U.S. patent application number 10/340422 was filed with the patent office on 2004-07-15 for method for dual manufacture of reclosable bags on hfvf machine.
Invention is credited to Ausnit, Steven.
Application Number | 20040134166 10/340422 |
Document ID | / |
Family ID | 32711328 |
Filed Date | 2004-07-15 |
United States Patent
Application |
20040134166 |
Kind Code |
A1 |
Ausnit, Steven |
July 15, 2004 |
Method for dual manufacture of reclosable bags on HFVF machine
Abstract
A method for dual manufacture of reclosable packages on a
horizontal-form, vertical fill machine. The method comprising the
following steps: extending a web of bag making film under tension
in a machine direction; joining one zipper tape to the web along a
first zone of joinder generally aligned with the machine direction;
joining another zipper tape to the web along a second zone of
joinder generally parallel to the first zone of joinder and spaced
apart therefrom; and folding the web in first, second and third
mutually parallel zones extending in the machine direction. The
first zone of folding is disposed between a first edge of the web
and the one zipper tape, the second zone of folding is disposed
between the two zipper tapes, and the third zone of folding is
disposed between the other zipper tape and a second edge of the
web. The resulting folded web with attached zippers has a generally
W-shaped profile. The two halves of the W-shaped web are
cross-sealed, filled, and then top-sealed to form respective chains
of filled receptacles. The completed packages are then severed from
the respective chains of receptacles.
Inventors: |
Ausnit, Steven; (New York,
NY) |
Correspondence
Address: |
OSTRAGER CHONG & FLAHERTY LLP
825 THIRD AVE
30TH FLOOR
NEW YORK
NY
10022-7519
US
|
Family ID: |
32711328 |
Appl. No.: |
10/340422 |
Filed: |
January 10, 2003 |
Current U.S.
Class: |
53/412 |
Current CPC
Class: |
B65B 61/188 20130101;
B65B 9/093 20130101; Y10S 493/927 20130101 |
Class at
Publication: |
053/412 |
International
Class: |
B65B 061/18 |
Claims
1. An article of manufacture comprising: a web of bag making film
folded under tension along first, second and third folds, said
folded web reversing its direction along said folds to form a
serpentine cross-sectional profile with first through fourth walls,
said second wall being disposed between said first and third walls,
said third wall being disposed between said second and fourth
walls, a bottom of said first wall being connected to a bottom of
said second wall along said first fold, a top of said second wall
being connected to a top of said third wall along said second fold,
and a bottom of said third wall being connected to a bottom of said
fourth wall along said third fold; a first zipper tape having a
portion disposed between said first and second walls of said web,
and joined to at least one of said first and second walls; and a
second zipper tape having a portion disposed between said third and
fourth walls of said web, and joined to at least one of said third
and fourth walls, wherein each of said first and second zipper
tapes comprises first and second mutually interlockable portions in
an interlocked state.
2. The article as recited in claim 1, wherein each of said first
and second zipper tapes further comprises a respective web
integrally formed with said respective first and second mutually
interlockable portions.
3. The article as recited in claim 1, wherein each of said first
and second zipper tapes further comprises first and second flanges
having respective ends connected to said first and second mutually
interlockable portions.
4. The article as recited in claim 1, further comprising a first
multiplicity of sliders mounted to said first zipper tape and a
second multiplicity of sliders mounted to said second zipper
tape.
5. The article as recited in claim 1, wherein each of said zipper
tapes is in the form of a string zipper.
6. The article as recited in claim 1, wherein said first and second
zipper tapes are disposed closer to said second fold than to said
first or third fold.
7. The article as recited in claim 1, wherein said first and second
zipper tapes are disposed closer to said first or third fold than
to said second fold.
8. The article as recited in claim 1, wherein said article is
moving in a direction generally parallel to said second fold and a
leading portion of said second fold is cut.
9. The article as recited in claim 1, wherein said first and second
walls are cross sealed at regular spaced intervals to separate the
space between said first and second walls into a first series of
receptacles, and said third and fourth walls are cross sealed at
said regular spaced intervals to separate the space between said
third and fourth walls into a second series of receptacles.
10. The article as recited in claim 9, wherein at least one of said
first series of receptacles and at least one of said second series
of receptacles are filled with product.
11. A method of manufacturing an article, comprising the following
steps: extending a web of bag making film under tension in a
machine direction; joining a first zipper tape to said web along a
first zone of joinder generally aligned with said machine
direction; joining a second zipper tape to said web along a second
zone of joinder generally parallel to said first zone of joinder of
said first zipper tape and spaced apart therefrom; and folding said
web in first, second and third mutually parallel zones extending in
said machine direction, said first zone of folding being disposed
between a first edge of said web and said first zipper tape, said
second zone of folding being disposed between said first and second
zipper tapes, and said third zone of folding being disposed between
said second zipper tape and a second edge of said web.
12. The method as recited in claim 11, wherein said first and third
zones of folding are folded in a first direction and said second
zone of folding is folded in a second direction opposite to said
first direction.
13. The method as recited in claim 11, wherein said first and third
zones of folding are folded before said second zone of folding is
folded.
14. The method as recited in claim 11, further comprising the
following steps: joining said first zipper tape to said web along a
third zone of joinder generally parallel to said first zone of
joinder; and joining said second zipper tape to said web along a
fourth zone of joinder generally parallel to said second zone of
joinder.
15. The method as recited in claim 11, wherein said folded web
reverses its direction along said folds to form a serpentine
cross-sectional profile with first through fourth walls, said
second wall being disposed between said first and third walls, said
third wall being disposed between said second and fourth walls, a
bottom of said first wall being connected to a bottom of said
second wall along said first fold, a top of said second wall being
connected to a top of said third wall along said second fold, and a
bottom of said third wall being connected to a bottom of said
fourth wall along said third fold,
16. The method as recited in claim 11, further comprising the
following steps: intermittently advancing said web in said machine
direction; and cutting a leading portion of said second zone of
folding during said advancing step.
17. The method as recited in claim 15, further comprising the steps
of cross sealing said first and second walls at regular spaced
intervals to separate the space between said first and second walls
into a first series of receptacles, and cross sealing said third
and fourth walls at said regular spaced intervals to separate the
space between said third and fourth walls into a second series of
receptacles.
18. The method as recited in claim 17, further comprising the steps
of filling respective receptacles of said first and second series
with product and then sealing and severing said filled
receptacles.
19. The method as recited in claim 18, wherein said filling step
comprises filling product through open sections of said first and
second zipper tapes.
20. The method as recited in claim 11, further comprising the steps
of inserting a first multiplicity of sliders on said first zipper
tape and inserting a second multiplicity of sliders on said second
zipper tape.
21. An article of manufacture comprising: a web of bag making film
folded under tension along first, second and third folds, said
folded web reversing its direction along said folds to form a
serpentine cross-sectional profile with first through fourth walls,
said second wall being disposed between said first and third walls,
said third wall being disposed between said second and fourth
walls, a bottom of said first wall being connected to a bottom of
said second wall along said first fold, a top of said second wall
being connected to a top of said third wall along said second fold,
and a bottom of said third wall being connected to a bottom of said
fourth wall along said third fold; and a zipper strip comprising a
base having a first portion joined to said second wall and a second
portion joined to said third wall, wherein said base is folded and
wrapped around said second fold of said web, said zipper strip
further comprising first and second profiled closure members
supported by said base and generally parallel to each other, said
first profiled closure member being disposed between said first and
second walls of said web, and said second profiled closure member
being disposed between said third and fourth walls of said web.
22. The article as recited in claim 21, further comprising second
and third zipper strips, said second zipper strip comprising a
third profiled closure member interlocked with said first profiled
closure member, and said third zipper strip comprising a fourth
profiled closure member interlocked with said second profiled
closure member.
