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

Abstract

A folding roller according to the invention with at least one circumferential groove (6) and a ring (5) arranged at least partially in the circumferential groove, comprising a material with a Shore A hardness in the range between 50 and 95 Shore, is characterized in that the ring (5) projects slightly beyond the surface of the folding roller (1, 2) and comprises at least one, preferably axially outer, elastic section (10), preferably a shoulder (10), which is at least partially radially deformable with respect to the folding roller (1), the groove (6) and / or a base (11) of the groove. The invention advantageously makes it possible to both transport and simultaneously fold printing materials precisely and smoothly.

Description

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

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

[0003] The industrial folding of sheet-shaped printed material is carried out using folding machines, which generally include a feeder for the sheets and at least one folding unit with multiple folding rollers. The folding units of the machine can each include pocket folders and / or blade folders.

[0004] The sheets are folded between two opposing, rotating folding rollers. The circumferential surfaces of the folding rollers can be made of metal. The folding rollers can have grooves in which rings made of an elastomer are held. State of the art

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

[0006] Two known but disadvantageous solutions of the prior art are described in detail in the Figures 1A and 1B The figures are shown and described below in relation to them. The disadvantages of such known solutions are also described there.

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

[0008] German patent DE 2905548 discloses a folding roller made of steel. The roller's surface has annular grooves. Pre-fabricated rings made of elastically deformable ("rubber-elastic") plastic are inserted into these grooves. The ring material has a hardness between 60 and 100 Shore A hardness units. The roller therefore has hard steel segments or hard plastic segments on its surface.

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

[0010] US 3120794 discloses a roller, different from 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 create improvements compared to the prior art, which in particular make it possible to transport and fold printed materials precisely and without interference. Inventive solution

[0012] These problems are solved according to the invention by a folding roller having the features of claim 1 and by further items according to claims 10 and 14. Advantageous and therefore preferred embodiments of the invention will become apparent from the dependent claims as well as from the description and the drawings.

[0013] A folding roller according to the invention, comprising at least one circumferential groove and a ring arranged at least partially in the circumferential groove, comprising a material with a Shore A hardness in the range between 50 and 95 Shore, is characterized in that the ring protrudes slightly beyond the surface of the folding roller and comprises at least one elastic section which is at least partially radially deformable with respect to the folding roller, the groove and / or a bottom of the groove.

[0014] 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), and in particular a so-called hard PU, e.g. a polyester urethane rubber.

[0015] In this application, "hard" material, in particular hard PU, is understood to mean: a material with a Shore A hardness between 50 and 95 Shore, in particular between 60 and 80 Shore, or in particular 75 + / - 5 Shore. The material is not foamed or only minimally foamed and is therefore essentially solid. The material can be, for example, Vulkollan®. Hard PU as a material for folding roller rings offers the advantage of being resistant to ink build-up, having a longer service life than, for example, rubber, and being "more grippy" than rubber, i.e., offering better substrate transport properties.

[0016] The material used according to the invention, 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), and in particular a so-called soft PU, e.g. a polyester urethane rubber.

[0017] In this application, "soft" material, in particular soft PU, is understood to mean a material with a Shore A hardness of less than 50 Shore. The material is preferably foamed and therefore essentially cellular or porous and consequently compressible. Soft PU is particularly advantageous for transporting smooth papers.

[0018] As an alternative to polyurethane (hard PU or soft PU), polyethylene or polypropylene can be used as a material, preferably as a hard or soft material, respectively.

[0019] Shore hardness or Shore A hardness is a material property 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.

[0020] The term "at least partially radial" means, for example, that in addition to a radial component, an axial component of mobility, positionability, or deformability may also be present. A minor axial component compared to the radial component is preferred, e.g., less than 10%, less than 5%, or less than 1%.

[0021] The folding roller according to the invention advantageously enables the precise and trouble-free transport and simultaneous folding of printed materials. The rings are preferably made of rigid polyurethane (PU). Due 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 inexpensive to manufacture and maintain. The folding roller advantageously preferably comprises only rings made of rigid PU and no rings made of soft PU.

[0022] An alternative folding roller according to the invention is a folding roller with circumferential grooves and rings for transporting and folding sheets of printing material, wherein either the grooves have a changing depth in the axial direction and / or the rings have a changing thickness in the axial direction.

