CH714638A2 - Punching device for producing shaped labels. - Google Patents

Abstract

In a punching device for producing shaped labels from a starting stack of sheet-like material, comprising: a hollow cylindrical punching knife (2) and a lifting device (3) with a lifting plate (5) to a stack on the lifting plate (5) lying stack of benefits by the punching knife (2 ) to push by the output stack is pushed in a punching direction against the punching knife (2); it is provided that the lifting plate (5) has a compensating body (6) on the cutting blade side, wherein the compensating body (6) is designed such that within a cutting contour (9) of the punching blade (2) and circumferentially spaced therefrom an elevation (10 ), which projects beyond a lifting plate plane (S) defined by the cutting contour (9).

Description

description

Technical Field The invention relates to an apparatus and a method for punching a stack of sheet-like material for the production of shaped labels.

Technical Background The so-called piercing is often used to produce shaped labels. An output stack of sheet-like material is pushed against a hollow cylindrical punching knife by means of a lifting device. the stack that forms the finished form labels, is pressed through the punch knife and the cut off excess is removed outside the punch knife. The punched stack of sheets is automatically pushed further through the subsequent stack and then conveyed on through a downstream banding device, again divided into individual stacked sheets and provided with a belt. When the punching knife penetrates the starting stack, depending on the starting material and / or the flat dimension of the utility stack, the problem can arise that the upper flat products of the stack bulge (force or voltage discharge), which leads to inaccuracies in the form of the piercing process Labels and leads to an overhang of the benefit stack (situation-related puncture status).

In order to largely suppress the bulging during the piercing process and thus to increase the accuracy of the punching, the same applicant proposed in EP 0 735 938 to press a press stamp on the opposite side of the lifting device onto the stack in order to stack the stack in one Press holding by the punch knife. Even higher accuracies were achieved with a press stamp, which fits the hollow cylindrical punching knife precisely and thus exerts pressure on the entire surface of the stack of sheets. After punching, the stack of sheets is pressed out of the punching knife against the punching direction using the punch. A disadvantage of the earlier counterpressure process, however, is the lower throughput rate, because the stack of blanks has to be ejected from the punching knife by means of the press ram and, seen in the punching direction, has to be pushed back and to the side in order to feed a banding device, which ultimately results in higher production costs for the shaped labels. In addition, such devices are significantly more expensive than devices without a counter-pressure process.

[0004] EP 2 944 440 from the same applicant overcomes this disadvantage and describes a punching method with a counterpressure device, in which the counterpressure is applied to a stack of blanks that have already been punched, at least partially protruding from the punching knife.

DESCRIPTION OF THE INVENTION It has now been shown that, in the case of punching processes in which a punched stack of sheets is automatically pushed further by the subsequent stack of sheets, the subsequent stack of sheets with or without counterpressure also has an overhang in the upper region (ie in the region of the first Punching knife drives). This was particularly evident in the case of strongly resilient starting stacks made of, for example, plastic films.

An object of the invention is to avoid the overhang in subsequent batches. This object is achieved by a punching device according to claim 1.

The invention is now based on the knowledge that the overhang is caused by bulging due to voltage discharge of the already fully or partially punched stack of benefits against the punching direction. A subsequent exit stack then reproduces this bulge, which, due to the curvature, leads to an excessive punching out of the uppermost layers of sheet-like material.

The punching device for the production of shaped labels from an output stack of sheet-like material comprises a hollow cylindrical punching knife and a lifting device with a lifting plate in order to press a stack of benefits lying on the lifting plate through the punching knife, in which the starting stack is pushed against the punching knife in a punching direction becomes. The lifting plate has a compensating body on the punching knife side, the compensating body being designed in such a way that an elevation is obtained within a cutting contour of the punching knife and circumferentially spaced therefrom, which protrudes beyond a lifting plate plane defined by the cutting contour. In other words, the expansion and arrangement of the compensation body is such that the compensation body is offset inwards relative to the cutting contour of the punching knife.

With cutting contour, the contour or outline is meant, which (r) by a projection of the cutting edge of the punch knife vertically resp. against the punching direction on the lifting plate. This cutting contour also corresponds to the line of contact of the punching knife with the lifting plate when the lifting plate is guided up to the punching knife. This contact line lies in the lifting plate level. The cut contour also defines the outer contour of the shape label.

Experiments have shown that after the punching process the lowermost layers of the starting stack in the middle - i.e. within the cutting contour - be pressed increasingly in the punching direction. The tension in the last punched sheet-like material of the stack of sheets is discharged in the punching direction and bulging of the punched sheet of stack against the punching direction is prevented. A subsequent exit stack can then face up against the punch

CH 714 638 A2 knife and there is no curvature of the top layers of the original stack. An excess in the upper area of the subsequent stack of benefits is thus prevented.