23. The article as recited in claim 21, further comprising second
and third zipper strips respectively joined to said first and
fourth walls of said web, said second zipper strip comprising a
third profiled closure member that is interlockable with said first
profiled closure member, and said third zipper strip comprising a
fourth profiled closure member that is interlockable with said
second profiled closure member.
24. The article as recited in claim 21, wherein said zipper strip
further comprises third and fourth profiled closure members
supported by said base, said third profiled closure member being
interlockable with said first profiled closure member, and said
fourth profiled closure member being interlockable with said second
profiled closure member.
25. The article as recited in claim 21, wherein said article is
moving in a direction generally parallel to said second fold and a
leading portion of said second fold is cut.
26. The article as recited in claim 21, wherein said first and
second walls are cross sealed at regular spaced intervals to
separate the space between said first and second walls into a first
series of receptacles, and said third and fourth walls are cross
sealed at said regular spaced intervals to separate the space
between said third and fourth walls into a second series of
receptacles.
27. The article as recited in claim 26, wherein at least one of
said first series of receptacles and at least one of said second
series of receptacles are filled with product.
28. A method of manufacturing an article, comprising the following
steps: extending a web of bag making film under tension in a
machine direction; joining a first zipper strip to said web along a
first zone of joinder generally aligned with said machine
direction, said first zipper strip comprising a base joined to said
web, and first and second profiled closure members supported by
said base and generally parallel to each other; and folding said
web and said base of said first zipper strip along a first zone of
folding that overlaps a central portion said first zone of joinder,
said first and second profiled closure members being disposed on
opposite sides of said first zone of folding.
29. The method as recited in claim 28, further comprising the steps
of: joining a second zipper strip to said web along a second zone
of joinder generally parallel to said first zone of joinder and
spaced apart therefrom, said second zipper strip being disposed
between a first edge of said web and a first edge of said base of
said first zipper strip; and joining a third zipper strip to said
web along a third zone of joinder generally parallel to said first
zone of joinder and spaced apart therefrom, said third zipper strip
being disposed between a second edge of said web and a second edge
of said base of said first zipper strip, wherein said second zipper
strip comprises a third profiled closure member interlockable with
said first profiled closure member, and said third zipper strip
comprises a fourth profiled closure member interlockable with said
second profiled closure member.
30. The method as recited in claim 29, further comprising the steps
of folding said web along second and third zones of folding that
are generally parallel to said first zone of folding, said first
zone of folding being disposed between a first edge of said web and
a first edge of said base of said first zipper strip, and said
second zone of folding being disposed between a second edge of said
web and a second edge of said base of said first zipper strip.
31. The method as recited in claim 30, further comprising the steps
of interlocking said third profiled closure member with said first
profiled closure member, and said fourth profiled closure member
with said second profiled closure member.
32. An integrally formed hinged zippered structure comprising first
and second profiled closure members, first and second hinge lines,
a first web having one end connected to said first closure member
and another end connected to said first hinge line, a second web
having one end connected to said second closure member and another
end connected to said second hinge line, and a third web having one
end connected to said first hinge line and the other end connected
to said second hinge line.
33. The zippered structure as recited in claim 32, further
comprising a third profiled closure member interlocked with said
first profiled closure member, a fourth profiled closure member
interlocked with said second profiled closure member, a fourth web
having one end connected to said third closure member and the other
end connected to said first hinge line, and a fifth web having one
end connected to said fourth closure member and the other end
connected to said second hinge line.
34. The zippered structure as recited in claim 32, further
comprising a first slider mounted to said first and third profiled
closure members, and a second slider mounted to said second and
fourth profiled closure members.
35. An article of manufacture comprising a zippered structure as
recited in claim 32 and a web of bag making film folded under
tension along first, second and third folds, said folded web
reversing its direction along said folds to form a serpentine
cross-sectional profile with first through fourth walls, said
second wall being disposed between said first and third walls, said
third wall being disposed between said second and fourth walls, a
bottom of said first wall being connected to a bottom of said
second wall along said first fold, a top of said second wall being
connected to a top of said third wall along said second fold, and a
bottom of said third wall being connected to a bottom of said
fourth wall along said third fold, said third web having a first
portion joined to said second wall and a second portion joined to
said third wall, said third web being folded and wrapped around
said second fold of said web of bag making film.
36. The article as recited in claim 35, further comprising a first
zipper part comprising a third closure member and a first zipper
flange, and a second zipper part comprising a fourth closure member
and a second zipper flange, said third closure member being
interlocked with said first closure member, said fourth closure
member being interlocked with said second closure member, said
first zipper flange having one end connected to said third closure
member and another end joined to said first wall, and said second
zipper flange having one end connected to said fourth closure
member and another end joined to said fourth wall.
37. A zippered structure comprising a zipper web and first through
fourth profiled closure members connected to said zipper web, said
first through fourth closure members being disposed generally in
parallel with each other, said first closure member being
interlocked with said second closure member, thereby forming a
first fold said first zipper web, and said third closure member
being interlocked with said fourth closure member, thereby forming
a second fold in said zipper web, and further comprising a web of
bag making film joined to a central portion of said zipper web
extending from said second closure member to said third closure
member.
38. The zippered structure as recited in claim 37, wherein said
zipper web comprises a first line of weakness disposed along said
first fold and a second line of weakness disposed between along
said second fold.
39. The zippered structure as recited in claim 37, wherein said web
of bag making film is also joined to said zipper web in first and
second zones proximal to said first and fourth closure members
respectively.
40. A method of manufacturing an article, comprising the following
steps: extending a web of bag making film under tension in a
machine direction; folding said web in first, second and third
mutually parallel zones extending in said machine direction, said
folded web reversing its direction along said zones of folding to
form a serpentine cross-sectional profile with first through fourth
walls, said second wall being disposed between said first and third
walls, said third wall being disposed between said second and
fourth walls, a bottom of said first wall being connected to a
bottom of said second wall along said first fold, a top of said
second wall being connected to a top of said third wall along said
second fold, and a bottom of said third wall being connected to a
bottom of said fourth wall along said third fold; inserting at
least a portion of a first zipper tape between said first and
second walls of said folded web; inserting at least a portion of a
second zipper tape between said third and fourth walls of said
folded web; joining said first zipper tape to at least one of said
first and second walls; and joining said second zipper tape to at
least one of said third and fourth walls.
41. The method as recited in claim 40, further comprising the
following steps: intermittently advancing said web in said machine
direction; and cutting a leading portion of said second zone of
folding during said advancing step.
42. The method as recited in claim 40, further comprising the steps
of cross sealing said first and second walls at regular spaced
intervals to separate the space between said first and second walls
into a first series of receptacles, and cross sealing said third
and fourth walls at said regular spaced intervals to separate the
space between said third and fourth walls into a second series of
receptacles.
43. The method as recited in claim 42, further comprising the steps
of filling respective receptacles of said first and second series
with product and then sealing and severing said filled
receptacles.
44. The method as recited in claim 40, further comprising the steps
of inserting a first multiplicity of sliders on said first zipper
tape and inserting a second multiplicity of sliders on said second
zipper tape.
45. A machine for forming, filling and sealing a folded web of bag
making film, said folded web having a serpentine cross-sectional
profile comprising first and second folded portions in respective
upright positions and open at the tops, and a central inverted
folded portion extending in a machine direction, said central
inverted folded portion connecting said first folded portion to
said second folded portion, wherein said machine comprises: an
upright saddle having a generally constant profile in said machine
direction, wherein said central inverted folded portion of said web
is supported by said saddle and slides along said saddle as said
web advances in said machine direction. means for cross sealing
said first and second folded portions of said web at regular spaced
intervals to form respective first and second series of open
receptacles; means for filling successive receptacles of said first
and second series concurrently; and means for sealing successive
filled receptacles of said first and second series closed.
