Folding roller with a circumferential groove and a ring arranged in the circumferential groove

Abstract

A folding roller according to the invention, comprising at least one circumferential groove (6) and a ring (5) arranged at least partially in the circumferential groove and comprising a material with a Shore A hardness in the range between 50 and 95 Shore, is characterized in that the ring (5) comprises at least one elastic section (10), preferably an axially external one, preferably a shoulder (10), which is at least partially radially movable and / or positionable and / or deformable with respect to the folding roller (1), the groove (6) and / or a bottom (11) of the groove. The invention advantageously enables the precise and trouble-free transport and simultaneous folding of printed materials.

Description

[0001] The invention relates to a folding roller according to claim 1 and further objects according to claims 10 and 14. Technical field of the invention

[0002] The invention lies in the technical field of the graphic industry and in particular in the area of ​​folding printing materials, such as paper.

[0003] The industrial folding of sheet-shaped printing materials is carried out using folding machines, which typically comprise a sheet feeder and at least one folding unit with a plurality of folding rollers. The folding units of the machine can each comprise buckle plate folding units and / or knife folding units.

[0004] The sheets are folded between two rotating folding rollers positioned opposite each other. The peripheral surfaces of the folding rollers can be made of metal. The folding rollers can have grooves in which elastomer rings are accommodated. State of the art

[0005] DE7904616U1 discloses a folding roller equipped with a friction jacket and rings made of elastically deformable material. The rings can be grooved on their outer surface. DE2854957A1 and DE3743642A1 disclose similar devices.

[0006] Two known but disadvantageous state-of-the-art solutions are described in detail in the Figures 1A and 1B shown and are described below with reference to these figures. The disadvantages of such known solutions are also described there.

[0007] EP2960194A1 discloses a folding roller with grooves for guiding folding belts. Rubber-elastic or compressible inserts or rings are arranged in the grooves below the folding belts. The conveyor belts can have a projection of approximately 0.05-0.5 mm above the outer surface of the folding roller. The inserts therefore do not project beyond the outer surface.

[0008] DE2905548 discloses a steel folding roller. Ring grooves are incorporated into the roller's casing. Prefabricated rings made of elastically deformable ("rubber-elastic") plastic are inserted into these grooves. The material of the rings has a hardness between 60 and 100 Shore A units. Accordingly, the roller has hard steel segments or hard plastic segments on its surface.

[0009] JP2006076676A discloses a pair of folding rollers, each folding roller having, in its axial direction, alternating rubber rings with a hardness of about 30° and a hardness of 60° or more.

[0010] US3120794 discloses a roller other than a folding roller with a sealing ring. The sealing ring may have a shoulder. Task

[0011] It is therefore an object of the invention to provide improvements over the prior art which, in particular, make it possible to both transport and simultaneously fold printing materials precisely and smoothly. Inventive solution

[0012] These objects are achieved according to the invention by a folding roller having the features of claim 1 and by further objects according to claims 10 and 14. Advantageous and therefore preferred developments of the invention emerge from the subclaims as well as from the description and the drawings.

[0013] The material used according to the invention with a Shore A hardness in the range between 50 and 95 Shore is preferably an elastic material, more preferably an elastomer and in particular a polyurethane (PU), more particularly a so-called hard PU, e.g. a polyester urethane rubber.

[0014] In this application, a "hard" material, particularly hard PU, is defined as a material with a Shore A hardness between 50 and 95 Shore, in particular between 60 and 80 Shore, or especially 75 + / - 5 Shore. The material is not foamed or only slightly foamed and is therefore essentially solid. The material can be Vulkollan®, for example. Hard PU as a material for folding roller rings offers the advantage of being resistant to ink buildup and having a longer service life than, for example, rubber. It also offers "greater grip" than rubber, meaning it offers better substrate transport properties.

[0015] The material used with a Shore A hardness in the range below 50 Shore is preferably an elastic material, more preferably an elastomer and in particular a polyurethane (PU), more particularly a so-called soft PU, e.g. a polyester urethane rubber.

[0016] In this application, a "soft" (or "soft") material, especially soft PU, is defined as a material with a Shore A hardness of less than 50. The material is preferably foamed and therefore essentially cellular or porous, and consequently compressible. Soft PU is particularly advantageous for transporting smooth paper. As an alternative to polyurethane (hard PU or soft PU), polyethylene or polypropylene can be used, preferably as a hard or soft material.

[0017] The Shore hardness or Shore A hardness is a material characteristic for elastic materials, elastomers and / or plastics and can be determined in accordance with the standards DIN EN ISO 868, DIN ISO 7619-1 and ASTM D2240-00.

