U.S. patent application number 09/897085 was filed with the patent office on 2001-11-08 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 | 20010038721 09/897085 |
Document ID | / |
Family ID | 26233278 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010038721 |
Kind Code |
A1 |
Bois, Henri Georges |
November 8, 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 stepsof 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: |
SCHWARTZ & WEINRIEB
Crystal Plaza One, Suite 1109
2001 Jefferson Davis Highway
Arlington
VA
22202
US
|
Assignee: |
FLEXICO-FRANCE
|
Family ID: |
26233278 |
Appl. No.: |
09/897085 |
Filed: |
July 3, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09897085 |
Jul 3, 2001 |
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09155422 |
Sep 29, 1998 |
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6261000 |
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Current U.S.
Class: |
383/64 ; 383/120;
383/61.2 |
Current CPC
Class: |
B31B 70/266 20170801;
B65D 31/10 20130101; B31B 70/8131 20170801; B31B 70/36
20170801 |
Class at
Publication: |
383/64 ; 383/120;
383/61 |
International
Class: |
B65D 033/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 29, 1998 |
FR |
PCT/FR98/00138 |
Sep 29, 1997 |
FR |
97 00936 |
Claims
1. A method of manufacturing packaging bags comprising the steps
of: providing a packaging bag sheet, having a longitudinal extent,
for forming a packaging bag; folding said packaging bag sheet so as
to form a pair of laterally spaced bellow regions within side edge
portions of said packaging bag sheet; forming cutouts within each
one of said pair of laterally spaced, bellow regions of said
packaging bag sheet so that said bag has only two sheet thicknesses
superposed with respect to each other within a mouth region of said
bellows; placing complementary male/femelle closure strips provided
with a control cursor upon said packaging bag sheet within the
vicinity of said mouth region of said bag and transversely with
respect to said longitudinal feeding direction; and heat-sealing
edges portions of said sheet to edge portions of said cutouts so as
to close and seal said bag.
2. A method according to claim 1, wherein said cursor has two
lateral flanges interconnected by means of a web and which
co-operate with an elongate central tongue placed between the
closure strips to define two converging passages for the closure
strips.
3. A method according to claim 1, wherein the closure strips are
provided on respective main support walls which are adapted to be
fixed on the packaging bag sheet and which are connected together
by an auxiliary wall adapted to be broken when the bag is opened
the first time.
4. A method according to claim 1, further comprising the steps of:
feeding said packaging bag sheet in a direction parallel to said
longitudinal extent of said packaging bag sheet; and forming said
pair of laterally spaced bellow regions by making two Z-folds which
extend parallel to said longitudinal feeding direction of the said
packaging bag sheet.
5. A method according to claim 4, wherein: each one of said Z-folds
is formed by a pair of blades that are partially superposed with
respect to each other so as to partially overlap each other and
thereby form a baffle within which a side edge portion of said
packaging bag sheet is engaged.
6. A method according to claim 4, wherein: said cutouts are formed
within said pair of laterally spaced bellow regions after said
folds have been formed within said packaging bag sheet so as to
form said pair of laterally spaced bellow regions.
7. A method according to claim 4, wherein: said cutouts are formed
within said pair of laterally spaced bellow regions before said
folds are formed within said packaging bag sheet so as to form said
pair of laterally spaced bellow regions.
8. A method according to claim 5, wherein: said cutouts are formed
within said pair of laterally spaced bellow regions by using one of
said pair of fold-forming blades as an anvil for a cutting-out
punch thereby leaving one of the faces of said packaging bag sheet
intact.
9. A method according to claim 1, further comprising the step of:
initially holding said complementary closure strips in position
upon said packaging bag sheet by spot heat-sealing ends of said
closure strips to said packaging bag sheet.
10. A method according to claim 4, further comprising the step of:
fixing said Z-folds by spot heat-sealing said Z-folds at zones
where transverse lines of heat-sealing are to be formed so as to
close said bag.
11. A method according to claim 10, wherein said formation of said
transverse lines of heat-sealing comprises the step of: forming two
mutually parallel transverse lines of heat-sealing such that one of
said transverse lines of heat-sealing forms the bottom of a bag
while the other one of said transverse lines of heat-sealing forms
the mouth of a bag.