46. The machine as recited in claim 45, further comprising means
for attaching first and second zipper tapes (with or without
sliders inserted thereon) to said web of bag making film.
47. The machine as recited in claim 46, wherein said zipper tapes
comprises zipper flanges, and said zipper tape attaching means
comprise first through fourth heat sealing bars for sealing said
zipper flanges to said web of bag making film, and first and second
separating plates for separating said zipper flanges of said
respective first and second zipper tapes during sealing to prevent
seal-through.
48. The machine as recited in claim 46, wherein said zipper tapes
are of the type that do not have zipper flanges, and said zipper
tape attaching means comprise first through fourth heat sealing
bars for sealing said zipper tapes to said web of bag making film,
and first and second separating plates for separating the zipper
profiles of said respective first and second zipper tapes during
sealing to prevent seal-through.
49. An article of manufacture comprising: a web of bag making film
folded under tension along first, second and third folds, said
folded web reversing its direction along said folds to form a
serpentine cross-sectional profile with first through fourth walls,
said second wall being disposed between said first and third walls,
said third wall being disposed between said second and fourth
walls, a bottom of said first wall being connected to a bottom of
said second wall along said first fold, a top of said second wall
being connected to a top of said third wall along said second fold,
and a bottom of said third wall being connected to a bottom of said
fourth wall along said third fold; a first zipper tape having a
portion disposed between said first and second walls of said web,
and joined to at least one of said first and second walls; and a
second zipper tape having a portion disposed between said third and
fourth walls of said web, and joined to at least one of said third
and fourth walls, wherein each of said first and second zipper
tapes comprises first and second mutually interlockable portions in
an interlocked state.
50. The article of manufacture as recited in claim 49, further
comprises a first peel seal above said first zipper tape and a
second peel seal above said second zipper tape.
51. The article of manufacture as recited in claim 49, further
comprises a first peel seal below said first zipper tape and a
second peel seal below said second zipper tape.
52. The method as recited in claim 18, wherein said filling step
comprises filling product through openings between the unsealed
sides of said first and second zipper tapes and the opposing
portions of said web of bag making film.
53. The method as recited in claim 18, wherein said filling step
comprises opening the respective receptacles of said first and
second series by moving sliders mounted to the zippers of said
receptacles and filling product through said open zippers.
Description
BACKGROUND OF THE INVENTION
[0001] This invention generally relates to reclosable packaging and
methods for manufacturing reclosable packaging. In particular, the
invention relates to the manufacture of reclosable packages on a
horizontal-form, vertical fill (HFVF) machine.
[0002] Reclosable bags are finding ever-growing acceptance as
primary packaging, particularly as packaging for foodstuffs such as
cereal, fresh vegetables, snacks and the like. Such bags provide
the consumer with the ability to readily store, in a closed, if not
sealed, package any unused portion of the packaged product even
after the package is initially opened. To gain acceptance as a
primary package for foodstuffs, it is virtually mandatory that the
package exhibit some form of tamper evidence to protect the
consumer and maintain the wholesomeness of the contained product.
In addition, in many cases it is necessary that food product be
hermetically packaged.
[0003] Reclosable fastener assemblies are useful for sealing
thermoplastic pouches or bags. Such fastener assemblies typically
include a plastic zipper and a plastic slider. Typically, the
plastic zippers include a pair of interlockable profiled members
that fasten together to form a closure. As the slider moves across
the profiles, the profiles are opened or closed. The profiles in
plastic zippers can take on various configurations, e.g.
interlocking rib and groove elements having so-called male and
female profiles, interlocking alternating hook-shaped closure
members, etc. Reclosable bags having slider-operated zippers are
generally more desirable to consumers than bags having zippers
without sliders because the slider eliminates the need for the
consumer to align the interlockable zipper profiles before causing
those profiles to engage.
[0004] Methods and apparatus for manufacturing reclosable plastic
bags on form-fill-seal (FFS) machines are well known in the art.
The use of high-speed automated equipment to form, fill and seal a
reclosable package is quite common in the industry.
[0005] One known type of FFS machine is a horizontal-form, vertical
fill (HFVF) machine that places slider-zipper tape proximal to a
fold in a web of bag making film, forms receptacles, and then fills
the receptacles through an open package bottom at the top of folded
web. This machine typically operates as follows. A pull roller of
the HFVF machine draws a continuous length of bag making film
dispensed from a supply roll in a machine direction. As the bag
making film is dispensed in the machine direction, a flattening
roller positions the film on a horizontal plane. At the same time,
a continuous length of interlocked zipper tape assembly (without
sliders) is unwound from a coil and passed through a slider
insertion device. Also a chain or series of sliders is unwound from
a coil or supplied by a vibratory hopper and fed to the slider
insertion device. The slider insertion device inserts sliders onto
the zipper tape at regular spaced intervals corresponding to the
length of a zipper in each package. The resulting slider-zipper
assembly is placed on the bag making film in alignment with the
machine direction. The continuous length of zipper tape assembly
with sliders inserted thereon is longitudinally positioned on the
bag making film in parallel with and offset from a line where the
film will be folded. At a first sealing station, one zipper half is
permanently sealed to the film by conduction heat sealing. These
permanent seals and the mutual engagement of the zipper profiles
maintain the alignment of the slider-zipper assembly with the fold
line as the film with attached slider-tape assembly is drawn around
a folder plow or board. The folder plow folds the film lengthwise
along the fold line. Optionally, as the bag making film is fed over
the folder plow, a perforator perforates the film below the
interlocking zipper profiles to form respective parallel lines of
preferential tearing, where a bag header can be torn off of the
package. At a second sealing station, the other zipper half is
permanently sealed to the bag making film. At the next station, the
opposing walls of the bag making film are cross sealed along a zone
transverse to the direction of film movement, the seal zone having
sufficient width to form respective side seals on successive
packages when the seal zone is cut down the middle by a cutter. The
cross seals form discrete receptacles that can be filled before or
after the cutting station. After filling, the opposing top edges of
the folded web (representing the bottom of the packages) are sealed
together at another sealing station, forming a bottom seal. If the
bags have been filled before the cutting station, the bag making
film is then cut along a side seal to separate the filled package
from the web of bag making film.
[0006] In accordance with variations of the foregoing machine, the
slider-zipper tape assembly can be attached proximal to the top
edge of the folded web, i.e., opposite the fold, and the package
can be filled either by moving the slider to open the zipper (when
both zipper halves are sealed to the film) or by separating the
slider-zipper tape assembly from an adjacent unsealed wall of the
bag making film, filling the receptacle through the resulting gap,
and then sealing the unsealed film wall to the slider-zipper tape
assembly. Similar methods of manufacture can be used to make
zippered bags that do not have sliders for operating the
zipper.
[0007] There is a need for a method of manufacture and an apparatus
for increasing the production capacity of such HFVF machines.
BRIEF DESCRIPTION OF THE INVENTION
[0008] The invention is directed to dual manufacture of reclosable
packaging on a horizontal form, vertical fill (HFVF) machine. The
aspects of the invention, some of which are set forth in greater
detail immediately hereinafter, include both methods and apparatus
for dual manufacture of reclosable packages, as well as the
transitory article of manufacture that is a precursor to the final
reclosable packages. The basic concept has application in the
manufacture of zippered bags with or without sliders.
