Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CLOSURE DEVICE FOR A RECLOSABLE POUCH
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to closures for reclosable pouches, and more
particularly, to such closures that include two closure mechanisms comprised
of male and
female closure elements.
2. Description of the Background of the Invention
A thermoplastic bag for the storage of items typically includes a closure
mechanism
conlprising multiple profiles disposed on opposed inner surfaces of bag walls.
In a specific
example, two sets of profiles are disposed on the bag walls wherein each set
includes a male
and a female closure element.
Ausnit U.S. Patent No. 3,656,147 discloses a plastic bag having male and
female
resealable interlocking elenients integrally attached thereto for selectively
opening and
closing an end of the bag. The bag further includes a pair of stiffener ribs
formed integrally
with the bag and disposed below the resealable elements to provide increased
rigidity along
an open end of the bag to prevent inadvertent separation of the elements.
Johnson U.S. Patent No. 6,138,329 discloses a reclosable bag having an
assembly that
includes first and secoiid male arrow-shaped profiles extending
perpendicularly from a first
base. The assenibly furtlier includes first and second female U-shaped members
extending
perpendicularly from a second base to engage the first and second male
profiles, respectively.
Each of the male arrow-shaped profiles includes two prongs extending therefrom
that engage
with a female profile. The prongs of the second male profile are longer than
the prongs of the
first male profile to increase the opening force of the second male profile
when interlocked
with a respective female profile.
Malin U.S. Patent No. 6,167,597 discloses a zipper strip for a reclosable
package,
wherein the zipper strip includes a male and a female profile. There are at
least two male
interlocking members that extend from a base toward the opposite female
interlocking
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members, = .
wherein each male member has an asymmetrical arroav shape so that the zipper
is =
easier to open from one side than the other. One or both of the profiles
includes at least one
high compression member that extends from a base thereof to touch a base of
the opposite
profile to allow the profiles to be sealed without crushing or distorting the
, interlocking
members.
SUMMARY OF THE INVENTION
According. to one aspect of the present invention, a reclosable pouch
comprises a body
portion having first and second opposing bag walls, wherein each bag wall h'as
an internal
side. First and second closure mechanisms are disposed on the internal sides
of the first and
second bag walls. The closure mechanisms are parallel and spaced betwem about
0.15 inch
.(3.81 mm) and 0.25 inch (6.35 mm) apart.
According to another aspect of the present invention, a reclosable pouch
comprises a
body portion having first and second opposing bag walls, wherein each bag wall
has an
,
internal side. First and second closure mechanisms are disposed on the
internal sides of the
first and second bag walls. The first closure mechanism provides a clicking
feel during
opening or closing of the first closure mechanism and further provides a first
overall
resistance against opening forces and the second closure mechanism provides a
second
overall resistance against opening forces wherein the second overall
resistance is greater than
the first overall resistance.
According to one aspect of the present invention, a reclosable pouch comprises
a body
portion having first and second bag walls. A first closure mechanism comprises
a first male
closure element and a first female closure element, wherein the fiust female
closure element
has first and second spaced legs. The fnst male and first female closure
elements are
disposed on opposing sides of the first and second bag walls. A second closure
mechanism comprises a second male closure element and a second female closure
element, wherein the
second female closure element has third and fourth spaced legs. The second
male and second
female closure elements are disposed on opposing sides of the first and second
bag walls.
The first male closure element includes two hook portions extending from an
end thereof to
engage the legs of the first female closure element and the second male
closure element
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includes only one hook portion extending from an end thereof to engage one of
the legs of the
second female closure element.
In a further embodiment of the present invention, a zipper tape comprises a
first
zipper tape portion and a second zipper tape portion. The first zipper tape
portion includes a
first inner surface and the second zipper tape portion includes a second inner
surface. A first
closure mechanism comprises a first male closure element and a first female
closure element,
wherein the first female closure element has first and second spaced legs. The
first male and
first female closing elements are disposed on opposing sides of first and
second inner
surfaces. A second closure mechanism comprises a second male closure element
and a
second female closure element, wherein the second female closure element has
third and
fourth spaced legs. The second male and second female closure elements are
disposed on
opposing sides of the first and second inner surfaces. Further, the first male
closure element
includes two hook portions extending from an end thereof to engage the legs of
the first
female closure element and the second male closure element includes only one
hook portion
extending from an end thereof to engage one of the legs of the second female
closure
element.
