DE29906987U1 - Separating device for plastic films and a packaging machine comprising this separating device - Google Patents

Description

99/160 Dipl.-Chem. E.L. FRITZ 19.04.1999/BR/Sun Dr. Dipl.-Phys. R. BASFELD Patent attorneys Mühlenberg 74 59759 Arnsberg

company

Newpack

Packaging Systems GmbH

Erlenhof 1

D - 49143 Bissendorf

"Separating device for plastic films and a packaging machine comprising this separating device"

The present invention relates to a separating device for plastic films or similar material for use in a packaging machine, comprising at least one upper tool and at least one lower tool, as well as a packaging machine comprising this separating device.

A separating device of the aforementioned type is known from the utility model DE 80 14 554.

The packaging process as such essentially consists of a forming process in which a continuous film is formed by a corresponding forming tool into a film strand with evenly arranged recesses, which represent the containers to be filled. In the next step, these recesses are filled with a product to be packaged in an insertion section and then sealed with another, usually thinner continuous film in a sealing device.

The result is an endless strand of packaged goods, which must be cut with a suitable cutting device to the desired batch size, usually a single packaging unit. For this purpose, a cutting device for cutting plastic films is used. The cutting of the film in the running direction is usually carried out continuously by a circular knife arranged in the running direction, whereas the cutting across the running direction is carried out in a discontinuous process by punching. Here, the film strand is passed between a lower and an upper tool, which are equipped with a corresponding punching tool. A lifting mechanism moves either the lower or upper tool against each other 5 and cut by pressing the punching tools together. After this transverse cutting, the film strand is cut lengthwise by the circular knives.

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However, not every film material can be advantageously separated by punching. For this application, cutting devices equipped with appropriate cutting tools, such as so-called serrated knives, are used. By adjusting the cutting depth, perforations can even be produced in this way. According to the state of the art, in both cases a completely new separating device must be installed, which is equipped with an appropriate serrated or similar cutting knife. The existing separating device cannot continue to be used because the actual tool cannot be changed or can only be changed with considerable effort.

The problem of the present invention is therefore to provide a separating device which can be used more universally.

According to the invention, this problem is solved by a separating device with the characterizing features of claim 1.

By providing connecting means that allow a, preferably quickly detachable, connection of cutting devices for different purposes, a universally applicable separating device is provided that can meet any desired purpose and thus saves the investment in a second or even third separating device. In addition, the tool can be changed much more quickly than, for example, a complete separating device and the production process can be resumed more quickly.

The use of knurled screws as a connecting element proves to be particularly advantageous, as they can be loosened and tightened again by hand at any time without tools.

The fastening of the corresponding counter pressure bar with pins on the lifting plate also proves to be a quickly detachable but nevertheless sufficient connection.

By changing the punching or cutting tool and the corresponding counter-pressure bar together, optimal performance of the separating device is ensured.

Because the counter pressure bar for punching knives and the counter pressure bar for serrated knives can be attached to a lifting plate with grooves using pins, the counter pressure bar can be lifted and replaced relatively easily using a screwdriver.

The use of guides to support the lifting plate and the counter pressure bar allows for friction-free and safe guidance of these movement-intensive parts.

This movement is advantageously triggered by a pneumatically driven cylinder, which transfers its force via a corresponding lifting mechanism to the lifting plate or the counter-pressure bar attached to it.

In this context, the use of a sliding joint gear, which provides a maximum force at the top dead center of the travel path, proves to be particularly advantageous.

Two tension columns mounted in the direction of the travel path of the lifting plate are particularly suitable for the optimal fastening of the upper tool and for fastening the separating device in the machine frame of the packaging machine.

Thickened sections in the middle area of the tension columns and threads at the ends make

•ft

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the pull columns especially as mounting supports for lower and upper tools, as well as in connection with clamping pieces, which can be attached to the pull columns, for fastening in the machine frame.
5

A crossbeam fixed between the tension columns and by lock nuts serves as a support for the corresponding cutting or punching tool and for various other advantageous devices.

The retaining strips attached below the crossbar serve as a holder for a spacer bar, which in turn is equipped with corresponding springs so that the spacer bar can be pulled in or out of the holder without great effort and does not have to be held, for example by another person, during the change.

By using a spacer bar with continuous holes 0 to accommodate a knife carrier

for punching knives as well as a crossbar also provided with continuous holes, a removal of punching waste is provided, with the aid of, for example, a suction device.
25

The punching waste can advantageously be collected in a collecting tray which can be attached to the crossbeam.

