Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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APPARATUS FOR MANUFACTURING
FLEXIBLE PACKAGES RAVING SLIDE FASTENERS
AND FOR FILLING THROUGH THE SLIDE FASTENERS
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to the
manufacture of flexible packageS,.such as plastic bags,
and in particular to packages having fastener closure's
employing sliders.
2. Description Of The Related Art
With the recent emphasis in providing consumers
with bulk quantities of various commodities, such as food
products, reclosable packages have become increasingly
popular. One of the most popular means of providing
reclosability is o employ zippers of various types,
particularly zippers which are compatible with flexible
packages of plastic film construction. Manufacturers of
food products and other commodities are concerned with
filling the contents of a flexible package as quickly and
economically as possible. It is important that the
opening provided by the fastener be made as large as
practically possible. Consumers or other end users also
prefer large sized openings for easy extraction of
products from the package interior. Even with large
openings, however; products within the package may
interfere with fas ever operation when product poured or
otherwise dispensed from the package becomes entrained in
the fastener components.
Other improvements to flexible reclosable
packages are being sought. For example, when handling
products comprised of numerous small pieces, such as
shredded cheese or cereal; for example, it is generally
desirable to have the package formed into a pouch which
is open atone end, or along one side, so as to allow
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product to be poured or shaken through the reclosable
opening. It is desirable that the product be allowed to
freely flow past the reclosable opening. Preferably, the
path,taken by the product within the package should be
made as smooth as possible:
Although improvements have been made in the art
of plastic welding and joining, manufacturers of consumer
products employing high speed production techniques are
continually seeking improved package forming methods and
equipment.
SUMMARY OF THE INVENTION
It is an object of the invention to provide
apparatus for forming, filling and sealing of improved,
shrouded and unshrouded flexible packages.
Another object of the invention is to provide
apparatus for making reclosable packages having fastener
sliders which are protected as the package contents are
poured out or otherwise extracted.
A further object of the invention is to provide
apparatus for making a reclosable plastic package having
a slider fastener with improved containment of the slider
in a manner which also optimizes the size of the bag
opening.
A further object of the invention is to provide
apparatus for making a plastic bag having a slider
fastener with an improved end "crush" stop of the
fastener tracks.
These and other objects of the invention are
attained in a horizontal form-fill seal machine for the
in-line manufacturing of food packages with shrouded,
mated fastener tracks and slider closures, that comprises
a supply of web material that extends in a machine
direction that defines a serial succession of package
sidewalls and extends in the machine direction. A supply
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of mated fastener tracks, which include a first track
with a shorter flange mated to a second track with a
longer flange. A folding member which receives web
material. A web drive that transports web material over
folding member in the machine direction, folding web
material into overlying side-by-side portions, one
against the other, to form a continuous succession ofi
i
folded package portions, which extend in the machine
direction and which have pairs of overlying first and!
second package sidewalls that have overlying free edges
with shroud portions at the free edges. A slider member
mateable with mated fastener tracks for movement along
mated fastener tracks in opposite directions to open and
close mated fastener tracks. A slider installation
member that is inserted in the slider member onto mated
fastener tracks. Fastener seal bars.extend in the
machine direction, that seal a portion of each flange of
the fastener tracks to the first sidewall. Side seal
bars extend at an angle to machine direction, and seal
portions of said package sidewalls together to form
respective side seals of the food package. A filler
member filling product into package. Sidewall sealing
means that seal second package sidewall to second track
flange and a shroud sealing member that eals the free
edges of the package sidewalls to form a shroud enclosing
the fastener tracks, to form a completed food package.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. l is a fragmentary front elevational view
of a flexible package according. to principles of the
present invention;
FIG. 2 is a fragmentary cross-sectional view
taken along the line 2-2 of FIG. 1;
FIG. 3 is a fragmentary end view indicated by
line 3-3 of FIG. 1;
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FIG. 4 is fragmentary front elevational view
showing construction of the flexible package;
FIG. 5 is a top plan view of the slider member;
FIG. 6 is a front elevational view thereof;
FIG. 7 is an elevational view from one end
thereof;
FIG. 8 is an elevational view from the other
end thereof;
FIG: 9 is an end view of a fastener track sub-
assembly;
FIG. 10 is a cross-sectional view, in schematic
form, taken along the line l0-10 of FIG. l with the
slider moved to the left;
FIG. 10a is a fragmentary view, of FIG. 10
shown on an enlarged scale;
FIGS. lOb and lOc show alternative seal
constructions;
FLG. 11 is a fragmentary front elevational view
showing contents being poured from the flexible package;
FIG. 12 is a fragmentary front elevational view
showing contents of a prior art package;
FIG.13 is a fragmentary front elevational view
of another flexible package according to principles of
the present invention;
FIG. 14 is a front elevational view of another
flexible package according to principles of the present
invention;
FIG: 15 is a fragmentary elevational view of a
shrouded flexible package constructed according to .
principles of the present invention;
FIG. 16 is a fragmentary cross-sectional view
taken along line l6-l6 of FIG. l5;
FIG. 17 is a fragmentary end view of the
package of FIG. 15;
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FIG. 18 is a fragmentary elevational view of a
further embodiment of a flexible package constructed
according to principles of the present invention;
FIG. 19 is a fragmentary elevational view of
another embodiment of a shrouded flexible package;
FIG. 20 is a cross-sectional view taken along
the line 20-20 of FIG. 15;
FIG: 21 is a cross-sectional view similar to
than of FIG. 20, shown with the schematic depiction o~
tooling to form the flexible package;
FIG. 22 is a fragmentary elevational view of a
further embodiment of a shrouded flexible package;
FIG. 23 is a fragmentary elevational view of an
additional embodiment of a shrouded flexible package;
FIG. 24 is a cross-sectional view similar to
that of FIG. 20 but showing an alternative shroud
construction;
FIG. 25 is a fragmentary elevational view of a
further embodiment of a shrouded flexible package;
FIG. 26 is a perspective view of apparatus for
constructing flexible packages according to principles of
the present invention;
FIG. 27 is a side elevational view thereof;
FIG. 28 is a fragmentary view showing the
plastic web;
FIG. 29 shows the plastic web being folded;
FRGS. 30a, 30b comprise a fragmentary
perspective view of the left-hand portion of FIG. 26;
FIG. 31 is a fragmentary view of the lower
right corner of FIG. 30, taken on an enlarged scale;
FIG. 32 shows an operation performed on the
bottom of the web portions;
FIG. 33 shows a portion thereof taken on an
enlarged scale;
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FIG. 34 shows end stop and slider work stations
of FIG. 26, taken on an enlarged scale;
FIG. 35 i a cross-.sectional view taken along
the line 35-35 of FLG. 30a;
FIG. 36 is a cross-sectional view taken along
the line 36-36 of FIG. 30b;
FIG. 37 shows a vertical sealing work station
portion of FIG: 26;
FIG. 38a is a fragmentary cross-sectional view
taken along the line 38a-38a of FIG. 30b;
FIG. 38b is a view similar to that of FIG. 38a,
but showing a latter stage of operation;
FIG. 39 shows one example of a flexible package
constructed with apparatus according to principles of the
present invention;
FIG. 40 shows a severing work station of FIG.
