U.S. patent number 3,687,356 [Application Number 04/467,416] was granted by the patent office on 1972-08-29 for gusseted type bags.
This patent grant is currently assigned to St. Regis Paper Company. Invention is credited to John J. Goodrich, Chester E. Waxlax.
United States Patent |
3,687,356 |
Goodrich , et al. |
August 29, 1972 |
GUSSETED TYPE BAGS
Abstract
A bag of tubular form comprising a plurality of contiguous plies
of flexible sheet material, said bag having a front surface and an
oppositely disposed rear surface adapted to overlap said front
surface at one end of said tube when said bag is in its assembled
condition, said bag being longitudinally and reversely creased
along diametrically opposed portions to provide a pair of
oppositely disposed gussets interposed between said front and rear
surfaces, each of said gussets having a front portion and a stepped
rear portion adapted to overlap said front portion within the
overlap area of said front and rear surfaces at said end of the
tube when said bag is in its assembled condition, and with the bag
plies extending progressively and successively one beyond another
at each surface portion at said bag end, and a bonding agent in a
dormant state being applied on each surface portion at said bag
end, and said bonding agent being reactivatable to close said bag
subsequent to a later bag filling operation.
Inventors: |
Goodrich; John J. (Pensacola,
FL), Waxlax; Chester E. (New City, NY) |
Assignee: |
St. Regis Paper Company (New
York, NY)
|
Family
ID: |
23855603 |
Appl.
No.: |
04/467,416 |
Filed: |
June 28, 1965 |
Current U.S.
Class: |
383/85; 383/116;
383/113 |
Current CPC
Class: |
B65D
31/10 (20130101); B65D 31/02 (20130101) |
Current International
Class: |
B65D
30/20 (20060101); B65D 30/10 (20060101); B65D
30/08 (20060101); B65d 031/02 () |
Field of
Search: |
;229/53,55,68,62,57,58,55 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,366,379 |
|
Jun 1964 |
|
FR |
|
288,177 |
|
Mar 1965 |
|
NL |
|
Primary Examiner: Norton; Donald F.
Claims
What is claimed is:
1. A bag of tubular form comprising a plurality of contiguous plies
of flexible sheet material, said bag having a front surface and an
oppositely disposed rear surface adapted to overlap said front
surface at one end of said tube when said bag is in its assembled
condition, said bag being longitudinally and reversely creased
along diametrically opposed portions to provide a pair of
oppositely disposed gussets interposed between said front and rear
surfaces, each of said gussets having a front portion and a stepped
rear portion adapted to overlap said front surface within the
overlap area of said front and rear surfaces at said end of the
tube when said bag is in its assembled condition, and with the bag
plies extending progressively and successively one beyond another
at each surface portion and each gusset portion at said bag end,
and a bonding agent in a dormant state being applied on each
surface portion and each gusset portion at said bag end, and said
bonding agent being reactivatable to close said bag subsequent to a
later bag filling operation.
2. A bag of tubular form comprising a plurality of contiguous plies
of flexible sheet material, said bag having a front surface and an
oppositely disposed rear surface adapted to overlap said front
surface at one end of said tube when said bag is in its assembled
condition, said bag being longitudinally and reversely creased
along diametrically opposed portions to provide a pair of
oppositely disposed gussets interposed between said front and rear
surfaces, each of said gussets having a front portion and a stepped
rear portion adapted to overlap said front surface within the
overlap area of said front and rear surfaces at said end of the
tube when said bag is in its assembled condition, and with the bag
plies extending progressively and successively one beyond another
at each surface portion and each gusset portion at said bag end,
and a bonding agent in a dormant state being applied on each
surface portion and each gusset portion at said bag end, and said
bonding agent being reactivatable to close said bag subsequent to a
later bag filling operation, the opposite end of said bag being the
reverse of and complementary to that of said one end, the overlap
portion thereof being folded over and adhered to the rear surface
of said bag to close said bag end, the innermost ply having bonded
thereto a coating layer of a heat sealable thermoplastic material,
and the opposed surfaces of said layer being heat sealed together
adjacent said closed bag end.
