Abstract:
A device for producing blowmolded container products ( 11 ) from plastic material, using single mold parts ( 7 ) movable along a production line ( 5 ) and in pairs toward one another and away from one another to close or open a production mold. The container products ( 11 ) are molded and exit after the demolding procedure in the form of a container chain ( 9 ) moved along the production line ( 5 ). A demolding unit ( 3 ) engages the exiting container chain ( 9 ) outside the production mold to support the demolding procedure. The demolding unit ( 3 ) has a force drive ( 17 ) deflecting the container chain ( 9 ) out of the production line ( 5 ) into back and forth movement.

Description:
The invention relates to a device for producing blowmolded container products from plastic material by individual mold halves movable along a production line and in pairs toward one another and away from one another to close and/or open a production mold in which the container products are molded. Following the demolding process, the container products emerge in the form of a container chain moved along the production line. To facilitate the demolding process, a demolding unit acts on the emerging container chain outside the production mold. 
     Methods and devices for manufacturing plastic container products are known in the prior art (DE 199 26 329 A1). To manufacture such products, a tube of plasticized plastic material is extruded into a molding device. One end of the tube is closed by heat sealing. The closed end tube is expanded by generating a pneumatic pressure gradient acting on the tube and applied to the molding walls of the molding device. The molding device comprises two opposite individual molding halves to form the container. In carrying out the bottelpack® method known in this technical field, the respective plastic container is filled under sterile conditions in the molding device by a suitable charging mandrel. After the charging mandrel has been removed, the filled container is hermetically sealed, and a specific head geometry is formed. For forming the actual plastic container in which fluid is later stored, two individual mold halves in the form of molding jaws may be moved toward one another by, for example, hydraulic or servo-electric drive, to achieve a closing position and away in opposite directions from one another into one of their opening positions. To achieve very high ejection rates of container products, DE 103 23 335 A1 describes a multi-station arrangement, where the various molding steps are divided among different stations arranged one after the other in an imaginary circular arc to form a type of carousel arrangement. This arrangement permits very high cycle frequencies for the plastic products to be ejected. In such systems these plastic products emerge in the form of a container chain along a production line. 
     A suitable synthetic plastic material for the container products is typically polyethylene, which can be processed quite well in such production systems and is, therefore, preferred. However, the use of polyethylene as a material for containers causes problems if the fill material filling the respective container product is a liquid that is to be autoclaved at 121° C. This problem is especially present, for example, for a highly sensitive pharmaceutical composition. In such cases, the prior art makes sure that, for example, the fill orifice of the container tube is covered by a sterile barrier at least from the time of the orifice&#39;s formation up to the filling of the associated container in a cleanroom. In this case, good results can be achieved, if, as described in DE 10 2004 004 755 A1, a sterile medium is conveyed by the barrier in the direction of the container fill orifice using a medium conveying device in order to improve the sterility. Another or an additional strategy for enhancing the sterility is simply to provide higher processing temperatures, for example, during the production of the tube for the container product or during the filling process of the fill material. However, such a procedure conflicts with the temperature sensitivity of the polyethylene provided as the synthetic plastic material. 
     Since the processing temperature of the polypropylene material is much higher than that of polyethylene and since a higher autoclaving temperature of 121° C. is possible, the sterility requirements can be satisfied in a simple and cost-efficient way. However, considerable processing problems present an obstacle to the use of polypropylene. 
     Due to the much higher outlet temperatures resulting from the use of a propylene material, and due to the resulting stiffer surface finish as compared to containers made of polyethylene, difficulties occur in separating the containers from the respective walls of the production mold. To remedy these difficulties, document DE 21 65 816 C3 proposes a device for producing molded, continuous, and contiguous containers made of polypropylene material. A demolding unit has a conveying device acting on the emerging container chain outside the production mold and imparting to the container chain a draw-off speed less than the speed of movement of the production mold. As a result of this procedure, the containers experience an elastic contraction that in turn is designed to facilitate the separation of the containers from the walls of the mold. However, this approach does not ensure that the demolding process will run efficiently, especially when high cycle frequencies are to be achieved. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a device permitting production of container products from polypropylene material in a simple, economical, and reliable manner. 
     The invention basically achieves this object with a device having a demolding unit with a power drive. By the demolding unit, the container chain can be deflected out of the production line into a back-and-forth movement. The container chain then undergoes a shaking or oscillatory motion in the outlet area so that the separation from the walls of the mold is guaranteed even at the high cycle frequencies required for an efficient operation. 
