The first roller 12 lies in part below the first end 20 of the elongated edge 19 and such first end 20 faces the radially outer surface of the first roller 12. The second end 21 of the elongated edge 19 terminates between the second rollers 14.

As is visible in figures 2A and 3A, the curved bar 18 has a first part, close to the first end 20, with a greater curvature which extends downward, followed by a second part with smaller curvature and by a third substantially rectilinear part that terminates in the second end 21 . The elongated edge 19 therefore extends from the first guide towards the second guide in the receiving plane and progressively downward, i.e. away from the feeding plane. A distance of the elongated edge 19 from the opposite longitudinal edges 17 of the web 6, measured in the receiving plane, increases starting from the first guide towards the second guide.

A motorized conveyor 22 is positioned below the curved bar 18 and is arranged along the elongated edge 19. The motorized conveyor 22 comprises a conveyor belt 23, e.g. made of rubber or polyurethane, wound on pulleys 24. The pulleys 24 (e.g. three as in figure 2A) are provided with teeth. The conveyor belt 23 is for example toothed and teeth of said belt 23 are engaged with the pulleys 24. Other types of belts can be used, for example flat belts, polycord, trapezoidal belts etc..

The conveyor belt 23 extends along a closed path lying substantially in the receiving plane. An upper branch 25 of the conveyor belt 23 is arranged along the elongated edge 19 and faces the elongated edge 19.

One of the pulleys 24 is motorized, i.e. is connected to a motor 26, in order to rotate said pulley 24 and move the conveyor belt 23 along the closed path. A motion direction of the conveyor belt 23 along the closed path is such to move the upper branch 25 from the first guide towards the second guide.

The upper branch 25 defines a movable surface facing the elongated edge 19 which is instead fixed, in the sense that it does not slide along the feed direction V. The movable surface is configured to accompany and/or drag, along said elongated edge 19, the intermediate section of the layered composite web 6 while said layered composite web 6 lies between the elongated edge 19 and the movable surface. The intermediate section is gripped between the elongated edge 19 and the upper branch 25 and dragged by making it slide on the elongated edge 19. The pressure exerted by these two elements (elongated edge 19 and upper branch 25) is such to ensure that the intermediate section is moved integral with the movable surface, i.e. it is such to prevent said intermediate section from sliding with respect to the movable surface.

For such purpose, provision is made to adjust a distance between the upper branch 25 and the elongated edge 19 of the curved bar 18 and/or adjust a tension of the conveyor belt 23, in particular of the upper branch 25 of said conveyor belt 23. For example, devices can be provided that are adapted to move the folder 15 and the motorized conveyor 22 with respect to each other. In this manner, it is possible to adjust a thickness of an interspace delimited between the movable surface and the elongated edge 19. In the embodiment illustrated in figures 2A and 3A, the motor 26 is mounted on a fixed frame 27 of the plant 1 defined by a vertical wall. The folder 15 is spaced from said vertical wall and the motor 26 is connected to the pulley 24 placed below the first end 20 of the elongated edge 19 by means of a Cardan shaft 28 (only partially visible in figure 2B); such shaft 28 extends from the motor 26 and from said vertical wall up to the pulley 24.

The folder 15 is hinged to and hung from a support 29 around an adjustment axis “K-K”. The support 29 is a bar which is extended overhanging from the vertical wall and carries a pivot, in order to rotatably connect the folder 15, placed at a terminal end thereof. The folder 15 comprises an arm 30 which has one end integrally connected to the curved bar 18 and an opposite end hinged to said support 29 around the adjustment axis “K-K”. The arm 30 has an overturned L shape and a lower end of said arm 30 is joined to the curved bar 18.

The adjustment axis “K-K” passes in proximity to the second end 21 of the elongated edge 19, is orthogonal to the feed direction “V” and lies in a vertical plane, i.e. in the receiving plane. The adjustment axis “K-K” forms an angle of about 5° with a vertical direction.

The folder 15 can be oriented around the abovementioned adjustment axis “K-K”, in order to change a position of the first end 20 of said elongated edge 19 with respect to the first roller 12, so as to adjust a mutual alignment of the opposite longitudinal edges 17 at the second conveyor belts 13.