12. A method according to claim 11, further comprising the step of:
forming a rectilinear cut line between said two transverse lines of
heat-sealing so as to separate said formed packaging bag into two
separate adjacent bags.
13. A machine for manufacturing packaging bags from packaging bag
sheets, comprising: means for feeding a packaging bag sheet having
a longitudinal extent; means for folding said packaging bag sheet
so as to form a pair of laterally spaced bellow regions within side
edge portions of said packaging bag sheet; means for forming
cutouts within each one of said pair of laterally spaced bellow
regions of said packaging bag sheet such that said packaging bag
has only two superposed sheet thicknesses within a mouth region of
said bellows; means for placing complementary male/femelle closure
strips provided with a control cursor upon said packaging bag sheet
within the vicinity of said mouth region of said bag such that said
closure strips extend transversely with respect to said
longitudinal extent of said packaging bag sheet;and means for
heat-sealing together edges portions of said packaging bag sheet to
edge portions of said cutouts so as to close and seal said bag.
14. A machine according to claim 13 wherein said cursor has two
lateral flanges interconnected by means of a web and which
co-operate with an elongate central tongue placed between the
closure strips to define two converging passages for the closure
strips.
15. A machine according to claim 13 wherein the closure strips are
provided on respective main support walls which are adapted to be
fixed on the packaging bag sheet and which are connected together
by an auxiliary wall adapted to be broken when the bag is opened
the first time.
16. A machine according to claim 13, further comprising: means for
forming said pair of laterally spaced bellow regions so as to
comprise a pair of Z-folds which extend parallel to said
longitudinal extent of said packaging bag sheet.
17. A machine according to claim 16, wherein: said means for
forming said pair of laterally spaced bellow regions comprises two
partially superposed blades that overlap each other and thereby
form a baffle into which said packaging bag sheet is engaged so as
to form said pair of Z-folds.
18. A machine according to claim 17, further comprising: a cut-out
punch; and one of said fold-forming blades comprises an anvil for
said cut-out punch when said cut-out punch is used to make said
cutouts so as to leave one of the faces of said packaging bag sheet
intact.
19. A machine according to claim 13, wherein: said machine
comprises a form, fill, and seal machine.
20. A machine according to claim 19, wherein said form, fill, and
seal machine comprises: a forming throat having an inlet that
receives said packaging bag sheet in a planar state, and an outlet
that delivers said packaging bag sheet shaped into a tube, a
filling chute which opens out into said forming throat and
consequently into said tube so as to deposit material into said
tube, longitudinal heat-sealing means for closing and sealing said
tube longitudinally, and means for sequentially generating
transverse lines of heat-sealing so as to close and seal said
formed bag.
21. A machine according to claim 13, further comprising: means for
initially securing said closure strips in position upon said
packaging bag sheet by spot heat-sealing ends of said closure
strips to said packaging bag sheet.
22. A machine according to claim 16, further comprising: means for
fixing said Z-folds by spot heat-sealing said Z-folds at zones that
are subsequently to include transverse lines of heat-sealing so as
to close and seal said bag.
23. A machine according to claim 22 further comprising:
heat-sealing means for forming two mutually parallel transverse
lines of heat-sealing such that one of said transverse line of
heat-sealing forms the bottom of a bag while the other one of said
transverse lines of heat-sealing forms the mouth of a bag.
24. A machine according to claim 23, further comprising: means for
forming a rectilinear cut line between said two transverse lines of
heat-sealing so as to separate said formed packaging bag into two
separate adjacent bags.
25. A packaging bag comprising: a folded packaging sheet, having a
longitudinal extent, for forming a packaging bag; a pair of
laterally spaced bellows formed within side edge portions of said
folded packaging bag sheet; cutout portions respectively formed
within each one of said pair of laterally spaced bellows so that
said packaging bag has only two sheet thickness superimposed with
respect to each other within a mouth region of said bag;
complementary male/female closure strips provided with a control
cursor upon said packaging bag sheet within the vicinity of said
mouth region of said bag such that said closure strips extend
transversely with respect to said longitudinal exent of said
packaging sheet; and heat-sealed regions for closing and sealing
said packaging bag.
26. A bag according to claim 25, wherein: said heat-sealed regions
of said packaging bag comprises a line of heat-sealing defined
between edge portions of said packaging bag sheet and edge portions
of said cutouts.
