EP3718715A1 - Longitudinal cutting with integrated conveyor roller - Google Patents

Abstract

The invention relates to a longitudinal cutting device (18) for a packaging film (19), comprising a plurality of cutting knives (20) for cutting through the packaging film (19) fed to the cutting knives (20) in a film transport direction (F), the plurality of cutting knives (20 ) has a left cutting knife (20a), a right cutting knife (20d) and at least one intermediate cutting knife (20b, 20c) in the film transport direction (F). The longitudinal cutting device (18) comprises at least one feed unit (22) assigned to the intermediate cutting knife (20b, 20c) and designed to transport the packaging film (19), by means of which the packaging film (19) can be conveyed directly at the location of a cutting process in the film transport direction (F) . The invention also relates to a method for severing a packaging film (19) in the film transport direction (F) by means of a longitudinal cutting device (18).

Description

The present invention relates to a slitting device according to claim 1 and a method according to independent claim 14.

On known packaging machines, longitudinal cutting devices are used together with cross-cutting devices for separating produced packaging. Longitudinal cutting devices are designed to feed the packaging film composite fed to them in the film transport direction in the longitudinal direction, i. H. along the film transport direction.

Such a longitudinal cutting device discloses DE 103 59 479 A1 . The longitudinal cutting device disclosed therein comprises a plurality of cutting knives arranged next to one another in the film transport direction, each of which interacts with a counterpressure roller in order to cut through the packaging film conveyed in the film transport direction along the film transport direction. A scissors cut occurs at the respective cutting knives due to the interaction of the respective cutting knives with the respective counter-pressure rollers. The problem with this is that, particularly when cutting through flexible films, ie packaging films with low strength or stiffness, the film material can build up immediately in front of the respective cutting blades. Another problem is that packaging films made of flexible film material can warp due to the scissors-cut effect, which can lead to an unclean cut along the film transport direction.

The object of the invention is to provide a longitudinal cutting device in which the disadvantages described in connection with the prior art can be avoided. Furthermore, the object of the invention is to provide a corresponding method for preventing the disadvantages described in connection with the prior art.

The object of the invention is achieved by means of a longitudinal cutting device according to claim 1 and by means of a method according to independent method claim 14.

Advantageous further developments of the invention are specified in the subclaims.

The invention relates to a longitudinal cutting device for a packaging film, comprising a plurality of cutting knives for cutting through the packaging film fed to the cutting knives in a film transport direction, the plurality of cutting knives in the Film transport direction has a left cutting knife, a right cutting knife and at least one intermediate cutting knife. As a result, in a multi-lane packaging process, the packaging film composite fed to the longitudinal cutting device, consisting of a lower film and an upper film, can be severed by the respective cutting blades along the film transport direction.

According to the invention, the longitudinal cutting device has at least one feed unit assigned to the intermediate cutting knife and designed for transporting the packaging film, by means of which the packaging film can be conveyed in the film transport direction directly at the location of a cutting process. A comparable feed unit can optionally be formed in each case on the other cutting knives of the longitudinal cutting device.

This ensures that, in particular, low-strength packaging film material can be fed tautly to the intermediate cutting knife directly at the location of the cutting process. The film is thus neatly guided through the cutting process, so that the packaging film does not build up in front of the cutting knife.

A feed set for the packaging film is preferably set up on the feed unit in the film transport direction upstream within a film transport plane at a predetermined distance of 1 mm to approx. 50 mm, preferably 4 mm to 20 mm, and / or 5% to 15% of a diameter of the intermediate cutting knife positioned to a cutting edge of the intermediate cutting knife designed for the cutting process. Thus, the packaging film can be drawn in on the feed unit at a short distance directly in front of the cutting knife and transported on in such a way that it can be fed to the cutting edge of the intermediate cutting knife in a tensioned state, which results in a clean longitudinal cut.

One variant provides that, for conveying the packaging film on the feed unit, a force-fit coupling is established between a first conveyor element mounted above the packaging film and a second conveyor element mounted below the packaging film. On the basis of the force-fit coupling between the first and the second conveying element, the packaging film can be clamped in between in such a way that it passes through the cutting process on the cutting knife in a taut state, whereby a clean cut can be reliably produced.

It is advantageous if a contact force aligned orthogonally to a feed plane due to the force-fit coupling can be varied. This makes it possible, in particular, to set a feed force resulting from the contact pressure in the film transport direction for various types of packaging film.

The first conveying element is preferably designed in the form of a disk and has at least one compressible rubber track on the circumference. The packaging film material to be conveyed thus engages particularly well on the feed unit and can be reliably transported along the film transport direction.

