Abstract:
A method includes flattening a first end portion and a second end portion of a first sealed end of a container. The container is filled with food product and includes a second sealed end positioned opposite the first sealed end. The method further includes folding the first end portion and the second end portion towards a middle portion of the first sealed end of the container that is located between the first and second end portions of the first sealed end of the container.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application of U.S. patent application Ser. No. 13/511,337 filed on Jun. 15, 2012, which is a U.S. National Stage application based on International Patent Application No. PCT/SE2010/000273 filed on Nov. 12, 2010, which claims priority to Swedish Patent Application No. 0901479-6 filed on Nov. 24, 2009, the entire content of all three of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention generally relates to the field of packaging technology. More particularly, the invention relates to a device for facilitating folding of a container, an apparatus comprising the device, and a method for folding the container. 
       BACKGROUND DISCUSSION 
     Background of the Invention 
       [0003]    An apparatus for packaging pourable food in containers comprise a number of steps. In short, such an apparatus may comprise the steps of forming a tube of a web of packaging material, filling said tube with the pourable food, forming containers from the tube by transversally sealing and cutting the tube, and folding the containers to their final form. Further, the folding step can be divided into a number of sub-steps. For example, during a first folding sub-step performed in association to the sealing and cutting step, a section of the containers being sealed may be formed to have a rectangular cross-section. In later folding sub-steps, the container may be folded in such a way that a rectangular base is achieved, e.g. by folding the outer ends of the sealing end into the middle of the sealing end. 
         [0004]    In order to reduce the risk of having leaking containers it is important that the folding is made correctly, since an improper folding can create tensions in the containers, which can result in leaking containers. This is especially important if the packaging material comprises several layers, such as a carton layer, plastic layers and an aluminum foil. 
         [0005]    In order to facilitate the folding and thus reduce the risk of improper folding, packaging material having creasing lines may be used. However, although packaging material provided with creasing lines is used, there is still a risk that the folding is made improperly. 
       SUMMARY 
       [0006]    In view of the above, an objective of the invention is to solve or at least reduce the problems discussed above. In particular, an objective is to improve a filling machine in such a way that the number of improperly folded containers is reduced. 
         [0007]    The general idea is to flatten a first and a second end portion of a sealed end of a container by two flattening elements such that later folding of the first and second end portion towards a middle portion, placed between the first and second end portion, is facilitated. 
         [0008]    According to a first aspect a device is provided. The device comprises a first flattening element and a second flattening element arranged to flatten a first end portion and a second end portion of a sealed end of a container, respectively, such that folding of the first end portion and the second end portion towards a middle portion placed between the first end portion and the second end portion is facilitated. 
         [0009]    The first flattening element and the second flattening element may be a first flattening wheel and a second flattening wheel, respectively. 
         [0010]    The device may further comprise a conveyor belt, placed between the first flattening element and the second flattening element, arranged to hold the middle section of the sealed end down folded. 
         [0011]    Further, a speed of the conveyor belt may be equal to a speed of the first flattening element and the second flattening element. 
         [0012]    An advantage of having the same speed for the flattening elements and the conveyor belt is that less shear stress is generated in the container. 
         [0013]    Moreover, the conveyor belt, the first flattening element and the second flattening element may have a common driving shaft. 
         [0014]    The first flattening element and the second flattening element may have a rubber coating. Alternatively, the first flattening element and the second flattening element may be made of rubber. 
         [0015]    According to a second aspect an apparatus is provided. The apparatus comprises a conveyor for transporting containers in an upright position, a plate adapted to direct a sealed end of said container into a down folded position during transportation of said container by said conveyor, and a device according to the first aspect. 
         [0016]    A speed of the first flattening element and the second flattening element of the device may be equal to a speed of the conveyor. 
         [0017]    The apparatus may further comprise rails adapted to direct a first end portion and a second end portion of the sealed end such that the first end portion and the second end portion are bended substantially 90 degrees in relation to a middle portion of the sealed end during transportation of the container by the conveyor. 
         [0018]    The conveyor belt of the device may be arranged to hold the middle portion of the sealed end during the first end portion and the second end portion are bended substantially 90 degrees in relation to the middle portion by the rails. 
         [0019]    According to a third aspect a method for folding a container is provided. The method comprises flattening a first end portion and a second end portion of a sealed end of said container, and folding the first end portion and the second end portion towards a middle portion of the sealed end. 
         [0020]    The middle portion may be held down folded by a conveyor belt during the step of flattening the first end portion and the second end portion of the sealed end of the container. 
         [0021]    Further, the step of folding the first end portion and the second end portion towards the middle portion of the sealed end may comprise the sub-step bending the first end portion and the second end portion substantially 90 degrees in relation to the middle portion while the middle portion is held in position by the conveyor belt. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, wherein: 
           [0023]      FIG. 1 a -1 d    illustrate a container during four different folding sub-steps from a first side view, a second side view and seen from above. 
           [0024]      FIG. 2  illustrates the final form of the container. 
