Note: Descriptions are shown in the official language in which they were submitted.
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PLASTIC CLOSURE FOR
PLASTIC BEVERAGE BOTTLE
This invention relates in general to new and
useful improvements in closures for containers, and
more specifically to a closure which is formed of plastics
material and is particularly adapted for use in closing a
beverage bottle also formed of plastics material
There have already been developed metal closures
which when applied to beverage bottles formed of plastics
10 material will form a seal therewith. However, in conjunc-
tion with metal closures it is still necessary to provide
a sealing material within the metal closure and for the
sealing material to engage the axial extremity of the
bottle lip.
It is also known to form container closures of
plastics material as is clearly disclosed in the U.S.
patent No. 3,893,583 to McLaren of July 8, 1975. Further,
the closure of the McLaren patent is provided with a tamper
indicating band which is so related to the closure that the
20 closure cannot be removed from the associated container
without removal of the band.
In accordance with this invention it is proposed
to provide a closure for a beverage bottle which closure is
formed of plastics material and is particularly configurated
to cooperate with a plastics material bottle to form a
lasting seal therewith which is sufficient to resist high
internal pressures within the bottle even when the bottle
is provided with a mouth having an internal diameter on the
order of 38 mm. There have been developed in recent years
formed of plastics material which have the necessary prop-
erties for forming a container for beverages under pressure.
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The bottle, while the plastics material there~f is quite
hard, has posed a problem in the efficient application of
closures thereto. Such bottles are normally formed of
polyethyleneterephthalate or other FDA-approved plastics
material. In accordance with this invention, it is pro-
posed to provide a closure which is formed of plastics
material and is so constructed wherein not only may it be
efficiently molded at a comparatively low cost, but also
it may be readily applied to existing plastic bottles at
a greatly reduced application pressure.
One of the features of the invention is the seal
which is effected between the closure and the lip of the
bottle. The closure is provided internally with a wedge-
shaped portion which engages the exterior of the lip of
the bottle, and when applied, radially inwardly compresses
and deflects the lip of the bottle with the seal between
the closure of the bottle being between the exterior sur-
face of the lip and the wedge surface of the closure. No
seal is formed between the axial end of the lip and the
end panel of the closure, thereby eliminating the need for
the customary sealing ring or layer applied to the end
panel of the closure cap.
Another feature of the invention is that the neck
finish of the plastics material bottle may be formed with a
tapered lip, the lip tapering to almost a point at its axial
end, thereby effecting a savings in material in the forma-
tion of the bottle.
Another feature of the invention is that the end
panel of the closure is made sufficiently thick to retain
internal pressures and provide a barrier to resist the
permeation of oxygen or carbon dioxide, but at the same
time sufficientl~ thin so as to axially deform, drawing
the wedge surface radially inwardly to tighten the seal
by way of the pressure within the bottle. This continuous
drawing in of the wedge suxface of the closuxe overcomes
deficiencies of seals which frequently lose their sealing
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efficiency after a time due to the inherent creep proper-
tles of the plastics material, with a corresponding in-
crease of torque necessary to remove the closure.
A further feature of the closure is the provision
of a retaining ring which is permanently interlocked with
the bottle so as to prevent blow-off of the closure when
opening the bottle under high pressure conditions. Associ-
ated with the retaining ring and disposed between the retain-
ing ring and the skirt of the closure is a removable tear
strip which has the dual function of making the closure
tamper-proof and aiding in the retention of the closure in
place against high internal pressures within the bottle.
In particular, there is provided a pressurized con-
tainer and closure therefor combination, the container in-
cluding a neck terminating in a lip defining a mouth, theneck having an external finish, the container and the closure
each being formed of a resiliently deformable plastics mater-
ial, the closure cap including an end panel and a depending
skirt, the skirt having an inner surface including an upper
portion and a lower portion, the lower skirt inner portion
having thereon closure means in interlocking engagement with
the neck finish for retaining the closure on the neck, and
the upper skirt inner surface portion defining an inwardly
and upwardly sloping wedge surface means for engaging the
container lip and forming a resilient seal therewith, the
container lip being radially inwardly deformable upon forma-
tion of the resilient seal, the lip being thin as compared
to the wall thickness of other portions of the neck finish
with the neck finish forming the lip having a tapered outer
surface, the resilient seal being a continuous area of con-
tact between the wedge surface means and the lip, the area
of contact being the sole seal between the closure and the
pressurized container.
