U.S. patent application number 13/476997 was filed with the patent office on 2014-05-08 for plastic container having a deep-set invertible base and related methods.
The applicant listed for this patent is John Denner, Paul Kelley, David Melrose, Gregory A. Trude. Invention is credited to John Denner, Paul Kelley, David Melrose, Gregory A. Trude.
Application Number | 20140123603 13/476997 |
Document ID | / |
Family ID | 50627256 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140123603 |
Kind Code |
A1 |
Denner; John ; et
al. |
May 8, 2014 |
PLASTIC CONTAINER HAVING A DEEP-SET INVERTIBLE BASE AND RELATED
METHODS
Abstract
A plastic container comprises an upper portion including a
finish defining an opening into the container, a lower portion
including a base defining a standing surface, a sidewall extending
between the upper portion and the lower portion, the sidewall
defining a longitudinal axis, and at least one substantially
transversely-oriented pressure panel located in the lower portion.
The pressure panel is movable between an outwardly-inclined
position and an inwardly-inclined position to compensate for a
change of pressure inside the container. The standing surface
defines a standing plane, and the entire pressure panel is located
between the standing plane and the upper portion of the container
when the pressure panel is in the outwardly-inclined position.
Inventors: |
Denner; John; (York, PA)
; Kelley; Paul; (Wrightsville, PA) ; Melrose;
David; (Mount Eden, NZ) ; Trude; Gregory A.;
(Seven Valleys, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Denner; John
Kelley; Paul
Melrose; David
Trude; Gregory A. |
York
Wrightsville
Mount Eden
Seven Valleys |
PA
PA
PA |
US
US
NZ
US |
|
|
Family ID: |
50627256 |
Appl. No.: |
13/476997 |
Filed: |
May 21, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12964127 |
Dec 9, 2010 |
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13476997 |
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11249342 |
Oct 14, 2005 |
7900425 |
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12964127 |
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13415831 |
Mar 8, 2012 |
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11249342 |
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11704368 |
Feb 9, 2007 |
8584879 |
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13415831 |
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10529198 |
Dec 15, 2005 |
8152010 |
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PCT/NZ03/00220 |
Sep 30, 2003 |
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11704368 |
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10851083 |
May 24, 2004 |
7543713 |
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11704368 |
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10444616 |
May 23, 2003 |
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10851083 |
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10124734 |
Apr 17, 2002 |
6612451 |
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10444616 |
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11432715 |
May 12, 2006 |
7717282 |
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11704368 |
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10363400 |
Feb 26, 2003 |
7077279 |
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PCT/NZ01/00176 |
Aug 29, 2001 |
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11432715 |
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11704318 |
Feb 9, 2007 |
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13415831 |
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11432715 |
May 12, 2006 |
7717282 |
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11704318 |
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10363400 |
Feb 26, 2003 |
7077279 |
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PCT/NZ01/00176 |
Aug 29, 2001 |
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11432715 |
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11704338 |
Feb 9, 2007 |
8127955 |
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13415831 |
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10529198 |
Dec 15, 2005 |
8152010 |
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PCT/NZ03/00220 |
Sep 30, 2003 |
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11704338 |
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11432715 |
May 12, 2006 |
7717282 |
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11704338 |
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10363400 |
Feb 26, 2003 |
7077279 |
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PCT/NZ01/00176 |
Aug 29, 2001 |
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11432715 |
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13284907 |
Oct 30, 2011 |
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13415831 |
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11413583 |
Apr 28, 2006 |
8047389 |
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13284907 |
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10363400 |
Feb 26, 2003 |
7077279 |
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PCT/NZ01/00176 |
Aug 29, 2001 |
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11413583 |
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11413124 |
Apr 28, 2006 |
8381940 |
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10363400 |
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10529198 |
Dec 15, 2005 |
8152010 |
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PCT/NZ03/00220 |
Sep 30, 2003 |
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11413124 |
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10566294 |
Sep 5, 2006 |
7726106 |
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PCT/US04/24581 |
Jul 30, 2004 |
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11413124 |
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60284795 |
Apr 19, 2001 |
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60491179 |
Jul 30, 2003 |
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60551771 |
Mar 11, 2004 |
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Current U.S.
