Perforating knife with crimping surface

Abstract

The invention relates to a perforating blade 1 for perforating at least one layer of a substrate to be processed into a printed product. The invention is based on the objective of providing a solution that improves the interlinking effect between the perforated substrate layers. This objective is achieved by a device according to claim 1. The device according to the invention comprises a perforating blade 1 in which a crimping surface 5 adjoins the base 4 of the perforating tip 3 on at least one side.

Description

[0001] The invention relates to a circular perforating blade for perforating at least one

[0002] A layer of a printing material to be processed into a printed product, wherein the perforating blade has a plurality of perforating elements on its circumference, wherein each perforating element comprises at least one perforating tip extending radially from an outer radius to at least one base point located on a first radius, and wherein a crimping surface adjoins the base point of the perforating tip on at least one side of the perforating tip. Furthermore, the invention relates to a method for operating a perforating blade.

[0003] In the folding units of web-fed printing presses or in various folding or post-processing machines, perforating devices are used to perforate at least one layer of the substrate, which typically moves in one direction of transport. If the substrate is perforated transversely to the transport direction, so-called transverse perforations are used, in which the actual perforating blade comprises a metal strip with at least one edge formed with perforating teeth.

[0004] If the substrate is perforated in the transport direction, so-called longitudinal perforations are used. The perforating blade is typically designed as a circular blade with perforating teeth on at least part of its peripheral surface. These perforating teeth usually consist of sharp teeth that pierce at least one layer of the substrate to be perforated. For this purpose, the perforating blade, which is usually driven by rotation, interacts with a counterblade, which has either a groove or a relatively soft and elastic surface, at least in part, and serves as a counterblade for the substrate to be perforated.

[0005] A large number of perforating knives are known from the prior art, which have a large number of pointed perforating teeth on at least part of their effective surface, in the case of circular knives this is the outer circumferential surface.

[0006] EP 0 197 190 A2 discloses a device for punching sheets or webs. It comprises a punching wheel with teeth, each tooth being the size of the section to be punched out and having a nose located at the rear end of the tooth in the circumferential direction. The nose is designed so that both the leading and trailing edges of the tooth pierce the web at approximately the same time. The tooth plunges into the web along its entire circumferential length and ejects the punched-out section.

[0007] DE 807 622 C discloses a device for carrying out a stapling operation in which tongues are punched out with a punching device, wherein the punching device may comprise, inter alia, a punching wheel with a plurality of punching teeth.

[0008] US 4,166,613 A discloses a perforating mechanism with a punching blade for punching and collecting reusable paper scraps from a web. The punching blade comprises several teeth with a leading cutting edge and a trailing projection forming a second cutting edge. Each tooth punches and ejects a rectangular piece from the web, with the trailing cutting edge penetrating the web before the piece is completely punched out along its long sides.

[0009] Since the perforating teeth of some perforating knives known from the prior art essentially have the shape of a triangle, the perforation intensity can be varied by changing the penetration depth of the perforating teeth into the substrate to be perforated.

[0010] Furthermore, it is known from the prior art that by perforating a plurality of superimposed printing substrate layers, these are interlinked by the joint piercing, so that the individual printing substrate layers are fixed in their position relative to one another. This effect is used, for example, in the production of book blocks, but is not limited to this, so that the respective printing substrate layers are fixed to one another, allowing, for example, a consistently large margin around the text page when the individual book blocks are combined to form a book.

[0011] However, the interlinking effect of perforating knives known from the state of the art depends, among other things, on the type of paper, the number of substrate layers to be interlinked and the geometry of the perforating teeth.

[0012] The invention is therefore based on the object of creating a solution with which the interlinking effect between the perforated printing material layers can be improved.

[0013] This object is achieved by a device according to claim 1.

[0014] Such a perforating knife has the advantage that at least after perforation, i.e. after the printing material layers have been pierced by each perforating tip, which creates a small bead in each printing material layer, which fixes the individual printing material layers to one another, the superimposed printing material layers are pressed together again with the crimping surface immediately after the perforation process, which significantly increases the intensity of the interlinking and offers the advantage that the intensity of the interlinking can be better varied in interaction with the abutment due to the inclination of the crimping surface to a concentric circle described by the first radius.

[0015] A perforating blade according to the invention thus has a crimping surface downstream of the perforating tip, viewed in the direction of rotation. This crimping surface has a limited extent, typically 2 to 10 mm, viewed in the circumferential direction. This allows the area around a perforation hole to be compressed further, so that the beads of the respective printing material layers interlock or "felt" with each other even more intensively.