Other aspects and advantages of the present invention will become apparent
upon
consideration of the following detailed description and the attached drawings,
in which like
elements are assigned like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a reclosable thermoplastic storage bag
incorporating
the present invention;
FIG. 2A is an enlarged, fragmentary, sectional view taken generally along the
lines 2-
2 of FIG. 1;
FIGS. 2B, 3, and 4 are views similar to FIG. 2A illustrating alternative
embodiments
of the present invention;
FIGS. 4A-4D are views also similar to FIG. 2A illustrating further alternative
embodiments of the present invention;
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FIG. 5 is a view similar to FIG. 2A illustrating an alternative embodiment of
the
present invention;
FIG. 5A is a view similar to FIG. 5 illustrating an alternative embodiment of
the
present invention;
FIG. 5B is an enlarged fragmentary view of FIG. 5;
FIG. 6 is an isometric view of an apparatus for producing bags incorporating
the
present invention;
FIG. 7 is an enlarged, fragmentary isometric view of the apparatus of FIG. 6;
FIG. 8 is an enlarged end elevational view of the apparatus of FIGS. 6 and 7;
FIG. 9 is a diagrammatic isometric view of an extrusion apparatus for
extruding
zipper tape incorporating the present invention; and
FIG. 10 is an enlarged, elevational view of a zipper tape incorporating the
present
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1, a reclosable pouch in the form of a thermoplastic storage
bag 20
comprises first and second body portions 22, 24 joined to one another to form
first and
second bag walls 26, 28. The first and second bag walls 26, 28 are joined at
first and second
side portions 30, 32, respectively, and at a bottom portion 34. An opening 35
is disposed at a
top portion 36 of the bag 20. First and second closure mechanisms 38a, 38b and
two lips 40
are also disposed at the top portion 36 of the bag 20. The first closure
mechanism 38a is
disposed between the second closure mechanism 38b and an upper edge 42 of the
top portion
36.
Referring to FIG. 2B, male and female closure elements or portions 44a, 44b of
the
closure mechanism 38a are disposed on opposing internal sides or surfaces 46,
48 of the first
and second body portions 22, 24, respectively. In addition, in the embodiment
of FIG. 2B,
male and female elements or portions 50a, 50b of the closure mechanism 38b are
disposed on
the internal sides or surfaces 48, 46, respectively. Preferably, although not
necessarily, the
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closure mechanism 38a is parallel to the closure mechanism 38b and the two are
spaced from
one another by a distance that is sufficiently small to create the perception
that mechanisms
act as a single closure. In addition, the mechanisms 38a, 38b are preferably
disposed
sufficiently far apart such that a user's fmgers and/or thumb are guided
during the closing
operation. Typically, these results are accomplished by spacing the mechanisms
38a, '38b
between about 0.1 inch (2.54 mm) and 0.3 inch (7.62 mm) apart, and, more
preferably,
between about 0.15 inch (3.81 mm) and about 0.25 inch (6.35 mm) 'apart and
most preferably
about 0.20 inch (5.08 mm) apart, although a different spacing may instead be
used.
Preferably, the closure elements or portions 44, 50 have a cross sectional
shape and/or
may be formed in accordance with the teachings of Geiger, et al. U. S. Patent
No. 4,755, 248,
Zieke et al., U. S. Patent No. 4,741,789, and/or Porchia- et al., U. S. Patent
No. 5,012,561,
owned by the assignee of the present application. Also preferably, the first
closure
mechanism 38a exhibits a first closure characteristic and the second closure
mechanism 38b
exhibits a second closure characteristic different than the first closure
characteristic. For
example, either or both of the first and second closure mechanisms 38 may
exhibit a
relatively low level of resistance to bag opening forces but provide a high
level of
deformation so as to exhibit a clicking feel and/or sound when the bag is
opened or closed.
In addition, either or both of the first and second closure mechanisms 38 may
exhibit a low
level of deformation but provide a relatively high overall resistance to bag
opening forces.
Either or both of the male closure elements 44a, 50a may be symmetric or
asymmetric about
a longitudinal centerline thereof and either or both of the female closure
elements 44b, 50b
may be symmetric or asymmetric about a longitudinal centerline thereof. Thus,
for example,
either or both of the first and second closure mechanisms 38 may have an
asymmetric
configuration so that the closure mechanism 38 exhibits a first resistance to
opening forces
exerted on one side of the mechanism 38 and further exhibits a second,
different resistance to
opening forces exerted on another side of the mechanism 38.
In a specific embodiment, the fust closure mechanism 38a exhibits a high
degree of
deformation so as to develop a clicking feel when the bag is opened or closed.