[0009] One aspect of the invention is an article of manufacture
comprising: a web of bag making film folded under tension along
first, second and third folds, the folded web reversing its
direction along the folds to form a serpentine cross-sectional
profile with first through fourth walls, the second wall being
disposed between the first and third walls, the third wall being
disposed between the second and fourth walls, a bottom of the first
wall being connected to a bottom of the second wall along the first
fold, a top of the second wall being connected to a top of the
third wall along the second fold, and a bottom of the third wall
being connected to a bottom of the fourth wall along the third
fold, a first zipper tape having a portion disposed between the
first and second walls of the web, and joined to at least one of
the first and second walls; and a second zipper tape having a
portion disposed between the third and fourth walls of the web, and
joined to at least one of the third and fourth walls. Each of the
first and second zipper tapes comprises first and second mutually
interlockable portions in an interlocked state. These zippers may
be opened and closed by sliders preloaded on the zippers.
[0010] Another aspect of the invention is a method of manufacturing
an article, comprising the following steps: extending a web of bag
making film under tension in a machine direction; joining a first
zipper tape to the web along a first zone of joinder generally
aligned with the machine direction; joining a second zipper tape to
the web along a second zone of joinder generally parallel to the
first zone of joinder of the first zipper tape and spaced apart
therefrom; and folding the web in first, second and third mutually
parallel zones extending in the machine direction, the first zone
of folding being disposed between a first edge of the web and the
first zipper tape, the second zone of folding being disposed
between the first and second zipper tapes, and the third zone of
folding being disposed between the second zipper tape and a second
edge of the web. As used herein and in the claims, the term "zone
of folding" encompasses both a line of folding and a gradual fold
that spans a band-shaped zone. These zippers may be opened and
closed by sliders preloaded on the zippers.
[0011] A further aspect of the invention is an article of
manufacture comprising: a web of bag making film folded under
tension along first, second and third folds, the folded web
reversing its direction along the folds to form a serpentine
cross-sectional profile with first through fourth walls, the second
wall being disposed between the first and third walls, the third
wall being disposed between the second and fourth walls, a bottom
of the first wall being connected to a bottom of the second wall
along the first fold, a top of the second wall being connected to a
top of the third wall along the second fold, and a bottom of the
third wall being connected to a bottom of the fourth wall along the
third fold, and a zipper strip comprising a base having a first
portion joined to the second wall and a second portion joined to
the third wall, wherein the base is folded and wrapped around the
second fold of the web. The zipper strip further comprises first
and second profiled closure members supported by the base and
generally parallel to each other, the first profiled closure member
being disposed between the first and second walls of the web, and
the second profiled closure member being disposed between the third
and fourth walls of the web.
[0012] Yet another aspect of the invention is a method of
manufacturing an article, comprising the following steps: extending
a web of bag making film under tension in a machine direction;
joining a zipper strip to the web along a zone of joinder generally
aligned with the machine direction, the zipper strip comprising a
base joined to the web, and first and second profiled closure
members supported by the base and generally parallel to each other;
and folding the web and the base of the zipper strip along a zone
of folding that overlaps a central portion the zone of joinder, the
first and second profiled closure members being disposed on
opposite sides of the zone of folding.
[0013] A further aspect of the invention is an integrally formed
hinged zippered structure comprising first and second profiled
closure members, first and second hinge lines, a first web having
one end connected to the first closure member and another end
connected to the first hinge line, a second web having one end
connected to the second closure member and another end connected to
the second hinge line, and a third web having one end connected to
the first hinge line and the other end connected to the second
hinge line. These zippers may be opened and closed by sliders
preloaded on the zippers.
[0014] Another aspect of the invention is an integrally formed
zippered structure comprising a web and first through fourth
profiled closure members connected to the web, the first through
fourth closure members being disposed generally in parallel with
each other, the first closure member being interlocked with the
second closure member, and the third closure member being
interlocked with the fourth closure member. The web comprises first
and second web portions connected by a third web portion. The first
web portion comprises a first zone connected to the first closure
member and a second zone connected to the second closure member,
while the second web portion comprises a third zone connected to
the third closure member and a fourth zone connected to the fourth
closure member.
[0015] Yet another aspect of the invention is a method of
manufacturing an article, comprising the following steps: extending
a web of bag making film under tension in a machine direction;
folding the web in first, second and third mutually parallel zones
extending in the machine direction, the folded web reversing its
direction along the zones of folding to form a serpentine
cross-sectional profile with first through fourth walls, the second
wall being disposed between the first and third walls, the third
wall being disposed between the second and fourth walls, a bottom
of the first wall being connected to a bottom of the second wall
along the first fold, a top of the second wall being connected to a
top of the third wall along the second fold, and a bottom of the
third wall being connected to a bottom of the fourth wall along the
third fold; inserting at least a portion of a first zipper tape
between the first and second walls of the folded web; inserting at
least a portion of a second zipper tape between the third and
fourth walls of the folded web; joining the first zipper tape to at
least one of the first and second walls; and joining the second
zipper tape to at least one of the third and fourth walls. These
zippers may be opened and closed by sliders preloaded on the
zippers.
[0016] A further aspect of the invention is a machine for forming,
filling and sealing a folded web of bag making film, the folded web
having a serpentine cross-sectional profile comprising first and
second folded portions in respective upright positions and open at
the tops, and a central inverted folded portion extending in a
machine direction, the central inverted folded portion connecting
the first folded portion to the second folded portion. The machine
comprises: an upright saddle having a generally constant profile in
the machine direction, wherein the central inverted folded portion
of the web is supported by the saddle and slides along the saddle
as the web advances in the machine direction. means for cross
sealing the first and second folded portions of the web at regular
spaced intervals to form respective first and second series of open
receptacles; means for filling successive receptacles of the first
and second series concurrently; and means for sealing successive
filled receptacles of the first and second series closed.
[0017] Other aspects of the invention are disclosed and claimed
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a drawing showing a sectional view of a precursor
article in accordance with one embodiment of the invention. This
view (as well as the views of FIGS. 2-9, 13-15, and 17) is taken at
an intermediate stage in the dual manufacture of reclosable
packages on a HFVF machine.
[0019] FIG. 2 is a drawing showing a sectional view of the
precursor article of FIG. 1 after a further folding step.
[0020] FIG. 3 is a drawing showing a sectional view of a precursor
article in accordance with another embodiment of the invention.
[0021] FIG. 4 is a drawing showing a sectional view of the
precursor article of FIG. 3 after a further folding step.
Structural variations are depicted in dashed or dotted lines.
[0022] FIG. 5 is a drawing showing a sectional view of a precursor
article in accordance with a further embodiment of the
invention.
[0023] FIG. 6 is a drawing showing a sectional view of the
precursor article of FIG. 5 after a further folding step.
[0024] FIG. 7 is a drawing showing a sectional view of a precursor
article having a hinged zipper in accordance with a further
embodiment of the invention.
[0025] FIG. 8 is a drawing showing a hinged zipper construction in
accordance with the embodiment shown in FIG. 7.
[0026] FIG. 9 is a drawing showing the hinge of the hinged zipper
of FIG. 8 in detail.
[0027] FIG. 10 is a drawing showing a sectional view of a precursor
article in accordance with another embodiment of the invention, the
view being taken before the web of bag making film is folded.
[0028] FIG. 11 is a drawing showing a sectional view of the
precursor article of FIG. 8 after the web of bag making film has
been folded.
[0029] FIG. 12 is a drawing showing a top plan view of a stage in a
method of manufacturing yet another embodiment of the invention.
For the sake of illustration, it has been assumed that the bag
making film is optically transparent, so that structural features
disposed under the folded film are visible. The manufacturing stage
depicted in FIG. 12 precedes the step wherein the web of bag making
film is folded along a central zone.
