EP2602040B1 - Knife assembly - Google Patents

Description

The present invention relates to a knife assembly for slitting web strips of films or tapes with a lower blade shaft and at least one arranged on the lower blade shaft lower blade and an adapter assembly, wherein between the lower blade and the lower blade opposite intermediate piece of the spacer assembly, a cutting groove is formed for the entry of a on a Upper knife shaft arranged upper blade, such that an upper blade cutting edge of the upper blade is guided past a lower blade cutting edge formed on the lower blade, wherein the lower blade cutting edge oppositely disposed axial support edge of the intermediate piece in the longitudinal section profile with a support radius for supporting a film web edge of a by the knife engagement between Upper knife and lower knife sheared web strip is provided.

A knife assembly of the type mentioned is for example from the EP 1 162 043 A1 and is known in particular in a method known as "narrow-cut cutting" method for longitudinal cutting used of films and tapes, wherein the knife assembly is provided according to the desired width of the web strip produced by the longitudinal cutting between each two lower blades of the lower blade shaft with an intermediate piece arrangement, which in the case of EP 1 162 043 A1 Known knife assembly having an intermediate piece which has at its two axial ends in each case a support edge which defines an edge of a cutting groove, which is opposite to the defined by the cutting edge of the adjacent lower blade edge of the cutting groove. In the known blade arrangement, a transition section is formed between the support edges respectively formed at the axial ends of the intermediate piece, which has a transition radius in the longitudinal section profile and extends continuously between the support edges and connects them together.

Deviating from the from the EP 1 162 043 B1 Known knife assembly, which serves to carry out a "Schmalschnittschneidverfahrens", and in which the spacer assembly due to the desired narrow formation of the web strips only has an intermediate piece, which also has a correspondingly small axial length with closely arranged support edges, it is for the production of wider Bahnstreifen common to use spacer assemblies having either an intermediate piece, the axial ends are formed as support edges with a Stützradius and having between the support edges to achieve the desired web width a cylindrical portion as a spacer, or alternatively, a spacer assembly with two at the axial Ends of the spacer assembly disposed intermediate pieces, each having a support edge with a support radius and v by an intermediate cylindrical intermediate piece with each other are linked.

In the spacer assemblies, which have a cylinder portion to achieve a larger web width, it is common to form the transition portion between the support edge and the cylinder portion through a transition cone. Thus, for example, under the URL http://www.dienes.de/Alu-Stahl-NE-Metalle.11.0.html, the website of Dienes Werke for Maschinenteile GmbH & Co. KG as a proven cutting assembly the above-explained spacer assembly with a an axial end of the intermediate piece formed Stützradius, which is transferred by means of a transition cone in a cylinder section. On the website referred to above, the cutting process is also shown in a schematic representation, in which an upper blade engages in the cutting groove formed on the lower blade shaft between the lower blade and the support radius of the intermediate ring assembly, so that a web strip as a result of the knife engagement between to perform a longitudinal section sheared off the lower blade and the upper blade. In the process, a bending line is established in the area of a film web edge of the web strip, which is essentially determined by the geometry of the cross section of the web strip and the material properties of the web strip. Experiments with the cutting assembly illustrated on the above referenced web site have shown that in the illustrated geometry of the spacer assembly having a support radius defining a support rim which merges into a tapered transition portion and which in turn merges into the cylindrical portion of the spacer in the passages between the support edge and the transition section on the one hand and the transition section and the cylinder section on the other hand due to edge formation in the transitions to an at least partially plastic deformation of the film web edge can be pressed due to the shearing against the surface of the intermediate ring assembly. This at least superficial plastic deformation in the region of the film web edge can be particularly with colored or coated surfaces the films or tapes to be processed into web strips lead to local discolorations which render the cut web strips unusable in the region of their film web edges for further processing. In practice, then, the film web edges must be cut out, which means that, for example, the film web edges are not available for punching of partial surfaces of the film, which are used for example as cover surfaces for packaging.

The present invention is therefore based on the object of providing a knife arrangement which makes it possible to produce web strips in a longitudinal cutting process whose film web edges have no plastic deformation in relation to other regions of the web strips and are therefore available for further processing of the web strips and no rejects represent.

This object is achieved by a knife assembly having the features of claim 1.

