Abstract:
The invention relates to a two-chamber container, in particular as a non-resealable disposable packaging, wherein the two-chamber container has an inner chamber ( 1 ) and an outer chamber ( 2 ) surrounding the inner chamber ( 1 ), and a cap ( 3 ) produced by compression of plastics material, with which the upper edges of the wall of the inner chamber ( 1 ) and those of the outer chamber ( 2 ) are rigidly connected, the cap ( 3 ) having two separate channels ( 7   1   , 7   2 ), and the inner chamber ( 1 ) being arranged asymmetrically inside the outer chamber ( 2 ) in such a way that a portion of its wall is secured to the cap ( 3 ) in the region between the channels ( 7   1   , 7   2 ) in such a way that one channel ( 7   1   , 7   2 ) is connected to one of the chambers ( 1  or  2 ) in each case.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Applicant claims priority under 35 U.S.C. §119 of German Application No. 199 58 920.8, filed on Dec. 7, 1999. Applicant also claims priority under 35 U.S.C. §365 of PCT/EP00/12214, filed on Dec. 5, 2000. The international application under PCT article 21(2) was not published in English. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for producing two-chamber containers, with an inner mandrel and an outer mandrel, wherein the inner mandrel can be inserted into and withdrawn from the outer mandrel, a die cavity for a cap and a material feeder for supplying a heated portion of a thermoplastic polymer material into the die cavity of a compression mould. 
     2. The Prior Art 
     A device of this type is known from U.S. Pat. No. 5,219,373. Here, two separately produced one-piece tubes with different diameters are pushed onto their corresponding inner or outer mandrel respectively, so a cap with common outlet aperture is provided by means of injection moulding owing to a nozzle piece and is simultaneously connected to both tube ends. This method is time-consuming as a result of the many individual steps and, therefore, does not allow a high number of pieces to be produced per unit of time, in particular as the tubes are initially produced individually and have to be introduced into the device in a coordinated manner. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a device for producing two-chamber containers, in particular as non-resealable disposable packaging, which looks nice and can be produced simply and quickly. 
     This object is achieved by a device for producing two-chamber containers, with an inner mandrel and an outer mandrel, wherein the inner mandrel can be inserted into and withdrawn from the outer mandrel, a die cavity for the cap and a material feeder for supplying a heated portion of a thermoplastic polymer material into the die cavity of a compression mould. There is a device for winding a film around the driven-out inner mandrel and a device for winding a film around the outer mandrel and advanceable welding devices to produce longitudinal side seams to produce tubes. The mandrels can both be inserted into and withdrawn from the die cavity of the compression mould to produce a cap with a seal and for connection to the walls of the chambers formed. Each mandrel has a projection in the direction fo the die cavity for forming a channel in the cap connected to a chamber in each case. 
     In a preferred embodiment, the advanceable welding device has two opposing and pivotable welding jaws which have two jaw projections separated by a gap in each case, wherein a cutting device can be inserted into and withdrawn from the common gap. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in more detail below with the aid of an embodiment of a device for producing two-chamber containers. 
       In the drawing: 
         FIG. 1  shows a two-chamber container in side view; 
         FIG. 2  shows the two-chamber container illustrated in  FIG. 1  in plan view from above; 
         FIG. 3  shows a device for producing the two-chamber container in schematic view; 
         FIGS. 4   a, b, c  shows a mandrel system and its interaction with a pressing tool; 
         FIG. 5  shows a view from above onto the mandrel system with tubes; 
         FIG. 6  shows the supply of a strip of film round a mandrel for producing a side seam; 
         FIG. 7  shows the formation of a side seam on a film wound round a mandrel and its separation from the strip of film. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The two-chamber container illustrated in  FIG. 1  in the form of a disposable packaging for two components which are to be stored separately from one another but are to be used together, has an inner chamber  1  and an outer chamber  2  surrounding it, a cap  3  and a fastening seam  4  produced only after filling of the chambers  1  and  2  with different filling components, which fastening seam seals the chambers  1 ,  2  at the end remote from the cap  3  while separating them from one another. 
