WO1999033618A1

WO1999033618A1 - Cutting device for a plastic seal

Info

Publication number: WO1999033618A1
Application number: PCT/EP1998/008438
Authority: WO
Inventors: Wolfhard Schwarz
Original assignee: Alcoa Deutschland Gmbh Verpackungswerke
Priority date: 1997-12-29
Filing date: 1998-12-23
Publication date: 1999-07-08
Also published as: CZ293237B6; HU222222B1; HUP0100047A2; DE59803573D1; EA200000725A1; EA001669B1; DE19758040C2; CA2316815A1; UA42893C2; JP2001526971A; ES2173665T3; PL188265B1; CA2316815C; EP1044085A1; HUP0100047A3; DE19758040A1; EP1044085B1; PL341385A1; CZ20002414A3

Abstract

The invention relates to a device for making a cut in the peripheral direction of a plastic seal, comprising at least one blade, said blade being held by a holding device, and a fixing device for the seal. The invention is characterised in that the holding device (11) can be moved in relation to a path of motion (7) of the seal (3) by means of a control mechanism (29), in that the seal (3) is arranged in such a way that it can turn around its middle axis (5), and in that the cut is made by turning the seal (3) around its middle axis (5), the distance between the seal (3) and the blade (15) remaining constant or essentially constant whilst the seal is being turned.

Description

Cutting device for a plastic closure

description

The invention relates to a device for introducing at least one cut running in the circumferential direction of a plastic closure, with at least one knife, according to the preamble of claim 1.

A cut made in the circumferential direction of a plastic closure serves, for example, to form a guarantee ring which, when opening a container onto which the plastic closure is placed, is separated at least in sections from the plastic closure and / or is irreversibly deformed in such a way that opening the container for the first time is indicated is. Devices of the type mentioned here are known. They have a plurality of fixedly arranged knives, past which a plastic closure which can be displaced along a movement path is passed. In general, three knives arranged one behind the other in the direction of displacement of the closure are used for this purpose, to which the closure is pressed and thereby rolls along the movement path due to its displacement movement. In this case, each knife makes a partial cut extending over 120 ° of the circumferential surface of the closure, which is adjacent to one another, thereby forming a continuous cut. With the known cutting device, a continuous cut is made in the circumference of the closure, but the cut points due to the knife arrangement and cutting edge geometry - seen in the circumferential direction - different depth. The course of the cut is such that the depth of cut is very small in the initial area of a knife, becomes larger towards the center of the knife and becomes smaller again from the middle to the end area of the knife. This course of depth of cut cannot guarantee in all cases that the forces acting on the guarantee ring when the container is opened are sufficient to damage or deform it in the desired manner, so that opening for the first time cannot be detected with certainty. Another disadvantage of the different depth of cut is that the guarantee ring in the areas with the greatest depth of cut can be separated from the closure in sections during its manufacture or when it is placed on the container, which in turn impairs the reliability of the guarantee ring.

It is therefore an object of the invention to provide a device by means of which a cut running in the circumferential direction of a closure can be made with a constant, or at least essentially constant, depth.

To achieve this object, a cutting device with the features of claim 1 is proposed. This is characterized in that the holding device can be displaced with respect to a movement path of the closure via a control, that the closure is rotatably mounted about its central axis, and that the cut is made by rotating the closure about its central axis. can be brought, the distance between the closure and the knife being constant or substantially constant during the rotation. With a circumferential cut, the closure is rotated through 360 °. To introduce the cut running in the circumferential direction of the closure, the closure is first brought together with the knife fixed by a holding device and, after contacting the knife, rotated in a defined manner about its central axis. At least one cut running in the circumferential direction of the closure is made with a constant depth. The uniform depth of cut over the circumference of the closure is achieved in that the distance between the closure and the knife is not changed during the rotation of the closure about its central axis. This means that at least the area of the knife with the smallest distance to the central axis of the closure has a fixed position with respect to the closure during the cutting process. Since only a single knife is required to make the cut running in the circumferential direction of the closure, the construction of the cutting device can be simplified and thus its costs can be reduced.