The knife assembly according to the invention has between the support radius on the support edge of the intermediate ring and a cylinder portion of the intermediate ring on a transition section with a transition radius, wherein the transition radius is greater than the support radius.

The invention is based on the finding that in order to avoid the occurrence of plastic deformation in the region of the film web edge of a web strip, the formation of the bending line of the web strip resulting from the film when shearing off the web strip should be as little as possible due to local collisions with the surface of the intermediate ring arrangement , which lead to the formation of pressure peaks in the material of the web strip to affect. This pressure peaks, which can lead to local plastic deformation of the web strip, namely, arise when the web strip is obstructed during shearing in the free formation of its bending line, so for example against a in the surface of the spacer assembly formed edge abuts. Ideally, this formation of pressure peaks can be prevented by simulating the surface or the surface contour of the spacer assembly in accordance with the bending line of the web strip which results during the shearing process, thus providing the largest possible support of the web strip during the shearing process, without local pressure peaks occurring, however can.

In a preferred embodiment, in the transition between a support edge contour line defined by the support radius and a transition contour line defined by the transition radius, an end point of the support edge contour line and an end point of the transition contour line coincide such that a support edge tangent placed at the endpoint of the support edge contour line and one at the endpoint of the transition contour line placed transition tangent tangent above the intermediate ring include a blunt transition angle.

This ensures that a particularly uniform transition between the contour line of the support edge and the transition contour line is made possible in the region of the foil web edge which is particularly vulnerable to plastic deformation.

It proves to be particularly advantageous if the transition angle is greater than 160 degrees. Particularly preferred is a transition angle greater than 170 degrees, in which the transition is formed evenly.

The complete avoidance of an edge-like transition is achievable if the support edge contour line and the transition contour line are tangentially substantially continuous with each other, so that the transition angle is 180 degrees or at least approximately 180 degrees.

A further improvement of the strip strips producible with the knife assembly becomes possible when an end point of the transition contour line and an end point of the cylinder contour line coincide in addition to the transition between the support edge radius and the transition radius in the transition between the transition contour line defined by the transition radius and a cylinder contour line defined by the cylinder section. such that a transition contour tangent at the end point of the transition contour line and the cylinder contour line above the intermediate ring include an obtuse transition angle.

Thus, not only in the transition between the support radius and the transition radius but also in the transition between the transition radius and the cylinder portion a particularly leveled transition feasible, so that in addition to minimizing the risk of the formation of pressure peaks in the outer edge of the film web and the risk of training Pressure peaks in a region of the film web edge towards the middle of the web strip is possible.

Also, the leveling of the transition between the transition contour line and the cylinder contour line can be increased by appropriate training of a suitable transition angle analogous to the transition between the support edge contour line and the transition contour line to a minimum approximately evenly trained transition.

In the practical application of the knife assembly according to the invention, in particular an embodiment has proved to be a cutting knife arrangement in which the spacer assembly comprises two intermediate pieces which are arranged such that the intermediate pieces are arranged facing each other with their cylindrical portions and each form an axial end of the spacer assembly with their support edges so that, on the one hand, there are matching geometric relationships of the spacer arrangement in the region of both edges of the web strip and, on the other hand, the adjustment of the web width the desired web strip in a simple manner by corresponding axial lengths of the cylinder sections of the intermediate pieces is possible.

Particularly in the case of larger web widths, it is advantageous if a spacer is arranged in the transition between the cylinder sections of the intermediate pieces facing one another, which enables the use of standardized spacers even with different web widths whose axial spacing determines the web width in a simple manner by the separately formed web Spacer, which preferably has a cylinder contour is formed.

In order to be able to make special adjustments to the contour line of the intermediate piece to the bending line of the web strip in individual cases, it is advantageous if the transition portion of the intermediate piece has a transition contour line defined by a plurality of transition radii, which is composed of a plurality of transition sections each defined by a transition radius, wherein coinciding endpoints the transition sections have tangents that include above the intermediate ring an obtuse transition angle.

Such an embodiment of the knife arrangement can prove to be particularly advantageous when web strips are to be produced with the knife assembly, which have no constant thickness or coating and thus have a changing along the web width cross-sectional profile, the corresponding effects on the formation of the bending line Has.