[0030] FIGS. 13 and 14 are drawings respectively showing side
elevational and top plan views of a later stage in the method of
manufacture partially depicted in FIG. 12. The manufacturing stage
depicted in FIGS. 13 and 14 is subsequent in time to the step
wherein the web of bag making film is folded along a central
zone.
[0031] FIGS. 15-18 are drawings showing respective sectional views
of the machine depicted in FIG. 13, the sections being taken along
the lines designated 15-15, 16-16, 17-17, and 18-18 respectively in
FIG. 13.
[0032] FIG. 19 is a drawing showing a side elevational view of a
variation of the method of manufacture depicted in FIG. 13.
[0033] FIG. 20 is a drawing showing a sectional view of a precursor
article provided with peel seals in accordance with yet another
embodiment of the invention.
[0034] FIG. 21 is a drawing showing a method for attaching flanged
zipper assemblies inside the folds of a doubly folded web of bag
making film.
[0035] FIG. 22 is a drawing showing a method for attaching string
zipper assemblies inside the folds of a doubly folded web of bag
making film.
[0036] FIG. 23 is a drawing showing a top view of the zipper
sealing arrangement being used in FIG. 22.
[0037] Reference will now be made to the drawings in which similar
elements in different drawings bear the same reference
numerals.
DETAILED DESCRIPTION OF THE INVENTION
[0038] In accordance with the embodiments of the invention
disclosed herein, successive pairs of reclosable packages are
manufactured using only one web of bag making film, the bags of
each pair being manufactured side-by-side and concurrently. The
process starts with unwinding a web of bag making film from a roll
and threading it through a form-fill-seal machine. Coming off of
the roll, the web is pulled under tension in a generally horizontal
plane. The tensioned film is folded along three mutually parallel
lines or zones to form a generally W-shaped profile, as will be
described in more detail below. Zippers for two lines of bags are
attached to the bag making film before or after folding or in
between separate folding operations. The two halves of the triply
folded web of bag making film are then cross-sealed at regular
intervals to form a chain or series of receptacles. Successive
pairs of receptacles--one receptacle from each chain--are filled
with product. Then the open ends of the filled bags are closed. The
dual manufacture of reclosable packages doubles the capacity of a
form-fill-seal machine.
[0039] The bag making film may be made of a suitable plastic film
material for the product to be contained within the package. For
example, the film may be a laminate or coextrusion comprising a gas
barrier layer and/or a low-melting-point sealant layer. The zipper
strips are sealed to the bag making film by permanent seals. It
should be appreciated that each permanent seal is a band of joined,
e.g., fused, material that extends from one side seal of the bag to
the other side seal, thereby securing the zipper to the bag along
the width of the bag. The permanent seals are generally parallel to
each other and may be formed by any conventional method, such as
conduction heat sealing. The invention has application with both
slider-operated and sliderless zippered bags. In the former case,
the slider is mounted to the profiled closure members of the zipper
to facilitate zipper opening and closing in a well-known manner.
For proper functioning, the interlockable closure members may have
spot seals or ultrasonic stomps at the ends of the zipper halves.
These seals ensure the zipper strips will not come apart during use
and provide end stops for stopping the slider. The slider 8 is
preferably made of a resilient plastic material, such as delrin,
polypropylene, PBT, etc. Prior to opening of the package by the
consumer, the slider-zipper assembly is frequently covered on the
consumer side by an enclosed header that is hermetically sealed.
The sealed header provides a tamper-evident feature. Peel seals
below or above the zippers may also be provided.
[0040] FIGS. 1 and 2 show one embodiment of the invention at two
stages in the manufacturing process. Two zipper tapes are installed
in respective folds of a folded web of bag making film. The zippers
are of the webless or so-called "string" variety, meaning that they
do not have webs or flanges extending to one side of the profiled
closure members. However, sliderless webbed zippers may also be
used. A webless or string zipper is attached to bag making film in
the base areas of the interlocking closure elements. FIG. 1 shows
the intermediate stage after the following steps have been
performed: (1) a pair of zipper tapes 4 and 4' are placed atop a
flat tensioned web 2 of bag making film aligned with the machine
direction (out of the page); (2) the bases of the zipper strips 18
and 18' are sealed or otherwise joined to the web 2 along parallel
bands or zones; (3) the web 2 is folded along lines or zones
parallel to the foregoing zones of zipper strip joinder to form
folds 6 and 6', with the folded portions of the web respectively
overlying the zipper tapes 4 and 4'; and (4) the folded portions of
web 2 are sealed or otherwise joined to the bases of the zipper
strips 20 and 20' of the respective zipper tapes. Although FIG. 1
depicts a gap separating the edges of the folded portions of the
web of bag making film, the edges may meet or overlap each other.
In FIG. 1, the profiled closure members of the zipper tapes are
depicted as having male and female profiles. However, the profiles
of the interlocking closure elements need not be of the male/female
variety. Any type of interlocking elements, e.g., interlocking
hooks, may be utilized.
[0041] The precursor structure shown in FIG. 1 is folded along a
central zone 8 to form the triply folded structure depicted in FIG.
2. It should be noted that the central fold 8 is formed by folding
the bag making film in a direction opposite to that by which folds
6 and 6' were formed. As seen in FIG. 2, the folded web 2 reverses
its direction along the folds 6', 8 and 6 to form a serpentine
cross-sectional profile with first and second walls 10 and 12 on
one side of central fold 8, and third and fourth walls 14 and 16 on
the other side of the central fold 8. The bottoms of walls 10 and
12 are connected along fold 6; the tops of wall 12 and 16 are
connected along central fold 8; and the bottoms of walls 14 and 16
are connected along fold 6'. The zipper tape 4 is disposed between
walls 10 and 12 near fold 6, while the zipper tape 4' is disposed
between walls 14 and 16 near fold 6'. In the configuration shown in
FIG. 2, both sides of the W-shaped structure can be cross-sealed
(not shown) and then filled through the open bottoms of the
receptacles formed by cross sealing, i.e., the interior volumes of
the receptacles are filled behind the zippers. Then the bottoms of
the packages are sealed and a cut 56 is made in fold 8 to sever
each pair of filled packages from each other. The respective filled
packages at the termini of the respective chains of packages are
then severed from the respective chains to form a pair of severed
completed packages (not shown).
[0042] In the embodiment depicted in FIGS. 1 and 2, the zipper
tapes were placed on the flat web of bag making film at locations
proximal to the outer zones of folding, giving rise to the
precursor structure of FIG. 2 in which the zipper tapes are
situated near the bottoms of the U-shaped web troughs. The folded
portions 6 and 6' of bag making film serve as headers that provide
evidence of tampering with the package. Although not shown in FIG.
2, lines of weakness (such as perforation or laser score lines) can
be provided in conventional fashion to aid the tearing away of the
header, thereby allowing access to the zipper inside.
[0043] Alternatively, the zipper strips can be placed proximal to
and on opposite sides of the central folding zone, so that the
zipper tapes will be situated near the tops of the troughs and
adjacent to the central fold 8. In accordance with another method
of manufacture, the folded portions of central fold 8 and the outer
edges or adjacent area of the web are sealed to the adjoining
zipper strips, in which case the zippers must later be opened in
order to fill the receptacles formed by cross sealing. This can be
accomplished by separating the zipper strips and adjoining web
portions, e.g., by means of a separating finger or plow positioned
between the zipper strips. In accordance with another method of
manufacture, the outer edges of the web are not sealed to the
adjoining zipper strips, in which case the receptacle formed later
by cross sealing can be filled by pulling the opposing edges of the
folded-over web portions away from the zipper tapes and filling the
receptacle through the gaps between the web portions and the zipper
tapes. Alternatively, if the zippers are slider operated, then the
sliders may be used to open the zipper for filling the receptacle
and closing it thereafter.
