Patent Publication Number: US-9409370-B2

Title: Device for producing bags from hose-shaped material

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a national stage of PCT/EP10/050396 filed Jan. 14, 2010 and published in German, which claims the priority of German number 10 2009 000 454.8 filed Jan. 28, 2009, hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The invention relates to an apparatus for producing bags from tubular material comprising fabric made of stretched plastic strips. The apparatus has at least one tube-forming device or a tube-unwinding device, by which tubular material, for producing bar can be produced from web-shaped material and in which the tubular material can he conveyed in a transport direction (x′), and at least one tube-separating device, by which tube pieces can be separated from the tubular material, and a bottom-forming device, by which bottoms can be molded onto at least one end of a tube piece, and at least one transport device for transporting the tube pieces within the bottom-forming device in a transport direction (x) extending transversely to their direction of extension (y). The invention also relates to a method of producing bags from web-shaped material with the help of at least one tube-forming device or a tube-unwinding device. In the method, the tubular material is conveyed in a transport direction (x′), and tube pieces are separated from the tubular material with the help of at least one tube-separating device. Bottoms are molded onto at least one of a tube piece in a bottom-forming device, and the tube pieces are transported within the bottom-forming device with the help of at least one transport device in a transport direction (x) extending transversely to the direction of extension (y) of the tube pieces. 
     2. Description of the Prior Art 
     Such apparatuses are known in the prior art and have been available on the market for quite a while now. These apparatuses usually first comprise a tube-forming device for producing and providing tubular material. Provision can also be made for only a tube-unwinding device. This device can usually be equipped with a spool, on which tubular material is wound. The material is mostly drawn off continuously from this spool in the longitudinal direction. 
     In the bag-making process carried out on machines known in the prior art, the fabric tube provided by the tube-forming device or the tube-unwinding device is supplied to the cross cutter that separates the fabric tube into individual tube pieces. The tube pieces are transferred to a transport device. The original transport direction, in which the tube or the tube pieces are transported in the direction of their longitudinal axes, is altered with the help of this transport device to a new transport direction so that the tube pieces are no longer transported in the direction of their longitudinal axes, but instead transversely thereto so that the ends of the tube pieces can be reached laterally for the purpose of molding the bottoms. The original and the new transport directions of the tube or the tube piece are located at right angles to each other. 
     As mentioned above, the tubular fabric material that can additionally be coated is separated into tube pieces. When producing the tube pieces, the tube is drawn cyclically in its longitudinal direction by the length of each tube piece. In order to enable the cyclical drawing of the tube, there is a compensating device provided in the form of at least one movable deflecting rod provided between the spool of material and the separating device. A tube piece is then isolated, thus separated, from the tube. This step is usually carried out by means of a cutting tool such as a blade. Other separation processes and the associated devices are also feasible. The aforementioned spool of material often comprises a fabric tube made of circular woven material. The tube produced on a circular loom is collapsed after its production and provided with a coating that ensures that portions of the tube piece can be heat-sealed together without damaging the stretched fabric and affecting its strength adversely. 
     The tube-forming device molds tubular material in that the edges of the material web are placed on top of each other and joined together, for example, by means of a plastic extrusion. In this process, both the flat material web and the tube are transported in the longitudinal direction. The tubular material is made of two superimposed material webs, each of which can comprise a number of layers. The aforementioned tube-forming device can further be able to insert side gussets. Bags provided with side gussets are advantageous when they are to be stacked in the filled state. The major advantage in producing tubes from woven and coated flat material is that coating material does not protrude laterally over the edges of the flat tube, as is often the case when collapsed, circular woven tubular material is coated. Protruding coating material frequently results in errors when producing bags from pieces of the tubular material. 
     The tube piece produced in the manner described above is received by at least one transport device in order to deliver them to the individual processing stations. After being separated from the tubular material, the tube pieces are no longer transported further in the longitudinal direction, but instead in the transverse direction. The term “transverse direction” is understood to mean that the tube pieces are now transported in a direction extending transversely to their longitudinal extension in order to obtain unobstructed access to both ends of the tube pieces in the further steps carried out for producing bags. 
     The individual processing stations used in the bag-making process are listed below together with an explanation of their functions.
         In an optionally provided pre-creasing station, form punches are lowered onto the tube piece for producing fold lines. The turned-in corners of the opened tube bottom will later be located on these fold lines. The form punches can also be heated for this purpose.   In the bottom-opening station, at least one end of a tube piece is raised so that a bottom can be molded onto this raised end. The turned-in corners are located on the fold lines of the tube piece. Due to its geometric shape, the bottom opening is also called the bottom square. It should be noted here that the shape of the bottom opening is not square, but rectangular in most cases. Both ends of a tube piece are usually processed in a similar manner.   In the valve patch station, a valve patch is applied to the previously opened bottom of the tube piece. The valve patch enables the finished bag to be filled later with the help of a suitable fill nozzle.   In a so-called closing station, parts of the bottom openings or the bottom squares, the so-called tabs, are folded back on both sides toward the folded edge. In doing so, portions of these tabs can overlap each other, and these overlapping portions of these tabs can be joined together.   A bottom patch is then attached, for example heat-sealed to the folded bottom opening in the bottom patch station.       

