MX2007014395A - Method and device for the production of foil bags - Google Patents

Abstract

The invention relates to a method and a device for producing foil bags comprising V-shaped inserted lateral folds and a reclosing mechanism with a slide in a top filling hole. The inventive method encompasses the following steps:window-shaped blanks (10) which delimit the top end of the subsequently formed lateral folds as well as slide blanks (11) are introduced into a planar sheeting. Reclosing mechanisms (6) that are composed of two superimposed and interconnected profiled strips and a slide are placed on the planar sheeting (2) perpendicular to the direction of the sheeting in such a way that the slides lie inside the slide blanks (11). The reclosing mechanisms (6) are connected to the sheeting only at the ends. The sheeting (2) is then directed through a folding station (7) in which the sheeting is folded and lateral folds are molded thereinto. The reclosing mechanisms (6) are joined to the sheeting by means of a sealing seam while the top end of the lateral folds is incorporated thereinto. The superimposed foil layers are finally joined by means of additional sealing seams so as to obtain a run (16) of bags which comprises bag-shaped sections and from which individual foil bags (17) are cut off.

Description

METHOD AND DEVICE FOR PRODUCING FILM BAGS DESCRIPTION OF THE INVENTION The invention relates to a method and device for producing film bags having V-shaped lateral folds and a closure with a slide in a top filling opening. The closing of the film bags consists of two profiled strips and a slide that engages the profiled strips. One of the profiled strips is connected to one front side of the film bag and the other profiled strip is connected to the other front side of the film bag after it is filled. The film bags that are first laid flat are filled with the product they contain in bag filling devices. The filling is carried out by the upper part of the bag. The product is introduced into an opening that still exists between the closure and a front side of the film bag. After this this opening is closed by a sealed seam. Film bags with the described characteristics are used among other things to pack animal feed. Film bags with the described characteristics are known from DE 202 07 333 Ul. Their manufacture is expensive. Following the production of the bag the closures are applied in an annexed section of the plant. For this purpose it is opened by folding a section of film from the film bag already made in the upper area of the bag, a closure is placed on the roll of film below and joins it. After this it is necessary to fold back the open film section and apply the remaining seal seams. The devices required for the application of closures must carry out several processing steps and require considerable space. There is a need to integrate the application of closures in the usual bag production process avoiding an annexed section of the plant. In light of this situation, the invention has for its object to indicate a method in which the application of the closures is carried out before forming the bag during the continuous advancing movement of a roll of flat film. The object of the invention and the solution to this problem is a method for producing film bags according to claim 1. The method according to the invention comprises the following process steps: a) in a roll of flat film are applied window-shaped prints that limit the upper end of the lateral folds that form later, and slide patterns; b) the closures consisting of two profiled strips superimposed and joined to one another as well as a slide that grips the rims of the profiled strips in a rider manner are placed on the roll of flat film perpendicular to the direction of the roll in a manner that the slides are in the slide patterns, and are joined at the ends with the film roll; c) the roll of film is then guided through a folding station in which the roll of film is folded and front surfaces and lateral folds are formed; d) the closures are joined with a front surface by means of a sealed seam incorporating the upper end of the lateral folds; e) the superposed film layers are joined with additional sealed seams to form a row of bags consisting of bag-shaped sections; f) the film bags are separated from the row of bags. The invention is based on the consideration and application of the closures on the roll of flat film prior to the roll of film passing through a folding station, in which it is folded and the lateral folds are formed. The application of the closures according to the invention can be integrated into the existing bags manufacturing plants, the method according to the invention using the stamping devices and the folding devices already existing in a bag production plant. . Nevertheless, the technical problem must be solved that the seals can be diverted during the transport of the film roll through the installation, especially in the folding devices, since the seals first join with the film roll only at the ends . Between the profiled strips of the closure and the continuous roll of film there must be an opening so that the bags can be filled at the upper end. Only after filling the bag is this opening closed by welding the profiled strip with the front side of the film bag. The described technical problem is solved according to the invention by means of steps a) and b) of the process. According to the invention, slides are applied to the roll of film which are exactly in the position of the slides, and during the movement of the roll through the bag-making device, in particular also during the movement of the roll. on the guide plates of the folding station prevent a deviation of the closures and slides against the direction of movement of the film. It can be said that the slides are fixed so to speak in the associated slide patterns. In the case of the sliding stamps, in the simplest case, round holes whose diameter adapts to the geometry of the slide are treated. According to another embodiment of the method according to the invention, weakening lines perpendicular to the longitudinal direction of the roll are introduced into the flat film roll, which are located at the height of the window-shaped recesses and extend over the width of the roll with the proviso that between the weakening lines and the window-shaped recesses there is always a non-weakened film section from 5 mm to 50 mm in width. In the case of weakening lines, it is, for example, a perforation produced by stamping or a weakening line produced by laser technique. The film roll is guided in the folding station so that the edges of the folding tools are in contact with the non-weakened film areas between the perforation / weakening line and the recesses. The folding of the continuous roll of film to form a continuous roll in the form of a sleeve is carried out using triangular folding sheets, the window-shaped patterns being guided centrally on the triangular sheets. Along the edges of the row of bags it is possible to apply continuous longitudinal sealing seams in the longitudinal direction of the roll. In the longitudinal sealing seams conveniently apply stamped cuts that are connected with the lines of weakening. The bags can be separated from the row of bags in different ways. An embodiment of the method according to the invention provides that the bags are separated from the row of bags by a separation cut, being that between the edge of the cut and the adjacent line of weakness remains a section shaped strip that covers the closure . The strip can be used as an originality closure if the double-layer strip is sealed at its upper edge with a transverse sealing seam after the film bag is filled. In the first use of the film bag it is necessary to separate the upper strip with what the closure is exposed on the upper edge of the film bag. If the sealing seam of the waste strip is undamaged, then it is ensured that the film bag was not previously opened.

