U.S. patent application number 14/066203 was filed with the patent office on 2014-05-01 for bag with support brace.
The applicant listed for this patent is Peel Plastic Products Limited. Invention is credited to Michael Reid Martin.
Application Number | 20140119676 14/066203 |
Document ID | / |
Family ID | 50547268 |
Filed Date | 2014-05-01 |
United States Patent
Application |
20140119676 |
Kind Code |
A1 |
Martin; Michael Reid |
May 1, 2014 |
BAG WITH SUPPORT BRACE
Abstract
A bag formed of plastic film material has first and second side
panels with a margin portion at a rear edge of the first side panel
joining a margin portion at a rear edge of the second side panel at
a rear seam. The rear seam along at least a part of its length is
braced by a solid elongate brace of plastic material which is
either fixed mechanically to the panels or is thermally welded to
them.
Inventors: |
Martin; Michael Reid;
(Toronto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Peel Plastic Products Limited |
Brampton |
|
CA |
|
|
Family ID: |
50547268 |
Appl. No.: |
14/066203 |
Filed: |
October 29, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61719831 |
Oct 29, 2012 |
|
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Current U.S.
Class: |
383/7 ; 383/119;
383/17; 383/66 |
Current CPC
Class: |
B65D 75/56 20130101;
B65D 75/5883 20130101 |
Class at
Publication: |
383/7 ; 383/119;
383/17; 383/66 |
International
Class: |
B65D 33/02 20060101
B65D033/02 |
Claims
1. A bag formed of plastic film material, the bag having a first
side panel, a second side panel, a margin portion at a rear edge of
the first side panel joining a margin portion at a rear edge of the
second side panel at a rear seam, a brace fixed to the rear seam
along at least a part of its length .the brace being an elongate
solid plastic member.
2. A bag as claimed in claim 1, the rear seam being part of a
complex of seams defining an interior storage space of the bag.
3. A bag as claimed in claim 1, the rear seam part being at least
part of a handle, the bag further comprising a rear gusset
extending between respective side seams, the respective side seams
formed between the rear gusset and the first and second side
panels, the first and second side seams being part of a complex of
seams defining an interior storage space of the bag, the handle
being on the distal side of the rear gusset from the interior
storage space.
4. A bag as claimed in claim 1, the brace attached to the rear seam
by rivets.
5. A bag as claimed in claim 1, the plastic member positioned in an
elongate pocket formed between the first and second panels at the
rear seam.
6. A bag as claimed in claim 1, the plastic member fixed between
the first and second side panels at the rear seam.
7. A bag as claimed in claim 1, the plastic member positioned
against the rear seam on one side of the bag, and a second plastic
member positioned against the rear seam on the other side of the
bag.
8. A bag as claimed in claim 7, further comprising a third plastic
member fixed between the first and second side panels at the rear
seam.
9. A bag as claimed in claim 7, the rods being lamellar and joined
by a spine portion to form a channel structure embracing a rear
part of the rear seam.
10. A bag as claimed in claim 1, the plastic member having a
cross-section which, along at least a part of its length, is one of
round, rectangular, regular polygon, lamellar and star.
11. A bag as claimed in claim 1, the plastic member attached to the
rear seam by adhesive.
12. A bag as claimed in claim 9, the channel structure attached to
the sides of the rear seam by the rear seam being pinched between
the lamellar rods.
13. A bag as claimed in claim 1, the cross-sectional shape of the
plastic member varying along its length.
14. A bag as claimed in claim 1, the plastic member fixed to a part
of the rear seam, another plastic member fixed to another part of
the rear seam, the rods integral with an intermediate handle part
extending between the two rods and spaced from a contents storage
part of the bag.
15. A bag as claimed in claim 14, the brace bowed or angled
outwardly s to present a space between the handle part and the
contents storage part of the bag.
16. A bag as claimed in claim 1, further comprising an openable and
closeable pouring fixture at the front of the bag.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a bag having a support brace.
DESCRIPTION OF RELATED ART
[0002] Plastic bags are a ubiquitous and highly practical mode of
carrying things and there is a whole panoply of shapes and
structures of such bags depending on the particular function of the
bag. Many bags have handles of some kind or other. These may be
merely formations in the material of the bag itself or may include
additional elements which are attached to the main carcass of the
bag and which provide added strength and convenience.
[0003] Of particular interest from the viewpoint of reducing
packaging materials are plastic bags that might replace in the
marketplace freestanding, relatively thick-walled plastic jugs.
