Package making – Methods – Forming or partial forming a receptacle and subsequent filling
Reexamination Certificate
1999-11-10
2001-10-30
Vo, Peter (Department: 3721)
Package making
Methods
Forming or partial forming a receptacle and subsequent filling
C053S478000, C053S559000
Reexamination Certificate
active
06308500
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a sealing tool and a process for sealing a package trough with a covering film.
Packages, particularly packages for foods, are becoming increasingly important today in the preservation of foods. For packaging, the foods are placed in a so-called package trough and the package trough is then closed in a gas-tight manner with a covering film by sealing the covering film onto the edge of the package trough.
Usually, the package troughs are semi-continuously sealed with a covering film in so-called sealing stations. To this end, the package trough filled with the packaged good and the covering film are initially fed into the sealing station. As soon as the package trough is situated in the sealing station, a first bottom sealing tool is raised vertically from below and pressed against a second, heated top sealing tool, which is located above the covering film. As a result of the pressure and temperature applied, the covering film and the edge of the package trough, which are situated between the sealing tools, are sealed. In order to obtain gas-tight seal seam, it is important that the seal seam have a certain width and that the seal seam be essentially situated in the middle of the edge of the package trough. After sealing, the first sealing tool is lowered back beneath the freshly sealed package trough, and the sealed package trough is fed on to the cutting station.
Although this type of a sealing station has been in use for many years, it nevertheless displays a number of disadvantages. For instance, package troughs having an undercut cannot be sealed with such a sealing tool, because the first sealing tool collides with the undercut during lifting and lowering and thereby destroys it. However, even with packages that do not have an undercut, problems repeatedly occur during the sealing of heavily loaded package troughs, because these package troughs sag. Because of this sagging, the package troughs tilt and the first sealing tool on its ascent collides with the corners and thereby destroys or deforms them.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a device by which a package trough having an undercut can be sealed and which does not show the other disadvantages of the prior art.
According to the present invention, this object is achieved by providing a bottom sealing tool for sealing a package trough with a covering film, in which the sealing tool comprises a bottom part, side parts oriented transverse and side parts oriented parallel to the direction of package trough feed, wherein the side parts oriented transverse to the direction of package trough feed can be displaced downwardly, while the other parts of the bottom sealing tool are fixed in their spatial arrangement relative to the frame of the machine.
In the meaning of the invention “fixed in their spatial arrangement relative to the frame of the machine” does not mean that the part has to be in a totally rigid arrangement. It may, in fact, move by several millimeters.
Preferably, the side parts oriented transverse to the direction of package trough feed can be displaced vertically downwardly.
In another preferred embodiment, the side parts that do not change their position relative to the frame of the machine have on their top a surface with a low coefficient of friction. This surface can either be polished or coated with Teflon® or a similar material.
Preferably, the side parts oriented parallel to the direction of the package trough feed taper downwardly from the top to the bottom, so that package troughs having one or more undercut(s) oriented parallel to the direction of package feed can be sealed with the parts.
Another bottom sealing tool according to the present invention preferably serves the purpose of sealing at least two adjacent package troughs. In addition to the bottom part, the side parts oriented transverse and the side parts oriented parallel to the direction of package trough feed, such a sealing tool also has at least one middle part, wherein the side parts oriented transverse to the direction of package feed can be displaced downwardly, while the other parts of the bottom sealing tool are fixed in their spatial arrangement relative to the frame of the machine.
Preferably, the side parts oriented transverse to the direction of package trough feed can be displaced vertically downwardly.
In yet another preferred embodiment, the middle parts and the side parts oriented parallel to the direction of package trough feed have on their top a surface with a low coefficient of friction. This surface can either be polished or coated with Teflon® or similar material. Preferably, the middle part and/or the side parts oriented parallel to the direction of package trough feed taper downwardly from the top to the bottom so that package troughs having one or more undercut(s) oriented parallel to the direction of package trough feed can be sealed with the parts.
Another object of the present invention is to provide a process for sealing package troughs that does not show the disadvantages of the prior art.
According to the present invention, this object is achieved by providing a process for sealing a package trough with a covering film by using the bottom sealing tool according to the present invention, wherein:
the covering film and the package trough are fed into the sealing station and optionally fixed and pressed between the bottom sealing tool and the top sealing tool, heated and thereby sealed;
the displaceable parts of the bottom sealing tool are lowered; and
the finished package is moved on.
In a preferred embodiment of the process according to the present invention, the displaceable parts of the bottom sealing tool are displaced vertically downwardly.
An advantage of the present invention is that a package trough having one or more undercuts oriented parallel to the direction of package trough feed can be sealed with a covering film. Another advantage of the invention is that heavily loaded package troughs are supported by the side part and/or middle part which is/are fixed in its/their spatial arrangement and which therefore no longer sag(s), so that the sealing tool no longer destroys the package trough during its ascents and descents.
REFERENCES:
patent: 4372098 (1983-02-01), Mason
patent: 5014500 (1991-05-01), Robache
patent: 5163269 (1992-11-01), Williams
patent: 5307610 (1994-05-01), Schneider et al.
patent: 1135817 (1963-03-01), None
patent: 59 503 (1967-12-01), None
patent: 43 36 274 C2 (1995-10-01), None
Blöcher Rolf
Inverardi Celestino
Thomas Ulrich
Akin Gump Strauss Hauer & Feld L.L.P.
Tawfik Sam
Tiromat Kramer +Grebe GmbH & Co. KG
Vo Peter
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