Class: |
53/440 |
Current CPC
Class: |
B65D 1/0284 20130101;
B29C 49/12 20130101; B65B 63/08 20130101; B65D 79/005 20130101;
B65D 1/0276 20130101; B29C 49/06 20130101; B67C 2003/226 20130101;
B65D 2501/0036 20130101; B29C 49/541 20130101; B29C 2049/4892
20130101; B67C 3/045 20130101; B29L 2031/7158 20130101 |
Class at
Publication: |
53/440 |
International
Class: |
B65B 63/08 20060101
B65B063/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2000 |
NZ |
506684 |
Jun 15, 2001 |
NZ |
512423 |
Sep 30, 2002 |
NZ |
521694 |
Claims
1. A method of compensating for vacuum pressure changes within a
container, comprising: hot filling the container with a product;
sealing the container with a closure; cooling the hot filled
container; and repositioning a base wall adjoining a hinge from an
outward extending position to an inward extending position, thereby
reducing the internal pressure of the container, wherein prior to
repositioning, the container is adapted to stand upright on a flat
surface.
2-120. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 12/964,127, filed Dec. 9, 2010, which
is a division of U.S. patent application Ser. No. 11/249,342, filed
Oct. 14, 2005, now U.S. Pat. No. 7,900,425.
[0002] The present application is a continuation-in-part of U.S.
patent application Ser. No. 13/415,831 (the '831 application).
[0003] The '831 application is a continuation-in-part of U.S.
patent application Ser. No. 11/704,368 (the '368 application and
published as US2008/0047964). The '368 application is a
continuation-in-part of U.S. patent application Ser. No.
10/529,198, filed on Dec. 15, 2005, which is the U.S. National
Phase of International Application No. PCT/NZ2003/000220, filed on
Sep. 30, 2003, which claims priority of New Zealand Application No.
521694, filed on Sep. 30, 2002. The '368 application is also a
continuation-in-part of U.S. patent application Ser. No.
10/851,083, filed on May 24, 2004, which is a continuation-in-part
of U.S. application Ser. No. 10/444,616, filed on May 23, 2003,
which is a continuation-in-part of U.S. application Ser. No.
10/124,734, filed on Apr. 17, 2002, now U.S. Pat. No. 6,612,451,
which claims priority of U.S. Provisional Patent Application No.
60/284,795, filed on Apr. 19, 2001. The '368 application is a also
a continuation-in-part of co-pending U.S. patent application Ser.
No. 11/432,715, filed on May 12, 2006, which is a continuation of
co-pending U.S. patent application Ser. No. 10/363,400, filed on
Feb. 26, 2003, which is the U.S. National Phase of PCT/NZ01/00176,
filed on Aug. 29, 2001, which in turn claims priority to New
Zealand Patent Application No. 506684, filed on Aug. 31, 2000, and
New Zealand Patent Application No. 512423, filed on Jun. 15,
2001.
[0004] This '831 application is also a continuation-in-part of
co-pending U.S. patent application Ser. No. 11/704,318 (the '318
application and published as
[0005] US20070199916). The '318 application is a
continuation-in-part of co-pending U.S. patent application Ser. No.
11/432,715, filed on May 12, 2006, which is a continuation of
co-pending U.S. patent application Ser. No. 10/363,400, filed on
Feb. 26, 2003, which is the U.S. National Phase of PCT/NZ01/00176,
filed on Aug. 29, 2001, which in turn claims priority to New
[0006] Zealand Patent Application No. 506684, filed on Aug. 31,
2000, and New Zealand Patent Application No. 512423, filed on Jun.
15, 2001.
