U.S. patent application number 11/622185 was filed with the patent office on 2007-05-17 for methods of making and/or filling reclosable bags.
This patent application is currently assigned to Velcro Industries B.V, a corporation of the Netherlands. Invention is credited to Gregory A. Carr, William H. Shepard.
Application Number | 20070107380 11/622185 |
Document ID | / |
Family ID | 23057148 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070107380 |
Kind Code |
A1 |
Shepard; William H. ; et
al. |
May 17, 2007 |
Methods of Making and/or Filling Reclosable Bags
Abstract
Methods of forming and/or filling recloseable bags are
disclosed. In some embodiments, the methods include attaching a bag
closure strip along one longitudinal edge of a length of bag film,
and forming from the length of bag film, a bag having an open end,
two broad, opposing faces and a flap. In certain embodiments, the
flap is attached to an edge of one of the broad faces along the
open end and extending between sealed edges of the bag.
Inventors: |
Shepard; William H.;
(Amherst, NH) ; Carr; Gregory A.; (Nashua,
NH) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Assignee: |
Velcro Industries B.V, a
corporation of the Netherlands
|
Family ID: |
23057148 |
Appl. No.: |
11/622185 |
Filed: |
January 11, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10662266 |
Sep 15, 2003 |
7186025 |
|
|
11622185 |
Jan 11, 2007 |
|
|
|
PCT/US02/08055 |
Mar 15, 2002 |
|
|
|
10662266 |
Sep 15, 2003 |
|
|
|
60276567 |
Mar 15, 2001 |
|
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Current U.S.
Class: |
53/412 ; 53/450;
53/451 |
Current CPC
Class: |
B65B 9/20 20130101; B65B
9/2056 20130101; B65B 9/093 20130101; B65B 9/213 20130101; B65D
33/18 20130101; B31B 70/8132 20170801; B31B 2160/20 20170801; B65D
33/24 20130101; B65B 51/303 20130101; B65B 9/087 20130101; B31B
2155/00 20170801; B65D 31/10 20130101; B65D 75/008 20130101; B65B
61/188 20130101; B65D 2313/02 20130101; B65B 9/2042 20130101 |
Class at
Publication: |
053/412 ;
053/451; 053/450 |
International
Class: |
B65B 61/18 20060101
B65B061/18; B65B 9/00 20060101 B65B009/00 |
Claims
1. A method of forming fillable, reclosable bags, the method
comprising attaching a bag closure strip along one longitudinal
edge of a length of bag film; and forming from the length of bag
film, a bag having an open end, two broad, opposing faces, and a
flap with an inwardly-extending fold, the flap attached to an edge
of one of the broad faces along the open end and extending between
sealed edges of the bag, the open end of the bag defining a fill
opening between the closure strip and the other of the broad faces
of the bag.
2. The method of claim 1 wherein the closure strip comprises an
elongated strip-form base with two spaced-apart, parallel, mating
bands of fastener elements disposed on a common face of the base,
the base folded along its length between the bands of fastener
elements to maintain the fastener elements in engagement while the
bag is being formed.
3. The method of claim 2 wherein one of the mating bands of
fastener elements comprises hooks, and the other of the mating
bands of fastener elements comprises hook-engageable fibers.
4. The method of claim 3 wherein the band with fibers comprises a
non-woven web of fiber.
5. The method of claim 1 wherein forming the bag comprises folding
the length of bag film to form both broad face panels and the
flap.
6. The method of claim 1 wherein the bag is formed after the
closure strip is attached to the bag film.
7. The method of claim 1 wherein the closure strip extends across
the bag between the sealed edges of the bag.
8. The method of claim 1 wherein forming the bag comprises cutting
the length of film and the bag closure strip to selected lengths
after the bag closure strip is attached, and sealing cut ends of
the film and closure strip to form the sealed edges of the bag.
9. The method of claim 1 further comprising filling the bag with a
quantity of contents; and forming a seal along the open end of the
filled bag along the closure strip, with the flap forming an
expandable gusset of the filled bag.
10. A method of filling and sealing a reclosable bag, the method
comprising providing a bag comprising a body having an open end,
two opposing, broad face panels defining a volume therebetween for
holding a quantity of contents, and a flap attached to one of the
broad face panels along the open end, the flap having an
inwardly-facing fold for forming an expandable gusset between the
broad face panels after the open end is sealed; and a reclosable
bag closure secured to a free edge of the flap and having an
exposed side defining one side of a fill opening at the open end of
the bag; filling the bag with contents through the fill opening;
and sealing the exposed side of the closure strip to the other of
the broad face panels of the bag, to permanently close the fill
opening.