[0016] Preferred developments of the inventions emerge from the dependent claims and the following description. Various embodiments of the invention are explained in more detail with reference to the drawings, without being limited thereto. Fig. 1, 2 , 4-6 possible designs of perforating knives according to the invention. Fig. 1 an exemplary perforating knife Fig. 2 an exemplary perforating element of the perforating knife in a detailed view Fig. 3 a possible design of a perforating element Fig. 4 a possible design of a perforating element in which the crimping surface has an angle of inclination Fig. 5 a possible design of a perforating element with crimping surfaces on both sides of the perforating tip Fig. 6 a possible design of a perforating element with two perforating tips

[0017] Fig. 1shows a perforating blade 1 according to the invention, which is designed as a circular blade. Such a perforating blade 1 is used for perforating at least one layer of a printing substrate to be processed into a printed product. For this purpose, the perforating blade 1 is accommodated in a rotationally driven holder and is operatively connected to a rotating abutment (not shown). The printing substrate to be perforated is supported by the rotating abutment, so that the perforating tips 3 can pierce and thus perforate the printing substrate to be perforated.

[0018] The Fig. 1The perforating blade 1 shown is usually made of sheet steel and has a thickness of typically 0.5 millimeters to a maximum of 2 millimeters. It is typically produced by laser cutting and / or grinding. The perforating tips 3 can also be positioned toward the plane of the drawing, although this is irrelevant to the present invention. The perforating blade 1 can be hardened or tempered in its entirety; however, it is also possible to harden or temper only the perforating tips 3 or the perforating tips 3 and the crimping surfaces 5.

[0019] The perforating blade 1 has a plurality of perforating elements 2 on its circumference. If a printing material or a pre-product made from it, which usually consists of several layers of printing material lying one above the other, is to be perforated only on a first partial length and not perforated on a second partial length, it is also possible, although in Fig. 1not shown that a perforating knife 1 has such perforating elements 2 only on one or more first partial sections and has no perforating elements 2 on one or more second partial sections.

[0020] The Fig. 1 The perforating knife 1 shown has a defined circular shape, wherein the outer envelope is defined by a defined outer radius Ra.

[0021] Furthermore, due to the geometry of the perforating elements 2, the Fig. 1 The perforating blade 1 shown has a defined direction of rotation 7 to ensure a particularly advantageous effect during operation. The distance between the perforation elements 2 in the circumferential direction of the outer circle determines the spacing of the perforations.

[0022] Fig. 2 shows the detailed view of the Fig. 1 area of a perforating element 2 shown as X on an enlarged scale.

[0023] Fig. 2thus shows in enlarged form an exemplary embodiment of a perforating element 2, wherein the Fig. 2 The perforating element 2 shown comprises a perforating tip 3 with a base point 4 and an adjoining crimping surface 5, wherein the crimping surface 5 adjoins the base point 4 of the perforating tip 3.

[0024] Although in Fig. 2 by way of example only shows an embodiment of a perforating element 2 with only one perforating tip 3 and one crimping surface 5, embodiments with a plurality of perforating tips 3 and / or a plurality of crimping surfaces 5 are also possible.

[0025] Fig. 3 shows a further exemplary embodiment of a perforating element 2, as well as further details on the geometry of a perforating element 2.

[0026] As from Fig. 3As can be seen, the perforating tip 3, that is to say the part of the perforating element 2 which, during use, pierces into the at least one printing material layer or preferably pierces and thus perforates all printing material layers to be perforated, extends radially from the outer radius Ra to a base point 4 arranged on a first radius R1. The difference between the outer radius Ra and the first radius R1 thus defines the height of the perforating tip 3, which is usually in a range from approximately 1 millimeter to approximately 10 millimeters.

[0027] In the Fig. 3 In the example shown, a crimping surface 5 borders one side of the perforating tip 3, namely on the side of the perforating tip 3 facing away from the direction of rotation 7, which crimping surface 5 directly adjoins the base point 4 of the perforating tip 3.

[0028] Although Fig. 3shows an embodiment with only one crimping surface 5 adjacent to the perforating tip 3, it is also possible for several crimping surfaces 5 to adjoin a perforating tip 3, as shown and described below.

[0029] Such a crimping surface 5 has a limited extension in the circumferential direction, which is usually approximately between 2 and 10 millimeters.

[0030] Fig. 3shows a non-inventive embodiment of a perforating element 2, in which the crimping surface 5 extends along the first radius R1, i.e., the crimping surface 5 has the shape of a circular segment defined by the first radius R1, so that when the perforating blade 1 is used in a longitudinal perforating device, each crimping surface 5, with a corresponding setting depth, can roll on the printing material (not shown) to be perforated after the printing material has been pierced by the perforating tips 3. Thus, with a corresponding setting depth, the printing material layers already interlinked with one another or into one another by the perforation can be pressed together again after being pierced by each crimping surface 5 and pressed against the abutment (not shown) required for the perforating process, thereby significantly increasing the interlinking effect, which is also known as "felting" among bookbinders.