     It should be mentioned here that all the stations listed above need not be present in an apparatus for producing bags. It is thus possible to dispense with a pre-creasing station. It is also not required to always apply bottom patches in order to produce a bag. Nonetheless, the apparatus may also comprise additional processing stations. As mentioned above, in the bag-making process carried out on bag-making apparatuses known in the prior art, the fabric tube provided by the tube-forming device is supplied to the cross cutter that separates the fabric tube into individual tube pieces. The tube pieces are transferred to a transport device. The original transport direction, in which the tube or the tube pieces are transported in the direction of their longitudinal axes, is altered with the help of this transport device to a new transport direction so that the tube pieces are no longer transported in the direction of their longitudinal axes, but instead transversely thereto so that the ends of the tube pieces can be reached laterally for the purpose of molding the bottoms. The original and the new transport direction of the tube or the tube piece are located at right angles to each other. It is for this reason that the tube-forming device and the aforementioned processing stations are also disposed or set up so as to extend at right angles to each other. 
     The arrangement of the tube-forming device so as to extend at right angles to the processing stations is disadvantageous. The floor space of production halls is usually rectangular, and therefore such an arrangement of devices takes up space. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to suggest an apparatus for producing bags from tubular material, which apparatus can be set up in a more space-saving manner. 
     According to the invention, this object is achieved by the features of the invention described herein. 
     Thus the transport direction of the tubular material in the tube-forming device and the transport direction of the tube pieces in the transport device are oriented so as to extend parallel to each other. The term “parallel” can be understood to mean that the transport directions are oriented so as to extend in the opposite or same direction. The former option is interesting if an elongated, narrow factory work room is available. The second option is recommended for rather broad but short factory work rooms. The term “parallel” is further understood to mean the horizontal component of the direction of movement. A vertical component of movement remains unaffected thereby. 
     The tube-forming device conveys the tubular material along the longitudinal axis of the tube. Since the processing stations have to reach the ends of the individual tube pieces, it is advantageous to transport the tube pieces to the processing stations in a direction extending transversely to their longitudinal axes. Therefore it is particularly advantageous if at least one deflecting device is provided between the tube-forming device and the bottom-forming device, by means of which deflecting device the tubular material can be deflected upstream of the cross cutter in a new transport direction which extends, at least in part, transversely to the original transport direction. Thus the tube can already be conveyed in the direction that corresponds to the position of the tube pieces that is required for the subsequent processing of the tube pieces. By contrast, it would be possible to separate the tube in the transport direction to form tube pieces and to rotate these tube pieces individually or in groups, which, however, is time-consuming and thus expensive as compared to the solution suggested by the invention. The deflected tube can then be separated into individual tube pieces that are now supplied to the processing stations in a direction of movement extending transversely to their longitudinal axes. A tube-unwinding device can also be provided according to the present invention. 
     In a particularly preferred embodiment of the invention, the position of the deflecting device that enables a deflection of the tubular material can be altered. More particularly, the deflecting device can be moved in the original transport direction of the tubular material. The advantage of this feature is that the position of the edges of variably broad material tubes can be adjusted to suit the cross cutter or the separating device. Particularly in the case of tubes produced in a tube-forming device, the central position is identical in most cases, irrespective of the width of the tube. However, the transport device collects the tube pieces at their front lateral edges so that it is not the centerline but the front edges that must assume a constant position irrespective of the width of the tube. This is achieved very easily as a result of the movability of the deflecting device. Nonetheless, it is feasible to provide a number of deflecting elements, the inclination angle of which is alterable relative to the transport direction of the tubular web. The position of the front edges of the tubes can also be adjusted in this way. 
     Advantageously, the deflecting device is an air turning bar known per se. The air turning bar can comprise bores, upon which air acts so that the tubular material can be guided by means of the turning bar without coming into contact with the same. 
     In a preferred embodiment of the invention, the separating device and the deflecting device are located at a distance from each other in the vertical direction. Preferably, the deflecting device is located above the separating device. The deflecting device can also be positioned below the separating device. This enables the tube-forming device and the additional tube piece-processing stations to be set up or disposed directly one behind the other—in a line. In this case, the geometric centerlines of the tubes and the tube pieces are also located in a line, which likewise prevents space from being used up unnecessarily. More particularly, the arrangement of the deflecting device below the separating device enables the transport direction of the tube to be altered by means of only one deflecting device disposed obliquely in the transport direction of the tube. It is particularly advantageous if the deflecting device is disposed above the separating device. The tubes can be guided at the level of the separating device by means of transport rollers, the rotation axes of which are disposed so as to extend transversely to the transport direction of the tube. 