3. A bag of tubular form comprising a plurality of contiguous plies
of flexible sheet material, said bag having a front surface and an
oppositely disposed rear surface adapted to overlap said front
surface at one end of said tube when said bag is in its assembled
condition, said bag being longitudinally and reversely creased
along diametrically opposed portions to provide a pair of
oppositely disposed gussets interposed between said front and rear
surfaces, each of said gussets having a front portion and a stepped
rear portion adapted to overlap said front surface within the
overlap area of said front and rear surfaces at said end of the
tube when said bag is in its assembled condition, and with the bag
plies extending progressively and successively one beyond another
at each surface portion and each gusset portion at said bag end,
and a bonding agent in a dormant state being applied on each
surface portion and each gusset portion at said bag end, and said
bonding agent being reactivatable to close said bag subsequent to a
later bag filling operation, said bag plies being composed of paper
and said innermost paper ply having bonded thereto a moisture
impervious coating layer.
4. A bag of tubular form comprising a plurality of contiguous plies
of flexible sheet material, said bag having a front surface and an
oppositely disposed rear surface adapted to overlap said front
surface at one end of said tube when said bag is in its assembled
condition, said bag being longitudinally and reversely creased
along diametrically opposed portions to provide a pair of
oppositely disposed gussets interposed between said front and rear
surfaces, each of said gussets having a front portion and a stepped
rear portion adapted to overlap said front surface within the
overlap area of said front and rear surfaces at said end of the
tube when said bag is in its assembled condition, and with the bag
plies extending progressively and successively one beyond another
at each surface portion and each gusset portion at said bag end,
and a bonding agent in a dormant state being applied on each
surface portion and each gusset portion at said bag end, and said
bonding agent being reactivatable to close said bag subsequent to a
later bag filling operation, the innermost ply of said bag being
composed of a heat sealable thermoplastic material and the
remaining plies being made of paper, opposed portions of said
plastic ply being heat sealed together transversely of said bag at
a closed end thereof.
Description
The invention pertains to improvements in gusseted bags of the
so-called pinch bottom type. Gusseted bags constructed in
accordance with the invention may be fabricated from flexible sheet
material, such as paper or the like and find wide use in protecting
many different types of commodities during transit.
The invention pertains more particularly to a bag of tubular form
comprising a plurality of contiguous plies of flexible sheet
material wherein the bag has a front surface and an oppositely
disposed rear surface which is adapted to overlap the front surface
at one end of the tube when the bag is in its assembled condition.
The bag is longitudinally and reversely creased along diametrically
opposed portions in order to provide a pair of oppositely disposed
gussets which are interposed between the front and rear surfaces.
Each of the gussets has a front portion and a stepped rear portion
which is adapted to overlap the front portion within the overlap
area of the front and rear surfaces at the end of the tube when the
bag is in its assembled condition.
The invention has as one of its aims, the provision of a new and
improved gusseted type bag which has greatly superior closure
strength and bonding characteristics as compared to practices of
the prior art; and which controls contamination and insect
infestation.
The invention provides as another of its aims, a bag closure which
is of simple and inexpensive construction and which when completed
positively seals the bag mouth against leakage and sifting even
though the bags are roughly handled in transit. Such gusseted bag
construction is accomplished with a minimum of bag material
wastage.
Another feature of the invention resides in the provision of a new
and improved gusseted type bag having a heat sealable inner ply of
an impervious character which may be heat sealed without having to
penetrate all of the plies of the bag with heat, and which is also
of superior strength characteristics by means of overlapping the
inside ply and thereby obtaining a better bond with additional
strength. Such a structure is useful for retaining liquids or gases
within or without the bag.