     In these circumstances, the device is preferably configured such that the container chain can be deflected at least essentially in the direction of the closing and opening movements of the individual mold halves by the power drive of the demolding unit. Consequently, the container chain is put into an oscillatory motion extending transversely to the conveying direction. 
     In this respect, the device can be preferably configured such that the demolding unit has a driver arrangement. The driver arrangement is drive-coupled to the power drive and has two bearing surfaces. The container chain, moving along the production line, is guided on the bearing surfaces. The deflection forces can be transferred to the container chain over the bearing surfaces. 
     This driver arrangement can have a passage channel with the wall sections forming a skirt for the moving container chain as well as the bearing surfaces for the transfer of the deflection forces to the container chain. 
     In this respect, the device is preferably configured such that the passage channel has moveable wall sections that can be moved into a closed position corresponding to the closed skirt of the container chain, and into an open position. During the open position, the driver arrangement can be forced to engage with the container chain and to disengage from it. In this way, the device can be made ready for use in an especially easy way in that on startup of production, the driver arrangement with open wall sections of the passage channel is moved up to the container chain. Then, the passage channel is closed to form a skirt for the container chain. 
     The driver arrangement can have a support frame drive-connected to the motor serving as the power drive and forming the stationary wall sections of the passage channel. In this case, the moveable wall sections of the passage permitting opening and closing of the skirt are mounted on the support frame so that they can be pivoted between the open position and the closed position. 
     In the case of containers with a small volume, for example, ampules, the production process is typically configured such that a plurality of containers lying next to one another are molded simultaneously. They form a wide area container chain with a plurality of containers lying next to one another and are combined to form a container chain train. The device can be configured such that the length of the support frame is equal to or larger than the width of the container chain train and that the moveable wall sections can be hinged to the end regions of the support frame located laterally of the container chain train. 
     Furthermore, the device can be preferably configured such that the demolding unit is mounted to be adjustable in position on a device frame between a rest position located at a distance from the production line and a working position supporting the demolding process at the container chain or the container chain train. As a result, the outlet area of the production mold is freely accessible for maintenance or adjustment measures when the demolding unit is in the rest position. Due to the position adjustable arrangement, the demolding unit can be made ready for use in a simple way. For this position adjustment, the device carrier is a component of the demolding unit, can have mounted thereon both the guide tracks for the driver arrangement and the motor serving as the power drive, and can be mounted on the device frame to be pivotable about an axis extending perpendicular to the direction of the production line and parallel to the guide plane of the guide tracks. 
     For the pivot movements between the rest position and the working position of the demolding unit, preferably a pivot drive in the form of a linear drive is connected in an articulated manner to the device carrier at a distance from its pivot bearing as well as to an articulated point and is located on the device frame at a distance from the pivot bearing of the device carrier. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings which form a part of this disclosure: 
         FIG. 1  is a schematic, highly simplified side elevational view of a molding device according to one exemplary embodiment of the invention, with the demolding unit in the working position; 
         FIG. 2  is a side elevational view in section of one subsection of the production line of the device of  FIG. 1 , where the moveable individual mold halves can be moved into a position that closes the production mold where a container product along the line of an ampule is shown inside the production mold; 
         FIG. 3  is a top plan view in section of just the demolding unit of the device of  FIG. 1 , where a container chain emerging from the production mold in the form of a wide container chain train where a passage channel intended for the container chain train and having closed wall sections, indicated by dashed lines, forms a closed skirt, and where the solid lines denote the moveable wall sections in their open position; and 
         FIG. 4  is a side elevational view of the demolding unit of  FIG. 3  in the working position, but with the wall sections of the passage channel in the open position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In  FIG. 1 , the production segment is located at the top in the figure. The subsequent demolding unit is connected to the top production segment in the downward direction. The production segment  1  involves a device for carrying out a blowmolding process in accordance with the bottelpack® system known from the prior art, and, specifically, in an embodiment, in which the various molding steps are carried out at a number of stations along a production line  5 . As in a carousel configuration, the individual mold halves  7 , of which only some are numbered in  FIG. 1 , are moved toward each other in pairs on an imaginary circular arc path to form a closed production mold, and are moved away from each other again to open the mold. Since systems that work according to the bottelpack® method are known from the prior art, no need exists at this point to provide additional technical details of the production segment  1  in  FIG. 1 . 
