EP3613676A1 - Packaging machine with a cutting device with optimised energy consumption - Google Patents

Abstract

A packaging machine for packaging packaging goods by means of a stretchable film is characterized in that a knife device (13) of the packaging machine is connected to a housing (17) surrounding the knife device via a return mechanism (31a) spatially separated from a drive of the knife device. The return mechanism can be activated by transferring the knife device from the rest position (40) to an extended position in which a knife (15) can cut the film from the knife device. With the return mechanism in the activated state, a return force can be exerted on the knife device in the extended position in the direction of the rest position (40). The return force is greater than the return resistance of the knife device in the extended state, by means of which the knife device is held in the extended state without the action of the driving force. The knife device can thus be retrieved, preferably automatically, without the action of the drive.

Description

The invention relates to a packaging machine for packaging packaging goods by means of a stretchable film. The packaging machine comprises a film transport device for feeding film to a product to be packaged and a knife device with a knife for cutting film from the film feed. The knife device can be moved from a rest position into an extended position by a drive with a driving force and the film can be severed by the knife device in the extended position.

From the EP 3 093 244 B1 Such a packaging machine for packaging packaging goods by means of foils is known, in which the foil is cut with a foil cutting device or knife device.

A high-performance stretch film packaging machine can pack more than 35 packaged goods, in particular large tray trays, per minute. With small tray trays, very powerful machines can also achieve more than 40, depending on the package size, even up to 50 packages per minute.

• Das Verpackungsgut wird aufgenommen und gewogen.
• Durch die Folienzuführung wird Folie aus einem Folienvorrat einer Folientransportvorrichtung, insbesondere in Form von Transportriemen, zugeführt und anschließend zum Verpacken eines Verpackungsgutes verwendet. Die Folie wird durch die Messereinrichtung zugeschnitten. Zum Zuschneiden der Folie wird das Messer der Messereinrichtung durch den Antrieb aus der Ruhestellung in die ausgefahrene Stellung überführt.

In particular, the following steps must be carried out in order to pack a product to be packaged:

• The packaged goods are picked up and weighed.
• Through the film feed, film is fed from a film supply to a film transport device, in particular in the form of transport belts, and is then used for packaging a product to be packaged. The film is cut by the knife device. To cut the film, the knife of the knife device is moved from the rest position into the extended position by the drive.

• Das Verpackungsgut wird über einen Hubtisch angehoben und unter der Folie hochgedrückt.
• Die Folie wird mit den seitlichen Schiebern gleichzeitig links und rechts unter das Verpackungsgut geschoben. Ferner wird die Folie mit dem rückwärtigen Schieber von hinten unter das Verpackungsgut geschoben.
• Das Verpackungsgut wird etikettiert und auf das Siegelband geschoben, wobei der vordere Folienteil unter die Packung geschoben wird.
• Die Folie wird unter der Tray-Schale versiegelt und das Verpackungsgut wird ausgegeben.

The film comes in particular from an "endless roll" and is unwound. If a required film length is reached for a packaging process, this film part must be separated from the continuous film. The knife is used to cut the film off the continuous roll. The cutting off of a stretch film in particular is made more difficult by the fact that a stretch film is typically comparatively thin and, due to its stretching properties, easily wraps around the knife without being severed.

• The packaged goods are lifted over a lifting table and pushed up under the film.
• The film is simultaneously pushed left and right under the packaged goods using the side slides. Furthermore, the film is pushed with the rear slider from behind under the packaged goods.
• The packaged goods are labeled and pushed onto the sealing tape, whereby the front film part is pushed under the packaging.
• The film is sealed under the tray and the packaged goods are dispensed.

Typically, during the cutting of the film, a knife of the knife device slides across the film and thereby makes a cut in the film, which leads to a relatively slow cutting process. For a quick cutting process, the knife device is moved to the film by the drive before the cutting process, cuts the film across its entire width, and is moved away from the film after the cutting process.

The use of the drive for the movement of the knife device in both directions towards the film and away from the film requires a quick switchover of the drive and an associated expensive drive and high energy consumption.

In contrast, the object of the present invention is to modify a packaging machine of the type defined at the outset and a packaging method in such a way that the knife device is retrieved, preferably automatically, without the action of the drive.