The invention provides as another of its aims, a gusseted type bag
of the character aforesaid having a greatly simplified bag which
may be simply closed and sealed in the packer's factory without the
necessity of applying additional adhesive material and without
excessive adhesive flowing over the wrong portions of the package,
and which simplifies the handling and filling of the bag by the
packer as well as simplifying the opening procedure for the
ultimate consumer.
As still another feature of the present invention, a new and
improved gusseted type bag is provided which has a more pleasing
appearance and fewer wrinkles and which can still maintain a
satisfactory marketable package even when there is slight deviation
in the fold line as well as deviations in the bonding agent
application.
According to one form of the invention the innermost ply of the
gusseted type bag is fabricated from a heat sealable material. The
rear surface of the innermost ply is cut substantially flush with
the stepped rear portion of the other plies and the front surface
of the innermost ply is cut substantially flush with the front
portion of the other plies at the end of the tube when the bag is
in its assembled condition.
The invention may be embodied in bags of single wall or multi-wall
construction. As applied to multi-wall bags, further improvements
of the invention are obtained by successively stepping the
successive plies at the bag ends, and/or by similarly successively
stepping the plies in only the gusseted portions of the bag. In
this way, upon forming the bag closure by folding over the bag end
and adherently bonding against one of the bag surfaces, all of the
bag plies participate and contribute to the bonding action.
In accordance with a further aspect of the invention, a bonding
agent in a dormant state is applied to the surfaces of the gusset
portions as well as the front and rear surfaces at the end of the
tube when the bag is in its assembled condition. The bonding agent
is such that it may be reactivated to close the bag subsequent to a
later bag filling operation. Further, in a modified form of the
invention the bonding agent may be applied in transverse spaced
strips on the face of the steps at the end of the tube. In still
another form of the invention, the bonding agent is applied
adjacent the upper edges of the steps so that portions of the
gusset may be adhered to the rear surface of the tube. This is
particularly advantageous since it eliminates the necessity for
manually tucking in the gussets or corners of the bag, which would
otherwise be required after the filling operation.
As another aspect of the invention the longitudinal width of the
rear gusset exposed surfaces may be substantially less than the
width of the rear wall exposed surface or the front gusset exposed
surfaces.
Still another aspect of the present invention resides in the
provision of a new and improved gusseted type bag having a free
floating polyethylene inside ply. This provides a moisture and air
impervious inner ply which may expand or contract without
encountering adverse tension or compression forces normally
accompanying inter-bonded plies.
Also, according to the present invention a thumb notch may be
provided in the outside ply of the front surface adjacent the top
edge of the rear surface when the rear surface is folded over and
adhered to the front surface.
There has thus been outlined rather broadly the more important
features of the invention in order that the detailed description
thereof that follows may be better understood, and in order that
the present contribution to the art may be better appreciated.
There are, of course, additional features of the invention that
will be described hereinafter and which will form the subject of
the claims appended hereto. Those skilled in the art will
appreciate that the conception upon which this disclosure is based
may readily be utilized as a basis for the designing of other
structures for carrying out the several purposes of the invention.
