Abstract:
A device for filling stand-alone flat-bottom bags with opposing side edges and a bottom, in particular filling them with liquid including a filling carousel which can rotate about a vertical axis and which has a plurality of holders for one bag each provided on its circumference. The filling carousel has a bag feeding station, a bag opening station, a filling station and a removal station as well as a sealing station. To optimize the filling device and in particular to achieve a higher throughput, a magazine for prefabricated bags and a feeding carousel for the bags is provided in the bag feeding station, containing a plurality of holding devices for one bag each whereby the holding devices can be driven to rotate about a common axis in order to remove each bag individually from the magazine and transfer it continuously to a holder of the filling carousel.

Description:
FIELD OF THE INVENTION 
   This invention relates to a device for filling stand-alone flat-bottom bags of the type described in the definition of the species of claim  1   
   BACKGROUND OF THE INVENTION 
   Such a device is known from European Patent 576 058 B1. The known device includes a filling carousel which revolves continuously and is charged directly by a bag shaping machine. The bag shaping machine processes film material from a roll to form a bag strand, then it cuts this bag strand into individual bags and transfers the individual bags to a synchronizing device which then transfers them to the continuously revolving filling carousel. Although it is mentioned in said publication that prefabricated bags from a magazine can also be used, the synchronizing device must be retained. The type and design of the synchronizing device is not described, but the description does indicate that evidently linearly movable arms are used. Nor does it describe how the bags are held on the filling carousel. The bags are opened by means of suction cups on the filling carousel and then are filled. Thereafter, the filled bags while still open are transferred to an intermediate wheel from which they subsequently go to a sealing device in the form of a sealing carousel. Although this publication cites the related art as indicating that efficiency is improved with the known device, the known device still has weaknesses, however. One of these weaknesses is the synchronizing device which fills the bags on the filling carousel. The second weakness is the intermediate wheel, which transports the open filled bag, the speed of this transport being limited to ensure that the contents of the bag, in particular when filled with fluid, do not overflow out of the bag. 
   A great variety of such bag filling machines are known in the related art. U.S. Pat. No. 3,323,280, for example, discloses a filling carousel for filling bags with granules. The bags are prefabricated and supplied in a bag magazine from which they are transferred in a linear movement to the filling carousel. In the filling carousel the bags are gripped by a clamping gripper on each of two opposing side seams; the clamping grippers can be moved in relation to one another to open the bag. This movement of the clamping grippers is relatively complicated to perform. Before closing the opening, which is done by sewing in this case, the bags are rotated, which in turn must be accomplished by a complex superimposed movement of the clamping grippers. 
   U.S. Pat. No. 4,580,473 describes a bag filling device which uses a continuous conveyor that conveys the bags, which are clamped onto a continuous conveyor belt, through the different stations. In conveyance, the bag is clamped to only one of these side seams with the help of a clamping gripper. However, the clamped side seam is the forward side seam, which in turn has the disadvantage that both side walls of the bag are no longer available for opening and on the other hand the throughput of bags is greatly reduced because now the bags have their largest dimensions pointing in the direction of conveyance. 
   SUMMARY OF THE INVENTION 
   Thus the object of this invention is to improve upon a device of the type mentioned above which will increase its efficiency. 
   With the design according to this invention, a considerable optimization of the filling device is achieved because the bags can be charged to the filling carousel continuously and nevertheless they are charged from a magazine of prefabricated bags. Neither the fabrication of the bags nor their being made available in cycles by means of the required severing cut thus forms a limit for the operating speed of the filling carousel. 
   In addition, one of the embodiments is also of particular advantage; when taken alone, i.e., without the charging carousel, this leads to a significant increase in operating speed of the bags because now the charging of the bags can take place in a very simple manner because no second gripping device stands in the way and the throughput, i.e., the number of bags that can be accommodated on the filling carousel, is optimized. 
   In addition, due to the fact that the bags are clamped on only one side, it is also possible to integrate the suction gripper for opening the bag into the holder for the bag. The additional supporting area made available its mobility, and the possibility of centering permit further optimization of the holding of the bags on the filling carousel and in particular a better adaptation to subsequent processing steps. 
