Abstract:
An apparatus for opening bags lying flat is part of a packaging system having a conveyor system, with receiving cups, located at equal intervals, for the bags. The bags are kept on hand in the form of blanks lying flat in bag magazines and are taken from the bags by means of a bag extracting device. By means of a gripper device, the blanks reach the region of suction plates, which open the blanks and insert them into the receiving cups. The apparatus according to the invention makes high capacity with a relatively simple construction possible.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to an improved apparatus for opening bags lying flat. 
   2. Description of the Prior Art 
   One apparatus of the type with which this invention is concerned is known from Swiss Patent CH 315224. In this known apparatus, one bag lying flat at a time is taken from a bag magazine by means of a suction arm, which is located linearly displaceably and pivotably in a shaft. The bag that is removed is transferred, after a pivoting motion of the arm, to a rotor that has four receiving places for bags. The rotor is rotatable in increments of 90° each in a vertically disposed shaft and firmly holds each bag during its entire conveying travel, or during the entire rotation of the rotor, by means of a gripper device. The grasping of each bag by the gripper device is made possible by two suction devices that engage diametrically opposed sides of the bag. A further suction device for opening the bag is provided in the region of a filling station that makes it possible to introduce a filling tube into the bag. The known apparatus, because of the high number of gripper devices, is relatively complicated in its construction. Moreover, the capacity of the known apparatus is limited by the fact that only one bag at a time can be dispensed to the rotor. 
   OBJECT AND SUMMARY OF THE INVENTION 
   The apparatus according to the invention for opening bags lying flat has the advantage that while having a relatively simple construction, it enables reliable operation at high capacity. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of a preferred embodiment taken in conjunction with the drawings, in which: 
       FIG. 1  is a simplified plan view of a packaging system embodying the invention; 
       FIG. 2  is a plan view of the packaging system of  FIG. 1  in the region of the bag delivery; 
       FIG. 3  is a section taken in the plane III—III of  FIG. 2  in the region of a bag magazine; and 
       FIG. 4  is a section through the system of  FIG. 2  in the region of a bag insertion station. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The apparatus  10  shown in the drawings serves to open bags  1  lying flat, kept on hand in the form of blanks  2 , and to insert these bags  1  into a conveyor system  11  of a packaging system. The conveyor system  11 , designed as an oval rotor, has an endless conveying side  12 . Receiving cups  15 , adapted to the shape and size of bags  1 , are secured replaceably to the conveying side  12  at equal intervals by means of carriers  14 . The receiving cups  15  have a bottom  16 , two side walls  17 ,  18 , and one back wall  19 . The side of the receiving cup  15  diametrically opposite the back wall  19  is open, so that in plan view ( FIG. 1 ), receiving cups  15  that are open toward the outside are created. 
   The receiving cups  15  are advanced incrementally clockwise in the direction of the arrow  13  by means of a drive mechanism, not shown, via the conveying side  12 ; in the exemplary embodiment shown, the conveying increment corresponds to the spacing of two divisions t between two receiving cups  15 . The conveyor path of the conveyor system  11  can be divided into a first region  21 , in which the blanks  2  are furnished; a second region  22 , in which the blanks  2  are inserted as bags  1  into the receiving cups  15  and the bags  1  are simultaneously filled with a product, in particular a pourable product; a third region  23 , in which a product compression is done; a fourth region  24 , in which closure devices, not shown, for closing the bags  1  are located; and a fifth region  25 , in which the filled, closed bags  1  are removed from the receiving cups  15  of the conveyor system  11 . 
   In the first region  21 , extending rectilinearly, two bag magazines  28 ,  29  are located side by side as viewed in the conveying direction of the receiving cups  15 . Each of the two bag magazines  28 ,  29 , which are known per se and identical to one another, has lateral guides  30 ,  31  with retaining lugs  32 ,  33  for restraining the frontmost blank  2  in the bag magazine  28 ,  29 . The blanks  2  are pressed or conveyed, each by means of one conveyor belt  34 ,  35  located in the region of the bottom of the bag magazines  28 ,  29 , toward the retaining lugs  32 ,  33 , so that a blank  2  is always ready there. The bag magazines  28 ,  29  are preferably filled manually; that is, as the fill level drops, additional blanks  2  are introduced by hand into the bag magazine  28 ,  29  between the guides  30 ,  31 , from the side diametrically opposite the retaining lugs  32 ,  33 . 
