DE102008020800B4 - Closure device for closing or closing and separating a packaging web - Google Patents

Abstract

The invention relates to a method for closing and / or separating a packaging web (22), in particular tubular bag film, with a closure device having two closure jaws (6) which are arranged on a respective closure jaw carrier (8), the method comprising the following steps:
a) positioning the closure jaws (6) in a starting position,
b) closing the closing jaws (6) so that they rest against one another,
c) pulling the packaging web (22) and moving the adjoining sealing jaws (6) in a direction of passage (F) at a throughfeed speed, for closing and / or separating the packaging web (22),
d) releasing the closing jaws (6),
e) returning the closure jaws (6) to the starting position,
f) repeating steps b) to f).

Description

The invention relates to a closure device for closing or closing and separating a packaging web, in which products are located, with a feed device and a removal device and two closure jaws, which are each arranged on a rotatably mounted about a shaft closure jaw carrier, and a parallel to the Axis extending back rotation axis are rotatably arranged eccentrically in the closure jaw carrier.

From the EP 1 810 922 A1 For example, a device for packaging articles in a wrapping film is known. For this purpose, the objects are guided on a circulating conveyor belt successively substantially at a constant speed under a welding device. The welding device has at least one welding drum with at least one welding bar and a counter-drum with at least one counter-bar. The drums are driven rotating against each other. With these drums, the film is sealed and separated between two objects in an empty space when passing through a welding path. The welding drum and the counter drum are dynamically driven by a servomotor.

Methods and devices for closing or closing and separating a packaging web, in particular of tubular bags, have long been known and are used in industry in large numbers, for example, to pack products in foil. For example, these products are positioned in a tubular bag machine in a film tube, which is then welded together and separated between the products.

Conventionally, the packaging web with the products contained therein is guided between two, for example, horizontally arranged closing and / or separating jaws. At the point where the packaging web is to be closed and / or separated, the promotion of the products and the surrounding packaging web is stopped and the two sealing and / or separating jaws are closed, so that they then abut each other and the packaging web between them pinch. If the product is packed with foil, the closing jaws can be heated, for example, in order to ensure a thermal welding of the foil. At the same time, the packaging web can be separated at the just closed point in this step, so that the products are individually packaged when they leave the closure device.

The disadvantage is that a certain amount of time is necessary for closing the packaging web, for example for welding the film. During this time, no further transport of the products can take place, which significantly increases the processing time and thus significantly reduces the amount of products to be packaged by a conventional system per unit of time. In addition, it can come by the constant startup and deceleration of the products on the conveyor belt, which passes the products through the closure jaws, that in particular fall over high and slim products on the conveyor belt.

From the DE 38 22 915 A1 For example, an automatic welding method is known in which a continuous, tubular film running at a substantially constant speed is welded at regular intervals in a direction transverse to the direction of travel with a welding unit arranged transversely to the path of the tubular film, the Welding unit at substantially the same speed as the tubular film is moved at least during a time interval over which the welding unit is in contact with the tubular film.

The welding unit is formed by rollers arranged transversely over the film web. By suitably controlling the rotational speed of the rollers, it is achieved that the welding surfaces move at substantially the same speed as the film during the welding operation. The rollers themselves are arranged stationary.

The invention has for its object to improve the closure device described above for closing or closing and separating a packaging web to the effect that abutting closure jaws, the trapped between them packaging web in the forward direction, so that the film is always stretched, and in the the feeding device and the removal device can be separated from one another and the products can be transported safely over the intermediate space which forms between them.

To solve the problem, a generic closure device characterized by the fact that each closure jaw carrier is designed in the form of a substantially circular disc, that on each closure-back support a teilzylindrisch trained conveying element is concentrically arranged, and that the radius of the conveying element is smaller than the radius of the Closing jaw carrier, so that a product that is in the Closing device is located, rests on the closure jaw carriers.

• a) Positionieren der Verschlussbacken in einer Ausgangsposition,
• b) Schließen der Verschlussbacken, so dass diese aneinander anliegen,
• c) Ziehen der Verpackungsbahn in einer Durchlaufrichtung mit einer Durchlauffördergeschwindigkeit mittels der aneinander anliegenden Verschlussbacken, zum Verschließen und/oder Abtrennen der Verpackungsbahn,
• d) Lösen der Verschlussbacken,
• e) Rückführen der Verschlussbacken in die Ausgangsposition,
• f) Wiederholen der Schritte b) bis f).

The procedure for closing or closing and separating the packaging web comprises the following steps:

• a) positioning the closure jaws in a starting position,
• b) closing the closing jaws so that they abut one another,
• c) pulling the packaging web in a direction of passage at a throughfeed speed by means of the abutting closure jaws, for closing and / or separating the packaging web,
• d) releasing the closing jaws,
• e) returning the closure jaws to the starting position,
• f) repeating steps b) to f).