Further, there is provided a pressurized container
and closure therefor combination, the container including a
neck terminating in a lip defining a mouth, the neck having
an external finish, the container and the closure each being
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formed of a resiliently deformable plastics material, the
closure cap including an end panel and a depending skirt,
the skirt having an inner surface including an upper portion
and a lower portion, the lower skirt inner portion having
thereon closure means in interlocking engagement with the
neck finish for retaining the closure on the neck, and the
upper skirt inner surface portion defining an inwardly and
upwardly sloping wedge surface means for engaging the con-
tainer lip and forming a resilient seal therewith, the end
panel within the inner outline of the wedge surface means
being of a thickness wherein the end panel is deformed
axially and draws the wedge surface means radially inwardly
to increase the radial pressure of the seal.
With the above and other objects in view that will
hereinafter appear, the nature of the invention will be more
clearly understood by reference to the following detailed
description, the appended claims, and the several views il-
lustrated in the accompanying drawings.
IN THE DRAWINGS:
Figure 1 is a front elevational view of the clo-
sure applied to a bottle, only the neck portion of the
bottle being shown.
Figure 2 is an enlarged fragmentary vertical
sectional view taken through the closure and neck finish
of the bottle generally along the line 2-2 of Figure 1.
E'igure 3 is an enlarged fragmentary sectional
view taken through the closure and neck portion of the
bottle, showing the closure deformed under pressure.
Figure 4 is an enlarged fragmentary sectional
view similar to Figure 3 showing the closure and bottle
in partially assembled relation.
E'igure 5 is a top plan view of the closure and
shows further the details thereof.
Figure 6 is a rear perspective view of the
closure.
Figure 7 is another rear perspective view of
the closure with the tear strip removed and the sealing
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portion of the closure pivoted relative to the retaining
ring to an opened position.
Figure 8 is an enlarged fragmentary elevational
view with parts broken away and shown in section of the
neck of the bottle.
Referring now to the drawings in detail, it will
be seen that the closure is generally identified by the
numeral 10 and the container is generally identified by
the numeral 12. The closure 10 is in the form of a cap
and includes an end panel 14 and a depending skirt 16.
Spaced axially from the skirt 16 is a retaining ring 20
which is permanently secured to the lower edge of the
skirt by means of a retaining band or hinge 22. Disposed
coplanar with the retaining band 22 and positioned between
the retaining ring 20 and the lower edge of the skirt 16 is
a tear strip 24. The tear strip 24 is connected to the
skirt 16 by a weakening line 26 and to the retaining ring
20 by a weakening line 28. One end of the tear strip 24
is provided with a projecting lug 30 which extends radially
outwardly of the cap or closure 10 and which may be readily
gripped to facilitate the tearing out of the tear strip 24.
As is clearly shown in Figures 1 and 6, the tear
strip 24 extends only partially about the circumference of
the cap 10 and both ends thereof are spaced from the retain-
ing band 22. Between the retaining band 22 and the ends of
the tear strip 24, the retaining ring 20 has upwardly pro-
jecting portions 32 which are disposed immediately adjacent
the skirt 16 and are connected thereto by lines of weaken-
ing 34 (Figure 6).
At this time it is to be understood that the
closure 10 has an interlocking engagement with the contain-
er 12 and is removed by first tearing out the tear strip 24
and then lifting the front part of the skirt 16 by means of
a lug 36 which is integrally connected to a lower forward
part of the skirt 16. The lug 36 is stiffened by a rib
38.
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When the upper portion of the closure 10 is
separated from the container 12, it remains attached there-
to by way of the retaining band 20 and hinges relative to
the retaining band 20 in the manner best shown in Figure 7.
As the upper part of the closure is raised, the skirt 16
separates from the retaining band ~0 by the gradual rupture
of the lines of weakening 34.
The closure 10 is particularly adapted for use
with a container 12 in the form of a beverage bottle which
io is intended to have packaged therein beverages, such as
soft drinks, under pressure. The neck finish of the con-
tainer 12 is best illustrated in Figure 8 and includes a
cylindrical neck portion 40 with a constant diameter
throat 42. Above the cylindrical neck 40 the neck finish
includes a lower shoulder 44 which is formed on the under-
side of a tapered exterior portion 46 which, together with
an upper tapered portion 48, defines a further shoulder 50.
It is particularly pointed out here that the upper tapered
portion 48 defines a radially inwardly and upwardly sloping
sealing surface 52 and that the thickness of the tapered
upper portion 48 approaches zero at the lip end of the neck
finish.
The formation of the neck finish of the container
12 so as to be tapered results in a savings of material.
