U.S. patent application number 10/340421 was filed with the patent office on 2006-06-08 for watertight slider-zipper assembly for reclosable packaging.
Invention is credited to Steven Ausnit, Eric Paul Plourde.
Application Number | 20060120630 10/340421 |
Document ID | / |
Family ID | 32711327 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060120630 |
Kind Code |
A9 |
Ausnit; Steven ; et
al. |
June 8, 2006 |
Watertight slider-zipper assembly for reclosable packaging
Abstract
A slider-zipper construction that provides a watertight seal
below the interlocked zipper profiles on the product side of the
zipper. The seal comprises at least one seal part that is
compressible or at least partially collapsible. The slider is
designed to compress or at least partially collapse that seal part
in the area below the plow of the slider, where the zipper profiles
cannot be interlocked due to the interference of the plow.
Inventors: |
Ausnit; Steven; (New York,
NY) ; Plourde; Eric Paul; (Homewood, IL) |
Correspondence
Address: |
OSTRAGER CHONG FLAHERTY & BROITMAN PC
250 PARK AVENUE, SUITE 825
NEW YORK
NY
10177
US
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Prior
Publication: |
|
Document Identifier |
Publication Date |
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US 20040136618 A1 |
July 15, 2004 |
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Family ID: |
32711327 |
Appl. No.: |
10/340421 |
Filed: |
January 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09949081 |
Sep 10, 2001 |
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10340421 |
Jan 10, 2003 |
|
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09462101 |
Jan 13, 2000 |
6761481 |
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PCT/FR99/01455 |
Jun 17, 1999 |
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09949081 |
Sep 10, 2001 |
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Current U.S.
Class: |
383/64 |
Current CPC
Class: |
B65D 33/2591
20130101 |
Class at
Publication: |
383/064 |
International
Class: |
B65D 33/16 20060101
B65D033/16 |
Claims
1. A slider-zipper assembly comprising a zipper and a slider
mounted to said zipper, wherein said zipper comprises first and
second zipper parts and said slider comprises a plow for separating
opposing sections of said first and second zipper parts to open
said zipper, said first zipper part comprising a first base strip,
a first profiled closure member supported by said first base strip
and a first sealing structure supported by said first base strip,
and said second zipper part comprising a second base strip, a
second profiled closure member supported by said second base strip
and a second sealing structure supported by said second base strip,
wherein said first and second profiled closure members are mutually
interlockable for closing sections of said zipper during slider
movement, said first sealing structure is compressible or at least
partially collapsible, and said first and second sealing structures
contact each other in closed sections of said zipper and an open
section of said zipper penetrated by said plow of said slider.
2. The assembly as recited in claim 1, wherein said slider is
designed to exert a pressure that compresses or at least partially
collapses at least a portion of said first sealing structure that
is disposed beneath said plow.
3. The assembly as recited in claim 1, wherein said second sealing
structure is compressible or at least partially collapsible.
4. The assembly as recited in claim 1, herein said first sealing
structure is made of different material than said first base
strip.
5. The assembly as recited in claim 1, wherein said first sealing
structure is hollow.
6. The assembly as recited in claim 5, wherein said first sealing
structure is a hollow tube joined along a peripheral zone to said
first base strip.
7. The assembly as recited in claim 5, wherein said first sealing
structure is C- or U-shaped and is joined to or integrally formed
with said first base strip.
8. The assembly as recited in claim 5, wherein said second sealing
structure is hollow.
9. The assembly as recited in claim 5, wherein said second sealing
structure is foamed material.
10. The assembly as recited in claim 5, wherein said second sealing
structure is a body of plastomeric material.
11. The assembly as recited in claim 5, wherein said first sealing
structure and said first base strip are made of the same
material.
12. The assembly as recited in claim 1, wherein said first sealing
structure is foamed material.
13. The assembly as recited in claim 12, wherein said second
sealing structure is foamed material.
14. The assembly as recited in claim 1, wherein said first sealing
structure is a body of plastomeric material.
15. The assembly as recited in claim 14, wherein said second
sealing structure is a body of plastomeric material.
16. The assembly as recited in claim 1, wherein said first base
strip is made of a first material having a first modulus of
elasticity, and said first sealing structure is made of a second
material having a second modulus of elasticity less than said first
modulus of elasticity.