A particularly advantageous variant provides that the first conveying element has at least one elastically deformable silicone wheel. A silicone wheel would also be understood here as a silicone tire. During operation, the first conveyor element on the feed unit can be positioned pressed against the conveyor element positioned below the packaging film in such a way that the silicone wheel provided on the first conveyor element is deformed in a predetermined manner in contact with the second conveyor element located below. By means of this deformation, the front part of the feed unit provided for pulling in the packaging film can be set within the film transport plane at a predetermined distance upstream of the cutting edge of the cutting knife in between so that, as described above, the film is drawn in before the packaging film is cut. This enables clean feeding and clean cutting of the packaging film on the cutting knife in between.

A variant provides that the first conveyor element has two spaced apart silicone wheels transversely to the film transport direction, between which the intermediate cutting knife is mounted coaxially. This enables the packaging film to be guided past the feed unit with the aid of the two silicone wheels directly to the side of the cutting knife, as a result of which the packaging film can be better fed to the intermediate cutting knife.

It is advantageous if the intermediate cutting knife is rotatably mounted and the first conveyor element rotatably mounted on a common first shaft. The cutting speed of the cutting knife can thus be set independently of a rotation of the first conveying element. The cutting speed of the cutting knife can thus be adapted outstandingly with regard to the packaging film material fed to the cutting knife. The first shaft is preferably mounted in a height-adjustable manner above the packaging film. The feed unit, in particular a draw-in area formed thereon, can thus be easily adjusted with regard to the packaging film material used.

According to one embodiment, the first conveying element is a counterholder roller and the second conveying element is a drivable feed roller, which are connected via the non-positive coupling and are rotatably supported at the same peripheral speeds. On the basis of the force-fit coupling, the counterholder roll rolls on the feed roll driving it in such a way that the wrapping film drawn in between them is gripped along a contact zone. H. in the film transport direction the foremost part, upstream, is positioned within the film transport plane at a predetermined distance, for example from 0.1 mm to 30 mm, from the cutting edge of the intermediate cutting knife formed for the cutting process.

The cutting knife is preferably mounted so that it can be driven, decoupled from the feed unit, at a variable speed, preferably at a variable speed between 200 to 1000 revolutions per minute. This enables a wide range of flexible film materials to be cut through cleanly.

Preferably, the first conveying element and the second conveying element together form a recess for the intermediate cutting knife. The first conveying element and the second conveying element can interact by means of their frictional coupling in such a way that a section of the packaging film fed to the cutting knife is fixed for the cutting process in a tensioned manner in the recess formed between them. The cutting knife can thus perform a clean longitudinal cut in the film transport direction through the packaging film material fed tautly to it.

The invention also relates to a packaging machine, preferably a thermoforming packaging machine, with a longitudinal cutting device of the type described above and with a separate film transport device, for example in the form of clamp chains guided laterally on the machine frame, which are designed to cut the packaging film along a large number of times according to a machine cycle of the packaging machine To promote workstations of the packaging machine, an operation of the feed unit of the longitudinal cutting device being coupled to an operation of the film transport device of the packaging machine. The feed unit used on the longitudinal cutting device according to the invention can thus be operated synchronously with the film transport device of the packaging machine.

Preferably, all of the cutting knives of the longitudinal cutting device are each equipped with a feed unit, as was described above in connection with the intermediate cutting knife. Nonetheless, it can be provided that the outermost cutting knives in the film transport direction, i. H. the left and right cutting knives, which are positioned on a packaging machine next to the side clamp chains of the packaging machine that hold the film material taut, do not require a separate feed unit in order to make a clean cut through the packaging film material.

The invention also relates to a method for severing a packaging film in the film transport direction by means of a longitudinal cutting device which has a left cutting knife, a right cutting knife and at least one intermediate cutting knife in the film transport direction. According to the invention, a feed unit of the longitudinal cutting device positioned on the intermediate cutting knife pulls in the packaging film for a cutting operation and feeds the packaging film directly to the intermediate cutting knife of the longitudinal cutting device. With the aid of the feed unit used according to the invention, it is achieved directly at the location of the intermediate cutting knife that the packaging film is fed tautly to a cutting edge formed on the cutting knife, without the possibility of jamming, so that the cutting knife consequently cuts the packaging film material cleanly in the film transport direction.