11. A method of vertically forming, filling and sealing recloseable
bags, the method comprising attaching a bag closure strip along one
longitudinal edge of a length of bag film; forming from the length
of bag film a bag having, two broad, opposing faces and an
expandable gusset between the broad faces adjacent the closure
strip; filling the bag with a quantity of contents; and forming a
seal along an edge of the bag between the broad faces and crossing
the closure strip at one end of the expandable gusset, to seal the
filled bag.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/662,266, filed Sep. 15, 2003, which is a continuation
of PCT/US02/08055, filed Mar. 15, 2002, which claims priority to
U.S. Provisional Patent Application Ser. No. 60/276,567, filed Mar.
15, 2001, which are incorporated by reference herein.
TECHNICAL FIELD
[0002] This invention relates generally to reclosable bags, and to
methods of making and/or filling such bags.
BACKGROUND
[0003] Convenience packaging, particularly for foodstuffs and bulk
materials, frequently involves the use of bags or pouches. These
bags can be advantageously constructed with side or bottom gussets
to make them able to be set upright on a horizontal supporting
surface, for filling, display or storage. It is common to refer to
bags with bottom expansion panels and sealed side and top edges as
`pouches`.
[0004] More recently, bags have been produced with expansion panels
at both top and bottom, and vertical side seals. Examples of these
bags are marketed under the trade name "Flex-Can", for example, and
are known for their ability to be conveniently stacked one on top
of another, like cans. Both the top and bottom panels of these bags
expand substantially and simultaneously as the bags are filled,
such that the sides of the bag separate at both top and bottom, in
some cases remaining generally parallel and vertical. As filled,
the bag and its contents can exhibit significant structural
stability, enabling stacking and convenient handling, with very
little head space above the contents.
SUMMARY
[0005] We have realized that it is possible to equip a gusseted bag
with a reclosable seal adjacent its gusset and have the closure
function despite the expansion and contraction of the gusset.
[0006] The invention features a reclosable, gusseted bag, having an
opening defined adjacent an expansion gusset.
[0007] According to one aspect of the invention, a gusseted bag has
a body with opposing broad face panels defining a volume
therebetween for holding a quantity of contents, an end of the body
forming an expandable gusset between the broad face panels, and a
reclosable bag closure between the expandable gusset and a
corresponding one of the adjacent edge regions of one of the broad
face panels, such that when the closure is opened a bag opening is
formed between the expandable gusset and said one of the broad face
panels of the bag, to access the bag contents.
[0008] In some embodiments, the body has two opposing gussets
between the broad face panels on opposite ends of the bag, the bag
closure being disposed adjacent one of the gussets. The opposing
gussets may be disposed at top and bottom ends of the bag, for
example, with the bag constructed to rest on its bottom end when
filled. Or the bag may be constructed to rest on a bottom end when
filled, with the two opposing gussets disposed along opposite
vertical sides of the bag, as another example.
[0009] In some preferred cases, the gusset and closure are disposed
at a top end of the bag with the bag standing on its bottom end. In
other preferred cases, the gusset and closure are disposed along a
vertical side edge of the bag with the bag standing on its bottom
end.
[0010] In preferred constructions, the bag closure comprises a
mechanical touch fastener. In some cases, other closure
technologies may be employed, however, such as adhesives. The
presently preferred bag closure has elongated, mating bands of
hooks, hook-engageable fibers, and a unitary strip-form base along
which the mating bands extend in parallel. The base may define a
frangible burst membrane between the mating bands, with the
membrane arranged to be breached to gain initial access to the bag
contents. For some applications, the burst membrane is disposed
inboard of the mating bands. To form an advantageous anti-peel
flap, for example, one longitudinal side of the closure may be
attached to the bag body only outboard of the mating bands. That
one longitudinal side of the closure may be disposed adjacent the
outer broad face panel of the bag, with an opposite longitudinal
side of the closure being secured to the gusset.
[0011] According to another aspect of the invention, a open bag
suitable for filling with contents and sealing after filling is
provided. The bag includes a body having an open end, two opposing,
broad face panels defining a volume therebetween for holding a
quantity of contents, and a flap attached to one of the broad face
panels along the open end, the flap having an inwardly-facing fold
for forming an expandable gusset between the broad face panels
after the open end is sealed. The bag also includes a reclosable
bag closure secured to a free edge of the flap and defining one
side of a fill opening at the open end of the bag.