This object is achieved with regard to the device in a technically particularly simple and surprisingly effective manner by a generic packaging machine of the type defined at the outset, which is characterized in that the knife device is connected to a housing surrounding the knife device via a return mechanism which is spatially separate from the drive. The return mechanism can be activated by transferring the knife device from the rest position into the extended position. The return mechanism in the activated state on the knife device can exert a return force in the extended position in the direction of the rest position. The return force is greater than the return resistance of the knife device in the extended state, by means of which the knife device is held in the extended state without the action of the driving force.

Knives are known from the prior art, for example, which press on the film with a cutting edge the width of the entire film. To cut the film, the knife is pressed onto the film across its entire width using an electric motor or a lifting magnet. After the cutting process, the knife is pulled back with the electric motor or the solenoid. The knife may be returned by spring support. A tension spring is used in particular for spring support. A tension spring can be tensioned and relieved three to five times a minute. Returning the knife with the force of a tension spring is not possible. In addition, the eyes of a tension spring are often prone to breakage. The drive of the knife, in particular in the form of the electric motor or lifting magnet, always acts in both directions, both when the knife is moving in the direction of the film and when the knife is moving away from the film.

In contrast, the return from the extended position to the rest position is carried out by the return mechanism according to the invention against the return resistance of the knife device, the return mechanism not requiring the drive. The return resistance includes all forces without the force of the drive, which act on the knife device in the extended state and counteract a return of the knife device. These forces include in particular friction and inertial forces. The drive can be designed mechanically, electrically or magnetically. The return mechanism enables the drive to act only in the cutting direction of the knife, the knife guide being transferred in the cutting direction from the rest position to the extended position. The drive is then preferably decoupled or switched off. The return mechanism then effects an automatic return of the knife device from the extended position to the rest position against the cutting direction.

An advantageous embodiment of the packaging machine according to the invention is characterized in that the return mechanism has a first elastic element which is in particular indirectly attached to the knife of the knife device. The first elastic element fastened to the knife can be brought into a tense shape by moving the knife device from the rest position into the extended position. This builds up the force required to return the knife device to the rest position. The return then takes place automatically with the relaxation of the elastic element.

A preferred development of this embodiment is characterized in that the first elastic element is designed as a compression spring and is preferably connected to the knife device by means of a rod. Compression springs are characterized by a high load capacity compared to other springs, such as tension springs. They can be used with rapid repetition and with strong spring forces to return the knife guide to the rest position. The rod is preferably passed through the compression spring. A compression spring can be tensioned and relieved up to a hundred times a minute.

In a class of further advantageous embodiments of the invention, the knife device comprises a knife guide, in particular by means of one or more guide plates, preferably in the form of two opposite guide plates. The control of the movement of the knife is considerably improved by a knife guide.

In preferred developments of this class of embodiments, the return mechanism has a second elastic element, in particular in the form of a leaf spring, which is attached at one end to the knife guide and at the other end to the knife. The movement of the knife guide and the knife can be coupled by a second elastic element that connects the knife guide and the knife, so that when the knife moves, the knife guide is automatically moved at least a part. The use of an elastic element enables different settings of the knife and the knife guide relative to one another.

A preferred variant of these further developments is characterized in that the knife can be transferred from a first knife position within the knife guide into a second knife position in which the knife protrudes beyond the knife guide, and with the second elastic element relaxed from the tension while the second elastic element is being tensioned second knife position can be converted back into the first knife position. The knife preferably cuts through the film during the transition from the first knife position to the second knife position. The movement of the knife in the cutting direction is preferably controlled by the drive, the knife guide being held back by a stop. The tension of the second elastic element, in particular the leaf spring, builds up a spring force that is opposite to the cutting direction. After the drive is switched off, this spring force pulls the knife back into the first knife position. By relaxing the first elastic element, the knife in particular can then be returned to the rest position of the knife guide with a driver which takes the knife guide with it.

Further advantageous embodiments of the packaging machine according to the invention are characterized in that the film feed has a film guide element with a cutting gap, which is spaced from the knife device in the rest position by a film feed gap, the knife device, in particular the knife guide, being in contact with the film guide element in the extended position. The film preferably lies against the film guide element and is pressed against the film guide element by the knife device, in particular the knife guide. This will cause a deformation of the Prevents film, especially an elastic film. This enables the film to be cut precisely.