[0007] The '831 application is also a continuation-in-part of
co-pending U.S. patent application Ser. No. 11/704,338 (the '338
application and published as US20070199915). The '338 application
is a continuation-in-part of co-pending U.S. patent application
Ser. No. 10/529,198, filed Dec. 15, 2005, which claims priority of
International Application No. PCT/NZ2003/000220, filed Sep. 30,
2003, which in turn claims priority of New Zealand Patent
Application No. 521694, filed Sep. 30, 2002. The '338 application
is a also a continuation-in-part of co-pending U.S. patent
application Ser. No. 11/432,715, filed on May 12, 2006, which is a
continuation of co-pending U.S. patent application Ser. No.
10/363,400, filed on Feb. 26, 2003, which is the U.S National Phase
of PCT/NZ01/00176, filed on Aug. 29, 2001, which in turn claims
priority to New Zealand Patent Application No. 506684, filed on
Aug. 31, 2000, and New Zealand Patent Application No. 512423, filed
on Jun. 15, 2001.
[0008] The '831 application is also a continuation-in-part of U.S.
patent application Ser. No. 13/284,907, filed Oct. 30, 2011, which
is a continuation of Ser. No. 11/413,583, filed Apr. 28, 2006, now
U.S. Pat. No. 8,047,389, which is a continuation of U.S. patent
application Ser. No. 10/363,400, entitled "Semi-Rigid Collapsible
Container", filed Feb. 26, 2003, now U.S. Pat. No. 7,077,279, which
is a 371 application of PCT/NZ01/00176, filed Aug. 29, 2001, which
claims priority from New Zealand patent application entitled,
"Semi-Rigid Collapsible Container", filed on Aug. 31, 2000,
Application No. 506684; and New Zealand application entitled,"
Semi-Rigid Collapsible Container", filed on Jun. 15, 2001,
Application No. 512423.
[0009] The '831 application is also a continuation-in-part of U.S.
patent application Ser. No. 11/413,124 filed Apr. 28, 2006 (the
'124 application and published as US2006/0255005). The '124
application is also a continuation-in-part of U.S. patent
application Ser. No. 10/529,198, filed on Dec. 15, 2005, which is
the U.S. National Phase of International Application No.
PCT/NZ2003/000220, filed on Sep. 30, 2003, which claims priority of
New Zealand Application No. 521694, filed on Sep. 30, 2002. The
'124 application is also a continuation-in-part of U.S. patent
application Ser. No. 10/566,294, filed on Jan. 27, 2006, which is
the U.S. National Phase of International Application No.
PCT/US2004/024581, filed on Jul. 30, 2004, which claims priority of
U.S. Provisional Patent Application No. 60/551,771, filed Mar. 11,
2004, and U.S. Provisional Patent Application No. 60/491,179, filed
Jul. 30, 2003.
[0010] The contents and disclosures of each of the aforementioned
applications, their publications and patents are incorporated
herein by reference thereto.
BACKGROUND OF THE INVENTION
[0011] 1. Field of the Invention
[0012] The present invention relates generally to a hot-fill
container structure that allows for the removal of vacuum pressure
within the container, and more particularly, to a hot-fill
container structure having an invertible vacuum panel deeply set
into the base of the container. The present invention also relates
to methods of making and processing containers having an invertible
vacuum panel deeply set into the base of the container.
[0013] 2. Related Art
[0014] So called "hot-fill" containers are known in the art.
Plastic containers, such as PET containers, are filled with various
liquid contents at an elevated temperature, typically around
185.degree. F. Once the liquid within the container cools, the
volume of the contained liquid reduces, creating a vacuum within
the container that pulls inwardly on the side and end walls of the
container. This in turn leads to deformation of the plastic
container if it is not constructed rigidly enough to resist the
vacuum forces.
[0015] Typically, vacuum pressures have been accommodated by the
use of s vacuum panels that deflect inwardly under vacuum pressure.