[0012] In some embodiments, the bag closure comprises two separate
closure strips. One of the strips is secured to the free edge of
the flap, and the other of the strips is secured to a free edge of
an opposing one of the face panels, the two strips together forming
an overlapping touch closure and defining the fill opening
therebetween.
[0013] In some cases the bag body includes two opposing weld
flanges outboard of the bag closure and exposed to be sealed
together after filling. One of the weld flanges extends along the
free edge of the flap and the other weld flange extends along a
free edge of one of the face panels. The bag body can be provided
with a frangible tear line along an inboard edge of at least one of
the weld flanges, for tearing the weld flanges from the bag to
access the contents after filling, for example.
[0014] For some applications, the bag also has a wicket extension
along a free edge of one of the face panels outboard of the
closure, the wicket extension defining at least one hole
therethrough.
[0015] In some embodiments, the bag closure comprises a unitary,
folded strip carrying opposing bands of mating touch fastener
elements on a front face thereof, a back face of the folded closure
strip defining said one of the fill opening.
[0016] The flap extends between sealed edges of the bag in some
applications, to form a full-length gusset. The bag closure may
also extend between the sealed edges of the bag.
[0017] The bag body also forms an expandable gusset on a side of
the bag opposite the flap and bag closure, in some embodiments. In
some cases, the bag is constructed to rest on a bottom end thereof
when filled, with the flap and closure disposed at a top end of the
bag. In other cases, the bag is constructed to rest on a bottom end
thereof when filled, with the flap and closure disposed along a
vertical side edge of the bag with the bag standing on its bottom
end.
[0018] According to another aspect of the invention, a method of
forming fillable, reclosable bags is provided. The method includes
attaching a bag closure strip along one longitudinal edge of a
length of bag film, and forming from at least the length of bag
film a bag having an open end, two broad, opposing faces and a flap
with an inwardly-extending fold. The flap is attached to an edge of
one of the broad faces along the open end and extending between
sealed edges of the bag, with the open end of the bag defining a
fill opening between the closure strip and the other of the broad
faces of the bag.
[0019] In some embodiments, the closure strip comprises an
elongated strip-form base with two spaced-apart, parallel, mating
bands of fastener elements disposed on a common face of the base.
The base is folded along its length between the bands of fastener
elements to maintain the fastener elements in engagement while the
bag is being formed. One of the mating bands of fastener elements
may include hooks, for example, with the other of the mating bands
of fastener elements including hook-engageable fibers. In some
cases, mutually engaging arrays of headed projections may be
employed for the two bands of fastener elements. The band with
fibers may include a non-woven web of fiber.
In some cases, forming the bag includes folding the length of bag
film to form both broad face panels and the flap.
[0020] Preferably, the bag is formed after the closure strip is
attached to the bag film. However, the closure strip may
alternatively be attached after or during bag formation.
In some preferred constructions, the closure strip extends across
the bag between the sealed edges of the bag.
[0021] Forming the bag includes, in some embodiments, cutting the
length of film and the bag closure strip to selected lengths after
the bag closure strip is attached, and sealing cut ends of the film
and closure strip to form the sealed edges of the bag.
[0022] According to another aspect of the invention, a method of
filling and sealing a reclosable bag is provided. The method
includes providing a bag with a body having an open end, two
opposing, broad face panels defining a volume therebetween for
holding a quantity of contents, and a flap attached to one of the
broad face panels along the open end, the flap having an
inwardly-facing fold for forming an expandable gusset between the
broad face panels after the open end is sealed, and a reclosable
bag closure secured to a free edge of the flap and having an
exposed side defining one side of a fill opening at the open end of
the bag; filling the bag with contents through the fill opening;
and sealing the exposed side of the closure strip to the other of
the broad face panels of the bag, to permanently close the fill
opening.
[0023] According to yet another aspect of the invention, a method
of forming, filling and sealing reclosable bags is provided. The
method includes attaching a bag closure strip along one
longitudinal edge of a length of bag film; forming from the length
of bag film a bag having, two broad, opposing faces and an
expandable gusset between the broad faces adjacent the closure
strip; filling the bag with a quantity of contents; and forming a
seal along an edge of the bag between the broad faces and crossing
the closure strip at one end of the expandable gusset, to seal the
filled bag. This method is preferably performed in a vertical
orientation.
[0024] The closure strip is preferably constructed to be folded
along a region between the bands of fastener elements and loops to
place these bands in releasable engagement. Preferably, the
fastener elements are integrally molded with resin of the
substrate.