0 In a particularly advantageous embodiment, the knife holder for serrated knives contains a hose membrane that can be pressurized with compressed air. By expanding the hose membrane, the knife is pushed out of the knife holder and perforates or cuts the film fed underneath by the counter-pressure bar.

In the following, the present invention is described in more detail using an embodiment with reference to the accompanying drawings.

Fig. 1 A sectional view of an inventive

Separating device in a punch design;

Fig. 2 is a plan view of a lower tool of a

Separating device in a punch design; 10

Fig. 3 is a sectional view III-III of a separating device according to the invention in a punch design;

Fig. 4 a separating device for plastic films according to the invention in an embodiment as

serrated knife;

Fig. 5 is a sectional view V-V of a separating device for plastic films according to the invention in a

0 Design as a serrated knife;

Fig. 6 shows a packaging machine with a separating device according to the invention.

First, reference is made to Fig. 6.

A separating device 32 according to the invention can be part of a packaging machine 26. A packaging machine 26, for example for foodstuffs to be sealed in plastic film, is formed by several work stations connected in series, which first process a lower film web 27 and, in the later work steps, also an upper film web 28. In the processing direction of the film web, a forming tool 30 is arranged as the first work station, which, for example, forms the lower film into a cup shape in a vacuum deep-drawing process. In the processing direction behind the forming tool 30 there is an insertion section 29 in which the foodstuffs to be packaged are placed in the now

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cup-shaped film web is inserted. The upper film web 28 is fed onto the lower film web 27 after the food to be packaged has been inserted and is welded to the lower film web 27 by means of a sealing station. Two or more circular knives 33, which are arranged in the transport direction of the film, separate the sealed packages in the longitudinal direction, after they have passed through a separating device 32 according to the invention.

The separating device 32 according to the invention essentially comprises an upper and a lower tool, which are connected to one another via two tension columns 16. The lower tool comprises the essential moving parts necessary for operation. In particular, this is a lifting plate 4, which can be moved vertically between suitable guides 5, and a counter-pressure bar 6 or 15, which can be detachably fastened to the lifting plate 4 with pins 19. Grooves 20 are provided between the lifting plate 4 and the counter-pressure bar 6 or 15, which make it easier to release the counter-pressure bar 6 or 15 from the lifting plate, for example using a screwdriver.

This unit consisting of a lifting plate 4 with a counter-pressure bar 6 or 15 attached is driven by a lifting mechanism 3, which in turn is actuated by a pneumatic cylinder 2. The lifting mechanism 3 is essentially a sliding joint gear that allows the lifting plate 4 to move up and down by appropriately controlling the cylinder 2, whereby a minimum travel distance but a maximum force is made available at the top dead center, so that the film can be cut through optimally.

The pull columns 16 are provided with threads at the ends and are each fastened with a nut in the receiving jaws 17 of the lower tool and protrude beyond the lower tool in the direction of movement of the counter-pressure bar 6 or 15. They

have a larger cross-section in the middle area for fastening in the machine frame 21 of a packaging machine. The tension columns 16 and thus the entire separating device for plastic films are fixed by clamping pieces 1, which can be clamped against the machine frame 21 by a nut.

The upper tool is arranged through corresponding holes between the upper threaded sections of the tension columns 16 and can also be clamped using two lock nuts and, to a small extent, variably fastened in its distance from the lower tool. The upper tool essentially comprises a crossbar 8, two knurled screws 12, two holding bars 11 and knife carriers 7 or 13 and spacer bars 10 or 14 corresponding to the area of application as a punch or serrated knife. The knife carrier 7 or 13 and the spacer bar 10 or 14 form a unit which can optionally be exchanged together with the corresponding counter-pressure bar 6 or 15 according to the area of application already mentioned above. In both cases, the spacer bar 10 or 14 can be pulled out in the direction of the machine outlet after loosening the knurled screws 12. The holding strips 11, which engage behind the lateral springs of the spacer bar 10 or 14, ensure appropriate guidance. In the locked state, the knurled screws 12 are screwed to threaded holes in the corresponding spacer bar 10 or 14, so that it is detachably connected to the crossbar 8 in a force-locking and form-locking manner. When used as a punch, the counter-pressure bar 6 consists of a profile with a rectangular cross section, which is pressed against the knife carrier 7 with an inserted punching knife 25 during operation, thus cutting through the film. The punching knife 25 has a recess into which the counter-pressure bar 6, which has a rectangular cross section, can be inserted.