     The cap  3  has a shoulder  5  which, according to  FIG. 2 , has a laterally flattened, rounded cross-section which can also be rounded so as to be circular or oval. The cap  3  also has a—in this case central—neck  6  in which two channels  7 .sub. 1 ,  7 .sub. 2  are formed, of which one in each case is connected to one of the chambers  1  or  2 . A seal  8  is attached to the neck  6 , which seal is designed in the embodiment as a twist-off seal  9 . There is a predetermined breaking point  10  on part or all of the periphery of the neck  6  in order to facilitate twisting off. The twist-off seal  9  is preferably designed in such a way that when it is broken and the openings of the channels  7 .sub. 1 ,  7 .sub. 2  are thus exposed it remains connected to the cap  3 , in other words, it does not have to be disposed of separately. 
     The chamber  1  is produced from a tubular film  11  with smaller diameter and the outer surrounding chamber  2  from a tubular film  12  with larger diameter. As shown clearly in  FIGS. 1 and 2 , the tubular film  11  is secured by a portion of its wall to the insert  13  arranged centrally in this case, in which the channels  7 .sub. 1 ,  7 .sub. 2  are formed, so as to separate them from one another in such a way that each chamber  1 ,  2  is connected to only one channel  7 .sub. 1  or  7 .sub. 2 . 
     The workstations for producing a two-chamber container, as is described above for example, can be seen in FIG.  3 . In position I a film is wound round an inner mandrel and the film is welded to form a tube to produce the inner chamber  1 . At station II a film is wound round an outer mandrel and welded to form a tube by the production of a side weld seam to produce the outer chamber  2 . The inner tubular film can also be produced at station II and the outer tubular film at station I. This can optionally also take place at different heights, wherein both tubes must at least be transported into one plane. A portion of material, for example plastics material plasticised by heat, is supplied to a die cavity at station III. At station IV the inner mandrel and the outer mandrel are introduced, together with the inner and outer tube produced, into a die cavity where the cap is formed from the portion of material and is simultaneously connected to the two tube ends located in approximately one plane. Some or all of stations V to VII can be provided as cooling stations for curing and cooling of the cap. At station VIII the die is opened and the finished product removed and transported away. The described allocation of the production stages to the stations is to be considered as an example. Any other allocation of the processing stages is also possible. 
       FIG. 4  shows an outer mandrel  14  in which an inner mandrel  15  is arranged so it can be inserted and withdrawn. The outer die of the outer mandrel  14  corresponds to the inner die of the outer chamber  2  and that of the inner mandrel  15  to that of the inner chamber  1  (see  FIG. 5  also). The inner mandrel  15  and the outer mandrel  14  have cylindrical mandrel projections  16 .sub. 1 ,  16 .sub. 2  which are provided in the cap  3  to be attached to form the channels  7 .sub. 1 ,  7 .sub. 2  (see FIG.  1 ). When the inner mandrel  15  has been driven in the direction of the arrow in  FIG. 4   a  out of the outer mandrel  14  into its external end position, a strip of film or a portion thereof is wound round the driven-out inner mandrel  15  to form a tube which is sealed by a side seam  17 , preferably by welding. The side seam  17  can be produced as an overlapping seam or—as illustrated—as a parallel seam, wherein the start and the end of the film winding round the mandrel are aligned parallel to one another and then welded to one another for example by means of supplied welding tongs. With such an embodiment of the side seam  17  with parallel edges, the outer mandrel has a recess  18  which serves to receive the side seam  17  projecting somewhat radially when the inner mandrel  15  is retracted into the outer mandrel  14  (see  FIG. 4   b ). 
     In the position shown in  FIG. 4   b , both the inner mandrel  15  and the outer mandrel  14  provided with a side seam carry tubular films  11 ,  12  which project slightly beyond the free ends of the respective mandrels  14  and  15 . The mandrels  14 ,  15  equipped with tubular films  11 ,  12  in this way are simultaneously fed with their free ends into a die cavity  19  which reproduces the external form of a cap  3  with seal  8  which is to be moulded on. A portion of plasticised material, from which the cap  3  is to be produced, has previously been fed into the die cavity  19 . Owing to a movement of the mandrels  14 ,  15  into the die cavity  19  or of the die cavity  19  towards the mandrels  14 ,  15  or a common movement of mandrels  14 ,  15  and die cavity  19  towards one another, the cap  3  is moulded on by compression of the portion of material. In the process, the channel  7 .sub. 1  associated with the inner chamber  1  is formed by means of the projecting mandrel projection  16 .sub. 1  and accordingly the channel  7 .sub. 2  of the outer chamber  2  is formed by the mandrel projection  16 .sub. 2 . 
