Abstract:
A device for butt-joining a product made of strips or webs of material includes a soldering and cutting workstation and a rolling workstation. The butt-joining device includes apparatus for adjusting the relative position of a rolling component and the soldering and cutting zone to be rolled.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a device for butt-joining a product in a strip or web of material. Such a device is used to join end-to-end two successive strips or webs of product: the initial end of a second strip or web of product is secured to the final end of a first strip or web of product that has been used in its virtual totality. Said first and second strips or webs of product are usually wound on unwinding reels. 
         [0002]    As known in document U.S. Pat. No. 3,384,527 A, a device for butt-joining a product in form of a web or strip of material comprises:
       a heat-welding and cutting workstation capable of welding and cutting by heating by means of electrical resistances two thicknesses of product in a heat-welding and cutting zone,   a laminating workstation with laminating means by heating by means of electrical resistances of the heat-welding and cutting zone,
 
between which said product in a strip or web of material is designed to be moved in a movement defined by means for retaining the product upstream of the laminating workstation and by means for pulling the product downstream of the laminating workstation.
       
 
         [0005]    Such a device is usually used for the butt-joining of products that can be heat welded by ultrasound, such as nonwovens, plastic films or else fabrics comprising hot-melt material. 
         [0006]    In this known butt-joining device, after execution of the heat-welding and cutting operations, the product is moved manually by an operator to the laminating workstation in order to place the heat-welding and cutting zone to be laminated in correspondence with the laminating means. 
         [0007]    The manual positional adjustment operations necessary that are carried out by an operator involve relatively long stopping times of the machine processing the product in a strip or web of material, inducing a considerable loss of productivity. Specifically, it is sometimes possible that the butt-joining operation takes more time than the unwinding and complete treatment of a reel of product. 
         [0008]    The manual intervention of the operator must also be carried out by inserting his hands and arms into the butt-joining device and into the machine that treats the product comprising said butt-joining device, which involves risks for the safety of the operator. 
         [0009]    Although the manual intervention of a skilled operator makes it possible to ascertain certain parameters such as the stretching of the product by elastic deformation when it is unwound, the manual operation of positioning the heat-welding and cutting zone in correspondence with the laminating means nevertheless remains approximate, notably for products in a strip or web of material of very great width for which an operator has difficulty in placing the rectilinear heat-welding and cutting zone with an appropriate parallelism with respect to the equally rectilinear path of the laminating means. 
         [0010]    If it is sought to move the product in a strip by mechanical retention and pulling means, the position of the heat-welding and cutting zone then depends on the stretching of the product under the effect of it being pulled, and an offset may therefore occur relative to the laminating workstation if the mechanical characteristics of the product vary. 
         [0011]    The result of this is that the heat-welding and cutting zone to be laminated is often placed in an unsatisfactory manner with respect to the laminating means, which may cause the inappropriate laminating of portions of the product with a single thickness which will thus be weakened, and which may, on the other hand, cause the absence of laminating of portions of the heat-welding and cutting zone to be laminated which then, following the heat-welding and cutting operations, has a fragile and precarious cohesion. These imperfections may induce a partial or complete tearing of the product when the latter is moved in tension to a subsequent workstation. 
       SUMMARY OF THE INVENTION 
       [0012]    The problem proposed by the invention is to make possible and effective a mechanization of the operations for butt-joining a product in a strip or a web of material, by reducing the influence of the variations of the mechanical characteristics of the product such as its elasticity, so as to limit the manual interventions of an operator and the dexterity required of the latter, and so far as to improve productivity and the safety of the operators. 
         [0013]    In order to achieve these and other objectives, the invention proposes a device for butt-joining a product in a strip or in a web of material, comprising:
       a heat-welding and cutting workstation capable of heat-welding and cutting two thicknesses of product along a heat-welding and cutting zone,   a laminating workstation with means for laminating by heating the heat-welding and cutting zone,
 
between which said product in a strip or in a web of material is designed to be moved according to a movement defined by means for retaining the product upstream of the laminating workstation and by a means for pulling the product downstream of the laminating workstation;
 
according to the invention, in the heat-welding and cutting workstation and in the laminating workstation, the heating is carried out by ultrasound, and the butt-joining device comprises means for adjusting the relative position of the laminating means and of the heat-welding and cutting zone to be laminated, so that, after heat-welding and cutting and after movement of the heat-welding and cutting zone to the laminating workstation, the heat-welding and cutting zone to be laminated is placed in correspondence with the laminating means.
       
