Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
2000-10-11
2001-07-17
Lazarus, Ira S. (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S477000, C053S476000, C053S329200
Reexamination Certificate
active
06260334
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a sealing tool for sealing a package trough with a covering film.
Packages, particularly for foods, are becoming increasingly important today in making foods durable. For packaging, the foods are placed in a so-called package trough and the package trough is then closed gas-tight with a covering film by sealing the covering film onto the edge of the package trough.
As a rule, 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 product 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 located above the covering film. As a result of the pressure and temperature, the covering film and the edge of the package trough, which are situated between the sealing tools, are sealed. In order to obtain a gas-tight seal seam, it is important that the seal seam has a specific width and that the seal seam is 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 sealing station has been in operation for several years, it nevertheless displays a number of disadvantages. For instance, package troughs with an undercut cannot be sealed with such a sealing tool because the first sealing tool collides with said undercut during lifting and lowering and destroys it. However, even on packages without an undercut, problems repeatedly occur during the sealing of heavily loaded package troughs because the package troughs sag. Because of this sag, the package troughs turn askew and the first sealing tool on its ascent collides with their corners and destroys or deforms them.
SUMMARY OF THE INVENTION
The object is therefore to provide a device by means of which a package trough with an undercut can be sealed and which does not have the other disadvantages of the prior art.
According to the invention, sa id object is achieved by providing a bottom sealing tool for sealing a package trough with a cove ring film, which consists of a bottom part, side parts oriented transversely and side parts oriented parallel to the direction of package trough feed, wherein at least one side part oriented parallel to the direction of feed is fixed in its spatial position in relation to the machine frame whereas the other parts of the matrix can be displaced vertically downwards.
In the meaning of the invention, “fixed in its spatial position in relation to the machine frame” does not imply that the part must be in a totally rigid arrangement. In fact, it may move by several millimeters.
Both the side parts oriented parallel to the direction of feed are preferably fixed in their spatial position in relation to the machine frame.
In another preferred embodiment, the side parts remaining unchanged in their position in relation to the machine frame have on their top a surface with a low coefficient of friction. This surface can be either polished or coated with Teflon or a similar material.
The side parts fixed in their spatial position preferably taper downwards so that package troughs having one or more undercuts oriented parallel to the direction of package feed can be sealed with said parts.
A sealing tool according to the invention is used preferably to seal at least two adjacent package troughs. In addition to the bottom part, the side parts oriented transversely, and the side parts oriented parallel to the direction of package trough feed, such a sealing tool also has preferably at least one middle part which is fixed in its spatial position in relation to the machine frame.
The side parts of such a sealing tool are also preferably fixed in their spatial position in relation to the machine frame.
In another preferred embodiment, the middle parts and the side parts remaining unchanged in their position in relation to the machine frame have on their top a surface with a low coefficient of friction. This surface can be either polished or coated with Teflon or a similar material.
The middle part and/or the side parts fixed in their spatial position preferably taper downwards so that package troughs having one or more undercut(s) oriented parallel to the direction of package feed can be sealed with said parts.
Another object of the present invention is to provide a process for sealing package troughs which does not have the disadvantages of the prior art.
According to the invention, said object is achieved by providing a process for sealing a package trough with a covering film using the sealing tool of the 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 vertically displaceable parts of the bottom sealing tool are lowered vertically, and
the finished package is moved on.
The 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 and/or middle part fixed in its spatial position and thus no longer sag, with the result that the sealing tool no longer destroys the package trough during its ascents and descents. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be illustrated in the following with reference to
FIGS. 1
to
6
. This is merely an explanation by way of example and thus does not limit the invention.
FIGS. 1
a
and
1
b
show a package with an undercut.
FIGS. 2
a
and
2
b
show a sealing tool according to the invention for sealing a package trough with a covering film.
FIGS. 3
a
and
3
b
show a sealing tool according to the invention for sealing two package troughs with a covering film.
FIG. 4
shows a cross section of the sealing tool according to the invention for sealing three package troughs.
FIG. 5
shows the lowering mechanism for the sealing tool.
FIG. 6
shows a sealing station with the sealing tool according to the invention.
REFERENCES:
patent: 5014500 (1991-05-01), Robache
patent: 5241801 (1993-09-01), Nelson
patent: 5307610 (1994-05-01), Schneider et al.
patent: 5765343 (1998-06-01), Whittaker
patent: 59 503 (1967-11-01), None
patent: 90 06 292 (1990-10-01), None
patent: 195 41 983 A1 (1997-05-01), None
Blöcher Rolf
Inverardi Celestino
Thomas Ulrich
Akin Gump Strauss Hauer & Feld L.L.P.
Lazarus Ira S.
Tawfik Sam
Tiromat Krämer & Grebe GmbH & Co. KG
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