26, on an enlarged.sCale;
FIG. 41 is a perspective view showing filling
of a flexible package;
FIG. 42 is a side elevational view thereof;
FIG. 43 is a top plan view thereof;
FIGS. 44a-44d show opening and filling
operations;
FIGS. 45a, 45b show final sealing operations
performed on the flexible package;
FIG. 46 is a cross-sectional view taken along
the line 46-46 of FIG. 45b; and
FIG. 47 is a cross-sectional view taken along
the line 47-47 of FIG. 39.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and initially to
FIGS. 1-8, an improved flexible package is generally
indicated at 10. The terms "package" and "bag," are used
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interchangeably and are not intended to refer to any
relative size of the finished item.
Flexible package 10 preferably comprises a
plastic bag having-front and back panels 12, 14 joined
together at the left end by a side seal 20 and at the
right end by a side seal 22. Side seal 20 is preferably
of conventional conduction heat-sealed construction,
having a generally constant width throughout. If
desired, side seal 20 can be employed on both sides of
the flexible package. Panels 12, 14 are further joined
together at their bottom ends by a bottom seal 24 (see
FIG. 10) extending between side seals 20, 22, as is known
in the art. Alternatively, the bottom seal can be
replaced by a fold line with panels 12, 14 being formed
from a continuous sheet of plastic material.
The upper end of flexible package 10 features a
reclosable opening including a slide fastener arrangement
with fastener tracks 26; 28 and a slider 30, all
preferably of polyolefin material. The slider 30 is
slidable along the fastener tracks, causing the fastener
tracks to interlock or mate (as shown in FIG. 2) for
closure of the flexible package and to unmate or separate
to open the flexible package for access to contents iri
the package interior. As will be seen herein, features
associated with the fastener slider arrangement allow an
unprecedented enlarged opening of the flexible package.
The enlarged package opening made possible by the present
invention benefits manufacturers filling the package, as
well as consumers dispensing product from the interior of
the flexible package. In the preferred embodiment shown,
the fastener tracks are also referred to as "zipper"
tracks.
The flexible package according to principles
of the present invention has found immediate commercial
acceptance for use with food products, including
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perishable food products, such as cheese. Accordingly,
it is generally preferred that the flexible package
includes a hermetic seal 36 in the form of a peelable
seal as taught in commonly assigned United States Patent
Nos. 5,014,856; 5,107,658 and 5,050,736, the disclosures
of which are incorporated by'reference as if fully set
forth herein.
As mentioned above, flexible package 10
preferably comprises a bag having panels 12, 14 formed
from plastic sheet material. The sheet material can be of
a single material type, such as polyolefin materials
including polyethylene and polypropylene, but preferably
comprises a laminate assembly of several different
material types, as is known in the art to provide a
barrier to moisture as well as certain gases, such as
oxygen or inert fillers of the types used with food
products. Other types of laminate films, such as those
known in the art to preserve food freshness, may be
employed: Where the contents of the flexible package are
not perishable or where other considerations may dictate,
the panels 12 ,14 can be constructed without regard to
gas or vapor barrier properties. FIGS. 2 and 3 indicate
that it is generally preferred that the fastener tracks
be joined to web-like flanges which, in turn, are joined
to panels 12, l4 as will be described below with
reference to FIG. 10.
Referring now to FIGS. 5-8, fastener slider 30
has a top wall 44, a shorter side wall 46 and a longer
side wall 48, cooperating to define an internal cavity 50
for receiving the fastener tracks 26, 28. As can be seen
by comparing the end views of FIGS. 7 and 8, a first end
54 of the slider defines a cavity which is generally
rectangular. The opposed end 56 (shown in FIG. 8)
defines a cavity which is generally arrowhead or
A-shaped, as indicated by reference numeral 50b,
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conforming to the outline of the interlocked fastener
tracks shown in FIG. 2. When the slider 30 of FIG. 1 is
moved to the right, end 56 is at the leading end of the
slider and the fastener tracks 26, 28 are unlocked, thus
opening the flexible package 10. Conversely, as slider
30 of FIG. 1 is moved to the left, end 54 (shown in FIG.
7) is made the leading end, and fastener tracks 26, 28
are interlocked in the manner indicated in FIG. 2, to
close the flexible package.
Referring again to FIGS. 2, 7 and 8, a number
of features cooperate to maintain slider 30 captive on
fastener tracks 26~ 28. As can be seen for example in
FIG. 8, a pair of upwardly facing stepped portions 62 are
formed on either side of the slider cavity. Inwardly
extending protrusions 64 are'located at the other end of
the slider. Protrusions 64 and stepped portions 62
engage the bottoms 26a and 28;a (see FIG. 2~ of fastener
tracks 26, 28, as can be seen for example in FIG. 10.
The engagement of the stepped portions 62 and the.
protrusions 64 with the bottoms of the fastener tracks
prevents the slider from being upwardly dislocated from
the fastener tracks.
Referring to FIGS. 1, 3 and 13, the ends of the
fastener tracks are deformed or "crushed" to form stops
68. Preferably, stops 68 are formed by the application
of ultrasonically generated heat and pressure to the ends
of fastener tracks 26, 28. Lt has been found that the
use of present day conduction heat sealing techniques
does not provide the control needed to attain the
intricate, close tolerance design of stop members
according to principles of the present invention.
