U.S. patent application number 09/871909 was filed with the patent office on 2001-09-27 for method and apparatus for manufacturing packaging bags, and bags obtained thereby.
This patent application is currently assigned to FLEXICO - FRANCE. Invention is credited to Bois Henri, Georges.
Application Number | 20010023571 09/871909 |
Document ID | / |
Family ID | 9503075 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010023571 |
Kind Code |
A1 |
Bois Henri, Georges |
September 27, 2001 |
Method and apparatus for manufacturing packaging bags, and bags
obtained thereby
Abstract
The present invention relates to a method of manufacturing
packaging bags having lateral bellows, the method being
characterized by the fact that it comprises the steps consisting
in: forming respective cutouts (150, 160) in each of the two
lateral, bellows-forming zones of a packaging bag sheet (100) so
that the bag has only two thicknesses superposed at the mouth of
said bellows, at least over a portion of its width; and
heat-sealing (184, 186) the adjacent edges of the sheet to the
peripheries of the cutouts (150, 160) to close the bag. The
invention also provides apparatus for implementing the method and
bags obtained thereby.
Inventors: |
Bois Henri, Georges;
(Neuilly-sur-Seine, FR) |
Correspondence
Address: |
Steven W. Weinrieb
SCHWARTZ & WEINRIEB
Crystal Plaza One, Suite 1109
2001 Jefferson Davis Highway
Arlington
VA
22202
US
|
Assignee: |
FLEXICO - FRANCE
|
Family ID: |
9503075 |
Appl. No.: |
09/871909 |
Filed: |
June 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09871909 |
Jun 4, 2001 |
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09155422 |
Sep 29, 1998 |
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6261000 |
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09155422 |
Sep 29, 1998 |
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PCT/FR98/00138 |
Jan 29, 1998 |
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Current U.S.
Class: |
53/410 ;
53/451 |
Current CPC
Class: |
B31B 70/8131 20170801;
B31B 70/266 20170801; B31B 70/36 20170801; B65D 31/10 20130101 |
Class at
Publication: |
53/410 ;
53/451 |
International
Class: |
B65B 009/20; B65B
061/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 1997 |
FR |
97 00936 |
Claims
1. A method of manufacturing packaging bags having lateral bellows,
the method being characterized by the fact that it comprises the
steps consisting in: forming respective cutouts (150, 160) in each
of the two lateral, bellows-forming zones of a packaging bag sheet
(100) so that the bag has only two thicknesses superposed at the
mouth of said bellows, at least over a portion of its width; and
heat-sealing (184, 186) the adjacent edges of the sheet to the
peripheries of the cutouts (150, 160) to close the bag.
2. A method according to claim 1, characterized by the fact that it
includes the step consisting in making two Z-folds (110, 120)
parallel to the longitudinal direction (D) of the film (100).
3. A method according to claim 2, characterized by the fact that
each of the Z-folds (110, 120) is formed by means of two blades
(200, 202, 200, 204) that are partially superposed to overlap so as
to form a baffle in which the film (100) is engaged.
4. A method according to claim 2 or 3, characterized by the fact
that the cutouts (150, 160) are formed after the folds (110, 120)
have been formed.
5. A method according to claim 2 or 3, characterized by the fact
that the cutouts (150, 160) are formed before the folds (110, 120)
are formed.
6. A method according to claim 3, characterized by the fact that
the cutouts (150 and 160) are formed using one of the fold-forming
blades (200) as an anvil for a cutting-out punch, thereby leaving
one of the faces (130) of the film untouched.
7. A method according to any one of claims 2 to 6, characterized by
the fact that after the folds (110, 120) have been made, the film
has a plane main face (130) extended on either side at its
longitudinal edges by first longitudinal flaps (112, 122), which
are themselves extended by second longitudinal flaps (114, 124),
which are in turn extended outwards by auxiliary segments (140,
142).