A further development of these embodiments is characterized in that the knife projects through the cutting gap of the film guide element in the extended position of the knife device, in particular the knife guide. In particular, the knife, preferably by the drive, can be transferred from the first knife position to the second knife position in the extended position of the knife guide, reaching through the cutting gap while the knife guide strikes the film guide element. When the knife is transferred from the first knife position to the second knife position, the knife cuts through the film. After cutting through the film, the knife can be automatically returned to the first knife position by the second elastic element, in particular by switching off the drive.

In a further embodiment of the packaging machine according to the invention, it has further elastic elements, in particular in the form of at least one further compression spring and / or at least one further leaf spring. The return forces can thereby be increased and a failure of an elastic element can be compensated for.

A preferred embodiment of the packaging machine is characterized in that the knife guide has at least one link guide, in particular two link guides, for at least one link block formed on the knife, in particular two link blocks. The sliding blocks are preferably on the Housing, which surrounds the knife device, and thus serve to center the knife.

A further development of this embodiment is characterized in that at least one, in particular circular, spacer is arranged on the knife guide between the knife guide and the housing surrounding the knife device, which along the knife device during the transfer of the knife device from the rest position into the extended position can be guided, in particular two spacers are arranged opposite one another on the knife guide. A centering of the knife guide is effected by these spacers.

A particularly preferred variant of this class of embodiments is characterized in that the sliding block is arranged on the housing, extends through the spacer and engages in the sliding block guide of the knife guide, in particular through two sliding block spacers each penetrating a sliding block, each in a sliding block guide Knife guide engages. Then the sliding block or the sliding blocks limit the displacement of the knife guide in the cutting direction.

A further embodiment is characterized in that the film guide element has contact surfaces on the cutting gap, in particular rubber lips, for attachment of the film. Due to the elastic counterforce of the rubber lips, the film can be clamped particularly well between the rubber lips and the knife guide, which presses against the rubber lips in the extended position of the knife guide.

In a further advantageous embodiment of the packaging machine according to the invention, the drive has a pressure magnet, which preferably acts only in the cutting direction of the knife device. The pressure magnet is designed in particular as a lifting magnet, linear magnet and / or electromagnet. The pressure magnet in particular causes a linear movement. However, the force of the pressure magnet only acts in the cutting direction, from the idle state of the knife device to the extended state. It can be switched off after the knife guide and knife have been extended, the return mechanism automatically returning the knife and knife guide to the rest position.

A further preferred embodiment is finally characterized in that the drive and / or the return mechanism - in particular U-shaped - has coupling elements for connection to the knife, which can preferably be inserted into recesses in the knife guide. The U-shaped coupling elements encompass the knife and can then be attached to the knife in a simple manner with bolts guided through the knife. The coupling elements are formed on rods of the pressure magnet, the first elastic element and / or on the second elastic element, in order in each case to establish a mechanical connection with the knife.

Further features and advantages of the invention result from the following detailed description of an embodiment of the invention with reference to the figures of the drawing, which shows details essential to the invention, and from the claims.

The individual features can each be implemented individually or in groups in any combination in variants of the invention.

Fig. 1

einen Längsschnitt durch eine Folienübergabe einer Verpackungsmaschine;

Fig. 2

einen Längsschnitt durch das Folienführungselement und die Messereinrichtung mit einem erfindungsgemäßen Rückholmechanismus in der Ruhestellung und dem Messer in der ersten Messerstellung;

Fig. 3

einen Längsschnitt durch das Folienführungselement und die Messereinrichtung, wobei sich die Messereinrichtung in der ausgefahrenen Stellung und das Messer in der ersten Messerstellung befindet;

Fig. 4

einen Längsschnitt durch das Folienführungselement und die Messereinrichtung, wobei sich die Messereinrichtung in der ausgefahrenen Stellung und das Messer in der zweiten Messerstellung befindet;

Fig. 5

eine Draufsicht auf den Druckmagneten, das Folienführungselement und die Messereinrichtung in der Ruhestellung und mit dem Messer in der ersten Messerstellung;

Fig. 6

zeigt eine Draufsicht auf den Druckmagneten, das Folienführungselement und die Messereinrichtung in der ausgefahrenen Stellung und mit dem Messer in der ersten Messerstellung; und

Fig. 7

eine Draufsicht auf den Druckmagneten, das Folienführungselement und die Messereinrichtung in der ausgefahrenen Stellung, wobei sich das Messer in der zweiten Messerstellung befindet.