17. A reclosable package comprising a receptacle and an assembly as
recited in claim 1, wherein said zipper of said assembly is joined
to or integrally formed with said receptacle.
18. A slider-zipper assembly comprising a zipper and a slider
mounted to said zipper, wherein said zipper comprises first and
second zipper parts and said slider comprises a plow for separating
opposing sections of said first and second zipper parts to open
said zipper, said first zipper part comprising a first base strip,
a first profiled closure member supported by said first base strip
and a sealing structure supported by said first base strip, and
said second zipper part comprising a second base strip and a second
profiled closure member supported by said second base strip,
wherein said first and second profiled closure members are mutually
interlockable for closing sections of said zipper during slider
movement, and said sealing structure is compressible or at least
partially collapsible and contacts said second base strip along
closed sections of said zipper and an open section of said zipper
penetrated by said plow of said slider.
19. The assembly as recited in claim 18, wherein said slider is
designed to exert a pressure that compresses or at least partially
collapses at least a portion of said sealing structure that is
disposed beneath said plow.
20. The assembly as recited in claim 19, wherein said sealing
structure is hollow.
21. The assembly as recited in claim 20, wherein said sealing
structure is a hollow tube joined along a peripheral zone to said
first base strip.
22. The assembly as recited in claim 20, wherein said sealing
structure is C- or U-shaped and is joined to or integrally formed
with said first base strip.
23. The assembly as recited in claim 20, wherein said sealing
structure and said first base strip are made of the same
material.
24. The assembly as recited in claim 19, wherein said sealing
structure is foamed material.
25. The assembly as recited in claim 19, wherein said sealing
structure is a body of plastomeric material.
26. The assembly as recited in claim 19, wherein said first base
strip is made of a first material having a first modulus of
elasticity, and said sealing structure is made of a second material
having a second modulus of elasticity less than said first modulus
of elasticity.
27. A reclosable package comprising a receptacle and an assembly as
recited in claim 18, wherein said zipper of said assembly is joined
to or integrally formed with said receptacle.
28. A reclosable package comprising a receptacle and a
slider-zipper assembly comprising a zipper joined to or integrally
formed with said receptacle and a slider mounted to said zipper,
wherein said zipper comprises first and second interlockable
profiled closure members, and said slider comprises a plow for
separating opposing sections of said first and second profiled
closure members to open said zipper, further comprising a
substantially watertight seal extending the width of said package
and disposed inside said receptacle on the product side of said
profiled closure members, said seal comprising a first seal part
that is compressible or at least partially collapsible, wherein
said slider is designed to exert a pressure that compresses or at
least partially collapses at least a portion of said first seal
part that is disposed beneath said plow.
29. The package as recited in claim 28, wherein said zipper
comprises first and second flanges joined to said receptacle.
30. The package as recited in claim 28, wherein said zipper
comprises first and second base strips respectively supporting said
first and second profiled closure members and joined to said
receptacle in areas behind said closure members.
31. The package as recited in claim 28, wherein said first seal
part comprises a hollow structure.
32. The package as recited in claim 28, wherein said first seal
part comprises foamed material.
33. The package as recited in claim 28, wherein said first seal
part comprises plastomeric material.
34. The package as recited in claim 28, wherein said seal further
comprises a second seal part that contacts said first seal part
along its entire length when said zipper is closed.
35. The package as recited in claim 34, wherein one or both of said
first and second seal parts comprises a hollow structure.
36. The package as recited in claim 34, wherein one or both of said
first and second seal parts comprises foamed material.
37. The package as recited in claim 34, wherein one or both of said
first and second seal parts comprises plastomeric material.
Description
BACKGROUND OF THE INVENTION
[0001] This invention generally relates to slider-operated zippers
for use in reclosable packaging, such as bags or pouches. In
particular, the invention relates to sliders of the type that have
a separating finger or plow.
[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 often
include a plastic zipper and a slider. Typically, the plastic
zippers include a pair of interlockable profiled members that 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] In one type of slider-operated zipper assembly, the slider
straddles the zipper and has a plow at one end that is inserted
between the profiles to force them apart as the slider is moved
along the zipper in an opening direction. The other end of the
slider is sufficiently narrow to force the profiles into engagement
and close the zipper when the slider is moved along the zipper in a
closing direction.