27. A packaging bag as set forth in claim 25, wherein said
packaging bag sheet comprises: a planar main face; first
longitudinal flaps disposed upon and integrally connected to
opposite sides of said planar main face; second longitudinal flaps
disposed upon and integrally connected to opposite sides of said
first longitudinal flaps, and auxiliary segments disposed upon and
integrally connected to said second longitudinal flaps.
28. A packaging bag as set forth in claim 25, wherein: each cutout
portion is defined by two rectilinear longitudinal edges coinciding
respectively with outer definition lines of said laterally spaced
bellows, a rectilinear transverse edge extending transversely to
said longitudinal extent of said packaging bag sheet, and a second
transverse edge that is not rectilinear and is concave towards said
mouth region of said bag.
29. A packaging bag as set forth in claim 25, wherein: each cutout
portion is defined by two rectilinear longitudinal edges which are
respectively set back from the outer definition lines of said
laterally spaced bellows, a rectilinear transverse edge extending
transversely to said longitudinal extent of said packaging bag
sheet, and a second transverse edge that is not rectilinear and is
concave towards said mouth region of said bag.
30. A packaging bag as set forth in claim 28, wherein: said second
transverse edge comprises a dihedral made up of two rectilinear
segments.
31. A packaging bag comprising: a folded packaging sheet, having a
longitudinal extent, for forming a packaging bag; a pair of
laterally spaced bellows formed within side edge portions of said
folded packaging bag sheet; cutout portions respectively formed
within each one of said pair of laterally spaced bellows so that
said packaging bag has only two sheet thickness superimposed with
respect to each other within a mouth region of said bag;
complementary male/female closure strips provided with a control
cursor upon said packaging bag sheet within the vicinity of said
mouth region of said bag such that said closure strips extend
transversely with respect to said longitudinal exent of said
packaging sheet; and heat-sealed regions for closing and sealing
said packaging bag, each one of said cutout portions being defined
by two rectilinear longitudinal edges coinciding respectively with
outer definition lines of said laterally spaced bellows, a
rectilinear transverse edge extending transversely to said
longitudinal extent of said packaging bag sheet, and a second
transverse edge that is not rectilinear and is concave towards said
mouth region of said bag.
32. A packaging bag comprising: a folded packaging sheet, having a
longitudinal extent, for forming a packaging bag; a pair of
laterally spaced bellows formed within side edge portions of said
folded packaging bag sheet; cutout portions respectively formed
within each one of said pair of laterally spaced bellows so that
said packaging bag has only two sheet thickness superimposed with
respect to each other within a mouth region of said bag;
complementary male/female closure strips provided with a control
cursor upon said packaging bag sheet within the vicinity of said
mouth region of said bag such that said closure strips extend
transversely with respect to said longitudinal event of said
packaging sheet; and heat-sealed regions for closing and sealing
said packaging bag, each one of said cutout portions being defined
by two rectilinear longitudinal edges which are respectively set
back from the outer definition lines of said laterally spaced
bellows, a rectilinear transverse edge extending transversely with
respect to said longitudinal extent of said packaging bag sheet,
and a second transverse edge that is not rectilinear and is concave
towards said mouth region of said bag.
33. A bag according to claim 32, wherein: said heat-sealed regions
of said packaging bag comprises a line of heat-sealing defined
between edge portions of said packaging bag sheet and edge portions
of said cutout portions.
34. A packaging bag as set forth in claim 32, wherein said
packaging bag sheet comprises: a planar main face; first
longitudinal flaps disposed upon and integrally connected to
opposite sides of said planar main face; second longitudinal flaps
disposed upon and integrally connected to opposite sides of said
first longitudinal flaps, and auxiliary segments disposed upon and
integrally connected to said second longitudinal flaps.
35. A packaging bag as set forth in claim 32, wherein: said second
transverse edge comprises a dihedral made up of two rectilinear
segments.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of bags for
packaging.
BACKGROUND OF THE INVENTION
[0002] Numerous packaging bags and numerous systems for
manufacturing them have already been proposed.
[0003] For bags of small thickness, 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, for example complementary
male/female strips, at the mouth of a bag.
[0004] 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.
[0005] In particular, such bags often require lateral bellows which
are difficult to make.
[0006] 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.degree. 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 make it
possible to manufacture 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 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.
[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.
OBJECT OF THE INVENTION
[0009] The present invention now seeks to improve known means for
manufacturing packaging bags having lateral bellows.
