Abstract:
A method for folding a textile strip length, including the steps of first holding the strip length firmly close to an auxiliary folding edge whose direction is parallel to a definitive folding edge, folding a part of the strip around the auxiliary folding edge substantially perpendicular to the plane of the strip length to form a definitive fold, gripping an end of the part of the strip folded around the auxiliary folding edge, compressing the part of the strip against a clamping surface arranged substantially co-planar with the plane of the strip length and belonging to a clamping element forming the definitive fold, and smoothing and fixing the folded part of the strip lying substantially in the plane of the strip length between the clamping surfaces arranged substantially in the plane of the strip length.

Description:
This is a U.S. national stage of application No. PCT/CH01/00041, filed on Jan. 19, 2001. Priority is claimed on that application and on the following applications: Country: Switzerland, Application No.: 440/00, Filed: Mar. 7, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a method for folding a textile strip length, in particular a strip length for a label and to an installation for carrying out the method. 
     PRIOR ART 
     Methods and installations of the type mentioned at the beginning are known, for example from IT-1 268 836 B. In the method described there and the installation for carrying it out, a strip length is first held firmly close to an auxiliary folding edge which is to be formed and whose direction is parallel to the definitive folding edge. The part of the strip which projects reaches over a gap formed by two clamping elements, the clamping surfaces of which being aligned perpendicular to the plane of the strip lengths. A flat blade pushes this part of the strip into the gap, forming a fold, and then has to be withdrawn again before the fold formed can be smoothed and fixed by pressing the clamping surfaces against each other. Here, the problem arises that when the blade is pulled out, the fold formed is easily changed or even destroyed. Even when the fold is smoothed and fixed properly, there is the further disadvantage that this fold around the auxiliary folding edge is aligned perpendicular to the plane of the strip. By means of the smoothing and fixing operation, this auxiliary fold is also firstly fixed, so that in the finally folded strip length the folded parts of the strip project at right angles to the plane of the strip lengths, which is undesired and as a rule makes post-processing of the folded strip lengths necessary. 
     U.S. Pat. No. 3,148,874 A discloses another method and another installation for folding a textile strip length, the strip length firstly being held firmly by means of an L-shaped holding element beside a folding edge to be formed. The projecting part of the strip is firstly folded by means of a folding element at right angles to the plane of the strip length and then turned over a holding foot of the L-shaped holding element, parallel to the plane of the strip length. The holding foot of the L-shaped holding element then has to be withdrawn again before the fold formed is smoothed and fixed by pressing clamping surfaces, which are aligned parallel to the strip length, against each other. Although the fold formed already lies in the plane of the strip length, the problem also results here that when the holding foot is withdrawn, the fold formed can easily be changed or even destroyed. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to improve a method and an installation for folding a textile strip length, in particular a strip length for a label, in such a way that the aforementioned disadvantages no longer occur. 
     a) a method as claimed in claim  1 ; and 
     b) an installation for carrying it out as claimed in claim  2 . 
     Pursuant to this object, and others which will become apparent hereafter, one aspect of the present invention resides in a method for folding a textile strip length by first holding the strip length firmly close to an auxiliary folding edge whose direction is parallel to a definitive folding edge, folding a part of the strip around the auxiliary folding edge substantially perpendicular to the plane of the strip length to form a definitive fold, gripping an end of the part of the strip folded around the auxiliary folding edge, compressing the part of the strip against a clamping surface arranged substantially co-planar with the plane of the strip length and belonging to a clamping element forming the definitive fold, and smoothing and fixing the folded part of the strip line substantially in the plane of the strip length between the clamping surfaces arranged substantially in the plane of a strip length. 
     The fact that the strip part angled over around an auxiliary folding edge is gripped and compressed and therefore folded against a clamping surface which is aligned substantially coplanar with the plane of the strip section results in two critical advantages. Since, during the compression, the compression tool does not engage in the fold or a gap between the clamping elements, it can remain in use until the clamping surfaces have gripped and fixed the folds, so that exact alignment and shaping of the folds is always provided, and slipping is undoubtedly prevented. Furthermore, the clamping surfaces rise substantially in the plane of the strip length, so that the folded, smoothed and fixed folds of the strip length likewise lie in the plane of the strip length and the auxiliary folded edge is eliminated, so that a satisfactory, flat, folded strip length is produced and post-treatment is no longer necessary. 