Known vacuum panels are typically located in the container sidewall
and extend parallel to the longitudinal axis of the container, and
flex inwardly under vacuum pressure toward the longitudinal
axis.
[0016] It is also known in the prior art to have a flexible base
region to provide additional vacuum compensation. All such known
prior art containers, however, have substantially flat or inwardly
recessed base surfaces that deflect further inward to compensate
for the vacuum forces. Known flexible base regions have not been
able to adequately compensate for the vacuum forces on their own
(i.e., vacuum panels in the sidewall and/or or other reinforcing
structures are still required).
[0017] Therefore, there remains a need in the art for plastic
containers that overcome the aforementioned shortcomings of the
prior art.
BRIEF SUMMARY OF THE INVENTION
[0018] The present invention relates to a plastic container having
an invertible pressure panel located in the container base. The
pressure panel is movable from an initial, outwardly-inclined
position, to an inverted, inwardly-inclined position, in order to
reduce the volume of the container and accommodate for vacuum
forces within the container. The entire pressure panel is set
deeply into the base of the container, such that no portion of the
pressure panel extends beyond the standing ring, regardless of
whether the pressure panel is in the initial position or the
inverted position. This configuration can allow the container to be
supported by the standing ring regardless of whether the pressure
panel is in the initial position or the inverted position.
[0019] According to one exemplary embodiment, the present invention
relates to a plastic container comprising an upper portion
including a finish defining an opening into the container, a lower
portion including a base defining a standing surface, a sidewall
extending between the upper portion and the lower portion, the
sidewall defining a longitudinal axis, and at least one
substantially transversely-oriented pressure panel located in the
lower portion. The pressure panel can be movable between an
outwardly-inclined position and an inwardly-inclined position to
compensate for a change of pressure inside the container. The
standing surface can define a standing plane, and the entire
pressure panel can be located between the standing plane and the
upper portion of the container when the pressure panel is in the
outwardly-inclined position.
[0020] According to another exemplary embodiment, the present
invention relates to a method of processing a plastic container,
comprising the steps of (a) providing a plastic container having an
upper portion including a finish, a sidewall, a lower portion
including a base defining a standing surface, and a substantially
transversely-oriented pressure panel located in the base; (b)
introducing heated liquid contents into the plastic container with
the pressure panel located in an outwardly-inclined position
entirely between the standing surface and the upper portion; (c)
capping the plastic container; and (d) moving the pressure panel to
an inwardly-inclined position entirely between the standing surface
and the upper portion.
[0021] According to yet another exemplary embodiment, the present
invention relates to a method of blow molding a plastic container,
comprising the steps of (a) enclosing a softened polymer material
within a blow mold defining a mold cavity, the blow mold comprising
at least first and second side mold portions and a base mold
portion; (b) inflating the polymer material within the blow mold to
at least partially conform the polymer material to the blow mold
cavity; and (c) displacing the base mold portion with respect to
the first and second side mold portions to form a transverse
pressure panel deeply set within a base portion of the plastic
container.
[0022] Further objectives and advantages, as well as the structure
and function of preferred embodiments will become apparent from a
consideration of the description, drawings, and examples.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The foregoing and other features and advantages of the
invention will be apparent from the following, more particular
description of a preferred embodiment of the invention, as
illustrated in the accompanying drawings wherein like reference
numbers generally indicate identical, functionally similar, and/or
structurally similar elements.
[0024] FIG. 1 is a perspective view of an exemplary embodiment of a
plastic container according to the present invention, shown with a
pressure panel in an initial, outwardly-inclined position;
[0025] FIG. 2 is a side, sectional view of the plastic container of
FIG. 1, shown with the pressure panel in the initial,
outwardly-inclined position;
[0026] FIG. 3 is a side, sectional view of the plastic container of
FIG. 1, shown with the pressure panel in an inverted,
inwardly-inclined position;
[0027] FIG. 4 is a bottom view of the plastic container of FIG.