Particularly preferred is an embodiment of the cutting device, which is characterized in that the path of movement of the closure is a circular path and that the holding device holding the knife is displaceable along a closed, curved contour path, the center of which lies on the center of the circular path. The cutting device has a carousel-like structure, that is to say that the closure and knife or the holding device holding the knife are removed together during the cutting process. along the path assigned to them, preferably at the same rotational speed.

In a preferred embodiment of the cutting device, the control is designed as a curve control, which here has a disk curve. This is scanned by a probe element which interacts with the holding device for the knife. The probe element is preferably connected to the holding device to which the knife is attached. The contour path along which the holding device is displaced is thus determined by the disk curve.

In an advantageous development of the invention, the depth of cut is adjustable. This makes it possible to adapt or adjust the cutting device to plastic closures with different wall thicknesses, shapes and / or from different plastics.

Also preferred is an embodiment of the cutting device in which the position of the knife relative to the closure can be adjusted. As a result, a defined cutting angle can be set so that the cutting surface is inclined by an angle that is greater than 0 ° and less than 90 ° with respect to an imaginary horizontal. In another embodiment it is provided that the cut surface formed during the cutting process is parallel to the imaginary horizontal, that is to say perpendicular to the circumferential surface of the closure. Further advantageous embodiments result from the remaining subclaims.

The invention is explained below with reference to the drawing. It shows:

Figure 1 is a plan view of an embodiment of the cutting device according to the invention and

FIG. 2 shows a side view of an exemplary embodiment of a holder for the closure.

FIG. 1 shows a plan view of a schematic diagram of an exemplary embodiment of a device, referred to below as the cutting device 1, for making at least one cut in a closure 3 made of plastic, which is used for closing a container, for example a bottle. The closure 3 is rotatably supported about its central axis 5 by means of a holder shown in FIG. In this exemplary embodiment, the movement path 7 is a circular path with the center 9. The closure 3 is shown in FIG. 1 in a plurality of positions A to F, which it assumes or traverses in succession within the cutting device 1.

The cutting device 1 comprises a holding device 11 which can be displaced around the center 9 of the movement path 7 and which has an adjusting element 13 to which a knife 15 is fastened. The adjusting element 13 is guided in a groove 17 and can be attached using at least one fastening means 19, for example by means of two locking screws the holding device 11 are fixed. The longitudinal central axis 20 of the groove 17 intersects the center point 9, that is to say that the knife 15 can be displaced in the direction of the center point 9 as well as in the direction of the movement path 7 by moving the adjusting element 13 in the groove 17. The holding device 11 further comprises a guide member 21 for the closure 3, which has a the closure receiving, open-edged, semi-circular recess ^"23. The recess 23 is 7 facing side surface of the guide part is introduced, starting from a plane, the path of movement 25 21 in this. The Knife 15 fastened to the adjusting element 13 is positioned on the holding device 11 in such a way that, in order to engage the closure, it projects into the recess 23 of the guide part 21, whereby the depth of the cut to be made in the circumference of the closure 3 is determined The depth of cut can be adjusted in a simple manner by varying the position of the setting element 13, to which the knife 15 is attached, within the groove 17. At the end of the holding device 11 facing away from the guide part 21, a feeler element 27 is provided, which cooperates with a controller 29 of the cutting device 1, which is followed in the following which will be discussed in more detail.

In this exemplary embodiment, the controller 29 is designed as a cam controller, which comprises a contour disk 31, also referred to as a cam disk, which is essentially circular and whose center lies on the center 9 of the movement path 7 of the closure 3. The contour disk 31 has a fixed position and rotates when the holding device 11 is displaced and the closure 3 not with, but remains in the position shown in Figure 1. The contour disk 31 has a curved outer contour 33, which is scanned by the sensing element 27 of the holding device 11, which is displaceably mounted in the direction of the longitudinal central axis 20. As a result, the holding device 11 is positively guided when it rotates around the center 9 and is displaced along a contour path, the course of which corresponds to the outer contour 33 of the contour disk 31.

