Patent Publication Number: US-2018036782-A1

Title: Deep-drawing machine with rotation cutting device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority to European Patent Application No. 16182488.3, filed on Aug. 3, 2016, to Elmar Ehrmann and Robert Maier, currently pending, the entire disclosure of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a deep-drawing machine having a rotation cutting device, and a method for the operation thereof. 
     BACKGROUND OF THE INVENTION 
     Rotation punching devices to cut, to punch or to notch a film sheet between a cutting roller and an opposing roller are known from DD 297 112 A5, DE 39 24 053 C2 or also DE 196 41 094 C1. 
     WO 2013/134495 A1 discloses a tray-sealing machine with a rotation cutting machine for cutting lid film sections that are sealed onto trays in order to create packages. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a deep-drawing machine with a rotation cutting device for cutting of sealed containers. 
     The deep-drawing machine according to the invention may comprise a forming station that is configured for forming containers into a first sheet-shaped material and a cutting station that is arranged downstream of the forming station in a working direction and configured to cut or to perforate the first sheet-shaped material between the containers. The deep-drawing machine according to the invention may include the cutting station having a rotation cutting device with a cutting cylinder and an opposing cylinder. An advantage is the lower space requirement of such a cutting station compared to known complete cutting stations. A further advantage is a decrease in film scrap or a decrease in the amount of film used, respectively, in particular when smaller portion packages are produced, because smaller spacing between neighboring packages are possible using a rotation cutting device than using the known complete cutting stations For example, spacing of 4 to 5 mm in complete cutting stations can be reduced to half in the device of the present invention. 
     In a further variant, the deep-drawing machine can have a sealing station that is configured for sealing the containers with a second sheet-shaped material. Therefore, the deep-drawing machine becomes a deep-drawing packaging machine. The cutting station can be arranged downstream of the sealing station in the working direction. 
     The cutting cylinder and the opposing cylinder are preferably connected to one another through a gear drive in order to require only one drive for both cylinders. In addition, the gear drive can have at least one adjustable two-part gear wheel to balance the gear backlash of the two gear wheels (for example, after a previous center distance adjustment) to be able to account for a diameter change caused by re-sharpening of the blades of the cutting cylinder. 
     The cutting cylinder and the opposing cylinder can be driven jointly or individually, preferably by one servo motor or one servo motor each, to be able to drive positions and velocity profiles that are as accurate as possible. 
     In this context, the deep-drawing machine can include a control with which the rotation cutting device and a film feed can be synchronized in relation to one another in a way that film feed tolerances can be balanced. This may occur when the printed design on the first and/or second sheet-shaped material, which are transported by the film feed and/or with bracket chains on both sides, differs in the length in such a way that the rotation cutting device and/or the blades have to be adjusted to the printed design in their position in order to perform a cut as exact as possible in relation to the printed design. Likewise, it can occur that the end positions of the film feed are different due to inertias, wear of the bracket chains or other negative influences onto the film feed system and hence also the different position of the printed design of the lower film. These tolerances can be balanced as well. 
     In a particularly advantageous embodiment, the cutting cylinder is formed for waste-free cutting between at least two packaging flanges neighboring in the production direction in order to minimize the film use. 
     The cutting cylinder may preferably be continuous, intermittent and/or reversibly drivable so that tolerances can also be balanced after a film feed in which the cutting cylinder has to be moved opposite to the production direction. 
     The cutting station may have an ejection device, for example in form of a roller, in order not to cut packages in a completely circumferential way but to perforate them in a way that they still remain attached to the film structure or to the lower film until the ejection device separates the packages from the film structure or the lower film sheet. 
     The rotation cutting device may be configured to cut different formats of packages with different draw-off lengths. A draw-off length as used in the following shall be a length of the sheet-shaped material that is conveyed further in one work cycle of the deep-drawing machine. This means that the sheet-shaped material is conveyed further in each work cycle by the draw-off length intended for the respective work cycle. In sealed packages, the rotation cutting device can also be adaptable to cut edge seals. 
     The cutting cylinder may have a magnetic shell surface onto which a cutting plate can be installed. In this process, the length of the cutting plate and/or the blades can have a distribution and/or length that are different than the draw-off lengths of the film feed. The movement of the cutting cylinder can be adapted to the movement of the film feed by the control in a way that this difference can be balanced dynamically for each packaging or each format during the movement of the cutting cylinder and the film feed. 
     The control can comprise an adjustable electronic transmission factor to synchronize the film transport with the rotation cutting device. Hence, general existing differences in length between the film feed and/or printed design of the lower film and the distribution of the blades on the cutting cylinder can be adjusted in an extremely simple way. This can also take place automatically via a sensor system on the film feed and the cutting roller. 