In addition, the punching process is supported by a stripping plate arranged below the punching knife 25. The crossbar 8 is also provided with continuous holes, which, when used as a punch, are

Distance bars 10 or 14 and knife carrier 7. The punched-out pieces of film are thereby conveyed upwards and fall into a collecting tray 9 for punching waste, which is suspended on the crossbar 8 (see Fig. 3). 5

When used as a serrated knife, the counter-pressure bar 15, which is otherwise also rectangular in cross-section, has a slot facing the upper tool. A serrated knife 24 can be inserted into this slot and perforate or cut the film depending on the setting. The cutting process is also initiated by lifting the lifting plate 4 and the film is clamped between the counter-pressure bar 15 and the knife carrier 13. An air supply 23 in the crossbar fills a hose membrane in the knife carrier 13 with air. This hose membrane presses the serrated knife 24 attached to the knife carrier 13 through the slot into the counter-pressure bar 15. The film is severed, the hose membrane is vented and the serrated knife 24 is guided back into the knife carrier 13.

Claims (23)

-1-Protection claims: 1. Separating device (32) for plastic films or similar material for use in a packaging machine (26), comprising at least one upper and at least one lower tool, characterized in that the separating device comprises connecting means (knurled screw 12, pins 19) which allow a quickly detachable connection of cutting devices for different purposes. 2. Separating device according to claim 1, characterized in that the connecting means comprise knurled screws (12). 3. Separating device according to one of claims 1 or 2, characterized in that the connecting means comprise plug pins (19). 4. Separating device according to one of claims 1 to 3, 0 characterized in that the connecting means (knurled screw 12, pins 19) allow the use of the separating device as a punch and as a serrated cutter. 5. Separating device according to one of claims 1 to 4, characterized in that the cutting device, when the separating device is used as a punch, consists of a knife carrier (7) for punching knives, a punching knife (25) and a counter-pressure bar (6) for punching knives corresponding to the punching knife (25). 6. Separating device according to one of claims 1 to 5, characterized in that the cutting device, when the separating device is used as a serrated cutter, consists of a knife carrier (13) for serrated knives, a serrated knife (24) and a counter-pressure bar (15) for serrated knives corresponding to the serrated knife (24). -2- 7. Separating device according to one of claims 5 to 6, characterized in that the counter-pressure bar (6) for punching knives and the counter-pressure bar (15) for serrated knives can be attached with pins (19) to a lifting plate (4) provided with grooves (20). 8. Separating device according to one of claims 5 to 7, characterized in that the lifting plate (4) and the counterpressure bar (6) for punching knives or the counterpressure bar (15) for serrated knives are mounted in guides (5) of the lower tool so as to be movable in the direction of the upper tool. 9. Separating device according to one of claims 1 to 8, characterized in that a pneumatically driven cylinder (2) is provided on the lower tool. 10. Separating device according to one of claims 7 to 9, characterized in that the pneumatically driven cylinder (2) drives a lifting mechanism (3), which in turn actuates the lifting plate (4). 11. Separating device according to claim 10, characterized characterized in that the lifting mechanism (3) is a sliding joint transmission. 12. Separating device according to one of claims 1 to 11, characterized in that tension columns (16) are attached to the 0 lower tool, which protrude beyond the lower tool in the direction of the travel path of the lifting plate (4). 13. Separating device according to one of claims 1 to 12, 5 characterized in that the tension columns (16) have threads at both ends and an area with a larger cross-section approximately in the middle. -3- 14. Separating device according to one of claims 12 or 13, characterized in that clamping pieces (1) can be attached to the tension columns (16). 15. Separating device according to one of claims 12 to 14, characterized in that a crossbar (8) can be attached between the tension columns (16) by means of corresponding lock nuts. 16. Separating device according to claim 15, characterized in that the crossbar (8) is provided with retaining strips (11). 17. Separating device according to one of claims 5 to 16, characterized in that a spacer bar (10) for accommodating a knife carrier (7) for punching knives can be pushed into the holding strips (11) by means of corresponding springs. 18. Separating device according to one of claims 6 to 16, characterized in that a spacer bar (14) for accommodating a knife carrier (13) for serrated knives can be pushed into the holding strips (11) by means of corresponding springs. 19. Separating device according to one of claims 15 to 18, characterized in that the spacer bar (7) and the cross bar contain through holes (22). 20. Separating device according to one of claims 15 to 19, characterized in that a collecting tray (9) for punching waste can be attached to the crossbeam (8). 21. Separating device according to one of claims 15 to 20, characterized in that an air supply is provided in the crossbar (8), which can fill a hose membrane in the knife carrier (13) for serrated knives with air. -4- 22. Packaging machine comprising at least one separating device according to one of claims 1 to 23. Packaging machine according to claim 22, characterized in that the packaging machine is designed as a deep-drawing packaging machine with a forming tool (30) and a sealing tool (31).