Such a replacement is desirable for many reasons. Firstly, the
volume of plastic material required in thick-walled plastic jugs is
generally much higher in comparison with plastic bags configured to
function as jugs. Secondly, placing of graphic materials is much
easier on plastic bags where simple printing directly onto a
paper-like plastic sheet can be implemented. Conventionally,
printing is done on to a ply of the plastic sheet material, a
typical ply material being polyester which readily accepts industry
standard printing inks. This is in comparison with stiff-walled
jugs which generally have some contour in the walls making it
difficult for a print head to seat against anything but a very
small wall area. This may mandate a relatively expensive process
step of attaching labels to the jugs. Finally, prior to filling,
thick-walled jugs being stored or shipped take considerable space
in comparison with a compact stack of flat plastic bags.
[0004] The structure of a handled bag that is to function as a jug
should have the strength to hold granular or fluid contents. It
should also have a form enabling it to be gripped in one hand,
moved from a standing into a pouring position and back again, and,
ideally, for the pouring position to be retained as substantially
all the contents of the bag are poured from a spout or functionally
similar devices. Throughout the use cycle, the bag should
substantially retain a jug form and function until the contents
have been emptied. Finally, such a structure must be easy to
manufacture.
[0005] While bags with handles are known that can provide a
substitute for jugs made of more rigid materials, further
improvements are possible to improve the performance and
manufacturability of such bags. Limitations and disadvantages of
conventional and traditional approaches to bag-as-jug designs and
manufacture thereof will become apparent to one of ordinary skill
in the art through comparison of such bags with the present
invention.
SUMMARY OF THE INVENTION
[0006] According to one aspect of the invention, there is provided
a bag formed of plastic film material, the bag having a first side
panel, a second side panel, a margin portion at a rear edge of the
first side panel joining a margin portion at a rear edge of the
second side panel at a rear seam, and a brace fixed to the rear
seam along at least a part of its length, the brace being a solid
plastic member. The plastic member can have a cross-sectional shape
which is any of regular polygonal, circular, square, rectangular,
elliptic, lamellar, star-shaped or irregular.
[0007] The rear seam can be part of a complex of seams and panels
defining an interior storage space of the bag. Alternatively, the
rear seam can be part of a handle, the bag further comprising a
rear gusset extending between respective side seams, the respective
side seams formed between the rear gusset and the first and second
side panels, the first and second side seams being part of a
complex of seams and panels defining an interior storage space of
the bag, the handle being on the distal side of the rear gusset
from the interior storage space.
[0008] The plastic member can be positioned in an elongate pocket
formed between the first and second panels at the rear seam.
Alternatively, the plastic member can be fixed between the first
and second side panels at the rear seam. Alternatively, the plastic
member can be fixed against one side of the rear seam. The rear
seam can be sandwiched between the plastic member fixed to the rear
seam on one side of the bag and a second plastic member fixed to
the rear seam on the other side of the bag. The rear seam can
include a first plastic member fixed between the side panels at the
rear seam, a second plastic member fixed to the rear seam on one
side of the bag, and a third plastic member fixed to the rear seam
on the other side of the bag. In the two-plastic member and
three-plastic member structures, the plastic members can be
lamellar and can be joined by a spine portion to form a channel
structure embracing a rear part of the rear seam.
[0009] The or each plastic member can be attached to the rear seam
by rivets or other mechanical fixture device. Alternatively, the
plastic member or members can be fixed to the rear seam by
adhesive. In a further alternative, the plastic member or members
can be fixed to the rear seam by being pinched between elements of
a channel section plastic member.
[0010] The cross-sectional shape of the plastic member can vary
along its length to present a thickened area ergonomically suited
to gripping or to provide enhanced support at selected locations.
The brace can have a first plastic member part fixed to part of the
rear seam, a second plastic member part fixed to another part of
the rear seam and an intermediate plastic member part spaced from
and not fixed to the rear seam whereby to provide a handle part at
the intermediate plastic member part. Such intermediate plastic
member part can be bowed or angled outwardly to present a space
between the handle part and the contents storage part of the
bag.
[0011] The bag can further comprise an openable and closeable
pouring fixture at the front of the bag.