Further, it has been found that the use of present day
conduction heat sealing techniques immediately adjacent
previously formed stop members tends to distort the stop
members, oftentimes to wn extent rendering the stop
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members unacceptable from a quality control standpoint.
As will be seen herein, stops 68 are configured for
maximum efficiency, having the smallest front elevational
surface area (i.e., the surface area visible in FIGS. 1
and 13, for example), which is adequate for containing
slider 30 on the fastener tracks:
Referring to FIG. 3, the sides of the fastener
tracks are softened and compressed at stop faces or sides
72 so as to impart a pre-selected width w and an
upwelling displacement a above the upper surfaces 26b,
28b of fastener tracks 26, 28 (see FIG. 2). The material
displaced above the upper surface of the fastener tracks
interferes with the top wa2l 44 and ends of slider 30 to
limit its sideways travel.
With referenca to FIG. 3, the .slider stop 68
(that is; the deformed portion of fastener tracks 26, 28)
is carefully configured so as to avoid deformation of the .
bottom surfaces 26a, 28a of the fastener tracks. With
reference to FIG. 1, the lower ends of the fastener
tracks extend undeformed, substantially to the side edges
16, l8 of the flexible package 10. FIG. 1 shows slider
"parked" at a fully opened position, with end 56
contacting the stop 68 located at the right hand end 22
of the flexible package. Stop members 68 and the
25 undisturbed bottom surfaces 26a, 28a of the fastener
tracks in the area of stop members 68 cooperate to
captivate slider 30 on the fastener tracks, preventing
its unintentional removal from flexible package 10.
It is preferred that the bottom edges 26a, 28a
30 remain undeformed also for that portion extending beyond
slider 30, and underneath at least a portion of the right
hand stop 68. With reference to Fig.3, a gap g is formed
between the bottom edges of the fastener tracks and the
top portion 81 of side seal 22. As can be clearly seen
in FIG. 3, the stop 68, formed by ultrasonic techniques,
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is separated by a substantial distance from the side
seal, which is typically formed using conduction heat
seal techniques found to be incompatible with the
precise, high resolution ultrasonic techniques used to
form stop 68. A second stop 68 formed at the left-hand
end 16 of flexible package l9 is constructed in a similar
fashion and extends beyond the end 54 of slider 30 when
the slider is moved fully to the left, closing the upper
end of the flexible package. As will be explained in
greater detail herein,'separation of the "crush"
operation performed on the fastener tracks to form stops
68 from the conduction heat sealing operation to form the
enlarged side seals, allows stops 68 to take on a reduced
size, effectively extending the size of the package
opening, without sacrificing ability of the stops to
effectively retain slider 30 on the fastener tracks.
Referring to FIGS. 1 and 4, side seal 22
includes an upper enlarged or tapered portion 80 having a
width substantially greater than the lower end of side
seal 22, sufficient to underlie the substantial entirety
of slider 3O when the slider is fully moved to the
"parked" position as shown in FIG. 1. The width of the
enlarged, tapered portion 80 ranges between 200% and 400%
(or more for very narrow side seals, e.g., 2 mm or less)
of the width s of side seal 22 and most preferably ranges
between 250% and 3000 of the side seal width s.
The enlarged, tapered end 80 of side seal 22
has a S-shaped or double re-entrant bend contour 84 which
partly defines the package interior. With reference to
FIG, 1l, the curved edge 84 of the enlarged side seal
portion 80 provides a smooth transition at the corner of
the package opening, preventing product entrapment within
the flexible package. As those skilled in the art will
appreciate, the smooth transition at the opening corner
is especially beneficial for'flexible packages, where
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shaking techniques otherwise suitable for rigid packages,
are rendered largely ineffective by flexible panels 12,
14 and especially panels of very thin, unsupported
material which are likely to collapse in use.
The smooth transition prov~.ded by curved edge
84 also deflects or guides product 86 away from slider 30
as product is poured or otherwise-removed from flexible
package 10. This prevents contamination of mating
surfaces of the slider and the fastener tracks, which'
would otherwise deteriorate the ability of slider 30 to
move freely, performing interlocking and unlocking of the
fastener tracks. As indicated in FIG. 12, in prior art
arrangements product 86 is allowed to freely contact the
bottom end of slider 30, a condition which is avoided by
flexible. packages according to principles of the present
invention:
Preferably, fastener tracks 26, 28 are
"crushed" to form stop member 68, using conventional
ultrasonic heating equipment which allows for a highly
accurate shaping of the stop member as well as withdrawal
of the deformation area away from the bottom surfaces
26a, 28a as shown, for example, in FIG. 3. As can be
seen for example in FIG.,1, the width of stop member 68
is considerably less than the enlarged tapered portion 80
of side eal 22, and preferably is of a smaller width
than that of the narrower major portion of side seal 22.
With reference to FIG. 1, the width d of stop member 68
is less than the width s of side seal 22. Preferably,
stop member width d ranges between 50°s and 200% of the
width s of side seal 22. Preferably, the width w of the
stop member 68 (i.e., the "crush" dimension) ranges
between 25% and 800 of the width z of the fastener
tracks, as illustrated in FIG. 3. The amount of upward
displacement or upwelling a is approximately at least as
great as the thickness of upper wall 44: It should be
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kept in mind that the total mass of the stop must be
sufficient to hold the slider captive.
The stop member 68; in addition to having a
reduced width d in front elevational view and a small
width w in end view (see FTG. 3), has a sufficiently
smaller mass and frontal surface area than stops employed
in the prior art. This construction allows the slide 30
to be moved to an extreme position immediately adjacent
the edge 22 of flexible package 10; thus maximizing tM.e
package opening, allowing for easier removal of the
package contents. This reduced size of stop 68 also
contributes to the precision of the ultrasonic heating
and formation of the stop member, needed to attain
required precise dimensions. Further, from a
manufacturing standpoint, the dwell time to melt and
shape the stop 68 is substantially reduced, contributing
to the overall efficiency for the package manufacturer.
