U.S. patent number 3,827,472 [Application Number 05/226,680] was granted by the patent office on 1974-08-06 for reclosable bag.
This patent grant is currently assigned to Kabushiki Kaisha Seisan Nipponsha. Invention is credited to Tatsuro Uramoto.
United States Patent |
3,827,472 |
Uramoto |
August 6, 1974 |
RECLOSABLE BAG
Abstract
A flexible bag structure having an outer layer and an inner
layer with the layers bonded to each other and being coextensive to
the top of the bag, and the inner layer formed of a plastic with
interlocking rib and groove profiles integral with the plastic to
close the top of the bag and tear strip means integral with the
inner layer and opposite the coextensive outer layer for tearing
the top off of the bag with the tear strip means preferably in the
form of a pair of ribs.
Inventors: |
Uramoto; Tatsuro (Tokyo,
JA) |
Assignee: |
Kabushiki Kaisha Seisan
Nipponsha (Tokyo, JA)
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Family
ID: |
26920771 |
Appl.
No.: |
05/226,680 |
Filed: |
February 16, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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882491 |
Dec 5, 1969 |
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Current U.S.
Class: |
383/204; 383/107;
383/119; 383/63; 383/116 |
Current CPC
Class: |
B65D
33/2541 (20130101); B65D 33/2533 (20130101); A44B
19/16 (20130101) |
Current International
Class: |
A44B
19/10 (20060101); A44B 19/16 (20060101); B65D
33/25 (20060101); B65d 031/02 () |
Field of
Search: |
;150/3 ;229/66
;24/21C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Norton; Donald F.
Attorney, Agent or Firm: Hill, Gross, Simpson, Van Santen,
Steadman, Chiara & Simpson
Parent Case Text
RELATED APPLICATIONS
The present application is a continuation-in-part of my copending
application, Ser. No. 882,491, filed Dec. 5, 1969, entitled
"Air-Tightly Sealable Pouch Formed of Laminate Members Integrally
Combining Engaging or Coupling Fastener Elements", now abandoned.
Claims
I claim as my invention:
1. A bag structure comprising in combination,
a bag body having walls with an upper end,
said walls having an outer layer and having an inner layer formed
of plastic coextensive with the outer layer to the upper end and
bonded thereto,
said outer layer formed of a first material having predetermined
characteristics for the outer layer of the bag,
said inner layer formed of a second material having predetermined
characteristics for the inner layer of the bag,
rib and groove cooperatively shaped releasable interlocking
profiles near the upper end of the bag integral with the plastic of
the inner layer,
and tear guide means formed in the plastic of the inner layer above
said profiles for guiding the tearing of both layers with the outer
layer extending uniformly over the area of the inner layer carrying
said tear guide means.
2. A bag structure constructed in accordance with claim 1 wherein
said tear guide means includes a raised rib projecting inwardly and
extending parallel to the profiles.
3. A bag structure constructed in accordance with claim 1 wherein
said tear guide means includes a pair of parallel ribs defining a
tear line between them.
4. A bag structure comprising in combination,
bag walls with a top end and with an inner layer formed of a
plastic with releasably interlocking rib and groove elements on
facing inner surfaces integral with said inner layer extending
parallel to the top of the bag walls for closing the bag,
tear guide means extending across the top of the bag above the rib
and groove elements defining a tear line and formed in said inner
layer,
and an outer layer of a material having different physical
characteristics than the inner layer to protect the inner layer and
laminated thereto and extending to the top of the inner layer with
the walls of the bag joined at the top end to form a closed top
end.
5. A bag structure constructed in accordance with claim 4 wherein
the bottom of the bag is open, and the rib and grooves are
interlocked.
6. A bag structure constructed in accordance with claim 4 wherein
said tear guide means includes a rib projecting inwardly from the
inner layer.
7. A bag structure constructed in accordance with claim 4 wherein
said rib element is of a material harder than the inner layer of
film.