Preferably,
the first closure mechanism 38a is produced in accordance with the teachings
of Dais et al.,
U. S. Patent No. 5,140,727, owned by the assignee of the present application.
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i =
i =
. - = i . =
In addition, the second closure mechanism 38b provides a relatively high
overall resistance to , =
opening forces. In addition, each closure mechanism 38a and 38b exhibits a
first resistance
to opening forces exerted from inside the bag (i.e., on the side between the
bottom portion 34
of the bag and the closure mechanisms 38) and a second, lower resistance to
opening forces
exerted from the opposite side of the closure mechanisms 38 (i.e., on the side
between the
upper edge 42 and the closure mechanisms 38). This differential opening force
characteristic
is accomplished by asymmetrically configuring the male closure elements 44a
and 50a and/or
the female closure elements 44b and 50b as noted above. In the preferred
embodiment, each
of the closure mechanisms 38a, 38b exhibits substantially the same first
resistance to opening
forces exerted on the side between the upper edge 42 and the closure
mechanisms 38. In
~. .= =
addition, each of the closure mechanisms 38a, 38b exhibits substantially the
same second
resistance to opening forces originating between the bottom portion 34 of the
bag and the
closure mechanisms 38. The second resistance is greater than the first
resistance. It should
be noted that the first closure mechanism 38a may provide the same or
different resistance to
opening forces as compared with the resistance provided by the second closure
mechanism
38b with respect to forces originating from inside the bag and/or from the
opposite side of the
closure mechanism 38.
In addition, if desired, both of the closure mechanisms 38a and 38b or just
the closure
mechanism 38b may exhibit a high degree of deformation so as to develop a
clicking feel
when the bag is opened or closed. Still further, more than two closure
mechanisms 38 may
be provided wherein the closure mechanisms 38 have differing or the same
closure
characteristic(s) and the closure mechanisms act together as a single unit to
allow the user to
open and close the bag.
If desired, and as seen in FIGS. 2A, 3, and 4, one or more strips 60 could be
provided
between the closure mechanisms 38a, 38b (optionally out of contact, i.e., not.
touching, the
adjacent closure elements) on either or both of the internal sides or surfaces
46, 48. The
strips 60 may be colored or uncolored and may lend stiffness to the structure.
According to a fust embodiment, the male closure element 44a, the female
closure element 50b and an
optional strip 60a disposed between the elements 44a and 50b are colored pink,
whereas the
female closure element 44b and the male closure element 50a are colored blue.
An optional
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further strip 60b may be disposed on the surface 48 between the closure
elements 44b and
50a and may be colored blue. The size and shape of the strips 60 may be
selected as desired
to obtain a desired feel and/or stiffness.
As a further alternative, each of the optional strips 60 may simply comprise a
thin
colored coating, such as very thin layer of colored thermoplastic, a colored
epoxy, a layer of
paint, etc...
FIG. 3 illustrates a further embodiment wherein like reference numbers denote
structures common to the various embodiments. As seen in FIG. 3, the male
closure elements
44a and 50a are disposed on the internal side or surface 46 and the female
closure elements
44b and 50b are disposed on the internal side or surface 48. In this
embodiment, a single
strip 60a is provided between the male elements 44a and 50a on the internal
side or surface
46. Additionally or alternatively, a strip 60b (seen in phantom in FIG. 3) may
be provided
between the female closure elements 44b and 50 on the internal side or surface
48. One or
more additional strips may be provided on either or both surfaces 46, 48. If
desired, other
structures might be included with the closure mechanisms and the strips. For
example, one or
more guide ribs (not shown) could be provided to further assist in guiding of
the user's
fingers. Further, any or all of the strips 60 and/or other structures may be
disposed between
the closure mechanisms 38a, 38b or may be disposed outside of (i.e., above or
below as seen
in FIG. 1) the mechanisms 38a, 38b.
In any of the embodiments disclosed herein, one or more gripping ribs 74 may
be
disposed on the internal surfaces 46, 48 of the bag 20 between the closure
mechanisms 38a
and 38b and the top portion 36 of the bag 20, wherein the gripping ribs 74 are
integrally
extruded with the walls of the bag. Any number of gripping ribs 74 can be
used, although
space is necessary between adjacent ribs in order to facilitate a gripping
action with a user's
fingers. In a preferred embodiment, about six or seven gripping ribs 74 are
disposed on each
lip 40 of the bag.
As seen in FIG. 3, each male closure element 44a, 50a comprises an arrow-
shaped
engagement member 80, 82, respectively, and a base member 84, 86,
respectively. Each
female closure element 44b, 50b comprises a C-shaped profile member 90, 92,
respectively,
joined to base members 94, 96, respectively. The base members 84, 86 are only
slightly
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wider than the engagement members 80, 82 and the base members 94, 96 are only
slightly
wider than the side-to-side extent (as seen in FIG. 2A) of the C-shaped
profile members 90
and 92. The same is true of the embodiment of FIG. 2A. In both of these
embodiments
relatively little resin is required to form the closure mechanisms 38. In
fact, it is believed that
only a minimal increase in resin is needed to produce the closure elements 38
compared to a
standard bag design utilizing a single closure mechanism, and yet a closure is
obtained that
has a wide-track feel and superior resistance to inadvertent opening.