     In a further preferred embodiment of the invention, the tube-forming device comprises a storage device disposed upstream of the deflecting device in the transport direction of the tube. Tubular material that was produced beforehand by the tube-forming device can be stored by means of the storage device. Thus, for example, in the case of a malfunction of the tube-forming device or in the case of a change of the material spool, the individual processing stations (more particularly, the tube-separating device) can continue to be supplied with tubular material without having to stop the process of bag production. It is also possible, within certain limits, to store additional tubular material if it becomes necessary to stop the processing stations. 
     In a further advantageous embodiment, the tube-forming device comprises a winding unit, by means of which the tubular material produced beforehand can be wound up into a spool. The tube-forming device can operate in an off-line mode—that is, without the supply of tubular material to the processing stations. 
     In the off-line operation, the processing stations can also be fed by a tube-unwinding device with tubular material. The unwinding device comprises a spool of tubular material and is not connected to the tube-forming device. The spool of material can be produced beforehand by the tube-forming device. 
     Thus the apparatus for producing bags can be operated in two alternative modes. In the so-called in-line operation, the cross cutter is supplied directly by the tube-forming device with tubular material. In the off-line operation, the apparatus for producing bags—as described above—is supplied with material from a separate spool of tubular material that can be produced by the tube-forming device in the manner described above. In this way, the aforementioned components of the apparatus for producing bags can be operated with the maximum flexibility possible. This flexibility is required particularly, for example, when carrying out maintenance work on individual components of the apparatus for producing bags. 
     In a further preferred embodiment, the tube-forming device comprises a device for the detection of material defects. Defective tube regions can be detected by the device for detecting material defects. The defective regions of the tube can include seams thereof that are leaky. These leaky seams can result, for example, when the edges of the material webs are glued together erroneously in the tube-forming device. Defective tube regions can also include faults in the fabric or errors in the coating of the flat material that is made into the tubular material. An incorrect width of a tube can also be recognized as a defective tube region. 
     It is advantageous if a reject gate is provided downstream of the tube-separating device in the transport direction of the tubular material. Tube pieces comprising defective regions can be removed by means of this reject gate. 
     In a further advantageous embodiment of the invention, a control device is provided, to which data can be fed from the device for the detection of material defects by means of a suitable data line. These data include information on the defective regions of the tubular material described above. 
     Advantageously, the device for detecting material defects is disposed upstream of the separating device. Advantageously, the reject gate is located directly downstream of the tube-separating device. 
     Advantageously, the reject gate is activated by the control device when the device for detecting material defects detects a defective region (and transmits information about the same to the control device) and the tube section in question has been separated. The reject gate now receives the tube section instead of the transport device. In this case, the defective tube piece is eliminated before it can travel to the individual processing stations and be processed to form a bag. This timely elimination of defective tube pieces can therefore save a good deal of energy and time since defective tube pieces are not processed to form bags. 
     Additional exemplary embodiments of the invention are explained below in the present description and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the individual figures: 
         FIG. 1  is a schematic diagram of an apparatus for producing fabric bags 
         FIG. 2  is a top view of the turning bar 
         FIG. 3  shows a section taken along marked in  FIG. 1   
         FIG. 4  is a side view of the tube-forming device 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
       FIG. 1  diagrammatically shows the individual steps for processing a fabric tube to form bags as carried out in the bag-making apparatus  1 . 
     The tube-forming device  13  comprises a spool  3  containing web-shaped material  14 . The web-shaped material  14  is supplied to a tube-forming region  28  in the transport direction x′. Here  28 , the web-shaped material is folded back onto itself in a manner known per se, and the edges are glued or heat-sealed together so that a material tube  2  is formed. Then the tube  2  is provided with a so-called opening in the opening station  5 . For this purpose, the fabric tube is guided around an internal tool that separates the two layers from each other so that the layers are isolated from each other if they have been glued together in any of the production steps of the tube  2 . Only in the case of separate layers can it be ensured that the subsequent production steps are carried out properly. The material layers of the tube  2  that are separated from each other are then again placed on top of each other. 
     In the further course of transport, the tubular material web  2  is supplied to a deflecting device, preferably at least one turning bar  17 . The turning bar  17  is movable in the direction of the double arrow  15 . The material tube  2  is deflected with the help of the turning bar  17  from the original transport direction x′ into the transport direction y, and supplied to a cross cutter  6  that separates the fabric tube into individual tube pieces  16 . 