   This object is also achieved, optionally only by this feature, by the sealing carousel because is it capable of transferring the bags directly from the filling carousel, i.e., without an intermediate wheel. 
   With the present invention, the sealing device of the bag sealing carousel can at the same time assume conveyance functions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Advantageous embodiments of this invention are illustrated in greater detail below on the basis of the drawings, which show: 
       FIG. 1  a schematic diagram of an inventive device as seen from above; 
       FIG. 2  the device according to  FIG. 1  in a perspective side view; 
       FIG. 3  a first design principle in a first mechanism of operation of the bag charging station, as seen from above; 
       FIG. 4  the design principle of the bag charging station according to  FIG. 3  in a second mode of operation; 
       FIG. 5  another design principle of the bag charging station, as seen from above; 
       FIG. 6  a mount of the filling carousel when gripping the bag, as seen from above; 
       FIG. 7  a mount of the filling carousel in opening the bag, as seen from above; 
       FIG. 8  a side view of the mount of the filling carousel, as seen in the direction of movement; 
       FIG. 9  a side view of a mount of the filling carousel as seen in the radial direction; 
       FIG. 10  a perspective diagram of a detail of a filling carousel; 
       FIG. 11  a perspective diagram of another detail of the filling carousel; 
       FIG. 12  a perspective diagram of a detail of the sealing carousel; 
       FIG. 13  a perspective diagram of the sealing jaws of the sealing carousel; and 
       FIG. 14  a schematic diagram of a modified device according to  FIG. 1 , as seen from above. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2  show schematic diagrams of a device  1  for filling stand-alone flat-bottom bags  2 . Stand-alone flat-bottom bags are widely used for packaging, and are used among other things for packaging individual portions of liquids, in particular beverages. Each stand-alone flat-bottom bag  2  (see also  FIGS. 6 through 9 ) consists of two side walls  3 ,  4  made of a flexible film material joined together on their long sides by welds  2   a ,  2   b  and on their short sides by an inserted or folded stand-alone bottom  5 . The side opposite the stand-alone bottom  5  has a filling opening  6  which is also sealed after the container has been filled. 
   The bags  2  are prefabricated, i.e., they are provided with side seams  2   a ,  2   b  and stand-alone bottoms  5  but with the filling opening  6  still open and a stock of bags is kept in a magazine  7 . The bags  2  are removed individually from the magazine  7  at a bag feeding station by means of a feeding carousel  8  which is driven to rotate about a vertical axis  8 ′ and they are transferred continuously to a filling carousel  9  which is also driven to rotate about a vertical axis  9 ′ which preferably runs parallel to the axis  8 ′, so that their rotation is in synchronization with the feeding carousel  8  and in the direction of the arrow I. On the circumference of the filling carousel  9 , a plurality of holders  10  are provided at uniform intervals, shown here only schematically and with the first and last holder for each process step. The filling carousel  9  carries the bags  2  that are held in the holders  10  through an opening station B, where the filling opening  6  is opened by spreading the walls  3 ,  4  of the bag  2 . The opened bag  2  then goes into a filling station C, where it is filled with the product, preferably a beverage. This is followed by a station D where the bag is rotated 90° about its vertical axis in preparation for removing the bag from the filling carousel  9  and sealing its upper opening  6  in the sealing station E. The sealing station E has a sealing carousel  11 , which is driven to rotate about an axis  11 ′ running parallel to the axes  8 ′ and  9 ′, so that rotation is in the direction of the arrow II and in synchronization with that of the filling carousel  9 , and the filled and sealed bags are transferred to a further conveyor  12 , which is indicated only schematically here. 
   The individual stations are described in detail below. 