FIG. 4 illustrates yet another embodiment of the present invention wherein the
closure
mechanisms 38a, 38b are replaced by closure mechanisms 138a, 138b. The
mechanism 138a
includes male and female closure elements 144a, 144b and the mechanism 138b
includes
male and female closure elements 150a, 150b. The mechanisms 138a, 138b are
identical, and
hence, only the closure mechanism 138a will be discussed in detail. The male
closure
element 144a of the closure mechanism 138a comprises a base 154 integral with
flanking side
members 156 and 158 and an arrow-shaped engagement member 160 that extends
from the
base 154. A female closure element 144b comprises a base 162 with a C-shaped
profile
member 164 extending therefrom, wherein the female closure element 144b is
adapted to
receive the male closure element 144a when pressure is exerted on the closure
elements by a
user's finger(s) during closing of the bag. The side members 156 and 158 are
of a sufficient
size and proximity to the engagement member 160 such that the side members 156
and 158
move together with the member 160 when the members 160 and 164 are engaged and
disengaged. The side members 156 and 158 also have a height that is less than
the height of
the engagement member 160, and the members 156 and 158 extend beyond tips 168
of the
female profile member 164 when the engagement member 160 is engaged with the
female
profile member 164. Thus, at such time, the tips 168 of the female profile
member 164 reside
between the side members 156 and 158 and the male engagement member 160.
As in the previous embodiments, the male closure elements 144a, 150a may be
disposed on the same bag wall or on different bag walls, as may the female
closure elements
144b, 150b.
As should be evident by a comparison of FIGS. 3 and 4, the base members 84,
86, 94,
and 96 of FIG. 3 are replaced by elongate members 180, 182, 184, 186,
respectively, and
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hence, more resin is required to produce the closure mechanisms 138a, 138b as
compared to
the closure mechanisms 38a, 38b. However, the elongate members 180-186 further
promote
guiding of the user's fingers and thumb during closing of the bag. One or more
strips 187
identical or similar to the strip(s) 60 may be provided as . noted in
connection with the
previous embodiments.
If desired, in any of the embodiments described herein, adjacent closure
elements may
be interconnected by a web of film. Thus, for example, FIG. 4A illustrates
modifications to
the embodiment of FIG. 2A wherein the female closure element 44b is
interconnected to the
male closure element 50a by a web 188a that is integrally or separately
extruded with the
elements 44b and 50a. In addition, the male closure element 44a may be
interconnected to
the female closure element 50b by a web 188b that is integrally or separately
extruded with
the elements 44a, 50b. FIG. 4B illustrates the same features in connection
with the
embodiment of FIG. 3. That is, in FIG. 4B, the female closure elements 44b and
50b are
interconnected by a web 188c whereas the male closure elements 44a and 50a are
interconnected by a web 188d.
Optionally, in FIGS. 4A and 4B, the closure elements 44, 50 and/or the webs
188a-
188d may have the same or different visual characteristic(s). Suitable visual
characteristics
include visual material characteristics such as transparency, translucency or
opaqueness,
coloring of transparent, translucent, or opaque material by dye or other
suitable colorants,
printing or embossing of indicia, or the like. For example, portions or the
entirety of the web
188a may have a first visual characteristic, such as pink coloring, and
portions or the entirety
of the web 188b may have a second, different visual characteristic, such as
blue coloring. In
addition, and taking the embodiment of FIG. 4A as an example, portions or the
entirety of
one or both of the closure elements 44a and 50b may have the same or a
different visual
characteristic as the web 188b or 188a. The same may be true of the closure
elements 44b,
50a relative to the visual characteristic of the web 188a or 188b. When the
respective closure
elements 44a, 44b and 50a, 50b are mated, the first and second visual
characteristics, such as
the pink and blue colorings, respectively (if used), blend together to form a
single visual
characteristic, such as purple coloring, indicating full closure thereof. If
desired, central
portions of the webs 188a, 188b intermediate the closure elements 44b, 50a and
44a, 50b,
respectively, (or corresponding intermediate portions of the webs 188c, 188d)
may be
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thickened so that such portions come into contact with one another when the
closure elements
44, 50 are occluded. This can enhance the color change effect and provide a
tactile
confirmation of closure. In addition to the foregoing, any of the webs may
include any tactile
characteristic including, but not limited to, embossing, a thicker feeling, or
a cushioned
feeling. Alternatively, intermittent portions along the lengths of the closure
elements 44, 50
and/or webs 188a-188d may have any visual or tactile characteristic. For
example, referring
to the embodiment of FIG. 4B, the web 188c may have a first alternating
pattern formed by
separate portions along the length thereof (i.e., from side-to-side of the bag
20) that have a
visual characteristic comprising pink coloring and remainder portions of the
web 188c
intermediate the pink portions that have a different visual characteristic,
such as translucent
uncolored (i.e., clear) portions. In addition, the web 188d may have a second
alternating
pattern of pink and clear (or another visual characteristic) portions that are
disposed at least
partially out of phase with respect to the first alternating pink and clear
(or other visual
characteristic) pattern of the web 188c. Preferably, although not necessarily,
the first
alternating pattern is a regular pattern (i.e., the pink portions are all of
substantially the same
first length, and the remaining clear portions are all of substantially the
same second length,
where the first and second lengths are equal or unequal) and the second
alternating pattern is
identical to the first alternating pattern, but is displaced 180 degrees with
respect thereto.