[0031] Fig. 4 shows a further exemplary embodiment of a perforating element 2, as well as details of an alternative geometry of a perforating element 2.

[0032] As well as from Fig. 4 As can be seen, here too the perforating tip 3, that is to say the part of the perforating element 2 which, when in use, pierces into the at least one printing material layer or preferably pierces and thus perforates all of the printing material layers to be perforated, extends radially from the outer radius Ra to a base point 4 arranged on a first radius R1. The difference between the outer radius Ra and the first radius R1 thus defines the height of the perforating tip 3, which in this variant is also usually in a range of approximately 1 millimeter to approximately 10 millimeters.

[0033] Even with the Fig. 4In the example shown, a crimping surface 5 borders one side of the perforating tip 3, namely on the side of the perforating tip 3 facing away from the direction of rotation 7, which crimping surface 5 directly adjoins the base point 4 of the perforating tip 3.

[0034] Although Fig. 4 While the embodiment shown has only one crimping surface 5 adjacent to the perforating tip 3, it is also possible for a perforating tip 3 to have multiple crimping surfaces 5 adjacent to it, as shown and described below. Such a crimping surface 5 has a limited circumferential extension, which is generally approximately between 2 and 10 millimeters.

[0035] Fig. 4However, it shows an alternative embodiment of a perforating element 2 according to the invention, in which the crimping surface 5 has an angle of inclination α to the circle 6 defined by the first radius R1. According to the invention, the angle of inclination can be defined between the tangent (not shown in the drawing) adjacent to the circle 6 at the base point 4 of the perforating tip 3 and the crimping surface.

[0036] In contrast to the Fig. 3 In the illustrated embodiment of a perforating element 2, the crimping surface 5 is thus not defined by the circle 6 defined by the first radius R1 or a circular segment contained therein, but rather has an inclination relative thereto. The angle of inclination α used therein lies in a range from 1° to approximately 45°, preferably in a range from 10° to 30°.

[0037] By changing the inclination of the crimping surface 5 to the circle 6 or tangents applied thereto, the contact pressure and thus the crimping as well as the resulting interlinking or matting can be adjusted more finely by changing the position of the perforating knife 1 to the abutment.

[0038] As in the Figures 2 to 4 , as well as in the following Figures 5 and 6 As shown, the transition between the perforating tip 3 and the crimping surface 5 can be rounded, as this is advantageous both in terms of fatigue strength and manufacturing. The radii used here are typically in a range of approximately 0.1 millimeters to approximately 5 millimeters.

[0039] The Figures 2 to 4The embodiments of perforating elements 2 shown have a common feature that each perforating element 2 has a perforating tip 3 on its leading side, as seen in the direction of rotation 7, which is adjoined by a crimping surface 5 on the side opposite the direction of rotation 7, or in other words, on the side facing away from the direction of rotation 7. Such a configuration does have the advantage that after the superimposed printing material layers have been perforated, they are crimped in the sense of being pressed together by the subsequent crimping surface 5, which is advantageous for the interlinking of the printing material layers to one another.

[0040] However, such perforating knives 1 require a fixed direction of rotation 7, which must be observed when installing the perforating knife 1 in a corresponding perforating device.

[0041] In order to avoid a special required direction of rotation 7, alternative embodiments with a symmetrical design of the perforating element 2 are advantageous.

[0042] Fig. 5 shows an exemplary embodiment of a perforating element 2 according to the invention, which is arranged on each perforating element 2 in the direction of rotation 7 (see Fig. 1 ) seen leading and trailing side of the perforating element 2 each has a perforating tip 3. The Fig. 5 The perforating element 2 of the perforating knife 1 shown thus points in the direction of rotation 7 (see Fig. 1 ) has a first perforating tip 3-1, a first crimping surface 5-1 adjacent thereto, a second crimping surface 5-2 and a second perforating tip 3-2 adjacent thereto and is thus independent of the direction of rotation.

[0043] Although in Fig. 5an embodiment is shown in which both the first crimping surface 5-1 and the second crimping surface 5-2 have an inclination relative to the circle 6 described by the first radius R1 or tangents applied thereto, as under Fig. 4 described, it is also possible, although not shown in the drawing, that the first and / or the second crimping surface 5-1, 5-2 have the shape of a circular arc segment, which is defined by the radius R1, as in the description of the in Fig. 3 illustrated embodiment. However, such embodiments are not in accordance with the invention.

[0044] Fig. 6 shows a further exemplary embodiment of a perforating element 2 according to the invention, which is arranged on each perforating element 2 in the direction of rotation 7 (see Fig. 1 ) seen leading and trailing side of the perforating element 2 each has a crimping surface 5. The Fig. 6The perforating element 2 of the perforating knife 1 shown thus points in the direction of rotation 7 (see Fig. 1 ) has a first crimping surface 5-1, an adjacent perforating tip 3 and an adjacent second crimping surface 5-2 and is therefore also independent of the direction of rotation.