In the schematic drawing, an embodiment of the invention is shown, which are explained in more detail in the following description. Show it:

Fig. 1

a longitudinal section through a film transfer of a packaging machine;

Fig. 2

a longitudinal section through the film guide element and the knife device with a return mechanism according to the invention in the rest position and the knife in the first knife position;

Fig. 3

a longitudinal section through the film guide element and the knife device, the knife device being in the extended position and the knife in the first knife position;

Fig. 4

a longitudinal section through the film guide element and the knife device, the knife device being in the extended position and the knife in the second knife position;

Fig. 5

a plan view of the printing magnet, the film guide element and the knife device in the rest position and with the knife in the first knife position;

Fig. 6

shows a plan view of the printing magnet, the film guide element and the knife device in the extended position and with the knife in the first knife position; and

Fig. 7

a plan view of the pressure magnet, the film guide element and the knife device in the extended position, the knife being in the second knife position.

Fig. 1 shows a longitudinal section through a film transfer as part of a packaging machine 10. The packaging machine 10 comprises a film feed 11, through which film from a film supply (not specifically shown in the drawing) is fed to a film transport device 12 . The film is transported by the film transport device 12 to the location of the packaging of a packaged item (not shown). A knife device 13 according to the invention for cutting the film is located between the film feed 11 and the film transport device 12.

The knife device 13 has a knife guide 14 in the form of two opposing guide plates 14a, 14b. A knife 15 is located between the guide plates 14a, 14b . The knife 15 and the knife guide 14 are elastically connected to one another (see Fig. 5 ). Circular spacers 16a, 16b are attached to the guide plates 14a, 14b to maintain the distance between the guide plates and a housing 17 of the knife device 13, which surrounds the knife device 13. The knife 15, the guide plates 14a, 14b and the circular spacers 16a, 16b form a sandwich-like structure.

A film guide element 19 with contact surfaces 20a, 20b is located opposite the knife device 13 (see Fig. 2 ) in the form of rubber lips for attaching the film. A film feed gap 22 for passing the film is formed between the knife device 13 and the film guide element 19. The guide plates 14a, 14b are pressed against the contact surfaces 20a, 20b when the film is cut (see Fig. 3 ). The contact surfaces 20a, 20b are arranged around a cutting gap 23 through which the knife 15 can reach for cutting the film (cf. Fig. 4 ).

A drive 9 in the form of a pressure magnet 25 displaces the knife device 13 via a pressure magnet rod 26 only in one cutting direction 27 towards the film guide element 19. On the pressure magnet rod 26 there is a stop 28 of the pressure magnet rod 26 which bears against the housing 17 of the knife device 13 or against a housing of the pressure magnet 25. The pressure magnet 25 is designed in particular as a lifting magnet, linear magnet or electromagnet, which acts only in the cutting direction 27. The movement of the knife guide 14 in the direction 30 opposite to the cutting direction 27 is carried out by a return mechanism according to the invention (see Fig. 2 ).

Fig. 2 shows a longitudinal section through the film guide element 19 and the knife device 13 with a return mechanism 31a according to the invention . The return mechanism 31a is arranged along the guide plates 14a, 14b offset from the pressure magnet 25 (see FIG. Fig. 5 ). The knife device 13 has the knife guide 14 in the form of the guide plates 14a, 14b and the knife 15 arranged between the guide plates 14a, 14b. The return mechanism 31a includes a first elastic member 32a in the form of a compression spring 33a around a rod 34a of the return mechanism 31a, on which a stop 35a for the compression spring 33a is arranged. The compression spring 33a and the rod 35a are arranged in the housing 17 of the knife device 13. The housing 17 can be formed in one part or in several parts. The rod 34a has at one end 37a a U-shaped coupling element 38a , which is fixedly connected to the knife 15 via a bolt 39a passed through the knife 15.

The knife device 13 is in a rest position 40. The film feed gap 22 is formed between the knife device 13 and the film guide element 19 with the contact surfaces 20a, 20b. With one by the pressure magnet 25 (see Fig. 1 ) caused movement of the knife device 13 in the cutting direction 27 towards the film guide element 19, the compression spring 33a is pressed against the housing 17 and compressed. It then acts with a force on the stop 35a which is opposite to the cutting direction 27. After the pressure magnet 25 has been switched off, the compression spring 33a relaxes, as a result of which the knife device 13 is returned to the rest position 40.