It is pointed out here at this time that the
present containers which are in the form of carbonated
beverage bottles are formed of suitable plastics material
with the most widely used plastics material being poly-
ethylene terephthalate, which is a relatively hard material
in its molded state. It is proposed to form the closure
cap of plastics material which is softer than the plastics
material of the container 12, and it has been found that
polyethylene or other suitable plastics material may be
used in the formation of the closure.
Returning now to Figure 2, it will be seen that
the lower portions of the tear strip and the retaininy band
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are of a lesser radial thickness than the upper portion
of the retaining ring 20 so that an upwardly facing should-
er S4 is formed on the retaining ring 20 for engagement
with the shoulder 44 to hold the retaining ring 20 on the
container at all times.
It will also be seen that the internal configura-
iion of the lower portion of the skirt 16 is such as to
define an upwardly and radially inwardly directed shoulder
56 which is interlocked beneath the shoulder 50. The inter-
locking shoulders 50, 56 form the primary means for retain-
ing the closure 10 on the con~ainer 12. However, until such
time as the tear strip 24 is removed, the retaining ring 20
also aids in the retention of the closure on the container.
Most particularly, it is to be noted that the
upper part of the inner surface of the skirt 16 is tapered
upwardly and radially inwardly to define a wedge surface
58. This wedge surface 58 engages the lip portion of the
neck finish of the container 12 and forms a seal therewith.
It will be seen that the wedge surface 58 engages the tap-
ered surface 52 and forcibly deflects the extreme upperlip portion of the closure 12 radially inwardly with a
seal 60 being formed between the wedge surface 58 and the
tapered surface 52. It will be seen that the deflection
of the lip portion of the neck finish of the container 12
provides a resilient sealing effect and therefore the seal
is maintained over a period of time.
It is acknowledged that plastics materials have
a tendency to creep over a period of time and that under
certain conditions the plastics material of the lip por-
tion of the container 12 will have a tendency to expanddue to the internal pressure in the bottle, and therefore
the pressure engagement in the area of the seal will in-
crease. At the same time, because the closure 10 is formed
of a resilient deformable plastics material, and by forming
the end panels 14 of a thinness wherein it will deflect
axially under pressure within the container, it will be
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seen that the upper part of the skirt 16 will be constantly
drawn inwardly so that the wedge surface 58 will always
exert a pressure on the lip portion of the container to
maintain the seal 60. Thus, actually the internal pres-
sure results in a tighter seal as opposed to the normal
condition of the internal pressure acting against any
effective seal being formed.
The closure 10 has a further benefit in that it
may be readily applied to the container 12 without damaging
the container. Existing metal caps require up to 500
pounds axial load for application. This high loading un-
duly stresses the container and fre~uently results in
rupture. Considerably lower axial loads are required to
apply the closure 10, axial loads on the order of 30-40
pounds being possible. This, of course, will greatly re-
duce container rupture during the application of the clo-
sures.
In practical uses, the interlock between the
skirt 16 and the neck finish of the container 12 will be
sufficient to retain the closure cap thereon. However,
if the container is warm or has been shaken prior to open-
ing, there is a pressure bulld-up in the container which
could exceed the holding power of the skirt 16. Under
these conditions, the retaining ring 2n will hold the
closure cap in place. However, when the tear strip 24 is
removed, this releases the retaining ring 20 from the
skirt 16 with the result that the closure cap 10 can, in
such abnormal circumstances, blow off. ~y having the
closure retained with respect to the container at all
times by the retaining ring 20, such blowing off of the
closure will not form a dangerous hazard in that the clo-
sure will merely hinge relative to the retaining band and
will not strike anyone or anything.
It is also pointed out at this time that while
the end panel 14 has a centxal Portion 62 of a reduced
thickness, there is a raised peripheral poxtion 64 Which
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could have suitable lettering either applied thereto or
on the raised portion 64 in the form of molded lettering.
In a like manner, since the periphery of the upper portion
of the skirt 16 is also normally smooth, it may also be
provided with suitable lettering either applied thereto
or molded therewith. The lettering may be utilized either
for instruction purposes or advertising purposes.
It is also to be understood that even with the
tear strip removed the closure is effective for resealing
purposes in that the interlock between the skirt and the
neck finish will maintain the closure in place with the
lip portion of the container deflected in the manner il-
lustrated, and that any retained pressure within the con-
tainer, as normally occurs with carbonated beverages, will
still aid in maintaining the seal. Thus, the closure-
container arrangement provides for extended resealed lift
of carbonated beverages and the like.
Although only a preferred embodiment of the
closure and its relation to a specific container has been
specifically illustrated and described, it is to be under-
stood that minor modifications may be made in either the
closure or the container without departing from the spirit
and scope of the invention as deined in the appended
claims.
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