 
         [0016]    The adjustment means allow an effective adjustment of the relative position of the laminating means and of the heat-welding and cutting zone to be laminated during the laminating operation when the movement of the product is ensured by mechanical retention and pulling means, such that said relative position is independent of the mechanical characteristics of the product such as its elasticity which vary from one product to another depending on, for example, the thickness and the nature of the materials of which it is made. 
         [0017]    Ultrasound heating concentrates the heating only in the material of the product in a strip or web, and only in the zone to be heat-welded, to be cut or to be laminated. The result of this is a greater accuracy of the work and better reproducibility. 
         [0018]    Moreover, in the case of mechanical means for retaining and pulling the product, the conditions of moving the product are usually constant for a series of successive reels of one and the same product. 
         [0019]    It is then possible to carry out a first adjustment of the relative position of the laminating means relative to the heat-welding and cutting zone to be laminated during the butt-joining between the first two reels. The adjustment, after having been carried out, can be retained for all the subsequent butt-joining operations intended to be carried out on the same product in a strip or web of material, with an appropriate and reproducible quality. 
         [0020]    The manual intervention of an operator is therefore necessary only for a first adjustment, no manual operation for adjusting the relative position of the laminating means and of the heat-welding and cutting zone to be laminated thereafter being necessary. 
         [0021]    According to a first embodiment of the invention, it can be provided that:
       the adjustment means comprise means for the relative movement of the laminating workstation and heat-welding and cutting workstation,   the adjustment means comprise locking means suitable for fixing the laminating workstation and the heat-welding and cutting workstation at different distances of relative separation.       
 
         [0024]    Adjusting the relative spacing distance between the heat-welding and cutting workstation and the laminating workstation makes it possible to make the following lengths equal: on the one hand the length of the path traveled by the product between the retention means and the heat-welding and cutting workstation before the advance by pulling, and on the other hand the length of the path traveled by the product between the retention means and the laminating workstation after the advance by pulling. 
         [0025]    According to a second embodiment of the invention, it can be provided, as an alternative or in addition to the first embodiment of the invention, that:
       the adjustment means comprise a first product deflection bar, situated between the retention means and the heat-welding and cutting workstation and extending in a first direction of extension perpendicular to the direction of travel of the product,   the adjustment means comprise first means for transverse movement of the first deflection bar, capable of moving the first deflection bar so as to adjust the length of the upstream section of product extending from the retention means to the heat-welding and cutting workstation.       
 
         [0028]    By moving the first product deflection bar, the length of the upstream section of product extending from the retention means to the heat-welding and cutting workstation is lengthened or shortened so that this length exactly matches the length of product that will extend from the retention means to the laminating workstation once the heat-welding and cutting zone has been moved to said laminating workstation. 
         [0029]    Advantageously, the device may comprise means for retaining the product upstream of the heat-welding and cutting workstation, which means are capable of immobilizing an upstream section of product extending from the retention means to the heat-welding and cutting workstation. 
         [0030]    The retention means may preferably comprise:
       a third product deflection bar,   pinching means that can be moved selectively between a retention position in which the pinching means press on the third product deflection bar by means of the product, and a position of release in which the pinching means are separated from the third deflection bar.       
 
         [0033]    Such pinching means are simple to produce and easy to automate for a reliable and effective immobilization of the product. Preferably, the pinching means are placed as close as possible to the heat-welding and cutting workstation, which means that the third product deflection bar is preferably the deflection bar placed immediately in front of the heat-welding and cutting station on the path of the product. Such an arrangement makes it possible to limit the length of the upstream section of product extending from the retention means to the heat-welding and cutting workstation, which reduces the risks of drift by elastic lengthening of this upstream section. 
         [0034]    As an alternative to the use of pinching means, it is conceivable to use any appropriate means for immobilizing the unwinding of the product in a strip or web of material, by immobilizing for example the unwinding reel on which the said product in a strip or web of material is usually wound. 
         [0035]    Advantageously, it can be provided that:
       the laminating workstation comprises a laminating counterpart extending in a third direction of extension, with a work face that is substantially flat,   the laminating means are secured to a support that can be moved in the third direction of extension opposite the laminating counterpart,   the laminating means are secured to bearing means formed to press against the work face of the laminating counterpart,   the laminating means are secured to the support by means of connecting means formed to allow:
           a movement of translation in a direction substantially perpendicular to the plane of the work face,   a rotary movement about a direction substantially parallel to the third direction of extension.   
               
 
         [0042]    Such connecting and bearing means make it possible to flatten the product against the whole surface area of the work face of the laminating counterpart, which allows the laminating means to follow the possible deformations (twists, bends, etc.) of the laminating counterpart so that an even and smooth laminating is carried out over the whole width of the product in a strip and over the whole length of the heat-welding and cutting zone to be laminated. 
         [0043]    Preferably, the bearing means may, by means of the product, press against the work face of the laminating counterpart on either side of the heat-welding and cutting zone to be laminated. 
         [0044]    The bearing means therefore press on the product on either side of the heat-welding and cutting zone to be laminated and do not touch the heat-welding and cutting zone to be laminated which has, before laminating, an ungainly geometry and a precarious fragile cohesion. Coming into direct contact on the heat-welding and cutting zone to be laminated which has been geometrically deformed by being flattened could cause an at least partially breakage of the heat-welding and cutting zone to be laminated. 
         [0045]    Advantageously, the bearing means may comprise rolling means with two wheels situated on either side of the laminating means. The rolling means make it possible to flatten the product onto the laminating counterpart while limiting the risks of jamming the product under the bearing means. 
         [0046]    According to a first variant, the heat-welding and cutting zone of the product may be moved by pulling from the heat-welding and cutting workstation to the laminating workstation by means for advancing the product of a subsequent workstation situated downstream of the laminating workstation. 
         [0047]    In this way advancement means are used that are already present in the machine containing the butt-joining device or in the next machine with a subsequent workstation. This variant is economical because it uses existing actuators. The subsequent workstation may, for example, be a station for cutting the product along its width into a plurality of strips of reduced width with winding means for producing reels of reduced width. 
         [0048]    According to a second variant, it can be provided that:
       the device comprises accumulation means that the product downstream of the laminating workstation traverses,   the accumulation means are suitable for moving by pulling the heat-welding and cutting zone to be laminated of the product from the heat-welding and cutting workstation to the laminating workstation.       
 