Incidentally, the configurations already described above with respect to the transition between the support edge contour line and the transition contour line on the one hand and the transition contour line and the cylinder contour line on the other hand are also possible for achieving the greatest possible leveling of the transition.

Fig. 1

eine Teildarstellung einer Messeranordnung gemäß dem Stand der Technik mit einem in eine Schneidnut einer Untermesserwelle eingreifenden Obermesser;

Fig. 2

eine in der Darstellung der Fig. 1 entsprechende Teildarstellung einer Ausführungsform der erfindungsgemäßen Messeranordnung mit einem in eine Schneidnut der Untermesserwelle eingreifenden Obermesser und einer Zwischenstückanordnung gemäß;

Fig. 3

eine schematisierte Darstellung der in Fig. 2 dargestellten Zwischenstückanordnung;

Fig. 4

eine weitere Ausführungsform einer Zwischenstückanordnung;

Fig. 5

eine Messeranordnung in Gesamtdarstellung mit jeweils zwischen zwei Untermessern der Untermesserwelle angeordneten Zwischenstückanordnung;

Fig. 6

eine Messeranordnung als Ausschnittmesseranordnung mit einer zwischen zwei Untermessern auf der Untermesserwelle angeordneten Zwischenstückanordnung.

Hereinafter, preferred embodiments of the knife assembly are explained in detail with reference to the drawing. Show it:

Fig. 1

a partial view of a knife assembly according to the prior art with an engaging in a cutting groove of a lower blade shaft upper blade;

Fig. 2

one in the presentation of the Fig. 1 corresponding partial view of an embodiment of the knife assembly according to the invention with an engaging in a cutting groove of the lower blade shaft upper blade and an adapter assembly according to;

Fig. 3

a schematic representation of in Fig. 2 illustrated spacer assembly;

Fig. 4

another embodiment of a spacer assembly;

Fig. 5

a knife assembly in general with arranged between two lower blades of the lower blade shaft spacer assembly;

Fig. 6

a knife assembly as a cutting knife assembly with an intermediate piece arrangement arranged between two lower blades on the lower blade shaft.

Fig. 1 shows a partial view of a knife assembly 10 according to the prior art, which has a arranged on a top blade shaft 11 upper blade 12 which is formed as a circular blade and engages in a cutting groove 13 of a lower blade shaft 14. The cutting groove 13 is bounded by a cutting edge 15 of a lower blade 16 of the lower blade shaft 14 and an axial support edge 17 of an adjacent to the lower blade 16 intermediate piece 18 of a spacer assembly 19.

Fig. 1 shows the knife assembly 10 with a guided for longitudinal cutting of web strip 20 through the knife assembly film web 21, wherein in Fig. 1 only a left film web edge 22 of the web strip 20 is shown. How out Fig. 1 can be seen, the longitudinal cutting of the web strip 20 is characterized in that a cutting edge 23 of the upper blade 12 is guided past the cutting edge 15 of the lower blade 16 and thereby cut from the film web 21 while forming the film web edge 22 of the web strip 20. As further out Fig. 1 can be seen, is due to the cutting process, a deformation of the web strip 20 in the region of the film web edge 22, which corresponds approximately to the course of the bending line, which is adjusted by the action of a single load at the end of a bending beam. As a result of this deformation, the web strip 20 is supported in the region of the film web edge 22 on the support edge 17 of the intermediate piece 18. At the in Fig. 1 illustrated, the prior art corresponding intermediate piece 18 of the support edge 17 at an end point P _s at the end of a support radius R _s defined in its curvature support edge contour line 24 passes directly into a cylinder portion 25 of the intermediate ring 18, which is formed as a horizontal straight cylinder section contour line 26th having. This immediate transition from the support edge contour line 24 into the straight cylinder section contour line 26 causes in the end point P _{s of} the support edge contour line 24, which also represents the transition point to the cylinder section contour line 26, the formation of a force acting as a pressure peak on the film strip 22 reaction force, in particular in the surface region of the film web edge 22nd can cause a plastic deformation of the material of the web strip 20, which in turn can lead to local discoloration of the surface in particular in a coated surface of the film web 21 or a colored surface of the film web 21.

