Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 ~5'7~5
'L'hi'; inventioll re:la~es to a web comprisiny a plurality
of plastic bags of the type having gusset folds a:LoncJ the long~
itudinal sides, at least comprisiny a central lonqitudinal gusset
fold edge and two outer longitudinal gusset fold edges which
bound a first and seconcl yusset Eold with a ~irst transverse bo-t-
tom seal which extends at least in the area between the central
longitudinal gusset fold elges.
When known p]astlcs bags of this -type have been ~illed,
they are provided with a second transverse bottom seal at -their
other side which extends over the whole width of -the bay.
Such a bag has the disadvantage tha-t it ~oes no-t have
a real block or parallelopepidal shape when heing filled, so that
stacking may give rise to difficul-ties.
In the e~isting market there is a great demand for
plastics bags, both ends of which have a real block shape when
the bag has been filled.
Though this could be realised by providing the bags
with two normal block bottoms, this involves great expenditure
owing to longitudinal incisions, folding operations, and the like,
which are required when a bag of this type is produced.
The present invention provides a web of plastics bags
of the aforementioned type which can be comple-tely closed by
means of one single second transverse bottom seal after filling
the bag, whereafter the flat]y positioned filled bag is given
a rectangular parallelopepidal shape, hereinafter referred to
has a block-shape.
Accordingly, the present invention provides a web com-
prising two layers of foil in the form of a flattened tube and
divided transversely in-to a plurality of sections, each of which
when separated from the web and opened out forms a plastic bag of
rectangular parallelepipedal shape, said web having along each of
its longitudinal edges a gusset folded inwardly so as to lie be-
1 1 5 '~ 5
t~/ecl-l sa:id two klyers, c~ac~ sai(l (~ s.set ~efinirl(J arl inner yus-
set :folcl and two outer gu6set ol.ds interconnected by respective
yusset par-ts, each section havlng a tran.sverse bo-ttom seal at
one end thereof connectlng sai.d two layers together at least in
-the region between the inner folds oE the gussets at opposite
sicles of the web, first c~usset seals at said one en~ of each sec-
tion extendi.ny obliquely towards said one end from each outer
gusset fold to the inner gusse-t fold at each side of the web, each
said first gusset seal connecting one said gusset part to the web
layer i.n contact therewith, sa:id first gusse-t seals or e~tensions
thereof intersectiny the transverse bottom seal substantially in
the region near the intersection of the -transverse bottom edge
with the inner gusset folds, said transverse bottom seal beiny
arranged to close the bag bottom either alone or in co-operation
with the first gusset seals, and second gusset seals at said
other end of each section extending obliquely inwardly and to-
wards said other end from each outer gusset fold to the inner
gusset fold at each side of the web, each said second gusset
seal connecting one said gusset part to the web layer in contact
therewith, and further gusset seals extending from the free inner
ends of the second gusset seals or near thereto towards\the--out-e-
web and connecting the gusset parts to the respective web layers
in contact therewith, and a transverse incision formed in one of
the web layers at said other end of each section to allow each
on
section to be filled and formed into a bag while ~ the web.
A web o:E this type has the great advantage that the
bag to be filled does not have to be handled separately but can
be filled when it is still connected with the web. Furthermore,
each bag can be easily filled by forming a filling opening of a
very determined clrcumference, that is to say a filling opening
which is defined by the two innermost end sections of the second
gusset fold part seals, whilst a subsequent filling of the bag
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carl be easlly ~er~orllled by provicl:inq a secorl(l transverse bottom
seal, wherea~te~r the combination oE second tran.sver~e bottom seal
and the aforementior,ed second gusset fold par-t seals provides a
second block bot-tom when the bag i.s filled.
Preferably, the t~bular foil is ~irst provided with at
least one first and at least one seconcl gusset fold part seal
on either sicle of the foil, and aft:er having moved the foil over
a distance greater than the yreatest distance between the second
and first gusset fold part seals, a transverse seal is applied.
This measure is very important Eor the continuous pro-
duction of a web oE bags. For forming the first and second gusset
fold part seals, a separation means must be held between the first
and second gusset folds.
If now a transverse bottom seal connecting all four
layers in the gusset folds is Eormed before the zone where the
gusset fold part seals are formed, the separation means have to
be removed from between the gusset fold in order to let pass the
transverse bottom seal, and immediately thereafter the separation
means must be reintroduced between the gusset folds. This remo~val
and reintroduction of the separation means is not necessary if the
transverse bottom seal is formed after the formation of the gusset
fold part seals. In that case the separation means can be held
in a fixed position.
So as to obtain an optimum block bottom shape, the first
and second fold part seals extend under an angle of 45.
In order to simplify the filling operation of the bags
when introducing the filling nozzles, third gusset fold part seals
are provided which adjoin the second gusset fold part seals, where-
by the second and the first gusset fold part seals form a triangle
together with the longitudinal gusset fold edges.
The third gusset fold seals create a funnel shaped open-
ing of the bag which facilitates the filling operation.