8. A method according to any one of claims 1 to 7, characterized by
the fact that each cutout (150, 160) is defined by two rectilinear
longitudinal edges (152 & 154, 162 & 164) coinciding
respectively with the outer generator lines of the lateral bellows,
a rectilinear transverse edge (156, 166) extending transversely to
the longitudinal direction (D) of the film (100), and a second
transverse edge (158, 168) that is not rectilinear, being concave
towards the mouth of the bag.
9. A method according to any one of claims 1 to 7, characterized by
the fact that each cutout (150, 160) is defined by two rectilinear
longitudinal edges (152 & 154, 162 & 164) situated
respectively set back from the outer generator lines of the lateral
bellows, a rectilinear transverse edge (156, 166) extending
transversely to the longitudinal direction (D) of the film (100),
and a second transverse edge (158, 168) that is not rectilinear,
being concave towards the mouth of a bag.
10. A method according to claim 8 or 9, characterized by the fact
that the second transverse edge (158, 168) is constituted by a
dihedral made up of two rectilinear segments (158a & 158b, and
168a & 168b).
11. A method according to any one of claims 1 to 10, characterized
by the fact that the film (100) provided with two Z-folds (110,
120) and fitted with two cutouts (150, 160) is shaped using a form,
fill, and seal machine.
12. A method according to claim 11, characterized by the fact that
the form, fill, and seal machine has a forming throat whose input
receives the film (100) in the flat state and whose output delivers
the film shaped into a tube, a filling chute which opens out into
the forming throat and consequently into said tube, longitudinal
heat-sealing means for closing the tube longitudinally, and means
suitable for sequentially generating transverse lines of
heat-sealing to close a bag.
13. A method according to any one of claims 1 to 12, characterized
by the fact that it further comprises the step consisting in
placing complementary male/female closure strips (170) on the film
(100) in the mouth zone of a bag, transversely to the longitudinal
direction (D), facing the cutouts (150 and 160).
14. A method according to claim 13, characterized by the fact that
the strips (170) are initially held in position on the film (100)
by spot heat-sealing at their ends.
15. A method according to claim 2, characterized by the fact that
the folds (110, 120) are fixed by spot heat-sealing at the zones
where the transverse lines of heat-sealing are to be formed.
16. A method according to any one of claims 1 to 15, characterized
by the fact that it comprises the steps consisting in making: two
mutually parallel transverse lines of heat-sealing (180, 182), one
coinciding with a transverse edge (156, 166) of each cutout to form
the bottom of a bag, the other being made between the transverse
edges (156 & 158, 166 & 168) of the cutouts to form the
mouth of a bag; and additional lines of heat-sealing (184, 186)
each formed by two segments (184a & 184b, 186a & 186b)
respectively covering the longitudinal edges (152 & 154, 162
& 164) of the cutouts and also the transverse edges (158 and
168) of the cutouts.
17. A method according to claim 16, characterized by the fact that
a rectilinear line of cut (181) is formed between the two
transverse lines of heat-sealing (156, 166) to separate two
adjacent bags.
18. A machine for manufacturing packaging bags having lateral
bellows to implement the method according to any of claims 1 to 17,
the machine being characterized by the fact that it comprises:
means suitable for forming respective cutouts (150, 160) in each of
the two zones forming lateral bellows of a sheet (100) for a
packaging bag, such that the bag has only two superposed
thicknesses at the mouths of said bellows, at least over a fraction
of its width; and means (184, 186) suitable for heat-sealing
together the adjacent edges of the sheet at the peripheries of the
cutouts (150, 160) to close the bag.
19. A machine according to claim 18, characterized by the fact that
it includes means for forming two Z-folds (110, 120) parallel to
the longitudinal direction (D) of the film (100).
20. A machine according to claim 19, characterized by the fact that
it includes two partially superposed blades (200, 202, 200, 204)
that overlap to form a baffle into which the film (100) is engaged
to form the folds (110, 120).
21. A machine according to claim 20, characterized by the fact that
one of the fold-forming blades (200) forms an anvil for a
cutting-out punch when making the cutouts (150, 160), thereby
leaving one of the faces (130) of the film intact.