[0044] In accordance with yet another variation, the zipper strips
of the respective zipper tapes can be separately joined to the web
of bag making film. One pair of zipper strips are sealed in
parallel to the machine direction at respective locations proximal
to and on opposite sides of the central folding zone, while another
pair of zipper strips are sealed in parallel to the first pair of
zipper strips at locations proximal to the edges of the web of bag
making film. On each half of the web, the inner and outer zipper
strips are equidistant from the location where that half of the web
will be folded over. In this case the web is folded on both sides
and then the zipper strips at the web edges are interlocked with
the more centrally located zipper strips. In accordance with a
further variation, instead of joining four separate zipper strips
to the web of bag making film, the profiled closure members can be
integrally formed with the bag making film, e.g., by extrusion. In
yet another variation, the zipper strips are sealed to the folded
web inside the web folds at the same time. In such an instance,
separating plates may be inserted between the zipper strip flanges
to prevent seal-through.
[0045] FIGS. 3 and 4 depict precursor structures for reclosable
packaging comprising slider-operated zippers installed at the open
tops of the U-shaped folded portions of the web 4. The sliders 25
can be inserted before the zipper tapes 22 and 22' are attached to
the web 4 of bag making film or after zipper attachment and folding
of the web. Each zipper tape comprising a pair of interlocked
zipper strips. For zipper tape 22, one zipper strip comprises a
profiled closure member 24 and a flange 28 having one end connected
thereto, and the other zipper strip comprises a profiled closure
member 26 and a flange 30 having one end connected thereto. For
zipper tape 22', one zipper strip comprises a profiled closure
member 25 and a flange 32 having one end connected thereto, and the
other zipper strip comprises a profiled closure member 27 and a
flange 34 having one end connected thereto. The profiles of the
closure members may have any known configuration, e.g.,
male/female, interlocking hooks, etc.
[0046] FIG. 3 shows the intermediate stage after the following
steps have been performed: (1) a pair of zipper tapes 22 and 22'
are placed atop a flat tensioned web 2 of bag making film aligned
with the machine direction; (2) the flange 30 of one zipper strip
and the flange 34 of the other zipper strip are sealed or otherwise
joined to the web 2 along parallel bands or zones; (3) the web 2 is
folded along lines or zones parallel to the foregoing zones of
flange joinder to form folds 6 and 6', with the folded portions of
the web respectively overlying the zipper flanges 28 and 32; and
(4) the folded portions of web 2 are sealed or otherwise joined to
the zipper flanges 28 and 32. Although FIG. 3 depicts the edges of
the folded portions of the web of bag making film as not extending
beyond the zipper flanges to which they are attached, the folded
portions of the web may extend beyond the zipper tapes for later
use in the formation of tamper-evident headers for the packages (as
will be described later with reference to FIG. 20). Alternatively,
zipper tapes 22 and 22' can be introduced between the already
folded film with flanges 28, 30 and 32,34 being sealed at the same
time to the respective film web areas. In such an instance,
separating plates may be positioned between mutually opposed
flanges to prevent seal-through, as will be described in more
detail later with reference to FIG. 21.
[0047] The precursor structure shown in FIG. 3 is folded along a
central zone 8 to form the triply folded structure depicted in FIG.
4, the folding operation being substantially similar to that
previously described in connection with FIG. 2. As seen in FIG. 4,
the folded web 2 reverses its direction along the folds 6', 8 and 6
to form a serpentine cross-sectional profile similar to that
previously described with reference to FIG. 2, with first and
second walls 10 and 12 on one side of central fold 8, and third and
fourth walls 14 and 16 on the other side of the central fold 8. The
zipper tapes 22 and 22' with sliders 25 project upward on opposite
sides of the central fold 8 of the inverted U-shaped precursor
structure.
[0048] In the configuration shown in FIG. 4, both sides of the
W-shaped structure can be cross-sealed to form individual
receptacles. The slider on each zipper segment corresponding to a
receptacle to be filled is then mechanically moved from the closed
position to the open position, thereby opening the formed
receptacle for filling. The interior volumes of the receptacles are
filled through the open zippers. The sliders are then used to close
the zipper. Alternatively, the slider is kept stationary and the
zipper is moved through the slider to open it before filling and is
then mechanically closed after filling. Then the zippers are
closed. Following the filling operation, the two chains of filled
receptacles are advanced one package increment. During this
advance, a cut 56 is made in fold 8 to sever the pair of filled
packages at the termini of the chains from each other. The
respective filled packages of this terminal pair are then severed
from the respective chains to form a pair of severed completed
packages.
[0049] Any of the packages disclosed herein can be provided with
tamper-evident features, such as a peel seal inside the interior of
the package. For the purpose of illustration, alternative
tamper-evident features are shown in FIG. 4. In accordance with a
first alternative, opposing zipper flanges of each zipper tape may
be sealed together by a respective peel seal 90, indicated by small
dashed rectangles in FIG. 4. The peel seal material can be applied
on one of the zipper flanges before the zipper tapes are joined to
the bag making film. The peel seal can be formed by pressing the
zipper flanges together while applying sufficient heat to activate
the peel seal material. Such a peel seal must be broken or ruptured
in order to gain access to the interior volume of the package,
thereby leaving evidence that warns a consumer that the package has
been tampered with. In accordance with a second alternative, the
zipper flanges of each zipper tape may be connected by an
integrally formed web or membrane 52, which is indicated by dotted
curved lines in FIG. 4. In this case, each web 52 has a line of
weakness (not shown) to facilitate tearing or rupture of the web in
a preferred direction generally parallel to the zipper.
[0050] In accordance with further alternatives, the final packages
can be provided with headers that form enclosed volumes above the
zippers to prevent tampering with the contents of the package. In
the case of the embodiment depicted in FIG. 4, respective header
webs can be folded over and attached to the tops of the respective
chains of receptacles after cutting along line 56. Alternatively,
the web of bag making film is wide enough and the zipper tapes are
positioned such that after cutting along line 56, the edges of the
web of bag making film can be sealed together to form respective
headers over the zippers. Instead of the bag making film being
sealed to itself at the apex of the header, a strip of peel seal
material could be placed between the opposing edges of the web to
join them together, as will be described in more detail later with
reference to FIG. 20. The foregoing header configurations have
equal application in the context of the other embodiments described
below in which the zippers are installed at the tops of the folded
web and not in the folded bottoms of the web of bag making
film.
[0051] In connection with the embodiment of FIGS. 1 and 2, a
variation was described in which the zipper tapes would be placed
on the web of bag making film along mutually parallel zones located
proximal to and on opposite sides of the central folding zone. FIG.
5 shows a further variant wherein two of the four zipper strips are
connected to form a zipper strip 36 having two mutually parallel
profiled closure members projecting from the same side of an
extended base. Each closure member on strip 36 is interlocked with
a respective complementary closure member of a respective zipper
strip 20 or 20'. The strip 36 (carrying interlocked strips 20 and
20') is sealed or otherwise joined to a central zone of the web 2
of bag making film and then the outer sections of the web are
folded over the zipper strips 20 and 20' and sealed thereto.
[Alternatively, the zipper strips 20 and 20' could be joined to the
web 2 near the edges of the latter and then interlocked with the
closure members of strip 36 when the outer sections of the web are
folded over.] The result of these method steps is depicted in FIG.
5. Then the web 2 and strip 36 are folded in the middle to form
fold 8, as seen in FIG. 6, the folding action being in a direction
opposite to that of folds 6 and 6'. While in the upright position
shown in FIG. 6, both U-shaped halves of the folded web of bag
making film are cross sealed to form respective chains or series of
receptacles. The zippers of each successive pair of side-by-side
receptacles can be opened to enable the receptacles to be filled.