In some embodiments, the compensating body can be placed on a flat surface of the lifting plate or integrated into it. The compensating body can be attached as a replacement part or screwed tight. Alternatively, the compensating body and the lifting plate can be formed in one piece, in which case the lifting plate is preferably designed to be exchangeable.

In some embodiments, the compensating body and / or the lifting plate can be exchangeably mounted in the lifting device. This enables a simple exchange or. Adjust the compensation body to a replaced punch knife.

In some embodiments, the compensation body can be designed in the form of a flat compensation plate.

In some embodiments, the compensating body can be designed in the form of a bulge with flattened sides which merge into the lifting plate plane. Such laterally flattened compensating bodies allow the output stacks to be pushed onto the lifting plate more easily.

In some embodiments, to form the compensating body, the lifting plate can have a groove encircling the compensating body, which protrudes on both sides from the cutting contour.

In some embodiments, the lifting plate can comprise a support plate on which the compensating body is arranged. This has the advantage that the lifting device can be easily adapted to changed punching knives. [0017] In some embodiments, an outer contour of the compensating body can be offset inwards by at least 10 mm with respect to the cutting contour. The compensating body can protrude at its thickest point 0.5 mm to 2 mm, preferably about 1 mm above the lifting plate level.

An exchangeable compensating body can be easily adapted to the needs and optimized with regard to the material to be punched and the shape of the resulting labels.

In all embodiments, both the support plate and the compensating body can be made of plastic, aluminum or steel.

BRIEF EXPLANATION OF THE FIGURES The invention is to be explained in more detail below on the basis of exemplary embodiments in conjunction with the drawing (s). It shows:

1 under FIGS. 1 a to 1f schematic representations of the punching process and the formation of an undesired bulging of a stack of sheets;

Figure 2 is a schematic side view of a lifting plate with a compensating body.

3 shows a schematic view of the surface of a lifting plate with a compensating body;

4 shows a schematic side view of a lifting plate with a flattened compensating body;

5 shows a schematic view of a milled lifting plate;

6 shows a schematic view of a lifting plate with a support plate; and

Fig. 7 under Fig. 7a to Fig. 7c schematic representations of the punching process with a compensating body.

WAYS OF IMPLEMENTING THE INVENTION FIG. 1 schematically shows a punching device under FIG. 1a, individual steps of a typical punching method being shown under FIGS. 1b to 1e. 1f finally shows a punched-out stack of benefits 4 ′ with an undesired overhang 8.

The output stacks 1, 1 'to be punched come from a face-cutting device as a single or double stack to the punching device. The punching device for producing shaped labels comprises a lifting device 3, a hollow cylindrical punching knife 2 and optionally a counter pressure element (not shown), which are arranged one after the other in a punching direction A along a punching conveying path 11. This allows complete straight-line guidance up to a subsequent banding device (not shown). The lifting device 3 has a flat lifting plate 5, which serves to push output stacks 1, 1 'of sheet-like material in the punching direction A against the punching knife 2, the utility stacks 4, 4' being pressed through the hollow cylinder of the punching knife 2 (FIG. 1b to 1e). The cut excess of the output stack 1, which is obtained outside the hollow cylinder and is carried away as waste, is

CH 714 638 A2 not shown. The punching direction A defines the punching conveyor path 11 along which the output stacks 1, 1 'and the punched utility stacks 4, 4' are conveyed by the stroke of the lifting device 3.

It has now been shown that an already punched utility stack 4, which is still in the hollow cylindrical punch knife 2 (see FIG. 1c), bulges downwards in the direction of the lifting plate 5 as soon as the lifting plate 5 for the subsequent output stack 1 'has returned. This bulging of the benefit stack 4 is shown in Fig. 1d.

If a subsequent output stack 1 'is pushed against the punching knife 2 by means of the lifting device 3, the uppermost layers of the sheet-like material of the subsequent output stack 1' can bend due to the low force which the bulge exerts on the subsequent stack. This ultimately leads to the punching knife starting too far out in the uppermost layers of the subsequent exit stack T and the corresponding shape labels having an excess. The resulting utility stack 4 * corresponds at least in the uppermost region to an overhang 8, as is shown schematically in FIG. 1f.