     Then the tube pieces  16  are transported in a transport direction x extending transversely to their longitudinal axes so that the ends of the tube pieces can be reached laterally by the related processing stations for the purpose of molding the bottoms. 
     The transport direction x′ of the tubular material  2  and the transport direction x of the tube piece  16  extend parallel to each other. 
     The parallel course of the transport direction x′ of the tubular material and the transport direction x of the tube piece also enables the tube-forming device to be arranged so as to extend parallel to the processing stations. This enables a very compact and space-saving design of the bag-producing apparatus. Likewise, the parallelism of the directions of movement x′ and x enables the tube-forming device and the individual processing stations to be set up directly one behind the other and thus a long but slender bag-production line to be achieved. 
     In the subsequent station, the bottom-opening station  8 , both ends of every tube piece are opened and the so-called bottom squares are placed. In the subsequent valve station  9 , a valve is fitted and attached to one of the two open ends. The open bottoms are now closed in the bottom-closing station  10 , two tabs being placed on top of each other and joined together permanently, for example, by means of a heat-sealing process. The application of a bottom patch to the bottom of each bag in the bottom patch station  11  marks the conclusion of the actual bag-making process. Furthermore, the bottom patches can likewise be welded onto the bottoms of the bags. The finished bags are then placed on the stack  12  and removed from here in a manner not described in detail. 
       FIG. 2  is a top view of the turning bar  17 . The turning bar can be mounted for rotation on a holding frame  18  by means of a holder  24 . In the exemplary embodiment shown here, the holding frame  18  is located in a plane that extends parallel to the direction of movement of the tubular material  2 . Slides  20 ,  27  that engage in rails  19  ( FIG. 3 ) are mounted below the holding frame  18 . The holding frame  18  can be moved on the rails  19  with the help of the slides  20 ,  27 . The slide  27  is extended in the z direction. At the bottom end of the extended slide  27  there is a spindle nut inserted, in which a spindle  21  engages. The spindle  21  is rotatable with the help of the motor  23 . As a result of a rotation of the spindle  21  that engages in the spindle nut of the extended slide  27 , the holding frame—and thus also the turning bar  17  mounted for rotation thereon—can be moved in the x′ and −x′ direction. As a result of the movability of the turning bar in a direction (in the x′ and −x′ direction) extending parallel to the direction of movement of the tubular material  2 , the position of the edges of variably broad material tubes can be adjusted to suit the cross cutter or the separating device  6 . 
     The spindle motor  23  is connected to a control device  25  by means of a suitable data line  26 . The width dimensions of the material tubes to be processed can be stored in the control device. A manual input of these width dimensions is also possible. During a job change, the control device  25  controls the spindle motor  23  based on the width dimensions of the tubular material in such a way that the turning bar  17  is moved in the x′ direction until the position of the edges of the tubular material is adjusted to suit the cross cutter or the separating device  6 . 
       FIG. 4  is a side-view of a tube-forming device  13 . The web-shaped material  14  is unwound from a spool  3  and supplied to a tube-forming region  28 , which is not described in more detail and in which  28  the web-shaped material  14  is processed to form tubular material  2 . Then the tubular material travels by means of guide rollers  22  to the turning bar  17 . Alternatively, web-shaped material can also be wound up on a spool  4  in the so-called off-line mode. As mentioned above, the material tube  2  is deflected with the help of the turning bar  17  from the original transport direction x′ to the transport direction y and supplied to a cross cutter  6  that separates the fabric tube into individual tube pieces  16 . With reference to  FIG. 4 , it is apparent that the turning bar is located in a plane above the cross-cutter. The separating device or the cross cutter  6  can also be supplied with tubular material from a separate material spool  29 . The bag-making apparatus can be operated in two modes. In the so-called in-line mode, the cross cutter  6  is directly supplied with web-shaped material by the tube-forming device  13 —by means of the turning bar  17 . In the so-called off-line mode, the cross cutter is supplied with tubular material by a separate spool  29 . The tubular material can be produced beforehand by the tube-forming device  13  and wound up into a spool  4 . In this case, the spool  4  would then be brought into the position of the spool  29  for producing the bags. 
     Below the guided rollers  22  a passageway  7  is located, which  7  can be traversed by the operating personnel. The operating personnel of the bag-making apparatus can thus access both sides of the machine without having to move around the complete machine. This feature is particularly advantageous since the overall machine length is increased as a result of the tube-forming device  13  and the individual tube piece-processing stations being placed one behind the other. The position of the passageway directly next to the separating device or the cross cutter  6  is advantageous since the operator can thus reach the cross cutter  6  more easily and eliminate any cases of material compression, for example. Furthermore, both spools  4  and  29  of tubular material can be accessed by the operator from here. This feature is advantageous both when errors occur as well as when changing a spool of material. 
     The invention being thus described, it will be apparent that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be recognized by one skilled in the art are intended to be included within the scope of the following claims. 
     