[0018] A folding roller according to the invention with at least one circumferential groove and a ring arranged at least partially in the circumferential groove and comprising a material with a Shore A hardness in the range between 50 and 95 Shore, is characterized in that the ring projects slightly beyond the surface of the folding roller and comprises at least one elastic section which is at least partially radially either movable and / or positionable with respect to the folding roller, the groove and / or a bottom of the groove.

[0019] The term "at least partially radial," for example, means that in addition to a radial component, an axial component of mobility / positionability / deformability can also be present. An axial component that is insignificant compared to the radial component, e.g., less than 10%, less than 5%, or less than 1%, is preferred.

[0020] The folding roller according to the invention advantageously enables printing materials to be transported and folded precisely and smoothly. The rings are preferably made of hard PU. Thanks to the sections according to the invention (hereinafter also referred to as "shoulders"), the relatively hard rings advantageously behave, at least in sections, like soft PU rings. The roller is simple and cost-effective to manufacture and maintain. The folding roller advantageously preferably has only rings made of hard PU and no rings made of soft PU.

[0021] Due to their design, folding rollers according to the invention each offer an excellent combination of sheet guiding properties and folding properties.

[0022] A ring made of elastic material for a folding roller with a circumferential groove for receiving the ring can preferably be characterized in that the ring has a changing thickness in the axial direction.

[0023] Such a ring can preferably be characterized in that the ring has one shoulder or two shoulders, wherein the thickness of the shoulder or shoulders is reduced with respect to the thickness of the ring or the thickness of the ring at its thickest point

[0024] Such a ring, or its use, advantageously enables precise and trouble-free transport and simultaneous folding of printing materials. Furthermore, such a ring is wear-resistant. Further developments of the invention

[0025] A preferred development of the invention can be characterized in that the section is a decentralized section, ie it is arranged decentrally or off-center with respect to the ring in the axial direction.

[0026] A preferred development of the invention can be characterized in that the section is an outer section, ie is arranged on the outside with respect to the ring in the axial direction, preferably on the lateral edge of the ring.

[0027] A preferred development of the invention can be characterized in that a respective circumferential chamber is formed between the sections and the bottom of the respective groove, and in that the chamber is filled with air or with a compressible material other than air. The chambers advantageously and easily enable the radial mobility and / or positioning of the sections or shoulders. The chambers or the corresponding cavities preferably achieve a sufficient hollow position of the shoulders and thus, in turn, their mobility / positionability.

[0028] A preferred embodiment of the invention can be characterized in that the chamber has a height measured in the radial direction that is constant in the axial direction, or in that the chamber has a rectangular cross-section. By selecting the length and height of the rectangle, the spring rate of the section or shoulder can be precisely adjusted.

[0029] A preferred embodiment of the invention can be characterized in that the chamber has a height measured in the radial direction that is variable in the axial direction, or in that the chamber has a wedge-shaped cross-section. By selecting the wedge-shaped cross-section, e.g., by selecting a corresponding wedge angle, the spring rate of the section or shoulder can be precisely adjusted.

[0030] A preferred embodiment of the invention can be characterized in that the Shore A hardness is in the range between 60 and 80 Shore or 75 + / - 5 Shore and / or that the material is an elastic material, an elastomer, or rigid polyurethane, wherein the material is solid, non-cellular, or non-foamed. By selecting the material and the Shore A hardness, the spring rate of the section or shoulder can be precisely adjusted.

[0031] A preferred development of the invention can be characterized in that the ring projects slightly beyond the surface of the folding roller.

[0032] A preferred development of the invention can be characterized in that the ring projects a few hundredths of a millimeter above the surface of the folding roller.

[0033] The features of the invention, the further developments of the invention, and the exemplary embodiments of the invention, even in any combination with one another, represent advantageous further developments of the invention. Further developments of the invention may also have the individual features or combinations of features disclosed in the above section "Technical Field of the Invention." Embodiments of the invention

[0034] The folding rollers according to the invention and their preferred developments are described in more detail below with reference to the drawings using preferred embodiments. Corresponding features are provided with the same reference numerals in the figures.

[0035] The drawings show: Figures 1A and 1B show folding rollers according to the prior art; Figure 2 shows folding rollers according to the invention; Figure 3 shows folding rollers according to the invention; Figure 4 shows folding rollers according to the invention; Figure 5 shows folding rollers according to the invention; and Figure 6 shows folding rollers according to the invention. Character description

[0036] Figure 1A shows a folding roller 1 according to the prior art, which interacts with another folding roller 2. Both rollers are preferably arranged in a folding machine 100 and serve to produce folded products 101 from material 102 to be processed.