It is particularly advantageous if the packaging film is drawn in at a draw-in of the feed unit before the packaging film is fed to a cutting edge of the intermediate cutting knife located directly downstream within a film transport plane in the film transport direction. This means that the feed unit is already drawn in, i.e. H. upstream in the film transport direction, the cutting of the packaging film at the intermediate cutting knife takes place, whereby a build-up of the packaging film material on the cutting knife can be avoided. Consequently, the packaging film is neatly guided through the cutting process and is consequently severed particularly neatly in the film transport direction.

Figur 1

eine Tiefziehverpackungsmaschine mit einer Längsschneideeinrichtung zum Durchtrennen einer Verpackungsfolie in Folientransportrichtung;

Figur 2

eine schematische Draufsicht eines Ausschnitts der in Fig. 1 gezeigten Tiefziehverpackungsmaschine;

Figur 3

eine perspektivische Darstellung einer Längsschneideeinrichtung;

Figur 4

eine vergrößerte Perspektivdarstellung eines Teils der in Fig. 3 gezeigten Längsschneideeinrichtung;

Figur 5

eine schematische Schnittdarstellung im Bereich eines Schneidmessers der Längsschneideeinrichtung; und

Figur 6

eine schematische Darstellung einer an der Vorschubeinheit ausgebildeten kraftschlüssigen Kopplung.

Advantageous exemplary embodiments of the invention are explained in more detail with reference to the figures. Show it:

Figure 1

a thermoforming packaging machine with a longitudinal cutting device for severing a packaging film in the film transport direction;

Figure 2

a schematic plan view of a section of the in Fig. 1 shown thermoforming packaging machine;

Figure 3

a perspective view of a longitudinal cutting device;

Figure 4

an enlarged perspective view of part of the FIG Fig. 3 shown slitter;

Figure 5

a schematic sectional view in the area of a cutting knife of the longitudinal cutting device; and

Figure 6

a schematic representation of a non-positive coupling formed on the feed unit.

Fig. 1 shows a thermoforming packaging machine 1. In the film transport direction F, the thermoforming packaging machine 1 comprises, one behind the other, an unwinding unit 2 for a lower film 3, a forming station 4 for forming packaging trays 5, an insertion path 6, along which products 7 are placed in the shaped packaging trays 5, a sealing station 8 for Closing the packaging trays 5 with an upper film 9, a cutting station 10 for separating finished packaging 11 as well as a discharge belt 12 positioned at the exit of the thermoforming packaging machine 1 for the removal of finished packaging 11. All workstations of the thermoforming packaging machine 1 are in Fig. 1 attached to a machine frame 13.

Fig. 2 FIG. 14 shows sections of the thermoforming packaging machine 1 from FIG Fig. 1 . In the film transport direction F, a film transport device 14 is provided on the machine frame 13 of the thermoforming packaging machine 1. The film transport device 14 comprises to the left and right of the machine frame 13 chain clips 15a, 15b, guided in the film transport direction F, for gripping and conveying the lower film 3 up to the sealing station 8 and for gripping and transporting the composite made at the sealing station 8 of the lower film 3 with the one sealed thereon Upper film 9.

According to Fig. 2 the manufacturing process takes place on the thermoforming packaging machine 1 in multiple lanes. Fig. 2 shows that work is being carried out along three tracks 16a, 16b, 16c. In the film transport direction F, the sealed packagings 11 are accordingly fed to the cutting station 10 in three lanes following the sealing station 8. The cutting station 10 has a transverse cutting device 17 and a longitudinal cutting device 18 one behind the other in the film transport direction F. The cross-cutting device 17 is designed to consist of the packaging film 19 fed to the cross-cutting device 17, transversely to the film transport direction F from the lower film 3 and the upper film 9 sealed therewith, to be severed between the packaging 11 produced. The longitudinal cutting device 18 positioned behind the cross-cutting device 17 in the film transport direction F is designed to cut the packaging film 19 in the film transport direction F, ie in the longitudinal direction of the manufacturing process, so that finished, isolated packs 11 are present after the cutting station 10.

Fig. 3 shows the longitudinal cutting device 18 in an isolated perspective view. The longitudinal cutting device 18 comprises a multiplicity of cutting knives 20 which are mounted coaxially transversely to the film transport direction F for cutting through the packaging film 19. According to Fig. 3 a left cutting knife 20a, a right cutting knife 20d and two intermediate cutting knives 20b, 20c are positioned coaxially on a first shaft 21 in the film transport direction F.