Prior art stop members have been formed by
"crushing~~ the entire fastener profile, including the
bottom surfaces 26a, 28a. In addition, even if
ultrasonic techniques are employed for the stop member,
prior art side seals (formed using conductionyheat seal
techniques and much larger, oftentimes three to four
times larger than side seals according to the present
invention) were typically overlaid with the stop,
contributing to a substantial distortion of the stop
structure. Even if the prior art side seals were made to
stop short of the fastener tracks, the relatively high
level of conduction heating in the immediate proximity of
the stop have been found to cause a distortion of the
stop, degrading control over: its size and shape. These
disadvantages are avoided with practice of the present
invention, where the small, compact size of the stop is
employed, and the gap g is formed between undeformed
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fastener bottom surfaces 26a; 28a and the enlarged seal
portion 80.
Turning now to FIGS. 4, 9 and l0, and initially
to FIG. 9, the fastener tracks are preferably formed from
a sub-assembly generally indicated at 70 in which the
fastener tracks 26, 28 are provided with corresponding
fastener flanges 72; 74. The fastener flanges 72, 74 are
coextensive with the fastener tracks 26 ,28 and take the
form of a plastic web to be heat sealed to the panels 12,
14. As can be seen in FIG. 9, fastener flange 74 is
shorter'in height than fastener flange 72, so as to
accommodate the preferred hermetic seal arrangement shown
in FIG. 10.
The fastener flanges 72, 74 are heat sealed to
panels 12, 14. With reference to FIGS. 4 and'10, '
fastener flange 72 is welded or otherwise mechanically
sealed to panel l2 at weld band 78. As shown at the
upper portion of FIG. 10; the upper ends of panels 12, 14
are joined to the outer outwardly facing surfaces of
fastener flanges 72, 74 at points intermediate the
fastener tracks and peelable seal 36. Band 36 preferably
comprises a hermetic peelable seal formed by the joinder
of panel 14 to the inside face 72a of fastener flange 72
(see FIGS. 10 and 10a). Panel 12 is sealed to the
opposite outside face of the fastener flange as
schematically indicated in FIG. 10. In FIG. lOa the
components of the peelable seal 36 are shown, with film
12, which plays no part in the preferred peelable seal,
being shown in phantom.
Variations of the peelable seal are also
contemplated by the present invention. For example, in
FIG. 10b, the flanges 72, 74 of the fastener arrangement
are joined with a peelable seal. The upper ends of these
flanges are heat sealed to panels 12, l4 as shown. In
FIG. lOc a further alternative is shown with the peelable
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seal 36 being formed at the joinder of lower portions of
panels 12, 14. the upper portions of panels 12, 14 are
heat sealed to fastener flanges 72, 74.
As will now be appreciated, the enlarged,
tapered end portions 80 of side seal 22 cooperate with
other features of flexible package l0 to provide a number
of important advantages. More specifically, the enlarged
tapered end portions 80 provide a smooth transition o
the interior of flexible package 10 preventing product
entrapment in the slider and fastener track surfaces when
product is poured or otherwise dispensed. In addition,
the enlarged tapered portion 80 helps to secure slider 30
about tracks 26, 28 by maintaining a clearance from
bottom surfaces 26a, 28a of the fastener tracks.
Further, the enlarged tapered portions 80 of side seals
22 strengthen and rigidify edge portions of panels 12, 14
in the immediate area of the parked position of slide 30.
Often, the greatest amount of force applied by
the user to slider 30 occurs at the closing of the
slider, when the fastener tracks are unlocked or
separated from one another. When the slider 30 is in the
middle of its travel along the fastener tracks, the user
is provided with a sensation of the proper direction of
slider movement. However; when the slider 30 is in the
parked position, and especially in the "parked open"
position shown in FIG. 1, the user's initial application
of force may be misdirected. The enlarged tapered
portion 80 provides added stiffness and rigidity to the
flexible package at the initial point where pressure is
applied to the slider, thus further contributing to the
assurance that secure engagement will be maintained
between slider 30 and the tracks 26, 28.
With reference to FIG. 4, a consumer desiring
to close the flexible package will grasp the enlarged
side seal portion 80, pulling in the direction of arrow
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81 while pulling or pushing slider 30 in the direction of
arrow 31. The added stiffness and rigidity offered by
enlarged side seal portion 80 is provided at a point of
optimal effectiveness to react in an appropriate manner
to forces applied to slider 30 and to overcome any
resistance of the tracks 24, 26 to resume a mating,
interlocked condition as the fastener tracks are
interlocked. Those skilled in the art will appreciate
that the "rolling resistance" or dynamic resistance to
movement of slider 30 is oftentimes lower than the
initial static resistance, opposing movement of the
slider away from the fully opened parked position shown,
for example, in FIG. 4.
The added stiffness and rigidity imparted to
the flexible package 10 and especially panels 12, 14 by
enlarged side seal portion 80 results in other advantages
when lightweight panels 12, 14 are employed. For
example, panels of the single polyolefin type where no
laminate film (such as PET or NYLON) is used to stiffen
and support the support panel, have oftentimes excluded
the use of sliding zippers, since minimum stiffness and
rigidity needed to operate a fastener slider was not
available. However, with enlarged side seal portions
according to principles of the present invention,
adequate stiffness is provided, even for lightweight, so-
called "single" films.
As indicated in FIG. 10, flanges 72, 74 are
joined to respective panels 12, 14, preferably at their
lower ends, so as to prevent product from entering
between flange 72 and panel l2, as well as between flange
74 and panel 14. In certain applications this may not be
a critical requirement. In FIG. 10, the upper portion of
panel 12 is shown for illustrative purposes as spaced
from the lower end of flange 72: In practice, it is
generally preferred that this spacing be eliminated, with
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panel 12 being in intimate contact with flange 72.
Similarly, any gap between panel 14 and the lower end of
fastener flange 74 is preferably eliminated. Although it
is most preferred that the peelable seal be formed by
joining panel 14 to fastener flange 72, the peelable
seal, preferably a hermetic seal, can be formed between
the fastener flanges 72, 74 or directly between the
panels 12, 14, although these alternative constructions
are less preferred than the arrangement shown in FIG.!10.