Fig. 3 shows a longitudinal section through the film guide element 19 and the knife device 13, the knife device 13 being in an extended position 41 . The two guide plates 14a, 14b lie against the contact surfaces 20a, 20b of the film guide element 19, bridging the film feed gap 22. The rod 34a of the return mechanism 31a is partially extended and a distance 42 is formed in the cutting direction 27 between the housing 17 of the knife device 13 and the U-shaped coupling element 38a. The knife 15 is in a first knife position 43 arranged within the knife guide 14 between the two guide plates 14a, 14b.

Fig. 4 shows a longitudinal section through the film guide element 19 and the knife device 13, the knife 15 being in a second knife position 44 . The knife guide 14 in the form of the two guide plates 14a, 14b bears against the contact surfaces 20a, 20b of the film guide element 19. The knife 15 between the two guide plates 14a, 14b of the knife guide 14 passes through the cutting gap 23 of the film guide element 19 in the second knife position 44. At the transition from the first knife position 43 (see Fig. 3 ) in the second knife position 44 by the drive of the pressure magnet 25 (see Fig. 1 ) the knife 15 cuts through the film attached to the film guide element 19.

Fig. 5 shows a plan view of the printing magnet 25, the film guide element 19 and the knife device 13 in the rest position 40 (see Fig. 2 ). In particular, the knife 15, the contact surface 20b of the film guide element 19 and the film feed gap 22 are shown. Along the knife 15 there is a return mechanism 31a, 31b on both sides of the pressure magnet 25, each with a first elastic element 32a, 32b in the form of a pressure spring 33a, 33b arranged. Each return mechanism 31a, 31b and the pressure magnet 25 is connected to the respective rod 26, 34a, 34b via a coupling element 38a, 38b, 38c (see Fig. 6 ) and a bolt 39a, 39b, 39c firmly connected to the knife 15. The knife 15 is connected to the knife guide 14 by second elastic elements 45a, 45b in the form of leaf springs 46a, 46b . The leaf springs 46a, 46b are fastened to the knife 15 via coupling elements 38d, 38e of the leaf springs 46a, 46b. The coupling elements 38a - 38e can be When the knife 15 moves in the cutting direction 27 , insert it into recesses 47a, 47b, 47c, 47d, 47e of the knife guide 14. Link blocks 48a, 48b are fastened to the knife 15, which are moved in link guides 49a, 49b of the knife guide 14 and are guided along the housing 17, which surrounds the knife device 13. The sliding blocks 48a, 48b hereby center the knife 15. They further support the return movement of the knife guide 14 after the pressure magnet 25 has been switched off.

Fig. 6 shows a plan view of the printing magnet 25, the film guide element 19 and the knife device 13 in the extended position 41 (see Fig. 3 ). The knife 15 passes through the film feed gap 22 (see Fig. 5 ). The rods 26, 34a, 34b of the return mechanisms 31a, 31b and the pressure magnet 25 are partially extended. The coupling elements 38a-38e of the return mechanisms 31a, 31b and the stop 28 of the pressure magnet 25 are each at a distance from the housing 17 of the knife device 13 in the cutting direction 27.

Fig. 7 shows a plan view of the printing magnet 25, the film guide element 19 and the knife device 13 in the extended position 41 (see Fig. 3 ), the knife 15 in the second knife position 44 (see Fig. 4 ) is located. The coupling elements 38a-38e associated with the return mechanisms 31a, 31b, the pressure magnet 25 and the leaf springs 46a, 46b are inserted into the respective recesses 47a-47e of the knife guide 14.

LIST OF REFERENCE NUMBERS

9

drive

10

packaging machine

11

film feed

12

Film transport device

13

Knife device

14

knife guide

14a, b

guide plates

15

knife

16a, b

spacer

17

casing

19

Film guide element

20a, b

contact surfaces

22

Film feed gap

23

cutting gap

25

pressure solenoid

26

Pressure solenoid rod

27

cutting direction

28

Stop of the pressure magnet

30

opposite direction to cutting direction

31a, b

return mechanism

32a, b

first elastic element

33a, b

compression spring

34a, b

Return mechanism rod

35a

Stop for the compression spring

37

End of the return mechanism rod

38a-e

coupling elements

39a, b, c

bolt

40

rest position

41

extended position

42

distance

43

first knife position

44

second knife position

45a, b

second elastic elements

46a, b

leaf springs

47a-e

Knife guide recesses

48a, b

sliding blocks

49a, b

link guides

Claims (15)