The contour disk 31 has a partial section 35.1 which extends over a circumferential region of approximately 110 ° and is designed as a circular path section. The section 35.1 is adjoined — as seen in the direction of displacement of the holding device 11 and the closure 3 (arrow 37) - by a section 35.2 which extends over a circumferential area of approximately 140 ° and is likewise designed as a circular section, the radius of which is smaller than the radius of subsection 35.1. A third subsection 35.3 adjoins subsection 35.2, which extends over a circumferential area of approximately 35 °. The radius of the contour disk 31 in the area of the section 35.3 is larger than the radius both in the area of the section 35.2 and in the area of the section 35.1. The transition area from subsection 35.3 to subsection 35.1 has an inwardly curved, that is to say concave profile, as seen in the direction of the center 9. The transition from one section to the other extends over a relatively large circumferential area of the contour disk 31 and shows no sharp edges and jumps. By designing the transitions, the displacement acceleration with which the holding Device 11 is displaceable relative to the movement path 11 can be set.

In the event of a displacement, that is to say rotation of the holding device 11 in the direction of the arrow 37 about the center point 9 by means of a guide device (not shown), the distance thereof and thus the distance between the knife 15 and the movement path 7 of the closure 3 are changed due to the forced guidance by the feeler element 27. In the peripheral regions of the contour disk 31 with a constant radius, that is to say in the subsections 35.1, 35.2, 35.3, the holding device 11 is at a constant distance from the movement path 7 of the closure 3.

The function of the cutting device 1 is explained in more detail below with the aid of a cutting process: The closure 3 is transferred in position A from a processing station (not shown) for the closure 3 to the cutting device 1. As shown in Figure 1, the closure 3 is introduced into the semicircular recess 23 of the guide part 21 of the holding device 11 and centered. In this position, the side surface 25 of the guide part 21 lies on the movement path 7. Then the closure 3 and the holding device 11 are displaced together in the direction of the arrow 37, the closure 3 along the movement path 7 and the holding device 11 along the through the outer contour 33 of the Contour disk 31 predetermined contour path. Because of the smaller radius ^{1 of} the contour disk 31 in the area of the section 35.2 compared to the section 35.1, the holding device 11 is displaced relative to the movement path 7 of the closure in the direction of the center 9. The distance between the holding device device 11 and the movement path 7 is enlarged such that the guide part 21 releases the closure 3, that is, the closure 3 fixed by the holder (not shown in FIG. 1) is guided outside the effective range of the recess 23. In the area between the position B and the position D, the closure 3 and the holding device 11 are at a constant distance from one another. In the transfer area between position B and position D, the closure 3 can be machined, preferably at least one vertical incision is made in the region of the closure circumference, in which the guarantee ring is subsequently formed by a circumferential cut.

The cut running in the circumferential direction of the closure 3 is made in the region of the partial section 35.3. In this section, the holding device 11 is displaced outward in the direction of the movement path 7, so that the closure 3 is guided in the recess 23 of the guide part 21, the distance between the closure 3 and the knife 15 projecting into the recess 23 being so small is that the cut can be made in the circumference of the closure 3. For this purpose, the closure 3 is rotated in the region of the partial section 35.3 at least by 360 ° about its central axis 5, as a result of which a cut is made in the circumferential direction of the closure 3. Because the contour disk 31 has a constant radius in the region of the partial section 35.3, the distance between the closure 3 and the knife 15 is constant during the 360 ° rotation, and thus also the depth of the cut. The closure 3 is then guided out of the cutting device 1 in the position F. FIG. 2 shows an exemplary embodiment of a holder 39 for the closure 3, which has a pin-shaped holding element 41 and a gearwheel 43 connected to it in a rotationally fixed manner. The gear 43 cooperates with a drive device, not shown, by means of which the rotational speed of the closure 3 can be adjusted about its central axis 5. The rotational speed of the shutter 3 is in the range of the section 35.3 at least so high that ^"it performs a 360 ° rotation, is introduced whereby the running in the circumferential direction section.