By rotation of the closure jaw carrier, the method step b), the closure of the closure jaws, can be carried out. Further rotation of the closure jaw carrier ensures that the adjoining closure jaws pull the packaging web clamped between them forward in the direction of passage. For this purpose, the rotational speed of the closure jaw carrier must be adapted to the throughfeed speed of the feed and removal device. The release of the closure jaws in process step d) is carried out by further rotation of the closure jaw carrier, through which the closure jaws are returned to the starting position d).

It is particularly advantageous that each closure jaw carrier is designed in the form of a substantially circular disc, on which in each case a closure jaw is arranged rotatably eccentrically about a jaw rotation axis which runs parallel to the carrier rotation axis. By way of an electrical or electronic control of the closure device, the rotational speed of the closure jaw carriers about the carrier rotational axes and the rotational speed of the closure jaws about the jaw rotation axes are adjustable so that the closure jaws always face each other and do not rotate relative to each other.

On each closure jaw carrier, a part-cylindrical conveying element is arranged concentrically with a radial recess, in the recess of which the closing jaw is arranged. These part-cylindrical conveying elements are designed so that they support the further transport of the products and the surrounding packaging web when the closure jaws are already released and returned to their original position. The distance between the two conveyor elements corresponds to the width of the products to be packaged. In order to keep this distance constant during operation of the device, the part-cylindrical conveying elements are arranged concentrically on the closure jaw carrier.

In addition, the radius of the conveying element is smaller than the radius of the closure jaw carrier. This ensures that a product, which is located in the closure device, rests on the closure jaw carrier. The radius of the conveyor element used depends on the width of the products to be packaged. Particularly advantageously, the conveying element is easily interchangeable, so that when switching to another product to be packaged with a different product width simply a conveyor element with an adapted radius is used.

Preferably, a friction element is located radially outside the conveying element on at least one of the closure jaw carriers. This friction element increases the static friction between a product resting on the closure jaw carrier and the closure jaw carrier. Such a friction element is designed, for example, as a rubber element applied to the closure jaw carrier. The size of this conveying element depends on how long the first predetermined time interval .DELTA.t used in the method is _fast , since only during this period of time a product resting on the closure jaw carrier can be conveyed in the direction of passage.

After the closure jaws are positioned in the starting position, they are closed. They clamp between them to be closed or to be closed and to be separated packaging web. In the case of a film packaging, the closure jaws are heated, so that there is a thermal welding of the two film layers. After the closing jaws are closed and the packaging web is clamped, the closing jaws are moved in the flow direction in which the products pass through the closing jaws. This is done with the continuous conveying speed with which the products are also conveyed to and from the closing jaws. The closure jaws are in this way long enough to each other, for example, to weld two film webs together without the promotion of the products would have to be interrupted by the closure jaws. Thus, both a positive and a negative acceleration of the products is prevented, ensuring a significant increase in stability. In addition, the fact that the products no longer have to be stopped To close the packaging web, the processing time significantly reduced, so that a significantly larger number of products can be enforced. As a result, both the time required and the production costs are significantly reduced.

Since the closing jaws naturally run over the entire cross-sectional area of the packaging web to be closed, a conveying device which conveys the products through the closing jaws must be interrupted at the location of the conveying jaws themselves. This is conventionally solved by a conveyor belt conveying the products to the closure jaws and another conveyor belt receiving the products after passing through the closure jaws. In the closure device according to the invention, the closure jaws move with the products. The distance at which no conveyor can be present, therefore, is significantly greater than in conventional approaches. The transport of the packaging web and the products contained therein is therefore ensured by the closure jaws themselves. The fact that they are moved in the closed state in the direction of passage, they pull the packaging web and thus the products contained therein forward.

After the packaging web has been closed and optionally separated, the closing jaws are opened again and then returned to their original position, where the process begins again. Preferably, the packaging web is welded. For this purpose, a heating device or a heating wire can be provided in at least one closing jaw. The time in which the closed closure jaws are conveyed together with the packaging web is sufficient to weld and cut the film.

Advantageously, when returning the closure jaws to the starting position, a product located in the packaging web is conveyed further in the direction of passage.

Particularly advantageously, the product is transported directly to the removal device.

This conveying of the products takes place by means of at least one of the closure jaw carriers, which is preferably configured such that a product located in the packaging web rests on the contract jaw carrier, while the closure jaws themselves are already loosened and are conveyed back to the starting position.