[0012] According to another aspect of the invention, there is
provided a bag formed of plastic film material, the bag having a
first side panel, a second side panel, a margin portion at a rear
edge of the first side panel joining a margin portion at a rear
edge of the second side panel at a rear seam, the rear seam along a
first part of its length braced by a solid elongate thickened
region derived from a starter rod of thermoplastic material welded
to the rear seam.
[0013] The rear seam can be part of a complex of seams and panels
defining an interior storage space of the bag. Alternatively, the
rear seam can be part of a handle, the bag further comprising a
rear gusset extending between respective side seams between the
rear gusset and the first and second side panels, the first and
second side seams being part of a complex of seams and panels
defining an interior storage space of the bag, the handle being on
the distal side of the rear gusset from the interior storage
space.
[0014] The thickened region can be derived from first and second
starter rods thermally welded to opposite sides of the rear seam.
The thickened region can alternatively be derived from a trio of
starter rods, one welded between the side panels at the rear seam
and the other two welded to opposite sides of the rear seam. The or
each starter rod can have an initial cross-sectional shape which is
any of round, square, rectangular, elliptic, star-shaped, regular
polygonal, lamellar and irregular, whereby to obtain a desired
cross-sectional profile of the thickened region following thermal
welding. The starter rod can have varying cross-sectional shape and
size along its length whereby to result in a thickened region at
the rear seam which varies along its length.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For simplicity and clarity of illustration, elements
illustrated in the following figures are not drawn to a common
scale. For example, the dimensions of some of the elements are
exaggerated relative to other elements for clarity. Advantages,
features and characteristics of the present invention, as well as
methods, operation and functions of related elements of structure,
and the combinations of parts and economies of manufacture, will
become apparent upon consideration of the following description and
claims with reference to the accompanying drawings, all of which
form a part of the specification, wherein like reference numerals
designate corresponding parts in the various figures, and
wherein:
[0016] FIG. 1 is an isometric view of a pouch bag including a
bracing arrangement according to an embodiment of the
invention.
[0017] FIG. 2 is a view from below of the bag of FIG. 1.
[0018] FIG. 3 is a scrap cross-sectional view of a bag with braced
seam according to one embodiment of the invention.
[0019] FIG. 4 is a scrap cross-sectional view of a bag with braced
seam according to another embodiment of the invention.
[0020] FIG. 5 is a scrap cross-sectional view to a larger scale of
a bag with braced seam according to a further embodiment of the
invention.
[0021] FIG. 6 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0022] FIG. 7 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0023] FIG. 8 is an isometric view of a pouch bag including a
bracing arrangement according to another embodiment of the
invention.
[0024] FIG. 9 is a view from below of the bag of FIG. 8.
[0025] FIG. 10 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0026] FIG. 11 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0027] FIG. 12 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0028] FIG. 13 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0029] FIG. 14 is a scrap cross-sectional view of a bag with braced
seam according to a further embodiment of the invention.
[0030] FIG. 15 is a scrap cross-sectional view showing a stage in
the manufacture of a bag with braced seam according to an
embodiment of the invention.
[0031] FIG. 16 is a scrap cross-sectional view showing a braced bag
seam produced by the manufacturing stage illustrated with reference
to FIG. 15.
[0032] FIG. 17 is a scrap cross-sectional view showing a stage in
the manufacture of a bag with braced seam according to another
embodiment of the invention.
[0033] FIG. 18 is a scrap cross-sectional view showing a bag with
braced seam produced by the manufacturing stage illustrated with
reference to FIG. 17.
[0034] FIG. 19 is a scrap cross-sectional view partly in
perspective showing a stage in the manufacture of a bag with braced
seam according to another embodiment of the invention.
[0035] FIG. 20 is a side front view partly in perspective showing a
gusseted bag-with-handle strengthened by a bracing arrangement
according to an embodiment of the invention.
[0036] FIG. 21 is a sectional view on the lines A-A of FIG. 20 when
the bag contains granular or fluid material.
[0037] FIG. 22 is a side view similar to FIG. 21, but showing a bag
with braced seam according to another embodiment of the
invention.
[0038] FIG. 23 is a side view of a bag according to an embodiment
of the invention.
[0039] FIG. 24 is a side view of a bag according to another
embodiment of the invention.
[0040] FIG. 25 shows a series of handle braces prior to stamping,
the braces being for the bag shown in FIG. 23.
[0041] FIG. 26 is a section view on the line B-B of FIG. 25.