           [0025]      FIG. 3  illustrates an apparatus for folding containers. 
           [0026]      FIG. 4  illustrates the apparatus in further detail. 
           [0027]      FIG. 5  illustrates a side view of the apparatus. 
           [0028]      FIG. 6  illustrates a top view of the apparatus. 
           [0029]      FIG. 7  illustrates an improperly folded container. 
           [0030]      FIG. 8  illustrates a device of the apparatus in further detail. 
           [0031]      FIG. 9  illustrates a cross-section of the device. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    After the steps of filling, sealing and cutting have been performed in a filling machine, a container  100  having a first sealing end  102  and a second sealing end  104  can be obtained, as illustrated in  FIG. 1 a   . During the filling step, a section  106  of the container  100  may be formed to have a rectangular cross-section. 
         [0033]    Starting from the section  106 , the container  100  may be folded in a number of sub-steps such that a rectangular base is achieved. In a first folding sub-step the first sealing end  102  is down folded and pushed towards the section  106 , thereby achieving a substantially flat surface, as illustrated in  FIG. 1 b   . The surface may be divided in a first end portion  108   a , a second end portion  108   b  and a middle portion  110 . The first end portion  108   a  and the second end portion  108   b  can be substantially triangular and the middle portion  110  can be substantially rectangular with the same size as the rectangular cross-section of the section  106 . 
         [0034]    Then, in a pre-folding step, the first end portion  108   a  and the second end portion  108   b  can be flattened by flattening elements. An advantage of flattening the end portions  108   a ,  108   b  is that folding of the outer ends  108   a ,  108   b  towards the middle portion  110  is facilitated, and thereby that the risk of having folding lines not placed in the intersections between the outer ends and the middle portion is reduced. 
         [0035]    In a next folding sub-step, the first end portion  108   a  and the second end portion  108   b  can be folded such that the first sealing end  102  is bended about 90 degrees in an intersection between the first end portion  108   a  and the middle portion  110 , and in an intersection between the second end portion  108   b  and the middle portion  110 , as illustrated in  FIG. 1   c.    
         [0036]    Finally, in the last folding sub-step, the first end portion  108   a  and the second end portion  108   b  can be folded inwardly towards the middle portion  110 , thereby forming a substantially rectangular base of the container  100 , also referred to as a bottom. As illustrated in  FIG. 1 d   , the first sealing end  102  can be bended about 180 degrees in the intersection between the first end portion  108   a  and the middle portion  110 , and in the intersection between the second end portion  108   b  and the middle portion  110 . By pressing the outer parts of the end portions  108   a ,  108   b  towards the middle portion  110  a more stable bottom may be achieved such that when the container  100  is standing with the bottom down, as illustrated in  FIG. 2 , the inwardly folded first and second end portions  108   a ,  108   b  as well as the middle portion  110  are in contact with the underlaying surface. However, in order to illustrate the folding of the container  100 , no account has been taken to that the end portions  108   a ,  108   b  are pressed towards the middle portion  110  in  FIG. 1 c    and  FIG. 1   d.    
         [0037]      FIG. 3  illustrates an apparatus  200  for folding containers  100 , as illustrated in  FIG. 1 a   , into containers having a rectangular base as illustrated in  FIG. 1 d    and  FIG. 2 . 
         [0038]    The container  100  can be fed from the filling machine to the apparatus  200  via a conveyor belt. When reaching the apparatus  200  the container  100  can be introduced with the second sealing end  104  first into a wedge-shaped pocket formed between two consecutive carriers of a conveyor  202  running in a conveyor direction CD. During transportation the first sealing end  102  can be down folded by a plate  204 . The plate  204  can be mounted such that a distance between the plate  204  and the conveyor  202  diminishes successively as the container  100  is transported along the conveyor  202 . An effect of this is that the containers can successively be transformed from the shape illustrated in  FIG. 1 a    to a shape illustrated in  FIG. 1   b.    
         [0039]    Next, the container can reach a first flattening wheel  302   a  arranged to flatten the first end portion  108   a  of the first sealing end  102  and a second flattening wheel  302   b  arranged to flatten the second end portion  108   b  of the first sealing end  102 . The flattening wheels  302   a  and  302   b  are arranged rotatably around a horizontal axis perpendicular to the conveyor direction CD. In this way the flattening wheels  302   a  and  302   b  may apply a higher downward pressure, since their rotational movement follows the conveyor direction CD, diminishing risk of interference with the conveyor direction CD at higher pressures. In order to make sure that the first sealing end  102  is kept in position, a conveyor belt  304  placed between the first flattening wheel  302   a  and the second flattening wheel  302   b  can be used. As illustrated in  FIG. 3 , the first flattening wheel  302   a , the second flattening wheel  302   b  and the conveyor belt  304  may rotate around a common rotational axis RA 1 . The conveyor belt  304  may further rotate around a rotational axis RA 2 . 