It is important, therefore, that the claims be regarded as
including such equivalent constructions as do not depart from the
spirit and scope of the invention. Several embodiments of the
invention have been chosen for purposes of illustration and
description, and are shown in the accompanying drawings, forming a
part of the specification, wherein:
FIG. 1 is a perspective view of a gusseted type pinch bottom bag
constructed in accordance with the invention;
FIG. 2 is an enlarged perspective view showing details of the
closure structure according to one form of the invention;
FIG. 3 is a plan view of a blank of flexible sheet material for
fabrication into a multi-ply or multi-wall bag;
FIG. 4 is a fragmentary perspective view showing the closure
portion of a gusseted type bag according to a modified form of the
invention;
FIG. 5 is a longitudinal sectional view taken substantially along
the lines indicated at 5--5 in FIG. 4;
FIG. 5a is a fragmentary view showing overlapping closure means of
the inner most ply;
FIG. 6 is a fragmentary perspective view showing the closure
portion of a gusseted type bag according to the invention after the
exposed surfaces have been folded over in bonded condition;
FIG. 7 is a longitudinal sectional view taken along the line
indicated at 7--7 in FIG. 6 and showing details of the bonding
between the exposed surfaces and the face of the front wall of the
bag;
FIG. 8 is a fragmentary perspective view showing a modified form of
gusset structure when the bag tube is in its flattened
condition;
FIG. 9 is a fragmentary perspective view similar to FIG. 8, but
showing the gusset structure after the package has been partially
opened;
FIG. 10 is a fragmentary elevation showing another modified form of
gusset construction according to the invention;
FIG. 11 is a fragmentary elevation illustrating still another form
of closure means according to the invention, wherein portions of
the gussets are adhered to the rear surface;
FIG. 12 is a perspective view of a gusseted type bag showing the
thumb notch opening means;
FIG. 13 is a perspective view similar to FIG. 12, but illustrating
the operation of the thumb notch opening means; and
FIG. 14 is a perspective view of a modified form of the invention
showing a multi-wall bag construction wherein the bag plies are
successively stepped at the bag ends.
In the embodiment of the invention illustrated in FIGS. 1-3, the
gusseted type bag is formed from a single ply 10, FIG. 1, or a
plurality of contiguous plies including plies 10, 12 and 14, FIG.
3, of flexible sheet material, such as kraft or other paper. The
innermost ply may have a thin plastic coating of polyethylene or
the like, applied to one or both surfaces thereof for moisture
proofing. Preferably when a plurality of plies are used, the plies
10, 12 and 14 are longitudinally stepped as indicated in FIG. 3 so
that when the blank is formed into a tubular member the joining of
the respective longitudinal edges of each ply will be staggered. It
is noted that only one end of the bag or tubular structure is
shown, however, it is understood that the other end of the bag is
constructed in a like complimentary stepped manner.
As best seen in FIGS. 1 and 2, the bag has a front wall surface 16
and an oppositely disposed rear wall surface 18 adapted to overlap
or extend above the front surface at one end of the tube when the
bag is in its assembled condition. Referring to FIG. 1, the bag is
longitudinally creased along fold lines 20, 22, 24 and 26, and
further, the bag is longitudinally and reversely creased along
diametrically opposed lines 28 and 30, thereby forming a pair of
oppositely disposed gussets indicated generally at 32 and 34 which
are interposed between the front and rear walls or surfaces 16 and
18.
Each of the gussets 32 and 34 have a front portion 36 and a stepped
rear portion 38, as seen in FIG. 1. The rear portion 38 is adapted
to overlap the front portion 36 within the overlapped area of the
front and rear wall surfaces 16 and 18, thereby forming a rear wall
exposed surface 40, rear gusset exposed surfaces 42, front gusset
exposed surfaces 44, and a front wall exposed surface 46.
Still referring to FIGS. 1 and 2, there is shown a plurality of
spaced transversely extending strips of a bonding agent in a
dormant state. The bonding agent is a pre-applied type of
thermoplastic resin adhesive of any suitable type. While such
adhesive could be applied to substantially cover all of the exposed
surfaces at the end of the bag, it is preferable that it be applied
in horizontally, transversely disposed, spaced strips. As seen in
FIGS. 1 and 2, a first strip 48 is applied on the rear wall exposed
surface 40 and extends substantially across the width of the bag. A
second strip 50 extends across the rear gusset exposed surfaces 42
and preferably across the adjacent portion of the rear wall exposed
surface as at 51. Next, a third strip 52 extends across the front
gusset exposed surfaces 44 and preferably across the adjacent
portion 53 of the rear wall exposed surface as at 53, and a fourth
strip of bonding agent 54 is applied to the front wall exposed
surface 46. When packaging certain materials, the strip of bonding
agent 54 may be dispensed with, but when packaging other
commodities the bonding agent strip 54 serves a very important
function. That is, the latter strip serves to make the bag
contamination or insect proof, otherwise there is the possibility
that insects may penetrate through the corners of the bag thereby
gaining access to the interior thereof. Moreover, the strip of
bonding agent 54 serves as an added measure of protection in the
event that the application apparatus of the strips of bonding agent
48, 50 and 52 misfires or skips a spot, the package would
nevertheless be satisfactorily sealed.