         [0051]    Using accumulation means makes it easier to automate the advance of the product because one then dispenses with the usually high inertia of the existing actuators used for a subsequent workstation situated downstream of the laminating workstation. 
         [0052]    Moreover, one avoids making said subsequent workstation work at a usually low movement speed which does not correspond to the nominal working speed of this subsequent workstation and which would induce zones of defect on the treated product. 
         [0053]    According to a first possibility, the product may traverse the accumulation means on a zigzag path of which the length is adjustable. 
         [0054]    According to another possibility, the accumulation means may comprise:
       at least one second product deflection bar situated downstream of the laminating workstation and extending in a second direction of extension perpendicular to the direction of travel of the product,   second transverse movement means of the second deflection bar so as to adjust the length of the product section situated downstream of the laminating workstation.       
 
         [0057]    Advantageously, the movement means can move the first deflection bar or the second deflection bar in a movement of translation. 
         [0058]    As an alternative, the movement means can move the first deflection bar or the second deflection bar in a rotary movement about an offset axis parallel to the direction of extension of said first deflection bar or second deflection bar. 
         [0059]    A rotary movement by pivoting of the first or the second deflection bar about an offset axis parallel to its direction of extension is easier to achieve than a movement by translation in the case of treating a product of great width requiring a machine of great width. Specifically, moving a bar of great length (occupying the whole width of the product) sideways in translation may present risks of immobilization and of losses of parallelism by bending or twisting. 
         [0060]    Advantageously, the heat-welding and cutting workstation may comprise heat-welding-cutting means. This improves the compactness of the butt-joining device and further improves the accuracy in the positioning of the zone to be laminated relative to the laminating means, the position of the heat-welding zone exactly matching the position of the cutting zone. 
         [0061]    Preferably, it can be provided that:
       the heat-welding and cutting workstation comprises a heat-welding and cutting counterpart extending in a fourth direction of extension, with a substantially flat work face,   the heat-welding-cutting means comprise a sonotrode with a sharpened face.       
 
         [0064]    Advantageously, it can be provided that:
       the laminating workstation comprises a laminating counterpart extending in a third direction of extension, with a substantially flat work face,   the laminating means comprise a sonotrode with a substantially flat face.       
 
         [0067]    Advantageously, the butt-joining device may comprise means for deforming the work face of the heat-welding and cutting counterpart and/or of the laminating counterpart. 
         [0068]    It is therefore possible to rectify the geometry of the work surface in cases in which it might have deformations by bending or twisting of the counterpart due to its great length. 
         [0069]    In practice, it can advantageously be provided that:
       the heat-welding and cutting counterpart and/or the laminating counterpart comprises a Tshaped cross section, the work face being supported by the external face of the upper bar of the T,   the deformation means comprise at least one screw designed to press against the vertical bar of the T, preferably two screws each situated in the vicinity of one end of said counterpart.       
 