     The rotation cutting device may comprise a reference sensor that records every rotation of the cutting cylinder. This is particularly advantageous for a calculation and/or determination of the electronic transmission factor. Using the reference sensor, referencing of the cutting cylinder and/or of its servo motor can take place also during the start of the machine. 
     A method according to the invention for the operation of a deep-drawing machine may comprise forming containers into a first sheet-shaped material by a forming station, and may also include cutting or perforating the sheet-shaped materials between the containers after forming of the containers by a rotation cutting device. 
     In a further variant, the method can also comprise sealing of the containers with a second sheet-shaped material by a sealing station. Sealing may take place prior to cutting or perforation by the rotation cutting device. 
     It is expedient to dynamically synchronize the rotation cutting device with a film feed in order to enable exact cutting or separating of packages with regard to a printed design or a sealing seam. 
     In a particularly advantageous embodiment, the rotation cutting device is synchronized with a film feed using an electronic transmission factor, wherein the transmission factor is calculated and/or adjusted prior to (or during) each or every “n”-th film feed movement, wherein “n” can be in the range between 2 and 10 in one embodiment. 
     The rotation cutting device may perform a balancing rotation also while the film feed is standing still in order to cause a corrective movement in or opposite to the working direction of the cutting cylinder. 
     During intermittent operation, the film feed preferably stands still at times and together with the rotation cutting device. 
     Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
    
    
     
       DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       In the following, the invention will be described by means of embodiments with the enclosed drawings. The drawings show: 
         FIG. 1  is a schematic side view of one embodiment of deep-drawing machine in accordance with the teachings of the present invention; 
         FIG. 2  is a perspective view of one embodiment of a cutting station of a deep-drawing machine in accordance with the teachings of the present invention; 
         FIG. 3  is a perspective view of a portion of the cutting station of the deep-drawing machine of  FIG. 2 ; 
         FIG. 4  is a schematic view of one embodiment of the connection of different control components of a deep-drawing machine in accordance with the teachings of the present invention; 
         FIG. 5  is a perspective view of the cutting station of  FIG. 2  from a different viewpoint; 
         FIG. 6  is a perspective view of another embodiment of a rotation cutting device of a deep-drawing machine in accordance with the teachings of the present invention; 
         FIG. 7  is a perspective view of another embodiment of a rotation cutting device of a deep-drawing machine in accordance with the teachings of the present invention; and 
         FIG. 8  is a schematic side view of an embodiment of an ejection device in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. For purposes of clarity in illustrating the characteristics of the present invention, proportional relationships of the elements have not necessarily been maintained in the drawing figures. 
     The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
       FIG. 1  shows a schematic view of a deep-drawing machine  1 . This deep-drawing machine  1  has a forming station  2 , a sealing station  3  and a cutting station  4  that are arranged in this order in a working direction R on a machine rack  6 . At the input side, there is a feed roll  7  on a machine rack  6  from which a first sheet-shaped material  8  is pulled off. In the area of the sealing station  3 , a material buffer  9  is provided from which a second sheet-shaped material  10  is pulled off as a lid film. On the output side of the packaging machine, a discharge device  13  (see  FIG. 2 ) is provided by means of which finished, individual packages  21  are transported away. Further, the packaging machine  1  has a feed device that is not displayed and that takes up the first sheet-shaped material  8  and intermittently transports it further in the working direction R in each main work cycle. The feed device can be implemented in form of laterally disposed transport chains. 
     In the displayed embodiment, the forming station  2  is formed as a deep-drawing station in which containers  14  are formed in the first sheet-shaped material  8  through deep-drawing. In this context, the forming station  2  can be adapted in a way that several containers are formed next to one another in the direction that is perpendicular to the working direction R. The machine consequently has multiple lanes. In the working direction R behind the forming station  2 , a loading track  15  is provided in which the containers  14  formed in the first sheet-shaped material  8  are filled with product  16 . 
     The sealing station  3  has a sealable chamber  17  in which the atmosphere in the containers  14  can be exchanged prior to sealing by gas flushing with a replacement gas or a replacement gas mixture. 
     The cutting station  4  is configured to cut or to perforate the sheet-shaped materials  8 ,  10  between the containers  14 . It can be provided for the containers  14  to be individualized directly after a cutting process, i.e. that they can only be conveyed further individually. However, it can also be provided that the containers  14  can be conveyed further in groups directly after the cutting process. For this purpose, one or multiple material bond connections such as residual bridges, which can be left in place during cutting or perforating, can be provided between the containers  14 . As shown in  FIG. 2 , to perform the cutting process, the cutting station  4  comprises a rotation cutting device  23  that will be described in even greater detail in the following. 