     FIG. 3  shows a schematic diagram of a first exemplary embodiment of a feeding station A. The feeding station A contains the magazine  7  in which the bags are stacked upright and individually one after the other. The magazine  7  extends essentially tangentially to the filling carousel  9  and is arranged with its feed opening  7   a  tangentially to the feeding carousel  8 . The feeding carousel  8  which can be driven continuously is provided with a plurality of holding devices on its circumference, designed as suction cups  13  in the exemplary embodiment shown here. The suction cups  13  are linked to the rotation of the feeding carousel  8  by a suitable gear  14  (planetary gears having gear wheels are shown here) in such a way that the bags are transferred radially without delay to the filling carousel  9 , whereby in the arrangement of the magazine  7 , the feeding carousel  8  and the filling carousel  9  shown here, the orientation of the suction cups  13  remains constant at least during their movement from the feed opening  7   a  to the holders  10  of the filling carousel  9 . In the exemplary embodiment shown here, the suction cups  13  are oriented essentially perpendicular to the front bag  2  in the discharge opening  7   a  and they maintain this orientation. In the exemplary embodiment depicted here, the feeding carousel  8  rotates in the clockwise direction III while the feeding carousel  9  rotates counterclockwise in the direction of rotation I shown in  FIG. 1 . The suction cups  13  are controlled so that they apply suction to the front bag  2  in each case as they pass by the discharge opening  7   a  of the magazine  7 , conveying that bag in the same orientation into the area of the holders  10  of the filling carousel  9 , where they transfer the bag to one holder  10  each. 
   As  FIG. 4  shows, the feeding carousel  8  in  FIG. 3  may also be operated in the opposite direction of rotation IIIa, i.e., counterclockwise, when the filling carousel  9  rotates in the opposite direction of rotation Ia, i.e., clockwise. The mechanism of action is identical, except that in operation according to  FIG. 4 , the bag must be transported over a smaller angular range of the feeding carousel  8 . 
     FIG. 5  shows a modified embodiment of a feeding carousel  8 . In this embodiment, the feeding carousel  8  has a carousel body  15  on which are arranged pivotable arms  16 , which also carry holding devices in the form of suction cups  13 . The arms  16  are controlled so that they are pivotable from an approximately radial position with respect to the axis of rotation  8 ′ into an essentially tangential orientation thereto. The magazine  7  is also arranged tangentially to the filling carousel  9  in this exemplary embodiment, but its discharge opening  7   a  runs essentially radially to the feeding carousel  8 . The arms  16  are controlled in such a way that they are pivoted out of the discharge opening  7   a  of the magazine  7  into their radial position to accommodate the front bag  2  in each case, then they retain this position in clockwise transport of the bags  2  picked up in the direction of rotation III until the transfer of the bags  2  to the holders  10  radially to the filling carousel which is rotating in the counterclockwise direction I and in doing so rotate the bag  2  by 180°. The arms  16  are then in tangential contact with the carousel body  15  so that the distance between the magazine  7  and the feeding carousel  8  need not be too great. 
   In another arrangement with regard to the position and orientation of the magazine, however, another movement pattern of the suction cups may be necessary and may be implemented. 
   On the basis of  FIGS. 6 through 11 , the holding and handling of the bags in the area of the filling carousel  9  are described. 
     FIG. 6  shows a top view of the holder  10  at the moment of transfer of bag  2  from the feeding carousel  8 . The holder  10  contains a clamping gripper  17  which consists of two clamping jaws  17   a  and  17   b  which are movable in relation to one another by means of a suitable control unit  18  (shown here as a knee joint) between an open position in which the bag  2  is released and a clamped position. In the clamped position, the clamping jaws  17   a ,  17   b  grip the inner side edge  2   b  of the bag  2 , which is at the left in the figure and is on the inside radially with respect to the axis of rotation  9 ′ of the filling carousel  9  and they hold the bag  2  in an essentially radial orientation with respect to the filling carousel  9  with the filling opening  6  pointing upward. 
   The holder  10  also has a support surface  19  which is provided on the top side of a ram  20 . The ram  20  can be moved up and down in the direction of the double arrow IV and can be pivoted about its vertical midline  20 ′ in the direction of the double arrow V. The midline  20 ′ runs in its extension through the middle of the bag  2 . A centering device  21  is provided on the support surface  19 ; in the exemplary embodiment shown here, it includes four holding fingers which stand upward and are distributed around the circumference of the bag and are spaced a distance apart, where this distance corresponds to the circumference of the bag in the area of the bottom  5  when the bag is filled, so that the bag  2  when filled is held securely in the centering device  21 . The holding fingers  21   a  extend in height over approximately one-third of the height of the bag. 
