DE102018212139A1 - Rotary punch for punching press sheets - Google Patents

Abstract

A rotary punch for punching of printed sheets (DB) comprises a counter-pressure cylinder (1) with grippers (2) for holding the printed sheets (DB), a punching cylinder (3) with a channel (4), in which during rotation (R) of the punching cylinder (FIG. 3) and the impression cylinder (1), the grippers (2) dive, and further comprises a distance sensor (5) which is directed to the punching cylinder (3).

Description

The present invention relates to a rotary punch for punching of printed sheets, comprising a counter-pressure cylinder with grippers for holding the sheet and a punching cylinder with a channel in which dive in rotation of the punching cylinder and the impression cylinder, the grippers.

Such a rotary punch can be part of a printing machine for inline stamping or a machine separate from the printing press for offline punching.

In DE 101 47 486 A1 is described a rotary die, which is integrated in a printing press. During operation of the rotary die, the punching cylinder can heat up and consequently increase in diameter. In practice, the punching cylinder can grow approx. 5 μm per operating hour. As a result, the pressure between the punching cylinder and the counter-pressure cylinder may increase excessively, which may result in damage to the punching blades of the punching cylinder.

The invention has for its object to provide a less susceptible to interference rotary die.

This object is achieved by a rotary die with the features of claim 1.

The rotary die-cutting press according to the invention comprises a counter-pressure cylinder with grippers for holding the printing sheets, a punching cylinder with a channel in which the grippers dip during rotation of the punching cylinder and the counter-pressure cylinder and further comprises a distance sensor which is directed onto the punching cylinder.

In the case of the rotary punch according to the invention, there is the advantage that thermally induced deformations of the punch cylinder can be detected in good time before they lead to complications, and that the pressure between the punch cylinder and the impression cylinder can be regulated with the aid of the distance sensor.

Various developments of the rotary die according to the invention are possible. For example, the distance sensor can operate according to an optical, inductive or preferably capacitive measuring method. The capacitive is preferred over the optical measuring method because the capacitive distance sensor is less susceptible to contamination than the operating distance measuring sensor according to the optical measuring method. Punching can cause paper dust that can dirty the sensor. The capacitive measuring method is preferred over the inductive, because the capacitive measuring method is favorable in terms of a design of the punching cylinder as a magnetic cylinder. The punching cylinder can be equipped with permanent magnets that hold a punching plate on the punching cylinder. Due to the permanent magnets, the measuring accuracy of the distance sensor operating according to the inductive measuring method would possibly be impaired.

The distance sensor may be positioned in a fixed position relative to the axis of rotation of the punching cylinder. For example, the distance sensor may be attached to a side wall of the rotary die. The mounting position can be chosen so that the distance sensor 0.5 to 5 mm, preferably 1 to 3 mm sitting above the peripheral surface of the punching cylinder. This ensures that the punching plate arranged on the peripheral surface, the thickness of which can be 0.5 to 0.7 mm, passes the distance sensor without colliding therewith during the cylinder rotation.

With the distance sensor data can be determined during the punching operation, which serve to correct the pressure between the punching cylinder and the impression cylinder. A computer of the rotary die can form an average value from the determined data and store it as a reference value after actuation of a key, the so-called good-bow key, by the operator. The machine or its computer and the sensor connected to it can automatically determine new values in the cycle. The controller of the rotary die to which the computer belongs may derive a change in pressure from the values, which may be automatic or only after confirmation by the operator.

In the program running in the computer it can be provided that the adjustment of the pressure with respect to the reference value is permissible only in the direction of a reduction of the pressure and not in the direction of an increase of the pressure. The measurement can be clocked so that it takes place only on an uncovered area of the punching cylinder, z. B. in a cylinder channel that is ground. Alternatively, the measurement can also take place in the outer region of the cylinder channel lying jacket area, which is covered by the punching plate. However, the punching plate usually does not have the quality required for a high-precision measurement, which is why the target region lying in the cylinder channel is advantageous for the distance sensor.

The distance sensor may be attached to a machine side wall of the rotary die. In this case, although the pressure adjustment would be recognized, but would a larger measuring range needed. The larger measuring range would be necessary in order to be able to take account of the different thicknesses of the printed sheets during the measurement from job to job. Therefore, an attachment of the distance sensor to a variable with the axis of rotation of the punch cylinder relative to the machine side wall component is more advantageous.

Further developments will become apparent from the following description of an embodiment and the accompanying drawings.

The sole figure of the drawing shows a rotary die of a printing press.

In the figure is a rotary die with an impression cylinder 1 and a punching cylinder 3 shown. The impression cylinder 1 has grapple 2 for holding a printed sheet DB , The punching cylinder 3 has a channel 4 that does not pass through a punching plate 10 is covered, the punching cylinder 3 on its circumference 9 wearing. The grippers 2 the impression cylinder 1 which the printed sheet DB hold clamped at its front edge, stand on the periphery of the impression cylinder 1 something about and therefore dive into the channel 4 of the punching cylinder 3 at every cylinder revolution.