[0037] The folding roller 1 has alternating hard segments 3 and soft segments 4 in the axial direction (direction 50 in the figure). The hard segments can be made of metal, in particular steel, and can be part or sections of the folding roller. These segments can have axial ribbing on their surface. The soft segments can be made of a soft polyurethane and can be designed as rings 5', which are mounted on the roller. The rings can be arranged in circumferential grooves 6 of the folding roller. The same applies to the folding roller 2.

[0038] The folding roller 1 has, with respect to its surface, a larger proportion of hard segments 3 and a smaller proportion of soft segments 4, e.g., in a ratio of approximately 3:2 or approximately 4:3. The hard segments of one roller overlap in respective overlap areas 7 with hard segments of the opposite roller.

[0039] During operation, the hard segments 3 have the function of creating a good fold in the material 102 to be processed, e.g., paper (hereinafter referred to as the "Fold" function), while the soft segments 4 have the function of ensuring good material transport (hereinafter referred to as the "Grip" function). The folding rollers according to the invention described below also have these two functions.

[0040] A disadvantage of this prior art solution is that clearly visible and therefore disturbing lines can arise in the material 102 to be processed in the respective overlap areas 7, which reduce the quality of the folded product. A further disadvantage is the wear of the roller surface.

[0041] Figure 1Bshows another folding roller 1 according to the prior art. This folding roller also has alternating hard segments 3 and soft segments 4 in the axial direction 50. The segments can be arranged according to the Figure 1A They can be manufactured according to the solution shown and exhibit corresponding "fold" and "grip" functions during operation. The hard segments can have a serration in the axial direction on their surface.

[0042] The folding roller 1 has a higher proportion of soft segments 4 and a lower proportion of hard segments 3 on its surface, e.g., in a ratio of approximately 2:5 or 3:5 or 4:5. The soft segments 4 of one roller overlap in respective overlap areas 7 with soft segments of the opposite roller. The overlap can, e.g., be approximately a few millimeters. Therefore, in comparison to the Figure 1A not an overlap of hard segments, but an overlap of soft segments.

[0043] The disadvantage of this solution is that the soft segments mean that the fold break is created less precisely and the "Grip" function is much more pronounced than the "Fold" function.

[0044] Figure 2 shows a preferred embodiment of a folding roller 1 according to the invention of a folding machine 100, which preferably cooperates in a rotational manner with another folding roller 2. The folding rollers serve to produce folded products 101 from material 102 to be processed, e.g., paper. Both folding rollers 1 and 2 can have a similar structure. Therefore, the structure of the folding roller 1 is described below by way of example.

[0045] The folding roller 1 or its roller core can be made of metal, preferably steel, and has (relative to a rotational axis of the folding roller 1) alternating hard segments 3 and soft segments 4 in the axial direction 50. The hard segments 3 are formed in the axial direction 50 by alternating hard segments 3a and hard segments 3b. The hard segments 3a are preferably made of metal, in particular steel, and can be fixed / non-detachable parts or sections of the folding roller 1. Alternatively, the hard segments 3a can be made of hard PU and designed as detachable rings. The hard segments 3b are preferably made of hard PU and can be detachable parts or sections of the folding roller or can be accommodated on the folding roller.

[0046] The soft segments 4 (or shoulders or bending beams) are preferably not made of soft PU, as would be expected from the prior art, but according to the invention of hard PU. In order to ensure that a soft segment can be formed despite the use of hard PU, the following is provided according to the invention in this embodiment: A ring 5 is at least partially arranged in a circumferential groove 6 of the folding roller 1 as a sectionally soft segment 4. The ring has a Shore A hardness in the range between 60 and 90 Shore, preferably between 60 and 80 Shore and particularly preferably around 75 Shore. The material of the ring is preferably solid, non-cellular or non-foamed. The ring 5 can have a recess (on the rear, i.e. towards the roller core) in its soft section.

[0047] The ring protrudes slightly, e.g., by a few hundredths of a millimeter, above the surface of the folding roller. The ring 5 has a central section 5a (in the axial direction 50 relative to a rotational axis of the folding roller 1) and two axially outer sections 5b (in the axial direction 50). The sections 5b are elastically deformable and can be moved or displaced radially with respect to the folding roller 1 and / or in particular with respect to the groove 6 in the folding roller and / or a bottom 11 of the groove (in the radial direction 51). The latter means that the sections 5b are moved or displaced radially into the groove under pressure, e.g., by pressing between the two rollers 1 and 2, preferably by a distance of a few hundredths of a millimeter.