As best seen in FIGS. 6 and 7, closure of the package is
accomplished by folding the end along the fold crease 56, thus to
adhere the bag end to the outer ply of the front surface 16. As
seen in FIG. 7, each of the adhesive strips 48, 50, 52 and 54 are
in direct contact with the front surface. This is why applicants'
bag is of substantially superior strength as compared to bags of
the prior art.
Normally the bags are shipped to the packers in the condition as
shown in FIG. 2 with the bonding medium already applied. The packer
opens the top of the bag and inserts a filling spout therein for
filling the bag with a desired commodity. Thereafter, the operators
tuck-in the gusset portions and fold over the end of the bag along
crease line 56, FIG. 2. Normally heat and pressure are applied to
reactivate the preapplied bonding agent to thereby permanently
close the bag. This may be accomplished by means of hot pressure
bars or hot rollers, as desired. Also, with certain types of
bonding agents, a hot air blast may be employed to reactivate the
bonding agent, or in still other instances the bonding agent may
require chemical reactivation. It will be appreciated that with the
aforementioned type of preapplied bonding agent, the packer is not
troubled with the problem of applying adhesive to the bag in his
plant. This may be particularly desirable when packaging
comestibles wherein adhesive may accidentally become intermingled
with the contents of the package.
Referring to FIGS. 4 and 5, the innermost ply designated generally
at 58 has a front wall exposed surface 60 which extends beyond the
other front wall plies and a rear wall exposed surface 62 which
extends below the other rear wall plies. Preferably the front
surface 60 is substantially flush with the front gusset exposed
surfaces 64, and the rear wall exposed surface 62 is flush with the
rear gusset surfaces 66. The innermost ply 58 is fabricated from
heat seal material, and accordingly, the exposed surfaces thereof
may be subjected to heat and thereby sealed without the necessity
of the heat passing through as many plies as would be necessary if
the inner ply was of the same relative height as the outer plies.
Further, the inner ply 58 may be fabricated from many different
types of materials porous and non-porous. For example, such
materials include polyolefines such as polyethylene and
polypropylene, polyamides such as nylon and polyesters such as
polyalkylene derivatives of polycarboxylic acids especially
polyethylene terephthlite. Further, the inner ply may be fabricated
into a tubular member in a suitable manner such as that disclosed
in U.S. Pat. No. 3,399,096, issued on Aug. 27, 1968.
If the inner ply 58 is thermoplastic coated then, as best seen in
FIG. 5a, the rear wall 62 of the inner ply 58 may be doubled over
upon itself and the front wall surface 60 overlapped thereover in
order to form a hermetic seal between the two thermoplastic
surfaces.
Referring to FIGS. 8 and 9, there is illustrated a modified form of
gusset construction. In this form a front gusset surface 68 and a
rear gusset surface 70 are cut to substantially the same height or
flush, and both are disposed with the overlapped area of the rear
wall exposed surface 40 and the front wall exposed surface 46.
Further, according to this form of the invention, the top edge of
the front and rear gusset exposed surfaces 68 and 70 are serrated
or are provided with diamond or round notching as indicated at 72.