[0005] Reclosable bags having sliders with zipper-separating plows
have the characteristic that they are not completely leakproof when
the zipper is closed and the slider is in the zipper-closed park
position. Leakage is due to the fact that the zipper remains open
in the region in front of the slider plow, i.e., the zipper
profiles remain separated in the region between the sealed end of
the zipper and the slider plow, even though the rest of the zipper
is closed. However, watertightness of the reclosable package is
required in numerous applications, for example, in reclosable bags
used to store frozen foods.
[0006] There is a need for improvements in the design of
slider-zipper assemblies for reclosable packaging that ensure a
watertight receptacle, especially in the area directly beneath the
plow of the slider when the latter is in the zipper-closed park
position.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The invention is directed to a slider-zipper construction
that provides a watertight seal below the interlocked zipper
profiles on the product side of the zipper. The seal comprises at
least one seal part that is compressible or at least partially
collapsible. The slider is designed to compress or at least
partially collapse that seal part in the area below the plow of the
slider, where the zipper profiles cannot be interlocked due to the
interference of the plow. The zipper may have either a flanged or
flangeless (string) construction.
[0008] One aspect of the invention is a slider-zipper assembly
comprising a zipper and a slider mounted to the zipper, wherein the
zipper comprises first and second zipper parts and the slider
comprises a plow for separating opposing sections of the first and
second zipper parts to open the zipper, the first zipper part
comprising a first base strip, a first profiled closure member
supported by the first base strip and a first sealing structure
supported by the first base strip, and the second zipper part
comprising a second base strip, a second profiled closure member
supported by the second base strip and a second sealing structure
supported by the second base strip, wherein the first and second
profiled closure members are mutually interlockable for closing
sections of the zipper during slider movement, one or both of the
first and second sealing structures is compressible or at least
partially collapsible, and the first and second sealing structures
contact each other in closed sections of the zipper and an open
section of the zipper penetrated by the plow of the slider, the
slider being designed to exert a pressure that compresses or at
least partially collapses at least a portion of one or both of the
first and second sealing structures that is disposed beneath the
plow.
[0009] Another aspect of the invention is a slider-zipper assembly
comprising a zipper and a slider mounted to the zipper, wherein the
zipper comprises first and second zipper parts and the slider
comprises a plow for separating opposing sections of the first and
second zipper parts to open the zipper, the first zipper part
comprising a first base strip, a first profiled closure member
supported by the first base strip and a sealing structure supported
by the first base strip, and the second zipper part comprising a
second base strip and a second profiled closure member supported by
the second base strip, wherein the first and second profiled
closure members are mutually interlockable for closing sections of
the zipper during slider movement, and the sealing structure is
compressible or at least partially collapsible and contacts the
second base strip along closed sections of the zipper and an open
section of the zipper penetrated by the plow of the slider, the
slider being designed to exert a pressure that compresses or at
least partially collapses at least a portion of the sealing
structure that is disposed beneath the plow.
[0010] Other aspects of the invention include reclosable packages
comprising a receptacle and a slider-zipper assembly of one of the
types described in the preceding two paragraphs, wherein the zipper
is joined to or integrally formed with the receptacle.
[0011] A further aspect of the invention is a reclosable package
comprising a receptacle and a slider-zipper assembly comprising a
zipper joined to or integrally formed with the receptacle and a
slider mounted to the zipper, wherein the zipper comprises first
and second interlockable profiled closure members, and the slider
comprises a plow for separating opposing sections of the first and
second profiled closure members to open the zipper, further
comprising a substantially watertight seal extending the width of
the package and disposed inside the receptacle on the product side
of the profiled closure members, the seal comprising a seal part
that is compressible or at least partially collapsible, wherein the
slider is designed to exert a pressure that compresses or at least
partially collapses at least a portion of the seal part that is
disposed beneath the plow.
[0012] Other aspects of the invention are disclosed and claimed
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a drawing showing a sectional view of one type of
reclosable bag having a slider-operated zipper.