     In order to carry out the method, various installations are conceivable. For example, it is possible for support elements, on which strip sections rest for processing, to be arranged at rest and for folding and clamping tools to be moved against the resting support die. A particularly advantageous installation for folding the textile strip length includes a support element for the strip length to be folded, which support element has a support surface aligned parallel to the strip length and an auxiliary folding edge aligned parallel to a folding edge to be created. The installation further has a holding element arranged to cooperate with the support surface of the support element for the strip length. A folding element is provided for forming a fold of the strip length between clamping surfaces of two clamping elements for smoothing and fixing the fold. The clamping surfaces of the clamping elements are aligned substantially co-planar with a plane of the strip length to be folded. The auxiliary folding edge has a supporting surface aligned substantially perpendicular to the support surface of the support element. The folding element has a compression edge arranged to cooperate with the supporting surface of the auxiliary folding edge so as to grip an end of the part of the strip to be turned over against the supporting surface into a compressed part of the strip against the clamping surface of one of the clamping elements to form the definitive fold. 
     For the folding of the part of the strip projecting beyond the support surface of the support element, various possibilities result. For example, the support element can be arranged at rest and the holding element, which can be biased, can be biased against the support surface. An appropriate folding element can then be moved along the support element in order to turn over the projecting part of the strip against the supporting surface. By contrast, in a particularly preferred solution the support element together with the holding element that can biased against the support surface are movable into and out of a holding position for the strip length. 
     In addition, diverse possibilities result for the configurations of the folding element. For example, a spatula can be moved over the auxiliary folding edge of the support element and along the supporting surface in order to turn the projecting part of the strip over against the supporting surface. However, in a particularly advantageous embodiment the folding element has an oblique run-on surface which, during a relative movement between support element and folding element, turns over a part of the strip which projects beyond the support surface around the auxiliary folding edge and against the supporting surface. In order to permit reliable turnover, the support element and the folding element are biased toward each other. 
     It is particularly expedient if the folding element is also designed as a clamping element, against which the other clamping element is biased. This biasing can be produced by various means, for example by electromagnetic or fluid-actuated means. However, biasing by means of a spring is particularly advantageous. This also makes it easier to raise the clamping element by means of the support element, which can be moved in relation thereto. 
     The holding element can be biased against the support element by a bias spring and can be moved by the support element into an initial position in which the holding element is latched by a releasable latch. In one embodiment, the holding element is set back with respect to the auxiliary folding edge of the support surface of the support element, and the support surface cooperates with the clamping element arranged to project beyond the folding element by means of the auxiliary folding edge so as to raise the clamping element off the folding element as the support element is moved out. 
     In a further embodiment of the invention, at least one of the clamping elements is provided with a heating element. 
     In another embodiment of the invention a folding station, a conveying device and an unloading station are provided. The support element and the holding element are arranged in a stationary manner on the folding station and the folding element with the clamping element is arranged on the conveying device which can be moved from the folding station to the unloading station. This construction permits a continuous operation of the installation. The conveying device can be provided with a plurality of folding elements and clamping elements distributed over its length. In order to drive the conveying device, an extremely wide range of materials can be used, for example a stepping motor, a standard motor with limit-switch control, a Maltese-cross drive or the like. 
     In principle, it is possible to construct the installation in such a way that a strip length is provided with a fold only at one end. In the case of labels, however, two folds are desired at the two ends. This two-fold operation can be accomplished using two tool sets wherein one tool set is a mirror image of the other tool set. In order to be able to set the installation to strip lengths of different lengths, one set of tools is arranged such that it can be displaced relative to the other set, in order to be able to set the mutual spacing to the desired length of the strip lengths. 
