Sheet-fed rotary printing press with at least one directly driven cylinder

Abstract

Sheet-fed rotary printing press with at least one directly driven cylinder mounted in the machine frame (11) of the sheet-fed printing press, the longitudinal axis of which is radially displaceable relative to the machine frame (11) by a predefinable amount and which has a cylinder journal to which a rotary encoder comprising a rotor and stator is assigned, wherein the rotor is assigned to the cylinder journal and the stator to the machine frame (11), such that an elastic coupling element is provided between the stator and the machine frame (11), characterized in that the elastic coupling element allows a radial deflection by at least the amount of the change in position of the cylinder.

Description

[0001] The invention relates to a sheet-fed rotary printing press with at least one directly driven cylinder according to the preamble of claim 1.

[0002] Rotary printing presses, such as sheetfed offset presses, are increasingly being used in which individual cylinders are separated from the central continuous drive train, which is driven by at least one main drive, and driven individually. For example, plate cylinders can have a separate drive motor (individual drive) to, for instance, rotate all plate cylinders simultaneously into the plate-changing position and perform the plate change on all printing units at the same time. This saves setup time.

[0003] To synchronize the rotary motion of individually driven plate cylinders with the respective adjacent rubber blanket cylinders, which together with the other drums or cylinders are driven by a main drive via a central drive gear train, rotary angle encoders are arranged both on the drive shaft of the plate cylinder and on the shaft of the adjacent rubber blanket cylinder, the stator (housing) of which is connected to the machine frame by means of an arbitrarily arranged anti-rotation device.

[0004] To adapt to the thickness of the substrate being processed, the position of the rubber cylinder relative to the corresponding printing cylinder changes. This necessitates a change in the center-to-center distance between the rubber cylinder and the plate cylinder to maintain the pressure between them. Consequently, the position of the plate cylinder's pivot pin also changes, and thus the position of the encoder's stator relative to the frame.

[0005] Hollow shaft encoders are increasingly used as rotary encoders for such cylinders. Hollow shaft encoders are rotary encoders equipped with a hollow shaft that is slid over the drive shaft and attached to it on the rotor side.

[0006] For coupling hollow shaft encoders to the frame, compensating couplings are normally used. These compensating couplings are designed to compensate for radial and axial runout errors while ensuring a torsionally rigid connection between the stator and the machine. Such compensating couplings are known from WO 2010 / 012581 A1, DE 196 29 585 A1, and EP 1 757 908 B1. These compensating couplings are neither designed nor suitable for applications requiring radial adjustment of the cylinder axes. Therefore, torque arms are typically used, which connect the stator to the machine frame in a rotationally rigid manner.

[0007] From DE 196 35 796 C2, a mounting for a rotary encoder of a cylinder of a rotary printing press driven by an individual electric drive is known. The cylinder is adjustable in position relative to another cylinder. A connecting link is mounted on the journals of both cylinders, which is rigid in the direction of rotation about the axes of rotation of the journals, but otherwise allows changes in the distance between the cylinders. The housing of the rotary encoder is mounted on the link, and the housing of the rotary encoder is fixedly connected to the link.

[0008] In the arrangements of the rotary encoder described above using a torque support, a disadvantage is that the housing of the hollow shaft encoder is rotated with the adjustment movement of the cylinders, thus generating a faulty encoder signal.

[0009] The invention is based on the objective of designing a fastening for a rotary encoder which eliminates the aforementioned disadvantages and enables a cost-effective, torsionally rigid connection between the rotary encoder and the machine frame.

[0010] According to the invention, the problem is solved by a device having the features of claim 1.

[0011] The invention will now be explained by way of example. The accompanying drawings illustrate: Fig. 1: Illustration of the installation situation of the elastic coupling element Fig. 2: Illustration of the elastic coupling element according to the invention Fig. 3: Illustration of the elastic coupling element in deflected state (maximum deflection)

[0012] In the Fig. Figure 1 shows a cylinder pair consisting of a plate cylinder 1 and a rubber cylinder 2. The longitudinal axis of the plate cylinder 1 can be displaced radially relative to the machine frame 11 of the sheet-fed rotary printing press by a predefinable amount by a device not shown here. Outside the area shown, a printing cylinder is associated with the rubber cylinder 2. The rubber cylinder 2 has a rubber cylinder journal 3 on both ends, which is mounted in the machine frame 11 of the sheet-fed printing press.

[0013] The plate cylinder 1 has a plate cylinder journal 6, which is also mounted in the machine frame of the sheet-fed printing press, to which a rotary encoder designed as a hollow shaft encoder 7 is assigned. This consists essentially of a rotary encoder housing 8 (also referred to as the stator of the hollow shaft encoder 7) and a hollow shaft 9 (also referred to as the rotor).

[0014] The hollow shaft 9 is rigidly connected to the plate cylinder journal 6, while the encoder housing 8 is mounted in the machine frame 11 of the sheet-fed printing press via an elastic compensating coupling 10. Such compensating couplings are originally designed to compensate for unavoidable runout and misalignment errors. These errors range up to 0.03 mm. The design of these compensating couplings also allows for axial compensation of the cylinder in question relative to the machine frame 11.