22. A machine according to any one of claims 18 to 21,
characterized by the fact that each cutout (150, 160) is defined by
two rectilinear longitudinal edges (152 & 154, 162 & 164)
respectively coinciding with the outer generator lines of the
lateral bellows, a rectilinear transverse edge (156, 166) extending
transversely to the longitudinal direction (D) of the film (100),
and a second transverse edge (158, 168) that is not rectilinear,
being concave towards the mouth of the bag.
23. A machine according to any one of claims 18 to 21,
characterized by the fact that each cutout (150, 160) is defined by
two rectilinear longitudinal edges (152 & 154, 162 & 164)
situated so as to be set back respectively from the outer generator
lines of the lateral bellows, a rectilinear transverse edge (156,
166) extending transversely to the longitudinal direction (D) of
the film (100), and a second transverse edge (158, 168) that is not
rectilinear, being concave towards the mouth of the bag.
24. A machine according to claim 22 or 23, characterized by the
fact that the second transverse edge (158, 168) constitutes a
dihedral made up of two rectilinear segments (158a & 158b, 168a
& 168b).
25. A machine according to any one of claims 18 to 24,
characterized by the fact that it constitutes a form, fill, and
seal machine.
26. A machine according to any one of claims 18 to 25,
characterized by the fact that it includes a forming throat having
an inlet that receives the film (100) in the plane state, and an
outlet that delivers the film shaped into a tube, a filling chute
which opens out into the forming throat and consequently into said
tube, longitudinal heat-sealing means for closing the tube
longitudinally, and means suitable for sequentially generating
transverse lines of heat-sealing to close a bag.
27. A machine according to any one of claims 18 to 26,
characterized by the fact that it further comprises means suitable
for placing complementary male/female closure strips (170) on the
film (100) in the mouth zone of a bag, the strips extending
transversely to the longitudinal direction D and facing the cutouts
(150 and 160).
28. A machine according to claim 27, characterized by the fact that
it includes means suitable for securing the strips (170) initially
in position on the film (100) by spot heat-sealing at their
ends.
29. A machine according to any one of claims 18 to 28,
characterized by the fact that it includes means suitable for
fixing the folds (110, 120) by spot heat-sealing in the zones that
are subsequently to include the transverse lines of
heat-sealing.
30. A machine according to any one of claims 18 to 29,
characterized by the fact that it comprises heat-sealing means
suitable for making: two mutually parallel transverse lines of
heat-sealing (180, 182), one coinciding with a transverse edge
(156, 166) of each cutout to form the bottom of a bag, the other
being made between the transverse edges (156 & 158, 166 &
168) of the cutouts to form the mouth of a bag; and additional
lines of heat-sealing (184, 186) each made up of two segments (184a
& 184b, 186a & 186b) respectively covering the longitudinal
edges (152 & 154 and 162 & 164) and the transverse edges
(158 and 168) of the cutouts.
31. A machine according to claim 30, characterized by the fact that
it comprises means suitable for making a rectilinear line of cut
(181) between the two transverse lines of heat-sealing (156, 166)
to separate two adjacent bags.
32. A packaging bag having lateral bellows made by implementing the
method according to any one of claims 1 to 17.
33. A bag according to claim 32, characterized by the fact that it
includes respective cutouts (150, 160) in each of the two zones
forming lateral bellows and a line of heat-sealing (184, 186) on
the periphery of the cutouts (150, 160) to close the bag.
Description
[0001] The present invention relates to the field of bags for
packaging.
[0002] Numerous packaging bags and numerous systems for
manufacturing them have already been proposed.
[0003] For bags of small thickness, i.e. that are generally flat in
the filled state, known means generally give satisfaction. Under
such circumstances, the bags are generally formed using two plane
sheets that are bonded together along three sides and that are
provided with closure means, e.g. complementary male/female strips,
at the mouth of a bag.
[0004] In contrast, until now, making 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.