1;
[0028] FIG. 5 is a perspective view of another exemplary embodiment
of a plastic container according to the present invention, shown
with the pressure panel in the initial, outwardly-inclined
position;
[0029] FIG. 6 is a bottom view of the plastic container of FIG.
5;
[0030] FIG. 7 is a perspective view of a portion of a plastic
container according to yet another exemplary embodiment of the
present invention, shown with the pressure panel in an initial,
outwardly-inclined position;
[0031] FIG. 8 is a bottom view of the plastic container of FIG.
7;
[0032] FIG. 9 is a side, sectional view of a portion of the plastic
container of FIG. 7, shown with the pressure panel in the initial,
outwardly-inclined position;
[0033] FIG. 10 is a side, sectional view of a portion of the
plastic container of FIG. 7, shown with the pressure panel in the
inverted, inwardly-inclined position;
[0034] FIGS. 11A-E schematically illustrate an exemplary method of
processing a plastic container according to the present invention;
and
[0035] FIGS. 12A-C schematically illustrate an exemplary method of
forming a plastic container according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0036] Embodiments of the invention are discussed in detail below.
In describing embodiments, specific terminology is employed for the
sake of clarity. However, the invention is not intended to be
limited to the specific terminology so selected. While specific
exemplary embodiments are discussed, it should be understood that
this is done for illustration purposes only. A person skilled in
the relevant art will recognize that other components and
configurations can be used without departing from the spirit and
scope of the invention. All references cited herein are
incorporated by reference as if each had been individually
incorporated.
[0037] As discussed above, to accommodate vacuum forces during
cooling of the liquid contents within a hot-fill container, plastic
containers have typically included a series of vacuum panels
located around the sidewall and/or in the base portion. The vacuum
panels deform inwardly, and the base deforms upwardly, under the
influence of the vacuum forces. This configuration attempts to
prevent unwanted distortion elsewhere in the container. However,
the container is still subjected to internal vacuum forces. The
sidewalls and base merely provide a suitably resistant structure
against that force. Additionally, the vacuum panels in the sidewall
can undesirably detract from the appearance and feel of the
container, and limit the design possibilities for the
container.
[0038] Typically at a bottling plant, the containers are filled
with a hot liquid and then capped before being subjected to a cold
water spray, resulting in the formation of a vacuum within the
container. The container structure needs to be able to cope with
this vacuum force. U.S. patent application Ser. No. 10/529,198,
filed on Dec. 15, 2005, the entire content of which is incorporated
herein by reference, discloses hot-fill containers that provide for
the substantial removal or substantial negation of the vacuum
pressure within the containers. The disclosed containers include a
transversely-oriented pressure panel located in the container base.
The pressure panel is movable between an initial, outwardly
inclined position, and an inverted, inwardly inclined position, in
order to reduce the volume of the container and accommodate for
vacuum forces within the container. The present invention relates
to additional embodiments of this concept in which the pressure
panel is set deeply into the base of the container, such that no
portion of the pressure panel extends beyond the standing ring,
regardless of whether the pressure panel is in the initial position
or in the inverted position. This configuration can allow the
container to be supported by the standing ring regardless of
whether the pressure panel is in the initial position or the
inverted position.
[0039] Referring to FIGS. 1-4, an exemplary embodiment of a plastic
container 10 according to the present invention is shown. The
container 10 can include an upper portion 12 including a finish 14
that defines an opening into the interior of the container 10. As
shown, the finish 14 can include threads 16 or other structures
adapted to secure a closure (not shown) onto the container 10. The
container 10 can also include a lower portion 18 having a base 20,
and a sidewall 22 extending between the upper portion 12 and the
lower portion 18. The base 20 can define a standing surface 21 that
is substantially flat and adapted to support the container 10 in a
substantially upright position (e.g., with longitudinal axis A
substantially perpendicular to the surface on which container 10 is
resting).