Packaging machine (10) for packaging packaging goods by means of a stretchable film, with a film transport device (12) for feeding film to a packaging item to be packed and a knife device (13) with a knife (15) for cutting film from the film feed (11) The knife device (13) can be transferred from a rest position (40) to an extended position (41) by a drive (9) with a driving force and the film can be severed by the knife device (13) in the extended position (41),
characterized,
that the knife device (13) is connected via a return mechanism (31a) spatially separated from the drive (9) to a housing (17) surrounding the knife device (13), the return mechanism (31a) being connected to the transfer of the knife device (13) from the Rest position (40) in the extended position (41) can be activated, and the return mechanism (31a) in the activated state on the knife device (13) in the extended position (41) a return force in the direction (30) of the rest position (40) can be exercised which is greater than the return resistance of the knife device (13) in the extended state (41), by means of which the knife device (13) is held in the extended state (41) without the action of the driving force. Packaging machine according to claim 1, characterized in that the return mechanism (31a) has a first elastic element (32a) which is in particular indirectly attached to the knife (15) of the knife device (13). Packaging machine according to claim 2, characterized in that the first elastic element (32a) is designed as a compression spring (33a) and is preferably connected to the knife device (13) by means of a rod (34a). Packaging machine according to one of the preceding claims,
characterized in that the knife device (13) has a knife guide (14), in particular by means of one or more guide plates (14a, 14b), preferably in the form of two mutually opposite guide plates (14a, 14b). Packaging machine according to claim 4, characterized in that the return mechanism (31a) has a second elastic element (45a), in particular in the form of a leaf spring (46a), which has one end on the knife guide (14) and the other end on the Knife (15) is attached. Packaging machine according to claim 5, characterized in that the knife (15) can be transferred from a first knife position (43) within the knife guide (14) into a second knife position (44) in which the knife is under tension of the second elastic element (45a) (15) protrudes over the knife guide (14), and with relaxation of the second elastic Elements (45a) can be transferred from the second knife position (44) back into the first knife position (43). Packaging machine according to one of the preceding claims,
characterized in that the film feed (11) has a film guide element (19) with a cutting gap (23), which is spaced from the knife device (13) in the rest position (40) by a film feed gap (22), the knife device (13) in the extended position (41) on the film guide element (19). Packaging machine according to claim 7, characterized in that the knife (15) in the extended position (41) of the knife device (13), in particular the knife guide (14), projects through the cutting gap (23) of the film guide element (19). Packaging machine according to one of claims 2 to 8, characterized in that the packaging machine (10) has further elastic elements (32b, 45b), in particular in the form of at least one further compression spring (33b) and / or at least one further leaf spring (46b). Packaging machine according to one of claims 4 to 9,
characterized in that the knife guide (14) has at least one link guide (49a), in particular two link guides (49a, 49b), for at least one link block (48a) formed on the knife, in particular two link blocks (48a, 48b). Packaging machine according to claim 10, characterized in that at least one, in particular circular, spacer (16a) is arranged on the knife guide (14) between the knife guide (14) and the housing (17) surrounding the knife device (13), which during the transfer the knife device can be guided from the rest position (40) into the extended position (41) along the housing (17) of the knife device (13), in particular two spacers (16a, 16b) being arranged opposite one another on the knife guide (14) , Packaging machine according to claim 11, characterized in that the sliding block (48a, 48b) is arranged on the housing (17), extends through the spacer (16a) and engages in the sliding guide (49a) of the knife guide (14), in particular by two each other opposite spacers (16a, 16b) each penetrate a sliding block (48a, 48b) which engages in each case a sliding guide (49a, 49b) of the knife guide (14). Packaging machine according to one of claims 7 to 12,
characterized in that the film guide element (19) has contact surfaces (20a, 20b) on the cutting gap (23), in particular rubber lips, for the film to be attached. Packaging machine according to one of the preceding claims, characterized in that the drive (9) has a pressure magnet (25) which preferably acts only in the cutting direction (27) of the knife device (13). Packaging machine according to one of the preceding claims, characterized in that the drive (9) and / or the return mechanism (31a, 31b) - in particular U-shaped - coupling elements (38a, 38b) for connection to the knife (15), which preferably can be inserted into recesses (47a, 47b) of the knife guide (14).

Images