         [0072]    Preferably, the heat-welding and cutting workstation and/or the laminating workstation may comprise pressing means designed to press against the corresponding counterpart by means of the product. The pressing means allow a reliable positional retention of the product with respect to the heat-welding and cutting means and/or the laminating means during the heat-welding, cutting and/or laminating operations. 
         [0073]    Advantageously, it can be provided that the counterpart(s) can be moved toward the corresponding pressing means in order to cause said pressure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0074]    Other objects, features and advantages of the present invention will emerge from the following description of particular embodiments, made with respect to the appended drawings, amongst which: 
           [0075]      FIG. 1  is a view in perspective of a machine for treating a product in a strip or web of material, comprising a butt-joining device according to the invention; 
           [0076]      FIG. 2  is a partial side view of the butt-joining device of the machine of  FIG. 1 ; 
           [0077]      FIG. 3  is a view in perspective of the heat-welding and cutting workstation and of the laminating workstation of the device of  FIG. 2 , comprising adjustment means according to a first embodiment; 
           [0078]      FIGS. 4 to 9  illustrate schematically the successive steps of operation of a butt-joining device according to the first embodiment of the invention; 
           [0079]      FIG. 10  is a schematic view illustrating the operation of a butt-joining device according to a second embodiment of the invention; 
           [0080]      FIG. 11  is a schematic view of a variant butt-joining device according to the invention comprising a first type of accumulation means; 
           [0081]      FIG. 12  is a schematic view of a variant butt-joining device according to the invention comprising a second type of accumulation means; 
           [0082]      FIG. 13  is a schematic view of a variant butt-joining device according to the invention comprising a third type of accumulation means; 
           [0083]      FIG. 14  is a front view of a laminating station; 
           [0084]      FIG. 15  is a side view of the laminating station of  FIG. 14 ; 
           [0085]      FIG. 16  is a front view of the laminating station of  FIG. 14  during work; 
           [0086]      FIG. 17  is a view in perspective of the laminating station of  FIG. 16 ; and 
           [0087]      FIG. 18  is a partial view in perspective of a heat-welding and cutting counterpart and/or a laminating counterpart. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0088]      FIG. 1  illustrates a machine  1  for treating a product  2  in a strip or web of material, which product  2  wound onto two unwinding reels  3  and  4 . The unwinding reels  3  and  4  are successively unwound gradually as the product  2  exits at the exit zone  5  where a subsequent workstation is usually provided, such as a station for cutting the product  2  to its width L in a plurality of strips of narrower width. 
         [0089]    In order to prevent overcomplicating the description of the invention and to make it easier for the reader to understand, the subsequent workstation is not shown. 
         [0090]    Once the product  2  stored on the unwinding reel  3  has been fully used, the initial end of the product  2  stored on the unwinding reel  4  is butt-joined with the final end of the product  2  of the unwinding reel  3 . This butt-joining operation is carried out by the butt-joining device  6  provided in the machine  1 . 
         [0091]    Once the butt-joining operation has been carried out, the unwinding reel  4  is unwound for the work of the subsequent workstation, which makes it possible, in concurrent operation time, to replace the used up unwinding reel  3  with a new unwinding reel. 
         [0092]      FIGS. 2 and 3  illustrate a butt-joining device  6  according to a first embodiment of the invention. This butt-joining device  6  comprises:
       a heat-welding and cutting workstation  7 , capable of heat-welding by ultrasound and of cutting two thicknesses of product  2  in a heat-welding and cutting zone,   a laminating workstation  8  with means  9  for laminating by ultrasound the heat-welding and cutting zone, between which said product  2  (not shown) is intended to be moved in a strip or web of material in a movement illustrated by the arrow  10 .       
 
         [0095]    More precisely, the heat-welding and cutting workstation  7  comprises means  7   a  for heat-welding-cutting with sonotrode  7   b  with a sharpened face  7   c.  The heat-welding and cutting workstation  7  also comprises a heat-welding and cutting counterpart  11  extending in a fourth direction of extension IVIV and with a substantially flat work face  11   a.    