   A bag extracting device  36  is located on the conveyor system  11  between the bag magazines  28 ,  29  and the receiving cups  15 . The bag extracting device  36  includes two coupled-together suction plates  37 ,  38 , which are movable perpendicular to the conveying direction of the receiving cups  15 , or in other words parallel to the orientation of the bag magazines  28 ,  29 , as indicated by the double arrows  41 ,  42 . Each of the identically embodied suction plates  37 ,  38  is brought into coincidence with the wall  3 , oriented toward it, of a blank  2  and is movable between a withdrawal position and a transfer position. In the withdrawal position, the suction plates  37 ,  38 , are each in contact with one of the blanks  2  in the associated bag magazine  28 ,  29 . Via a vacuum source, not shown, an underpressure is applied to the respective wall  3  of the blank  2 , and this underpressure, upon movement of the suction plates  37 ,  38  into the transfer position that is spaced apart from the bag magazines  28 ,  29 , causes the applicable blank  2  to overcome the resistance of the retaining lugs  32 ,  33  so that it can be pulled out of the bag magazine  28 ,  29 . 
   Upon the transfer of the blanks  2  from the bag magazines  28 ,  29  to the transfer position shown in  FIG. 3 , the bottom  5 , placed flat against the wall  4  of the blank  2  and folded, is repositioned to the horizontal, which is meant to be represented by the arrow  43  in  FIG. 3 , by means of a bottom repositioning slide, not shown. 
   A gripper device  44  is located above the bag extracting device  36 , in the region of the transfer position of the suction plates  37 ,  38 . For each blank  2 , the gripper device  44  has one gripper  45 , which are coupled to one another and each assigned to one of the suction plates  37 ,  38 . As shown in  FIG. 3 , the gripper  45  has two openable and closable prongs  46 ,  47 , which are pivotable about a common shaft  49 . The gripper device  44  and its grippers are movable back and forth between the first region  21  and the second region  22 , that is, parallel to the conveyor path of the receiving cups  15 , in the direction indicated by the double arrow  51 . 
   In the second region  22 , a slide plate  52  ( FIG. 2 ) is located next to the conveyor path of the receiving cups  15 , at the level of the bottom  16  of the receiving cups  15 . Two further suction plates  54 ,  55 , coupled together, are also provided, aligned with the wall  4  of the blanks  2 , and are movable as indicated by the double arrows  56 ,  57 . 
   On the side of the back walls  19  of the receiving cups  15 , facing away from the slide plate  52 , two suction plates  59 ,  60 , embodied in comblike fashion and coupled together and visible in  FIGS. 2 and 4 , are provided, which cooperate with the two suction plates  54 ,  55  and are aligned centrally with the receiving cups  15 , when the receiving cups are in a stopped position in the second region. The two slight protrusions  62  of the suction plates  59 ,  60  are located in coincidence with recesses, not identified by reference numerals, in the back walls  19  of the receiving cups  15 , so that upon a motion of the suction plates  59 ,  60  in the direction of the slide plate  52 , the protrusions  62  can penetrate through the recesses of the receiving cups  15 . Also provided in the second region  22 , above the conveyor system  11 , is a filling device  65 , with two metering tubes  66 ,  67  that can be introduced into the opening cross section of the opened bags  1  (represented by dot-dashed lines in  FIG. 4 ) and are optionally pivotable in the conveying direction  51  of the bags, in order to lengthen the filling time. 
   The apparatus  10  described thus far functions as follows: By means of the suction plates  37 ,  38  of the bag extracting device  36 , one blank  22  is pulled simultaneously out of each of the bag magazines  28 ,  29 . The blanks  2  are transferred, in the transfer position ( FIG. 3 ), to the grippers  45  of the gripper device  44 , and after that, the underpressure at the suction plates  37 ,  38  is switched off. Next, the grippers  45  are moved into the position that is aligned with the suction plates  54 ,  55 . The suction plates  54 ,  55  are then put into contact with the blanks  2 , and an underpressure for holding the blanks  2  is generated. Now the prongs  46 ,  47  of the grippers  45  can be opened and returned to their original position for taking over the blanks  2  that follow. The suction plates  54 ,  55  are now moved into the receiving cups  15 , while simultaneously, through the receiving cups  15 , the suction plates  59 ,  60  are put into contact with the walls  3  facing them of the blanks  2 . By a controlled motion that spreads the respective cooperating suction plates  54 ,  59  and  55 ,  60  apart from one another, these plates act as opening devices for the blanks  2 , so that the metering tubes  66 ,  67  inside the receiving cups  15  plunge into the opening cross sections of the bags  1 , and filling can begin. As soon as the metering tubes  66 ,  67  are located inside the bag openings, the underpressure at the suction plates  54 ,  55 ,  59 ,  60  can be shut off. Finally, the suction plates  54 ,  55 ,  59 ,  60  are moved back into their original position, whereupon the procedures are repeated as described. It is understood that the drive of the conveyor system  11  must be adapted, particularly to the suction plates  54 ,  55 ,  59 ,  60 , such that the introduction of the blanks  2  into the receiving cups  15  is always done while the conveyor system  11  is stopped. 
   The apparatus  10  described thus far may be modified or altered in manifold ways. Particularly for adapting the capacity, a different number of bag magazines  28 ,  29  is conceivable, along with suitably adapted bag extracting devices  36 , gripper devices  44 , and suction plates. The conveyor system  11  may also be embodied in a straight line, for instance. 
   The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.