[0040] In the exemplary embodiment shown, the sidewall 22 is
substantially tubular and has a substantially circular transverse
cross-sectional shape. Alternative cross-sectional shapes can
include, for example, an oval transverse cross-section; a
substantially square transverse cross-section; other substantially
polygonal transverse cross-sectional shapes such as triangular,
pentagonal, etc.; or combinations of curved and arced shapes with
linear shapes. As will be understood by one of ordinary skill in
the art, when the container 10 has a substantially polygonal
transverse cross-sectional shape, the corners of the polygon are
typically rounded or chamfered. Although the container 10 is shown
as having reinforcing rings 23 in the sidewall 22, other
embodiments are possible where the sidewall 22 is substantially
devoid of such features (e.g., the sidewall 22 can be smooth like
that of a conventional glass container).
[0041] As best seen in FIG. 4, a portion of the base 20 can include
a plurality of reinforcing ribs 24, however other embodiments with
or without the reinforcing ribs 24 are possible.
[0042] The lower portion 18 of the container 10, and particularly
the base 20, can include a substantially transversely-oriented
pressure panel 26. The pressure panel 26 can be moved between an
outwardly-inclined position (shown in FIGS. 1 and 2) and an
inwardly-inclined position (shown in FIG. 3) in order to reduce the
internal volume of the container 10 and compensate for any vacuum
forces created within the container, for example, during the
filling process. For example, the pressure panel 26 may
substantially remove the internal vacuum that develops within the
container 10 during a hot-fill process once the container 10 has
been hot-filled, capped, and cooled.
[0043] As best seen in the sectional views of FIGS. 2 and 3, the
pressure panel 26 can be deeply set into the container 10 in order
to facilitate standing of the container 10 on its standing surface
21 regardless of whether the pressure panel 26 is located in the
outwardly-inclined position (FIG. 2) or the inwardly-inclined
position (FIG. 3). In other words, the entire pressure panel 26
structure can be located between the plane P of the standing
surface 21 and the upper portion 12 of the container 10 when the
pressure panel 26 is in the outwardly-inclined position (FIG. 2)
and also when the pressure panel 26 is in the inwardly-inclined
position (FIG. 3).
[0044] According to the exemplary embodiment shown in FIGS. 1-4,
the lower portion 18 of the container 10 includes a concave outer
wall portion 30 that extends from the lower end of the sidewall 22
to the standing surface 21. The pressure panel 26 is deeply set
into the lower portion 18 of the container 10 via an inner wall 32
that extends from the standing surface 21 to the pressure panel 26.
In the exemplary embodiment shown, the inner wall 32 is parallel or
nearly parallel to the longitudinal axis A of the container 10,
however, other configurations and/or inclinations of the inner wall
32 are possible. In addition, one of ordinary skill in the art will
know that other configurations besides the inner wall 32 may be
implemented to set the pressure panel 26 deeply into the lower
portion 18. An annular, recessed channel 34 can be provided in or
adjacent the standing surface 21. In the exemplary embodiment
shown, the recessed channel has a substantially square
cross-section, however, other shapes are possible. Channel 34 can
reinforce the standing surface 21 and/or facilitate stacking of
multiple containers on top of one another, depending on the shape
and size of the finish 14 and/or closure.
[0045] In the exemplary embodiment of FIGS. 1-4, the standing
surface 21, inner wall 32, and outer wall 30 are substantially
continuous about the circumference of the container 10 (see FIG.
4). However, as shown in the alternative embodiment of FIGS. 5 and
6, the container 10' can have a standing surface 21', inner wall
32', and outer wall 30' that are discontinuous.
[0046] In order to facilitate movement (e.g., folding) of the
pressure panel 26 between the outwardly-inclined position of FIG. 2
and the inwardly-inclined position of FIG. 3, pressure panel 26 can
include a decoupling or hinge structure 36 that is located between
the inner wall 32 and the pressure panel 26. In the exemplary
embodiment shown, the hinge structure 36 comprises a substantially
flat, non-ribbed region, that is susceptible to folding, however,
other configurations of the hinge structure, such as a crease, are
possible.