8. A bag structure constructed in accordance with claim 4 wherein
said tear guide means includes a pair of parallel ribs with
weakened material between the ribs in the inner layer.
9. A bag structure constructed in accordance with claim 4 wherein
said tear guide means and said rib and groove elements are formed
by extrusion with the inner layer.
10. A bag structure constructed in accordance with claim 4 wherein
said inner and outer layers are fusion bonded.
11. A bag structure constructed in accordance with claim 4 wherein
said layers are joined by an adhesive material extending
therebetween.
Description
BACKGROUND OF THE INVENTION
The invention relates to improvements in air-tight bags having
reopenable closure structures at the top which interlock to exclude
air and moisture from the contents thereof and which open when
pulled apart to afford access to the interior thereof.
More particularly, the invention relates to an improved arrangement
for bags of the reopenable type which are initially sealed, and are
torn open by the user before using. After being torn open,
interlocking rib and groove profiles beneath the torn part serve to
reclose the bag when it is not in use and provide a reopenable
closure for access to the contents of the bag. Such a bag has to
comply with various functional requirements to be successful. For
example if used for foodstuffs, it should be impervious to air and
moisture to protect the foodstuffs from surrounding contamination,
and should be impervious to greases, sugars or liquids or whatever
the foodstuffs contain to prevent leakage. These requirements place
heavy demands on any one material, and it is desirable to provide a
multi-layered bag, and it is accordingly, an object of the present
invention to provide an improved multi-layered bag of unique design
which provides an improved tear strip arrangement at the top for
initially opening the bag.
Before proceeding with a discussion of the specific features of
this bag, a brief review of the importance of impervious reopenable
bags will be useful. In the provision of plastic film bags, they
are frequently used for contents which are subject to deterioration
when permitted to come in contact with atmospheric air. The closure
is, therefore, designed to exclude air and obtain preservation of
the contents for a relatively long time. This type of bag and
closure is conventionally made of suitable plastic such as
polyethylene which can be obtained by extrusion processes. This
type of bag is suitable for containing many types of products which
require, for their preservation, the prevention of the penetration
of air and moisture to the interior since the contents undergo
chemical or physical changes due to the oxygen from the air and the
moisture from the atmosphere, and if these are permitted to
penetrate the bag, the contents are progressively deteriorated as
time passes. Conventional types of containers employ vacuum
packages or cans which evacuate atmospheric air from the contents
before they are closed. This type of container, however, must be
consumed after the container is open, or if a required amount is
taken out of the container, the necessity arises for providing a
container for the preservation of the remainder. Plastic film bags
with air-excluding fasteners have an effective function for taking
care of such contents to protect them.
However, in conventional flexible plastic bags, provisions are not
made to absolutely prevent the penetration of air and to insure the
prevention of inadvertent opening or leakage and the resultant
admission of air and deterioration of the contents.
In a sealing fastener means with a flexible pouch which is used to
prevent the penetration of air into the interior of the bag, the
following requisites must be met:
a. The physical function of the engaging fastener means must be
sound enough to stand any pressure force exerted either from the
outside or from the inside of the pouch and such engaging force
must be strong enough to maintain its function until the bag is
broken.
b. The disengagement or opening of the fastener means must be
easily effected when the contents are partly or entirely taken
out.
c. The sealing fastener means must have the ability to inhibit any
penetration of air from the atmosphere outside of the pouch or the
escape of air from inside the pouch.
d. The pouch body must have the ability to inhibit the passage of
air from either the outside in or from the inside out so that
through the cumulative effect of both the fastener and the pouch,
the package as a whole is capable to prevent deterioration of the
contents. Also, the conventional fastener means for closing pouches
are formed from a simple combination of joining fastener means to
the pouch body, both being of plastic such as polyethylene. In the
relationship between the fastener and the pouch body, such
conventional devices are satisfactory with respect to the above
requisites (a) and (b) from maintenance of the contained products,
but such devices lack the important structural arrangements to
satisfy (c) and (d) for interception of the atmospheric air
required to be excluded for safe perservation of the contents.