DETAILED DESCRIPTION OF THE INVENTION INCLUDING THE PRESENTLY
PREFERRED EMBODIMENTS
[0042] Referring to FIG. 1, there is shown a pouch bag 10 formed of
plastic sheet material having side panels 12, 14. The side panels
are joined at the rear and front of the bag by respective
thermoplastic welded seams 16, 18. At the bottom of the bag, a
gusset 20 extends between the two side panels 12, 14 and is welded
to them. Attached to the rear seam 16 is a generally vertically
extending brace 22. The bag may be orientated so that the brace 22
is located atop the bag to provide a rudimentary carrying handle.
Alternatively, for use when the bag has a vertical orientation as
shown in FIG. 1, the brace 22 assists upright storage by providing
a backbone for the bag 10 when set down on a surface such as a
table top so that materials contained in the bag are not spilled.
The brace 22 also provides a rudimentary pouring handle that is
more easily gripped than if the bag alone is gripped so as to
enable pouring.
[0043] The bag of FIG. 1 is particularly adapted for use as a
pouring bag for containing and storing granular materials and
fluids. Between the front weld 18 and a top welded seam 24 at the
front top corner of the bag 10, a corner is cut as shown at 19 and
a pouring spout/cap combination 26 is partially inserted between
the cut side panels 12, 14. The cut edges at the front top corner
are seam welded to each other and around the outer surface of the
pouring spout device 26. Whereas one form of reclosable pouring
device is shown, alternative forms of reclosable pouring device can
be implemented such as a slide fastener or zip, a Velcro.RTM.
fastener, or, if sealing is not important, by a simple opening
which is cut at the time the container is first used. While a
braced bag has particular value as a pouring bag, the design
principles of the invention may find application in plastic bags
which are not for use in pouring.
[0044] As shown in FIG. 1, the brace 22 is an elongate plastic
element separate from, but attached mechanically to, the main part
of the bag. FIGS. 3 to 7 show several different embodiments of such
a brace and the manner of their attachment to rear seam 16 of the
bag.
[0045] Referring in detail to FIG. 3, the brace 22 is a U-section
plastic strip 28 which is fitted over the rear seam weld 16 after
the weld has been formed. Once in place, the channel section piece
22 is fixed by rivets 30 although other fastening means can be
employed. In the alternative embodiment of FIG. 4, a similar
structural principle is adopted but, instead of a single U-channel
piece, two separate elongate rods or leaves 32 are positioned
against opposite sides of the seam 16 and are then fastened
together.
[0046] In an alternative arrangement illustrated in FIG. 5 to a
larger scale, one wall 34 of a channel-form piece has inwardly
projecting tangs 36 while the other wall 38 has cooperating
inwardly facing, anchoring recesses or apertures 40. The tangs 36
are made sharp enough to penetrate the seam 16 when the two walls
34, 38 of the channel-form piece 28 are pressed together after the
channel piece 28 has been threaded onto the seam 16. After
penetrating the seam 16, the tangs 36 enter and are retained in the
anchor recesses or apertures 40.
[0047] In a further alternative embodiment shown in FIG. 6, a
U-channel brace member 90 is formed with channel walls 34, 38 in
their rest position angled in towards each other. During
post-processing of a bag, the walls 34, 38 are forced apart to
enable positioning of the seam 16 within the channel. In the
deformed position, the walls 34, 38 seek to return to the rest
position, so that the outer ends of the walls apply localized
spring pressure along the length of the seam 16 as to pinch and
clamp the channel brace member 90 to the seam.
[0048] Referring to FIG. 7, a brace member is in the form of a
star-shaped rod 47. The rod is received in a pocket formed between
rear seam sections 16A and 16B. The pocket may be formed in the
course of bag manufacture with the rod 46 subsequently being
threaded along the pocket. Alternatively, the rod is positioned
between the two side panels 12, 14 at the intended site of the rear
seam. The seam, including the seam sections 16A and 16B, is then
formed with the rod in place. The rod 47 may be of any convenient
shape depending on the appearance or other characteristics desired
in terms of a brace of handle. For example, the rod can be made
relatively wide and orientated in the pocket so as to particularly
resist side-to-side bending or front-to-back bending.
[0049] Referring to FIGS. 8 and 9, there is shown a pouch bag 10
similar to the bag of FIGS. 1 and 2. However, instead of a separate
brace, the bag has at its rear seam 16 a brace 23 that is formed as
a generally vertically extending, thickened region of plastic
material. The thickened region brace 23 is obtained by welding a
starter rod 46 of plastic material to the sheet plastic material of
the bag at the site of the rear seam 16. The starter rod 46 can be
welded to the bag side panels in the course of bag manufacture or
can be welded in a post-processing stage after the bag is
essentially fully formed.