[0014] FIG. 2 is a drawing showing an isometric partially sectioned
view of a slider-zipper assembly in accordance with one embodiment
of the invention.
[0015] FIGS. 3 and 4 are drawings respectively showing open and
closed sections of the zipper of FIG. 2 in a region not being
straddled by the slider.
[0016] FIG. 5 is a drawing showing a fragmentary view of a
reclosable package having the slider-zipper assembly depicted in
FIG. 2. The slider is shown in the zipper-closed park position.
[0017] FIG. 6 is a drawing showing a sectional view of the
slider-zipper assembly depicted in FIG. 5, the section being taken
along the line designated 6-6 in FIG. 5.
[0018] FIGS. 7-11 are drawings showing closed sections of
respective zippers in accordance with other embodiments of the
invention.
[0019] FIG. 12 is a drawing showing a closed section of a string
zipper in accordance with yet another embodiment of the
invention.
[0020] FIG. 13 is a drawing showing a closed section of a
slider-operated zipper in accordance with another embodiment of the
invention.
[0021] 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
[0022] For the purpose of illustration, various embodiments of the
invention will be described with reference to a reclosable package
of the type depicted in FIG. 1. However, application of the
leakproofing techniques of the present invention is not limited to
reclosable bags of the type shown in FIG. 1. For example, the
zipper can be integrally formed with the bag making film, instead
of being joined to the bag making film. Further, the reclosable
package may be provided with a header that encloses the
slider-zipper assembly and acts as a tamper-evident feature.
Alternatively, the bag could be formed with side gussets, with or
without a bottom panel.
[0023] A conventional reclosable bag 10 having a flexible plastic
zipper 12 operated by manipulation of a slider 14 is shown in FIG.
1. The slider-zipper assemblies disclosed herein can be installed
in a reclosable bag of the type shown in FIG. 1 or other types of
reclosable packages having different structures. The bag 10 may be
made from any suitable sheet material or plastic film and comprises
opposite wall panels, which may be secured together at opposite
side edges of the bag by seams (not shown). The opposing bottoms of
the wall panels may be joined, for example, by means of a heat seal
made in conventional fashion, e.g., by application of heat and
pressure or ultrasonic energy. Typically, however, the bottom of
the package is formed by a fold in the original packaging film.
Optionally, the bag may be provided with side gussets having
respective junctures with the front and rear wall panels. In the
latter case, the bag may also be provided with a bottom panel
having respective junctures with the front and rear wall panels and
with the side gussets.
[0024] At its top end, the bag 10 has an openable mouth, on the
inside of which is an extruded plastic zipper 12. The zipper 12
comprises a pair of interlockable fastener strips or zipper halves.
The profiles of the zipper halves may take any form. For example,
the zipper may comprise interlocking rib and groove elements or
alternating hook-shaped closure elements. The preferred zipper
material is polyethylene.
[0025] The front and rear bag wall panels are respectively sealed
to the zipper halves 16 and 18 by heat fusion or welding.
Alternatively, the interlockable zipper halves can be attached to
the wall panels by adhesive or bonding strips or the zipper
profiles can be extruded integrally with the bag material. For the
purpose of joinder, each zipper half may be provided with a
respective extension flange, to which an upper portion of the
respective bag wall panel is fused or welded. The walls of the bag
may be formed of various types of thermoplastic material, such as
low-density polyethylene, substantially linear copolymers of
ethylene and a C3-C8 alpha-olefin, polypropylene, polyvinylidene
chloride, mixtures of two or more of these polymers, or mixtures of
one of these polymers with another thermoplastic polymer. The
person skilled in the art will recognize that this list of suitable
materials is not exhaustive.
[0026] In zippered bags with sliders, as the slider moves across
the zipper, the zipper is opened or closed. As shown in FIG. 1, the
slider 14 is slidable along the zipper in a closing direction "C",
causing the zipper halves to become engaged, or in an opening
direction "O", causing the zipper halves to become disengaged.