     The installation expediently has a delivery device for the strip lengths to the support element. Such a delivery device is advantageously configured in order to supply a continuous strip, from which strip lengths are severed at an appropriate severing device. According to a further embodiment, the feed device can be equipped with a conveying element, in which the lengths of the strip lengths to be severed can be set. An installation which is particularly capable of adaptation results if the severing device has both a mechanical cutting device and a thermal cutting device, for example an infrared or ultrasonic cutting device, which can be used as desired. 
     The installation in another embodiment is expediently equipped with a stacking device for the folded strip lengths, it having proven to be advantageous to provide a magazine, in which the folded strip lengths can be moved against a displacement resistance and can be held. 
     It is also advantageous that both the method and the installation are suitable for an extremely wide range of folds, for example, not just for the production of strip lengths with one or two end folds but also for producing strip lengths with a center fold. Even the production of strip lengths with a diagonal fold is conceivable. This is possible since folding is carried out merely by means of a compression operation against a flat clamping surface which, moreover, is aligned substantially in or parallel to the plane of the strip lengths, so that folding can be carried out at any desired point on the strip length and with any desired alignment of the auxiliary folding edge. This makes it possible to use only simple tools which, on one and the same installation, can also readily be replaced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention will be described in more detail below using schematic drawings, in which: 
     FIG. 1 shows an installation for folding a textile strip length, in particular a strip length for a label in plan view; 
     FIG. 2 shows the installation of FIG. 1 in side view; 
     FIGS. 3 a  to  3   c  show the folding station of the installation according to FIG. 1 in detail, in longitudinal section and in various operating positions; 
     FIGS. 4 a  to  4   h  show the principle of the folding at the folding station according to a schematic representation and in various intermediate stages from the insertion of a strip length until the deposition of the folded strip length; 
     FIG. 5 shows an outline of the folding station for producing a strip length with center fold; 
     FIG. 6 shows the folding station according to FIG. 5 in longitudinal section; 
     FIG. 7 shows an outline of the folding station for producing a strip length with diagonal fold; and 
     FIG. 8 shows the folding station of FIG. 7 in longitudinal section. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show a schematic representation of an installation for folding a textile strip length, in particular a strip length for a label. The installation includes a delivery device  2 , at which strip lengths  8  are severed from an endless strip  4  by means of a severing device  6  and are fed to a folding station  12  by means of a transfer device  10 . At the folding station  12 , the strip lengths  8  are folded at the ends and the folded strip lengths  8   a  are held firmly on clamping tools  14  of a carousel-like conveying device  16 , which is rotatably mounted over a shaft  15 . The folded strip lengths  8   a  are thus conveyed onward from the folding station  12  to an unloading station  18 , where they are transferred by means of lever arms  20  to a magazine  22  of a stacking device  24 . The lever arms  20 , which are mounted such that they can rotate about a pivot  26 , are actuated by means of an actuator  28  and discharge the folded strip lengths  8   a  to the magazine  22  against a displacement resistance  30 . 
     The delivery device  2  contains a feed device  31  with a feed table  32 , on which an endless strip  4  from a supply roll, not specifically illustrated, is fed by means of a conveying element  34  to the severing device  6  in the desired length of the strip length. The conveying element  34  can be, for example, a conveying arm moving back and forth or a driven conveying roll. The strip length to be conveyed is to be determined by a sensor  36 , which responds to strip marks on the strip  4  supplied. In addition, inspection means (not specifically illustrated) for determining strip faults can also be associated with the feed table  32 . The severing device  6  contains a thermal cuffing device  6   a , for example an infrared or ultrasonic cutting device  6   a , and a mechanical cutting device  6   b , which can come into use as desired, depending on the material characteristics of the strip to be treated. The transfer device  10  between the severing device  6  and the folding station  12  has firstly, after the severing device  6 , a conveying arm  40  which is driven in oscillation by means of a drive  38 , for example a fluid-actuated piston/cylinder unit, which arm transfers the strip length  8  from the severing device  6  to a rail  42 . The latter is driven back and forth by means of an oscillating drive  44  in order to feed the strip length to the folding station, as emerges from FIG. 4 a.    