Unlike the in Fig. 1 shown partial view of a prior art knife assembly 10 shows Fig. 2 a Knife assembly 27 having an adapter assembly 28, which according to the invention comprises an intermediate piece 29, which differs from the in Fig. 1 illustrated intermediate piece 18 of the prior art cutting blade assembly 10 is formed. In addition, the in Fig. 2 illustrated knife assembly 27 identical components, as the knife assembly 10 of Fig. 1 , so that according to corresponding reference numerals are used.

The preferably ring-shaped intermediate piece 29 has a support edge 30 with a support edge radius R _s , which defines a support edge contour line 31 in its curvature. Subsequent to the support edge contour line 31, a transition contour line 32 is formed, wherein in the transition between the support edge contour line 31 and the transition contour line 32, an end point of the support edge contour line 31 and an end point of the transition contour line 32 meet at a transition point P _Ü1 , such that one at the end point of the transition contour line 32nd transition transition tangent t _Ü1 and a set to the end of the support edge contour line 31 Stützrandkonturtangente ts include a transition angle α _Ü1 , which is about 160 degrees in the case of the illustrated embodiment. Due to the formation of the transition angle α _Ü1 as an obtuse angle is omitted between the support edge contour line 31 and the transition contour line 32, the formation of a transitional edge, which can lead to the formation of a directed against the surface of the web strip 20 as a pressure peak reaction force. Furthermore, the transition contour line 32 is formed as a convex contour line due to the transition _radius R _Ü1 , so that to a cylindrical portion 33 of the intermediate piece 29, which has a relation to the support edge 30 increased diameter, a continuous increase in the spacer diameter z corresponding to the function of the transition contour line 32.

Fig. 3 shows again in a schematic representation of the contour line of in Fig. 2 shown intermediate piece 29, from the see is that the contour line composed of the support edge contour line 31, the transition contour line 32 and the cylinder contour line 34. As already with reference to the Fig. 2 executed, the two form at each end point of the support edge contour line 31 and the transition contour line 32 in the transition point P _Ü1 tangents t _s and t _Ü1 the transition angle α _Ü1 . Accordingly, in the end points of the transition _contour line 32 and the cylinder _contour line 34 in the transition point P _Ü2, the tangent t _Ü2 and the cylinder _contour line 34 form the transition angle α _Ü2 .

Fig. 4 shows in a schematic representation the contour line of a further intermediate piece 35, which compared to the in Fig. 3 illustrated contour line of the intermediate piece 29 subsequent to the transition contour line 32 in the transition to the cylinder contour line 34 has a further transition contour line 36 having a curvature of the transition contour line 36 determining transition radius R _Ü2 . Between the end points of the transition _contour line 32 and the transition _contour line 36, therefore, tangents _t.sub.U2 and _t.sub.U3 set in the transition point _{P.sub.U3 form} a transition angle _{.alpha..sub.U3} . Between the end points of the transition _contour line 36 and the cylinder _contour line 34, therefore, tangents t _{Ü4 set} in the transition point P _Ü4 and the cylinder _contour line 34 form a further transition angle α _Ü4 .

In the Fig. 4 contour line shown therefore has, in addition to the support radius R _s, the two transition _radii R _Ü1 and R _Ü2 , so that between a support edge 37 of the intermediate piece 35 and a cylinder portion 38 of the intermediate piece 35, a cascade-like enlargement of the spacer diameter z results, the degree of uniformity of respective transition from the support edge contour line 31 to the transition contour line 32 and the transition contour line 32 to the transition contour line 36 and the transition contour line 36 to the cylinder contour line 34 ultimately depends on the choice of the transition angle formed between the respective tangents.

Fig. 5 shows an example of a knife assembly 39 which has on its lower blade shaft 40 between two lower blades 41 an intermediate piece assembly 42, each consisting of an intermediate piece 29 as shown in FIG Fig. 2 and a subsequent to the intermediate piece 29 on the lower blade shaft 40 arranged spacer 43 consists.

Fig. 6 shows in an alternative embodiment, an adapter assembly 44, in which two identically shaped intermediate pieces 29 are arranged with their cylindrical portions against each other, so that the in Fig. 6 illustrated spacer assembly 44 has a symmetrical structure.