         [0040]    An advantage of flattening the end portions  108   a ,  108   b  is that if any product, with which the container is filled, is present in the end portions this can be moved to the middle portion  110 , which makes it possible to achieve thinner and more well-defined end portions. Thinner end portions, in turn, provide for that the folding of the end portions towards the middle portion  110  is facilitated. 
         [0041]    Another advantage, if a speed of the first flattening wheel  302   a  and the second flattening wheel  302   b  is equal to a speed of the conveyor  202 , is that the first and second end portions  108   a ,  108   b  may be flattened during transportation without generating unwanted shear stress in the container  100 . 
         [0042]    Next, the end portions  108   a ,  108   b  can be folded upwards 90 degrees, as illustrated  FIG. 1 c   , by rails  206  directing the end portions  108   a ,  108   b  as the containers are transported by the conveyor  202 . In order to control that the folding is made as intended, that is, in the intersection between the end portion  108   a  and the middle portion  110 , and the intersection between the end portion  108   b  and the middle portion  110 , the middle portion  110  can be held in correct position by the conveyor belt  304 . Thus, the outer ends of the conveyor belt  304  provide for that the folding is made as intended. In order to reduce the risk of deformation of the containers, a speed of the conveyor  202  may be equal to a speed of the conveyor belt  304 . 
         [0043]    After the end portions  108   a ,  108   b  have been folded upwards about 90 degrees, heating elements  208  can heat the end portions  108   a ,  108   b  as they are transported by the conveyor  202 , thereby melting a plastic layer of the containers. 
         [0044]    Then, in a final folding sub-step, the end portions  108   a ,  108   b  can be folded inwardly and pressed towards the middle portion  110 . Due to the heating of the end portions  108   a ,  108   b , these attach to the middle portion  110 . As the melted plastic layer is cooled down the end portions  108   a ,  108   b  are permanently attached to the middle portion  110 . Further, by pressing the end portions  108   a ,  108   b  towards the middle portion  110 , a rectangular base can be formed such that when the container is standing with the rectangular base down the container rests on the outer end portions  108   a ,  108   b  and the middle portion  110 . 
         [0045]    The first and second flattening wheels  302   a ,  302   b  may be attached by screws to a first cogwheel of the conveyor belt  304 , as illustrated in  FIG. 4 , thereby making it easy to replace the first and second flattening wheels  302   a ,  302   b.    
         [0046]      FIG. 5  illustrates a side view of the apparatus  200  and  FIG. 6  illustrates a top view of the apparatus  200 . When the end portions  108   a ,  108   b  have been flattened by the flattening wheels  302   a ,  302   b  the rails  206  can fold the end portions  108   a ,  108   b  upwards about 90 degrees. As described above, by holding the middle portion  110  in position by the conveyor belt  304 , the risk of improper folding can be reduced. Further, as illustrated, rails having the function as counter elements may be provided in association to the flattening wheels. 
         [0047]    One type of improper folding of the container is illustrated in  FIG. 7 . Such an improper folding may arise if for instance a fixed plate is used instead of a conveyor belt  304 . More particularly, by having a fixed plate, friction may arise between the container  100  and the fixed plate, thereby holding back the middle portion  110 , but not the outer portions  108   a ,  108   b , thereby giving rise to an improper folding and unwanted stress in the container  100 , and possibly a leaking container. 
         [0048]    In order to drive the first and second flattening wheels  302   a ,  302   b , and the conveyor belt  304 , a driving shaft  306  may be used, as illustrated in  FIG. 8  and  FIG. 9 . The driving shaft  306  may be common to the first and second flattening wheels  302   a ,  302   b  and the conveyor belt  304 . The driving shaft  306  may be connected to an engine (not shown). A device  300  comprising the first and second flattening wheels  302   a ,  302   b , the conveyor belt  304  and the driving shaft  306  may thus form part of the apparatus  200 . 
         [0049]    The first and second flattening wheels  302   a ,  302   b  may be provided with rubber coatings. The rubber coatings may be resistant to hydrogen peroxide, which may be used to sterilise the packaging material. Alternatively, the first and second flattening wheels  302   a ,  302   b  may be made of solid rubber. 
         [0050]    The conveyor belt  304  may also be provided with a rubber coating resistent to hydrogen peroxide. 
         [0051]    Instead of using the first and second flattening wheel  304   a ,  304   b , a first and second flattening conveyor belt may be used. The first and second flattening conveyor belt may be shorter than the conveyor belt  304 , such that the outer ends of the conveyor belt  304  can be used when folding the first and second end portions  108   a ,  108   b  upwards as described above. 
         [0052]    Although the apparatus  200  and the device  300  are described with respect to containers having a rectangular base and an unfolded sealing end as a top, the scope of the invention is generally applicable to containers  100  having a sealed end  102  comprising a first end portion  108   a , a second end portion  108   b  and a middle portion  110 , where the first and second end portions  108   a ,  108   b  are inwardly folded and attached to the middle portion  110 . 
         [0053]    The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.