[0027] The slider 14 for opening or closing the reclosable zipper
is generally shaped so that the slider straddles the zipper
profiles. The ends of the slider are open to allow the zipper to
pass through. The opening end of the slider has a separating finger
or plow 15 that depends downward from the roof of the slider and
pries open the zipper profiles as the slider is moved in the
opening direction. Prior art sliders have been made in multiple
parts and welded together or the parts have been constructed to be
snapped together. Other known sliders have had a one-piece
construction. The slider parts can be made using any desired
method, such as injection molding. The slider can be molded from
any suitable plastic, such as nylon, polypropylene, polystyrene,
acetal, polyketone, polybutylene terephthalate, high-density
polyethylene, polycarbonate, or ABS.
[0028] A bag incorporating a zipper and a slider preferably
includes means, such as end stops (not shown in FIG. 1), for
preventing the slider from sliding off the end of the zipper when
the slider reaches the closed or fully opened position. Such end
stops perform dual functions, serving as stops to prevent the
slider from going off the end of the zipper and also holding the
two zipper profiles together to prevent the bag from opening in
response to stresses applied to the profiles through normal use of
the bag. The end stops may, for example, comprise stomped areas on
the zipper profiles themselves, riveted end clamps, plastic end
clips fused to the zipper, or any other suitable structure. The
stomped end stops can be sections of the profiles that are fused
together proximate to the open and closed slider positions such
that the end stops are raised. Stomping can be carried out by, for
example, applying heat and/or pressure or using ultrasonic
methods.
[0029] The zipper halves 16 and 18 preferably comprise interlocking
rib and groove elements, which are well known in the art. Many
configurations of rib and groove elements may be employed to
perform any one of a number of required functions. For instance,
specific rib and groove elements may be employed to permit the
package to be more easily opened from the outside than from the
inside, so that the tension produced by the contents of the package
will not accidentally open the rib and groove elements. Each zipper
half may comprise a respective zipper flange extension or web to
which the bag making film can be joined. Alternatively, each zipper
half may comprise a base strip that supports the respective
profiled closure member, the bag making film being attached to the
backs of the base strips. The latter zipper is commonly referred to
as a string zipper.
[0030] The invention relates to reclosable packages of the type
having a slider-operated zipper wherein the zipper profiles are
separated by a finger or plow carried by the slider. As previously
mentioned, such slider-zipper assemblies do not provide a
watertight seal in the zipper section penetrated by the slider plow
when the zipper is maximally closed.
[0031] As will be described hereinafter with reference to FIGS.
2-13, this problem is solved in accordance with various embodiment
s of the invention by providing a substantially watertight seal
extending the width of the reclosable bag and disposed inside the
bag on the product side of the profiled closure members of the
zipper. The seal comprises at least one part that is compressible
or at least partially collapsible along the length of the zipper,
while the slider is designed to exert additional pressure tot
compress or at least partially collapse at least a portion of the
seal part disposed beneath the plow of the slider.
[0032] FIG. 2 shows a slider-zipper assembly comprising a zipper
and a slider 14 mounted to the zipper. The zipper consists of two
zipper parts 16 and 18. The zipper part 16 comprises a base strip
17, a closure member 20 having a male profile and supported by the
base strip 17, and a sealing member 24 supported by the base strip
17. The base strip 17 includes a zipper flange extension 42
extending below the sealing member 24 for joinder of the bag making
film (not shown) that forms one wall of the bag. The zipper part 18
comprises a base strip 19, a closure member(s) 22 having a female
profile and supported by the base strip 19, and a sealing member 26
supported by the base strip 19. [The closure member having a female
profile may be formed by two hook-shaped members projecting from
the base strip, as seen in FIG. 2, or by a U- or C-shaped member,
also projecting from the base strip, that has its back integrally
formed with the base strip.] The base strip 19 includes a zipper
flange extension 44 extending below the sealing member 26 for
joinder of the bag making film that forms the other wall of the
bag. The sealing members 24 and 26 have C-shaped profiles, with the
ends of the C-shape integrally formed with the respective base
strips, thereby forming opposing hollow tube structures. These tube
structures may have a circular or elliptical profile and are
designed to deform when pressed together.