         [0096]    The laminating workstation  8  comprises a laminating counterpart  12  extending in a third direction of extension IIIIII and with a substantially flat work face  12   a.  The laminating means  9  comprise a sonotrode  13  with a substantially flat face  15 . More precisely, the substantially flat face  15  is usually an adjusted face with slight convexity as it is more particularly shown in  FIG. 3 . 
         [0097]    The workstations  7  and  8  are oriented respectively in directions AA and BB of which the spacing d determines the distance separating the heat-welding and cutting workstation  7  and the laminating workstation  8 . 
         [0098]    The butt-joining device  6  according to the invention comprises means  16  for adjusting the relative position of the laminating means  9  and of the heat-welding and cutting zone to be laminated, such that, after heat-welding and cutting and after movement of the heat-welding and cutting zone to the laminating workstation  8  in the movement illustrated by the arrow  10 , the heat-welding and cutting zone to be laminated is placed in correspondence with the laminating means  9 . 
         [0099]    In the first embodiment of the invention, it is shown more particularly in  FIG. 3  that the adjustment means  16  comprise means for moving the laminating workstation  8  making it possible to move the laminating workstation  8  toward and away from the heat-welding and cutting workstation  7 . The adjustment means  16  also comprise locking means suitable for fastening the laminating workstation  8  at different distances d from the heat-welding and cutting workstation  7 . 
         [0100]    In practice, the laminating workstation  8  is supported by a support  17  designed to be secured to two positioning end-pieces  18   a  and  18   b  by means of screws (not shown) engaged in oblong fastening holes  19   a  to  19   d.  The oblong fastening holes  19   a  to  19   d  make it possible to move the laminating workstation  8  toward and away from the heat-welding and cutting workstation  7  in order to vary the distance d separating them. The screws designed to be engaged in the oblong holes  19   a  to  19   d  make it possible to lock the workstations  7  and  8  at a determined distance d of separation. 
         [0101]    In the case of  FIG. 3 , it can be seen that the heat-welding and cutting workstation  7  is also supported by a support  20  designed to be secured to positioning end-pieces  18   a  and  18   b  by means of screws (not shown) engaged in oblong fastening holes  21   a  to  21   d.  The heat-welding and cutting workstation  7  can thus be moved toward and away from the laminating workstation  8 . 
         [0102]    The adjustment means  16  make it possible to adjust the relative position of the heat-welding and cutting workstation  7  and the laminating workstation  8  such that, after movement of the product  2  (not shown) from the heat-welding and cutting workstation  7  to the laminating workstation  8 , the heat-welding and cutting zone to be laminated is placed in exact correspondence with the laminating means  9 . 
         [0103]    Once the distance d is adjusted for a type of product, the adjustment can be retained while the machine  1  treats a product  2  of the same kind with substantially identical mechanical characteristics. It is therefore possible to automate the butt-joining operations by means of an advance of product  2  that is predetermined and reproducible between the heat-welding and cutting workstation  7  and the laminating workstation  8  for which the distance d of separation has been adjusted. 
         [0104]    The use of the butt-joining device  6  of  FIGS. 2 and 3  will now be explained with the aid of the schematic  FIGS. 4 to 9  illustrating an operation for butt-joining the final end  20 ′ of a product  2 ′ originating from the unwinding of the unwinding reel  4  to the initial end  20 ″ of a product  2 ″ originating from the unwinding of the unwinding reel  3  in order to form a single, continuous product  2 . 
         [0105]    The device  6  comprises retention means  22  (not shown in  FIGS. 2 and 3 ) for retaining the product  2  upstream of the heat-welding and cutting workstation  7 , which means are capable of immobilizing an upstream section  2   a  of the product  2  extending from the retention means  22  to the heat-welding and cutting workstation  7 . To do this, it can be seen in  FIGS. 4 and 5  that the retention means  22  for retaining the product  2  upstream of the heat-welding and cutting workstation  7  comprise:
       a third deflection bar  23  for deflecting product  2 ,   pinching means  24  that can be moved selectively between a retention position ( FIG. 5 ) in which the pinching means  24  press on the third deflection bar  23  for deflecting product  2  by means of the product  2 , and a released position ( FIG. 4 ) in which the pinching means  24  are separated from the third deflection bar  23 .       
 
