Patent Publication Number: US-2021171310-A1

Title: Folding apparatus for a continuous web

Description:
TECHNICAL FIELD 
     This description relates to a folder or folding apparatus for a continuous web and in particular an apparatus for folding in two a continuous composite web intended for making products of the absorbent hygiene article type, for example nappies or incontinence pants. 
     BACKGROUND ART 
     During the production of nappies or incontinence pants, for example those wearable like pants, a semi-finished product, in the form of a composite web, usually comprising multiple components which have been assembled, is folded in two according to a longitudinal folding line. 
     In that case, what is always wanted is for the longitudinal edges of the web, which following folding are superposed, to be in a precise position relative to each other, for example aligned. 
     In this context, the technical purpose which forms the basis of this description is to propose a folding apparatus for a composite web which allows the longitudinal edges of a web, once the web has been folded in two, to be positioned in a predetermined position relative to each other, for example aligned. 
     DISCLOSURE OF THE INVENTION 
     The aim of this description is to propose a folding apparatus for a web which is being fed along a plant for the production or manufacture of absorbent hygiene articles, which is reliable for positioning the longitudinal edges of the web relative to each other, once the web has been folded. 
     The technical purpose indicated and at least the aim specified are substantially achieved by a folding apparatus according to one or more of the appended claims. 
     According to one aspect of the description, the description relates to a folding apparatus for a continuous web being fed in a plant for manufacturing absorbent hygiene articles. 
     The continuous web is preferably folded in a transversal direction according to a longitudinal folding line parallel to a web feeding line. 
     According to one aspect of the description the apparatus is also preferably equipped for positioning the longitudinal edges of the web in a predetermined position relative to each other, once the web has been folded. 
     According to one aspect of the description, the folding apparatus comprises a folding section where the web is folded in two according to a longitudinal folding line. 
     According to one aspect of the description, the web is folded, for example, in such a way that the opposite longitudinal edges of the self-same web are superposed at the end of folding. 
     The folding apparatus according to this description comprises a folding section where folding of the web effectively takes place. 
     Folding can occur, in use, because the web passes in the folding section. 
     According to one aspect of the description, the folding apparatus comprises a feeding system for the continuous web, preferably folded, located downstream of the folding section according to the web feeding direction. 
     The folding line is defined by a contact unit for the web which is part of the folding section. 
     According to one aspect of the description, the folding section comprises a first guide and a second guide which are located on opposite sides of the contact unit and respectively having a first sliding surface for the continuous web and a second sliding surface for the continuous web. 
     The first sliding surface of the first guide and the second sliding surface of the second guide extend in a helical fashion and are preferably specular relative to a lying plane of the folding line. 
     The web being fed along the guides passes from a spread out, open configuration, to a transversally folded configuration, with two longitudinal flaps side by side and separated by the folding line. 
     Folding of the web is preferably guided by the guides from start to finish, therefore it is extremely precise. 
     According to one aspect of the description, the sliding surfaces have a substantially flat and horizontal infeed section and a substantially flat and vertical outfeed section. 
     The sliding surfaces converge from the infeed section towards the outfeed section in such a way that the web fed preferably folded downstream, reaches the folded configuration along the guides. 
     According to one aspect of the description, the position of the guides is adjustable around an axis of rotation which is transversal, for example perpendicular, to the feeding line, for controlling the relative position of the longitudinal edges of the web once it has been folded. 
     The position of the guides relative to the axis of rotation is preferably controlled using feedback by means of a position sensor which checks the relative positioning of the edges of the web and sends a corresponding control signal to a computerised control unit which by means of a respective actuator adjusts the position of the guides about the axis of rotation. 
     According to one aspect of the description, it may be possible to adjust the position of only one of the guides or of both of the guides depending on the position of the edges. 
     According to one aspect of the description, the feeding system may comprise motor-driven belts which contribute to feeding the flaps of the web on the corresponding guides. 
     Preferably, the motor-driven belts are as one with the corresponding guide in the oscillation or in the positioning about the axis of rotation. 
     According to one aspect of the description, the contact unit comprises a motor-driven belt comprising a branch movable in the web feeding direction and defining the contact for the web and the folding line. 
     The belt of the contact unit contributes to feeding the web in the folding section. 
     According to one aspect of the description, the contact unit may oscillate about an axis of rotation which is transversal, preferably orthogonal, to the web feeding line. 