Claims (16)

1. A blade arrangement (27, 39) for longitudinally cutting strips (20) of sheet from foils or sheets, comprising a lower blade shaft (40) and at least one lower blade (41) that is arranged on the lower blade shaft and an intermediate piece arrangement (28, 42, 44), wherein a cutting groove (13) is configured between the lower blade and an intermediate piece (29) of the intermediate piece arrangement that is situated oppositely from the lower blade for introducing an upper blade (12) that is arranged on an upper blade shaft (11), in such a manner that an upper blade cutting edge (23) of the upper blade is passed over a lower blade cutting edge (15) that is configured at the lower blade, wherein an axial support rim (30) of the intermediate piece, which is arranged to be situated oppositely from the lower blade cutting edge, in the longitudinal sectional profile is provided with a support radius for supporting a foil sheet rim (22) of a strip of sheet that is cut off by means of the blade introduction between the upper blade and the lower blade,
   characterised in that
   between the support radius R_s at the support rim of the intermediate piece and a cylinder portion (25) of the intermediate piece, a transition portion comprising at least one transition radius R_Ü is configured, wherein the transition radius is larger than the support radius.
2. The blade arrangement according to claim 1,
   characterised in that
   in the transition between a support rim contour line (31) that is defined by the support radius R_s and a transition contour line (32) that is defined by the transition radius R_Ü, an end point of the support rim contour line and an end point of the transition contour line converge in such a manner that a support rim tangent t_s that is drawn to the end point of the support rim contour line and a transition contour tangent t_Ü1 that is drawn to the end point of the transition contour line form an obtuse transition angle α_Ü1 between themselves above the intermediate ring.
3. The blade arrangement according to claim 2,
   characterised in that
   the transition angle α_Ü1 is larger than 160 degree.
4. The blade arrangement according to claim 2,
   characterised in that
   the transition angle α_Ü1 is larger than 170 degree.
5. The blade arrangement according to one of the claims 2 to 4,
   characterised in that
   the support rim contour line (31) and the transition contour line (32) are configured to tangentially merge into each other continuously.
6. The blade arrangement according to one of the preceding claims,
   characterised in that
   in the transition between the transition contour line (32) that is defined by the transition radius and a cylinder contour line (34) that is defined by the cylinder portion (25), an end point of the transition contour line and an end point of the cylinder contour line converge in such a manner that a transition contour tangent t_Ü2 that is drawn to the end point of the transition contour line and the cylinder contour line form an obtuse transition angle α_Ü2 between themselves above the intermediate ring.
7. The blade arrangement according to claim 6,
   characterised in that
   the transition angle α_Ü2 is larger than 160 degree.
8. The blade arrangement according to claim 6,
   characterised in that
   the transition angle α_Ü2 is larger than 170 degree.
9. The blade arrangement according to one of the claims 6 to 8,
   characterised in that
   the transition contour line (32) and the cylinder contour line (34) are configured to tangentially merge into each other continuously.
10. The blade arrangement according to one of the preceding claims,
    characterised in that
    the intermediate piece arrangement (28) comprises two intermediate pieces (29) which are arranged in such a manner that the intermediate pieces are arranged to face each other with their cylinder portions (25), each forming one axial end of the intermediate piece arrangement with their support rims (17).
11. The blade arrangement according to claim 10,
    characterised in that
    in the transition between the cylinder portions of the intermediate pieces (29), which are arranged to face each other, a spacer piece (43) is arranged.
12. The blade arrangement according to claim 11,
    characterised in that
    the spacer piece (43) has the contour of a cylinder.
13. The blade arrangement according to one of the claims 2 to 9,
    characterised in that
    the transition portion has a transition contour line, which is defined by several transition radiuses R_Ü1, R_Ü2 and which is composed of several transition contour lines (32, 36) which are each defined by a transition radius, wherein converging end points of the transition sections have tangents t_Ü2, t_Ü3 that form an obtuse transition angle α_Ü3 between themselves above the intermediate piece (35).
14. The blade arrangement according to claim 13,
    characterised in that
    the transition angle α_Ü3 is larger than 160 degree.
15. The blade arrangement according to claim 13,
    characterised in that
    the transition angle α_Ü3 is larger than 170 degree.
16. The blade arrangement according to one of the claims 13 to 15,
    characterised in that
    the transition contour lines (32, 36) are configured to tangentially merge into one another continuously.

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