         [0108]    Prior to the butt-joining operations, the machine  1  is stopped so that the product  2 ′ no longer moves in the movement illustrated by the arrow  25 . The operator then takes hold of the end  20 ′ of the product  2 ′ to tension the product  2 ′ between the subsequent workstation (not shown) and a tensioning bar  26 . To do this, the tensioning bar  26  is furnished with means for coupling the end  20 ′ with the aid of spikes or any other appropriate means. A rotation of the tensioning bar  26  according to the movement illustrated by the arrow  27  makes it possible to tension the product  2 ′. 
         [0109]    The operator then puts the product  2 ″ in place, bringing its end  20 ″ onto a tensioning bar  28 . 
         [0110]    In order to prevent any movement of the unwinding reel  3  during the tensioning of the product  2 ′ with the tensioning bar  28 , the pinching means  24  are moved into retention position ( FIG. 5 ). The tensioning bar  28  is then turned in the movement illustrated by the arrow  29 : the upstream section  2   a  of product  2  extending from the retention means  22  to the heat-welding and cutting workstation  7  is thus tensioned and immobilized. 
         [0111]      FIG. 5  shows that the heat-welding and cutting counterpart  11  is then moved toward pressing means  30   a  and  30   b  in a translation movement illustrated by the arrow  31 . The pressing means  30   a  and  30   b  then press against the heat-welding and cutting counterpart  11  by means of two thicknesses of product  2 , namely the products  2 ′ and  2 ″. 
         [0112]    The heat-welding-cutting means  7   a  are then moved in the transverse direction CC across the width of the product  2  in order to carry out simultaneously the heat-welding and cutting operations. 
         [0113]    At the end of movement of the heat-welding-cutting means  7   a,  the heat-welding and cutting counterpart  11  is moved away from the pressing means  30   a  and  30   b  and reveals the configuration illustrated in  FIG. 6 . 
         [0114]    In this configuration, the products  2 ′ and  2 ″ are joined in a heat-welding and cutting zone  32 . 
         [0115]    The parts of products  2 ′ and  2 ″ situated on the other side of the heat-welding and cutting zone  32  are a waste product  33  which is cleared away. 
         [0116]    The product  2 ′ is then advanced by pulling in a translation movement illustrated by the arrow  25 , while the product  2 ″ is retained by the retention means  22 . 
         [0117]    The result of this is that the heat-welding and cutting zone  32  moves from the heat-welding and cutting workstation  7  toward the laminating workstation  8 . Because of the movement, the heat-welding and cutting zone  32  is slightly deformed by a partial flattening and thus forms a kind of crease  32   a  of which the strength by heat-welding is fragile and precarious. The heat-welding and cutting zone  32  must then be laminated to delete the crease  32   a  in order to obtain a heat-welding and cutting zone  32  that is substantially flat, even and of greater strength. 
         [0118]    In  FIG. 7 , it can be seen that the heat-welding and cutting zone  32  is placed in correspondence with the laminating means  9 . This relative position of the laminating means  9  and of the heat-welding and cutting zone  32  to be laminated is made reliable with the aid of the adjustment means  16  (not visible in  FIG. 7 ) which have been previously adjusted during tests such that, after heat-welding and cutting and after movement of the heat-welding and cutting zone  32  toward the laminating workstation  8 , the heat-welding and cutting zone  32  to be laminated is placed in correspondence with the laminating means  9 . 
         [0119]    The laminating of the heat-welding and cutting zone is then carried out. To do this, the laminating counterpart  12  is moved in a translation movement illustrated by the arrow  33  ( FIG. 8 ) until it comes to rest against pressing means  34   a  and  34   b  of the laminating workstation  8 . The laminating means  9  with sonotrode  13  are then moved in a transverse direction DD across the width of the product  2 ′ over the whole length of the heat-welding and cutting zone  32 . 
         [0120]    At the end of the movement of the laminating means  9 , the laminating counterpart  12  is moved away from the pressing means  34   a  and  34   b  and the pinching means  24  are moved into the released position. This then reveals the configuration illustrated in  FIG. 9 , in which the product  2 ′ is connected to the product  2 ″ by a heat-welding and cutting zone  32  that has been laminated. The product  2 ′ can then be drawn in the movement illustrated by the arrow  25  toward the subsequent workstation (not shown), which will then also draw the product  2 ″ toward the subsequent workstation while unrolling the unwinding reel  3 . 
         [0121]      FIG. 10  illustrates a second embodiment of adjustment means  16  which may be an alternative or may complement the first embodiment described with the aid of  FIGS. 2 and 3 . 
         [0122]    In  FIG. 10 , the butt-joining device  6  also comprises means  22  for retaining the product  2  upstream of the heat-welding and cutting workstation  7 , which means are suitable for immobilizing an upstream section  2   a  of product  2  extending from the retention means  22  to the heat-welding and cutting workstation  7 . 
         [0123]    The adjustment means  16  comprise a first deflection bar  35  for deflecting product, situated between the retention means  22  and the heat-welding and cutting workstation  7  and extending in a first direction of extension II perpendicular to the direction of travel of the product  2  (that is to say across the width of the product  2 ). 
         [0124]    The adjustment means  16  also comprise first transverse movement means of the first deflection bar  35 , which means are capable of moving the first deflection bar  35  so as to adjust the length of the upstream section  2   a  of product  2  extending from the retention means  22  to the heat-welding and cutting workstation  7 . 
         [0125]    In the case of  FIG. 10 , the first transverse movement means are suitable for moving the first deflection bar  35  in a rotary movement illustrated by the double arrow  36  about an axis EE offset from and parallel to the direction of extension II of said first deflection bar  35 . 
         [0126]    The adjustment of the adjustment means  16  that has to be carried out in advance consists in positioning, by rotation, the first deflection bar  35  in a position such that the length of the path followed by the upstream section  2   a  of product  2  extending between the retention means  22  (point A) and the heat-welding and cutting workstation  7  and more particularly to the heat-welding and cutting zone  32  that will be created (point B), is equal to the length of the path followed by the product between the retention means  22  (point A) and the laminating workstation  8  (point C) after advance of the product  2  in the movement illustrated by the arrow  37 . In other words, the position of the first deflection bar  35  is adjusted such that the length of product between the points A and B before advance of the product is equal to the length of product extending between the points A and C after advance of the product  2 . 
         [0127]    As an alternative to a rotary movement of the first deflection bar  35 , it is possible to arrange a movement via a translation movement. 