Advantageously, the speed of the closing jaw carriers in the return of the sealing jaws to the initial position at least for a first predetermined period of time At is _quickly greater than the throughput conveying speed. The result of this is that a product resting on the closure jaw carrier is conveyed faster than the next product located in the packaging web in front of the closure jaws. The packaging web or film located between the two products is stretched so that a closure is possible simply and safely without unwanted wrinkling.

Advantageously, the conveying of the product by the closure jaw carrier takes place during the return of the closure jaws to the starting position with slippage. The closure jaw carrier rotates, for example, under the product that it conveys in the direction of passage. This is particularly advantageous if the distance to be traveled by the closure jaws is greater up to the starting position than the distance between two intended closure points of the packaging web. In addition, the products are pressed only by their own weight on the closure jaw carrier, so that in particular for light products in this way a maintenance of the continuous conveying speed can be achieved.

Preferably, the speed of the closing jaw carriers in the return of the sealing jaws to the initial position after this first predetermined time period .DELTA.t is _fast for a second predetermined period of time .DELTA.t _slowly less than the throughput conveying speed. In the first predetermined period Δt _fast , the product resting on the closure jaw carrier is conveyed further in the direction of a removal device. After this first predetermined period of time, the product has reached the removal device and is transported by this further. Now, if the remaining way that the closure jaws have to travel back to their starting position, smaller than the distance that has to cover the packaging web to get to the next closure point, in this way, for example, the speed of the closure jaws by the speed of the closure jaw carrier adjusted so that the closing jaws are closed again at the next scheduled closure point.

In particular, the closure jaw carriers are _slowly stopped during this second predetermined period Δt.

With the aid of a drawing, an embodiment of the invention will be explained in more detail below. Show it

1a to 1e schematic representations of the procedure in a closure device according to the invention in a plan view,

2 the use of a closure device according to the invention in a tubular bag machine in a plan view and

3 a side view of the bag machine 2 ,

The 1a to 1e show schematically the procedure in a closure device according to the invention. The flow direction in pictures 1a to 1e is from left to right. About feeder belts 2 become products 4 to closing jaws 6 transported. The closing jaws 6 are each on a closure jaw carrier 8th rotatably mounted, which in turn is rotatable about an axis A. On each of the closure jaw carriers 8th there is a part-cylindrical trained conveying element 10 , The radius of the conveyor element 10 is smaller in the figures shown than the radius of the formed as a substantially circular disc closure jaw carrier 8th , On the right side go through the products 4 a removal device 12 ,

In 1a are the closing jaws 6 in a starting position. The two closure jaw carriers 8th rotate, the upper counterclockwise, the lower clockwise, and so lead the two closing jaws 6 towards each other. This is 1b shown.

The rotation of the two closure jaw carriers 8th is aware of the gaps between the products 4 , which are in a packaging web, not shown, so tuned that the closure jaws 6 between two products 4 to move towards each other. Simultaneously with the rotation of the closure jaw carrier 8th The closing jaws also rotate about the axis A. 6 in each case a back-rotation axis.

Here is the rotational speed of the closing jaws 6 on the rotational speed of the closure jaw carrier 8th tuned so that the two closing jaws 6 always oriented the same way to each other and perform no relative rotation against each other.

In 1c are the closing jaws 6 already closed and by rotation of the closure jaw carrier 8th continued to the right. The adjoining closing jaws pull 6 on the packaging web, which the products 4 envelop and pull so that just in front of the closing jaws 6 located product 4 on the closure jaw carrier 8th ,

In 1d is shown that the closing jaws 6 to open again. Because the two closing jaws 6 in adjoining condition with the products 4 There was plenty of time, the packaging line 22 to close or close and separate.

In 1e become the closing jaws 6 returned to their original position. You can see that between the conveyor elements 10 located product 4 neither contact to the feed belt 2 still to the removal device 12 Has. As a result, both will not benefit from it. This happens in 1e in that firstly the product 4 on the closure jaw carriers 8th and secondly by the fact that the conveying elements 10 on the product 4 and drive it forward as well. Especially for light products 4 , which rest only with relatively little weight on the closure jaw carriers, it is advantageous, the rotational speed of the closure jaw carrier 8th increase in this step of the process and thus the constant throughput of the products 4 to ensure. For this it is advantageous that on the surface of the closure jaw carrier 8th a friction element is arranged, which may be formed for example in the form of a rubber ring or rubber studs. Such a friction element is in the 1a to 1e Not shown. The closure jaw carrier 8th transport the product resting on them with the help of the conveying elements 10 so long in the direction of the removal device 12 until the product 4 rests there and from the removal device 12 is further promoted. This is in 1a shown. From this moment, the rotational speed of the closure jaw carrier 8th be reduced if the way the following product is on its way between the closing jaws 6 is greater than the way the closing jaws 6 have to cover themselves. In this way it is ensured that the closing jaws 6 always between two products 4 shut down.