It is accordingly an object of the present invention to provide an
improved flexible closure structure which will provide a more
secure closure for a bag in the sense that it will exclude the
passage of air in the atmosphere into the contents of the bag and
prevent the flow of air from the interior out through the fastener
for the bag.
A further object of the invention is to provide an improved plastic
sheet suitable for making bags with the sheet having parts
inter-related to be readily formed into a bag.
Another object of the invention is to provide a new and improved
closed bag structure which can be torn open and which has
releasably interlocking rib and groove elements within the
opening.
Other objects and advantages will become more apparent with the
disclosure of the preferred embodiment of the invention in
connection with the claims, specification and drawings in
which:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a bag constructed in accordance with the
principles of the present invention;
FIG. 2 is an enlarged fragmentary sectional view showing the parts
separated for purposes of clarity;
FIG. 2a is an enlarged fragmentary sectional view taken
substantially along line II-II of FIG. 1;
FIG. 2b is an enlarged fragmentary view showing the manner in which
a bag constructed in accordance with the invention is opened;
FIG. 3 is a greatly enlarged sectional view showing a portion of
the fastener of the invention;
FIG. 4 is a greatly enlarged sectional view showing the elements of
FIG. 3 as they first interengage; and
FIG. 5 is a greatly enlarged sectional view similar to FIGS. 3 and
4 but showing the relative positions of the parts when fully
interengaged.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1, 2, 2a and 2b, a bag or pouch construction 1 is
formed with seams 6 along the side edges. The bottom of the bag is
open for filling. The bag will normally be inverted when filled,
and a heat seam will be formed along the bottom edge 11 for closing
the bag.
The material of the bag is originally formed by an extrusion
process which forms a flat sheet. The sheet may initially be
extruded as flat or in a tube and slit to form a flat sheet.
Actually, a multiple sheet is formed with the sheets bonded
together, and these separate sheets may be extruded separately or
extruded at the same time and brought together adjacent the
extrustion head to be laminated to each other. The upper sheet will
form the plain outer layer of the bag, and the lower sheet will
form the inner layer which carries the rib and groove profiles and
the tear guide elements. The sheet is extruded as a continuous
length, and cut into short lengths which are doubled at their
center to form the fold shown at 10 in FIG. 2a. The sides of the
folded sheet are then sealed to each other to form the side seams
of the bag with the bottom remaining open until the bag is
filled.
When the sheet is folded to form the bag, as shown in the form of
FIGS. 1 and 2a, the inner layer 4 will be a thin plastic film
having a characteristic suitable for the inner surface of the bag
and suitable for the interlocking rib and groove elements 2a and
2b. A very thin layer of plastic 4 may be employed which provides
an air and moisture impervious layer and which, when combined with
the outer layer 3, has sufficient stiffness to function as a bag
wall. Thus, each layer can be chosen to supply its own optimum
characteristic, e.g., the inner layer can be chosen to provide a
seal, the outer layer can be chosen to provide stiffness.
The bag walls are made up of the first outer layer and the second
inner layers of plastic film which are laminated to each other,
such as by being joined at the time of extrusion, or by being
placed together and subjected to external heat or by being joined
by an adhesive material extending between the layers. In some
instances the outer layers can also be formed of plastic film of a
greater thickness or of a film which has an inherent characteristic
of greater stiffness. By providing the two layers of film thus
laminated, it becomes easier to form and extrude each of the
layers. The extrusion process for the inner layer can be carefully
controlled for better formation of the rib and groove elements, and
the inner layer can be quite thin since it does not have to provide
a support for these elements. The outer layer can be extruded more
rapidly and with a coarser extrusion apparatus since it is not
necessary to obtain the careful tolerances of formation that are
necessary with the rib and groove element. Also, if there happen to
be any pinholes in either of the two layers, they will be sealed by
the laminated opposing layer of film.