         [0128]    In  FIGS. 4 to 10 , the heat-welding and cutting zone  32  of the product  2  is moved from the heat-welding and cutting workstation  7  toward the laminating workstation  8  by means for advancing the product  2  of a subsequent workstation (not shown) situated downstream of the laminating workstation  8 . 
         [0129]    If the means for advancing the product  2  of the subsequent workstation are unsuitable for ensuring a determined, reliable and reproducible movement of the product  2  (for example due to great inertia), it is preferable to incorporate means for advancing the product  2  that are specific to the butt-joining device  6 . This also prevents having the subsequent workstation work at too low a speed during the movement of the heat-welding and cutting zone  32  toward the laminating workstation  8 . 
         [0130]    In a first variant, illustrated in  FIG. 11 , the butt-joining device  6  comprises accumulation means  38  that the product  2  traverses downstream of the laminating workstation  8 . The accumulation means  38  are suitable for moving by pulling the heat-welding and cutting zone  32  from the heat-welding and cutting workstation  7  toward the laminating workstation  8 . 
         [0131]    In  FIG. 11 , the product  2  traverses the accumulation means  38  in a zigzag path of which the length is adjustable. 
         [0132]    In the case of  FIG. 11 , the accumulation means  38  comprise three fixed bars  39   a  to  39   c  for deflecting product  2  and also comprise two bars  40   a  and  40   b  for deflecting product  2 , which bars are situated downstream of the laminating workstation  8  and extend in a second direction of extension IIII perpendicular to the direction of advance of the product  2 . Second means for the transverse movement of the second deflection bars  40   a  and  40   b  make it possible to move the latter so as to adjust the length of the section  2   b  of product  2  situated downstream of the laminating workstation  8 . 
         [0133]    In practice, the second deflection bars  40   a  and  40   b  are movable, in a movement illustrated by the arrow  41 , between a rest position (illustrated in dotted lines) in which they do not touch the product  2 , and an accumulation position (illustrated in solid lines) in which the second deflection bars  40   a  and  40   b  bring the product  2  into contact with the fixed deflection bars  39   a  to  39   c  in order to accumulate the product  2  on a zigzag path between the fixed deflection bars  39   a  and  39   c.    
         [0134]    Preferably, in the rest position of the second deflection bars  40   a  and  40   b,  the product  2  touches neither the second deflection bars  40   a  and  40   b  nor the fixed deflection bars  39   a  to  39   c  so as not to induce additional resistance to the advancing of the product  2  in the movement illustrated by the arrow  25 . 
         [0135]    The accumulation of the product  2  on its zigzag path between the deflection bars  39   a  to  39   c  and  40   a  and  40   b  makes it possible to pull the heat-welding and cutting zone  32  to correspond exactly with the laminating means  9  without having to move the product  2  downstream in the movement illustrated by the arrow  25 . 
         [0136]      FIG. 12  illustrates a second variant of the accumulation means  38  in which the accumulation means comprise only one second deflection bar  43  situated downstream of the laminating workstation  8  and extending in the second direction of extension IIII. The second transverse movement means are suitable for moving the second deflection bar  43  in a translation movement illustrated by the arrow  44 , which makes it possible to adjust the length of the section  2   b  of product  2  situated downstream of the laminating workstation  8  in order to pull the heat-welding and cutting zone  32  to be laminated to correspond exactly with the laminating means  9 . 
         [0137]    In  FIG. 12 , the section  2   b  of product  2  comes, after movement of the second deflection bar  43 , into contact with a fixed deflection bar  45 . This fixed deflection bar  45  is optional. 
         [0138]    In the first and second variants illustrated in  FIGS. 11 and 12 , the second deflection bars  40   a,    40   b  and  43  are moved in a translation movement. These second deflection bars  40   a,    40   b  and  43  could however be moved in a rotary movement about an axis that is offset from and parallel to their direction of extension IIII. This rotary movement of a second deflection bar is the subject of the third variant illustrated in  FIG. 13 . 
         [0139]    In this figure, the accumulation means  38  comprise two second deflection bars  46  and  47  situated downstream of the laminating workstation  8  and extending in a second direction of extension IIII perpendicular to the direction of advance of the product  2 . 
         [0140]    The second deflection bars  46  and  47  are connected to one another rigidly by a crossmember  48  mounted so as to pivot about an axis FF parallel to the second direction of extension IIII. In order to adjust the length of the section  2   b  of product  2  situated downstream of the laminating workstation  8 , the second deflection bars  46  and  47  are rotated about the axis FF in a movement illustrated by the arrow  49 . The second deflection bars  46  and  47  are thus moved from a rest position (in dotted lines) to an accumulation position (illustrated in solid lines). 
         [0141]    Adjusting the length of the section  2   b  of product  2  situated downstream of the laminating workstation  8  makes it possible to pull the heat-welding and cutting zone  32  to be laminated to correspond exactly with the laminating means  9 . 
         [0142]    In the first, second and third variants of  FIGS. 11 to 13 , it may be necessary to provide means (not shown) for retaining the product  2  downstream of the accumulation means  38 , or means for irreversibly advancing the product  2  from the subsequent workstation so that the product  2  cannot be moved in a movement illustrated by the arrow  42  during the operation of the accumulation means  38 . This makes it possible to avoid inducing inaccuracy in the advancement of the product  2  caused by the accumulation means  38 . 
         [0143]    During the lamination operation by the laminating means  9 , it is important that the product  2  is held between the laminating counterpart  12  and the substantially flat face  15  of the sonotrode  13 . 
         [0144]    However, because of the usually great length of the laminating counterpart  12 , the latter may have a curve and twisting deformations. 
         [0145]    It is therefore necessary to ensure that the sonotrode  13  follows as closely as possible the work face  12   a  of the laminating counterpart  12 , despite this possible curve and twist. 
         [0146]    To do this, as illustrated in  FIGS. 15 to 17 , it is provided that:
       the laminating workstation  8  comprises a laminating counterpart  12  extending in a third direction of extension IIIIII, with a substantially flat work face  12   a,      the laminating means  9  are secured to a support  50  that can be moved in the third direction of extension IIIIII facing the laminating counterpart  12 ,   the laminating means  9  are secured to bearing means  51  (in this instance rolling means  510 ) formed to press against the work face  12   a  of the laminating counterpart  12 ,   the laminating means  9  are secured to the support  50  by means of connecting means  52  formed to allow:
           a translation movement in a direction GG substantially perpendicular to the plane of the work face  12   a,      a rotary movement about a direction HH substantially parallel to the third direction of extension IIIIII.   
               