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l~reEer:a))ly, ~o~l~th gusset Eold part seals extend per-
pendiclllar to the longitucl:irlal gusset fold edcJes. Two fourth
gusset fold part seals .situated on the same side are pre~erably
united to form one seal.
Such a fourth seal oFfers the great advantage that the
sides of the bag are consiclerably streng-thenecl and that four foil
layers do no-t have to be connected lo each other in the slcle
region of the bag. In the central par-t of ~he bag only two foil
layers need be conn~cted during -tlle sealing opera-tion.
By providing one of the foil layers of -the tubular foil
of the web with anlincision or opening in -the region be-tween the
second gusset fold part seals and the nearest firs-t transverse
bot-tom sea], -the bags can be easily filled while maintaining the
connection of the bag with the web. The bag is separated from the
web after the filling operation.
When the tubular foil is still flat the other foil side
of the tubular foil may then be provided with a per~oration so
as to facilitate removal o~ the bag from the web.
A perforation running over the entire cirucmference of
the tubular foil may also be provided in the region between the
first bottom seal and the nearest second gusset fold part seals.
This embodiment lends itself well for removing a bag from a web.
The invention in another aspect relates to a method for
filli~g a plastics bag having gusset folds along the longitudinal
sides, at least comprising a central and two outer longitudinal
gusset fold edges which bound a first and a second gusset fold
part with a first transverse bottom seal which extends at least
between the central longitudinal gusset fold edges. The plastics
bag is filled and subsequently a second transverse bottom seal is
provided in such a manner that the second gusset fold part seals
or their extensions intersect the second transverse bottom seal
principally in a region near the intersection of the second trans-
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verse bottc)m 5et.~1 Wi.th !:lle ccntraL longituclin~l gusse~ fold edges,
whereas the second transverse~ bottom s~al closes -the bay eith~r
in or no-t in co-operation wi-th the second g~sse-t fold seal ~arts.
PreEerably, the first and second -transverse bo-ttom
seals extend from -the oLl-ter lonyitudinal gusset fold edyes and
uniting the superimposed foil layers in the side reyions of the
bags to form one single seal.
The invention will now be described in more deta.il
by way of example only with referellce to -the accompanying draw-
ings, in which;
~ig. 1 shows a web comprising various interconnected
plastics bags;
Fig. 2 shows a part of a web of plastics bags;
E'ig. 3 shows parts of a web of plastics bags, illustr-
ating various gusset fold part seals;
Fig. 4 shows a closed plastic bag of figure 3;
Fig. 5 shows a ready-made filled bag;
Fig. 6 shows the members for forming first and second
gusset fold seals;
Fig. 6a shows a tubular foil with first and second
gusset fold seals obtained in this way;
Fig. 7 shows the step of forming the first transverse
seals; and
Fig. 7a shows the web with transverse and gusset fold
seals.
Fig. 1 shows a web of a plurality of plastics bags 1,
each bag having gusset folds along the longitudinal sides, com-
prising two outer longitudinal gusset fold edges 2 and 3 respect~
ively 2a and 3a, and central longitudinal gusset fold edge is
4, 4a respectively.
The ends of the plastics bags 1 have a first transverse
bottom heat-seal 12 so that the superlmposed foil layers la and
3 1~7B2t;
Ib are at leclst :intercollnected in the re~iorl bet~leen the central
longitudinal ~uss~t fold edcles 4, 4a.
q'he first tr~nsverse bottom seal :L2 preferably extends
onto the outer lonyitudinal gusset fold edges 2, 3, 2a, 3a To
form -the seal 12, the superimposed oil layers la and lb are
interconnectecl, whereas the foil ]ay~rs la and lb, and firs-t yusset
folds parts 5, 5a and second folds par-ts 6, 6a, are all inter-
connected in the edge regions. A s~al oE this t~pe produ-es a
very strong bag and excellen-t appearance in the filled condition.
To obtain a block-bottom shape in the filled bag a
first fold part seal 8 extends from the intersectlon 8a, 8a' oE
the transverse bot-tom seal 12 with the central longitudinal gusset
fold edge 4 to the outer longitudinal gusset ~old edge 2. "Seal"
means here a heat-seal. ~lhen the bag is still flat another first
gusset fold part seal 9 is formed underneath said seal 8, which
extends in the same direction as said gusset fold part seal 8.
On the other side of the bag similar first gusset fold
part seals 10, 11 extend between the intersection 8a' of the
transverse bottom seal 12 with central longitudinal gusset fold
edge 4a and a point on one of the outer longitudinal gusset fold
edges 2a, 3a. The first gusset fold part seals 8, 9, 10, 11
extend expediently under an angle of 45 with respect to the outer
longitudinal gusset fold edges.