[0050] FIGS. 10 to 14 show in cross-section several forms of a bag
brace 23 where the brace is joined to the main part of the bag by
thermoplastic welding so that it becomes an integral part of the
bag. Each of the structures shown in these figures can, however,
alternatively be made using an adhesive to cement elements of the
structure together as an alternative to thermoplastic welding, such
a structure being particularly applicable in cases where a
thermoplastic weld is impossible or difficult to implement. While
the embodiments in these figures show a brace 23 used to strengthen
a rear seam 16, thermoplastic welded braces of the forms shown can
be used for locally strengthening other or additional seams of a
bag as desired.
[0051] FIG. 10 shows an internal brace produced by putting a
starter rod or strip 46 of thermoplastic material between margins
42, 44 of the side panels 12, 14 in the course of bag manufacture,
the margins 12, 14 and the starter rod material then being welded
together at the time the seam weld 16 is made. FIGS. 11 to 14 show
external braces in which starter rods or strips 46 of thermoplastic
material are positioned against the outside of the bag and are then
thermally welded against one or both side panels 12, 14 at the seam
location. Generally, from a manufacturing perspective, external
brace structures are preferred over internal brace structures
because it is difficult to retain a starter rod of thermoplastic
material in a desired registration position with flanking sheet
plastic panels during a heat welding operation.
[0052] Referring in detail to FIG. 10, in the course of
manufacture, the starter rod 46 of thermoplastic material is
sandwiched between the front and back panel margins 42, 44 at the
site of a rear seam 16 and a seam weld is then implemented at the
site. In the course of seam welding, adjacent regions of the panels
12, 14 wrap around and are welded to the rod 46 which is deformed
from its initial shape by the application of temperature and
pressure. The bracing rod 46 may initially be of circular, square,
rectangular, polygonal or other convenient cross-sectional shape.
The rod loses its initial cross-sectional shape during welding, but
remains as a localized thickened region extending down the seam 16
after the thermal welding operation is complete.
[0053] As shown in FIG. 11, a starter rod 46 is alternatively
positioned on the outside of one or both side panels 12, 14. Again,
a localized general thickening is achieved by thermally welding the
rod(s) and the panel edge margin(s) together but, in this instance,
the rod material is on the outside of the weld while the panel
material is on the inside. In a variant of the FIG. 11 embodiment,
a single rod is applied to one panel without a corresponding rod
being applied to the other panel to achieve the localized braced
region. In the embodiment of FIG. 11, rods are welded to each side
of the bag so as to be made integral with the respective side
panels 12, 14 with the thickened region 22 spaced forwardly from
the rear edge of the bag. Alternatively, starter rods 46 are placed
so that they overlap the rear edges of the panels 12, 14.
Consequently, when thermal welding is applied, the fused material
from the rods 46 spreads around the rear edges of the panels 12, 14
as shown in the embodiment of FIG. 12. In the finished structure,
after the thermal weld is implemented, the strengthening plastic
from the starter rod 46 and the material of the side panels 12, 14
will normally be indistinguishable from one another when viewed
with the naked eye. Referring to FIG. 13, an alternative embodiment
of seam brace 22 is shown. Initially, the starter rod 46 is placed
against the margin regions 42, 44 of overlapping panels 12, 14 so
that a part of the margin regions projects beyond the rod. The
overlapping margin regions are then rolled around the starter rod
46 and held in the rolled position as the thermal weld is effected.
Overlaps of each side panel 12, 14 can alternatively be rolled in
opposite directions around two starter rods 46 placed on opposite
sides of the bag before thermal welding is effected as shown by
FIG. 14. It will be appreciated that FIGS. 8 to 14 show the shape
of the starter rod material after the rod 46 has been somewhat
deformed from a more regular cross-section following the
application of welding heat.