It is also conceivable on every closure jaw carrier 8th more than a closure jaw 6 to arrange, approximately radially opposite. In this case would have to between the two closing jaws 6 on a closure jaw carrier 8th two conveyor elements 10 to be ordered. The radius of the closure jaw carrier 8th in this case, it is to be chosen correspondingly larger. However, this results in an increased space requirement, so that the design with a closure jaw 6 per closure jaw carrier 8th advantageous appears.

Will the in the 1a to 1e shown closure device according to the invention converted to another product, for example, has a different product width and product length, so the conveying elements 10 simply by other conveyor elements 10 be replaced with a different radius. At the same time, the rotational speed of the closure jaw carrier 8th adapted to the new product length.

2 shows a schematic plan view of a tubular bag machine. The passage direction F for products 4 is in 2 left to right. On the left side the products are running 4 on three feed conveyors in the bagger and are of three separation devices 14 in groups of three products 4 divided up. About deflector belts 16 they are brought into a central line and fed to the other stations of the tubular bag machine. About the feeder belts 2 become the products 4 through the film feeder 18 guided. Then they get to the closure jaw carriers 8th on which are the closing jaws 6 are located. A closure jaw 6 has a heating wire, not shown, which is heated after the closure jaws abut each other.

In 2 the situation is shown that the closing jaws 6 already abut each other and the packaging web 22 with the products contained therein 4 in the direction of the removal device 12 pull. After closing the closing jaws 6 the heating wire is energized to heat it to a welding temperature. While the closing jaws with the packaging web 22 are moved in the direction of the removal device, the film web is welded together and then severed, so that they can then be opened again and returned to their original position.

3 shows the in 2 in a plan view of a tubular bag machine in a side view. Again, the direction of passage is from left to right. The products 4 be in a separation device 14 in groups of products 4 split and over more deflection bands 16 placed in a central line and fed to the further processing steps. Only schematically indicated in the further course of the flow direction F, the film feed 18 , about the one of a big role 20 upcoming slide 22 to be led. About feeder belts 2 become the groups of products 4 to the closing jaws 6 guided. These are located on a closure jaw carrier 8th , on which also a conveying element 10 for the promotion of products 4 in the direction of the removal device 12 is arranged.

LIST OF REFERENCE NUMBERS

2

infeed

4

product

6

lock jaw

8th

Closing jaw carriers

10

impeller

12

removal device

14

separation device

16

deflection ribbon

18

film feed

20

role

22

Film / packaging web

A

axis of rotation

F

Throughput direction

Claims (8)

Closure device for closing or closing and separating a packaging web ( 22 ), in which products ( 4 ) with a feeding device ( 2 ) and a removal device ( 12 ) and two closing jaws ( 6 ), which are arranged on a respective one about an axis (A) rotatably mounted closure jaw carrier, and about a parallel to the axis (A) extending back rotation axis rotatably eccentric in the closure jaw carrier ( 8th ) are arranged, characterized in that each closure jaw carrier ( 8th ) is formed in the form of a substantially circular disc that on each closure jaw carrier ( 8th ) a part-cylindrical conveying element ( 10 ) is arranged concentrically, and that the radius of the conveying element ( 10 ) is smaller than the radius of the closure jaw carrier ( 8th ), so that a product ( 4 ), which is located in the closure device, on the closure jaw carriers ( 8th ) rests. Closure device according to claim 1, characterized in that each conveying element ( 10 ) is provided with a radial recess in which the closure jaw ( 6 ) is arranged. Closure device according to claim 2, characterized in that on at least one of the closure jaw carrier ( 8th ) radially outside of the conveying element ( 10 ) A friction element is arranged. Closure device according to one or more of the preceding claims, characterized in that in at least one closure jaw ( 6 ) a heating device for welding and separating the packaging web ( 22 ) is provided. Closure device according to one or more of the preceding claims, characterized in that the speed of the closure jaw carrier ( 8th ) when returning the closure jaws ( 6 ) in an initial position for at least one first predetermined time period .DELTA.t is faster than a passage conveying _speed . Closure device according to claim 4 or 5, characterized in that the conveying of the product ( 4 ) happens with slippage. Closure device according to claim 5 or 6, characterized in that the speed of the closure jaw carrier ( 8th ) when returning the closure jaws ( 6 ) is _slowly slower to the initial position after lapse of the first predetermined period Δt for a second predetermined period of time Δt than the flow-through conveying _speed . Closure device according to claim 7, characterized in that the closure jaw carrier ( 8th ) are _slowly stopped during the second predetermined period Δt.

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