[0005] In particular, such bags often require lateral bellows which
are difficult to make.
[0006] Accompanying FIG. 1 shows, diagrammatically, a known
technique for making 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.degree. to the travel direction S of said sheets. Said 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 make 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.degree. 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.
[0007] Document FR-A-2 686 063 describes another technique of
manufacturing packaging bags with bellows that consist 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 said flaps, in reforming the
bag, and in bonding the closure strips to said flaps that have been
put into place. Unfortunately, because of its complexity, that
technique does not give full satisfaction.
[0008] 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.
[0009] The present invention now seeks to improve known means for
manufacturing packaging bags having lateral bellows.
[0010] This 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 consisting in:
[0011] 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 said bellows, at
least over a portion of its width; and
[0012] heat-sealing the adjacent edges of the sheet to the
peripheries of the cutouts to close the bag.
[0013] The present invention also provides apparatus for
implementing the method, and bags obtained thereby.
[0014] Other characteristics, objects, and advantages of the
invention will appear on reading the following detailed description
and on looking at the accompanying drawings, given by way of
non-limiting example and in which:
[0015] FIG. 1, described above, is a diagram showing a conventional
technique of manufacturing packaging bags having lateral
bellows;
[0016] FIG. 2 shows a first step of a method of the present
invention consisting in forming two Z-folds in a film;
[0017] FIG. 3 is a cross-section view through the same film;
[0018] FIG. 4 is a view similar to FIG. 2 and shows the portion of
film that is removed to form cutouts;
[0019] FIG. 5 shows the same film as provided with cutouts, when
spread out flat;
[0020] FIG. 5bis is a similar flat view of a variant film of the
present invention that is provided with cutouts; and
[0021] FIGS. 6 to 9 show four successive steps of the method of the
present invention for forming bags.
[0022] In FIG. 2, there can be seen a film 100 provided with two
Z-folds 110 and 120 that are parallel to the longitudinal direction
D of the film 100.
[0023] The two Z-folds 110 and 120 can be formed by any appropriate
means.
[0024] Each of them is preferably formed by means of two blades 200
& 202 or 200 & 204 that are superposed with partial
overlap, as shown in FIG. 3, so as to form a baffle into which the
film 100 is engaged.
[0025] The folds 110 and 120 are designed to form the lateral
bellows of the bag once it has been completed.
[0026] After the folds 110 and 120 have been made, the film as
shown in FIG. 2 has a plane main face 130 that is to form a main
face of the bag after it has been completed. On its longitudinal
edges, this main face 130 is extended on either side by first
longitudinal flaps 112 and 122 which are themselves extended by
second longitudinal flaps 114 and 124. The flaps 112 and 114 form
the fold 110. The flaps 112 and 114 form the fold 120. The flaps
112 and 122 are connected to the main face 130 via fold lines 111
and 121. The flaps 112 and 122 are folded towards the middle of the
face 130 from the fold lines 111 and 121 so that they underlie the
main face 130. The flaps 114 and 124 are connected to the flaps 112
and 122 via fold lines 113 and 123. The flaps 114 and 124 extend
outwards from the fold lines 113 and 123. The flaps 114 and 124 are
also of the same length as the flaps 112 and 122 so as to underlie
them respectively, being immediately beneath them. Finally, each of
the flaps 114 and 124 is extended outwards by auxiliary segments
140 and 142. These auxiliary segments 140 and 142 are designed, in
combination, to form the second main face of the bags. As shown in
FIG. 2, the two segments 140 and 142 are preferably of identical
width. Nevertheless, this condition is not essential. What is
essential is that the segments 140 and 142 possess a total width
that is slightly greater than the width of the face 130 so as to
form the second face of the bags after they have been folded about
their outer longitudinal free edges, as explained below with
reference to FIG. 8.
[0027] After the step of forming the folds 110 and 120 as shown in
FIG. 2, the flaps 114 and 124 are substantially coplanar with the
segments 140 and 142. The flaps 114 and 124 are connected to the
segments 140 and 142 via lines 115 and 125.