As shown in FIG. 1, the bag is formed with an open bottom 11 and
side seams 6. Integral with the inner layer 4 is the rib element 2a
and groove element 2b. These elements may take different forms and
shapes, but a preferred simple arrangement is shown in the drawings
of FIGS. 2, 2a and 2b, and details of modified versions are shown
in FIGS. 3 through 5.
The rib and groove elements 2a and 2b are cooperatively shaped so
that they will interlock when pressed together and will separate
when pulled apart by grasping the upper two edges of the bag.
The bag is initially formed as shown in FIG. 2a, and the rib and
groove elements 2a and 2b are pressed together. The bag is then
filled from the bottom, and a heat seal is formed so that a
completely sealed bag results.
At the time of use, the top is torn open to afford access to the
contents and to first permit separating the rib and groove
elements. This tearing operation is shown in FIG. 2b wherein the
user grasps the top edge and pulls it away from the bag so that a
tear occurs between the upper and lower ribs 5 and 5' and between
the upper and lower ribs 9 and 9'. That is, along lines 5a and 9a
as shown in FIG. 2. This tear line will follow straight across the
top of the bag and will not deviate downwardly to tear down into
the rib and groove elements, nor will it turn upwardly to run off
the top of the bag. It will leave a relatively smooth top so that
flanges will remain for pulling apart to separate the rib and
groove elements. The ribs 9 and 5, and the ribs 9' and 5', may be
either in alignment with each other as shown in FIG. 2a or may be
slightly offset in location as shown in FIG. 2b.
While the means for guiding the tear across the top of the bag is
shown in a preferred form as embodying pairs of ribs, it will be
understood that other forms may be used such as a single rib, or a
perforated line of weakened tear resistance such as by spaced
notches or a V-groove. In any event, the entire tear guide means is
carried by the inner layer 4 and contributed to the bag when the
inner layer is laminated to the outer layer. This is a new concept
which provides for an optimum tear function and yet does not
interfere with the construction of the outer layer of the bag.
Also, the tear guide ribs or other means are completely hidden
within the bag and do not provide objectionable projections or
grooves on the outer surface of the bag.
In some circumstances, the outer layer 3 may be transparent and the
tear guide means may be colored so that the user may immediately
locate and identify the tear guide means. It is also contemplated
that tear starting means may be provided on either side of the bag
such as a notch, which will indicate to the user where the tear is
to begin and will insure that the tear occurs at the proper
location.
Also, when the top of the bag is removed as indicated by the tear
strip 12, the remaining portion provides convenient flanges, as
provided by the ribs 9 and 5 for gripping the top of the bag and
pulling apart the rib and groove elements.
The doubled over top 10 provides a complete seal for the bag until
it is used. Also, the tear guide arrangement and the doubled over
top provide a relatively stiff top for the bag which helps hold its
form during storage and helps the top to be torn off.
It is also contemplated that the material of the tear guide ribs,
whether a single rib or double rib is used, will be of harder
plastic than the other material of the bag. This can be
accomplished by supplying a harder plastic during the extrusion.
With this structure, a relatively thin inner layer can provide all
of the guide support that is needed for a heavy outer layer.
The details of construction of the rib and groove elements are
shown in FIGS. 3 through 5. The rib 2a has a stem A which supports
it on the layer of film 4 and a head with rounded outer surfaces
and which tapers to a smaller size at its distal end.
The groove element 2b has a pair of jaws 8 with hooks E and E' at
their outer ends with inwardly facing planar surfaces that are
slanted to be parallel to the inner surfaces B and B' of the head
so as to lie in surface to surface contact when the elements are
fully engaged as shown in FIG. 5.
The head 2a has a width D which is measured parallel to the film
layer 4, and a depth or height J which is measured normal
thereto.