[0048] In the embodiment shown, the groove 6 has two sections: a central section 6a (in the axial direction 50) and two axially outer sections 6b (in the axial direction 50). In sections 6a, the groove has a depth 8a and in section 6b a smaller depth 8b. The respective depths are measured relative to the surface of the folding roller 1 in the area of ​​the hard segments 3a. The circumferential grooves of the folding roller 1 can, for example, be manufactured as recesses in the metal roller. The base 11 of the groove 6 is preferably stepped: a central, low step 11a and two adjacent, axially outer, high steps 11b.

[0049] In section 6a, the ring 5 has a thickness 9a which is essentially the same as the depth of the groove 8a or slightly greater (for a given overhang). In section 6b, the ring has a thickness 9b which is less than the depth of the groove 8b, e.g., only 50%, 60%, 70%, 75%, 80%, or 90%. This creates a circumferential chamber 12 between each (axially outer) shoulder 10 of the ring 5 and the respective base 11b, i.e., the step 11b of the base of the groove 6 or the section 6b. The chamber is preferably filled with air. Alternatively, the chamber can be filled with a compressible material, e.g., soft PU. The chamber preferably has a rectangular cross-section.

[0050] According to the invention, the chamber 12 enables the respective shoulder 10 to be movable or displaceable in the radial direction 51 within or into the chamber. As a result, the shoulders 10 of the ring 5 act during operation (i.e., during transport and folding of the material 102) – despite being made of hard PU – similarly to those made of soft PU, enabling the provision of the "grip" function.

[0051] The ring 5 is preferably glued into the groove 6, particularly glued to the bottom 11a or the step 11a of the bottom 11 of the groove. Excess glue can be collected in two circumferential side chambers 13.

[0052] The ring 5 can optionally have a central and circumferential recess 14 (in the axial direction). This recess can also provide mobility or displacement of the hard PU material of the ring 5 in the radial direction 51 in section 15, thus also providing the "grip" function in section 15.

[0053] Figure 2 shows that the respective segments of the two rollers 1 and 2 are arranged offset from one another by an axial offset 52: The central section 5a of the ring 5 of the folding roller 1 lies opposite a hard segment 3a of the folding roller 2 and vice versa. The shoulders 10 of the rings 5 ​​of both folding rollers 1 and 2 lie opposite one another. Given a slight projection of the rings 5 ​​over the (preferably metal) surface of the respective folding roller 1 or 2, the shoulders 10 are each moved or displaced slightly into their associated chamber 12. This creates the "grip" function, i.e. the shoulders appear to be made of soft PU. Advantageously, however, no soft PU is used, but (in this embodiment) only hard PU.

[0054] As an alternative to the embodiment shown, the base 11 of the groove 6 can also be designed to be continuous. The chambers 12 would then be deeper, provided the thickness 9b of the shoulders 10 of the ring 5 remains the same. The thickness 9b can also be selected to be larger so that the chambers are not too deep. In the area of ​​the shoulders 10, the projection of the ring 5 in this embodiment can also be selected to be greater than 15 / 100 mm, or conversely, the ring 5 can be designed to be thinner centrally, i.e., axially between the shoulders, e.g., by turning.

[0055] Figure 3 shows a further preferred embodiment of the invention. The structure is comparable to that in Figure 2 shown, however, the chambers 12 here have a substantially wedge-shaped cross-section and the bottom 11 of the groove 6 is not step-shaped (with the two steps 11a and 11b), but is stepless.

[0056] Figure 4also shows a further preferred embodiment of the invention. Again, the structure is comparable to that in Figure 2 shown, but here the steps 11a and 11b are designed differently: the depth 8b of the axially outer base 11b is deeper than the depth 8a of the central base 11a. Or in other words: the groove 6 has a central, high step 11a and two adjacent, axially outer, low steps 11b.

[0057] In all embodiments shown according to the Figures 2 to 4 The respective spring rate of the rings 5 ​​shown there, or their axially outer sections / shoulders 10, can be adjusted as follows: selection of the hard PU material; selection of the axial length and radial thickness of the shoulders; and / or selection of the axial length and radial depth of the groove below the shoulder. The ring, and in particular its shoulders, are considered a spring.

[0058] Figure 5shows a further preferred embodiment of the invention. Again, the structure is comparable to that in Figure 2 shown, however, the rings 5 ​​each have only one axially outer section 5b formed as a shoulder 10. A ring 5 of the roller 1 or its one shoulder 10 overlaps only with a ring 5 of the roller 2 or its one shoulder 10. The sides of the rings 5 ​​without formed shoulders do not overlap or overlap only insignificantly.