[0023] The term "thickness varying in the axial direction" means, for example, that the thickness of the ring (depending on or as a function of its axial position) is not constant, or that the ring has significantly different thicknesses at at least two axial positions. For example, the thickness of the ring may have a step. The thickness is preferably measured in the radial direction or is a radial thickness.

[0024] The alternative folding roller according to the invention also advantageously enables the precise and trouble-free transport and simultaneous folding of printed materials. Furthermore, the roller or its rings are subject to low wear.

[0025] Due to their design, all folding rollers according to the invention offer an excellent combination of sheet guiding properties and folding properties. Further developments of the invention

[0026] A preferred embodiment of the invention may be characterized in that the section is a decentralized section, i.e., is arranged decentralized or off-center with respect to the ring in the axial direction.

[0027] A preferred embodiment of the invention may be characterized in that the section is an outer section, i.e., located externally in the axial direction with respect to the ring, preferably at the lateral edge of the ring.

[0028] A preferred embodiment of the invention is characterized by the formation of a circumferential chamber between the sections and the bottom of the respective groove, and by the chamber being filled with air or with a compressible material other than air. The chambers advantageously and simply enable the radial mobility and / or positioning of the sections or shoulders. The chambers or the corresponding cavities preferably provide sufficient hollow space for the shoulders, thereby enabling their mobility and positioning.

[0029] A preferred embodiment of the invention is characterized in that the chamber has a height measured in the radial direction which is constant in the axial direction, or 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.

[0030] A preferred embodiment of the invention is characterized in that the chamber has a height measured in the radial direction which is variable in the axial direction, or that the chamber has a wedge-shaped cross-section. By selecting the wedge-shaped cross-section, e.g., by choosing a suitable angle of the wedge, the spring rate of the section or shoulder can be precisely adjusted.

[0031] A preferred embodiment of the invention is characterized by a Shore A hardness in the range of 60 to 80 Shore or 75 + / - 5 Shore, and / or by the material being an elastic material, an elastomer, or rigid polyurethane, wherein the material is solid, non-cellular, or non-foamed. The spring rate of the section or shoulder can be precisely adjusted by selecting the appropriate material and Shore A hardness.

[0032] A preferred embodiment of the invention can be characterized by the fact that the ring protrudes a few hundredths of a millimeter above the surface of the folding roller.

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

[0034] The folding rollers according to the invention and their preferred embodiments are described in more detail below with reference to the drawings and by way of preferred exemplary embodiments. Corresponding features are identified in the figures by the same reference numerals.

[0035] The drawings show: Figures 1A and 1B are folding rollers according to the prior art; Figure 2 is a folding roller according to the invention; Figure 3 is a folding roller according to the invention; Figure 4 is a folding roller according to the invention; Figure 5 is a folding roller according to the invention; Figure 6 is a folding roller according to the invention; and Figure 7 is a folding roller according to the invention. Character description

[0036] Figure 1A Figure 1 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 form part or sections of the folding roller. These segments can have a corrugation on their surface in the axial direction. The soft segments can be made of a soft polyurethane and are 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 a larger proportion of hard segments 3 and a smaller proportion of soft segments 4 on its surface, e.g. in a ratio of approximately 3:2 or approximately 4:3. The hard segments of one roller overlap with hard segments of the roller opposite it in their respective overlap areas 7.

[0039] The hard segments 3 have the function of producing 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 transport of the material (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 disruptive lines can form in the material 102 being processed in the respective overlap areas, reducing the quality of the folded product. A further disadvantage is the wear of the roller surface.

[0041] Figure 1BFigure 1 shows another folding roller 1 according to the prior art. This folding roller also has 50 alternating hard segments 3 and soft segments 4 in the axial direction. The segments can be arranged according to the Figure 1A The solution shown is manufactured and exhibits the corresponding "Fold" and "Grip" functions during operation. The hard segments may have axial ribbing 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, 3:5, or 4:5. The soft segments 4 of one roller overlap with soft segments of the opposite roller in their respective overlap areas 7. The overlap can be, for example, a few millimeters. Therefore, compared to the Figure 1A not an overlap of hard segments, but an overlap of soft segments.

[0043] A disadvantage of this solution is that the soft segments result in a less precise fold, or rather, the "Grip" function is significantly more pronounced than the "Fold" function.

[0044] Figure 2 Figure 1 shows a preferred embodiment of a folding roller 1 of a folding machine 100 according to the invention, which preferably rotates together with a further 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 design. Therefore, the design of folding roller 1 is described below by way of example.