   The holder  10  also has an opening device  22  for opening the filling opening  6  which in the exemplary embodiment shown here contains two suction cups  27  which are supplied with a vacuum and are moved by means of holding arms  28 , which are only shown schematically. The suction cups  27  are arranged on both sides of the bag  2  and pull the two side walls  3 ,  4  apart in a known way for opening the filling opening  6 . 
   As shown best in  FIGS. 2 and 10 , the bags  2  are transferred to the clamping grips  17  at the feeding station A while the supporting surface  19  is still in the lowered state. The supporting surface  19  then travels upward and is in contact with the standing bottom  5  of the bag. The opening device  22  is operated and opens the bag. Then the bag is filled through filling connections  29  in a known way, while the bag  2  is moved through the filling station C together with the filling connection  29  assigned to it. 
   Once the filling is concluded, the clamping grip of the clamping gripper  17  is released, as indicated in  FIG. 11 , and the holding force of the opening device  22  is also released, and the ram  20  together with the supporting surfaces  19  travels downward. Depending on the design of the sealing carousel  11 , the rams  20  may rotate until the side seams  2   a ,  2   b  of the bag  2  are oriented tangentially with the filling carousel  9  and/or tangentially with the sealing carousel  11 . In this position the filling opening may be sealed. 
   Sealing of the filling opening  6  is explained in greater detail below with reference to  FIGS. 12 and 13 . The sealing carousel  11  contains a plurality of sealing grippers  30  which are arranged side by side in the circumferential direction and are preferably designed as part of an ultrasonic sealing device. Each sealing gripper  30  includes a movable clamping jaw  31  with a sealing surface  31   a  and the stationary jaw  32  with a sealing surface  32   a . The sealing surfaces  31   a  and  32   a  can be pressed together by the pivoting of the pivotable jaws  31  for clamping the upper area of the bag  2  about the filling opening  6  and can be acted upon ultrasonically so that the two side walls  3 ,  4  are joined together with a seal in the area of the opening  6  and the bag  2  is thus closed. The clamping surfaces  31   a ,  32   a  run tangentially to the sealing carousel and/or to the filling carousel  9 , i.e., in parallel with the orientation of the bag at the sealing station E, so that the sealing grippers  30  can grip the bag well. By lowering the rams  20  with the filled bags  2  resting on them in this station, the sealing grippers  30  can be moved over the bags without colliding with the filling connections, while the bags are still being held by the supporting surface  19  in sealing so that stretching of the heated material of the bag during the sealing operation under the weight of the full bag is prevented. After sealing the ram  20  continues to move downward so that the bag hanging on the sealing gripper  30  is entrained by the movement of the sealing carousel  11 , is completely cooled and is transported to the further conveyor  12  where the grippers  30  are opened so that the bags standing on their standing bottoms can be transported away through the linear conveyor  12  or through any other suitable conveyor. 
   In a modification of the exemplary embodiments described and drawn here, the filling carousel may also be designed with other traditional holders for the bags. The welding station need not necessarily be designed as a carousel and set up separately from the filling carousel but instead it may also be integrated into the filling carousel, for example. 
   According to  FIG. 14 , a stationary welding station E′ may be arranged in the outlet area of the filling carousel  9  in such a way that its sealing molds  40 ,  41  are oriented tangentially with the partial circle of the filling carousel and with the peripheral cap of the upper area of the bags  2 , whereby the edges which are initially still open at the filling opening  6  of a bag pass through the gap pointing tangentially in the peripheral direction between the stationary sealing molds  40 , 41  and meanwhile are connected with a liquid-tight seal continuously along the peripheral direction due to the influence of the ultrasonic treatment. The stationary ultrasonic vibrating unit of the welding station E′ includes a sonotrode and a mating mold  41  which is designed as an anvil or a rotating roller, for example, and serves as sealing molds in their interaction. This arrangement is inexpensive on the one hand while on the other hand permitting very high material conveyance speeds which in turn permit continuous operation.