[0059] Figure 6 shows a further preferred embodiment of the invention. In contrast to the Figures 2 to 6 The two rollers 1 and 2 in Figure 7 are shown spaced apart from each other, so that the rings 5 ​​and, in particular, their curvature are clearly visible. During operation, however, the rollers are positioned against each other and the rings 5 ​​are pressed into the grooves 6, so that the curvatures are not or less pronounced. Again, the structure is comparable to that shown in Figure 2shown, however, the axial sections for the "grip" function in this embodiment are not caused by shoulders but by a curvature of the ring 5. The ring is designed, for example, such that its cross-section corresponds to a curved or bent rectangle.

[0060] The curvature is preferably selected such that a central section protrudes (radially) relative to axially outer sections. List of reference symbols

[0061] 1Folding roller 2Folding roller 3Hard segments 3aHard segments (made of steel) 3bHard segments (made of hard PU) 4Soft segments (made of soft PU) 5Rings (hard) 5aCentral sections of the rings 5bAxially outer sections of the rings 6Grooves 6aCentral sections of the grooves 6bAxially outer sections of the grooves 7Overlap areas 8aDepth of the grooves 8bDepth of the grooves 9aThickness of the rings 9bThickness of the rings 10Shoulders of the rings / axially outer sections of the rings 11Bottom of the groove 11aBottom of the grooves (steps) 11bBottom of the grooves (steps) 12Chambers 12aHeight of the chamber 13Side chambers 14Central recesses 15Sections 16Gaps 17Grooves 50Axial direction (of folding roller and / or ring) 51radial direction 52axial offset 100Folding machine 101Folded product 102Material to be processed

Claims

1. Folding roller with at least one circumferential groove (6) and a collar (5) arranged at least partially in the circumferential groove and comprising a material with a Shore A hardness in the range between 50 and 95 Shore, characterized in that the collar (5) projects slightly beyond the surface of the folding roller (1, 2) and comprises at least one flexible axial section (10) which is either radially movable and / or positionable at least in part with respect to the folding roller (1, 2), the groove (6) and / or a base (11) of the groove.

2. Folding roller according to claim 1, characterized in that the section is an off-center section, i.e. is arranged off-center or eccentrically with respect to the collar (5) in the axial direction (50).

3. Folding roller according to claim 1 or 2, characterized in that the section is an outer section, i.e. is arranged on the outside in the axial direction (50) with respect to the collar (5).

4. Folding roller according one of the preceding claims, characterized in that a respective circumferential chamber (12) is formed between the sections (10) and the base (11) of the respective groove (6) and in that the chamber is filled with air or with a compressible material other than air.

5. Folding roller according to claim 4, characterized in that the chamber (12) has a height (12a) measured in the radial direction, which is constant in the axial direction, or that the chamber has a rectangular cross-section.

6. Folding roller according to claim 4, characterized in that the chamber (12) has a height (12a) measured in the radial direction, which is variable in the axial direction, or that the chamber has a wedge-shaped cross-section.

7. Folding roller according one of the preceding claims, characterized in that the Shore A hardness is in the range between 60 and 80 Shore or at 75 + / - 5 Shore and / or that the material is an elastic material or an elastomer or rigid polyurethane, wherein the material is solid or non-cellular or non-foamed.

8. Folding roller according one of the preceding claims, characterized in that the collar (5) adjoins a segment (3a) of the folding roller (1, 2) made of steel or another collar (5) made of an elastomer with a Shore A hardness in the range between 90 and 100.

9. Folding roller according one of the preceding claims, characterized in that the collar (5) protrudes a few hundredths of a millimeter above the surface of the folding roller (1, 2).

10. A pair of folding rollers for transporting and folding sheets of printing substrate, comprising at least one folding roller (1, 2) according to one of the preceding claims.

11. A pair of folding rollers according to claim 10, characterized in that both folding rollers (1, 2) of the pair of folding rollers are designed according to one of the preceding claims.

12. A pair of folding rollers according to claim 10 or 11, characterized in that the folding rollers (1, 2) of the pair of folding rollers are arranged offset relative to one another in the axial direction (50) with respect to their grooves (6) or collars (5, 5').

13. A pair of folding rollers according to claim 12, characterized in that grooves (6) and / or collars (5, 5') of one of the two folding rollers (1, 2) have an axial offset (52) with respect to identical grooves (6) and / or collars (5, 5') of the other of the two folding rollers (1, 2).

14. Folding machine with at least one folding roller (1, 2) according to one of the claims 1 to 9 or with at least one pair of folding rollers (1, 2) according to one of the claims 10 to 13.

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