 
         [0153]    The sonotrode  13  of the laminating workstation  8  is thus capable of following the possible deformations of the work face  12   a  of the laminating counterpart  12  right along the laminating counterpart  12  as illustrated in  FIG. 16  in which the laminating counterpart  12 , having to occupy a theoretical position illustrated in dotted lines, in reality occupies the position illustrated in solid lines because of the deformations by bending and twisting. The support  50  remains oriented in the direction BB. 
         [0154]    In  FIGS. 14 and 17 , the rolling means  510  comprise two wheels  51   a,    51   b  situated on either side of the laminating means  9  so as to come, by means of the product (not shown), to rest against the work face  12   a  of the laminating counterpart  12  on either side of the heat-welding and cutting zone  32  (not shown) to be laminated. 
         [0155]    As is more particularly visible in  FIGS. 15 and 17 , the wheels  51   a  and  51   b  come respectively into contact with the laminating counterpart  12  by means of the product  2  (not shown) at two points  510   a  and  510   b  which define a direction of contact JJ defining a plane with the direction GG of orientation of the sonotrode  13 . Preferably, the bottom edge  61  of the substantially flat face  15  of the sonotrode  13  is included in the plane defined by the directions JJ and GG. In  FIG. 17 , the bottom edge  61  substantially coincides with the direction of contact JJ. 
         [0156]    It should be noted that a support and connecting means similar to the support  50  and to the connecting means  52  may also be used for the heat-welding and cutting workstation  7  of which the heat-welding and cutting counterpart  11  may also have deformations. 
         [0157]    As an alternative or to complement the particular connecting means  52  used for the laminating workstation  8  in  FIGS. 14 to 17 , it is possible to provide deformation means  53  of the work face  11   a,    12   a  of the heat-welding and cutting counterpart  11  and/or of the laminating counterpart  12 , as shown in  FIG. 18 . 
         [0158]    In this  FIG. 18 , the heat-welding and cutting counterpart  11  and/or the laminating counterpart  12  comprises a Tshaped cross section. In this instance, this Tshaped cross section is obtained by the connection of two section pieces  54   a  and  54   b.  As an alternative, the Tshaped cross section may be obtained by a single solid section piece. The work face  11   a  or  12   a  is supported by the outer face of the upper bar of the T formed by the section piece  54   b.    
         [0159]    The vertical bar of the T, formed by the section piece  54   a,  is kept clamped between two jaws  55   a  and  55   b  of a fixed retaining end-piece  56 . The clamping of the section piece  54   a  in the jaws  55   a  and  55   b  is provided by means of at least one clamping screw  57 . 
         [0160]    The deformation means  53  comprise two screws  58   a  and  58   b  designed to press against the vertical bar of the T formed by the section piece  54   a.    
         [0161]    The greater or lesser clamping of the screws  58   a  and  58   b  makes it possible to subject the heat-welding and cutting counterpart  11  and the laminating counterpart  12  to a torsional moment about the direction IIIIII or IVIV in order to straighten the work face  11   a  or  12   a  deformed by a preexisting deforming twist. 
         [0162]    It should be noted that the deformation means  53  may preferably comprise a retaining end-piece  56  identical to that of  FIG. 18  at each of the ends of the heat-welding and cutting counterpart  11  or of the laminating counterpart  12 . 
         [0163]    As an alternative or as a complement, the deformation means  53  may comprise adjusting screws designed to press against the undersides  59   a  and  59   b  of the heat-welding and cutting counterpart  11  or of the laminating counterpart  12  in order to generate a pressure in the sense and direction defined by the arrow  60 . Such deformation means  53  make it possible to induce on the heat-welding and cutting counterpart  11  or on the laminating counterpart  12  a deformation that compensates for a preexisting curve. It should be noted that the pressure illustrated by the arrow  60  is necessarily at a distance from the third or fourth directions of extension IIIIII and IVIV and may therefore also induce on the heat-welding and cutting counterpart  11  or on the laminating counterpart  12  a twist which compensates for a preexisting inverse twist. 
         [0164]    It is explicitly specified that the support  50  and the particular connecting means  52  illustrated in  FIGS. 14 to 17  constitute an invention independent of the adjustment means  16 . This support  50  and these connecting means  52  may be used in a laminating workstation  8  or in a heat-welding and cutting workstation  7 . 
         [0165]    Similarly, the deformation means  53  illustrated in  FIG. 18  constitute an invention independent of the adjustment means  16 . 
         [0166]    The expression “deflection bar” means any longitudinal body of any section against which the product can press, and may notably comprise a roller capable of rotating about its direction of extension. 
         [0167]    The present invention is not limited to the embodiments that have been explicitly described, but it includes the various variants and generalized applications contained in the field of the following claims.