     The position of the contact unit relative to its own axis of rotation affects web tension which can be set to a predetermined value. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further features and advantages of the folding apparatus according to this description are more apparent in the non-limiting description of an embodiment of it, illustrated in the accompanying drawings, in which: 
         FIG. 1  is a schematic side view partly in bocks and with some parts cut away for greater clarity of a folding apparatus according to this description; 
         FIG. 2  is a schematic perspective view with some parts cut away for greater clarity of a folding section of the apparatus of  FIG. 1 ; 
         FIG. 3  is a bottom plan view of a detail of the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     With reference to the accompanying drawings, in particular to  FIG. 1 , the numeral  1  denotes a folding apparatus for a continuous web  100  being fed in a plant  200  for the production of absorbent hygiene articles which is only partly illustrated. 
     The web  100  is intended to be folded in two along a longitudinal folding line L parallel to a feeding line D of the continuous web. 
     The web  100  is for example a composite web comprising a pair of lateral strips which extend along the longitudinal line of the self-same web  100  and are interconnected, for example, by absorbent pads extending along the transversal line of the web and intended to form absorbent articles of the type called “pants”; for simplicity, in the accompanying figures the web  100  is only shown in a very simple form. 
     Preferably, the web  100  is folded in the folding apparatus  1  in such a way that its longitudinal edges  100   a ,  100   b  are placed in a predetermined position relative to each other, for example substantially superposed. 
     It should be noticed that, for greater clarity, in the examples illustrated the folded web  100  is shown with the edges  100   a ,  100   b  slightly away from each other at the end of folding, however, the edges  100   a ,  100   b  may be substantially superposed even based on the thicknesses of the web  100 . 
     The apparatus  1  comprises a folding section  2  and, preferably, a feeding system  3  for feeding the folded continuous web  100  which is, at least partly, located downstream of the folding section  2  according to a web feeding direction V. 
     The system  3  comprises, for example, opposing rollers, not illustrated, which are substantially known and feed or contribute to feeding of the web  100  along the production plant. 
     The system  3  is not necessarily part of the apparatus  1  and may be located in any part along the plant and is used, for folding purposes, to make the web pass in the section  2 . 
     In the embodiment illustrated, the folding section  2  comprises a contact unit  4  for the web  100 . 
     The unit  4  extends mainly according to the feeding line D of the continuous web  100  and defines the folding line L. 
     The unit  4  has a first end  4   a  and a second end  4   b  which is located downstream of the first end  4   a  according to the feeding direction V of the web  100 . 
     During its movement along the line D in the direction V, the web  100  is folded in a transversal direction, preferably into a “U” or “V” shape, around the unit  4 , that is to say, according to the folding line L. 
     In the example illustrated, the web  100  has two flaps or portions  101 ,  102  which are respectively delimited by the folding line L and the first edge  100   a  and by the folding line L and the second edge  100   b.    
     In particular, the flaps  101 ,  102  are easily identifiable considering the folded web where they are at an angle to each other and meet at the folding line, for example as illustrated in  FIG. 2 . 
     The folding section  2  comprises a first and a second guide  5 ,  6  for the continuous web which are located on opposite sides of the contact unit  4 . 
     The guides  5 ,  6  extend mainly according to the line D and, preferably together with the unit  4 , cause the folding of the web  100  during feeding. 
     The guide  5  has a sliding surface  5   a  for the web  100  and the guides  6  has a sliding surface  6   a  for the web  100 . 
     In the example illustrated, the flap  101  at least partly slides in contact with the surface  5   a  whilst the flap  102  at least partly slides in contact with the surface  6   a  along the section  2 . 
     The flap  101  and the flap  102  remain substantially separated by the contact unit  4  as they pass through the section  2 . 
     Preferably, the layout of the folding section  2  ensures that the guides  5  and  6  are above the web  100  when it is not folded or between the two flaps  101 ,  102  of the web when it is folded. 
     In alternative embodiments not illustrated, the folding section  2  is substantially inverted, observing  FIG. 1  for example, and the web  100  is fed on top of the guides  5 ,  6 . 
     The sliding surface  5   a  of the first guide  5  extends in a helical fashion and has an infeed section  51  and an outfeed section  52  which is downstream of the infeed section according to the feeding direction V of the web  100 . 
     As illustrated, the infeed section  51  of the surface  5   a  lies in a first plane P 1 . 
     The plane P 1  is preferably parallel to a lying plane P of the web  100  upstream of the folding section  2  according to the feeding direction of the web  100 . 
     The outfeed section  52  of the surface  5   a  lies in a second plane P 2  which is transversal to the plane P 1  in such a way as to form the “U” or “V” shaped fold in the web  100 . 