Turning now to FIG. 13, flexible package 10 is
shown constructed with the panels 12, 14, side seal 22,
upper enlarged side seal portion 80 and fastener tracks
26, 28, as described above. The fastener tracks 26, 28
are preferably joined to flanges 72, 74 (not visible in
FIG. 13). FIG. l3 schematically illustrates commercial
fabrication of flexible package l0. As will be
appreciated by those skilled in the art, practical
commercial assembly requires recognition of tolerances of
the equipment and materials used to construct a viable
commercial product. For example, tracks 26, 28 are
ultimately mechanically coupled to panels 12, 14 using
conduction heat seal tooling. A gap 110 shown in FIG.
13 represents the tolerance range or margin of error for
tool alignment used to secure the fastener tracks 26, 28.
As mentioned, it is preferred that the upper end of
enlarged side seal portion 80 be spaced below the lower
ends of the fastener tracks, such as the lower end 26a of
fastener track 26 visible in FIG. 13: Further, it is
preferred that the gapg continue beyond the end 56 of
slider 30.
A gap 116 represents a tolerance range or
margin of error for the desired positioning of the upper
end of enlarged side seal portion 80; to provide
clearance for the bottom edge of slider 30. As
illustrated in FIG. 13, the upper end of enlarged side
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seal portion 80 falls at an outermost limit of its
tolerance range. Preferably, the upper end of enlarged
side seal portion 80 is within the gap 116, rather than
to one end thereof. The gap 116 also accounts for any
cant or angular mis-positioning or mis-alignment where
the upper end of side seal 80 may be angled slightly from
a position parallel to the fastener tracks, as may be
encountered in a practical commercial environment.
A band 120 shown in FIG. 13 represents a
conduction heat seal of the fastener flange to the panels
12 or l4. This conduction heat seal 120 provides the
principal mechanical attachment of the fastener track
assembly to the package panels: Band 36 is the peelable
seal, preferably a hermetic seal, between panel 14 and
fastener flange 72. A gap 124 represents the desired
production spacing between production seal 120 and
peelable seal 36. The remaining band 128 represents the
production tolerance range or margin of error for
positioning of peelable seal 36 with respect to the
package panels:
In one commercial embodiment, flexible package
10 comprises a plastic bag having a width of approxi-
mately 6.5 inches from side edge to side edge and a total
overall height of approximately 10.75 inches. The
fastener tracks 26, 28 have a height of approximately 4
millimeters, with gaps 110, 116 each having a height of 2
millimeters. As shown in the upper right hand corner of
FIG. 13, stop 68 projects a distance a above the top edge
of the fastener tracks. Ln FIG. 13, only the top edge
26b is visible. With reference to FIG. 10, the upper
ends of panels 12, 14 are preferably spaced a distance p
from the bottom edges of the fastener tracks, ranging
between 2 and 3 millimeters. The conduction heat seal
120 and the peelable seal 36 each have a height of 6
millimeters, and gap 124 located between the two, has a
CA 02421999 2003-03-13
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height of 2 millimeters. The desired spacing between
conduction heat seal 120 and peelable seal 36 has a
maximum value of 2 millimeters and a minimum value
required to prevent overlap of the conduction heat seal
and peelable seal. The side seal 22 has a width ranging
between 3 and 8 millimeters and the stop 68 has a width
(see reference character d in FIG. 1) ranging between 2.0
and 8.0 mm. As can be seen with reference to FIG. 13,
the upper end of side seal 22 is spaced a substantial
distance below the upper edge of the flexible package.
This spacing ranges between a minimum value equal to the
combined height of the fastener tracks and gap 110, and a
maximum value equal to the combined height of the
fastener tracks, gap 11O and gap 116.
Referring to FIG. 14, several alternative
features are shown with reference to a flexible package
130. The right hand portion of flexible package 130 is
identical to flexible package l0, described above; except
for the addition of a peg hole 132 formed in the enlarged
side seal portion 80. Flexible package 130 has a left
side seal 20 as described above with respect to FIG. 1.
However, in the flexible package 130, the upper end of
side seal 20 is enlarged at 138 in a manner similar to
that of enlarged side seal portion 80. An optional peg
hole 140 is formed in the enlarged side seal portion 138.
Although the peg holes 132, 140 are shown having a
circular shape, virtually any shape (e.g., oval) can be
used, as well. Peg holes 132; 140 can be formed by
punching before or after the side seals are fully formed,
it being preferred that the upper ends of the side seals
provide a complete sealing of the panels end other
components of the flexible package. It will be
appreciated by those skilled in the art that the holes
add heat relief to the enlarged side seal portion. This
helps preserve the uniformity of the tapered area and of
CA 02421999 2003-03-13
-20-
the dimensioning of gap g, as well as the uniformity of
shrinkage which helps control manufacture on a production
basis. If desired, the heat sealing die can be made
hollow in the region of the peg holes, even in'the
absence of peg hole features to attain further heat
relief advantages. It may also be preferable in some
instances to form the peg holes 132, 140 as part of the
formation of the side seals using, in effect, a therma!1
cutting or thermal punching technique. With the
inclusion of two peg holes 132, 140, flexible package 130
can provide an improved presentation of art work or other
indicia carried on the panels of the flexible package.
It is generally preferred that textual and
graphic information be oriented generally perpendicular
to the side edges of the flexible package. If only one
peg hole is provided, the package will tend to hang
rotated in a vertical plane, according to the
distribution of product within the flexible package.
With support given to two peg holes 132; 140, the
flexible package is oriented in an upright position,
making it easier to read the text and graphical
information carried on the package. If desired, the text
and graphical information printed on the rear panel can
be inverted so that a consumer can "flip" the package to
inspect the rear panel, without having to remove the
package from the support pegs passing through peg holds
132, 140.
Although the package opening, fastener tracks
and related features are shown at the upper end of the
flexible package, the present invention is intended to
cover arrangements in which the opening and related
structure is provided on the side or bottom of the
flexible package.
Referring now to FIGS. 15-25 and initially to
FIG. 25, an improved package according to principles of
CA 02421999 2003-03-13
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the present invention, is shown. Package 199 includes
the features of flexible package 10, described above and
in addition includes a shroud portion 204 extending above
line of weakness 208 formed in panels 12, 14. Line of
weakness 208 can be formed using, available conventional
techniques, and is preferably formed using laser scoring
techniques. Preferably, line of weakness 208 extends
across the width of flexible package 199, from one side
edge to the other. As shown in FIG. 25, line of weakness
208 extends to edge l8; located at side seal 22. If
desired, side seal 22 can be replaced by side seal 20.