[0033] The profiled closure members 20 and 22 are interlockable to
close the zipper and disengageable to open the zipper. The state of
the zipper is controlled by operation of the slider 14, which can
move in either an opening or a closing direction. The slider
comprises a top wall and a pair of sidewalls projecting downward
from opposing edges of the top wall. The slider 14 further
comprises a plow 28 for separating opposing sections of the closure
members 20 and 22 to open the zipper during movement of the slider
in the opening direction (into the page in FIG. 2). The plow
projects vertically downward from the top wall and is disposed
generally midway between the sidewalls. The distal end of the plow
has retaining ledges 29 projecting in opposite directions to
maintain the slider on the zipper and prevent it from being pulled
off the zipper. The slider further comprises an opening end
(visible in FIG. 2), where plow 28 is disposed, and a closing end
(visible in FIG. 6). The gap separating those sections of the
slider sidewalls that are in line with the zipper profiles 20 and
22 decreases from the opening end to the closing end of the slider.
As a result, the slider sidewalls at the closing end press the
adjacent sections of the zipper profiles 20 and 22 into engagement
as the slider travels in the closing direction (out of the page in
FIG. 2).
[0034] In addition, as seen in FIGS. 2 and 6, the sidewalls of the
slider terminate in distal portions 30 and 32 that have offset
inwardly facing surfaces separated by a gap less than the width of
the zipper at the elevation of the sealing members 24 and 26 when
the sealing members are touching without compression. These offset
inwardly facing surfaces press sealing members 24 and 26 together,
causing them to compress or at least partially collapse. The gap
separating the distal portions 30 and 32 is preferably
substantially constant from the opening end to the closing end of
the slider. Thus, as seen in FIGS. 2 and 6, inside the slider the
distal portions 30 and 32 press together the sealing members 24 and
26, causing an increase in the area of contact at the interface of
the sealing members as the latter compress or partially collapse.
This zone of increased mutual abutment forms a watertight seal
beneath the plow 28, which intervenes between the zipper profiles.
In both of FIGS. 2 and 6, the slider and zipper are depicted with
gaps therebetween, but it should be understood that there are no
gaps between the distal portions 30 and 32 of the slider and
adjacent portions of the zipper.
[0035] While the distal portions 30 and 32 of the slider operate to
compress the sealing members 24 and 26 together, the portions of
the slider side walls at the elevations of the profiled closure
members have inwardly directed surfaces that converge in a
well-known manner for camming the zipper profiles into engagement
during movement of the slider in the closing direction (out of the
page in FIG. 2). The bottom edges of the slider side walls may be
provided with retaining ledges 50 and 52 at the closing end of the
slider for further increasing the slider pull-off resistance.
[0036] The sealing members 24 and 26, shown in FIGS. 2 and 6,
extend the full width of the zipper, so that the internal volume of
the bag can be sealed at an elevation below the zipper. FIG. 3
shows an open section of the zipper wherein the zipper profiles 20
and 22 are mutually disengaged and the sealing members 24 and 26
are also mutually disengaged. FIG. 4 shows a closed section of the
zipper after the slider has passed. In this situation, the zipper
profiles 20 and 22 are interlocked with each other, while the
sealing members 24 and 26 are pressed into contact with each other.
The base strips 17 and 19 can, if necessary, be co-extruded of a
stiffer material so that a certain amount of pressure can be
exerted on the compressible sealing members 24 and 26 when the
zipper profiles 20 and 22 are interlocked. More specifically, the
base strip can be made of a first material having a first modulus
of elasticity, while the sealing structure is made of a second
material having a second modulus of elasticity less than the first
modulus of elasticity.
[0037] The end result is that the internal volume of the bag can be
sealed even though the zipper is partly open in the area of the
slider plow when the slider 14 is in the zipper-closed park
position shown in FIG. 5. In FIG. 5 the bag to which the zipper is
attached is indicated by reference numeral 10, while a slider end
stop is indicated by reference numeral 34. The end stop 34 may be
formed by stomping the ends of the zipper profiles together in a
well-known manner. Optionally, the end of the sealing members may
also be stomped together during end stop formation.
[0038] In the embodiment depicted in FIG. 2, a watertight seal was
formed using two sealing members, each sealing member being joined
to or integrally formed with a respective zipper part.