Within the framework of the method according to the invention it is also possible to separate the bags from the row of bags along the lines of weakening by applying, for example, by a twisting of the roll a pulling force in the longitudinal direction of the roll on the bag to be separated. The bags are torn from the row of bags along the weakening line. At the end of the bottom side of the torn film bags is a residual piece that can be used as a material to form and seal the bottom of the bag. Another embodiment of the method according to the invention provides that the bags are separated by a separation cut of the row of bags and that between the cutting field and the closing remains a strip-shaped section consisting of two layers of film, which covers the closure, and the layers of film covering the closure are separated from the bag with a cutting knife to expose the slide of the closure. In this embodiment of the method they are separated by bending and cutting the projecting film sections after folding and sealing the bag. By this, smooth film edges are produced which are not biased in the longitudinal sealing seams. Another object of the invention is a device for executing the method, comprising a unwinding station for pulling a continuous roll of flat film from a film reel, a stamping device with stamping tools that produce in the continuous roll of flat film window-shaped prints which limit the upper end of lateral folds, a feeding device for pre-assembled closures consisting of in each case two profiled strips superimposed and connected to each other as well as a slide which grips the closing edges in a rider manner of the profiled strips, a folding station with folding devices for folding into two layers of the film roll and for inserting V-shaped side pleats, sealing stations for transverse sealing and longitudinal sealing of the continuous roll of folded material , and a station to separate the film bags from the continuous roll of mat The printing device arranged upstream of the folding station comprises additional embossing tools which introduce slides in the roll of flat film, and wherein a device is provided between the embossing device and the folding station. which places the transverse fasteners in the longitudinal direction of the roll in such a manner on the flat film roll that the sliders of the fasteners remain in the associated slide patterns. The invention is explained below by means of a drawing that only represents one embodiment. They schematically show: Figure 1 the block diagram of an installation for producing film bags having lateral folds inserted in a V shape and a closure with a slide in a top filling opening, Figure 2 a section of a roll of flat film with Patterns applied in accordance with the invention before the roll of film is fed to a folding station of the installation shown in Figure 1, Figures 3a to 3c, products of the method that can be produced with the installation shown in Figure 1. The installation depicted in FIG. 1 comprises an unwinding station 1 for pulling a continuous roll 2 of film from a film reel 3, a stamping device 4, a feed device 5 for pre-assembled closures 6, a station 7 of folding with folding devices to fold in two layers the continuous roll 2 of film and to insert lateral folds with fo V, sealing stations 8 for the transverse sealing and longitudinal sealing of the continuous roll of folded material as well as a station 9 for separating film bags from the continuous roll of material. In the stamping device 4 are applied to the continuous roll 2 of flat film patterned 10 in the shape of a window, which delimit the upper end of the lateral folds that will be formed later, as well as slide patterns 11 (figure 2). The fasteners 6 that are fed to the continuous roll of material consist of two profiled strips 12 superimposed and connected to one another and of a slide 13 that grips the rims of the profiled strips in a rider manner. The pre-assembled closures 6 are placed on the continuous roll 2 of flat film so that the slides 13 remain in the slider prints 11 and then are connected at the ends 14 with the continuous roll 2 of film. Figure 2 shows the continuous roll of film with the fasteners 6 placed before the continuous roll of film is fed to the folding station 7. In the folding station 7 the continuous film roll is bent to form a continuous roll of two-ply material and the lateral