[0054] In each of the embodiments of FIGS. 8 to 14, the welds are
effected with a hot press tool in the form of a flat plate 48 as
shown in FIG. 15. Consequently, a brace profile is obtained which
typically has a relatively smoothly varying contour as shown in
FIG. 16, the exact contour depending on the fluidity of the several
plastic elements at the weld location, and the extent to which the
fluid material of each element flows. A hot welding tool 50 of
different configuration is used to shape the thermal weld to a
different cross-sectional shape as shown in FIGS. 17 and 18. Such a
cross-sectional shape may be implemented for mechanical purposes,
for example to render the thickened region less susceptible to
bending in a particular plane. It may alternatively be implemented
for aesthetic purposes. As an alternative to hot plate welding,
especially to generate heat at the centre of a relatively large
piece of plastic which is the case with a starter rod 46 of the
types shown, ultrasonic welding can be applied.
[0055] The material of the starter rod 46 must, in the embodiments
of FIGS. 8 to 14 have at least a surface ply that consists of
thermoplastic material and which faces a thermoplastic sheet or ply
of the bag panels 12, 14 to enable the thermoplastic weld to be
effected. While this does not present a problem with bag panels
that are made of thermoplastic material throughout, most plastic
bags have panels that have an outer ply of polyester or material
having like characteristics. An outer ply of polyester is desirable
because it is amenable to printing using generally available
commercial inks. Also, polyester does not melt when heat is
applied, which means that heat can be transmitted without
difficulty through to a thermoplastic layer at the opposite surface
of a starter rod. To effect a thermoplastic weld between such a
panel/starter rod combination, the panel and the starter rod are
configured to ensure that at least part of the starter rod
thermoplastic surface is brought into contact with another
thermoplastic surface. In the exemplary embodiment of FIG. 19, the
side panels 12, 14 have vias 52 spaced along their rear edge
margins. The starter rods 54, 56 each have a polyester layer 58 and
a polyethylene layer 60. The rods 54, 56 are positioned to cover
the vias 52 so that when a thermoplastic weld is effected, melted
material from a thermoplastic layer 58 of the rod 54 flows down as
shown in FIG. 19 into the vias 52, while thermoplastic material
from the lower starter rod 56 flows up into the vias, with the
flowing material from each side fusing to effect the weld. At the
same time, thermoplastic material of facing plies 62, 64 of the
side panels 12, 14 outside the region of the vias fuses to weld the
side panels to each other.
[0056] A starter rod, as an alternative to being of solid,
homogeneous plastic material, may have other plies or components
which add desired characteristics to the rod material and the bag
to which the resulting brace is applied. For example, as previously
indicated, especially for a starter rod of rectangular or leaf
form, the rod can have a polyester surface layer on the opposite
face from a thermoplastic layer in order that the outwardly facing
surface of the thickened region of the bag will take a conventional
printing ink. Alternatively, or in addition, the starter rod can
include a strength ply made, for example, of nylon.
[0057] As previously mentioned, the thickened region is
advantageously effected at a bag rear seam to provide both a
rudimentary handle function and a bracing function. A bag 10
somewhat different from the pouch bags previously illustrated is
shown in FIGS. 20 to 22. The bag is one of several forms of bag
described and claimed in co-pending U.S. patent application Ser.
No. 13/655,784 which is hereby incorporated by reference in its
entirety. The exemplary form of bag 10 has side panels 12, 14 and a
rear gusset panel 66, with the side panels 12, 14 each having
extensions 68 that are welded together at a handle seam 70. The
combined width of the extensions 68 is greater than the width of
the gusset panel 66, and the extensions are formed with carrying
apertures 72. The bag is shown partially filled and in
cross-section in FIGS. 21 and 22, these views corresponding to the
section line A-A of FIG. 20. As shown in FIG. 21, a brace 22 is
fixed to rear seam 70 which is spaced from the part 74 of the bag
which is to contain fluid or granular materials. Any of the
mechanically attached brace structures described with respect to
the bags of FIGS. 3 to 7 can be adopted in the bag of the form
shown in FIG. 20 and in bags of the form described and claimed in
the aforementioned patent application Ser. No. 13/655,784. In the
embodiment illustrated in FIG. 22, a thickened region 23 is
developed at the seam 70. The thickened region 23 is ergonomically
more easy to use as a handle because of the presence of the
associated apertures and the spacing from the contents chamber 74.
The brace 23 is formed by welding a starter rod at the junction
between the extensions 68. Any of the thickened region brace
structures described in FIGS. 10 to 14 can be adopted in the bag of
the form shown in FIG. 22.
