Patent Publication Number: US-6701692-B1

Title: Device for closing plastic bottles

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a device for sealing plastic bottles, especially PET bottles. 
     In the case of a known device of this type (FR A 2 653 408), the delivery device, the magazine and the sealing tool operate in one and the same plane above the plane of motion of the bottles. Moreover, the placement of the sealing blank and its sealing to the prepared bottle take place while the latter remains in its position. However, this delivery process is time-consuming, because the entire process, from fetching the sealing blank to placing it on the bottle and finally sealing the latter must be completed, because fetching the next sealing blank for a subsequent delivery process can be commenced only after the sealing process has been completed. 
     SUMMARY OF THE INVENTION 
     The invention is concerned with the problem of providing a device for sealing plastic bottles, especially PET bottles, which enables the sealing plate to be supplied and sealed completely to the filling opening of a bottle within one working cycle and with an increased output. 
     The inventive device is designed as a compact module, which, with an advantageous short conveying distance, is placed immediately behind a filling station, and enables a sealing blank to be supplied and sealed completely to the filling opening of the bottle in a single phase. As a result of the shifting of the working plane of the delivery device towards the center plane of the bottle, which is positioned for accommodating the sealing blank, the fetching of a sealing blank and downward motion of the latter to about the height of the opening of the prepared bottle can take place independently of the sealing process, the placement operation being reduced to a short lateral motion of a support for blanks. After the placement process, the sealing of a sealing blank, which has been put in place, and the bringing along of a subsequent sealing blank can take place simultaneously, independently of one another and, so that productivity is increased as a result of the shortened cycle. If the feeding and/or sealing process is interrupted, only a single defective, filled but not yet sealed, bottle must be discarded as waste from the conveyor track, so that loss remains low. 
    
    
     Further details and advantageous developments arise out of the following description and the drawing, in which an example of the object of invention is illustrated in detail diagrammatically. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a side view of a conveyor track of a bottling machine for plastic bottles, comprising several processing stations, 
     FIGS. 2 to  4  each show enlarged detailed representations to illustrate different sealing phases in the sealing station, and 
     FIG. 5 shows a plan view of two parallel sealing stations along a line V—V in FIG.  1 . 
    
