Device and method for compensating for press differences

Abstract

The invention relates to a device, particularly for use in printing press construction, comprising at least two rollers (1, 2) rolling against each other, wherein at least one first roller (1) has at least two journals (3, 4), the first roller (1) being designed as a hollow roller. According to the invention, at least one of the two journals (3, 4) is inserted into the first roller (1), the journal (3) having at least two different diameters (5, 6). Furthermore, the invention also includes a method for compensating for pressure differences between rollers (1, 2).

Description

[0001] The invention relates to a device, in particular in printing machine construction, comprising at least two rollers rolling on one another, wherein at least a first roller has at least two pins, wherein the first roller is designed as a hollow roller, and to a related method.

[0002] When two axially parallel rollers are pressed together, the rollers deform under linear pressure along their center axes in such a way that the center-to-center distance at the roller edges is smaller than in the roller center. The inhomogeneity of the pressure profile leads to inconsistent contact pressure and transfer behavior across the roller width.

[0003] Task The invention therefore aims to provide a device and a method for compensating pressure differences between rolls.

[0004] The SolutionThe object of the device is characterized in conjunction with the preamble of claim 1 in that at least one of the two pins is inserted into the first roller, wherein one pin has at least two different diameters.

[0005] To compensate for the uneven distribution of pressure between the rollers, it is proposed to change the shape of the bending line by pushing the pins of the roller deeper into the hollow roller.

[0006] According to a further development, the position of the pin in the hollow roller is defined by an insertion depth, wherein the insertion depth is variable. The insertion depth is preferably 30 mm, 60 mm, 90 mm, or particularly preferably 120 mm.

[0007] According to the further development, at least parts of the outer surface of the largest diameter of one of the pins are designed as a contact surface. The contact surface is preferably cylindrical.

[0008] Advantageously, one of the pins is firmly connected to the roller via the contact surface. The fixed connection can be created, for example, by screwing, welding, or gluing. A bolt-and-pin connection or a suitable fit is also conceivable. The fixed connection can also be made only at specific points. The contact surface should be of an appropriate size depending on the connection.

[0009] According to a further development, the journals are provided with different cross-sections, with the parts of the journal with different diameters having different lengths, whereby the different lengths depend on the insertion depth. The journal protrudes beyond the edge of the roller to enable mounting of the roller. Accordingly, the total length of the journal must be adapted to the insertion depth. The further the journal is inserted into the hollow roller, the greater the total length of the journal. The parts of the journal that do not form the contact surface have their own bending line. The contact surface between the journal and the hollow roller should be wide enough to fully transfer the bending moment acting on the roller during rolling to the journal, taking into account the component strength. Furthermore, the contact surface should be dimensioned in such a way that the rigidity of the roller is not proportionally increased.Various designs of the pin are conceivable, as can be seen, for example, from the figures. The pins can also have a bore, preferably a blind hole. The pins can also have several sections with different diameters, but at least the parts of the outer surface of the pin with the largest diameter are designed as a contact surface. The part of the pin with the largest diameter, which forms the contact surface with the first roller, can also have grooves so that only parts of the largest diameter are in contact with the first roller.

[0010] According to a further development, at least one of the rollers additionally has an elastic layer, wherein this elastic layer is a coating or a covering. The elastic layer can be made of a flexible material, such as rubber.

[0011] The solution to the problem regarding the method for compensating pressure differences, in conjunction with the preamble of claim 7, is characterized in that the resulting bending line is influenced by changing the insertion depth of the journal or by changing the stiffness of the journal and / or the roller. The stiffness of the journal is in a compatible relationship to the stiffness of the roller. The effect of the insertion depth increases disproportionately.

[0012] According to the further development, the pressure between the two rollers in the center of the roller and the roller edges is changed.

[0013] According to the further development, the bending line is influenced by changing the area moments of inertia and / or the material of the pin.

[0014] The development is intended to influence the natural frequency of the rolls. The greater the insertion depth of the journal, the lower the natural frequency of the roll-journal assembly.

[0015] Between the edge areas of the rollers and the journals, a series connection of two spiral springs is mechanically created on both sides, which exhibits greater flexibility with increasing insertion depth. In this way, the bending line of one roller in the center of the roller is partially decoupled from the bending line of the other roller along the contact line in the edge areas. Part of the deformation energy induced by the contact pressure is stored proportionally in the deformation of the journals. As a result, a flatter bending line profile is created in the contact line between the two rollers, with consequently lower edge pressure. The pressure difference between the roller center and the roller edges is thus reduced. The described properties make it possible to mitigate the inherent edge smearing, for example, in printing press construction. The described decoupling of the two bending lines can be moderated using the following parameters: Insertion depth of the journal into the hollow roller, area moment of inertia of the journal cross-section (outer-inner diameter of the journal) or section-wise introduction of additional compliance areas.

[0016] The invention is particularly suitable for improving the print image in printing presses, especially offset printing presses, since it offers a solution for compensating pressure differences between rollers, e.g., between the plate cylinder and the dampening roller. The roller with at least one inserted pin could, for example, be the dampening roller and / or the anilox roller.