[0058] While it is normally convenient and advantageous to apply a
strengthening brace at the rear seam 16, a strengthening brace can
alternatively be applied at other seam positions where local or
directional strengthening is desired. For example, as shown in the
pouring bag illustrated in FIG. 24, the bag 10 has, in addition to
a rear brace 23, a welded, vertically extending rib 76 at the front
seam 18. Particularly for a bag which may have good upright posture
for most stages of fill, but which shows posture weakness in one
location for a particular fill stage, a supporting rib such as rib
76 can be judiciously located and orientated to tailor support to
mitigate that particular weakness. The shape and size of the rib
can be similarly tailored to overcome a particular posture weakness
or to provide strength at a region of structural weakness. As shown
in FIG. 23, a mechanically fixed brace 22 is shaped to offer
greater ergonomic efficiency particularly tuned for any of carrying
and pouring. The brace has a central part 92 permitting a user to
insert his or her hand and has two wing parts 94 riveted to the
rear seam 16. The shape of the brace 22 lends itself to being
stamped from a layer of sheet plastic as shown by FIG. 25. In a
preferred embodiment, a pair of the braces is located at each side
of the rear seam and riveted together with parts of the rear seam
16 pinched between. As shown by FIG. 26, which is a sectional view
on the line B-B of FIG. 25, the brace material can be stamped while
still malleable so as to form in the cooled member angle elements
96 which add to the stiffness of the handle when the bag is
assembled.
[0059] To obtain a high production rate when manufacturing bags,
processing operations are typically performed on a continuous web
of plastic sheet material. During a production run, the web is fed
continuously under tension from an input end where the web is
unformed to an output end where, essentially, a complete bag has
been produced and is cut from the web leading end. The web is led
past a series of processing stations where processing operations
are performed including, for example, positioning, stamping,
cutting, folding and thermoplastic welding, depending on the stage
of manufacture of the bag.
[0060] An important step in manufacturing the bag is making the
seams. Essentially the parts of the perimeter of each bag panel is
sealed to corresponding margin parts of the perimeter of other
panels, including gusset panels, with one seam being left open to
allow for filling by the customer. In the course of the production
process, if the seams are to be thermally welded, then the bag
parts to be welded must be made of a thermoplastics material or
must have a thermoplastic ply which is brought against another
thermoplastic material or ply in the course of the welding process.
A hot press tool is used to apply heat and pressure to hot melt the
polyethylene. The web may be subjected to several welding steps to
form seams at or near the panel edges.
[0061] In the bag of FIG. 24, the welded brace 23 has a part 86
which is locally thicker than other parts of the brace to make it
more comfortable for gripping by a human hand of normal size. While
the brace of FIG. 24 is shown with the larger cross-section part 86
generally centered along the bag 10 when it is in an upright
aspect, a thicker part or parts can be located at alternative
positions along the brace. For example, such a brace might have
both a hand grip enlarged portion 86 and a relatively sturdier
anchor part (not shown) at the top of the bag to provide additional
anchoring strength for a full bag when it is first tipped over to
initiate pouring.
[0062] The embodiments of the invention illustrated describe pouch
bags which are generally rectangular in side plan. In such a pouch
bag, for efficient use of plastic sheet material and ease of
manufacturability, each of the several panels of the bag is
generally rectangular, with seam welds along the boundaries of each
panel where it joins other panels including some that may be gusset
panels. However, any of the bag panels can have a shape that is
other that rectangular, provided that adjacent panels have
appropriate shapes as needed to make the boundary welds possible.
For example, the front and back panels, which are the major panels
in terms of determining the overall shape of the bag, may have a
generally elliptic or triangular configuration. In addition, bag
volume can be increased by adding a gusset elsewhere than at the
bottom of the bag as shown by the illustrated embodiments or at the
rear of the bag as shown in the FIGS. 20 to 22 embodiments. Gussets
can for example be inserted at the top or front seam locations,
thereby doubling the number of seams at such locations. In each of
the illustrated embodiments, seams are shown as being formed
between two pieces of sheet plastic material which are placed in an
overlapping disposition before a thermoplastic weld is effected. In
plastic bag manufacture, the bag is typically made from a single
web which may be folded at certain positions in such a way that two
pieces of sheet plastic are in overlapping disposition at the fold.
The term seam in this specification encompasses a thermoplastic
weld made at such a fold.