An actuator 31 is connected to the curved bar 18 and is configured to move the folder 15 around the adjustment axis “K-K”. The actuator 31 is situated between the vertical wall and the curved bar 18. In particular, the actuator 31 is a linear actuator (e.g. electric of screw/nut screw, pneumatic or hydraulic type) and has a rod 32 provided with one end 33 hinged to the folder 15 (or to an element integral with the folder 15) and with an opposite end 34 hinged to the fixed frame 27 (or to an element integral with the fixed frame 27). The end 33 hinged to the folder 15 is situated at the first end 20 of the elongated edge 19, i.e. at the Cardan shaft 28.

The travel of the rod 32 is such to allow orienting the folder 15 around the adjustment axis “K-K” by an angle “a” comprised between +/- 15°, preferably comprised between +/-10°, with respect to an average position in which the curved bar 18 is parallel to the wall 27 and the first end 20 of the elongated edge 19 faces a middle point of the first roller 12, i.e. to the center line section 16 of the web segment 6 placed on the first roller 12.

The motorized conveyor 22 of figures 2A and 2B is fixed in the sense that it cannot be oriented as occurs for the folder 15. The conveyor belt 23 of the motorized conveyor 22 of figures 2A and 2B has (figure 2B) a width Li, measured orthogonally to the receiving plane, such that the upper branch 25 always faces, for the entire extension thereof, the elongated edge 19 of the curved bar 18 even when such curved bar 18 is rotated by the maximum travel, whether in clockwise or counter clockwise sense. For example, such width Li is 30 - 50 cm.

In the embodiment variant of figures 3A and 3B, the motorized conveyor 22 is rigidly constrained to the folder 15 in order to move together with said folder 15 around the adjustment axis K-K by means of the single actuator 31. In such situation, a width l_2 of the conveyor belt can be more limited, e.g. 10 - 15 cm. In this embodiment, the arm 30 carries both the curved bar 18 and the motorized conveyor 22.

In other embodiment variants, not illustrated in the enclosed figures, the motorized conveyor 22 can be oriented around the abovementioned adjustment axis K-K independently with respect to the folder 15, for example by means of a dedicated actuator different from the actuator 31 of the folder 15.

In other embodiment variants, not illustrated in the enclosed figures, the motorized conveyor 22 can for example be laterally translated, i.e. transversely with respect to the feed direction, instead of rotated.

In all of the above-described embodiments, the motorized conveyor 22 is capable of exerting the dragging action thereof on the longitudinal center line section 16 whatever the orientation of the folder 15.

The Cardan shaft 28 allows the folder 15 to oscillate, as illustrated, around the adjustment axis “K-K” due to a slidable coupling between two parts of the same shaft 28 (not illustrated in detail in figures 2A and 2B). Such coupling is for example of splined type in order to prevent the rotation between said two parts. In the embodiment variant of figures 3A and 3B, (in figure 3B) the slidable coupling 28A is also visible, e.g. of splined type, between the two parts of the Cardan shaft 28 which allows the folder 15 to oscillate.

The device 1 for folding web material also comprises two position sensors of optical type, each position sensor being arranged on a respective side of the folder 15. The position sensors are mounted on supports 35 which project from the arm 30. The two position sensors are positioned in proximity to the second guide, i.e. the second conveyor belts 13.

A first position sensor 36 of said two position sensors is situated between the wall 27 and the curved bar 18. A second position sensor 37 of said two position sensors is situated on an opposite side of the curved bar 18.

Each of the two position sensors 36, 37 is mounted on a respective support 35 so as to allow an adjustment of the position of the respective sensor 36, 37.

Each of the abovementioned sensors 36, 37 comprises an emitter and an optical receiver mutually facing and spaced from each other such that one of the opposite longitudinal edges 17 can slide between the emitter and the receiver.

The two position sensors 36, 37 are configured to detect a relative position of the two opposite longitudinal edges 17 of the layered composite web 6, in particular a height of said two opposite longitudinal edges 17. For example, the two position sensors 36, 37 are configured to provide a different signal as a function of the different of height position of the two opposite longitudinal edges 17.

In other embodiments, not illustrated, the sensors can be different, e.g. cameras or ultrasound sensors or still other sensors.

An electronic control unit, not illustrated, is operatively connected to the motor 26 of the motorized conveyor, to the motor (not illustrated) that moves the first roller 12 and to the motor (not illustrated) that moves the pair of conveyor belts 13. The electronic control unit is also operatively connected to the actuator 31 and to the first and second position sensors 36, 37.