folds are inserted. In the subsequent sealing stations 8 the fasteners 6 are connected to a front surface of the bag by a sealed seam incorporating the upper end of the side folds, and the overlaid film layers are connected by additional sealed seams 15 to form a row 16 of bags consisting of bag-shaped sections. In a last station 9 the film bags 17 are separated from the row 16 of bags. The product of the method is shown in Figure 3a. The film bag 17 shown in Figure 3a comprises two front sides, side folds 18 inserted in a V-shape between the front sides and a closure 6 in an upper opening of the bag. The closure 6 consists of two profiled strips 12 and a slider 13 which engages the profiled strips. One of the profiled strips 12 is connected to a front side of the bag. The other profiled strip connects to the other front side after filling the bag. The superimposed film layers of the bag are joined by transverse and longitudinal sealed seams 15 along the bottom and along the edges of the side folds 18, with the longitudinal sealing seams 19 extending along the lengths of the edges. lateral folds 18 extend from the bottom to the upper edge of the bag. The closure 6, including its slide 13, is located within the bag spaced from the upper edge of the bag. A front side of the bag has a slide pattern 11 adapted to the dimension of the slide 13, in which the slide 13 is placed before the first use of the bag. The front sides of the film bag 17 have at the upper end of the bag a strip-shaped section 20 covering the tear-off closure along a weakening line 21 which is located approximately at the height of the sliding or under the slide. In the exemplary embodiment, the weakening line 21 consists of a perforation produced by stamping. The weakening line can also be produced by laser technique if a nice optical separation edge is desired. Patching lines 22 are connected to the ends of the perforation line 21 which extend through the longitudinal sealing seams 19 to the outer edges of the bag. The lateral folds 18 end below the line 21 of perforations. The strip-shaped section 20 is separated from the film bag 17 along the perforation line 21 and the stamping lines 22 added. With this the closure 6 is exposed. The line 21 of perforations is made in the continuous roll of flat material and is shown in Figure 2. From Figure 2 it is clear that the line 21 of perforations extends over the width of the continuous roll with the proviso that between the perforation and the window-shaped recesses 10 there is in each case a section 23 of non-perforated film from 5 mm to 50 mm in width. To make the film bags 7 shown in Figure 3a the bags are separated from the row 16 of bags by a separation cut.there remains a strip-shaped section covering the closure between the cutting edge and the adjacent perforation line 21. The film bags shown in Figure 3a are used, for example, to pack animal feed. The filling is done through the upper part of the bag. The packaged product is inserted into an opening that still exists between the closure and a front side of the film bag. After this this opening is closed by a sealed seam. As an original closure, the upper edge of the strip-shaped section that is torn off when using the film bag for the first time is additionally sealed. The sealing is carried out with a sealing seam 24 connecting the film layers. In the bag filling installation the bottom of the film bag is folded to obtain a base to stop the bag. In the embodiment of the film bag shown in Figure 3b the slide 13 of the reconstituted film bag is exposed. This is achieved in the installation depicted in Figure 1 by separating the bags from the row of bags along the line 21 of perforations. At the end of the bottom there is a residual piece 25 containing the slide print 11 and that after filling the bag is folded together with the bottom fold. It is not necessarily necessary to manufacture the perforated line 21. To produce the film bag shown in Figure 3c the bags are separated from the row 16 of bags by a separation cut. When this occurs, between the cutting edge and the closure 6 there remains a strip-shaped section consisting of two layers of film covering the closure 6. The layers of film covering the closure are separated by bending and cutting in the last processing station. By this the upper film edges of the bag are smooth and do not have points of release perforations.