To a control device 6 belong to a calculator 12 and a distance sensor 5 ,

With an adjusting device 11 can be an axis of rotation RA of the punching cylinder 3 to the impression cylinder 1 be adjusted to and from this, the pressure between the punching cylinder 3 and the impression cylinder 1 to adjust. The adjusting device 11 For example, an eccentric bearing of the punching cylinder 3 , Include a coupling gear and a motorized spindle drive, wherein the spindle drive via the coupling gear drives the eccentric bearing.

The distance sensor 5 is on a component 13 the adjustment 11 or of the linkage arranged such that a fixed distance FA between the distance sensor 5 and the punching cylinder 3 or its scope 9 with adjustments V of the punching cylinder 3 remains constant for the pressure adjustment.
Alternatively and preferably, it is also possible, the fixed distance FA not to the extent 9 of the punching cylinder 3 but on its axis of rotation RA to acquire.

In the channel 4 there is an inner surface 7 that the distance sensor 5 serves as the target surface during the measurement. The distance sensor 5 takes the measurement over a certain surface size 8th which is symbolized in the drawing by the length of a phantom line. A rotation R of the punching cylinder 3 and also the rotation of the impression cylinder 1 be by a motor M powered by the controller 6 is linked. Through the link knows the controller 6 at any time the existing rotational position of the punching cylinder 3 ,

The distance sensor 5 is through the control device 6 with the rotation R of the punching cylinder 3 synchronized. Here is the distance sensor 5 with the rotation R of the punching cylinder 3 synchronized such that the distance sensor 5 Measurements with respect to the inner surface 7 of the canal 4 performs.

According to a modification, not shown in the drawing, it could instead be provided that the distance sensor 5 with the rotation R of the punching cylinder 3 is synchronized such that the distance sensor 5 Perform measurements with respect to a free measurement area, which is on the circumference 9 of the punching cylinder 3 or the punching plate arranged thereon 10 located.

The distance sensor 5 is with the adjustment 11 connected by control technology, for adjusting the punching cylinder 3 relative to the impression cylinder 1 serves. The adjusting device 11 corrected as a function of measured values of the distance sensor 5 the pressure between the punching cylinder 3 and the impression cylinder 1 , The distance sensor 5 is synonymous with the calculator 12 in which a reference value for correcting the pressure between the punching cylinder 3 and the impression cylinder 1 is stored. The computer 12 calculated from the measured values of the distance sensor 5 an average, which forms said reference value.

The computer 12 allows corrections only to the reference value reducing the pressure between the punching cylinder 3 and the impression cylinder 1 to.

The distance sensor 5 is on the component 13 attached, which is the fixed distance FA at the adjustments V of the punching cylinder 3 relative to the impression cylinder 1 preserved. In this case, the component 13 and thus the distance sensor 5 the fixed distance FA relative to the punching cylinder 3 or possibly also relative to the axis of rotation RA of the punching cylinder 3 on.

LIST OF REFERENCE NUMBERS

1

Impression cylinder

2

grab

3

punching cylinder

4

channel

5

distance sensor

6

control device

7

palm

8th

Measuring area size

9

scope

10

punch plate

11

adjustment

12

computer

13

component

DB

sheet

FA

fixed level

M

engine

R

rotation

RA

axis of rotation

V

adjustment

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10147486 A1 [0003]

Claims (10)

Rotary punch for punching of printed sheets (DB), comprising a counter-pressure cylinder (1) with grippers (2) for holding the printed sheets (DB), - A punching cylinder (3) with a channel (4), in which during rotation (R) of the punching cylinder (3) and the impression cylinder (1), the grippers (2) are immersed, and - A distance sensor (5) which is directed to the punching cylinder (3). Rotary punch to Claim 1 , wherein the distance sensor (5) by a control device (6) with the rotation (R) of the punching cylinder (3) is synchronized. Rotary punch to Claim 2 wherein the distance sensor (5) is synchronized with the rotation (R) of the punching cylinder (3) so as to make measurements with respect to an inner surface (7) of the passage (4). Rotary punch to Claim 2 in that the distance sensor (5) is synchronized with the rotation (R) of the punching cylinder (3) such that it makes measurements with respect to a free measuring surface located on the circumference (9) of the punching cylinder (3) or on a punching plate arranged thereon (10). Rotary punching after one of Claims 1 to 4 , wherein the distance sensor (5) with an adjusting device (11) for adjusting the punching cylinder (3) is connected relative to the impression cylinder (1). Rotary punch to Claim 5 , wherein the adjusting device (11) corrects the pressure between the punching cylinder (3) and the impression cylinder (1) as a function of measured values of the distance sensor (5). Rotary punching after one of Claims 1 to 6 wherein the distance sensor (5) is connected to a computer (12) in which a reference value for correcting the pressure between the punching cylinder (3) and the impression cylinder (1) is stored. Rotary punch to Claim 7 wherein the computer (12) calculates a mean value of measured values of the distance sensor (5), which forms the reference value. Rotary punch to Claim 7 or 8th in which the computer (12) permits corrections exclusively with respect to the reference value reduction of the pressure between the punching cylinder (3) and the impression cylinder (1). Rotary punching after one of Claims 1 to 9 , wherein the distance sensor (5) is attached to a component (13) having a fixed distance (FA) relative to the punching cylinder (3) and the fixed distance (FA) at displacements (V) of the punching cylinder (3) relative to the impression cylinder (1 ).

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