     In particular, the surface  5   a  shaped in this way causes a substantially 90° rotation of the flap  101  about the folding line L. 
     Preferably the plane P 2  is substantially orthogonal to the plane P 1 . 
     The sliding surface  6   a  of the second guide  6  extends in a helical fashion and has an infeed section  61  and an outfeed section  62  which is downstream of the infeed section according to the feeding direction V of the web  100 . 
     As illustrated, the infeed section  61  of the surface  6   a  lies in a third plane P 3 . 
     The plane P 3  is preferably parallel to the lying plane P of the web  100  upstream of the folding section  2  according to the feeding direction of the web  100 . 
     The outfeed section  62  of the surface  6   a  lies in a fourth plane P 4  which is transversal to the plane P 3  in such a way as to form the “U” or “V” shaped fold in the web  100 . 
     In particular, the surface  5   a  shaped in this way causes a substantially 90° rotation of the flap  102  about the folding line L. 
     Preferably the plane P 4  is substantially orthogonal to the plane P 3 . 
     Advantageously, the web  100  is not in a folded configuration upon entering the sections  51  and  61  and it has been folded when it exits the sections  52 ,  62 . 
     In the preferred embodiment illustrated, the planes P 1  and P 3  coincide with each other and the planes P 2 , P 4  are substantially orthogonal to the plane P and converge in the feeding direction V of the web  100 . 
     The surfaces  5   a ,  6   a  converge at the respective outfeed sections  52 ,  62  in such a way that downstream of the section  2  the web  100  is folded. 
     In a preferred embodiment, the surfaces  5   a ,  6   a  are specular relative to a lying plane PL of the folding line which is preferably perpendicular to the plane P and parallel to the planes P 2 , P 4 . 
     With reference to  FIG. 1 , the plane PL corresponds to the plane of  FIG. 1  itself. 
     In order to adjust the relative position of the edges  100   a ,  100   b  of the web  100  once the web is folded, the apparatus  1  comprises a related adjusting system  7 . 
     The guide  5  and the guide  6  pivot at a frame  201  of the above-mentioned production plant and are rotatable about an axis of rotation R which is transversal, in particular orthogonal, to the feeding line D of the web  100 . 
     The adjusting system  7  comprises a first and a second actuator  8 ,  9  which are connected respectively to the guide  5  and to the guide  6  for changing their position about the axis R. 
     The adjusting system  7  comprises at least one position sensor, schematically illustrated with a block  10  in  FIG. 1 , for checking the relative position of the edges  100   a ,  100   b  downstream of the folding section  2 , for example in a vertical plane according to an axis Y. 
     For simplicity reference is made to the case in which the edges  100   a ,  100   b  must be substantially superposed, meaning any desired and predetermined relative position to be reached following the folding. 
     For example, the sensor  10  is of the optical type and, for example, of the fork type. 
     The adjusting system  7  comprises a computerised control unit, schematically illustrated with a block  11 , in communication with the sensor  10  and with the actuators  8 ,  9 . 
     The unit  11  is configured for moving, by means of the actuators  8 ,  9 , the guides  5 ,  6  about the axis R depending on a piece of information I about the relative position of the edges  100   a ,  100   b  as received from the sensor  10 . 
     In alternative embodiments not illustrated, in order to adjust the position of the edges  100   a ,  100   b  only one of the guides  5 ,  6  is movable about the axis R of rotation, controlled by the corresponding actuator which is controlled by the unit  11 . 
     In the embodiment illustrated, the feeding system  3  for the web comprises motor-driven belts, for example of the type looped around at least two rollers one of which is motor-driven, the belts being located at the guides  5 ,  6  for promoting feeding of the web  100  at the guides. 
     In the example illustrated, the feeding system  3 , substantially at the folding section  2 , comprises a first motor-driven belt  12  alongside the sliding surface  5   a  of the first guide  5 . 
     The belt  12  comprises a branch  12   a  movable in the feeding direction of the continuous web  100  and facing the surface  5   a.    
     Together with the surface  5   a  the branch  12   a  delimits a passage  13  for the continuous web in which the flap  101  passes, if necessary fed by the belt  12  by means of the branch  12   a.    
     In  FIG. 3  for clarity a space is visible between the branch  12   a  and the flap  101 ; preferably, when the contribution of the belt  12  is necessary for feeding the web in the section  2 , the branch  12   a  is, in use, in contact with the web  100 . 