[0025] In some embodiments, the loop strip comprises a non-woven
web of entangled fibers forming the loops and having a basis weight
of less than about 4 ounces per square yard (preferably, less than
about 2 ounces per square yard). In some cases, the non-woven web
comprises a needled web in a stretched condition.
[0026] In some presently preferred embodiments, the substrate
defines a groove extending longitudinally along the length of the
closure strip between the band of loops and the band of fastener
elements. This groove is preferably lengthwise continuous and
defined by molded surfaces in the front face of the substrate.
[0027] The back face of the substrate is preferably void of
fastener elements and loops, for permanently adhering the substrate
to the sides of the bag. Regions of the back face may be covered
with a layer of adhesive for permanently attaching the closure
strip to opposite sides of a bag, or comprise exposed resin of the
substrate, for permanently welding the closure strip to opposite
sides of a bag formed of a compatible material.
[0028] In some embodiments of the bag, the closure strip of the bag
includes a peelable adhesive seal for resealing the bag after
initial opening. In some cases, this peelable seal also functions
to secure the open end of the bag against inadvertent opening.
[0029] In some embodiments, the substrate of the closure strip is
permanently affixed to the side wall of the bag body with adhesive.
In some other embodiments, the substrate of the closure strip is
welded to the side walls of the bag body. The substrate of the
closure strip and the side walls of the bag body may both be formed
of polyethylene, for instance.
[0030] The bag of the invention is constructed both for ready
reclosure and for expansion, obtaining many of the benefits of
expandable gusset bags (such as the ability to stand unsupported
during storage and display, and to adapt to various fill levels)
while also providing for convenient (in some cases, one-hand)
reclosure. The mating closure strip bands can be made relatively
wide, for easy alignment despite the conformance of the adjacent,
expandable gusset. The closure can be placed inside the bag,
attached directly to the expansion gusset panel, without requiring
additional flaps. The closure can incorporate hook and loop
engagement to provide necessary ventilation for some applications.
Such hook and loop closures are also able to accommodate a fair
amount of dirt or debris without losing their function as closures,
making bags of this construction particularly applicable for
containing granular or powder substances. In addition, the natural
porosity of hook and loop closures can provide some degree of
filtering of airborne dust. Such a ventilated closure can be
particularly desirable in cargo containers of airplanes in order to
accommodate pressure changes, and, by its venting action, may help
to avoid moisture buildup to keep produce and other such items
fresh. The closure can be readily provided with a central burst
membrane to maintain an air-tight seal until the bag is initially
opened.
[0031] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0032] FIG. 1 is a side view of an empty, open bag.
[0033] FIG. 2 is a cross-sectional view of the bag, taken along
line 2-2 in FIG. 1.
[0034] FIG. 3 shows the bag after filling and sealing.
[0035] FIG. 4 shows the bag after initial opening.
[0036] FIG. 5 shows such a bag after reclosing, and filled to a
greater extent.
[0037] FIG. 6 is an enlarged perspective view of the closure strip,
laid flat.
[0038] FIG. 7 is a perspective view of a filled, sealed bag with a
side closure.
[0039] FIG. 8 is a cross-sectional view, taken along line 8-8 in
FIG. 7.
[0040] FIG. 9 shows the bag of FIG. 7 after initial opening.
[0041] FIG. 10 illustrates pouring contents of the bag of FIG. 7
through the open side closure.
[0042] FIG. 11 shows a bag with an upper expansion gusset that
extends over one upper edge of the bag.
[0043] FIG. 12 illustrates a method and apparatus for forming
bags.
[0044] FIGS. 13-15 are cross-sectional views, taken along lines
13-13, 14-14 and 15-15, respectively, in FIG. 12.
[0045] FIG. 16 is a cross-sectional view of a folded bag closure
strip.
[0046] FIG. 17 illustrates a method and apparatus for filling and
sealing bags.
[0047] FIG. 18 is a cut-away view through an open, gusseted end of
a bag having a two-part closure and a wicket extension.
[0048] FIG. 19 shows a vertical form, fill and seal method and
apparatus.
[0049] FIG. 20 is a cross-sectional view, taken along line 20-20 in
FIG. 19.
[0050] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0051] The disposable, reclosable bag 10 of FIG. 1 has two broad
face panels (front panel 12 is fully visible in this view, with
only the upper edge portion of rear panel 16 in view) formed of a
single, folded sheet of polyethylene film sealed along side edges
14. Bag 10 is suitable for packaging bulk granular or powdered
products, such as consumable foodstuffs, animal feed, fertilizers,
cleaners and the like, for retail sale.