Such electronic control unit is for example the electronic control unit of the entire plant 1.

In use and in accordance with the present invention (figure 7), the layered composite web 6, which lies open in the feeding plane when it is situated just downstream of the first roller 12, encounters the first end 20 of the elongated edge 19. Said elongated edge 19 comes into contact with the center line section 16 of the layered composite web 6 and, while the web 6 advances towards the second guide, it moves the center line section 16 downward while the opposite longitudinal edges 17 continue the rectilinear movement thereof. The center line section 16 is progressively moved away from the feeding plane while the opposite longitudinal edges 17 are maintained at a higher height than the center line section 16 and are progressively moved close to each other. In this manner, the layered composite web 6 is progressively folded in half. In particular, the center line section 16 comes into contact with the upper branch 25 of the conveyor belt 23 and is accompanied or dragged by the upper branch 25 towards the second guide. In other words, the center line section 16 is moved together with the upper branch 25 by sliding on the elongated edge 19.

By manually or automatically adjusting (e.g. by means of the electronic control unit) a power supplied by the motor 26 and hence a speed of the conveyor belt 23, i.e. a dragging speed of the center line section 16, it is possible to prevent the center line section 16 from remaining behind with respect to the opposite longitudinal edges 17 of the layered composite web 6 and hence prevent said layered composite web 6 from being deformed. Since the center line section 16 corresponds with the crotch 200 of the pull-up diapers 2 and the opposite longitudinal edges 7 correspond with the waist 300 of the pull-up diapers 2, the adjustment of the speed of the conveyor belt 23 allows maintaining an alignment between the waist 300 and the crotch 200 of each pull-up diaper 2 and preventing the deformation of the single diapers 2 before welding the sides.

According to one embodiment, it is sufficient to set the speed of the motorized conveyor at the start of a production batch and as a function of a speed of the plant 1 , and in particular of a speed of the first roller 12 and a speed of the second conveyor belts 13 and/or of characteristics/sizes of the pull-up diapers 2 to be produced, so that the abovementioned alignment is maintained.

The electronic control unit receives, from each of said first and second position sensors 36, 37, a respective signal that is a function of a position of a segment of the respective opposite longitudinal edge 17 of the layered composite web 6 when this is situated just before the second conveyor belts 13. In such position, the step of folding is nearly complete, the layered composite web 6 is arranged as a V and the two abovementioned opposite longitudinal edges 17 are close to each other even if they do not touch (figures 5 and 6).

The electronic control unit calculates a difference between the two signals. Such difference is a function of a difference in height “Ah” (non-alignment) of the two opposite longitudinal edges 17 (figure 5). If such difference is different from zero, this means that the center line section 16 of the layered composite web 6 is moved laterally with respect to the elongated edge 19, as in figure 5.

If said difference is different from zero, the electronic control unit is programmed for controlling the actuator 31 so as to rotate the folder 15 around the adjustment axis “X-X” by an angle “a” and in a direction such to bring the two opposite longitudinal edges 17 to a same height and therefore cancel the abovementioned height difference “Ah”. The electronic control unit is programmed for rotating the folder 15 towards the longitudinal edge 17 placed higher and by an angle proportional to the detected height difference “Ah”.

For example, with reference to figures 4, 5 and 6, if the longitudinal edge 17 placed at the first position sensor 36 is placed higher than the longitudinal edge 17 placed at the second position sensor 37 (as in figure 5), the folder 15 is rotated towards the wall 27 in order to move the first end 20 of the elongated edge 19 towards said wall 27 and in this manner raise the longitudinal edge 17 placed at the second position sensor 37 and lower the other, up to aligning the two edges with each other (figure 6).

The opposite longitudinal edges 17 of the layered composite web 6 are therefore aligned with each other when they enter between the second conveyor belts 13 and, in this manner, the zones belonging to the two opposite longitudinal edges 17, and to be welded together, precisely mate.

Downstream of the second conveyor belts 13, the welding stations provide for executing the welds correctly.

In other embodiments that are not illustrated in detail, the folder is manually moved around the adjustment axis, by actuating, by means of a lever, the actuator which for example is of screw/nut screw type, and then locked in the desired position by means of suitable locking devices. In such case, the position of the opposite longitudinal edges of the web material is visually checked by an operator or it can be provided on a display by the control unit connected to the abovementioned sensors.