Preferably, shroud 204 is made for easy tear-
away removal in an intuitive manual operation not
requiring special directions. Preferably, a notch 210 is
formed in edge 18, and is located slightly above stop 68.
An optional angled or diagonal line of weakness 212
extends from notch 210 to an opening 214 which surrounds
slider 30. Opening 214 is illustrated as a rectangle
with rounded corners. Opening 214 can however take on
other shapes, such as that of a circle or teardrop, for
example. Opening 214 relaxes the strain in the shroud
portion of the flexible package caused by relatively
large-sized slide members. It is preferred that the
opening 214 be formed in the web prior to joining with
fastener tracks. Accordingly, careful registration of
the opening 214 is needed to insure the desired finished
flexible package is produced.
Preferably, slider 30'is located at a fully
closed position along the fastener tracks and is
surrounded by opening 214 at the closed position. In
order to gain access to the package contents, a user
grasps the upper edge of shroud 204 causing an initially
tearing at notch 210. Tearing continues along diagonal
line 212 and enters opening 214, continuing along opening
214 to line 208. With continued tearing across the width
CA 02421999 2003-03-13
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of package 199, the shroud 204 is removed, leaving a
package substantially similar to the packages described
above in FIGS. 1-14.
Referring again to FIG. 25, shroud 204 includes
an upper fin seal 220 and aside fin seal portion 222.
Preferably, the upper fin seal 220 inside fin seal 222
are formed in separate sealing operations and are made to
slightly overlap one another for package integrity an
sealing of the package interior. The bottom of side fin
seal 222 is terminated at or slightly above end stop 68.
It is most preferred that side fin seal 222 be terminated
slightly above end stop 68 to avoid interfering with the
controlled formation of the end stop which, as pointed
out above, has a shape and position providing novel
advantages. Notch 210 in the preferred embodiment shown
in FIG. 25 is formed at the lower end of side fin seal
222. If desired, notch 210 could be formed in a gap
between end stop 68 and a side fin seal shortened with
respect to the side fin seal illustrated in FIG. 25.
Turning now to FIGS. 15-18 a flexible package
230 is shown. Package 230 is substantially identical to
package 199 described above, except that opening 214 does
not directly communicate with diagonal line 212. Tearing
of package 230 to remove shroud 204 is initiated at notch
210 and continues along diagonal line 212 to a point of
intersection with line.of weakness 208. If desired, the
portion of weakness line 208 designated by reference
numeral 232, line between diagonal line 212 and edge 18
can be omitted, if desired. Further, weakening line 208
and diagonal line 212 can be formed in a single operation
using conventional techniques such as laser cutting. As
a further alternative, diagonal line 212 can be made to
curve either along its entire length, or at the point of
intersection with weakening line 208. FIG. 15 shows a
central peg hole 234 is formed in upper fin seal 220.
CA 02421999 2003-03-13
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Referring now to FIG. 19, flexible package 240
is substantially identical to flexible package 230,
except for the omission of opening 214. Arrangement of
FIG. 19 is preferably employed where the width of slider
30 is reduced, or the shroud 204 is sufficiently flexible
or has an enlarged cross section so as to completely
enclose slider 30 without requiring an opening to relax
tension in the material forming the shroud.
Referring now to FIG: 20, a cross ection of
flexible package 199 is shown. Preferably, shroud 204 is
formed as a continuous integral extension of panels 12,
14, the upper free edges of which are joined together to
form upper fin seal 220.
Referring to FIG. 21, exemplary tooling to form
the package 199 are shown. For example; a pair of upper
seal bars 250 form upper fin seal 220 while a pair of
intermediate seal bars 252 join panels 12, 14 to fastener
flanges 72, 74. Lower seal bars 254 form the peel seal
36 and weld band 78 FIG. 20). The bottom of package
199, as is preferred, with the other flexible packages
shown herein, is formed by a dead fold.258.
Referring now to FIG. 22, a flexible package
260 is substantially identical to flexible package 230 of
FIG. 18, except for a curved line of weakness 264 joining
notch 210 with weakening line 208.
FIG. 23 shows a flexible package 270 similar to
that of flexible package 230, except that a large or
tapered side seals are provided at each side of the
package. Peg holes 132, 140 are formed in the tapered
side seal portions and if desired an optionally central
peg hole 234 can be formed in upper fin seal portion f20.
As with the other embodiments shown herein, it is
generally preferred that the enlarged or tapered side
seal portions stop short of the line of weakness 208.
CA 02421999 2003-03-13
-24-
FIG. 24 is a cross-sectional view of an
optional flexible package 280 substantially identical to
flexible package 199; described above, except that a
shroud member 282 is separately formed from panels 12, 14
and is joined to the upper ends of the panels by
conventional welding or other joining techniques. Most
preferably, shroud 282 is joined to the upper ends ofi
panels 12, 14 at the point of sealing with flanges 72,~'~
74. The weakening line for removal of shroud of 282 cyan
be formed either above or below the point of sealing with
remainder of the flexible package.
It is generally preferred that textual and
graphic information be oriented generally perpendicular
to the side edges of the flexible package. If only one
peg hole is provided, the package will tend to hang
rotated in a vertical plane, according to the
distribution of product within the flexible package.
With support given to two peg holes 132, 140, the
flexible package is oriented in an upright position,
making it easier to read the text and graphical
information carried on the package. If desired, the text
and graphical information printed on the rear panel can
be inverted so that a consumer can "flip" the package to
inspect the rear panel, without having to remove the
package from the support pegs passing through peg holds
132, 140.
Although the package opening, fastener tracks
and related features are shown at the upper end of the
flexible package, the improved flexible package is
intended to cover arrangements in which the opening and
related structure is provided on the side or bottom of
the flexible package.
Turning now to FIG. 26 and following, apparatus
for manufacturing improved flexible packages having slide
closures will now be described. As will be seen herein,
CA 02421999 2003-03-13
-25-
the apparatus according to principles of the present
invention, generally indicated at 300 employs a
horizontal form fill seal arrangement with the in-line
application of mated fastener tracks to a folded web.
Apparatus 300 bring all of the required packaging
components together, for assembly, at the point of fill.