Again, this can be accomplished by separating the zipper strips 20
and 20' and adjoining strip 36 e.g., by means of a separating
finger positioned between the strips, as will be described in more
detail later with reference to FIGS. 22 and 23. Then the respective
zippers on the most recently filled pair of receptacles are closed
and the projecting top edges of the bag making film can be sealed
together to form headers over the zippers in conventional manner.
Then the completed packages can be severed from the respective
chains of receptacles by transverse cutting, as previously
described.
[0052] In accordance with an alternative method of manufacture, the
edges or adjacent area of the folded-over portions of the web are
not sealed to the zipper strips 20 and 20' until after filling, in
which case the receptacle formed later by cross sealing can be
filled by pulling the opposing edges of the folded-over web
portions away from the adjoining zipper strips and filling the
receptacle through the gaps between the web portions and the zipper
strips. Thereafter the adjacent portions of the bag making film are
sealed or otherwise joined to the zipper strips 20 and 20'.
[0053] FIG. 7 depicts another embodiment of a precursor structure
in which respective parts of two zipper tapes (with sliders 25
inserted thereon) are connected by an integrally formed web or
membrane 38, forming a hinged zipper assembly. As best seen in FIG.
8, one end of the web 38 and one end of a zipper flange 34 are
connected at a first hinge line 36', while the other end of the
zipper flange 34 is connected to a profiled closure member of one
slider-operated zipper 22'. The other end of the web 38 and one end
of a zipper flange 30 are connected at a second hinge line 36',
while the other end of the zipper flange 30 is connected to a
profiled closure member of the other slider-operated zipper 22.
This zipper structure is integrally formed. Each hinge line may
comprise a corner section having necked or narrowed segments that
meet at a vertex 37 (see FIG. 9) to form a profile that flexes from
a relatively open configuration to a relatively closed
configuration as the hinged zippered structure is bent and folded
into the generally W-shaped configuration seen in FIG. 7.
[0054] The central web 38 is sealed or otherwise joined to a
central zone of the web of bag making film and then folded as shown
to form the central inverted fold 8. In addition, a pair of zipper
strips, each comprising a profiled closure member and a zipper
flange having one end connected to the profiled closure member, is
attached to parallel outer portions of the web of bag making film.
The zipper strips are located and oriented so that when the outer
section of the web are folded over, the closure members of the
zipper strips can be interlocked with the closure members of the
central zippered structure, as seen in FIG. 8. The zipper flange 28
of one zipper strip is sealed to a portion of the web that becomes
part of wall 14, while the zipper flange 32 of the other zipper
strip is sealed to a portion of the web that becomes part of wall
10. In this embodiment, the receptacles formed by cross sealing can
be opened by mechanically moving the sliders relative to the
zippers and then the open receptacles are filled. Then the zippers
of the filled receptacles can be closed, again by mechanically
moving the slider, and separate filled packages can be severed from
the respective chains by cutting. Alternatively, as indicated
previously, the slider can be stationary while the zipper is moved
through the slider to open the receptacle.
[0055] In accordance with a variation of the embodiment shown in
FIG. 7, the opposing zipper flanges of each zipper can be connected
by an integrally formed web or membrane 52, indicated by dashed
curved lines in FIG. 7. These webs or membranes provide a
tamper-evident feature.
[0056] FIGS. 10 and 11 depict an embodiment of the invention
wherein the entire double-zippered structure 40 is integrally
formed. The integrally formed zippered structure 40 comprises a web
42 and first through fourth profiled closure members connected to
the web 42. The closure members are disposed generally in parallel
with each other, the first closure member 48 being interlocked with
the second closure member 44, and the third closure member 50 being
interlocked with the fourth closure member 46. The web 42 comprises
first and second web portions connected by a third web portion. In
the particular example depicted in FIG. 10, the third web portion
extends from the base of the male closure member 48 to the base of
the male closure member 50. The first web portion extends from one
zone connected to closure member 44 to another zone connected to
the closure member 48 (and to the third web portion), while the
second web portion extends from one zone connected to closure
member 46 to another zone connected to closure member 50 (and to
the third web portion). The double-zippered structure 40 can be
made by extruding a planar web with the four profiled closure
members running in parallel at spaced intervals along the length of
the web. Then the outer sections of the web are folded over and the
opposing closure members are interlocked as seen in FIG. 10. Before
folding, two lines of weakness 54 can be formed in the web, the
lines of weakness being placed on the web such that they lie at the
cusp of the folds when the web 42 is folded. Each line of weakness
may comprise a line of perforations covered by a thin sealing strip
or a score line formed by a laser beam.
[0057] As seen in FIG. 10, the spine of the zippered structure 42
is sealed or otherwise joined to a flat web 2 of tensioned bag
making film. The zippered structure 42 can be joined along one or
more zones of joinder. Multiple zones of joinder are mutually
parallel. The resulting structure is then folded three times along
mutually parallel zones of folding 6, 6' and 8, to arrive at the
configuration shown in FIG. 11. After the outer sections of web 2
are folded over to form folds 6 and 6', the folded-over web
portions overlapping zipper closure members 44 and 46 are not yet
joined to the respective adjacent portions of zipper web 42. Before
or after the aforementioned folding steps, the central portions of
the web 2 of bag making film and the zipper web 42 are folded in
the opposite direction to form an inverted (i.e., upside down) U
shape that connects the U shapes formed by folds 6 and 6'. While in
the upright position shown in FIG. 11, both U-shaped halves of the
folded web of bag making film 2 first have their outer sections
sealed to the adjacent portions of zipper web 42 and then are cross
sealed to form respective chains or series of receptacles. The
zippers of each successive pair of side-by-side receptacles can be
opened to enable the receptacles to be filled. Again, this can be
accomplished by separating closure member 44 from 48 and closure
member 46 from 50 by means of a separating finger. In accordance
with another method of manufacture, the folded-over portions 6 and
6' of the web are not sealed to the adjoining zipper strips 20 and
20' until after filling, in which case the receptacles subsequently
formed by cross sealing can be filled by pulling the opposing edges
of the folded-over web portions away from the adjoining zipper
strips and filling the receptacle through the gaps between the web
portions and the zipper strips. In either case, after the filling
operation, the respective chains of receptacles are severed from
each other and then respective completed packages are severed from
the respective chains of receptacles. Optionally, tamper-evident
headers can be made (in any one of the ways previously described)
before the cutting operations.
[0058] In accordance with an alternative embodiment, the webless
zippers of the embodiment shown in FIG. 2 can be replaced by
flanged zippers operated by sliders, the latter being placed upside
down proximal to the bottom folds in the generally W-shaped folded
web of bag making film. The zipper tapes with sliders can be joined
to the web of bag making film either before or after folding of the
bag making film. To illustrate one embodiment of a dual-capacity
HFVF machine, the embodiment wherein the zipper tapes are joined to
the web of bag making film before folding will now be described
with reference to FIGS. 12-18.
[0059] FIG. 12 depicts a flat horizontal web 2 of bag making film
being folded along a pair of parallel fold lines 6 and 6' as it
advances in a machine direction. This can be accomplished using a
folding board (not shown). The web 2 entering this folding station
carries two zipper tapes 22 and 22', each zipper tape having a
multiplicity of sliders 25 inserted thereon. The sliders 25 are
spaced at equal intervals, one slider for each length of bag making
film equal to the width of the final package. In this example, each
zipper strip of the respective zipper tapes comprises a respective
profiled closure member and a respective zipper flange having one
end connected to the respective closure member. The closure members
of each zipper tape have complementary mating profiles. In the top
view of FIG. 12, only zipper flanges 28 and 32 of zipper tapes 22
and 22' are visible, although it should be understood the a
respective lower zipper flange lies directly below the zipper
flanges 28 and 32. At a first sealing station, a lower sealing bar
(not visible in FIG. 12) and an upper pressure plate 60 located
directly above the lower sealing bar and between the zipper flanges
apply pressure and conductive heat to seal the lower zipper flange
(not visible) of zipper tape 22 to the web 2, while another upper
pressure plate 60' and another lower sealing bar (not visible in
FIG. 12) located directly below upper pressure plate 60' apply
pressure and conductive heat to seal the lower zipper flange (not
visible) of zipper tape 22' to the web 2. In this example, the
zipper tapes are aligned with the machine direction and disposed
between the fold lines 6 and 6' with zipper flanges pointing toward
the center of the web 2. Ultimately, the fold lines 6 and 6' will
form the apices of headers on the tops of the final packages.