[0047] Referring now particularly to FIG. 4, the pressure panel 26
can comprise an initiator portion 40 and a control portion 42. Both
the initiator portion 40 and control portion 42 can comprise part
of the pressure panel 26 that folds when the pressure panel 26 is
moved from its initial position in FIG. 2 to its inverted position
in FIG. 3. The initiator portion 40 can be adapted to move or fold
before the rest of the pressure panel 26 (e.g., before the control
portion 42). In the exemplary embodiment shown, the control portion
42 is at a steeper angle to the standing plane P than the initiator
portion 40, thereby resisting expansion of the pressure panel from
the inverted state (FIG. 3) to the initial state (FIG. 2), for
example, if the container 10 were accidentally dropped.
[0048] In order to maximize the amount of vacuum compensation from
the pressure panel 26, it is preferable for at least the control
portion 42 to have a steep angle of inclination with respect to the
standing plane P. As shown in FIG. 2, the control portion 42 can be
at a first angle .alpha. with respect to the standing plane P.
According to one exemplary embodiment, the first angle .alpha. can
be at least 10 degrees, and preferably is between about 30 degrees
and about 45 degrees. According to this embodiment, the initiator
portion 1 can be at a second angle .beta. with respect to standing
plane P, that is at least 10 degrees less than the first angle
.alpha.
[0049] When the pressure panel is inverted from the outward state
(FIG. 2) to the inward state (FIG. 3), it can undergo an angular
change that is approximately equal to its angle of inclination. For
example, if the control portion 42 is initially set at an angle
.alpha. of about 10 degrees, it will provide an angular change of
approximately 20 degrees. At such a low angle of inclination,
however, it can be difficult to provide an adequate amount of
vacuum compensation in a hot-filled container. Therefore it is
preferable to provide the initiator portion 40 and control portion
42 with steeper angles. For example, with the control portion set
at an angle .alpha. of about 35 degrees, the pressure panel 26 will
undergo an angular change of about 70 degrees upon inversion.
According to this exemplary embodiment, the initiator portion 40
can be set at an angle .beta. of about 20 degrees.
[0050] Referring to FIGS. 7-10, a base portion of a container
according to an alternative embodiment is shown, wherein the
control portion of the pressure panel comprises a substantially
continuous conical area extending around the base. According to
this embodiment, the initiator portion 140 and the control portion
142 are set at a common angle, such that they form a substantially
uniform pressure panel 126. However, initiator portion 140 may
still be configured to provide the least amount of resistance to
inversion of pressure panel 126, such that it still provides an
initial area of folding or inversion. For example, the initiator
portion 140 may have a smaller material thickness than the control
portion 142. According to the embodiment shown in FIGS. 7-10,
initiator portion 140 causes the pressure panel 126 to begin
inversion at its region of widest diameter, near the hinge
structure 136.
[0051] Additional structures may be added to the pressure panel 126
in order to add further control over the inversion process. For
example, the pressure panel 126 may be divided into fluted regions,
as shown in FIGS. 6 and 7. As shown, the fluted regions 145 can be
outwardly convex, and evenly distributed around the container's
longitudinal axis to create alternating regions of greater and
lesser angular inclination. This type of geometry can provide
increased resistance against the panel returning from the inward
position (FIG. 10) to the outward position (FIG. 9), for example,
if the container were dropped. The fluted configuration can also
provide more even distribution of forces on the pressure panel 126.
According to an alternative embodiment, the flutes can be inwardly
concave. Inwardly directed flutes offer less resistance to initial
inverting forces, coupled with increased resistance to reverting
back to the original, outward position. Further details regarding
the pressure panel and fluting are disclosed in co-pending U.S.
patent application Ser. No. 10/529,198, filed on Dec. 15, 2005, the
entire content of which is incorporated herein by reference.