Also shows Fig. 3 that the respective cutting knives 20 are each assigned a feed unit 22 directly. The respective feed units 22 are designed for transporting the packaging film 19 and, in particular, are mounted in such a way that the packaging film 19 can be conveyed thereon directly at the location of the respective cutting knife 20 in the film transport direction F. Also shows Fig. 3 that close to the left and right cutting knife 20a, 20d in the film transport direction F, the side clamp chains 15a, 15b are mounted.

Fig. 4 shows an enlarged section of the in Fig. 3 shown longitudinal cutting device 18. According to Fig. 4 the respective feed units 22 have an infeed 23 at which the packaging film 19 is drawn in before the cutting process, but immediately in front of the respective cutting knife 20. It is thereby achieved that the packaging film 19 drawn in by means of the feed units 22 runs through the respective cutting process under tension in the region of the respective cutting knife 20, so that it can be severed cleanly in the film transport direction F.

Fig. 4 shows that the feed units 22 each have a first conveyor element 24 mounted above the packaging film 19 (not shown) and a second conveyor element 25 mounted below the packaging film 19. On the feed units 22, the respective first conveying element 24 has two adjacent silicone wheels 36, between which the respective cutting knife 20 is mounted coaxially.

The first wave 21 off Fig. 4 , along which the cutting knives 20 and the first conveyor elements 24 assigned to them are mounted coaxially, can be adjusted in height by means of an adjusting mechanism 26. The respective first conveyor elements 24 of the feed units 22 can thereby rest pressed against the associated second conveyor elements 25 positioned underneath in such a way that they clamp the packaging film 19 between them. As a result, a non-positive coupling 27 between the first and second conveying elements 24, 25 pressed against one another is produced at the feed units 22. On the basis of the height-adjustable mounting of the first shaft 21, a contact force K oriented orthogonally to a film transport plane E of the packaging film 19 can be varied in the region of the respective frictional coupling 27. By pressing the respective first conveying elements 24 onto the second conveying elements 25 positioned below, a conveying zone 28 for the packaging film 19 is formed in the respective intermediate area. At the conveying zones 28, the respective feeder 23 is located upstream in the film transport direction F within the film transport plane E to the cutting knife 20 in order to pull the packaging film 19 into the feed unit 22 before the cutting knife 20 plunges into the packaging film 19.

The respective first conveyor elements 24 from Fig. 4 are designed as counterholder rollers 29. The counterholder rollers 29 are rotatably mounted on a first shaft 21 transversely to the film transport direction F coaxially. On the respective feed unit 22, the respective second conveyor elements 25 form driven feed rollers 35 that are non-rotatably mounted on the second shaft 30, the first and second conveyor elements 24, 25 being able to be driven at the same circumferential speeds by means of the non-positive coupling 27. The respective first conveying elements 24 are rotatably mounted on the first shaft 21, so that the feed units 22 are decoupled from the operation of the cutting knives 20. This makes it possible to drive the cutting knife 20 at a variable speed.

Fig. 5 shows a schematic sectional illustration of the feed unit 22 on the intermediate cutting knife 20b. The first conveying element 24 and the second conveying element 25 together form a recess 31 for the intermediate cutting knife 20b. In a lower region of the recess 31, below the packaging film 19, the cutting knife 20b protrudes into the second conveying element 25 of the feed unit 22 in order to cut through the packaging film 19. The view from Fig. 5 could just as well refer to the feed unit 22 of another cutting knife 20 of the longitudinal cutting device 18.

Fig. 6 shows a schematic arrangement of the feed unit 22 transversely to the film transport direction F. Fig. 6 shows that a front part of the intake 23 on the feed unit 22 in the film transport direction F upstream, within the film transport plane E in a predetermined Distance 32 is positioned from a cutting edge 33 of the intermediate cutting knife 20b, which is designed for the cutting process. The distance 32 can be varied in that the pressing force K of the first conveyor element 24, which is made of deformable material at least in the contact area, is adjusted on the second conveyor element 25 positioned below it. Setting the distance 32 at the infeed 23 of the feed unit 22 enables the packaging film 19 to be drawn in in the film transport direction F upstream of the cutting edge 33 for the cutting process before the packaging film 19 is severed with the aid of the cutting knife 20b. The packaging film 19 can thus be neatly fed to the cutting knife 20b.

The principle according to the invention can be used for each of the coaxially arranged cutting knives 20a, 20b, 20c, 20d. Preferably, however, the feed unit 22 used in the invention is used on the intermediate, ie not positioned completely outside, cutting knives 20b, 20c in order to cleanly feed the packaging film 19 to the cutting process in their area. It would thus be conceivable that the outer cutting knives, ie the one in Fig. 3 The left and right cutting knives 20a, 20d shown can do without a feed unit 22 because the staple chains 15a, 15b of the thermoforming packaging machine 1 already pass them in the film transport direction F, so that the packaging film can be fed tautly to the outer cutting knives.

