Abstract:
A method for producing stand-up blister packages, and in particular a stable, easy-to-fill stand-up blister package that has no undercut of the blister dome, and can be produced with a high cycle number, without malfunctions and with a good, reproducible quality, in hot-seal machines. For this purpose, a fold line is produced through the heating of a linear region, independently of the heating during the process of sealing the blister edges with the carrier part. The apparatus has a corresponding heating station for heating and creating a fold line in the blister dome.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of German Patent Application No. 100 33 796.1 filed Jul. 12, 2000, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a method for producing stand-up blister packages, in which method blister domes are shaped from a film sheet of thermoplastic plastic, separated from the film sheet, transferred into circulating, cyclically-moved sealing pallets, and filled and sealed with a carrier part through large-surface heating of the blister edges. The invention additionally relates to an apparatus for executing the method. The stand-up blister packages produced with the method have a high market appeal, because the consumer can easily read and identify the imprint on the carrier part when the. stand-up blister packages are arranged appropriately in store shelves. 
     A method of the above described type and an apparatus for generally carrying out that method are described in German laid open application DE 37 22 214 A 1. The blister packages produced with the method and apparatus have a blister edge that extends around the entire perimeter and protrudes over the entire contour of the blister dome, and prevents the packages from being displayed in an eye-catching, compact manner, namely, being stood up on a side wall of the blister dome. 
     U.S. Pat. No. 4,901,858 discloses a stand-up blister package in which the four blister edges are sealed with a carrier part. The provision of an undercut on one side of the blister dome, the undercut being approximately as wide as the blister edge, lends the package the stability required for standing. This undercut hinders the shaping of the blister dome, because it necessitates horizontal movements of the tool parts. Sealing the blister edge in the region of the undercut in the sealing station of an automatic blister-package machine also requires complicated tools with horizontally-moving parts, because the heated sealing electrode requires a countersurface for sealing. This countersurface must, however, be moved away laterally before it is moved downward. Because the blister dome must often be adapted precisely to the item to be packaged, a deviation in forming the undercut is unacceptable as a rule. The item would be too loosely packaged. 
     U.S. Pat. No. 3,093,244 proposes sealing all four blister edges of the blister dome with the carrier part and folding one of the sealed edges by about 90°. These stand-up blister packages lack stability, because the folded sealed edge is not secured. The edge therefore bends back to varying degrees, so the stand-up blister packages appear crooked, which has a negative visual effect. If the folded sealed edge were to be secured with suitable measures, the stand-up blister packages would be very bulky and difficult to stack, and would require considerable space for shipping from the packaging site to the retailer. 
     It is the object of the invention to execute the method to produce blister packages in which a blister edge only protrudes on three sides of the blister dome. On the fourth side, the blister edge is intended to be brought into a fixed position, so the blister package can stand directly on the side wall of the blister dome on this side. It should not be necessary to create an undercut in the blister dome. The blister packages are supposed to be packed compactly. 
     SUMMARY OF THE INVENTION 
     The above object generally is achieved according to a first aspect of the invention by a method for producing stand-up blister packages, in which blister domes with blister edges are shaped from a film sheet of thermoplastic plastic, separated from the film sheet, transferred into circulating, cyclically-moved sealing pallets, filled with an item and sealed with a carrier part through the large-surface heating of the blister edges, with the method including the following method steps: 
     sealing one of the blister edges with the carrier part in a transverse-sealing station; 
     cooling the one blister edge and the carrier part to form a stand-up blister package pre-form; 
     linearly heating the transition region of the one blister edge between the blister dome and the carrier part in a heating station to form a narrow, heated fold line; 
     folding the carrier part and the one blister edge connected thereto by 180° along the heated fold line; and, 
     sealing the remaining blister edges with the carrier part to form the sealed stand-up blister package. 