[0028] As mentioned above, according to an essential characteristic
of the present invention, the method of forming a bag includes a
step of cutting out pairs of cutouts 150 and 160 at regular
intervals in each of the zones that is to form a lateral
bellows.
[0029] The areas of material removed to form these cutouts 150 and
160 are shaded in FIG. 4.
[0030] The cutouts 150 and 160 are shown in the deployed state in
FIG. 5.
[0031] Finally, the cutouts 150 and 160 are shown in their real
configuration within the folds 110 and 120 in FIG. 6.
[0032] The cutouts 150 and 160 can be formed in the film 100 before
making the folds 110 and 120. Under such circumstances, their
initial shape is as shown in FIG. 5.
[0033] Nevertheless, it is preferable for the cutouts 150 and 160
to be formed after the folds 110 and 120 have been made. The
cutouts 150 and 160 can be made in the film 100 by any appropriate
means. The cutouts 150 and 160 are preferably made using the blade
200 as an anvil that co-operates with a cutting-out punch so as to
leave the face 130 of the film intact.
[0034] The shapes of the cutouts 150 and 160 can vary in numerous
ways.
[0035] The cutouts 150 and 160 preferably extend between the lines
111 and 115 on one side and the lines 121 and 125 on the other
side, as shown in FIG. 5. Nevertheless, in a variant, as shown in
FIG. 5bis, the cutouts 150 and 160 can be formed so as to be set
back from the above-mentioned lines 111 & 115 and 121 &
125, as shown in FIG. 5bis.
[0036] More precisely, and as shown in the accompanying figures,
each of the cutouts 150 and 160 is defined by two longitudinal
edges 152 & 154 and 162 & 164, and by two transverse edges
156 & 158 and 166 & 168.
[0037] The longitudinal edges 152 & 154 and 162 & 164 are
rectilinear and coincide respectively with the lines 111, 115, 121,
and 125 in FIG. 5, which lines themselves constitute the final
outer generator lines of the lateral bellows. In the folded state
as shown in FIG. 6, the pairs of edges 152 & 154 or 162 &
164 are superposed.
[0038] The transverse edges 156 and 166 that are closer to the
mouth of a bag are preferably rectilinear, extending transversely
relative to the longitudinal direction D of the film 100.
[0039] The second transverse edges 158 and 168 that are closer to
the bottom of a bag are preferably not rectilinear, being concave
towards the mouth of the bag. More precisely, the second transverse
edges 158 and 168 are preferably in the form of a dihedral made up
of two rectilinear segments 158a & 158b or 168a & 168b. The
above-mentioned pairs of segments 158a & 158b and 168a &
168b constituting respective second transverse edges 158 and 168
are preferably identical in length. They extend respectively over
the flaps 112 & 114 and 122 & 124. In this way, the
segments 158a & 158b and 168a & 168b intersect on the
middle fold lines 113 and 123.
[0040] As a non-limiting example, the segments 158a & 158b and
168a & 168b are inclined by about 15.degree. relative to a line
extending transversely to the longitudinal direction D, such that
the dihedral angle formed between the pairs of segments 158a &
158b and 168a & 168b is about 150.degree..
[0041] The generally plane film 100 together with its two Z-folds
110 and 120 and provided with its two cutouts 150 and 160 as shown
in FIGS. 5 and 5bis is preferably fed directly to a conventional
form, fill, and seal machine for making bags.
[0042] Such machines are often referred to as "FFS" machines, from
the initials of the term "form, fill, and seal".
[0043] Numerous machines of this type have already been
proposed.
[0044] Most such machines have: a forming throat which has an input
receiving the film in the flat state and which has an output
delivering the film shaped into a tube; a filling chute which opens
out into the forming throat and consequently into said tube;
longitudinal heat-sealing means for closing the tube
longitudinally; and means suitable for acting sequentially to
generate a first transverse line of heat-sealing before substance
is inserted into the tube via the filling chute, and then a second
transverse line of heat-sealing once the substance has been
inserted into the tube, so as to close the bag around the
substance.