    
     FIG. 1 shows a sealing device, which is labeled  1  as a whole, for plastic bottles  2 , especially are provided as PET bottles which, in a horizontal conveyor track F, by means of a conveyance (not shown in detail) in a clocked sequence, pass from an aseptic sterilizing area B into the area of a filling and gassing station  3 , from which the respective plastic bottle  2  reaches the processing position  2 ′ for a sealing process. In this area of the conveyor track F, a delivery device  6  is disposed, which is provided with a magazine  4  for the seals  5 , by means of which a seal  5  is taken from the magazine  4  and, after passing through a sterilization section, which is formed by a largely closed interior space  7  of the delivery device  6 , placed onto the filling opening  8  of the bottle  2 ′. Subsequently, the bottle  2 ′ is sealed by means of a sealing tool  9  (FIG.  2 ). 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the inventive sealing device  1 , the delivery device  6  is constructed so that the sealing blanks  5 , which are taken as seals from the magazine  4 , are shifted by a rotational motion D into the area of the filling opening  8  of the bottles  2 ′ provided. Within the residence time of the bottles  2 ′ provided until the next phase, the sealing blank  5  is placed onto the edge region around the filling opening  8  of the bottle  2 ′, which remains in its provided position, and sealed. 
     The enlarged sectional representations of FIGS. 2 to  5  illustrates that the delivery device  6  has a working plane A, which is displaced laterally to the vertical, center plane M of the bottles  2 ,  2 ′, parallel to the transporting direction of the bottles (arrow F′) (distance C, FIG.  3 ), along which the bottles  2 ,  2 ′ are cycled (distance T, FIG.  1 ). Moreover, the delivery device  6  is provided with supports  11  for the blanks which, for putting the sealing blank  5  in place, can be moved temporarily from the working plane A to the bottle  2 ′ on the filling track F in the plane M (FIG.  1 ). 
     The front view of FIG. 1 shows that the delivery device  6  comprises a star wheel  12  with supports  11  for the blanks, which are distributed over the periphery and in each case are constructed as angled suction pipes  13  (FIG.  2 ). With their end supporting the sealing blank  5 , these pipes can be shifted from the circular path (rotation D), forming the working plane A of the star wheel  12 , through a horizontal swiveling motion (arrow S, FIG. 5) into the center plane M of the prepared bottles  2 ′. For this purpose, in each case a single swiveling driving mechanism, such as a magnetic driving mechanism (not shown), or a joint driving means, such as a curve control (not shown), can be provided. The different phases of motion of the suction pipe  13  of FIGS. 2 to  4  together with FIG. 5 show that the support  11  for the blanks is supported so that it can be rotated at the star wheel  12 . 
     The side view of FIG. 2 shows the sealing tool  9  in the ready position above the filling opening  8 . It has a sealing head  14 , which can be moved vertically into and out of a sealing engagement (arrow G). At the lower end of the sealing head  14 , a guiding ring  15 , is provided. It projects over said head and, by means of a vertical motion (arrow G′), which is independent of the sealing head  14 , engages the region of the filling opening  8  (FIG.  3 ). Moreover, the sealing blank  5  is moved towards the bottle  2 ′ by the downward motion (arrow G′). During the sealing process, the sealing blank  5  is fixed by guiding ring  15  (FIG.  3 ), and the width of the ring (diameter of the opening) of the guiding ring  15  is dimensioned so that an unimpeded passage is provided for the sealing head  14 . 
     The guiding ring  15  is provided with a lateral recess (not shown), which, when said support is moved into the blank delivery position for the blanks (FIG.  2 ), forms one in the area of the ring wall  16  for the support  11  of the blanks, when the latter is swiveled into the position shown above the filling opening  8  of the prepared bottle  2 ′. 
     The phases of motion of FIGS. 2 to  4  show that the sealing head  14  of the sealing device  1  occupies a starting position above the guiding ring  15  in the starting position of the latter (FIG.  2 ). Even during the first sealing phase (FIG.  3 ), the sealing head  14  remains above the range of motion of the support  11  for the blanks, until latter is shifted over the filling opening  8  of the bottle  2 ′ and the guiding ring  15  is shifted by means of its support  15 ′ towards the bottle  2 ′ (lifting path H). Moreover, the sealing blank  5  is held by the suction pipe  13  and grasped at the edge by the guiding ring  15  so that the filling opening  8  is covered positionally accurately. The diameter R of the sealing blank  5  is selected so that the filling opening  8  and, with an overlapping portion of the sealing blank  5 , an edge region of the neck  17  of the bottle is overlapped. 
     After said placement of the sealing blank  5 , the support  11  for the blank is returned to its starting position (FIG. 1) and the sealing head  14 , which is constructed as a hotplate or the like, is lowered onto the sealing blank  5 , so that sealing takes place in the edge region of the opening  8 . Thereafter, the guiding ring  15  and the sealing head  14  together are returned to their starting position. 
     By means of the above-described sealing device  1 , the sealing blank  5  is put in place and connected gas-tight with the plastic bottle  2  in a single cycle of the machine. The sealing blank  5  is picked from the magazine  4  in such a manner, that subsequently the side of the sealing blank  5 , facing the bottle opening  8 , is sterilized completely and that, during this sterilization process, there is no contact whatsoever in the interior  7  of the delivery device  6  with other contaminated surfaces of the filling station. In particular, an H 2 O 2  aerosol is used for the sterilization. The sterilization takes place in the area of the sealing blank not taken hold of by the suction pipe  13 . In Particular, the suction pipe  13  does not take hold of the center of the sealing blank  5 , so that sterilization is also assured at the edge of the seal. Until the sealing blank  5  is placed on the filling opening  8  (FIG.  4 ), the side of the sealing blank  5  facing the product remains untouched, so that it cannot be re-contaminated. 
     The sealing device  1  has two subassemblies, which can be used independently of one another and consist of the delivery device  6  and the sealing tool  9 . The sealing head  14  (including an appropriate heater) is spatially separated from the delivery device  6 , which is provided in the region of the star wheel  12  with a sterilization device (not shown). One of these subassemblies is required for each of the conveyor track F (FIG.  5 ).