In a further embodiment (not shown), the cutting device 1 described with reference to FIG. 1 has a plurality of holding devices 11, each with at least one knife. As a result, their throughput, that is to say the number of closures processed by the cutting device, can be increased. It is also advantageous that the use of several knives increases their service life and thus the maintenance intervals of the cutting device, in which the knives that are subject to wear are exchanged. In each case a closure and a holding device having a knife are guided together from the inlet (position A) of the cutting device to the outlet (position F), that is to say they have the same rotational speeds.

The knife 15 attached to the adjusting element 13 is preferably designed as an interchangeable cutting plate, so that when the knife wears it can be replaced easily and quickly. In the exemplary embodiment shown in FIG. 1, the knife 15 has a straight cutting edge on, which is aligned purely as an example tangential to the circumference of the closure. In order to make a cut with a constant depth in the circumference, the knife can also be inclined at an acute or obtuse angle with respect to the closure.

In summary, it should be noted that the cutting device 1 can be used to make an exact cut running in the circumferential direction of a closure, thereby preferably forming a guarantee ring, also known as a guarantee band. The depth of cut is determined by the contour disk 31, which controls the relative movement of the holding device 11 with respect to the movement path 7 of the closure 3. With the aid of the setting element 13, to which the knife 15 is attached, the cutting depth can be finely adjusted, for example to compensate for tolerances of the individual device parts. During the cutting process, the distance between the knife and the closure is constant, so that the cut has a constant depth over the entire circumference of the closure, whereby the tamper-evident function of the guarantee ring can be guaranteed with a high degree of certainty. It can also be seen, moreover, that cuts which run in the circumferential direction and are not completely circumferential, that is to say closed, are also made in the closures. To achieve this, it is only necessary to limit the rotary movement of the closure, which is located in the partial area 35.3, for example to 120 °, 240 ° or the like.

Expectations :

1. Device for introducing a cut running in the circumferential direction of a plastic closure, with at least one knife held by a holding device and with a holder for the closure, characterized in that the holding device (11) with respect to a movement path

(7) of the closure (3) by means of a control (29) is displaceable, that the closure (3) is rotatably mounted about its central axis (5), and that by rotating the closure (3) about its central axis (5) Cut can be introduced, the distance between the closure (3) and knife (15) being constant or substantially constant during the rotation.

2. Cutting device according to claim 1, characterized in that the movement path (7) is a circular path and that the holding device (11) holding the knife (15) can be displaced along a preferably closed, curved contour path, the center point of which is on the center point (9) the circular path.

3. Cutting device according to claim 2, characterized in that the rotational speed of the closure (3) and that of the knife (15) is the same or substantially the same. 4. Cutting device according to one of the preceding claims, characterized in that it has a plurality of holding devices (11), each with at least one knife (15).

5. Cutting device according to one of the preceding claims, characterized in that at least a partial section (35.1, -35.2; 35.3) of the contour path is a circular path section.

6. Cutting device according to one of the preceding claims, characterized in that the control (29) is a cam control with a contour disc (31) which can be scanned by a contact element (27) cooperating with the holding device (11).

7. Cutting device according to claim 6, characterized in that the feeler element (27) is connected to the holding device (11).

8. Cutting device according to one of the preceding claims, characterized in that the holding device (11) comprises a guide part (21) with a preferably semicircular recess (23) for the closure (3).

9. Cutting device according to one of the preceding claims, characterized in that the knife

(15) protrudes into the recess (23).

10. Cutting device according to one of the preceding claims, characterized in that the cutting depth of the knife (15) is adjustable. 11. Cutting device according to one of the preceding claims, characterized in that the position of the knife (15) relative to the closure (3) is adjustable.

Claims

CHANGED CLAIMS [received at the International Office on May 27, 1999 (May 27, 1999); original claim 1 replaced by new claim 1; all other claims unchanged (1 page)] New claim 1

1. Device for introducing a cut running in the circumferential direction of a plastic closure, with at least one knife held by a holding device and with a holder for the closure, the closure being rotatably mounted about its central axis, and the cut by rotating the closure about its central axis can be introduced, characterized in that the closure (3) can be guided along a movement path (7), that the holding device (11) can be displaced relative to the movement path (7) by means of a control (29), and that the holding device (11) can also be moved the closure (3) can also be moved.