     Substantially at the folding section  2 , the feeding system  3  comprises a second motor-driven belt  14  alongside the sliding surface  6   a  of the second guide  6 . 
     The belt  14  comprises a branch  14   a  movable in the feeding direction of the continuous web  100  and facing the surface  6   a.    
     Together with the  6   a  the branch  14   a  delimits a passage  15  for the continuous web in which the flap  102  passes, if necessary fed by the belt  14  by means of the branch  14   a.    
     In  FIG. 3  for clarity a space is visible between the branch  14   a  and the flap  102 ; preferably, when the contribution of the belt  14  is necessary for feeding the web in the section  2 , the branch  14   a  is, in use, in contact with the web  100 . 
     In a preferred embodiment, the belt  12  is located substantially at the outfeed section  52  of the surface  5   a  in such a way that the branch  12   a  accompanies web  100 , in particular the flap  101 , at the outfeed of the section  2 . 
     In a preferred embodiment, the belt  14  is located substantially at the outfeed section  62  of the surface  6   a  in such a way that the branch  14   a  accompanies the web  100 , in particular the flap  102 , at the outfeed of the section  2 . 
     In a preferred embodiment, the belts  12 ,  14  are as one respectively with the guide  5  and with the guide  6  in the motion about the axis R of rotation. 
     For example, the apparatus  1  comprises a single supporting structure which supports the guide  5  and the belt  12  and is rotatable about the axis R and a single supporting structure which supports the guide  6  and the belt  14  and is rotatable about the axis R. 
     In this case, the actuators  8 ,  9  are fastened and operational respectively on the first supporting structure and on the second supporting structure. 
     In a preferred embodiment, the above-mentioned contact unit  4  comprises a corresponding motor-driven belt  16  which operates in conjunction with the web feeding system  3  or is part of it. 
     The belt  16  is of the substantially known type, looped around at least two rollers one of which is motor-driven. 
     The belt  16  comprises a branch  16   a  movable in the feeding direction V of the web  100  located at the folding line L which is at least partly defined by the self-same branch  16   a ; in use the web  100  is folded into a “V” or “U” shape around the branch  16   a.    
     By means of the branch  16   a  the belt  16  promotes feeding of the web  100  in the folding section  2 . 
     In the example illustrated, the branch  16   a  is preferably guided by a train of rollers  160  which preferably extends along the whole section  2 . 
     The contact unit  4 , and if necessary the branch  16   a  if the belt  16  is provided, preferably extends from the infeed sections  51 ,  61  of the guides  5 ,  6  at least as far as the outfeed sections  52  and  62  of the guides. 
     In the example illustrated, the unit  4  extends beyond the outfeed sections  52  and  62  in the feeding direction V of the web  100 , that is to say, the end  4   b  is located downstream of the sections  52 ,  62  according to the feeding direction V. 
     In order to facilitate sliding of the web  100  once it has been folded, the unit  4  preferably comprises a guard  17  at least in the portion which extends beyond the guides  5 ,  6  in the direction V. 
     In a preferred embodiment, the unit  4  pivots at the frame  200  of the plant and is movable about an axis R 4  of rotation. 
     In the example illustrated, the axis R 4  coincides with the axis R of rotation of the guides  5 ,  6 . 
     The section  2  comprises an actuator  18  operatively acting on the unit  4  for adjusting its position about the axis R 4 . 
     That adjustment allows the tension of the web  100  to be set during folding, allowing improved control of it. The position of the unit  4  is for example determined by the type of material of the web  100  or by the composition of it. 
     In the example illustrated, the unit  4  pivots at the frame  100  substantially at its first end  4   a.    
     In one embodiment, the apparatus  1  comprises, downstream of the folding section  2  according to the feeding direction V of the web  100 , a station  19  for stabilising the fold made in the web. 
     In the example illustrated, the station  19  comprises a first and second looped belt  20 ,  21 , which are motor-driven and located on opposite sides of the web  100  feeding path. 
     The belt  20  comprises a branch  20   a  movable in the direction V parallel to the web  100  and the belt  21  comprises a branch  21   a  movable in the direction V parallel to the web  100 . 
     The branches  20   a  and  21   a  delimit a channel  22  for passage of the folded web  100  and contribute to feeding the self-same web  100 . 
     In that sense, the belts  20 ,  21  may be considered part of the feeding system  3 . 
     The relative position of the branches  20   a  and  21   a  is also set in such a way as to stabilise the fold made in the section  2  upstream of the station  19 , that is to say, to stabilise the folded web  100 , for example by compressing it, and prepare it for subsequent processing in the production plant.