SUMMARY OF THE INVENTION
[0010] The foregoing object is achieved in the context of the
present invention by a method of manufacturing packaging bags
comprising the steps of:
[0011] providing a packaging bag sheet, having a longitudinal
extent, for forming a packaging bag;
[0012] folding said packaging bag sheet so as to form a pair of
laterally spaced bellow regions within side edge portions of said
packaging bag sheet;
[0013] forming cutouts within each one of said pair of laterally
spaced, bellow regions of said packaging bag sheet so that saidbag
has only two sheet thicknesses superposed with respect to each
other within a mouth region of said bellows
[0014] placing complementary male/femelle closure strips provided
with a control cursor upon said packaging bag sheet within the
vicinity of said mouth region of said bag and transversely with
respect to said longitudinal feeding direction and
[0015] heat-sealing edges portions of said sheet edge portions of
said cutouts so as to close and seal said bag.
[0016] In the context of the present invention, the complementary
male/female closure strips are preferably provided on respective
main support walls which are adapted to be fixed on the packaging
bag sheet and which are connected together by an auxiliary wall
adapted to be broken when the bag is opened the first time.
[0017] The present invention also provides apparatus for
implementing the method, and bags obtained thereby.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other characteristics, objects, and advantages of the
invention will become apparent upon reading the following detailed
description and upon looking at the accompanying drawings, given by
way of non-limiting example and in which like reference characters
designate like or corresponding parts throughout the several views
and wherein:
[0019] FIG. 1, described above, is a diagram showing a conventional
technique of manufacturing packaging bags having lateral
bellows;
[0020] FIG. 2 is a top plan view which shows a first step of a
method of the present invention consisting in forming two Z-folds
in a film;
[0021] FIG. 3 is a cross-section view through the film of FIG.
1;
[0022] FIG. 4 is a view similar to FIG. 2 and shows the portion of
film that is removed to form cutouts;
[0023] FIG. 5 shows the film of FIG. 4 as provided with cutouts,
when spread out flat;
[0024] FIG. 5a is a similar flat view of a variant film of the
present invention that is provided with cutouts;
[0025] FIGS. 6 to 9 show four successive steps of the method of the
present invention for forming bags;
[0026] FIG. 10 is a schematic view in perspective of a cursor of
the present invention,
[0027] FIG. 11 is a longitudinal cross-section view of the cursor
through the section plan referenced XI-XI on FIG. 10,
[0028] FIG. 12 is a first transverse cross-section view of the
cursor through the section plan referenced XII-XII on FIGS. 10 and
11 and
[0029] FIG. 13 is a second transverse cross-section viewof the
cursor through the section plan referenced XIII-XIII on FIGS. 10
and 11.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0030] 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.
[0031] The two Z-folds 110 and 120 can be formed by any appropriate
means.
[0032] 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.
[0033] The folds 110 and 120 are designed to form the lateral
bellows of the bag once it has been completed.
[0034] After the folds 110 and 120 have been made, the film as
shown in FIG. 2 has a planar 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 122 and 124 form the fold 120. The flaps
112 and 122 are connected to the main face 130 by means of 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 by means of 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.
[0035] 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 by means of lines 115 and 125.
[0036] 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.
[0037] The areas of material removed to form these cutouts 150 and
160 are shaded in FIG. 4.
[0038] The cutouts 156 and 160 are shown in the deployed state in
FIG. 5.
[0039] Finally, the cutouts 150 and 160 are shown in their real
configuration within the folds 110 and 120 in FIG. 6.
[0040] 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.
[0041] 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.
[0042] The shapes of the cutouts 150 and 160 can vary in numerous
ways.
[0043] 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. 5a, 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. 5a.
[0044] 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.
[0045] 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.
[0046] The transverse edges 156 and 166 that are closer to the
mouth of the bag are preferably rectilinear, extending transversely
relative to the longitudinal direction D of the film 100.
[0047] 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.
[0048] 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.o slashed..
[0049] The generally planar 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 5a is preferably fed directly to a conventional
form, fill, and seal machine for making bags.
[0050] Such machines are often referred to as "FFS" machines, from
the initials of the terms "form, fill, and seal".
[0051] Numerous machines of this type have already been
proposed.