       FIG. 1  shows clearly that the resulting container chain  9  emerges from the production segment  1  along the production line  5  and then travels to the demolding unit  3 . As shown in  FIG. 3 , the illustrated container chain  9  covers a wide area. A plurality of individual containers  11  having an ampule-like shape ( FIG. 2 ), of which only a few are numbered in  FIG. 3 , next to one another in the container chain  9 . To facilitate the separation of the containers  11  from the walls of the individual mold halves  7  moving away from each other at the outlet area of the production segment, the demolding unit  3  imparts to the container chain  9  a deflecting movement, as indicated with the double arrow  13  in  FIG. 1 . For this purpose, the demolding unit  3  has a driver arrangement  15  producing, in drive connection with an electric drive motor  17  the deflection movement of the container chain  9  to reliably separate the containers  11  from the wall sections of the mold. 
     The full technical details of the demolding unit  3  and the driver arrangement  15  are shown more clearly in  FIGS. 3 and 4 . Driver arrangement  15  forms, with the support frame  19 , the stationary wall sections of a passage channel  21  ( FIG. 3 ) for the container chain  9  with the containers  11 . The movable wall sections  23  are pivoted on the support frame  19  and can be moved into an open position shown with the solid lines in  FIG. 3 . In this open position the container chain  9  can be moved easily into the open passage channel  21  to start up the device. The moveable wall sections  23  have angled frame legs  25  forming the hinge points at the ends of the support frame  19 . The length of these frame legs  25  is adapted to the thickness dimensions of the containers  11  of the container chain  9 . When the wall sections  23  are folded down into the closed position, as shown with the dashed line in  FIG. 3 , a form-fitting skirt of the container chain  9  is then formed in the passage channel  21 . 
     The support frame  19  of the driver arrangement  15  is guided on guide tracks  27  for the deflection movements extending according to the double arrow  13  in  FIGS. 1 and 4 . Like the motor  17 , these guide tracks are also mounted on a device carrier  29 , which in turn is mounted on a device frame  31  of the demolding unit  3  to be pivotable about a pivot axis or bearing  33 . At a distance from this pivot mounting, a linear drive  35  in the form of a hydraulic or pneumatic working cylinder is hinged at  28  on the device carrier  29 . This working cylinder in turn is supported on the device frame  31  at a hinge point  37  at a distance from the pivot bearing  33 . 
     Since the device carrier  29  of the demolding unit  3  is mounted in a pivotable manner on the device frame  31 , the demolding unit can be folded down from the working position, shown in  FIGS. 1 and 4 , into a rest position by retracting the power drive  35 , for adjustment and maintenance measures as well as preparation for startup. The driver arrangement  15  is located outside the outlet area of the container chain  9 . For the startup of the device, the device carrier  19  is moved into the working position, shown in  FIGS. 1 and 4 , by moving out the power drive  35 . Starting from the operating state shown in  FIG. 4 , the wall sections  23  in the open position are pivoted into the closed position to close the passage channel  21 , i.e., to form a skirt of the container chain  9 .  FIG. 3  shows the most clearly that the motor  17  has an output gear  39  with an eccentric device  41  converting the motor rotational movement into a reciprocating movement. Eccentric device  41  is coupled to the support frame  19  by adjustable push rods  43 . This gear system imparts to the support frame  19  and, thus, the container chain  9 , located in the passage channel  21 , a back-and-forth shaking motion. At the same time, it is possible to provide a stroke in the range of 10 to 20 mm long and, for example, one shuttle per second. In any case, the shaking motions in the outlet area of the container chain  9  ensure a reliable separation of the molded containers  11  from the walls of the mold, even if one uses materials, in particular polypropylene materials, that are difficult to demold and require high processing temperatures, or if the material to be demolded is very stiff. As a result, it is possible to exploit the advantages arising from the use of polypropylene materials, instead of polyethylene or a co-extruded multi-layered composite. These advantages are also due to the polypropylene material being able to be autoclaved at higher temperatures (121° C.). At the same time, it is even more advantageous to obtain the polypropylene material from just one extrusion head than it is to use the multi-layered systems referred to. 
     Instead of the depicted linear drive  35  in the form of a working cylinder for adjusting the position of the demolding unit  3  between the working position and the rest position, other kinds of drive and gear means can be provided. For example, a spindle drive and the like can be used. It is also possible to provide locking mechanisms that allow the demolding unit  3  to be releasably fixed in the working position and/or the rest position or in desired intermediate positions. 
     While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.