When the closure elements 44a, 44b and 50a, 50b are correctly mated, the
alternating pink
and clear (or other visual characteristic) portions of the webs 188c, 188d
come together to
form a substantially full line of substantially uniform color (or other visual
characteristic) to
indicate closure thereof. As should be evident from the foregoing, any portion
of any of the
webs 188 and/or closure elements 44, 50 may be any visual characteristic,
including different
colors, clear, translucent, or opaque material, or printed indicia, and
opposite webs and/or
closure elements 44, 50 may have the same visual characteristic(s) or
different visual
characteristic(s) to assist in providing a visual indication of at least
partial occlusion of the
closure elements 44, 50.
As seen in FIGS. 4C and 4D, webs 288a-288d may also be separately extruded
onto
the body portions 22, 24 intermediate and separate from the closure elements
44a, 44b, 50a,
and 50b. Any of the embodiments described above in connection with FIGS. 4A
and 4B are
possible for the configurations shown in FIGS. 4C and 4D. The webs 288a-288d
may also be
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made from any material including, but not limited to, a thermoplastic material
or a foam
material. For example, in FIG. 4C, the web 288a may have a first visual
characteristic such
as a translucent blue coloring and the web 288b may have a second visual
characteristic such
as a translucent yellow coloring, such that when the respective closure
elements 44a, 44b and
50a, 50b are mated, the blue and yellow colors blend together to form a visual
characteristic
such as a green color that indicates full closure of the closure elements 44a,
44b and 50a, 50b.
Further, in FIG. 4D, intermittent portions of the web 288c may have any visual
"characteristic,
such as white coloring, to form a third regular or irregular alternating
pattern of alternating
white and clear portions and intermittent portions of the web 288d may have a
visual
characteristic including white coloring to form a fourth regular or irregular
pattern of
alternating white and clear portions wherein the third pattern is preferably
(although not
necessarily) identical to the fourth pattern, but displaced 180 degrees with
respect thereto. As
in the previous embodiment, when the closure elements 44a, 44b and 50a, 50b
are mated, the
alternating portions of the web portions 288c, 288d line up to from a full
line of a visual
characteristic (in this embodiment, a continuous white line) to indicate
closure thereof. Also
as in the previous embodiment, the thicknesses of the webs 288c, 288d may be
such that at
least portions of the webs 288c, 288d contact one another to enhance color
change when the
closure elements 44, 50 are properly mated.
As mentioned above, any of the webs 188a-188d or 288a-288d may have a visual
characteristic including printed indicia thereon. For example, a first web may
comprise a
clear material with printed indicia including, for example, the word "closed"
printed on an
inner surface thereof and a second, opposing web may have a visual
characteristic comprising
a clear material. When the respective closure mechanisms are mated, the word
"closed"
appears through the second web to indicate full closure thereof.
Alternatively, a word such as
"closed" may be printed on inner surfaces of first and second clear webs at
laterally spaced
locations such that when the respective closure mechanisms are properly mated,
the word
"closed" appears clearly through the first and second webs at the laterally
spaced locations to
indicate full closure thereof. Printed indicia are not limited to words, but
can also include any
number, patterns, designs, or the like.