Alternatively, only one sealing member could be used. FIG. 7 shows
such an embodiment. In this case, the zipper part 16 comprises a
base strip 17 and a closure member 20 having a male profile, while
the zipper part 18 comprises a base strip 19, a closure member 22
having a female profile, and a solitary sealing member 26 in the
form of a hollow tube integrally formed with the base strip 19. The
hollow tube must have a lateral dimension sufficient that the outer
periphery of the sealing member 26 bears against the opposing base
strip 17 when the zipper is closed, as shown in FIG. 7. It should
also be pointed out that the base strips may be designed so that
the overall width of the zipper decreases at a point below the
elevation of the zipper profiles. The shoulders of the base strips
above the zipper narrowing will help resist pull off of the
slider.
[0039] In a variation of the embodiment depicted in FIG. 7, FIG. 8
shows that a seat 40 may be integrally formed with the base strip
17. The seat 40 (which is not compressible or partially collapsible
in the sense those terms are used herein) can be provided with a
surface having a concave profile designed to interface with the
outer periphery of the hollow sealing member 26. The result is that
the area of contact between the sealing member and the opposing
zipper part can be thereby increased to enhance the sealing
effect.
[0040] Although the hollow sealing members 24 and 26 may be made of
the same material used to make the zipper profiles 20 and 22,
alternatively the hollow sealing members may be made by coextruding
a material having greater elasticity, e.g., a soft plastomer.
Plastomers have properties that are generally intermediate those of
thermoplastic materials and elastomeric materials. A typical
plastomer is an elastomeric polymer made of polypropylene and
ethylene-propylene diene rubber.
[0041] In accordance with another embodiment of the invention, a
hollow sealing member 26 may interface with a second compressible
or partially collapsible sealing member 38 that is not a hollow
member. The second sealing member 38 may be made by coextruding a
soft plastomer having a solid profile instead of a hollow profile.
Alternatively, the second sealing member 38 may comprise a soft
closed-cell foam. A foam sealing element could be applied in a
secondary process.
[0042] Taking the idea of using a compressible/collapsible sealing
member that is not a hollow member one step further, both sealing
members could comprise such structures, i.e., plastomeric solid
bodies or closed-cell foam structures. FIG. 10 shows an embodiment
with two such sealing members 38 and 38'. The plastomer or foam
elements will compress or at least partially collapse when pressed
together by the distal portions or panels 30 and 32 (see FIG. 2) of
the slider side walls, thus forming a watertight seal.
[0043] In accordance with a further alternative shown in FIG. 11,
the zipper may be fabricated with a plastomeric or foam sealing
member 38 on one side and a rib 36, made, e.g., of the same
material as the zipper profiles, on the other side of the zipper.
Although a rib 36 having a V-shaped profile is shown in FIG. 11,
the rib may be truncated or curved at its apex. The rib 36 is
situated in line with and directly opposite to the sealing member
38 and is designed to form an indentation 40 in the plastomeric or
foam material when the rib 36 and sealing member 38 are pressed
together by the slider. The watertight seal is formed by the
interface of the apex of the rib 36 with the indentation 40 in the
sealing member 38.
[0044] In accordance with other embodiments of the invention, the
various watertight seals described above can also be used with a
slider-operated string zipper. A string zipper typically does not
have zipper flange extensions for attaching the bag making film.
Instead the bag making film is joined to the outsides of the zipper
base strips at the elevation of the zipper profiles. FIG. 12 shows
the example of a string zipper joined, e.g., by conduction heat
seals, to the top portions of respective walls 6 and 8 of the bag.
The slider is not shown. The respective zipper parts have the same
construction and functionality as the embodiment shown in FIG. 6
except that the zipper does not have flange extensions extending
below the sealing members 24 and 26.
[0045] An alternative slider/string zipper assembly is shown in
FIG. 13. In this case, the slider 14 is provided with a pair of
ribs 46 and 48 that press the sealing members 36 and 38 together.
Again the bottom edges of the slider side walls may be provided
with retaining ledges 50 and 52 at the closing end of the slider
for further increasing the slider pull-off resistance.
[0046] While the invention has been described with reference to
various embodiments, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements 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.
[0047] As used in the claims, the verb "joined" means fused,
bonded, sealed, adhered, fastened, 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, insertion of a rivet, or other
substantially equivalent means.
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