Immediately after the first sealing station, the outer sections of
the web 2 of bag making film are folded over the zipper tape, as
seen in FIG. 12. For the purpose of this example, it is assumed
that the bag making film is optically transparent, so that the
portions of the zipper tape lying underneath the folded-over
portions of the web 2 are visible in FIG. 12. At a second sealing
station, an upper sealing bar 62 and a lower pressure plate (not
visible in FIG. 12) located directly below sealing bar 62 and
between the zipper flanges apply pressure and conductive heat to
seal zipper flange 28 of zipper tape 22 to the opposing folded-over
portion of web 2, while another upper sealing bar 62' and a lower
sealing bar (not visible in FIG. 12) located directly below sealing
bar 62' apply pressure and conductive heat to seal zipper flange 32
of zipper tape 22' to the opposing folded-over portion of web 2.
The web of bag making film then advances to the next station.
[0060] At the next station, the web 2 of bag making film is
converted from a horizontal position to a vertical position. In the
process, the web 2 is folded along a centerline to form the
generally W-shaped profile shown in FIG. 15. More specifically, the
web 2 is folded against and wrapped around an upright support plate
82, which preferably has a profile comprising substantially
mutually parallel planar side walls, the surfaces of which are
connected by a circular semi-cylindrical surface at the upper end
of the support plate. The axis of the semi cylindrical surface of
support plate 82 is aligned in the machine direction, i.e., the
direction in which the web of bag making film advances during this
stage of manufacture.
[0061] Referring to FIGS. 13 and 14, the folded web 2 with zipper
tapes attached and with sliders 25 inserted at spaced intervals
along the zipper tapes is pulled forward by a pair of upright
grooved drive rolls 64 arranged in opposition to opposing side
walls of the support plate 82. Respective portions of the generally
W-shaped web pass between respective nips formed between the drive
rolls 64 and the support plate 82 disposed therebetween. The
annular grooves in the drive rolls 64 have a width greater than the
height of the sliders 25 and are vertically positioned to allow the
sliders to pass through the grooves when the web of bag making film
with attached zipper tape is advanced. The hatched band-shaped area
designated 58 indicates the zipper flange-to-film permanent seals
formed at the first and second sealing stations, previously
described.
[0062] At a third sealing station, a vertical sealing bar 66 and a
vertical sealing bar (not visible in FIG. 10) located directly
behind sealing bar 66 apply sufficient pressure and conductive heat
to form transverse or cross seals 76 at spaced intervals along the
length of the web. Each cross seal 76 is a band-shaped zone, which
is subsequently bisected when the completed package is severed from
the chain, thereby forming side seals on two packages. The cross
seals in combination with the bottom folds form respective
receptacles that are filled at a filling station having a pair of
fill tubes or spouts 70. The unsealed ends of the respective
receptacles at the filling station are opened wider by means of a
pair of retractable suction or vacuum-activated cups 68. The cups
68 are advanced into position in abutment with the outer walls of
the W-shaped web of bag making film, the suction or vacuum is
applied, and then the cups 68 are retracted while holding the web
walls, causing the outer walls to spread outward, as seen in FIG.
14. The product is then poured through the fill tubes 70 and into
the respective receptacles, as depicted in FIG. 16. When the
receptacle is filled with product, the vacuum cups are returned to
their original positions and the vacuum is released. Then the
filled receptacle is advanced to another sealing station where the
open top of the receptacle (which will be the bottom of the
completed package) is sealed. At the fourth sealing station, a pair
of horizontal sealing bars 72 apply sufficient pressure and
conductive heat to form a horizontal seal across the top of the
web, thereby closing the respective receptacles. FIG. 17 shows the
seal bars 72 in their retracted positions. When they are extended,
the top edges of the two separated receptacles are sealed. It
should be noted that the sealing bars at the third and fourth
stations press the web of bag making film against the sides of the
support plate 82. After the top sealing operation, the web is
advanced. During this advance, the top sealed filled receptacle is
cut along the central fold 8 by a knife 84. To advance the
receptacles now separated by knife 84, rollers 94 on either side of
the support plate 82, positioned at a slant if so required (see
FIG. 18), in conjunction with belts 92 under the filled
receptacles, move the receptacles through the fourth sealing
station. Additional rollers can be located at different positions
in the HFVF machine either on the sides of the web or above, as
indicated previously, to move the web through the other positions.
Finally, the completed packages are severed from the respective
chains of receptacles by a pair of knives 74 that cut through the
center of seal 76 (see FIGS. 13 and 14).
[0063] In accordance with an alternative embodiment shown in FIG.
19, the cross seal bars do not reach the top edges of the folded
web of film and the film passes on both sides of each fill spot 70.
In this case, the seal bars 72' are wider. The resulting bottom
seal is indicated by the hatched region designated by the numeral
86.
[0064] In accordance with a further embodiment of the invention,
slider-operated zippers can be installed on either side of the
central fold instead of proximal to the outer folds of the
generally W-shaped web 2 of bag making film. This situation is
depicted in FIG. 20, wherein numerals 22 and 22' designate the
respective zipper tapes installed between the walls of the folded
web. Strips 90 of peel seal material are joined to one wall of each
side of the W-shaped web 2. Before the knife 84 severs the two
sides of the folded web from each other, the horizontal seal bars
72 activate the peel seal. FIG. 20 shows the seal bars 72 in the
retracted position and the peel seal material 90 not yet
activated.
[0065] In many of the methods of manufacture disclosed hereinabove,
zipper strips are attached to the web of bag making film before the
web is folded. Alternatively, the web of bag making film can be
folded to have the above-described generally W-shaped serpentine
profile and then the zipper strips are inserted in between the
folded portions and sealed to the web, as shown in FIG. 21, by
outside seal bars 72 and opposing seal bars 73 contained within the
support plate 82. This is followed by cross sealing, filling and
cutting as previously described. In such an instance, separating
plates 96 can be introduced between the zipper flanges to prevent
seal through when sealing the flanges to film web 2. If the zippers
do not have flanges, being sealed to the film by their base, their
interlocking elements can be separated by a separating plate 98
introduced between the interlocking elements in the sealing area
and then being rejoined by a pair of rollers 100, as shown in FIGS.
22 and 23.
[0066] While the invention has been described with reference to
preferred embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for members thereof without departing from the scope of
the invention. In addition, many modifications may be made to adapt
a particular situation to the teachings of the invention without
departing from the essential scope thereof. Therefore it is
intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out
this invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
[0067] As used in the claims, the verb "joined" means fused,
bonded, sealed, adhered, etc., whether by application of heat
and/or pressure, application of ultrasonic energy, application of a
layer of adhesive material or bonding agent, interposition of an
adhesive or bonding strip, etc. As used in the claims, the term
"zipper tape" comprises either a pair of zipper strips comprising
respective interlocked profiled closure members or a monolithic
structure comprising a pair of interlocked profiled closure members
connected by a folded web or membrane.
* * * * *