Claims (7)

1. CLAIMS 1. Method for producing film bags comprising lateral folds inserted in a V-shape and a closure with a slide in a top opening, characterized in that it comprises the following steps of the method: a) in a roll of flat film, prints are applied in window form that limit the upper end of the lateral folds that form later, and slide patterns; b) the closures consisting of two profiled strips superimposed and joined to one another as well as a slide that grips the rims of the profiled strips in a rider manner are placed on the roll of flat film perpendicular to the direction of the roll in a manner that the slides are in the slide patterns, and are joined at the ends with the film roll; c) the roll of film is then guided through a folding station in which the roll of film is folded and front surfaces and lateral folds are formed; d) the closures are joined with a front surface by means of a sealed seam incorporating the upper end of the lateral folds; e) the superposed film layers are joined with additional sealed seams to form a row of bags consisting of bag-shaped sections; f) the film bags are separated from the row of bags.
2. 2. Method of compliance with the claim 1, characterized in that in a continuous roll of film weakening lines are applied perpendicular to the longitudinal direction of the continuous roll, which are located at the height of the window-shaped recesses and extend over the width of the continuous roll with the condition In each case there is a non-weakened film section from 5 mm to 50 mm wide between the weakening lines and the window-shaped recesses.
3. 3. Method of compliance with the claim 2, characterized in that continuous longitudinal sealing seams are applied along the edges of the row of bags in the longitudinal direction of the continuous roll and that stamped cuts added to the lines of weakness are applied to the longitudinal sealing seams.
4. Method according to claim 2 or 3, characterized in that the bags are separated from the row of bags by a separation cut, and between the cutting edge and the adjacent weakening line there is a strip-shaped section covering the closing.
5. Method according to claim 2 or 3, characterized in that the bags are separated from the row of bags along the weakening lines.
6. 6. Method according to claim 1, characterized in that the bags are separated from the row of bags by a separation cut, and between the separation cut and the closure is a section in the form of a strip consisting of two layers of film which covers the closure, and because the layers of film covering the closure are separated from the bag with a cutting knife to expose the slide of the closure. Device for carrying out the method according to any of claims 1 to 6, characterized in that it comprises - a unwinding station for pulling a continuous roll of flat film from a film reel, - a stamping device with tools for stamping produced in the flat film roll window-shaped prints that limit the upper end of lateral folds, - a feeding device for pre-assembled closures consisting of in each case two profiled strips superimposed and connected to each other as well as a slide which grasps the closing edges of the profiled strips in a jockey manner, - a folding station with folding devices for folding into two layers of the film roll and for inserting V-shaped lateral folds, sealing stations for sealing cross section and the longitudinal sealing of the continuous roll of folded material, and - a station for separating the film bags from the continuous roll of material, with the stamping device disposed upstream of the folding station comprising additional stamping tools which introduce slides in the flat film roll, and a device is provided between the embossing device and the folding station which places the transverse fasteners in the longitudinal direction of the roll in such a manner on the flat film roll that the sliders of the fasteners remain in the associated slide patterns. SUMMARY The invention relates to a method and device for producing film bags having V-shaped lateral folds and a closing mechanism with a slide in a top filling opening. The inventive method comprises the following process steps: in a roll of flat film, patterns are produced in the shape of a window delimiting the upper end of the lateral and patterned folds (11) of slides. After this the closing mechanisms (6) composed of two superimposed and interconnected profiled strips and a slide are placed on the film roll (2), perpendicular to the direction of the film, so that the slides are inside the prints (11) of slide. The closing mechanisms (6) are only connected at their ends to the film. Next, the film roll (2) is guided through a folding station (7) in which the film is folded and the lateral folds are formed therein. The closing mechanisms (6) are attached to the roll of film by a sealed seam incorporating the upper end of the side folds. Finally, the superimposed film layers are joined by additional sealed seams so that a row (6) of bags consisting of bag-shaped sections is obtained, from which separate film bags (17) are separated,