[0045] The general structure of such machines is well known to the
person skilled in the art, so the structure is not described in
detail below.
[0046] It will be observed that in the context of the present
invention, it is preferable for complementary male/female closure
strips 170 to be deposited on the film 100 in the vicinity of the
mouth zone of a bag transversely to the longitudinal direction D,
and prior to the film 100 being brought to the forming throat of
the FFS machine, as shown in FIG. 7.
[0047] Still more precisely, closure strips 170 are placed against
the main face 130 facing the cutouts 150 and 160, i.e. between the
transverse edges 156 and 158 at one end and 166 and 168 at the
other.
[0048] The closure strips 170 are preferably of a length that is
equal to the width of the main face 130, i.e. the distance between
the fold lines 111 and 121.
[0049] After being placed on the film 100, the strips 170 are
secured in position on the film 100 by any appropriate means.
Preferably, after they have been put into place, the strips 170 are
initially fixed to the film 100 solely via their ends using a spot
heat-sealing technique. The strips 170 are subsequently fixed to
the main faces of the bag over the full length of their inside
faces, preferably when making the transverse lines of heat-sealing
in the manner described below with reference to FIG. 9. When the
strips 170 are secured by spot heat-sealing at their ends, the
lateral edges of the bag facing the folds 110, 120 can also be
secured by spot heat-sealing at the zones where the transverse
lines of heat-sealing shown in FIG. 9 will subsequently be made for
holding the above-mentioned folds together and preventing them from
deforming as the film 100 moves on.
[0050] Nevertheless, in a variant, at least one of the strips 170
may be heat-sealed to the film 100 along its entire length as soon
as it is put into place.
[0051] The above-mentioned means for spot heat-sealing are
preferably adjustable along the length of the film 100 so as to
make it possible for them to be adjusted accurately relative to the
desired length for the bags and to the zones that will subsequently
correspond to the transverse lines of heat-sealing.
[0052] Naturally, it is also necessary to synchronize carefully the
instant at which said spot heat-sealing means are operated relative
to the travel of the film 100, since the instants at which said
spot heat-sealing means operate determine both the locations of the
corresponding heat-sealing zones and the pitch of said zones.
[0053] By fixing the closure strips 170 via their ends, and
possibly also by fixing the folds 110 and 120 by spot heat-sealing,
subsequent travel of the film 100 is made easier and it is also
easier subsequently to perform the heat-sealing as shown in FIG. 9,
particularly because of the resulting crushing of the ends of the
strips 170.
[0054] The means for making the above-mentioned spots of
heat-sealing can be generally like the means described in document
FR-A-2 638 419.
[0055] In a variant, the closure strips 170 are fixed, and the
folds 110 and 120 are held temporarily by spots that are not made
by heat-sealing, but are made by any equivalent means, such as by
static discharge or by spots of adhesive.
[0056] The means designed for depositing the closure strips 170 on
the film 100 so that they extend transversely to the longitudinal
direction D of the film 100 can be implemented in numerous
ways.
[0057] By way of non-limiting examples, these means may be like the
means described in the following documents: U.S. Pat. No.
4,617,683, U.S. Pat. No. 4,655,862, U.S. Pat. No. 4,666,536, U.S.
Pat. No. 4,701,361, U.S. Pat. No. 4,709,398, U.S. Pat. No.
4,878,987, U.S. Pat. No. 4,844,759, U.S. Pat. No. 4,929,225, U.S.
Pat. No. 4,909,017, and U.S. Pat. No. 5,111,643.
[0058] Once the folds 110 and 120 have been made and the closure
strips 170 have been put into place and secured, at least
temporarily, the film assembly 100 as shown in FIG. 7 is sent to
the forming throat of an FFS machine, as mentioned above.
[0059] Where appropriate, special means may be provided at the
forming throat to facilitate passage thereover, in particular of
the folds 110, 120. By way of example, complementary windows may be
provided on the forming throat to receive the folds 110 and
120.