The first transverse strip of bonding agent 74 is applied across
the rear wall exposed surface 40, and a second transverse strip of
bonding agent is applied across the top edge of the gussets
including the serrated edge portion 72, thereby adhering both the
front and back gussets 68 and 70 to the rear wall 40 at the top of
the bag. This has the advantage of preventing leakage of packaging
material at the outer extremities of the gussets, and also
facilitates closure of the bag after filling with packaging
material since it eliminates the necessity for manually tucking in
the corners of the gussets which would otherwise be required.
Referring to FIG. 10, there is illustrated a modified form of
gusset arrangement wherein three strips of preapplied bonding agent
in a dormant state are applied to the rear wall exposed surface, to
the rear gusset exposed surfaces and to the front gusset exposed
surfaces respectively. That is, one strip of bonding agent 78 is
applied transversely of the bag across the rear wall exposed
surface 76; a second strip 80 of bonding agent is applied to the
upper edge of the rear gusset exposed surface 82 so that a portion
of the bonding agent appears on the top edge of the rear gusset
exposed surface 82 and a portion of the bonding agent appears on
the adjacent portion of the rear wall exposed surface 76, thereby
bonding the two surfaces together along the line 84 as well as
along the line 86; and a third strip 88 of bonding agent is applied
along the top edge of the front gusset exposed surface 90 in an
overlapping manner as seen in FIG. 10 so that the front gusset
exposed surface 90 is bonded to the rear gusset exposed surface 82
along the line 92 and the front gusset surface 90 is also bonded to
the rear wall exposed surface 76 along the line 94. As pointed out
above, bonding of the gussets one to the other and to the rear wall
serves to prevent leakage of the packaging material at the
extremities of gussets and facilitates closure of the bag after
filling with packaging material.
Referring next to FIG. 11, there is illustrated a further
modification of the invention. According to this embodiment, the
front gusset exposed surface is stepped below the rear gusset
exposed surface and the upper edges of both gusset surfaces are
provided with a serrated or sawtooth type contoured edge as
indicated at 96 and 98, respectively. This construction provides a
longer effective linear edge for providing better bonding
characteristics between the front gusset 90 and the rear gusset 82
as well as the rear gusset 82 and the rear wall exposed surface
76.
Referring to FIGS. 12 and 13, there is shown new and improved means
for opening a gusseted type bag. A thumb notch 100 is formed in the
outermost ply of a multi-ply bag by an interrupted line of slit 102
therein disposed adjacent the top edge of the rear wall 18 when the
rear wall is folded over in sealed condition. Since the
aforementioned strips of adhesive material are adhered to the
outermost ply of the front wall 16, the thumb notch 100 tends to
rip the outermost ply of the front wall 16 underneath the folded
over portion of the back wall 18, and thereby provides a thumb grip
to grasp the so-folded over back wall that it can be easily lifted
to open the bag as shown in FIG. 13.
Referring to the multi-wall bag constructions, the bag plies may be
successively stepped at the bag ends to provide additional
adherence on forming the bag closure. Thus, referring to FIG. 14,
the rear wall exposed surface comprises a plurality of plies which
may, for example, include three plies including an outside ply 104,
a second ply 106 and an inside ply 108. The rear gusset exposed
surfaces include an outside or first ply 110, a second ply 112 and
an inside or third ply 114. The front gusset exposed surfaces
include plies 116, 118 and 120. The front wall exposed surface
includes a first ply 122, a second ply 124 and a third ply or
inside ply 126. It will be appreciated that each of the plies in
each of the exposed surfaces has a bonding agent in a dormant state
applied thereto as at 128, FIG. 14. The bonding agent is
reactivatable to permanently close the bag subsequent to a later
bag filling operation. In this way, portions of all the bag plies
in all surfaces including the gusset areas, upon forming the bag
closure by folding over along the fold line 130 and reactivating
the bonding agent, are adherently bonded to the bag surface.
It will be understood that various changes in the details,
materials and arrangements of parts which have been herein
described and illustrated in order to explain the nature of the
invention, may be made by those skilled in the art within the
principle and scope of the invention, as expressed in the appended
claims.
* * * * *