[0045] The folding roller 1, or its core, can be made of metal, preferably steel, and has (relative to an axis of rotation of the folding roller 1) alternating hard segments 3 and soft segments 4 in the axial direction 50. The hard segments 3 are formed alternately in the axial direction 50 by hard segments 3a and hard segments 3b. The hard segments 3a are preferably made of metal, in particular steel, and can be fixed / non-removable parts or sections of the folding roller 1. Alternatively, the hard segments 3a can be made of rigid polyurethane and designed as removable rings. The hard segments 3b are preferably made of rigid polyurethane and can be removable parts or sections of the folding roller or be mounted 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 according to the prior art, but rather of hard PU according to the invention. In order to achieve the formation of a soft segment despite the use of hard PU, the following is provided in this embodiment according to the invention: A ring 5 is at least partially arranged as a section-wise soft segment 4 in a circumferential groove 6 of the folding roller 1. 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 (rear-side, i.e., towards the roller core) indentation in its soft section.

[0047] The ring may protrude slightly, e.g., by a few hundredths of a millimeter, beyond the surface of the folding roller. The ring 5 has a central section 5a (relative to an axis of rotation of the folding roller 1 in the axial direction 50) and two axially outer sections 5b (also in the axial direction 50). The sections 5b are elastically deformable and radially movable or displaceable 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 pressure between the two rollers 1 and 2, preferably on the order of the protrusion, e.g., a few hundredths of a millimeter.

[0048] In the illustrated embodiment, 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). The groove has a depth 8a in section 6a and a shallower depth 8b in section 6b. The respective depths are measured relative to the surface of the folding roller 1 in the region of the hard segments 3a. The circumferential grooves of the folding roller 1 can, for example, be formed as indentations in the metal roller. The bottom 11 of the groove 6 is preferably stepped: a central, low step 11a and two adjacent, axially outer, high steps 11b.

[0049] The ring 5 has a thickness 9a in section 6a, which essentially corresponds to the depth of the groove 8a or is slightly greater (given a certain overhang). In section 6b, the ring has a thickness 9b that 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, or between the step 11b of the base of the groove 6 and section 6b. The chamber is preferably filled with air. Alternatively, the chamber can be filled with a compressible material, e.g., a soft polyurethane. The chamber preferably has a rectangular cross-section.

[0050] According to the invention, chamber 12 allows the respective shoulder 10 to move or shift in a radial direction 51 within or into the chamber. This enables the shoulders 10 of the ring 5 to function 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, thus providing the "grip" function.

[0051] The ring 5 is preferably glued into the groove 6, in particular to the base 11a or the step 11a of the base 11 of the groove. Excess adhesive 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 can also provide for movement or displacement of the hard PU material of the ring 5 in the radial direction 51 in section 15 and thus also provide the "grip" function in section 15.

[0053] Figure 2 This shows that the respective segments of the two rollers 1 and 2 are arranged offset from each other by an axial offset 52: The central section 5a of the ring 5 of the folding roller 1 is 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 are opposite each other. Given the slight overhang of the rings 5 ​​above the (preferably metallic) surface of the respective folding roller 1 or 2, the shoulders 10 are each moved or displaced slightly into their respective chamber 12. This creates the "grip" function, i.e., the shoulders act as if made of soft polyurethane. Advantageously, however, no soft polyurethane is used, but (in this embodiment) only hard polyurethane.

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

[0055] Figure 3 shows another preferred embodiment of the invention. The structure is comparable to that in Figure 2 However, as shown, the chambers 12 here have an essentially wedge-shaped cross-section and the bottom 11 of the groove 6 is not stepped (with the two steps 11a and 11b), but continuously shaped.

[0056] Figure 4This also shows another preferred embodiment of the invention. Again, the structure is comparable to that in Figure 2 As shown, however, steps 11a and 11b are designed differently here: the depth 8b of the axially outer bottom 11b is deeper than the depth 8a of the central bottom 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 therein, 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 under the shoulder. The ring, and in particular its shoulders, are considered as springs.

[0058] Figure 5Figure 1 also shows another preferred embodiment of the invention. The structure is again comparable to that in Figure 2. Figure 2 However, in this embodiment two types of segments 3 and 4 or rings 5 ​​and 5' are used: The rings 5 ​​are hard or made of hard PU and the rings 5' are soft or made of soft PU.