     The above object generally is achieved according to a second aspect of the invention by an apparatus for producing stand-up blister packages according to the method of the invention including a shaping portion or section for providing shaped blister domes having blister edges; and a sealing portion or section with at least one circulating pallet belt having pallets with openings for receiving the blister domes and carrier portions on a surface of the pallets such that one blister edge overlaps a portion of a respective associated carrier, in the region of the at least one circulating pallet belt, a filling station, a transverse-sealing station for sealing the one blister edge with the carrier part, a folding station for folding the carrier part by 180°, a sealing station for sealing the other blister edges with the carrier part, and a heating station that is disposed between the transverse-sealing station and the folding station, with the heating station having a heated heating strip for warming a linear region of the blister dome in order to create a heated fold line. Advantageous modifications of the invention are disclosed and described. 
     The method is described in detail by use of schematic drawings of the apparatus for executing the method. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a portion of the apparatus for executing the method. 
     FIG. 2 is a side view of the remainder of the apparatus of FIG.  1 . 
     FIG. 3 is an enlarged representation of a portion of the transverse-sealing device. 
     FIG. 4 is an enlarged representation of the folding device. 
     FIG. 5 is a section through a stand-up blister package. 
     FIG. 6 is an enlarged representation of the positioning station. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 1, there is shown an apparatus for executing the method which generally comprises the shaping section  1  and the sealing section  2 . Disposed in the shaping section  1 , in sequence, are a heating device  3 , a shaping device  4 , a longitudinal-cutting device  5 , a transport device  6 , a transverse-cutting device  7  and a transfer device  8 . The sealing section  2  comprises two cyclically-moving pallet belts  9 ,  10  having circulating pallets  11  mounted thereon. These pallets  11  have a row of holes or openings, corresponding to the shape of the blister domes  12  inserted into them by the transfer device  8 . In the region of the first pallet belt  9 , following the insertion in the feed direction, is a positioning station  13  for the carrier parts of carrier  14 , preferably comprising cardboard, which are kept stacked in a magazine  15 , and removed individually by a transfer device  16  and placed onto the pallets  11 , one for each blister dome  12 . 
     Disposed beneath the plane of the pallets  11  on the upper reach of the belt  9  in the region of the positioning station  13  is a lifting device  17  (FIG. 6) comprising a holding device  18  with suction elements  57  for securely holding each blister dome  12  of a row seated on a holding strip  20  that can pivot about a point of rotation  19 . The point of rotation  19 , and thus the holding strip  20 , are additionally embodied to be vertically displaced by a drive  21 . 
     Following in the direction of passage is a transverse-sealing device  22  having a sealing electrode  23 , which can be adjusted in height, and—if necessary—a counter-strip  24 , which also can be adjusted in height for sealing one edge of a blister dome  12  to its associated carrier  14 . The first pallet belt  9  ends with a lifting station  25 , while the second pallet belt  10  begins with an insertion station  26 . A transfer device  27 , represented by an arrow, serves to remove the pre-formed stand-up blister packages  28 , each comprising a blister dome  12  and attached carrier  14 , from the pallet belt  9  and inserting them into the pallet openings of the pallet belt  10 . Following the insertion station  26  is a filling station  29 , in which the item  51  to be packaged is inserted into the blister domes  12 . Adjoining this station is a heating station  30  with a heated heating strip  31  that can be adjusted in height, and—if necessary—an oppositely-located counter-strip  32 , which can likewise be adjusted in height. FIG. 3 is an enlarged representation of the heating station  30 . 
     The folding station  33 , shown on an enlarged scale in FIG. 4, follows the heating station  30 . Disposed beneath the blister domes  12  in the folding station  33  is a holding device  34  comprising suction elements  35 , which are seated on a transverse strip  37  that can be adjusted in height by the drive  36 . The suction elements  35  can be connected intermittently to a vacuum source (not shown). A tilting device  38  comprising pins  39 , a strip  40  that supports  39  the pins and a drive  41  for vertically displacing the strip  40  is seated beneath the sealed-on carrier part  14 . Above the transport plane of the pallets  11  is a bending device  42 , which comprises a bending strip  43  that is seated on carriers  44  that are guided on guides  45  and can be displaced horizontally by a drive, not shown, and vertically lowered by a second drive. 
     A sealing station  59  having a sealing electrode  46  adjoins the folding station  33 . The electrode can be heated, and adjusted in height by a drive, not shown, to come into contact with the pallets  11 . If needed, a countersurface  60  is provided. 