[0060] On leaving the forming throat, the film 100 is shaped into a
tubular state, as shown in FIG. 8. The outer free edges 141 and 143
of the segments 140 and 142 are then brought together and
heat-sealed in conventional manner by the above-mentioned
longitudinal heat-sealing means of the FFS machine.
[0061] The tubular film is then filled with its content via the
filling chute provided for this purpose.
[0062] The tubular film is then brought to face the heat-sealing
means provided for making the lines of heat-sealing shown in FIG.
9.
[0063] The following are then preferably provided at these
heat-sealing means:
[0064] two mutually parallel lines of heat-sealing 180 and 182;
and
[0065] respective lines of heat-sealing 184 and 186 at the
peripheries of the cutouts 150 and 160.
[0066] One of the transverse lines of heat-sealing 180 coincides
with the transverse edges 156 and 166 of the cutouts. This
transverse line of heat-sealing 180 is designed to form the bottom
of a bag. In the lateral bellows, it serves to connect together
four thicknesses of film (the two main faces and the lateral
bellows) and between the bellows it connects together two
thicknesses of film (corresponding to the main faces).
[0067] The other transverse line of heat-sealing 182 is made
between the transverse edges 156 & 158 and 166 & 168 of the
cutouts. This transverse line of heat-sealing 182 is designed to
form the mouth of a bag. It interconnects the two main faces.
[0068] Once the lines of heat-sealing 180 and 182 have been made, a
transverse rectilinear line of cut 181 can be formed between them
to separate two adjacent bags.
[0069] The lines of heat-sealing 184 and 186 are respectively made
up of pairs of segments 184a & 184b and 186a & 186b
respectively covering the longitudinal edges 152 & 154 and 162
& 164 and also the transverse edges 158 and 168 of the
cutouts.
[0070] In this way, the lines of heat-sealing 184, 182, and 186
intersect, thereby ensuring that the mouth of a bag is properly
sealed. More precisely, the segments 184a and 186a connect together
the outside edges of the two main faces of the bag, while the
segments 184b and 186b connect together the edges 158a & 158b
and the edges 168a & 168b.
[0071] The method of the present invention has the fundamental
advantage of limiting the lines of heat-sealing 184, 182, and 186
to two thicknesses of film, in particular where the closure strips
170 are fixed thereto, whereas most conventional methods need to
perform heat-sealing through four thicknesses of film at the
lateral bellows.
[0072] Naturally, the present invention is not limited to the
embodiment described above, but extends to any variant coming
within the spirit thereof.
[0073] For example, it is possible to make bags using a film of the
type shown in FIG. 7 having cutouts 150, 160 and closure strips
170, without applying the film to a form, fill, and seal machine as
mentioned above. The film can then be shaped to have a tubular
state by any appropriate conventional means.
[0074] In the context of the present invention, the film 100 can be
varied in numerous ways. It is preferably constituted by a
thermoplastic film. Nevertheless, the invention applies to any
flexible film that can be used for making a packaging bag.
[0075] Furthermore, the person skilled in the art will understand
that although, in the example shown in FIG. 5, the longitudinal
edges 152, 154, 162, and 164 of the cutouts 150 and 160 coincide
with the fold lines 111, 115, 121, and 125, so that the lines of
heat-sealing 184a and 186a are made on two thicknesses of film,
when the longitudinal edges 152, 154, 162, 164 of the cutouts 150
and 160 are set back from the fold lines 111, 115, 121, and 125,
then the lines of heat-sealing 184a and 186a are made, at least in
part, on four superposed thicknesses of film. The same applies for
end portions of the transverse lines of heat-sealing 180 and 182.
The lines of heat-sealing 184a and 186a may also be made at least
in part so as to be set back from the fold lines 111, 115, 121, and
125, as shown in FIG. 9. The variant embodiment of the cutouts as
shown in FIG. 5bis makes it possible to improve the lateral sealing
of the bags.
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