[0059] The rings 5 ​​are T-shaped and sit in grooves 6 of the roller 1; the grooves 6 themselves are stepless.

[0060] There is an axial gap 16 between the rings 5. The rings 5' sit on the surface of the roller 1 and between the rings 5 ​​or in the gaps 16. The rings 5' have a radial projection 19 beyond the rings 5 ​​to improve the grip function. The rings 5 ​​are held axially by the grooves 6; the rings 5' are held axially by the rings 5.

[0061] Roller 2 has grooves 17 in which soft rings 5' or rings 5' made of soft PU are received; these are opposite the rings 5' of roller 1. Hard surface segments 18, e.g. made of steel, are opposite the rings 5' of roller 1 on roller 2.

[0062] The rings 5' of rollers 1 and 2, acting together, provide the "Grip" function; the rings 5 ​​and the segments 18, acting together, provide the "Fold" function. The rings 5' of both rollers 1 and 2 can be identical. Alternatively, the rings 5' of roller 2 can be slightly wider than the rings 5' of roller 1, so that they overlap with the rings 5 ​​of roller 1 and the "Grip" function is improved.

[0063] Figure 6 shows another preferred embodiment of the invention. Again, the structure is comparable to that in Figure 2However, as shown, each ring 5 has only one axially outer section 5b formed as a shoulder 10. A ring 5 of roller 1, or rather one of its shoulders 10, overlaps only with a ring 5 of roller 2, or rather one of its shoulders 10. The sides of the rings 5 ​​without formed shoulders do not overlap or only overlap insignificantly.

[0064] Figure 7 shows another preferred embodiment of the invention. In contrast to the Figures 2 to 6 Are the two rollers 1 and 2 in Figure 7 The rings 5 ​​are shown spaced apart so that their curvature is clearly visible. In operation, however, the rollers are positioned against each other and the rings 5 ​​are pressed into the grooves 6, so that the curvatures are either not present or less pronounced. Again, the setup is comparable to that shown in Figure 2However, in this embodiment, the axial sections for the "grip" function are not formed 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. The curvature is preferably chosen such that a central section protrudes relative to axially outer (radial) sections. Reference symbol list

[0065] 1 Folding roller 2 Folding roller 3 Hard segments 3a Hard segments (made of steel) 3b Hard segments (made of hard PU) 4 Soft segments (made of soft PU) 5 Rings (hard) 5' Rings (soft) 5a Central sections of the rings 5b Axially outer sections of the rings 6 Grooves 6a Central sections of the grooves 6b Axially outer sections of the grooves 7 Overlap areas 8a Depth of the grooves 8b Depth of the grooves 9a Thickness of the rings 9b Thickness of the rings 10 Shoulders of the rings / Axially outer sections of the rings 11 Bottom of the groove 11a Bottom of the grooves (steps) 11b Bottom of the grooves (steps) 12 Chambers 12a Height of the chamber 13 Side chambers 14 Central recesses 15 Sections 16 Gaps 17 Grooves 18 Surface segments (hard) 19 Radial overhang 50 Axial direction (of the folding roller and / or ring) 51 Radial direction 52 Axial offset 100 Folding machine 101 Folding product 102 Material to be processed

Claims

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

2. Folding roller according to claim 1, characterized by that the section is a decentralized section, ie is arranged decentrally or off-center with respect to the ring (5) in the axial direction (50).

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

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

5. Folding roller according to claim 4, characterized by 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 by 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 to one of the preceding claims, characterized by thatthe 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 or an elastomer or rigid polyurethane, wherein the material is solid or non-cellular or non-foamed.

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

9. Folding roller according to one of the preceding claims, characterized by that the ring (5) protrudes a few hundredths of a millimeter above the surface of the folding roller (1, 2) 10. Pair of folding rollers for transporting and folding sheets of printing material, comprising at least one folding roller (1, 2) according to one of the preceding claims.

11. Folding roller pair according to claim 10, characterized by thatboth folding rollers (1, 2) of the folding roller pair are designed according to one of the preceding claims.

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

13. Folding roller pair according to claim 12, characterized by that Grooves (6) and / or rings (5, 5') of one of the two folding rollers (1, 2) have an axial offset (52) with respect to identical grooves (6) and / or rings (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 claims 1 to 9 or with at least one pair of folding rollers (1, 2) according to one of claims 10 to 13.

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