     In particular if the containers  14  are conveyed further in groups, the cutting station  4  can comprise an ejection device  5  (displayed in  FIG. 2  and  FIG. 3 ). This ejection device can then be configured for final individualization of the containers  14 . Even if an individualization of the containers  14  is provided directly after the cutting process, an ejection device  5  can be provided to separate incompletely detached containers  14  completely from cutting residues of the sheet-shaped materials  8 ,  10  or from other containers  14 . The ejection device  5  will also be described in even greater detail in the following. 
     Turning back to  FIG. 1 , the packaging machine  1  further has a control  18 . Its function is to control and to monitor the processes that take place in the packaging machine  1 . A display device  19  with operating elements  20  is used for visualizing and/or influencing the process workflows in the packaging machine  1  for and/or by an operator. 
     The general working principle of the packaging machine  1  will be explained briefly in the following. 
     As shown in  FIG. 1 , the first sheet-shaped material  8  is pulled off from the feed roller  7  and transported into the forming station  2  by the feed device. In the forming station  2 , containers  14  are formed in the first sheet-shaped material  8  by deep-drawing. The formed containers  14  have packaging flanges  34  on which they are connected to one another. Together with the surrounding area of the first sheet-shaped material  8 , the containers  14  are transported, in a main working cycle, further to the loading track  15 , in which they are filled with product  16 . 
     Subsequently, the filled containers  14  and the area of the first sheet-shaped material  8  that surrounds them are transported further through the feed device into the sealing station  3  in the main working cycle. After a sealing process to the first sheet-shaped material  8 , the second sheet-shaped material  10  is transported further as a lid film by the feed movement of the first sheet-shaped material  8 . In this process, the second sheet-shaped material  10  is pulled off from the material buffer  9 . Closed packages  21  are formed through sealing the lid film  10  onto the containers  14 . These closed packages can now be conveyed further in a composite film  11 . The intermittently working feed device transports the composite film  11  with the packages  21  in the working direction R towards the cutting station  4 . 
       FIG. 2  illustrates the cutting station  4  in a detailed perspective view. The discharge device  13  can be seen in form of a conveyor belt that transports finished and individualized packages  21  away from the cutting station  4 . A second discharge device  22  is indicated. It can be used to provide for a second discharge stream for finished and individualized packages  21 , for example for packages  21  sorted out due to faults. As can be seen in  FIG. 2 , the cutting station  4  has a rotation cutting device  23 . As in the embodiment shown in  FIG. 2 , this rotation cutting device can have a cutting cylinder  24  and an opposing cylinder  25 . The cylinders  24 ,  25  can have a common drive. For example, only one of the cylinders  24 ,  25  can be driven directly. The other one can in that case be drivable directly via a central gear box (see  FIG. 3 ). 
     The composite film  11  sealed together in the sealing station  3  and having the containers  14  is supplied to the cutting station  4 , in particular to the rotation cutting device  23 . The composite film  11  is cut or perforated between the containers there. This can take place in a way that the containers  14  are individualized i.e. are no longer connected, directly downstream of the rotation cutting device  23 . The present embodiment provides, however, that the composite film  11  is cut or perforated in a way that the containers  14  are conveyed further with the entire composite film  11 . For final individualization, the ejection device  5  is provided in the present embodiment. The ejection device  5  is located downstream of the rotation cutting device  23  and upstream of the discharge device  13 . However, it is equally possible for the ejection device  5  to be provided at a completely different place and for the composite film  11  to be subjected to further processing steps prior to final isolation by the ejection device  5 . 
       FIG. 3  shows a detailed view of the rotation cutting device  23 . Here it can be seen more clearly that the composite film  11  has several lanes  26  of containers  14 . In the present embodiment, the lanes  26  are aligned in parallel to the working direction R and disposed next to one another perpendicularly to the working direction R. In the present embodiment, the containers  14  therefore form rows  27  that extend perpendicularly to the working direction R. In particular the rows  27  but also the tracks  26 , however, can also be provided at any suitable angle to the working direction R. Recurring patterns of tracks  26  and rows  27  can be provided, which can be referred to as format  35 . They can repeat themselves at a distance of one draw-off length. 