[0045] Although in Fig. 6 an embodiment is shown in which both the first crimping surface 5-1 and the second crimping surface 5-2 have an inclination relative to the circle 6 described by the first radius R1 or tangents applied thereto, as under Fig. 4 described, it is also possible, although not shown in the drawing, that the first and / or the second crimping surface 5-1, 5-2 have the shape of a circular arc segment, which is defined by the radius R1, as in the description of the in Fig. 3 illustrated embodiment. However, such embodiments are not in accordance with the invention.

[0046] Although none of the Fig. 1 to 6 shown graphically, it is also possible to use a perforating knife 1 with different designs of the perforating elements 2, as in the Fig. 3 to 6 shown and described, so that in a perforating knife 1 according to the invention not only a single embodiment of a perforating element 2 is necessarily used.

[0047] Although not shown in any of the figures, it is also possible to create a recess between a perforating tip 3 and the adjacent crimping surface 5, with respect to the area of the crimping surface 5 having the first radius R1, comparable to an undercut. This means that in the area of the base point 4 of the perforating tip 3, a recess is created with respect to the area of the crimping surface 5 having the largest radius, which corresponds to the first radius R1. Such a recess has a width of approximately 0.1 millimeters to approximately one millimeter in the circumferential direction of the circle 6 described by the first radius R1, depending on the manufacturing process.

[0048] The crimping surface 5 thus still borders on the respective adjacent perforating tip 3, but this may allow for easier processing of the crimping surface 5 and / or the perforating tip 3.

[0049] In the Figures 1 to 6Each of the embodiments of the perforating blade 1 according to the invention is shown in which a larger distance with a recess relative to the crimping surface 5 is present between the individual perforating elements 2. However, it is also possible for the perforating elements 2 to be arranged on the effective surface of the perforating blade 1 without a corresponding larger distance and / or without a corresponding recess.

[0050] The invention also includes a method for operating a device as described in the Fig. 1 to 6 illustrated and described perforating blade 1, wherein the perforating blade 1 according to the invention is brought into operative connection with a grooved or elastic counter surface serving as an abutment for the printing material to be perforated, and wherein the distance between the perforating blade 1 and the counter surface serving as an abutment for the printing material can be changed. List of reference symbols

[0051] 1Perforating knife 2Perforating element 3Perforating tip 4Foot point 5Crimp surface 6Circle 7Direction of rotation RaOuter radius R1first radius αInclination angle

Claims

1. Perforating knife (1), which is designed as a circular knife, for perforating at least one layer of a printing material to be processed into a printed product, wherein the perforating knife (1) comprises a plurality of perforating elements (2) on the circumference, wherein a perforating element (2) comprises at least one perforating tip (3), which extends in radial extension from an outer radius (Ra) to at least one base point (4) lying on a first radius (R1), wherein a crimping surface (5) adjoins the base point (4) on at least one side of the perforating tip (3), characterised in that at least one crimping surface (5) has an angle of inclination α to the circle (6) spanned by the first radius (R1), wherein the angle of inclination is defined between the tangent lying against the circle (6) at the base point (4) of the perforating tip (3) and the crimping surface (5).

2. Perforating knife (1) according to claim 1, characterised in that each crimping surface (5) has an extension limited in the circumferential direction.

3. Perforating knife (1) according to claim 1, characterised in that the angle of inclination α is in a range from 1° to 45°.

4. Perforating knife (1) according to one of claims 1 to 3, characterised in that the transition between the perforating tip (3) and at least one crimping surface (5) is rounded.

5. Perforating knife (1) according to one of claims 1 to 4, characterised in that between a perforating tip (3) and the crimping surface (5) adjacent thereto, a depression is formed with the first radius (R1) in relation to the region of the crimping surface (5).

6. Perforating knife (1) according to one of claims 1 to 5, characterised in that each perforating element (2) has a perforating tip (3) on its leading side, as seen in the direction of rotation (7), on which a crimping surface (5) adjoins, as seen in the opposite direction to the direction of rotation (7).

7. Perforating knife (1) according to one of claims 1 to 6, characterised in that each perforating element (2) has a perforating tip (3) on each leading and trailing side as seen in the direction of rotation (7).

8. Perforating knife (1) according to one of claims 1 to 5, characterised in that each perforating element (2) has a respective perforating tip (3) which is adjoined on both sides by a respective crimping surface (5).

9. Method for operating a perforating knife (1), characterised in that a perforating knife (1) according to one of claims 1 to 8 is brought into operative connection with a grooved or an elastic mating surface and the distance between the perforating knife (1) and the mating surface can be varied.

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