       
         
           
               
             
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1 
                 Bag-making apparatus 
               
               
                 2 
                 Tubular material 
               
               
                 3 
                 Spool 
               
               
                 4 
                 Spool comprising tubular material 
               
               
                 5 
                 Opening station 
               
               
                 6 
                 Tube-separating device 
               
               
                 7 
                 Passageway 
               
               
                 8 
                 Bottom-opening station 
               
               
                 9 
                 Valve patch station 
               
               
                 10 
                 Bottom-closing station 
               
               
                 11 
                 Bottom-patch station 
               
               
                 12 
                 Bag stack 
               
               
                 13 
                 Tube-forming device 
               
               
                 14 
                 Web-shaped material 
               
               
                 15 
                 Double arrow 
               
               
                 16 
                 Tube piece 
               
               
                 17 
                 Turning bar 
               
               
                 18 
                 Holding frame 
               
               
                 19 
                 Rails 
               
               
                 20 
                 Slide 
               
               
                 21 
                 Spindle 
               
               
                 22 
                 Guide rollers 
               
               
                 23 
                 Spindle motor 
               
               
                 24 
                 Holder 
               
               
                 25 
                 Control device 
               
               
                 26 
                 Data line 
               
               
                 27 
                 Slide 
               
               
                 28 
                 Tube-forming region 
               
               
                 29 
                 Spool comprising tubular material 
               
               
                 X′ 
                 Transport direction 
               
               
                 X 
                 Transport direction