[0052] Referring also to FIG. 2, bag 10 is formed to have a bottom
gusset 18 folded inwardly from the bottom edges of front and rear
panels 12, 16 and extending across the full length of the bag
between side seals 14. The upper edge of front face 12 is folded
over twice to form an inwardly extending top gusset 20. Thus, in
this embodiment, a single continuous sheet of bag film is
longitudinally folded along five parallel lines corresponding to
corners 22, 24, 26, 28 and 30. To help maintain the sharpness of
folds 22, 26 and 28, these folds are creased and may even be set by
thermal sealing or other means. Gusset folds 24 and 30 are not
creased in this example, but can be to enable pre-made bags to be
folded flat.
[0053] A reclosable closure strip 32 is attached along the free
edge of upper gusset flap 20, such as by continuous thermal welds
along two spaced apart, longitudinal regions 34 and 36. Adhesives
or other attachment means may also be employed. The closure strip
is folded along its center between mating bands of hooks and loops,
with the hooks and loops initially engaged to hold the closure in
its folded state before the bag is filled. Thus, a fill opening 38
is defined between the exposed face of closure strip 32 and the
inner surface of back face panel 16. The closure strip and fill
opening 38 extend across the length of the bag between the side
seals, where the closure strip is sealed between the front and back
face panels.
[0054] Once the bag has been filled with desired contents (FIG. 3),
the outer, free edge of closure strip 32 is sealed to back face
panel 16 across the entire length of the bag, forming seal 40 that
seals the bag for storage, shipment and retail display. As the bag
is filled, upper and lower expansion gussets 18 and 20 expand, such
that the central vertical cross-section of the bag has a generally
trapezoidal structure, and the interior volume of the bag has
swelled to accommodate the contents. In some cases (see also FIG.
5, for example), upper gusset 20 expands substantially as much as
does bottom gusset 18, such that front and rear face panels 12 and
16 remain generally vertical and parallel. The expanded bottom
gusset 18 forms a stable base upon which the filled bag may be
readily balanced, and by also expanding upper gusset 20, the side
panels of the bag bow outward with enhanced structural stiffness
along the entire height of the bag, for supporting loads from
above. With finer-grained contents (such as bird seed, for
example), much of the load-supporting ability is provided by the
constrained contents themselves, with the upper and lower gussets
enabling the bag to conform to a more block-like structure under
the pressure of the weight of the contents. This bag structure is
also suitable for containing liquids, although for many such
applications a non-venting closure means will be desired, either by
providing the touch fastener closure with an auxiliary seal or by
employing a cohesive closure. In general, face-type closure means
are preferred for ease of closure with little alignment, but for
some applications some types of rib and groove closures, such as
self-aligning or multi-rib constructions, for example, may also be
employed adjacent a gusset.
[0055] To initially open the bag (FIG. 4), the gusset side of
closure strip 32 and the upper edge of back panel 16 are grasped in
separate hands, and pulled laterally away from each other to burst
through the longitudinal frangible region running along the central
portion of closure strip 32 between the mating fastener bands and
form an access opening 43 along the upper end of the bag between
the two sides of the closure strip.
[0056] Advantageously, bag 10 can be reclosed between uses, such as
for post-sale storage. To reclose the bag, one need only bring the
exposed faces of closure strip 32 back into facial contact to
engage the mating fastener bands. Although it might be expected
that the tension in adjacent gusset 20 and the resulting
non-parallelism of the two separated sides of the closure strip
would make reclosure difficult, we have found that with a facial
contact closure the two sides of the closure can be readily brought
into useful engagement because only very minimal alignment and
contact pressure is required. The bag may be reclosed and reopened
a fair number of times to regain access to the bag contents.
Furthermore, with hook-and-loop closure technology the once-opened
closure provides an integral air and gas vent, such as is known to
be useful for vegetables and certain other perishable bag
contents.
[0057] By sending one side of closure strip 32 only along an outer
edge region 40, the lower width of the closed closure strip is able
to flex away from the adjacent side 16 of the bag, as shown in FIG.
5. The flexibility of the thin resin base of the closure strip 32
also enhances its ability to align the mated fastener bands with
the direction of any separating load applied to the closure 32 by
tension in the adjacent gusset 20, thus tending to develop shear
loads across the mated fastener bands rather than peel forces that
would more readily lead to inadvertent opening at higher fill
levels.