Elements 1 Manufacturing plant for producing layered composite articles

2 Layered composite article / pull-up diapers

3 Material web

4 Reel

5 First sector 6 Layered composite web

7 Second sector

8 Third sector

9 Fourth sector

10 Reel holder 11 Device for folding web material

12 First roller

13 Pair of conveyor belts

14 Second rollers

15 Folder 16 Center line section

17 Opposite longitudinal edges

18 Curved bar

19 Elongated edge

20 First end of the elongated edge 21 Second end of the elongated edge

22 Motorized conveyor

23 Conveyor belt

24 Pulleys

25 Upper branch of the conveyor belt 26 Motor

27 Fixed frame

28 Cardan shaft

28A Slidable coupling

29 Support 30 Arm

31 Actuator

32 Rod

33 Rod end 34 Opposite rod end

35 Supports

36 First position sensor

37 Second position sensor 100 Cutting lines 200 Crotch 300 Waist F Transport direction V Feed direction x-x First roller rotation axis Y-Y Second roller rotation axis

Claims

1. Device for folding web material in a plant for producing layered composite articles, preferably pull-up diapers, comprising: a first guide defining a feeding plane for feeding a web material (6); a second guide defining a receiving plane for receiving the web material (6), wherein the second guide is positioned downstream of the first guide with respect to a feed direction (V) of said web material (6), wherein the receiving plane is substantially orthogonal to the feeding plane; a folder (15) arranged between the first guide and the second guide and comprising an elongated edge (19) extending between the first guide and the second guide along said feed direction (V); wherein the elongated edge (19) extends from the first guide towards the second guide in the receiving plane and away from the feeding plane, to progressively move away an intermediate section (16) of the web material (6) from the feeding plane and folding said web material (6) in two while it travels from the first guide towards the second guide; a motorized conveyor (22) arranged along the elongated edge (19), having a movable surface facing the elongated edge (19), movable from the first guide towards the second guide and configured to accompany and/or drag along said elongated edge (19) the intermediate section (16) of the web material (6) lying between the elongated edge (19) and the movable surface.

2. Device according to claim 1 , wherein the motorized conveyor (22) lies below the folder (15).

3. Device according to claim 1 or 2, wherein the motorized conveyor (22) comprises a conveyor belt (23) extending at least in part along the elongated edge (19); wherein the movable surface is an upper branch of the conveyor belt (23).

4. Device according to claim 3, wherein the conveyor belt (23) extends along a closed path lying substantially in the receiving plane.

5. Device according to claim 3 or 4, wherein the motorized conveyor (22) comprises a plurality of pulleys (24), the conveyor belt (23) being wound on said pulleys (24).

6. Device according to claim 5, wherein at least one of said pulleys (24) is motorized.

7. Device according to claim 5 or 6, wherein a motor is connected to at least one of the pulleys (24), in order to rotate said at least one pulley (24) and move the conveyor belt (23).

8. Device according to claim 5 or 6 or 7, wherein the conveyor belt (23) is toothed and teeth of the conveyor belt (23) are engaged with the pulleys (24).

9. Device according to one of claims 3 to 8, wherein the conveyor belt (23) is a flat belt, polycord, trapezoidal belt.

10. Device according to one of claims 1 to 9, wherein the folder (15) comprises a curved bar (18) extending mainly in the receiving plane; wherein the elongated edge (19) is a lower edge of said curved bar (18).

11. Device according to one of claims 1 to 10, wherein the folder (15) can be oriented around an adjustment axis (K-K) arranged in proximity to the second guide and lying in the receiving plane, to change a position of a first end (20) of said elongated edge (19) with respect to the first guide so as to adjust a mutual position of opposite longitudinal edges (17) of the web material (6) at the second guide.

12. Device according to claim 11 , wherein the folder (15) can be oriented around the adjustment axis (K-K) by an angle (a) comprised between +/- 10 ° with respect to an average position corresponding to a middle point of the first guide.

13. Device according to claim 11 or 12, wherein the motorized conveyor (22) can be oriented around the adjustment axis (K-K).

14. Device according to claim 13, wherein the motorized conveyor (22) is rigidly connected to the folder (15) to move together with said folder (15) around the adjustment axis (K-K).

15. Device according to claim 11 or 12, wherein the motorized conveyor (22) is fixed and the movable surface has a width such that said movable surface always faces the elongated edge (19) for every position of the folder (15) around the adjustment axis (K-K).