Claims (15)

Longitudinal cutting device (18) for a packaging film (19), comprising a plurality of cutting knives (20) for cutting through the packaging film (19) fed to the cutting knives (20) in a film transport direction (F), the plurality of cutting knives (20) in the film transport direction (F) has a left cutting knife (20a), a right cutting knife (20d) and at least one intermediate cutting knife (20b, 20c), characterized in that
the longitudinal cutting device (18) has at least one feed unit (22) assigned to the intermediate cutting knife (20b, 20c) and designed to transport the packaging film (19), by means of which the packaging film (19) can be conveyed directly at the location of a cutting process in the film transport direction (F) . Slitting device according to Claim 1, characterized in that a feed (23) set for the packaging film (19) on the feed unit (22) in the film transport direction (F) upstream, within a film transport plane (E) at a predetermined distance (32) of 1 mm up to 50 mm or 5% to 15% of the diameter of the intermediate cutting knife (20b, 20c) is positioned in relation to a cutting edge (33) of the intermediate cutting knife (20b, 20c) designed for the cutting process. Slitting device according to claim 1 or 2, characterized in that for conveying the packaging film (19) on the feed unit (22) there is a force-fit coupling (27) between a first conveyor element (24) mounted above the packaging film (19) and a second conveyor element (24) below the packaging film (19) mounted conveyor element (25) is made. Slitting device according to Claim 3, characterized in that a pressure force (K) aligned orthogonally to a film transport plane (E) by the force-fit coupling (27) can be varied. Slitting device according to one of Claims 3 to 4, characterized in that the first conveyor element (24) is disk-shaped and has at least one compressible rubber track (34) around the circumference. Longitudinal cutting device according to one of Claims 3 to 5, characterized in that the first conveyor element (24) has at least one elastically deformable silicone wheel (S). Slitting device according to claim 6, characterized in that the first conveyor element (24) has two spaced apart silicone wheels (S) transversely to the film transport direction (F), between which the intermediate cutting knife (20b, 20c) is mounted coaxially. Longitudinal cutting device according to one of Claims 3 to 7, characterized in that the intermediate cutting knife (20b, 20c) are rotatably mounted and the first conveyor element (24) rotatably mounted on a common first shaft (21). Slitting device according to Claim 8, characterized in that the first shaft (21) is mounted in a height-adjustable manner above the packaging film (19). Slitting device according to one of claims 3 to 9, characterized in that the first conveyor element (24) is a counter-holder roller (29) and the second conveyor element (25) is a drivable feed roller (35) which, via the non-positive coupling (27), operate at the same peripheral speeds (v) are rotatably mounted. Longitudinal cutting device according to one of the preceding claims, characterized in that the intermediate cutting knife (20b, 20c) is mounted decoupled from the feed unit (22) and can be driven at a variable speed. Slitting device according to one of Claims 3 to 11, characterized in that the first conveyor element (24) and the second conveyor element (25) together form a recess (31) for the intermediate cutting knife (20b, 20c). Packaging machine, which is preferably designed in the form of a thermoforming packaging machine (1), with a longitudinal cutting device (18) according to one of the preceding claims and with a separate film transport device (14), which is designed to move along the packaging film (19) according to a machine cycle of the packaging machine to convey a plurality of work stations of the packaging machine, operation of the feed unit (22) of the longitudinal cutting device (18) being coupled to operation of the film transport device (14) of the packaging machine. Method for severing a packaging film (19) in the film transport direction (F) by means of a longitudinal cutting device (18) which has a left cutting knife (20a), a right cutting knife (20d) and at least one intermediate cutting knife (20b, 20c) in the film transport direction (F) ,
characterized in that
a feed unit (22) of the longitudinal cutting device (18) positioned on the intermediate cutting knife (20b, 20c) pulls in the packaging film (19) for a cutting process and feeds the packaging film (19) directly to the intermediate cutting knife (20b, 20c) of the longitudinal cutting device (18). A method according to claim 14, characterized in that the packaging film (19) is drawn in at a feed unit (23) of the feed unit (22) before the packaging film (19) is attached to the feed unit (23) directly in the film transport direction (F) within a film transport plane (E ) downstream cutting edge (33) of the intermediate cutting knife (20b, 20c) is fed.

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