[0058] Referring now to FIG. 6, lengthwise-continuous closure strip
32 consists of a thin, sheet-form substrate 42 (of polyethylene,
for example) with lengthwise-continuous, parallel bands 44 and 46
of loops and fastener elements, respectively, on its front face 48.
Bands 44 and 46 are equally spaced from a central groove 50 of the
closure strip, such that when the strip is folded longitudinally at
groove 50 to cover front face 48, the fastener elements of band 46
engage and retain the loops of band 44 to form a releasable
fastening. Preferably, the thickness of the substrate of the
closure strip is about the same as the thickness of the material of
the bag body, in the range of 0.002 to 0.005 inch. The fastener
elements 52 of band 46 are integrally molded with and extend from
front face 48. In this embodiment, these fastener elements are in
the form of J-hooks that extend, in rows, along the length of the
closure strip. Some of the J-hooks face in opposite directions
along the strip. Other fastener element shapes may also be
employed, including those that overhang the substrate 42 in a
widthwise direction. A suitable fastener element shape is the CFM29
hook shape (of about 0.015 inch in height), available in various
products sold by Velcro USA in Manchester, N.H.
[0059] Band 44 of loops consists of a preformed, non-woven web of
polymer fibers, which may include a stabilizing binder, and which
are bonded to front face 48 of substrate 42 at various points
across the width and length of the web. Suitable loop materials
include those disclosed in U.S. Pat. Nos. 6,342,285 and 6,329,016,
the entire disclosures of which are hereby incorporated by
reference as if fully set forth. Other useful loop materials
include some low cost knits, such as ACRI Industrial Termofijado
Knit Loop 4211A99999, available from Tybor S.A. of Girona,
Spain.
[0060] Closure strip 32 may be produced by the method disclosed in
U.S. Pat. No. 6,202,260, and may incorporate other features
disclosed in said patent, the entire disclosure of which is also
hereby incorporated by reference as if fully set forth. Some
suitable methods also employ features of the nip-molding and
in-situ laminating concepts disclosed in U.S. Pat. Nos. 4,794,028
and 5,260,015, the details of both of which are also incorporated
herein by reference.
[0061] Closure strip 32 has an overall width of about 2.5 inches
(64 millimeters) and a nominal thickness of about 0.004 inch (0.1
millimeter). Loop and hook bands 44, 46 each have a width of about
0.75 inch (19 millimeters). In another preferred embodiment they
have widths of about 0.5 inch (12.5 millimeters), as selected for
desired peel resistance. Groove 50 is 0.002 inch (0.05 millimeter)
deep and extends over a width of about 0.125 inch (3.2 millimeter).
Thus, at groove 50 the closure has a reduced thickness of only
about 0.002 inch (0.05 millimeter). On either side of groove 50,
tear-limiting ribs 52 rise another 0.002 inch (0.05 millimeter)
from the nominal surface of the closure base to resist propagation
of tears from groove 50 into either of the fastener bands.
Unitarily molded rip-stop features (not shown) may also be included
on either side of groove 514 throughout the area of the closure
separating the hook and loop bands to help resist tear propagation.
The remaining width of the closure strip forms a flange 54 outboard
of the band 44 of loops, and a narrower flange 56 outboard the band
46 of fastener elements, for welding or otherwise attaching the
closure strip to the bag material.
[0062] Although the illustrated, preferred embodiments employ
hook-and-loop fastening means, other face-contact closures that do
not require precise feature alignment are also suitable, such as
peelable adhesives, inter-engaging arrays of mushroom-type
structures that are engageable in several relative positions, and
other similar closure means.
[0063] Referring next to FIGS. 7-10, another bag 60 has two
opposing side expansion gussets 62 (one hidden from view) and a
bottom expansion gusset. Bags of such overall structure may be
formed by any of a number of known methods, such as by welding
together individual panels or groups of panels along various side,
top and/or bottom edge seals. The illustrated bag has a vertical
side seal 64 joining one of the side gussets 62 to face panel 66.
Extending from the upper edge 68 of bag 60 only partially along
seam 64 is a reclosable closure strip 32 incorporated into seam 64.
Along the length of closure strip 32, the adjacent side gusset 62
is sealed to one outer side of the folded closure strip, with face
panel 66 sealed to the other outer side of the folded closure strip
(see FIG. 8). In this case, both sides of the closure strip are
secured by welds over a relatively wide width behind the fastener
bands. One end of the closure strip is sealed at the upper edge 68
of the bag, and the other end 70 of the closure strip is sealed
within side seal 64, such that the filled bag is initially sealed
for transport and retail display.