     One half of the folding station is illustrated schematically in FIGS. 3 a  to  3   c . A second half, which is of identical construction, exists as a mirror image of this, as emerges from  4   a  to  4   h . The folding station  12  contains a support element  46 , which is arranged on a carriage  50  such that it can be pivoted about an axis of rotation  48 , said carriage  50  being mounted in the machine frame  52  such that it can be moved up and down. A bias spring  54  biases the support element  46  into the vertical basic position. On the upper side, the support element  46  contains a support surface  56 , to which the strip length  8  to be treated is transferred by means of the rail  42  and deposited (FIG. 4 a ). A holding element  60  biased against the support surface  46  by means of a spring  58  holds the strip length  8  firmly on the support element  46  (FIG. 4 b ). The support element  46  also has an auxiliary folding edge  62 , which is aligned parallel to the folding edge ( 96  in FIG. 4 g ) of the fold to be produced ( 94  in FIG. 4 g ) and around which the part  64  of the strip projecting beyond the support surface can be folded against a supporting surface  66  adjoining the auxiliary folding edge  62  (FIGS. 4 c  and  4   d ). The supporting surface  66  is aligned substantially perpendicular to the support surface  56 . The support element  46  can be moved by means of a drive  68  shown in FIG. 2, for example a fluid-operated piston/cylinder unit, from the basic position shown in FIGS. 3 a  and  4   b  into the folding position shown in FIGS. 3 b  and  4   d . In the process, the support element  46  comes into contact with the inclined run-on surface  70  of a folding element  72 , which turns over the part  64  of the strip against the supporting surface  66  (FIGS. 3 b ,  4   c  and  4   d ). At the same time, a clamping element  74  is raised, which is arranged above the folding element  72  such that it can be pivoted and is biased by means of a spring  76  against the folding element  72  which, at the same time, is also designed as a clamping element  73 . Tn order to permit the clamping element  74  to be raised, the holding element  60  is set back with respect to the auxiliary folding edge  62  of the support element  46 , so that the support element  46  can interact with the clamping element  74  projecting beyond the folding element  72  or clamping element  73 . 
     In the folding position shown in FIG. 3 b , the holding element  60  latches by means of an opening  78  onto a latching pin  80 , which is biased into this latching position by means of a spring  82 . The latching pin  80  can be pulled back from the locking position by means of an actuator  84 . The holding element  60  is guided such that it can be displaced on a rail  86  by rollers  88 , the rail  86  being connected in a fixed position to the machine frame  52 . 
     The definitive formation of a fold is carried out in accordance with FIGS. 4 d  to  4   f , as follows. The folding edge  72  has a compression edge  90  which, as FIG. 4 d  reveals, co-operates with the end of the part  64  of the strip turned over against the supporting surface  66 , the supporting surface  66  biased against the folding element  72  by means of the bias spring  54  reinforcing the engagement between the compression edge  90  and the part  64  of the strip. The support element  46  is then pulled back into the initial position, the compression edge  90  of the folding element  72  compressing the projecting part  64  of the strip against the clamping surface  92  of the clamping element  74  and, in the process, forming the definitive fold  94  with the folding edge  96 , which lies in the plane of the strip length  8   a , as revealed by FIGS. 4 e  and  4   f . In the process, the fold  94  is clamped in between the clamping surfaces  92  of the clamping element  74  and the clamping surface  98  of the folding element  72 , which at the same time is also designed as a clamping element  73 , said elements being aligned coplanar with the plane of the strip length (FIGS. 4 e  and  4   f ). The clamping element  73  contains a heating element  100 , in order to smooth the fold  94  clamped in between the clamping surfaces  92 ,  98  and to fix it in the turned-over form (FIG. 4 g ). Smoothing and fixing are carried out during the conveying movement of the carousel-like conveying device  16  from the folding station  12  to the unloading station  18  (FIGS. 4 f  to  4   h ). There, the folded strip length  8   a  is transferred into the magazine  22  of, the stacking device  24  by means of the lever arms  20  with the clamping elements  73 ,  74  open. 
     In order to be able to set the installation to tape lengths of different lengths, the installation, as already mentioned, is constructed from two halves  102 ,  104 , which can be displaced relative to each other, as indicated by the displacement arrow  106  in FIG.  1 . 
     FIGS. 5 and 6 show the use of the installation for producing a label with a center fold. For this purpose, the strip length  8  is placed on the support elements  46 ,  46  in such a way that the strip length  8  rests with about half its length on the auxiliary folding edge  62 . The folding operation can then be carried out as hitherto, the folding edge  96   a  of the center fold being located at half the length of the strip lengths. 
     FIGS. 7 and 8 show the modification of the installation for producing strip lengths with diagonal folding. To this end, the tools, that is to say the support elements  46   a  with the auxiliary folding edges  62   a , the holding elements  60   a , the folding elements  72   a  and the clamping elements  73   a ,  74   a  are aligned parallel to the diagonal folding edges  96   b  to be produced. The folding operation is then likewise carried out again in a manner analogous to FIGS. 4 a  to  4   h.    
     LIST OF DESIGNATIONS 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                  2 
                 Delivery device 
               