       FIGS. 6 and 7  show schematically the production of a tube. The production process illustrated is suitable in particular for very thin films, for example 75 micrometers (0.075 millimeters) thick. Such a strip of film  21  arranged on a roller  20  is guided over two rotatable fixed deflecting rollers  22 ,  23  and the start of the strip is wound onto a spool  24 . A mandrel  14  or  15 , arranged on a turntable, for example, can be inserted between the two deflection rollers  22 ,  23  in such a way that it deflects the strip of film  21  (see  FIG. 6 ) and is partially covered by it. In a certain position of the mandrel  14  and  15  with the deflected strip of film  21 , the two welding jaws  19  pivot inwards and, have a shape which is such that the mandrel  14 ,  15  is completely covered by the strip of film  21 . Each welding jaw  19 ,  19 ′ has jaw projections  26  which are separated, i.e. provided with a gap  25 . The shape of the jaw projections  26  is chosen such that the strip of film  21  covers the respective mandrel  14  or  15  completely and lies with two lateral edges parallel to one another, which lateral edges project perpendicular to the mandrel surface. A side seam  17 ′ of the adjacent lateral edges of the strip of film  21  is welded and formed by the welding jaws  19 ,  19 ′ lying opposite one another. The side seam  17 ′ formed between the opposing welding jaws  19 ,  19 ′ is divided by means of a knife  27  which can be introduced into the gap  25  between the jaw projections  26  and  26 ′ which are spaced apart from one another, in such a way that one portion produces the side seam itself and one portion remains connected to the strip of film  21  and can be wound on the spool  24 . 
     In the embodiment shown, in the inwardly pivoted state of the welding jaws  19 ,  19 ′, the retaining device for the knife  27  can be introduced into a guide in one of the welding jaws  19 ,  191  and can be moved up and down in the gap  25  of both welding jaws  19 ,  19 ′, the previously welded side seam  17 ′ being divided, as described above. 
     When the welding jaws  19 ,  19 ′ are pivoted away from the mandrel  14 ,  15  the mandrel  14 ,  15  now provided with a tube  11 ,  12  can be transported to the next workstation. The connected strip of film  21  can be clamped between the deflecting rollers  22 ,  23  (dashed line in  FIG. 6 ) with the separated side seam portions  28  by the drive of the spool  24 . A further portion of the strip of film  21  is unwound from the spool  20 , which portion is then looped again—as described above—by the mandrel  14 ′ ( FIG. 6 ) that follows on the turntable for example, and can be provided with a side weld seam  17 ′. By dividing the side seam  17 ′ formed a continuous strip remains which can be gradually wound onto the spool  24  and partially consists of the fresh strip of film  21  and partially of a portion of strip which has been divided up and comprises the side seam portions  28 . 
     The advantage of this solution lies in the fact that despite the side seam  17 ′ being cut by the knife  27  there is always a continuous strip which can be guided with a controllable tension by pulling (spool  24 ) and optionally with additional deceleration of the spool  20 . 
     The corresponding welding devices and film guides can be arranged at different heights to produce the inner tube and the outer tube, can be height adjustable and/or optionally arranged so as to also be axially displaceable or pivotable. 
     With sufficient rigidity, for example in a stronger, thicker film, winding round a mandrel can also take place in that an overlapping seam (not shown) can be provided which can be produced so as to be bonded, for example by applying an adhesive or a double-sided adhesive strip, or welded, for which purpose suitable supply and adhesion or welding devices and optionally cutting devices as well would have to be provided, which are all so familiar to a person skilled in the art that they do not need to be described in more detail here.