FIG. 5 illustrates yet another embodiment of the present invention, wherein
the
closure mechanisms 38a, 38b are replaced by first and second closure
mechanisms 238a,
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238b, respectively. The first closure mechanism 238a comprises a first male
closure element
244a and a first female closure element 244b. Both the first male and female
closure
elements 244a, 244b are substantially symmetric about a centerline 246, as may
be seen in
FIG. 5. The first male closure element 244a includes an engagement member 250
having two
hook portions 251a, 251b that extend from a base 248a. The first female
closure element
244b includes a base 248b with a first spaced leg 252 and a second spaced leg
254 extending
therefrom. The first female closure element 244b is adapted to receive the
first male closure
element 244a when pressure is exerted on the closure elements by a user's
finger(s) during
closing of the bag. In a preferred embodiment, the second closure mechanism
238b
comprises a second male closure element 256a and a second female closure
element 256b. In
this embodiment, the first female closure element 244b of the first closure
mechanism 238a is
substantially or completely identical to the second female closure element
256b of the second
closure mechanism 238b. As such, the second female closure element 256b
includes a base
258b with a third spaced leg 260 and a fourth spaced leg 262 extending
therefrom. The
second female closure element 256b is also adapted to receive the second male
closure
element 256a when pressure is exerted on the closure elements by a user's
finger(s) during=
closing of the bag. The second male closure element 256a includes an
engagement member
264 comprising only one hook portion 265 that extends from a base 258a. As
should be
evident, the second male closure element 256a is substantially asymmetric
about a
longitudinal centerline 266. As may be seen in FIG. 5, the first female
closure element 244b
of the first closure mechanism 238a is adjacent the second male closure
element 256a of the
second closure mechanism 238b on the first bag wall 26. The first female
closure element
244b is also disposed closer to an upper edge 42 of the pouch on the first bag
wall 26 than the
second male closure element 256a. Additionally, the first male closure element
244a of the
first closure mechanism 238a is adjacent the second female closure element
256b of the
second closure mechanism 238b on the second bag wall 28. The first male
closure element
244a is disposed closer to an upper edge 42 of the pouch on the second bag
wall 28 than the
second female closure element 256b. In another embodiment depicted in FIG. 5A,
the first
female closure element 244b of the first closure mechanism 238a is adjacent
the second
female closure element 256b of the second closure mechanism 238b on the first
bag wal126,
while the first male closure element 244a of the first closure mechanism 238a
is adjacent the
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second male closure element 256a of the second closure mechanism 238b on the
second bag
wall 28.
In a preferred embodiment, the first closure mechanism 238a is opened by
disengaging its respective closure elements 244a, 244b with a first opening
force and the
second closure mechanism 238b is opened by disengaging its respective closure
elements
256a, 256b with a second opening force. Both the first and second opening
forces comprise
respective internal and external opening forces. In one embodiment, the first
male closure
element 244a disengages from the first female closure element 244b with a
first external
opening force and the second male closure element 256a disengages from the
second female
closure element 256b with a second external opening force. The first and
second external
forces are substantially exerted from a side of the bag nearer the upper edge
42, as opposed to
internal bursting forces that act on the closure mechanisms 238a, 238b from
within the pouch.
In a preferred embodiment, the first closure mechanism 238a primarily
determines the
external opening force of the bag whereby the first external opening force is
larger than the
second external opening force. This difference in forces results from the fact
that first male
closure element 244a of the first closure mechanism 238a has the hook portion
251a whereas
the second male closure element 244a lacks a hook portion in a corresponding
location (i.e.,
toward the upper edge 42). The elimination of an extra portion on the opposing
side (toward
the upper edge 42) of the engagement member 264 allows for the second female
closure
element 256b to flex less around the second male closure element 256a during
opening of the
bag 20. The result of the reduced flexing in the second closure mechanism 238b
is a lower
external opening force than exhibited by the first closure mechanism 238a.
Additionally, as
seen in FIG. 513, the second male closure element 256a has a thickness A at a
root portion
268 of the engagement member 264 and a thickness B at the widest part of the
hook portion
265. In a preferred embodiment, the thicknesses A and B are substantially
equal.
Alternatively, the thickness B can be increased, thereby increasing the
external opening force
developed by the closure mechanism 238b.
Like the other embodiments, the embodiment illustrated in FIG. 5 includes two
closure mechanisms wherein the first closure mechanism 238a exhibits a first
closure
characteristic and the second closure mechanism 238b exhibits a second closure
characteristic. Preferably, the second closure characteristic comprises a
first resistance to an
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external opening force applied to a first side of the second closure mechanism
238b and a
second resistance to an internal opening force applied to a second side of the
second closure
mechanism 238b. As mentioned above, the second closure mechanism 238b
preferably has a
very low external opening force because the second male closure element 256a
includes only
one hook portion 265 that is directed toward the inside of the bag 20.
Therefore, the second
closure mechanism 238b is more apt to withstand internal bursting forces as
opposed to
external opening forces. The first closure mechanism 238a, in effect, controls
the external
opening force of the bag 20, whereas the second closure mechanism 238b
primarily
determines the resistance to burst forces exerted from within the bag 20.
In a further embodiment of the present invention, the first closure mechanism
238a
exhibits a clicking feel and/or sound when the bag is opened or closed. Such a
clicking feel
is created by providing a high level of deformation within the first closure
mechanism 238a.
The first male and female closure elements 244a, 244b may be similar in
structure to the
embodiments characterized in FIGS. 2A and 2B, which also provide for a high
level of
deformation.