               
                   
                  4 
                 Strip 
               
               
                   
                  6 
                 Severing device 
               
               
                   
                  6a 
                 Thermal cutting device 
               
               
                   
                  6b 
                 Mechanical cutting device 
               
               
                   
                  8 
                 Strip length 
               
               
                   
                  8a 
                 Folded strip length 
               
               
                   
                  8b 
                 Folded strip length 
               
               
                   
                  8c 
                 Folded strip length 
               
               
                   
                  10 
                 Transfer device 
               
               
                   
                  12 
                 Folding station 
               
               
                   
                  14 
                 Clamping tool 
               
               
                   
                  15 
                 Shaft 
               
               
                   
                  16 
                 Carousel-like conveying 
               
               
                   
                   
                 device 
               
               
                   
                  18 
                 Unloading station 
               
               
                   
                  20 
                 Lever arm 
               
               
                   
                  22 
                 Magazine 
               
               
                   
                  24 
                 Stacking device 
               
               
                   
                  26 
                 Pivot 
               
               
                   
                  28 
                 Actuator 
               
               
                   
                  30 
                 Displacement resistance 
               
               
                   
                  31 
                 Feed device 
               
               
                   
                  32 
                 Feed table 
               
               
                   
                  34 
                 Conveying element 
               
               
                   
                  36 
                 Sensor 
               
               
                   
                  38 
                 Drive 
               
               
                   
                  40 
                 Conveying arm 
               
               
                   
                  42 
                 Rail 
               
               
                   
                  44 
                 Drive 
               
               
                   
                  46 
                 Support element 
               
               
                   
                  46a 
                 Support element 
               
               
                   
                  48 
                 Axis of rotation 
               
               
                   
                  50 
                 Carriage 
               
               
                   
                  52 
                 Machine frame 
               
               
                   
                  54 
                 Bias spring 
               
               
                   
                  56 
                 Support surface 
               
               
                   
                  58 
                 Spring 
               
               
                   
                  60 
                 Holding element 
               
               
                   
                  60a 
                 Holding element 
               
               
                   
                  62 
                 Auxiliary folding edge 
               
               
                   
                  62a 
                 Auxiliary folding edge 
               
               
                   
                  64 
                 Part of strip 
               
               
                   
                  66 
                 Supporting surface 
               
               
                   
                  68 
                 Drive 
               
               
                   
                  70 
                 Run-on surface 
               
               
                   
                  72 
                 Folding element 
               
               
                   
                  72a 
                 Folding element 
               
               
                   
                  73 
                 Clamping element 
               
               
                   
                  73a 
                 Clamping element 
               
               
                   
                  74 
                 Clamping element 
               
               
                   
                  74a 
                 Clamping element 
               
               
                   
                  76 
                 Spring 
               
               
                   
                  78 
                 Opening 
               
               
                   
                  80 
                 Latching pin 
               
               
                   
                  82 
                 Spring 
               
               
                   
                  84 
                 Actuator 
               
               
                   
                  86 
                 Rail 
               
               
                   
                  88 
                 Roll 
               
               
                   
                  90 
                 Compression edge 
               
               
                   
                  92 
                 Clamping surface of 74 
               
               
                   
                  94 
                 Definitive fold 
               
               
                   
                  96 
                 Folding edge 
               
               
                   
                  96a 
                 Folding edge 
               
               
                   
                  96b 
                 Folding edge 
               
               
                   
                  98 
                 Clamping surface of 73 
               
               
                   
                 100 
                 Heating element 
               
               
                   
                 102 
                 Half 
               
               
                   
                 104 
                 Half 
               
               
                   
                 106 
                 Displacement arrow