Flexible bags – Wall details – Pleated or gusseted
Reexamination Certificate
1998-09-29
2001-07-17
Pascua, Jes F. (Department: 3727)
Flexible bags
Wall details
Pleated or gusseted
C383S107000
Reexamination Certificate
active
06261000
ABSTRACT:
BACKGROUND OF THE INVENTION
Numerous packaging bags and numerous systems for manufacturing them have already been proposed.
For bags of small thickness, that is, those that are generally flat in the filled state, known means generally provide satisfaction. Under such circumstances, the bags are generally formed using two planar sheets that are bonded together along three sides and that are provided with closure means, to example, complementary male/female strips, at the mouth of a bag.
In contrast, until now, manufacturing bags that are intended to receive contents that are thick, has turned out not to be entirely satisfactory, even though a large amount of research has been performed in this very specific field.
In particular, such bags often require lateral bellows which are difficult to make.
Accompanying
FIG. 1
shows, diagrammatically, a known technique for manufacturing bags with lateral bellows by inserting pre-formed bellows
10
between two sheets
12
and
14
that constitute two main faces of the bags, with the bellows being inserted at 90° to the travel direction S of the sheets
12
,
14
. The sheets
12
and
14
are provided with longitudinal male/female closure strips
13
and
15
. The bellows
10
are preferably of varying width, increasing away from the closure strips
13
and
15
so as to enable the bags to be inflated. That known technique does indeed manufacture it possible to make packaging bags having lateral bellows. Nevertheless, it turns out to be quite complex. In particular, the need to insert the bellows
10
at 90° to the travel direction of the sheets
12
and
14
does not enable high manufacturing throughputs to be obtained, and requires insertion of the bellows
10
to be adequately synchronized with the travel of the sheets
12
and
14
.
Document FR-A-2 686 063 describes another technique of manufacturing packaging bags with bellows that consists in preforming a bag with lateral bellows, in splitting the bag over a portion of its length along fold lines external to the bellows, in folding the flaps defined in this way back over the outside of the bag, in placing the closure strips on the flaps, in reforming the bag, and in bonding the closure strips to the flaps that have been put into place. Unfortunately, because of its complexity, that technique does not provide full satisfaction.
The Applicant has also described various alternative solutions for manufacturing packaging bags with lateral bellows in French patent application No. 96 02389 filed on Feb. 27, 1996.
OBJECT OF THE INVENTION
The present invention now seeks to improve known means for manufacturing packaging bags having lateral bellows.
SUMMARY OF THE INVENTION
The foregoing object is achieved in the context of the present invention by a method of manufacturing packaging bags characterized by the fact that it comprises the steps comprising:
forming respective cutouts in each of the two lateral, bellows-forming zones of a packaging bag sheet so that the bag has only two thicknesses superposed at the mouth of the bellows, at least over a portion of its width; and
heat-sealing the adjacent edges of the sheet to the peripheries of the cutouts so as to close the bag.
The present invention also provides apparatus for implementing the method, and bags obtained thereby.
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patent: 7-214702 (1995-08-01), None
Flexico-France
Pascua Jes F.
Schwartz & Weinrieb
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