As should be evident, the first male closure element 244a engages with the
first
female closure element 244b with a first closing force and the second male
closure element
256a engages with the second female closure element 256b with a second closing
force. In
one embodiment, the first closing force is greater than the second closing
force. In another
embodiment, the second closing force is greater than the first closing force.
Still further,
other embodiments have first and second closing forces that are approximately
equal. For
example, for a zipper at a 64 mil thickness (1.6 nim) an average closing force
for the first
closure mechanism 238a was found to be 0.151b. (0.07 kg.), an average closing
force for the
second closure element 238b was found to be 0.051b. (0.02 kg.), and the
overall closing force
for the combined mechanisms 238a, 238b was found to be 0.20 lb. (0.09 kg.).
When the
zipper thickness was increased to 75 mils (1.9 mm) an average closing force
for the first
closure mechanism 238a was found to be 0.181b. (0.08 kg.), an average closing
force for the
second closure element 238b was found to be 0.061b. (0.03 kg.), and the
overall closing force
for the combined mechanisms 238a, 238b was found to be 0.241b. (0.11 kg.).
Preferably, the
overall closing force of the first and second closure mechanisms 238a, 238b is
within the
range of about 0.10 - 0.45 lb. (0.05 to 0.20 kg.), and more preferably in the
range of about
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0.15 to 0.35 lb. (0.07 to 0.16 kg.), and most preferably in the range of about
0.20 to about
0.30 lb. (0.09 to 0.14 kg.). An overall closing force within the most
preferred range allows a
dual closure mechanism bag to have a similar overall closing force to those
found in
conventional single closure mechanism bags. The present embodiment allows for
a
significantly stronger dual closure mechanism bag while also allowing the user
to "feel" as if
he were using a single closure mechanism bag with a wide-track feel.
Reclosable thermoplastic storage bags as described herein can be produced by
any
suitable bag-making process, such as a cast post applied process, a cast
integral process, a
blown process or any other process known in the art. It should be noted that
the extrusion
die(s) used to form the closure mechanisms and strip(s) must include a
suitable number of
profile plates to form such structures. In addition, an air nozzle may be
provided in
association with each female closure element that blows air into the opening
of each C-
shaped female profile member to open the member as it is being extruded. In
addition, one or
more cooling water jets may be provided to cool the male and female closure
elements after
they are extruded.
If desired, an alternative post applied process can be used to produce any of
the bags
disclosed herein, such as seen in FIGS. 6 and 7. Referring to such FIGS., the
alternative post
applied process utilizes an extrusion apparatus including a first extrusion
slot die 300, a
temperature-controlled driven casting rol1302, edge pinning devices or
apparatus 304a, 304b,
an air knife 306, second and third extrusion dies 308a, 308b (that are
diagrammatically shown
and which, together with the die 300, form the extrusion apparatus) and
blowing apparatus
310a, 310b. The extrusion die 300 receives molten thermoplastic from an
extruder (not
shown) and deposits the thermoplastic in sheet form as a web 312 onto the
casting roll 302.
The extrusion die 300 includes a slot opening (not shown) that forms thickened
areas 314,
316 at outside edge portions 318a, 318b of the resulting web 312 and a
relatively thinner
portion 320 intermediate the thickened areas 314, 316. The edge portions 318a,
318b are
pinned to the casting roll 302 by the edge pinning devices 304a, 304b,
respectively. The web
312 is then pinned across the entire width thereof (i.e., as a whole) to the
casting roll 302 by
the air knife 306.
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After the web 312 is pinned to the casting roll 302, the male and female
closure
elements 44, 50 or 144, 150 are formed on the web 100. Preferably, the
extrusion dies 308a,
308b receive molten thermoplastic from separate extruders and extrude the male
and female
closure elements 44, 50 or 144, 150 onto the thickened areas 314, 316.