[0017] The drawings show schematically a device according to the invention: Fig. 1 shows rollers rolling on each other with at least two journals. Fig. 2 shows a journal inserted into a hollow roller. Fig. 3 shows a journal with a bore inserted into a hollow roller. Fig. 4 shows a journal with a bore and several different diameters inserted into a hollow roller. Fig. 5 shows a side view of a hollow roller with a journal.

[0018] Figure 1shows two rollers 1, 2 rolling on each other. The first roller 1 is designed as a hollow roller. The first roller 1 has two journals 3, 4, wherein at least one of the journals 3, 4 is inserted into the first roller 1. The second roller 2 can be designed either as a hollow roller or as a solid roller. If the second roller 2 is designed as a hollow roller, it can have one or more journals that can be inserted into the hollow roller. At least one of the rollers 1, 2 additionally has an elastic layer 8, which can be a coating or a covering. The journal 3, 4 can be designed in different ways, as shown, for example, in the Figures 2 to 5 shown here. Figure 1The pin 3 shown has at least two different diameters 5, 6. At least parts of the outer surface of the largest diameter 5 of the pin 3 are designed as a contact surface 7. The pin 3 is firmly connected to the first roller 1 via the contact surface 7. The pin projects beyond the end face of the roller 1 to enable the roller to be supported. The position of the pin 3 in the first roller 1 is defined by the insertion depth a, which is variable. The length b of the largest diameter 5 of the pin 3 depends on the type of fixed connection between the pin 3 and the first roller 1 to ensure a minimum contact surface. The length c of the remaining pin 3 depends accordingly on the insertion depth a and the selected bearing.

[0019] Figure 2 shows a more detailed view of an inserted pin 3 in a first roller 1 designed as a hollow roller from Figure 1. The journal 3 projects beyond the end face of the hollow roller with a portion of its smaller diameter 6 for supporting the roller 1. The length c of this portion of the journal must be adapted to the selection of the bearing, the insertion depth a of the journal 3, and the length b of the largest diameter 5 of the journal 3. The position of the journal 3 in the roller 1 is defined by the insertion depth a. At least portions of the largest diameter 5 of the journal 3 form a contact surface 7 with the first roller 1. The journal 3 is firmly connected to the roller 1 via this contact surface 7.

[0020] Figure 3 also shows a first roller 1 designed as a hollow roller with an inserted pin 3. In contrast to Figure 2 This inserted pin 3 has a bore 9. This bore 9 can be used to moderate the flexural rigidity of the pin 3 and influence the area moment of inertia. The bore is designed as a blind hole.

[0021] Figure 4 shows how the Figures 2 and 3 a first roller 1 designed as a hollow roller with an inserted pin 3. This pin 3, however, has at least one further section with a further diameter.

[0022] Figure 5 shows a side view of a first roller 1 designed as a hollow roller with a journal 3. The journal 3 here has at least two different diameters 5, 6. The largest diameter 5 of the journal 3 here, for example, has grooves so that parts of the outer surface of the journal 3 form a contact surface 7 with the hollow roller.

[0023] The Figures 2 to 5 The embodiment described can also be implemented analogously for the pin 4 or for both pins 3 and 4. List of reference symbols

[0024] 1first roller 2second roller 3first journal / one journal 4further journal / other journal 5largest diameter 6diameter 7contact surface 8elastic layer 9bore a)insertion depth b)first length / length of the largest diameter of the journal c)second length / length of the remaining journal

Claims

1. Device, in particular in printing machine construction, comprising at least two rollers (1, 2) rolling on one another, wherein at least one first roller (1) has at least two pins (3, 4), wherein the first roller (1) is designed as a hollow roller, characterized in that at least one of the two pins (3, 4) is inserted into the first roller (1), wherein one pin (3) has at least two different diameters (5, 6).

2. Device according to claim 1, wherein the position of the one pin (3) in the hollow roller is defined by an insertion depth (a), wherein the insertion depth (a) is variable.

3. Device according to claim 1 or 2, wherein at least parts of the outer surface of the largest diameter (5) of one pin (3) is designed as a contact surface (7).

4. Device according to claim 3, wherein the one pin (3) is firmly connected to the first roller (1) via the contact surface (7).

5. Device according to at least one of claims 2 to 4, wherein the pins have different cross-sections, wherein the parts of the pin with the different diameters (5, 6) have different lengths (b, c), wherein the different lengths (b, c) are dependent on the insertion depth (a).

6. Device according to at least one of the preceding claims, wherein at least one of the rollers (1, 2) additionally has an elastic layer (8), wherein the elastic layer is a coating or a covering.

7. Method for compensating pressure differences between two rollers (1, 2), in particular in printing machine construction, with a device according to claim 1, wherein the resulting bending line is influenced by changing an insertion depth (a) of the pins (3, 4) or by changing the rigidity of the pin and / or the roller.

8. The method according to claim 7, wherein the pressure between the two rollers (1, 2) is changed in the roller center and the roller edges.

9. Method according to at least one of the preceding claims, wherein the bending line is influenced by changing the area moments of inertia and / or the material of the pin (3, 4).

10. Method according to at least one of the preceding claims, wherein the natural frequency of the composite of roller (1) and journal (3, 4) is influenced.

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