       FIG. 4  schematically illustrates the closed- or open-loop control of the rotation cutting device  23  and of a film feeding device  28 . The rotation cutting device  23  can comprise a reference sensor  29 . Said reference sensor  29  can be configured for recording each full rotation of the cutting cylinder  24 . In addition, the rotation cutting device  23  can have a cutting drive  30 , preferably a servo motor. Said cutting drive  30  can preferably be designed in a way as to drive the cutting cylinder  24  or the opposing cylinder  25 . The respective other cylinder can then be driven indirectly via a transmission. The film feeding device  28  can comprise a film drive  31 . Moreover, it can have a film feeding sensor  32 , for example a rotary encoder. Said rotary encoder can be configured to record the film feed of the first sheet-shaped material  8  and/or the second sheet-shaped material  10  and/or the feed of the composite film  11 . As shown in  FIG. 4 , the reference sensor  29 , the cutting drive  30 , the film drive  31  and the film feeding sensor  32  can be connected to the control  18 . In this context, the control  18  can receive signals from the sensors  29 ,  32  and/or send signals to the drives  30 ,  31 . 
     In a possible variant, the cutting drive  30  and the film drive  31  are coupled to one another electronically. In this process, an electronic transmission factor  33  can be provided that provides a suitable desired ratio for the movement velocities and/or directions of the drives  30 ,  31 . The electronic transmission factor  33  can therein be selectable manually. However, an automated setting, for example by the control  18 , is equally possible. 
       FIG. 5  shows the deep-drawing machine  1  according to the invention from a perspective that is opposite to the perspective from  FIG. 2  to better illustrate the gear drive  36 . In the present embodiment, it comprises a first gear wheel  37  that is connected to the cutting cylinder  24  and a second gear wheel  38  that is connected to the opposing cylinder  25 . The cutting drive  30  can be assigned to the first gear wheel  37  or to the second gear wheel  38 . The first gear wheel  37  combs with the second gear wheel  38  so that both can be driven directly or indirectly by the cutting drive. 
       FIG. 6  shows a rotation cutting device  23  according to a further embodiment. Apart from the differences mentioned in the following, it can have all features of the embodiments described before or only a part of said features. It can consequently be combined with all previously described features. In  FIG. 6 , the first gear wheel  37  comprises a two-part gear wheel  37   a ,  37   b . However, it is also conceivable that the second gear wheel  38  comprises a two-part gear wheel. Through turning of the gear wheels  37   a ,  37   b  opposite to one another around their rotation axis, a potentially formed gear backlash can be balanced. 
       FIG. 6  in addition shows bearer rings  39  that are provided on the cutting cylinder  24 . Bearer rings  40  are also provided on the opposing cylinder but only one of them is visible. The bearer rings  39 ,  40  are used to set the (cutting) distance and the contact pressure of the cylinders  24 ,  25  in relation to one another. During grinding (sharpening) of the two cylinders  24 ,  25 , the bearer rings  39 ,  40  are ground as well. 
     Although the bearer rings  39 ,  40  and the two-part gear wheel  37   a ,  37   b  are shown in combination in the present embodiment, the skilled person will recognize that they can also be provided independently of each other. 
       FIG. 7  displays a rotation cutting device  23  according to a further embodiment. Apart from the differences mentioned in the following, it can have all features of the embodiments described before or only a part of said features. Here, the cutting drive  30  comprises a first servo motor  41 , which drives the cutting cylinder  24 , and a second servo motor  42  that drives the opposing cylinder  25 . The rotation ratio of the two cylinders  24 ,  25  can, therefore, be set or adjusted flexibly in this way by means of the control  18 . 
       FIG. 8  shows an alternative embodiment of the ejection device  5  in form of an ejection station  50  for separating a plurality, preferably a format  35 , of packages  21  from the composite film  11 . The ejection station comprises a liftable ejection plate  51  that is lifted upwards against an opposing contact plate  52  for ejecting the packages  21 . The individualized packages  21  are supported by recesses  53  in the ejection plate  51  in order to be taken out of the ejection station  50  by a gripper  54 . In this process, individual vacuum suction devices  55  of the gripper  54  dip through openings  56  to the packages  21  in order to suck said packages and take them out of the ejection station  50 . Subsequently, the residual film grid  11 ′ may be wound up by means of a residual film coil  57 . 
     Even if a sealing station  3  is provided in all of the described embodiments, the skilled person will recognize that sealing station  3  is not essential for the invention. Consequently, embodiments of the invention in which no sealing station  3  is provided and/or in which the containers  14  are not sealed are conceivable. The advantages of the invention can therefore also be achieved without sealing the containers  14 . Also an ejection station  50  according to the embodiment described with reference to  FIG. 8  can be provided in combination with unsealed containers  14 . In this case, floors of the containers  14  can be sucked instead of the packages  21 . A format  35  separated this way could also be stacked. 
     From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the invention may be made without departing from the scope thereof, it is also to be understood that all matters herein set forth or shown in the accompanying drawings are to be interpreted as illustrative and not limiting. 
     The constructions and methods described above and illustrated in the drawings are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.