Similarly, the groove element 8 has a width F and a depth or height
K. These dimensions are such that the width of the head D is at
least as great as the width F between the jaws of the groove
element. The outer curved surface of the head 2a and the inner
curved surfaces of the jaws 8 are such that they are complementary
when the head is first fully inserted between the jaws to the
position shown in FIG. 4. The depth J of the head is less than the
depth K of the recess of the groove element so that the head 2a can
be fully inserted into the recess and past the hooks E and E' and
then seat in the position shown in FIG. 5. The width of the stem A
is such that inner tips of the hooks I AND I' extend substantially
to the sides of the stem A. In fully interengaged position as shown
in FIG. 5, the difference between the depth of the head 2 a and the
groove element is shown at H.
As shown in FIG. 3, the fitting engagement between the head and the
jaws are such that the engaging end portions L and L' of the head
pass the engaging end portions I and I' of the jaws during
insertion. Their positional relationship after engagement is such
that the engaging end portions L and L' of the head are positioned
at a point lower than the end positions I and I' of the jaws.
Because of the presence of space H after their engagement of the
rib and groove elements, as shown in FIG. 5, the rib element can
move loosely in the groove element whenever given impact or rocking
force due to forces from either outside or inside of the bag. The
head thus moves freely in the surface between the head and groove
element and acts as a bearing permitting free rocking movement
preventing the breaking of the seal formed between the rib and
groove. This structural relationship is significant because it
prevents the inadvertent passage of air which might occur in
conventional structures even though the interengagement was not
completely broken.
The pouches are formed by first forming the plastic film such as by
extrusion, and preferably extruding the interengaging elements
therewith in sheet form or tubular form. By cross-sealing
individual bags are then completed.
As an example of use for the bag, a discussion will be provided
where a product is contained which absolutely requires the
exclusion of air for its preservation when packed in a conventional
fastener. When only a desired amount of such a product is taken out
of the pouch, the remainder is retained therein, the fastener means
is closed. A slight amount of oxygen is inevitably intorduced into
the bag when the needed amount of contents are taken out. In the
case of oil containing foodstuffs (such as pies, crackers, potato
chips or biscuits) the introduced oxygen is consumed by the
oxidation of the oil, with the result that oxygen pressure in the
pouch is reduced to substantially zero. Such oxygen has a partial
pressure of about one-fifth a.t. in the atmosphere and there is
produced a difference of partial pressure of oxygen between the
inside and outside of the bag. Consequently, brisk oxygen
penetration into the bag is expedited causing additional oxidation
of the product therein which obviously results in the deterioration
of the flavor and quality of the product and degeneration thereof.
Oxygen in the atmosphere tends not only to deteriorate the quality
of the product but also expedites growth of aerobic germs, causing
early decomposition or degeneration of the product. In case the
contained product is a foodstuff such as a pie, and the quality is
greatly affected by humidity, which contains in itself a small
amount of moisture necessary to maintain its shape and quality, if
the ambient atmosphere is under equal humidity conditions, this
permits maintenance of an optimum humidity of the pie and there
will be no change of quality of the pie since no moisture
absorption nor dehumidification takes place. However, if either
moisture due to dehumidification exceeds the limit of the humidity
condition necessary for maintaining the pie quality, the optimum
humidity of the pie itself and the ambient humidity are unbalanced
causing deterioration and rapid detraction of its value as a
commercial product.
Obviously change of product quality is directly related not only to
humidity but also to temperature to which the product is exposed.
It is known, for example, that the optimum relationship between the
temperature and humidity for preserving the commodities resides
within the range shown in the following table:
Temperature Humidity ______________________________________ Wheat
flour 21.degree.-27.degree.C 60% Chemicals 16.degree.-27.degree.C
35-50% Confectionary 16.degree.-20.degree.C 50-65% Apple
-0.6.degree.-1.0.degree. 78-85% Orange 0.degree.C 80% Sugar
27.degree.C 35% ______________________________________
The above-mentioned units are only a portion of the commodities,
but it may be observed that except for some specific articles which
require low temperatures for their preservation, most of the
commodities require an ordinary temperature of around 20.degree.C,
but are bound more strictly by the humidity in which they are
placed. Thus, the protection against humidity is frequently more
significant than temperature maintenance.
in a humid district, therefore, there is need of providing suitable
means for preventing excess humidity absorption, and to this end,
usually a complementary measure such as the enclosure of a
dessicant is taken. However, such measure increases cost because of
labor, expenses of dessicant and inconvenience of handling due to
increase of the volume.
