Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR FABRICATING A BAG WITH A FLAT BOTTOM, AND A
BAG THUS OBTAINED
The present invention relates to a method for
fabricating a bag with a flat bottom and to a bag
thus obtained.
In the field of automatic manufacture of bags,
both bags with handles (shopping bags or shoppers?
and without handles (open-mouthed bags), it is normal
to use as star ting material a continuous tubular
element, which is, in general, made of thermoplastic
material.
The aforesaid continuous tubular element is then
provided, on its opposite longitudinal sides, with
appropriate areas turned inwards, in the branch
t~ referred to herein as "bellows formation.", which
enable it to be amply developed in an open condition
and enable a bottom having a certain width to be
obtained, but one that is not flat.
In fact, once the contllluOUS tubular element
provided with longitudinal side bellows formations is
created, the next step in the process 1S to use an
appropriately designed transverse welding rod, which
functions intermittently, to form both the mouth
(either opened or closed) of the bag and the weld for
2~ closing so as t=o c7btai.n the bottom of the bag,
blocking both the opposite sides of the flattened
tubular element and the inner sides of the two
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bellows formation's by means of a single weld.
The use of the above bags is by now fairly
widespread and is bound to continue increasing. The
aforesaid bags are also used for containing objects
having a certain weight, even though they present a
bottom of limited dimensions as compared to the
transverse development. that the bag may have given by
the sum of the sides of the flattened tubular element
and the size of the internal sides of the bellows all
splayed out together.
There is ~~onsequently felt t:he need to make bags
with wider bottoms, for example, bags with flat
bottoms, which will present a certain degree of
sturdiness and a certain degree of strength.
1~ So far, no solution has been found to t=he above
rather important techruical. problem.
The purpose o" they present invention is
therefore to identifv~ a solution to the technical
problem referred to above by making a bag with a wide
flat bottom.
Another purpose o:E the invention is to provide a
bag with a flat bottom that is particularly valid and
that is ablE: to perform the function outlined
previously, which will be particularly simple to
2~ construct.
Yet a further purpose ~>f the present invention
is to provide a bag with a flat bottom which will be
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able to be manutactl~.red automatically, without any
need for manual intervention for its completion.
The above purposes according to the present
invention are achieved by providing a bag with a flat
s bottom and by a mettnod for fabrication thereof, as
set forth it tine attached independent claims.
Further salient characteristics and details of
the presents invention form the .subject of the
dependent claims.
The characteristics and advantages of a bag with
a flat bottom and of a method for fabrication thereof
according to the present invention will emerge more
clearly from ttie ensuing description, which is
provided purely by way of non-limiting example, of an
1~ embodiment thereof, with reference to the attached
figures, in which:
- Figure 1 is a side view of a bag in a
folded condition or position made according to the
present invention;
- Figure 2 is a top plan view of a bottom
element in a non-operative condition, laid out flat,
which must then be included in the bag of Figure 1
according to the present invention;
- Figure 3 i.s a perspective side view of the
2i bottom element <.~f F'i.gure :'_ in a folded condition
ready for being inserted within the initial tubular
element hav_iny an ex~=ernal Shape that is the same as
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the one illustrated in Figure l;
- Figure 4 is a perspective view, from
beneath, of the bag of Figure l, when it is partially
splayed out in an operative condition and is provided
with the flat-bottom E:element: illustrated in Figures 2
and 3 ; and
- Figure ~i illustrates an enlarged view of a
closed bottom end portion of the bag of Figure 1.
With reference to tha_ various figures taken as a
whole, there i:3 illustrated in an altogether
schematic way a bag with a flat bottom according to
the invention, designated, as a whole, by 11 and
obtained according 'o the method, which itself
constitutes a novelty and inventive idea of the
invention.
The bag with flat bottom 11 is obtained from a
flattened tubular element 1~ provided with lateral
bellows formations l~~ folded towards the inside of
the tubular element itself.
The bag 11, which is illustrated finished,
envisages an open mouth 1~ and a quadrilateral bottom
15, having in the case illustrated by way of example
in Figure 4 a rectangular shape, even though the said
quadrilateral bottom ~5 may also be square.
2~ In the folded condition, the bag 11 comprises a
bottom element 16, wr~ic~ is inserted inside an open
end of the flattef~ed tubular element 12 with the free
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edges of both elements, towards the outside, set
aligned and one on top of the other.
The bottom element 16 is made initially of a
quadrilateral sheet (see Figure 2), which is folded
in a first direction into two halves along a first
folding axis 17, keeping two external sides or
parallel edges 18 parallel. too said first folding ax_Ls
17 and so that they have a size that is equal to the
initial size.
Next, in a second operating step carried out on
the aforesaid bottom element 16, the further two
sides 19 are folded in order to identify two opposite
bellows 20 by bringing a central folding line 21 of
said bellows 20 thus identified into a position
1~ perpendicular to said first axis 17.
Once the bottom element. 16 has been folded as
described above, said bottom element 16 is inserted
into the aforesaid flattened tubular element 12 by
bringing the two opposite bellows 20 of said bottom
element 16 astride of the lateral bellows 13 of the
flattened tubular element 12.
In this way, the configuration and arrangement
illustrated in Figure 1 is ach.ieVed, except for the
weld. In fact, it is at this point that the step of
2~ welding the ends facing the outside of the flattened
tubular element 12, opposite to the open mouth 14,
with the correspondin~~ ends c>f the lateral bellows 20
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of the bottom element4 16 i~> carried out.
During the above operation, the outer sides 18
of the bottom element 16 parallel to the first
folding axis 17 are Kept so that the said sides 18
are set aligned with the end of the flattened tubular
element 12. The weld is a perimetral weld, which
constrains, in a first portion 22, the sides that
remain in view of the flattened tubular element 12
with the sides 18 of the bottom element 16 and, in a
second portion 23, the sides of the internal bellows
13 of the flattened t~.zbular element 12 with the sides
or internal edges ~~f the two opposite internal
bellows 20 of the bottom element 16; of course, this
is drone whilst the latter are set in the folded
condition on top of each other.
A perimetral weld is then made between the sides
and the end bellows of the flattened tubular element
12 and the sides and the bellows of the bottom
element 16, so obt.3ining a bag, which, in the
splayed-out and open condition has a quadrilateral
flat bottom.
It is evident that a splayed-out and open bag
provided with a quadrilateral flat bottom may be
obtained also fol'.~owinq steps other than the ones
described previously, and hence the present invention
also regards, in a much simpler manner, the said bag,
irrespective of the mf_~thcad with which it is obtained.
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~t has thus been seen how the said bag with flat
bottom and the method indicated according to the
present inventiorn achieve the purposes specified
previously.
The method of fabri.cat_ion of a bag with flat
bottom, as well as the bag thus obtained according to
the present invention, as conceived herein, may
undergo numerous modifications and variations all
falling within the scope of the same invention.
Furthermore, in practice, the materials used, as
well as the dimensions and components, may be any
whatsoever according to the technical requirements.