     The method is executed as follows: 
     In the shaping section  1 , blister domes  12  are shaped in the mold  34  from the heated sheet  48  drawn from a roll  47 , and severed from the sheet in cutting stations  5  and  7 . The transfer device  8  grasps the severed blister domes  12  and spreads them in the transverse direction while transferring them into the openings of pallets  11  of the pallet belt  9 . The blister domes  12  are thus spaced from one another in the transverse direction. After the pallets  11  have been transported into the positioning station  13 , the blister domes  12  located in the pallets  11  are raised by the lifting device  17  such that the associated carrier parts  14  can be positioned on the pallets  11  (indicated by a dot-dash line), and when the blister domes  12  are re-lowered, one blister edge  49  rests on the associated carrier part  14 , overlapping it. After a further transport step, the two parts come to a stop in the transverse-sealing device  22 , and a large-surface seal is effected between the sealing edge  49  and the carrier part  14 . The transfer device  27  subsequently transfers the two sealed parts, as a so-called stand-up blister package preform  28 , into the second pallet belt  10 . The pallet belt  10  guides the pallets  11  to the filling station  29 , in which the item  51  is manually or automatically placed into the blister dome  12  of the package. 
     In the heating station  30 , (See FIG. 3) the heating strip  31  heats a linear region of the blister edge  49  in the region that is not sealed with the carrier part  14  in order to form a fold line  53 . The heating strip  31  preferably tapers to a slightly-rounded point, and is pressed against the blister edge  49  with an adjustable force, e.g., by a pneumatic cylinder with an adjustable pressure, so that a small groove  52  is formed as a fold line  53  during the heating process to permit the blister edge  49  to be folded back slightly). 
     In the next station, the folding station  33 , the blister domes  12  are first held securely by the holding device  34  (position shown in FIG. 4) so that, when the pins  39  are raised, the carrier part  14  and the blister edge  49  buckle in the region of the fold line  53  (shown as a dot-dash line). The horizontal displacement of the bending strip  43  effects a further bending at the fold line  53 . This position is also shown as a dot-dash line. The bending strip  43  is lowered (indicated by an arrow), and the bending continues to 180°. 
     In the downstream sealing station  59 , the sealing electrode  46  is used to seal the three remaining blister edges  50  with the carrier part  14 . A transfer device  61  (represented by an arrow) grasps the stand-up blister packages  5 B in the adjoining lifting station  55 , and places them onto a transport belt  56  or into cartons. 
     Thus, a stand-up blister package  58  is formed, which offers an appealing appearance when placed on a surface  54 , as shown in FIG.  5 . 
     During the transport of the blister domes  12  from the transverse-sealing station  22  to the heating station  30 , the sealed blister edge  49  and the adjoining region of the blister dome  12  typically cool to the extent that they do not impede the bending at the fold line  53 . Should this not be adequate in certain cases, a cooled plate can be placed onto the sealed region in an interposed station in order to accelerate the cooling process. 
     Two pallet belts  9 ,  10  are provided in the illustrated example. It is also possible in principle to position all of the stations in a single pallet belt of an appropriate length. 
     Also shown is a single-row arrangement of blister domes  12  for each pallet  11 . In other words, one row of blister domes  12  is shaped, severed and placed onto each pallet  11  per cycle. A double-row arrangement of blister domes  12  is conceivable when double-blisters are shaped, separated from the film sheet  48  and split in an interposed transverse-cutting device, spaced from one another in the transport direction and then inserted into the pallet belt  9  in double rows. 
     Two stations, the folding station  33 . and a subsequent sealing station  59 , are provided for folding the carrier part  14  and sealing it with the blister edges  50 . It is possible in principle to provide a combination folding/sealing station by arranging the bending strip  43  to execute a correspondingly large horizontal displacement movement and a small vertical movement, and disposing the sealing electrode  46  above the bending device  42  (shown in a dot-dash line in FIG.  4 ). After the carrier part  14  has been bent by the horizontal displacement of the bending strip  43 , the sealing electrode  46  travels downward, thereby completing the folding process and, immediately thereafter, effecting the sealing process. 
     The invention now being fully described, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.