Alternatively, the
separate extrusion dies 308a, 308b may be replaced by a single extrusion die
having two
outlets at which the male and female closure elements 44, 50 or 144, 150 are
simultaneously
extruded onto the thickened areas 314, 316. As a still further alternative,
each extrusion die
308a, 308b may be replaced by two or more extrusion dies that individually and
separately
extrude the closure elements 44, 50 or 144, 150 and the strip(s) 60, 187. In
any event, as seen
in FIG. 8, the angle of a face 322 of each die 308 is at least initially
disposed substantially
parallel to a horizontal radial line 324 extending from the center of the
casting roll 302. The
position of the die 308 (or each die 308a, 308b individually if separate dies
are used) may
then be adjusted by moving the die left, right, up, or down (all as seen in
FIG. 8) or the die
may be tipped (i.e., angularly displaced) to adjust the angle of the die face
322 to obtain
desirable results. The closure elements 44, 50 or 144, 150 formed by the
die(s) 308 may exit
the die(s) 308 at a point coincident with a vertical tangent line 326 (FIG. 8)
intersecting the
surface of the casting roll 302 on the side of the casting roll 302 where the
web 312 is first
deposited thereon. Alternatively, the closure elements 44, 50 or 144, 150
formed by the
die(s) 308 may exit the die(s) 308 at a point displaced to the right or left
(as seen in FIG. 8) of
the tangent line 326. If the extrudate exits the die(s) 308 at a point
displaced to the right of
the line 326, some provision must be made at the initiation of production to
attach the
extrudate stream to the casting roll 302. Thereafter, production may commence,
(provided
that the exit of the die(s) 308 is not disposed too far to the right of the
tangent line 326)
whereupon the melt strength of the extrude stream carries the stream into
contact with the roll
302.
Once the molten thermoplastic from the die(s) 308 has been deposited onto the
web
312, coolant is applied to the closure elements 44, 50 or 144, 150 by coolant
apparatus (not
shown) to bring the temperature thereof below the melting point of the
thermoplastic material
forming the closure elements 44, 50 or 144, 150 as quickly as possible.
Preferably, the
coolant comprises water or any other suitable cooling fluid and the coolant is
applied to the
material of the closure elements 44, 50 or 144, 150 only after such material
contacts the
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material of the web 312 so that adhesion thereto is optimized. The web 312 and
the closure
elements 44, 50 or 144, 150 are maintained in contact with the temperature-
controlled casting
roll 302 for a period of time as the roll 302 is rotated so that the web 312
and closure
elements 44, 50 or 144, 150 are further cooled. The casting roll 302 should be
maintained at
a temperature below the melting point of the thermoplastic material(s) forming
the web 312
and the closure elements 44, 50 or 144, 150, typically about 20-80 degrees C.
If desired, any of the closure elements and/or strips and/or other associated
structures
of the above embodiments can be integrally or separately extruded on internal
surfaces of
flanges to form zipper tape that is subsequently post-applied to film in a bag
production
process. For example, as seen in FIG. 9, the zipper tape includes a first
zipper tape portion
400 and a second zipper tape portion 402 that may,be extruded separately by an
extrusion die
404 into a water bath 406. If desired, more than one extrusion die may be
employed for this
purpose. The zipper tape portions 400, 402 extend about pulleys or rollers
408, 410,
respectively, in the water bath 306 and may further extend about additional
pulleys or rollers
412, 414 and 416, 418 out of the water bath 406. The zipper tape portions 400,
402 may
thereafter pass through a dewatering station 420, where the water is removed
therefrom, and
the portions 400, 402 may be joined together (i.e., occluded) by nip rollers
422. The
occluded portions 400, 402 may thereafter be stored on spools or reels or the
occluded
portions may be directly delivered to an in-line bag manufacturing apparatus,
where the
portions 400, 402 are laminated or otherwise secured to bag film.
Referring to FIG. 10, the first zipper tape portion 400 includes a first inner
surface
430 and closure elements 444b and 456a secured to the first inner surface 430.
The second
zipper tape portion 402 includes a second inner surface 432 and closure
elements 444a and
456b secured to the second inner surface 432. The closure elements 444b, 456a,
444a, and
456b may be similar or identical to the closure elements 244b, 256a, 244a, and
256b,
respectively, described above. In some embodiments, the zipper tape may be
relatively
thicker at areas that ultimately form the top of the bag and relatively
thinner at areas where
the zipper tape is to be joined to the film. Also, gripping strips (not shown)
may be formed at
the areas that ultimately form the top of the bag.
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INDUSTRIAL APPLICABILITY
The pouch described herein advantageously allows for dual closure mechanism
pouches to be used that have opening and closing force characteristics similar
to those found
in single closure mechanism pouches. Thus, closing and opening efficiency is
increased and
the expenditure of wasted effort by the user is minimized.
Further, the pouch of the present invention can provide aural and tactile
feedback of
closing and opening of the pouch. Still further, the present pouch can provide
a plurality of
different closure characteristics and can provide greater security against
inadvertent opening
of the pouch. The distance between the closure mechanisms can be varied as
desired, and the
male and female closure elements may be disposed on either wall with or
without strip(s)
therebetween. Other structure(s) may be disposed between or outside of the
closure
mechanisms, as desired.
Numerous modifications will be apparent to those skilled in the art in view of
the
foregoing description. Accordingly, this description is to be construed as
illustrative only and
is presented for the purpose of enabling those skilled in the art to make and
use the invention
and to teach the best mode of carrying out same. The exclusive rights to all
modifications
which come within the scope of the appended claims are reserved.