Fig. 2 shows a schematic side view of a lifting plate 5 with a compensating body 6. Fig. 3 shows a schematic view of the surface of a lifting plate 5 with compensating body 6. The compensating body 6 in the embodiment shown in Fig. 2 is in the form a compensation plate on the cutting knife side placed on the flat lifting plate 5. The compensating body 6 forms an elevation within the cutting contour 9 (cf. FIG. 3) of the punching knife, which protrudes beyond the lifting plate plane S. The thickness of the compensating body 6 can be 0.5 mm to 2 mm. In the case of an approximately uniformly thick compensating body 6, this is preferably offset inward at a distance of several millimeters from the cutting contour 9 and can essentially have the shape of the cutting contour 9.

With the cutting contour 9, the contour or the outline is meant, which (r) by a projection of the cutting edge of the punching knife 2 perpendicularly. against the punching direction A on the lifting plate 5. This cutting contour 9 also corresponds to the contact line of the punch knife 2 with the lifting plate 5 when the lifting plate 5 is guided up to the punch knife 2. This contact line lies in the lifting plate plane S. The cutting contour 9 also defines the outer contour of the shape label.

4, a compensating body 6 is shown, which is not formed uniformly thick, but is flattened laterally. This flattening makes it easier to push an output stack 1, 1 'onto the lifting plate 5. With such a configuration of the compensating body 6, it can also extend almost to the cutting contour 9 and does not have to be spaced from it by several millimeters.

Another embodiment is shown in FIG. 5. The compensating body 6 is made in one piece with the lifting plate 5 and is formed by a circumferential groove 12 milled into the lifting plate 5, which protrudes on both sides beyond the cutting contour 9. The lifting plate level S lies at the level of the groove 12.

Fig. 6 shows an embodiment in which the lifting plate 5 is provided with a support plate 13, for example made of plastic. The lifting plate level is defined by the support plate 13 and the compensating body 6 is placed on the support plate 13 or molded onto it.

7a to 7c show a schematic representation of the punching process using a compensating body 6. In this case, at the end of a punching process, the utility stack 4 is pressed a little further in the punching direction relative to the edge area in the center by the compensating body 6, so that a lower region of the utility stack 4 is concavely bent inwards (cf. FIG. 7a). After the lifting plate 5 is pulled back to receive the next exit stack 1 ', the last punched-out stack 4 can be relieved. Experiments have shown, however, that the utility stack 4 no longer bulges over the knife edge (cf. FIG. 7b) and the subsequent exit stack V with the upper layers is pushed flat against the punching knife 2. A curvature of the upper layers is avoided and the resulting stack of panels 4 'has a constant outer contour over the entire length, so that no overhang is formed.

List of designations [0031]

1.1 'exit stack

punching knife

lifting device

4.4 'utility stack

lifting plate

compensation body

bulge

overhang

CH 714 638 A2

sectional contour

survey

Punching conveying path

groove

platen

A punching direction

S lifting plate level

claims

Claims (10)

1. A punching device for producing shaped labels from an initial stack (1, Γ) from sheet-like material, comprising: a hollow cylindrical punching knife (2) and a lifting device (3) with a lifting plate (5), around a stack of sheets (5) resting on the lifting plate (5) 4, 4 ') by the punch knife (2) by pushing the exit stack (1, 1') in a punching direction (A) against the punch knife (2); characterized in that the lifting plate (5) has a compensating body (6) on the punching knife side, the compensating body (6) being designed such that an elevation (10) is located within a cutting contour (9) of the punching knife (2) and circumferentially spaced therefrom results which protrudes over a lifting plate plane (S) defined by the cutting contour (9). 2. Punching device according to claim 1, characterized in that the compensating body (6) is placed on a flat surface of the lifting plate (5) or is integrated therein. 3. Punching device according to claim 1, characterized in that the compensating body (6) and the lifting plate (5) are integrally formed. 4. Punching device according to one of the preceding claims, characterized in that the compensating body (6) and / or the lifting plate (5) are interchangeably mounted in the lifting device (3). 5. Punching device according to one of the preceding claims, characterized in that the compensating body (6) is designed in the form of a flat compensating plate. 6. Punching device according to one of the preceding claims, characterized in that the compensating body (6) is designed in the form of a bulge with flattened sides which merge into the lifting plate plane (S). 7. Punching device according to one of the preceding claims, characterized in that to form the compensating body (6), the lifting plate (5) has a compensating body (6) encircling groove (12) which protrudes from both sides of the cutting contour (9). 8. Punching device according to one of the preceding claims, characterized in that the lifting plate 5 comprises a support plate 13 on which the compensating body is arranged. 9. Punching device according to one of the preceding claims, characterized in that an outer contour of the compensating body (6) with respect to the cutting contour (9) is offset inwards by at least 10 mm. 10. Punching device according to one of the preceding claims, characterized in that the compensating body (6) protrudes 0.5 mm to 2 mm, preferably about 1 mm above the lifting plate plane (S) at its thickest point.