Referring to FIGS. 26 and 27; apparatus 300!
includes a web supply roll 304 providing a supply of web
material 306 preferably comprising a conventional plastic
packaging film. Web material 306 is advanced in the
direction'of arrow 308. Punches 312 are schematically
indicated and form the openings 214 on opposed bag panel
portions 12, 14 (see FIG. 15). Also, indicated in FIG.
29 are diamond shape cutouts 324 formed by punches
schematically indicated in FIG. 26 at 314. In FIG. 28
dotted line 318 indicates a crease or a fold line about
which web 206 is folded about plow 330 (see FIG. 29) to
form a "dead fold" 32O at the bottom of the finished bag,
as shown in FIG. 29. The lines 326 running generally
transverse of web 206 indicate severing lines which
divide one bag portion from another, the bag portions
preferably being serially formed in a bag chain from a
common web. After severing, the diamond cutouts 324
become pairs of opposed tear notches 211 shown for
example in FIG. 39.
As mentioned, the web is initially formed so as
to have a "dead fold" at its bottom end. If desired,
processing can continue, eventually producing separate
bags having dead fold bottoms. As a preferred
alternative, a gusset blade 340 can be employed in the
manner illustrated in FIGS: 30b and 31 to form a gusset
in the bottom of the folded web. The W-shaped gusset or
pleated bottom is shown in greater detail in FIG. 31, and
an alternative "Delta-fold" gusset is shown in FIG. 33.
The pleated bottoms 324 are sealed as indicated in FIG.
CA 02421999 2003-03-13
-26-
32 using gusset sealing dies 327. The dies 327 include
upstanding saw tooth portions 328 configured to seal the
corners at side edges of the individual, separated bags.
FIG. 33 shows the right-hand bottom corner of one bag
with an angled seal edge.
Referring to FIGS. 26; 30a and 36, a supply of
mated fastener track 210 (preferably comprising fastener
tracks 26, 28) is supplied on roll 350. Preferably, the
fastener tracks include respective mounting flanges which
overlie one another, and which extend along the mated
fastener tracks. As can be seen, in FIG. 36 the mounting
flanges 72, 74 are of unequal height (with the food
package viewed in an upright po ition) and extend from
the fastener tracks 26, 28 different amounts. Further
details concerning the construction and operation of the
mated fastener tracks 210 and slider 30 of the preferred
embodiment may be obtained with reference to United
States Patent No. 6,047,450, the disclosure of which is
herein incorporated by reference as if fully set forth
herein.
With reference to FIGS. 30a and 34, the mated
fastener track 210 is fed through a roller guides 354 to
enter a work station generally indicated at 360 for
forming stops 68 in the mated fastener track. An
adjacent work station 364 is provided for applying slide
members 30 to the fastener track.
Turning again to FIG. 26 and with additional
reference to FIG. 30b, the prepared zipper track (with
end stops and slider members) and the folded web is
brought together at fastener sealing station 400. FIG.
shows a cross section of the web and fastener track
prior to entering the sealing station. As shown, web 306
is folded into a general V-shape to form opposed front
and rear panels 402, 404 joined by a fold. With
35 additional reference to FIG. 47, the mated fastener track
CA 02421999 2003-03-13
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includes mated male and female track members 26, 28 as
described above, for example, with reference to FIG. 2.
Track members 26, 28 include a longer depending flange 72
and a shorter depending flange 74, respectively. The
outer sides of flanges 72, 74 are joined to the opposing
interior surface of panels 402, 404. As will be seen
herein, the lower portion of flange 72 is joined to panel
402 to form a peel seal.
The initial sealing of the prepared fastener
track to the side wall panels is carried out at station
400, preferably using sealing tool or die 410 adjacent
panel 402 and sealing die 412 adjacent panel 404. As
will be seen herein, panel 402 preferably comprises the
front panel of the flexible package while panel 404
comprise the opposed, rear side of the package. If
desired, printing on the front and rear panels 402, 404
could be interchanged one for the other.
Referring to FIGS. 30b and 36,,sealing tools
410, 412 are heated to a temperature sufficient to cause
joining of flanges 72, 74 to panel 402. Preferably,
sealing is accomplished with the application of pressure
and accordingly sealing tool 412 is employed as a back up
to sealing tool 410. Preferably, both sealing tools 410,
412 are advanced toward one another, toward separator
tool 416. In order to prevent inadvertent sealing of
fastener flanges 72, 74 by sealing tool 410, an unheated
or cooled separator tool 416 is temporarily placed
between flanges ?2, 74.
As mentioned above, it is generally preferred
that the fastener tracks be provided on supply reel 350
in a mated form, with the crushing operation to form end
stops 68 being performed at an early stage of assembly.
Preferably, the fastener closure members 30 are applied
to the mated fastener. tracks, at a site located
immediately downstream of station 360. The mated
CA 02421999 2003-03-13
_2g_
fastener tracks with formed end stops and fastener
closure members are then advanced to station 400 and, as
indicated in FIG. 30b are joined to the package side
walls. As indicated at station 400 in FIG: 30b, a pair
of cooperating plates 414a, 414b are provided to open or
separate the mated tracks in the manner shown in FIGS.
38a, 38b. A plurality of guides 415 fold back the upper
portion of the plastic webs to expose the mated fastener
tracks in preparation for an opening or disengagement!
operation. As indicated, plates 414a, 414b cooperate to
pinch or compress the lower ends of fastener members 26,
28. As illustrated in FIG: 38b, this causes the closure
members to pivot or "rock" causing their interengaging
portions to disengage. Referring again to FIG. 30b it is
preferred that the plate members 414a, 414b operate on a
limited defined portion of the zipper tracks.
As a less preferred alternative, the fastener
tracks could be provided in a separate, unmated condition
or, if provided on reel 350 in a mated condition could be
opened or disengaged early on, either before or after end
forming station 360, in a continuous disengagement
operation. It may be necessary to relocate closure
installation station 364 to a downstream position at a
point where the separate fastener tracks become mated.