[0064] After sale, the closure strip can be pulled open, as shown
in FIG. 9, to burst through the inner membrane of the closure strip
and open the bag. Once open, the location of the closure strip
along the upper vertical edge of the bag is useful for pouring out
the contents of the bag in desired amounts. The upper corner 72 of
the opposing side wall gusset forms a convenient handle for
inserting one or more fingers to help lift and tilt the bag for
pouring, with perhaps another hand grasping the bottom gusset panel
edge 74. The weight of the product during pouring can act to expand
the side gusset to minimize trapping product behind the gusset.
After use, the user need only squeeze the side opening of the bag
closed to re-engage closure 32 for post-use storage. As in the
embodiment of FIGS. 1-5, the closure is relatively easy to
manipulate and re-engage despite the existence of the adjacent
expansion gusset.
[0065] Referring now to FIG. 11, bag 80 is equipped with a top
expansion gusset 82 that extends from upper corner 28 of face panel
12 over the upper edge of face panel 16, and is secured to the
outer face of the bag as shown. In this instance, the reclosable
closure 84 is in the form of two separate strips, one carrying a
band of hooks and the other a mating band of loops, such that the
closure itself performs no pre-entry seal function. Instead, upper
gusset 82 is secured to the upper edge of face panel 16 by a
reclosable, pressure-sensitive seal 86 to help preserve content
freshness even after the initial opening of the bag.
[0066] Referring now to FIG. 12, bags 10 are formed from a
continuous tube 102 of bag film from roll 100. Film 102 is
pre-folded to have two longitudinal, folded gussets. Alternatively,
the bag-forming process can begin with a flat sheet of bag film
that is then folded around a V-board with side gusseters. One edge
of the tube, adjacent one of the two gussets, is slit by blade 104
to form a slit tube (FIG. 13). Next, a continuous closure strip 32
is introduced into the slit around angled bar 106 (FIG. 14), with
the longer side of the strip aligned with the outer edge 108 of the
tube and the shorter side of the strip aligned with the inner edge
110 of the tube adjacent the gusset. Next, the closure strip 32 and
slit tube 102 are passed between two nip rollers 112 (only one
shown) to maintain alignment of the bag film and closure strip
until sealing. The closure strip and bag film are then passed
through a sealing station 114 where a stationary anvil 116 slides
along the adjacent gusset, providing a support surface for heated
sealing shoe 118. Shoe 118 engages the outer surface of the bag
film opposite the closure strip along two parallel regions. Heat
from the shoe is conducted through the bag film and closure strip
to heat seal the back side of the closure strip to the layer of bag
film against anvil 116, to form permanent seals 120 that secure one
side of the closure strip to the bag film, with the other side of
the closure strip remaining unattached to the outer edge of the bag
film tube.
[0067] Referring also to FIG. 16, longitudinal zones of closure 32
are coated with an anti-weld coating 122, such as a flexographic
overprint that functions to resist sealing adjacent surfaces
together in such coated zones as the closure strip and bag film
pass through sealing station 114. Suitable coatings include Matte
Imprintable Overprint No. AWX5-92105-401, available from
Arcargraphics of West Chicago, Ill. The coated anti-weld zones may
be 1/8 inch to 3/16 inch (3 to 5 millimeters) in width, with a
nominal coating thickness of 0.001 inch (0.025 millimeter), for
example.
[0068] Still referring to FIG. 12, the closure strip and bag film
next pass between an opposing pair of transverse sealing bars 124
(again, only one is shown) that repeatedly come together to seal
the bag film together under heat and pressure to form transverse
seals 126 connecting adjacent bags 128. The series of connected
bags is then spooled on roll 130 for later filling and sealing.
Alternatively, sealing bars 124 may be adapted to both seal the bag
film and separate the tube into individual bags that can be stacked
or wicketed. Also, instead of spooling the bags, the series of
connected bags can immediately enter filling and sealing stations
to produce individual, filled bags.