The foregoing are examples where a fastener means which has no
airtightness allows penetration of air and humidity into and out of
the pouch and causes deterioration of the combined product. In case
the contained article is one having a high fragrance or aroma such
as coffee or bread and the like which requires an optimum humidity
with a certain range for its preservation, it is required to
prevent the release of fragrance or humidity from the container.
Thus, the opening and closing function of an opening fastener for a
flexible bag will attain its desired function only when it serves
both the retention of the packed article, but also to maintain its
quality, particularly when the article is a specific one which
requires protection against humidity and oxidation.
In the improved bag of the instant invention, the bag walls are
formed of a composite layer of material such as cellophane or
polyethylene and aluminum foil or paper sheet. The inside layer is
of plastic film so as to be joinable with the fastener assembly,
and the outside layer of cellophane, foil or paper so as to give
additional protection, body, resistance against scuffing and other
properties which are afforded by the material of the outside
layer.
Referring again to FIGS. 3 through 5, the structure is formed such
that the profile or contour of any selected point of the outer
surface of the head 7 corresponds or is the same as the profile of
the inner surfaces of the jaws 8 except at the end points M and M'
when the head is fully inserted in the groove element. With the
head fully inserted as shown in FIG. 4, the jaws 8 are slightly
pushed apart so that their natural resiliency to return to their
normal position provides a restoring force that tends to urge the
head 7 of the rib outwardly to its normal locked position as shown
in FIG. 5. To enhance the resiliency of the jaws, their thickness
is gradually increased from the outer distal end toward the bottom
where they are attached to the wall. This provides a larger
resilient force for them to grip the head. The relationship between
the jaws 8 and their outer hook ends I, I' is such that they
substantially engage the stem A in the closed position of FIG. 5
thereby further inhibiting the possibility of flow of air past the
closure.
The surfaces B and B' of the head 7 are arranged so that a line
drawn to intersect their tips intersects the plane of the bag wall
within the bag. The surfaes E and E' of the hooks are similarly
angled.
In the fully closed position of FIG. 5, the curved surface of the
head and the recess, and the additional depth 11 of the recess
coact to permit a rolling of bearing-like action between the
interengaging head and the groove insuring airtightness and
preventing inadvertent disengagement and consequent opening of the
bag.
In addition to the materials above recited with respect to the
eliminations of the bag walls, materials such as PP, nylon,
polyester, polycarbonate, etc. obtain a wall which is extremely
tough and strong and may be very difficult to open with the
fingertips due to the high elastic resistance of each layer. The
other engaging air-excluding rib members aid in the opening
function as well as providing an air-excluding seal themselves.
When the bag is to be opened, the operator pulls apart the upper
flanges and the rib members first separate providing thumb gripping
surfaces to aid in disengaging the rib and groove elements.
The rib members are arranged so that their mechanical strength is
larger than that of the film between them. In other words, the rib
members are formed thicker than the wall thickness of the film in
the recess between the rib members. In the alternative, the rib
members may be made of a material which is harder than that which
constitutes the film of the bag walls in the recess between
them.
Since the ridges are constructed to have stronger tear resistance
than the layer of film in the recessed portion between them, the
tearing force applied for opening purposes to the recessed portion
between the rib members is inhibited by the ribs from advancing in
other directions. Thus, the entire tearing force in opening the bag
is concentrated on the recessed portion to permit easy opening
along the rib walls. Thus, the desired opening of the pouch can
easily be effected by simple finger operation as shown in FIG. 2b
with no need or using a scissors, knife or other such opening
means.
Thus, it will be seen that I have provided an improved fastener
which meets the objectives and advantages above set forth and which
provides an improved, more effective pouch and fastener.
* * * * *