Turning now to FIG. 37, the joined web and
prepared fastener tracks are advanced to the station 430,
where pairs of vertical sealing bars 432 cooperate to
form side seals for the flexible package. With
additional reference to FIG. 28, side seals are formed
along lines 326 and with reference to FIG: 39, for
example, the side seals of the completed flexible package
are indicated by 20, 22. Referring also to FIG. 25, it
can be seen that the side seals stop short of end stop
68, so as to provide an intervening spacing. In this
manner, unwanted deformation of the end stop is avoided
CA 02421999 2003-03-13
-29-
as the side seals are formed. Accordingly, the vertical
sealing bars 432 are foreshortened with respect to the
overall height of the flexible package.
In the preferred embodiment, sealing bars 432
have hea loadings optimized for rapid assembly.
Accordingly, it has been found desirable to add vertical
cooling bars 434 at a downstream position to withdraw
heat from the side seals. As mentioned above, the
vertical sealing bars are foreshortened with respect to
the overall height of the flexible package. The vertical
cooling bars could also be foreshortened in a similar
manner, since their function is to withdraw excess heat
lingering after fusion of the side seals is completed.
Alternatively, the cooling bars can extend upward beyond
the side seals, if desired. If desired, additional
operations such as operating on the side panels with
punches while the bag chain is temporarily stopped at
station 430. Punches can be employed, for example, to
form side holes 132, 140 as shown in FIG . 14 or center
hole 234 as shown, for example, in FLG. 15.
The lower portions of the flexible packages or
bags are now fully formed except for being connected
together in serial succession in the form of a bag chain.
Tap filling and final sealing of the upper end of the
flexible packages remains to be accomplished. If
desired, the filling and final, top sealing could be
performed with the flexible packages serially connected
in a bag chain. However, it is preferred that the
individual, partially formed flexible packages be
separated from one another at station 460.
With reference to FIG. 4O, a series of knives
462 are employed to sever the bag chain to separate the
empty, partially formed flexible packages at the end of
the bag chain. Knives 462, located downstream of drive
rollers 461, are aligned so as to intersect the diamond-
CA 02421999 2003-03-13
-30-
shaped openings 324, forming opposed V-shaped notches in
side seals of adjacent flexible packages.
With reference to FIG. 39, for example, the
notches formed are identified by reference numeral 211.
It is generally preferred that V-shaped notches be formed
in both side seals of the flexible packages, and that the
portions of the bag chain be supported prior to the
severing operation so as to maintain positional control
of the severed flexible packages. Any of a number of!
conventional supports; can be employed for the purpose.
Referring to FIGS. 44a, 44b, upper suction cup
assemblies 468 are diagrammatically illustrated as
spanning a pair of partially formed flexible packages.
Preferably, a pair of suction cup members 468 are
employed, on opposite sides the flexible packages so
that, by withdrawing the suction cups away from one
another; the upper ends of the flexible packages are
opened in preparation for.filling. At station 480,
interior portions of the flexible packages are inflated
in a gas flushing operation using flushing members 481
having gas inlets 483. Any suitable gas mixture could be
employed, although it is generally preferred that an
inert gas f'or Bettering or otherwise displacing oxygen is
employed. The separated, but incompletely formed,
flexible packages are advanced to filling station 500.
With reference to FTGS. 41, 42 and 44c, filling
operations employ conventional duck bill members 506. As
schematically indicated in FIG. 42, filling is carried
out between the fastener tracks with the bottom end 508
of the duck bill member being positioned at, or more
preferably below the fastener tracks. Referring to FIG.
43, an upper opening is provided by the duck bill
arrangement nested between the zipper tracks. The
opening is relatively large, so as to allow manufacturers
to deliver products into the flexible packages at
CA 02421999 2003-03-13
-31-
relatively high production line speeds, a feature
attractive for mass production.
Turning now to FIGS. 41 and 42, the duck bill
filling apparatus 506 preferably has an articulated clam
shell configuration. The bottom ends 508 of the clam
shell members are initially brought together so as to
facilitate penetration into the interior of the flexible
package. Once the filling apparatus is successfully
inserted into the package interior, the filling apparatus.
is advanced until the lower ends 508 are plunged below
the lower end of the fastener tracks. The clam shell
members are then opened in the manner indicated in FIG.
42 to allow product 520 to drop into the flexible
package. FIG 43 shows the relatively large filling
opening it has made possible.
When filling of the flexible package is
completed, final top sealing and peel seal operations are
performed. With reference to FIG. 26, the flexible
packages are advanced to station 600 containing
conventional linear stretching apparatus 602. The
flexible packages are then advanced to sealing station
700 where the top of the shroud covering the mated zipper
tracks is formed. With reference to FIGS. 45 and 46, two
pairs of sealing bars are employed. The uppermost pair
of sealing bars, identified at 710 form the upper seal of
the shroud indicated at 714 in FIG. 47. A second pair of
sealing tools identified at 718 form the peel seal
between the lower portion flange 72 and panel 404.
A flexible package having a removable shroud
covering a slide fastener has been shown. However, it
should be readily apparent to those skilled in the art
that apparatus 300 can readily form, fill and seal
flexible packages, such as those illustrated above in
FIG. 1, for example , which lack the shroud feature.
CA 02421999 2003-03-13
-32-
As indicated, for example, in FIG. 35 the
longer flange is preferably associated with the male
fastener track 26. As seen above, the longer flange, at
its bottom end, forms a peel seal with a package panel.
The shorter flange; associated with the female fastener
track 28 is permanently joined to the package panel at an
early stage of operation. The anchoring of the flange
carrying the female track 28 onto the side panel of the
bag and the application of the peelable seal on that same
side panel of the bag, associated with the male fastener
track, provides a unique insulation of the reclosable top
the flexible package during the filling and gas flushing.
This construction creates a laminar flow of the purging
gas (preferably nitrogen or carbon dioxide) that
effectively sweeps residual oxygen from the unfilled
flexible package. As those skilled in the art of
packaging foods and other products are aware, this
feature of the invention is oftentimes found essential to
provide a modified atmosphere for packaging, which
preserves the freshness of the product being packaged.
The drawings and the foregoing descriptions are
not intended to represent the only forms of the invention
in regard to the details of its construction and manner
of operation. Changes in form and in the proportion of
parts, as well as the substitution of equivalents, are
contemplated as circumstances may suggest or render
expedient; and although specific terms have been
employed, they are intended in a generic and descriptive
sense only and not for the purposes of limitation, the
scope of the invention being delineated by the following
claims.