[0015] The construction of such a compensating coupling 10 is shown in the Fig. 2. The compensating coupling 10 shown there has a base body 13 which is equipped on both sides with a stator flange 14 for mounting on the encoder housing 8. At 90° OOffset from each of the stator flanges 14 is a frame bracket 15, which is rigidly connected to the machine frame 11 of the sheet-fed printing press. The stator flanges 14 are almost rigidly connected to the base body 13, while the frame brackets 15 have an elastic connection to the base body 13. This is achieved by assigning a bent section 17, connected to the base body 13, to each frame bracket 15 via two spacers 16.

[0016] Regarding the mode of operation of the device according to the invention: As in the Fig. As can be seen in Figure 1, the rubber cylinder 2, with its outer surface 4, corresponds to the outer surface 5 of the plate cylinder 1, which is represented by solid lines in the figure. This is the case during printing. Sometimes, it is technologically necessary to disengage the plate cylinder 1 from the rubber cylinder 2 while maintaining contact between the rubber cylinder 2 and the printing cylinder. This occurs, for example, when the printing plates on the plate cylinder 1 are being changed, maintenance work is required, or the direct drive motor of the plate cylinder 1 is used to drive the inking unit. The contact between the rubber cylinder 2 and the printing cylinder must be maintained if the printing press continues printing in this case and the rubber cylinder 2 is required for sheet transport.

[0017] To achieve this, the longitudinal axis of the plate cylinder 1 is displaced radially relative to the machine frame 11 by a predefinable amount using a known device (not shown in detail here) mounted in the machine frame 11. That is, the position of the plate cylinder 1 is changed relative to the position of the rubber cylinder 2 by moving the axis of the plate cylinder 1 (in the Fig. (1 represented by point A) is shifted around point C to point B. Point A represents the longitudinal axis of the plate cylinder 1, in which Fig. 1 is represented by the plate cylinder pivot 6. This change in position, when the printing plate is changed, when the inking unit is washed, or when the plate surface of plate cylinder 1 and the blanket of rubber cylinder 2 are brought out of contact for other technological reasons, corresponds at least to the amount of pressure between plate cylinder 1 and rubber cylinder 2. In practice, this amounts to 0.2 mm and more. The amount of this change in position is therefore many times greater than the deflections that occur when compensating for runout and misalignment errors.

[0018] This also changes the position of the rotary encoder housing 8, since it is connected to the plate cylinder journal 6 via the hollow shaft 9. This changed position is shown in the Fig. 1 is shown with a dashed line. This also shifts the base body 13 and the parts connected to it, although this is not shown in the drawing for clarity. The change in position is greatly exaggerated for the sake of clarity.

[0019] From the Fig. Figure 1 shows that the position of the rotary encoder housing 8 changes in an adjustment direction 18. The mounting in the machine frame 11 of the sheet-fed printing press ensures that the position of the frame brackets 15 does not change, so that the change in position of the rotary encoder housing 8 relative to the machine frame 11 is accommodated by the deformation of the bent parts 17. The bent parts 17 are dimensioned such that they allow at least the amount of the change in position of the plate cylinder 1.

[0020] In the Fig. Figure 3 illustrates this clearly, although the deformation has also been exaggerated here. It becomes evident that the elastic coupling element allows a radial deflection that is greater than the radial deflection required to compensate for runout and / or misalignment errors. The direction of this radial deflection lies approximately on the line connecting the axes of plate cylinder 1 and rubber cylinder 2 and is shown in the Fig. 1 and Fig. 3 is indicated by a directional arrow, which corresponds to the adjustment direction 18. It can be seen that the elasticity of the bending parts 17 allows a corresponding deflection in this preferred direction. The deflection in this preferred direction exceeds the elasticity of the other directions several times over. List of reference symbols used 1 plate cylinder 2 rubber cylinders 3 rubber cylinder pins 4. Surface area of ​​the rubber cylinder 5. Lateral surface area of ​​the plate cylinder 6 plate cylinder pins 7 Hollow shaft rotary encoders 8 Rotary encoder housings 9 Hollow shaft 10 compensating clutch 11 machine frame 13 basic shapes 14 Stator flange 15 Frame tab 16 spacer 17 Bent part 18 Adjustment direction

Claims

Sheet-fed rotary printing press with at least one directly driven cylinder mounted in the machine frame (11) of the sheet-fed printing press, the longitudinal axis of which is radially displaceable relative to the machine frame (11) by a predefinable amount and which has a cylinder journal to which a rotary encoder comprising a rotor and stator is assigned, wherein the rotor is assigned to the cylinder journal and the stator to the machine frame (11), such that an elastic coupling element is provided between the stator and the machine frame (11), characterized in that the elastic coupling element allows a radial deflection by at least the amount of the change in position of the cylinder. Sheet-fed rotary printing press according to claim 1, characterized in that the elastic coupling element has a direction-dependent elasticity. Sheet-fed rotary printing press according to claim 2, characterized in that the elasticity in the adjustment direction (18) of the cylinder exceeds that of the other directions by a multiple. Sheet-fed rotary printing press according to claim 1, characterized in that the rotary encoder is designed as a hollow shaft rotary encoder (7), wherein its hollow shaft (9) is associated with the cylinder pin and its rotary encoder housing (8) is associated with the machine frame (11).

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