[0069] Referring now to FIG. 17, a roll 130 of seriatim bags is
unspooled into a filling and sealing machine 132. The bag film and
attached closure strip are severed within each transverse seal 126
by cutting bar 134 to separate the individual bags 128. The bags
are each held by clamps 136 that move along track 138 to transport
the empty bags to filling station 140, where they are filled with a
selected quantity of contents dispensed through chute 142. As they
approach the filling station, the distance between the two clamps
136 holding each bag is reduced to help enable the opening of the
upper end of the bag for filling. During filling, the lower end of
the filling bag is allowed to rest at least partially on an indexed
conveyer 144. Next, the filled bag moves on conveyer 144 to a top
sealing station 146 where the two clamps 136 holding the upper
corners of the bag within the side seals 126 are moved apart from
each other to apply tension along the bag opening as a heated,
horizontal sealing bar 148 comes down and engages the upper edges
of the closure strip and bag film to seal the bag.
[0070] FIG. 18 shows a closure structure for bags that are to be
filled through the closure, rather than between the closure and bag
film. Closure 150 consists of two separate strips, a hook strip 152
and a loop strip 154. The two strips may be produced as a single
closure strip and subsequently split into the two strips, if
desired. Hook strip 152 is bonded to the bag film along its two
edges by heat seals 120. Loop strip 154 is only attached along its
outer edge by a single continuous heat seal 120, leaving the edge
of the loop strip facing into the bag tube free as shown. The hook
and loop strips are aligned with each other such that their mating
arrays of loops and hooks will engage under light pressure to
reclose the bags formed of this precursor bag film and closure
assembly. The outer edge the bag film has a wicket extension 156 of
perhaps 1.5 to 2.0 inches (37 to 50 millimeters) in width and
joined to the rest of the bag film along a series of perforations
158. Extension 156 defines a series of through holes 160 for
engagement by wickets. In some cases, holes 160 are equally spaced
along the bag film tube for engagement by a tractor wheel during
processing. Perforations 158 enable the extension and its wicket
holes to be severed from the rest of the bag film after processing.
Adjacent extension 156 is a weld flange 162 outboard of closure 150
and of a width sufficient for sealing the two outer edges of the
bag film together. Another series 164 of perforations or a weakened
tear line may be included to enable the sealed weld flanges 162 to
be torn from the rest of the bag film to access closure 152 after
retail sale, for initial opening, so as to provide the bag with a
tamper-evident tear strip.
[0071] FIGS. 19 and 20 illustrate a vertical form-and-fill
operation in which a folded continuous length of closure strip 32
is introduced between the facing edges of bag film 166 advanced
about a forming collar 168 onto a fill tube 170. As the closure
strip and bag film edges are sealed between seal bars 172, two
gusset wheels 174 direct the bag film into two opposing grooves 176
in opposite sides of the fill tube, one of the grooves and gusset
wheels located adjacent the seal flange containing the closure
strip. Immediately below the lower end 178 of the fill tube, twin
lateral sealing bars 180 come together at fixed time/length
intervals to seal across, and cut through, the bag film and closure
strip to form individual, sealed, filled bags. As bars 180 come
together they secure the gusset folds created by wheels 174 at the
top of a filled bag below bars 180, and secure the bottom ends of
the gusset folds of the next bag to be filled, above bars 180. In
some cases, bars 180 form two lateral seals and incorporate a
cutting bar to cut through the bag film between the seals.
[0072] Wicketed, gusseted bags having the reclosable closure as
shown in FIG. 18 can also be filled in a horizontal filling process
(not shown), such as one in which the contents are inserted through
a spring-loaded duck bill insertion tube. Such bags can be received
as a wicketed stack as known, for example, in the packaging of
bread and the like. The top bag of the stack is air inflated, and
the force of over-inserting the product rips the bag from the
wicket. In some cases, the product may be inserted without tearing
the bag from the wicket, the closure can be closed and the weld
flanges 162 sealed together to seal the bag while the bag is yet on
the wicket. Then, the wicket extension 156 can be torn from the bag
along line 158, or can be slit from the bag during sealing. Such a
filling method and bag structure is useful for packaging frozen
food items, such as fish sticks and waffles and the like, as the
hook and loop bag closure functions well as a repeat closure under
very cold conditions as are found in freezers (where some adhesives
exhibit some deterioration of function), and also continue to close
through crumbs and other debris generated by repeated access to
such contents.
[0073] The gusseted, reclosable bags discussed above can also be
employed for packaging items in trays, such as coffee cakes and the
like that are commonly packaged in boxes. The width of the bag
between the side seals should be sufficient to enable the side
seals to be displaced toward one another as the opening is extended
to full height over a width sufficient to receive the product.
After filling and sealing, the end gussets of such bags help to
provide a box-like appearance for retail display. The aluminum
trays in which such cakes are baked could have extended side panels
to enable such packages to be stacked without damaging the goods,
for example.
[0074] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *