Package making – Methods – Filling preformed receptacle and closing
Reexamination Certificate
2003-10-10
2004-11-23
Kim, Eugene (Department: 3721)
Package making
Methods
Filling preformed receptacle and closing
C053S051000, C053S064000, C053S398000, C493S010000, C493S011000, C493S013000
Reexamination Certificate
active
06820399
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for positioning webs of film of a packaging device, according to which goods are introduced in a first web of film moving in the advance direction in troughs in this first web of film and then a second web of film is withdrawn from a supply of web against the resistance of a brake and is placed on the first web of film and bound with the same with the advance of the second web of film downstream of the supply of web being detected by a recognition means and set by varying the brake force of the brake in dependence on the signal from the recognition means so that in each case a repeat as a defined area of the second web of film comes to lie on the troughs in the first web of film. In addition, the invention relates to a packaging device for the performance of this method.
A method of this kind or a packaging device of this nature is generally known. Here, the first web of film is provided with the troughs into which the goods to be packed are introduced. Then, the second web of film is placed on this first web of film provided with the goods and welded thereto, either using vacuum technology or with inclusion of air, for example in a sealing station. Subsequently, the individual troughs with the surrounding area of film are separated from each other and in this way individual items of goods packages are produced. This packaging method is frequently used for foodstuffs, but may also be used for other goods. For the inscription of the packaging, generally the second web of film is imprinted, with this frequently taking place completely so that, for example, the packed goods may be protected against UV light. The imprint is divided into repeats according to the packaging length so that one repeat comes to lie over each trough.
For purposes of appearance and to guarantee an airtight welding, the top, second web of film is preferably under tension so that no folds occur during the later packaging. For this, the second web of film is withdrawn from a supply, which may, for example, be formed from a roll, against the restraining force of an adjustable brake. The second web of film, which is under tension, is then placed on the first web of film by means of guides and then welded, whereby adjustment of the brake force may be used to set the position and extension of the flexible web of film. In practice, for example, the imprint should be performed so the desired image only appears after a certain pretension of the second web of film.
The position of the individual repeats is detected by a recognition means, whereby a regulator may be used to set the brake force so that the rate of advance of the second web of film may be matched to that of the first web of film.
SUMMARY OF THE INVENTION
Although this is adequate for the general control of packaging machines, it has been found that slight positional deviations are frequently possible so that the repeats do not come to lie one hundred percent exactly over the troughs. In particular with packaging which is to be printed right up to the edge, this has been found to be disadvantageous since, on the one hand, the goods packaged in this way give a poorer impression of quality and, on the other, the positional deviation may mean that necessary information is no longer on the actual packaging, but is cut off during the later cutting process and so the goods are no longer marketable. For example, information such as the use-by date of a foodstuff or the weight must under no circumstances fall out of the area of the later packaging.
Therefore, it is the object of the invention to create a method for the positioning of the web of film and a packaging device for the exact and simple positioning of the repeats of the second web of film over the troughs of the first web of film.
This object is achieved according to the invention in that a second recognition means determines the exact position of the repeat relative to the first web of film and, in the event of dimensional errors, adjusts the position of the first recognition means relative to the direction of conveyance of the second web of film.
By way of the embodiment of the packaging method according to the invention, it is now possible to define an exact position by means of the second recognition means. If it is hereby determined that the position deviates from the set position, a regulating intervention will be performed by means of changing the position the first recognition means.
By way of the embodiment according to the invention it may be achieved that, by means of the control of the actual condition by the second recognition means, the position of the first recognition means is changed relative to the direction of conveyance of the second web of film. The result of this is that, due to the control circuit comprising the first recognition means and the brake force, the control circuit is correspondingly influenced. For example, if the second recognition means determines that the repeat is slightly ahead of the required position, i.e. has come to lie slightly ahead of the troughs, the front part of any printed image applied would be cut off. In this case, the position of the first recognition means is oriented backwards, which means changed against the direction of conveyance of the second web of film whereby the first recognition means records the repeat correspondingly earlier and then actuates the brake correspondingly more powerfully in order, by means of withdrawing less of the second web of film, to correct the position of the second web of film over the first web of film as appropriate.
The suggested method is in particular performed with packaging devices which operate fully automatically. However, the method is suitable in the same way, to be used in other manufacturing processes, for example, which in particular involve positioning two films one on the other. Usually, the first web of film, which takes the goods to be packaged, is described as the bottom web and the second web of film, which seals the troughs, is usually described as the top web.
The suggestion according to the invention achieves a self-adjusting system. When setting the machine, the top web no longer needs to be arranged with high precision in relation to the bottom web since the two recognition means in conjunction with the stepped intervention in the control circuit in question and the brake and the film's intrinsic elasticity achieve the relevant positioning of the top web on the bottom web. Therefore, the process runs fully automatically.
However, the suggestion according to the invention not only accelerates a format change, the amount of adjustment work required is reduced by the suggestion according to the invention, it also provides greater stability during the operation, since it is been found that the tensile stress of the web of film withdrawn from a supply of web is not always identical during the process. For example, after production, the film is wound on a reel whereby once again the web is slightly stretched or wound on under tension. This dimension is not always identical along the direction of conveyance which means that a certain offset of the repeat takes place, even if the repeat was aligned exactly on the trough at the start. This effect is also automatically compensated by the suggestion according to the invention. As a result, the invention achieves less manual or personal positioning work when changing a web of film and higher stability, i.e. constant packaging quality.
Due to its intrinsic elasticity, the web of film may be offset to a certain degree by actuating the brake or releasing the brake so that on a relevant signal from the first recognition means, the controller may perform a control intervention. If the second optical recognition means recognises a positional deviation of the repeat of the second web of film relative to the trough in the first web of film, the first recognition means is slightly offset in such a way that the brake is either (slightly) released or prematurely applied more powerfully. If the b
CFS Germany GmbH
Desai Hermant M
Kim Eugene
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