[0052] 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 the formed 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 material is
inserted into the tube by means of the filling chute, and then a
second transverse line of heat-sealing once the material has been
inserted into the tube, so as to close the bag around
thematerial.
[0053] 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.
[0054] As mentioned above, according to an essential characteristic
of the present invention, the male/female closure strips 170 are
provided with a control cursor 1710.
[0055] As illustrated on FIGS. 10, 12 and 13, preferably the
male/female closure strips comprise a male/profile 172 provided on
a first main wall 174 and a female profile 176 provided on a second
main wall 178.
[0056] In a variant the male profile 172 and the female profile 176
may be replaced by equivalent complementary hooked means.
[0057] The two main walls 174 and 178 are adapted to be fixed on
the packaging bag sheet 100.
[0058] According to a preferential embodiment of the invention, as
illustrated on FIG. 10, the two main walls 174, 178 are initially
connected by an auxiliary wall 179. This auxiliary wall 179 is
adapted to be broken when the bag is opened the first time. Thus
the auxiliary wall 179 is an evidence of an opening of the bag when
it is broken.
[0059] Generally the cursor 1710 has two lateral flanges 1712, 1714
interconnected by means of a web 1716 and which co-operate with an
elongate central tongue 1718 placed between the closure strips 172,
176 to define two converging passages 1720, 1722 for the
interfittable complementary closure strips 172, 176. The central
tongue 1718 extends only on a part of the cursor 1710. Thus, when
the direction of displacement of the cursor 1710 relative to the
closure strips 172, 176 tends to force the closure strips 172, 176
into engagement, the bag is closed. In contrast, when the cursor
1710 is displaced in the opposite direction, the bag is opened by
means of the central tongue 1718 separating the closure strips 172,
176.
[0060] 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
[0061] Still more precisely, closure strips 170 are placed against
the main face 130 facing the cutouts 150 and 160, that is between
the transverse edges 156 and 158 at one end and 166 and 168 at the
other end.
[0062] The closure strips 170 are preferably of a length that is
equal to the width of the main face 130, that is the distance
between the fold lines 111 and 121.
[0063] 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 by means of 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.
[0064] 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.
[0065] 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.
[0066] Naturally, it is also necessary to synchronize carefully the
instant at which the spot heat-sealing means are operated relative
to the travel of the film 100, since the instants at which the spot
heat-sealing means operate determine both the locations of the
corresponding heat-sealing zones and the pitch of the zones.
[0067] By fixing the closure strips 170 by means of 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 to subsequently perform the heat-sealing as shown in FIG. 9,
particularly because of the resulting crushing of the ends of the
strips 170.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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. Nos. 4,655,862, 4,666,536, 4,701,361,
4,709,398, 4,878,987, 4,844,759, 4,929,225, 4,909,017, and U.S.
Pat. No. 5,111,643.
[0072] 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.
[0073] 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.
[0074] On leaving the forming throat, the film 100 is shaped into a
tubular state, as shown in FIG. 8. The laterally outer free edges
141 and 143 of the segments 140 and 142 are then brought together
and heat-sealed in a conventional manner by the above-mentioned
longitudinal heat-sealing means of the FFS machine.
[0075] The tubular film is then filled with its content by means of
the filling chute provided for this purpose.
[0076] The tubular film is then brought to face the heat-sealing
means provided for making the lines of heat-sealing shown in FIG.
9.
[0077] The following are then preferably provided at these
heat-sealing means:
[0078] two mutually parallel lines of heat-sealing 180 and 182;
and
[0079] respective lines of heat-sealing 184 and 186 at the
peripheries of the cutouts 150 and 160.
[0080] One of the transverse lines of heal-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, that is, the two main faces and the
lateral bellows, and between the bellows it connects together two
thicknesses of film corresponding to the main faces.
[0081] 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.
[0082] Once the lines of heat-sealing 180 and 182 have been made, a
transverse rectilinear cut line 181 can be formed between them so
as to separate two adjacent bags.
[0083] 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.
[0084] 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.
[0085] 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.
[0086] Naturally, the present invention is not limited to the
embodiment described above, but extends to any variant coming
within the spirit thereof.
[0087] 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.
[0088] 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.
[0089] 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. 5a makes it possible to improve the lateral sealing
of the bags.
[0090] Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claim, the present invention may be practiced otherwise than as
specifically described herein.
* * * * *