[0063] In each of the embodiments of the invention described, the
bag is formed from sheet plastic material that is at least partly a
heat-sealable thermoplastic material and sealing/welding is
effected by heat sealing. Such materials include, by way of example
and not limitation, polyolefins such as polyethylene and
polypropylene, vinyl polymers, and the like. The materials may be
low-, medium- or high-density polymers and may be single or
multi-layer composite material. Composite laminated materials may
include adhesive layers. Sealing resins such as ethylene vinyl
acetate may be used to improve sealing of certain polymer layers
and the use of such sealing resins may obviate the use of adhesive
tie layers. The invention contemplates the use of thermoplastics
films which are made of or which include, a barrier sheet material
such as, for example, EVOH or a metal layer which provides a
barrier generally preventing the transmission of gases. The
thickness of the film material is selected mainly on the basis of
the intended weight the bag must carry and generally ranges from
about 2 to 20 mils.
[0064] The type of thermoplastic sheet material used will depend on
the purposes to which the bag is to be put, whether it is easy to
handle in manufacturing, whether it can be readily printed upon,
whether it is waterproof, whether it is strong enough to resist
tearing or bulging, etc.
[0065] A particular implementation uses a multi-ply plastic sheet
material including a polyethylene layer which makes effective
thermoplastic welds/bonds and has high strength, and a layer of
polyester which accepts printed indicia very well. In the
manipulation of the web portions, generally polyethylene surfaces
are brought together where two parts of the sheet material have to
be joined so that a bond/weld can be implemented by using
thermoplastic heat sealing techniques rather than adhesive bonding.
Similarly such manipulation is configured so as generally to
present the polyester surfaces outwardly for application of print
indicia. It will be understood however, that whereas thermoplastic
welding of materials such as polyethylene is preferred, a bag
according to this invention can be manufactured with any or all of
the welded seams being substituted by adhesive seams.
[0066] In one example, the sheet plastic material of the bag has a
polyethylene layer 1 to 7 mils thick, an adhesive polymer layer 0.1
to 0.5 mils thick, and a polyester layer 0.5 mils thick, the layers
being coextruded or adhesively laminated. The layer thicknesses can
be varied depending on desired sheet material characteristics. For
example, the polyester layer which is better suited for accepting
printed indicia than the polyethylene, can be made somewhat thicker
to provided increased stiffness to the bag. This can be quite
important where the bag is to function as a pouring bag and will be
lodged or stored in an upright position similar to a jug. The
multilayer plastic material can include additional layers of
material depending on characteristics desired in the finished
material. In another example, the plastic sheet material has outer
layers of polyethylene so that both surfaces of the material are
heat sealable. In yet another example, the plastic sheet material
has a layer of nylon for added strength and/or a barrier layer such
as metal foil, metallized polyester or EVOH. The selection of ply
materials and the number of layers of each material is chosen for
the particular properties desired in the bag. Thus, polyethylene
has good heat sealing properties and relatively high strength. A
copolymer polyethylene with high elastomeric content can be used
where a softer material is required. The sheet film material or
particular web portions used in the bag construction can be formed
from thermoplastic film that has been oriented during manufacture
to impart mechanical strength along a particular axis or at a
critical stress site. Such oriented strength can be imparted by for
example stretching at ambient temperatures, melt orienting during
extrusion, etc. Heat sealing and bonding of layers of sheet
material is effected by the application of temperature and pressure
for a predetermined time at locations where the layers are to be
heat sealed. The temperature, pressure and time are selected based
on the particular nature of the sheet materials being bonded
together. Bonding is typically effected at multiple bonding
stations, with the bonded material subsequently being cooled.
[0067] Whereas the various welded seams, whether or not they
incorporate a strengthening element, are shown as straight lines,
other more complex weld shapes can be adopted for functional and
aesthetic reasons. Thus, a weld may contribute to any or all of
structural shape, strength sealing and "posture" benefits. For
effective sealing, both to prevent loss of contents and also to
prevent intrusion from outside of contaminants, weld elements must
overlap at their junctions. If the weld seams incorporate a
strengthening element, then it may be appropriate to use a
strengthening element which is non-linear.
[0068] There have been described herein various embodiments of a
bag structure. Also described in brief detail are particular
production process steps involved in manufacturing such bag
structures. Such embodiments and processes have features that
distinguish the present invention from the prior art. It will be
apparent to those skilled in the art that the bags and the
manufacture thereof may be modified in numerous ways and may assume
many embodiments other than the preferred forms specifically set
out and described above. Accordingly, it is intended by the
appended claims to cover all modifications of the invention which
fall within the scope of the invention.
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