The other end of the bag comprises second gusset fold
parts 13, 14, 15 and 16, which extend from the outer longitudinal
gusset fold edges 2 and 3 onto the central longitudinal gusset
fold edges 2a, 3a respectively, onto the central longitudinal
gusset fild edge 4a. The second gusset fold seals 13, 14, 15,
16 extend at an angle of 45 with respect to the extension of the
line which connects the end sections 17 and 18 of the aformention-
ed four second fold part seals.
As shown in Figure 4 a second transverse bottom seal 19
I I S ~
ca~ be ~)rovicle(l al~el rilllncJ thc~ i)ag ~rllls seal extends between
the a~orementioned sections 17 allcl 1~.
In order to obtain a bag which is ag strong as possible,
the seal 19 ex-tends alollg the edge regions where there are the
first and seco~ usset fold seals 8, 9; 10, 11; and 13, 14; 15,
16, respectively. rrhe superimposed layers in the edge regions
are connected to form combined third gusset ~o:Ld part seals 21-
and 20 as will be exp]ained later.
In order to simplify the finaL welding operation, the
thircl seals 20, 21 can be provided in -the web. In some cases
difficulties may arise when a seal 19, which is contained at both
ends by the seals 20 and 21 in the edge regions, has-to be provided
at a filling location since the latter seal consists of four
foil layers which are interconnected, whereas the seal 19 has
only to connect two foil layers la, lb with one another.
In order to obtain a very good Eilling opening, two
separate third gusset fold pa~t seals 20a, 20b, 21a and 21b, which
-are interconnected in the filled bag is closed, may be provided
instead of combined third seals 20, 21 as shown in Fig 3.
The embodiment of Fig. 3 shows a bag which also com-
prises fourth gusset fold part seals 25, 26, 27, 28 provided in
the same manner as the Eirst fold seals 8, 9, 10, 11, respectively,
and which extend moreover approximately in the same direction as
the aforementioned first fold seals 8, 9, 10, 11. The fourth
gusset fold part seals 25, 26, 27, 28 offer the advantage that on
easy centering of the bag below the filling machine can be realiz-
ed. The gusset seals may have another sharper angle than 45 with
respect to the outer longitudinal gusset fold edge 2. This is
true also for the fourth gusset seals.
Fig. 2 shows a web with bags wherein instead of two
facing third gusset fold seals 20a, 20b and 21a, 21b only single
seals 20, 21 which each interconnect four layers, by heat seal-
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incl are useclO The sea:ls ~0, 21 extend pre~erably beyond the
central longitudinal gusset ~old edyes 4, 4a, sinc~ in that case
a very good seal can be obtained by heat~sealing. These seals
then adjoin the end sections 17a, 18a.
Fig. 5 shows a ready-made bag which is ob-tained by
using a plastic bag of a web according to Fig. 1. setween -two
subsequent bags one of the foil layers la may be provided with
an incision 23 so as to enable filling said bag (see Fig. 1).
Underneath the incision 23 in the other foil layer lb, a perEor-
ation 24 can he made so as to facilitate tearing the bag off the
web after the filling operation. The incision 23 can also extend
on either side into incisions 23a and 23b, which cut the gusset
through folds so as to facilitate filling the bags. The webs
can also have a perforation 24 along their entire circumference.
When a web is provided with such a perforation 24, the bag can be
easily torn off the web.
It will be self-evident that the perforations are always
in the vicinity of the first transverse bottom seal 12 of each
bag. The first gusset fold part seals 8, 9, 10, 11 may not
e.~tend to the central edges 4 and 4a. It goes without saying
that they can also terminate before reaching the outer longitudinal
g~lsset fold edges, but this is not preferable.
F'ig. 6 shows the first phase of forming first or second
gusset fold seals 8, 9, 10, 11 or 13, 14, 15, 16. In order to
prevent heat sealing of, e.g., gusset fold 5a to gusset fold 6a,
f~ f~ c ~,~
a separating means 30, e.g., a Pertinax/~tplate, is positioned
between fold parts 5a and 6a. The heat sealing members 29a, 29b
form the seals as required. These seals can be formed in about
1.5 seconds. Fig. 6a shows the web af-ter forming the gusset fold
seals 8, 9, 13, 14, 15, 16, 28, etc.
Fig. 7 shows the step of forming -the first transverse
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secl.ls 1.2, ior closirl~J tl~c tub~lL.-Ir oi.].. '~ .is closure i.s ob-tained
by means of a transversc heat sea]. bar 31. and support 32.
Ilowever, support 32 may be a heat: seal bar. The transverse scal
can be obtainecl in about 2 to 4 seconds.
It should be notecl-th.lt -the assembly 31, 32 will
only be active aEter forming at least one palr oE first and second
gusset fold par-t seals such as 8, 9 and 13, 14, 10, 11 and 15,
16 and the web part has rnoved from position lb -to position la,
over a distance of at least the dist.ance A, which is the cJreatest
distance between first and second gusset fold seals at one side
of the foil. In this way the separa-ting means 30 may be hek1
continuously in the gusset fold between parts 5, 6 and 5a, 6a
as the transverse heat seal bar is only active a~ter formation
of the gusset fold part seals.
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