[0052] FIGS. 13 to 15 show another exemplary embodiment of a
container that can be used as described herein. The container
includes an upper portion 1102, shoulder 1104, body 1106 and base
1108. The upper portion 1102 includes an opening into the container
which may be closed and sealed, such as via a screw cap using
thread 1112.
[0053] The container body 1106 in the present example includes ribs
1114 in a first region thereof and panels 1116 in second portions
thereof. Panels 1116 in this example act as vacuum panels as
discussed below and also facilitate gripping of the container by a
consumer, but in other examples may be configured to serve only as
grip panels and not pressure panels. In another example, vacuum
panels may be placed in the container body separately from the
grips or without the grips.
[0054] The container base 1108 includes standing ring or bearing
surface 1118 on which the container rests when in an upright
position. Adjacent the standing ring 1118 is a recess or instep
forming a first wall 1120 which joins pressure panel or second wall
1124 via a hinge structure 1122. An inwardly projecting push-up or
section 1126 is provided in the center of the base 1108. The panel
or second wall 1124 may include creases 1128 as shown which aid
control over the configuration of the panel or second wall 1124 as
it moves between outwardly and inwardly inclined positions.
[0055] The container of FIGS. 13 to 15 is particularly adapted to
hot-fill applications but may be used in other applications where
there are changes in pressure inside the container.
[0056] According to one hot-filling method using the container of
FIGS. 13-15, the container is provided to a filling station with
the second wall 1124 configured as shown in FIGS. 14 and 15. The
container is then filled with hot or heated liquid and sealed, for
example, using a screw cap. As the container cools, contents of the
container (particularly the headspace), contract. This causes the
pressure in the container to drop. Cooling may be accelerated, for
example, by spraying the outside of the container with water.
[0057] To prevent unwanted deformation of the container caused by
the reduction in internal pressure, one or both pressure panels
1116, 1124 are configured to move inwards to reduce the container
volume and increase the internal pressure of the container. In one
example, at least the panels 1116 provided in the container
sidewall are adapted to move inwards through action of the vacuum
force generated inside the container during cooling, and in another
example the panel 1124 is adapted to move inward through action of
the vacuum force generated inside the container during cooling. In
a third example, both move inward, and in a further example, the
container sidewalls are subjected to vacuum force prior to the
base.
[0058] In the present example, panel 1124 is also configured to
move to adjust the container volume. More particularly, panel 1124
is configured to invert about hinge structure 1122 from being
outwardly inclined as shown in FIGS. 14 and 15 to being inwardly
inclined (not shown).
[0059] Inversion of the panel 1124 may be initiated by engagement
of a pusher or other external mechanical force against the base
1108, preferably the centrally located push-up 1126 of the base
1108. Additionally or alternatively, the panel 1124 may include an
initiator portion that is configured to initiate or cause the rest
of the panel to move between the outwardly and inwardly inclined
positions. The initiator portion may reduce or obviate the need for
a pusher, providing for movement of the panel 1124 due to the
forces generated by the pressure differential between the inside
and outside of the container. To this end, the initiator portion
may have a lower angle of inclination than other portions of the
panel 1124 relative to the standing plane formed by the standing
ring 1118.
[0060] According to preferred embodiments, opposing vacuum panels
1116 are subjected to vacuum force prior to repositioning of the
base. More preferably, the vacuum panels 1116 move inwards prior to
movement of the second wall or panel 1124 to the inwardly inclined
position. Other methods of using containers as described herein can
also be used with the container of FIGS. 13-15.
[0061] It will be noted that the instep or first wall 1120 is
configured so as to elevate the panel 1124 and other portions of
the base 1108 above the standing ring 1118 when the panel 1124 is
outwardly inclined. Such a configuration provides improved
container stability during the filling operations. However, the
instep or first wall 1120 may be recessed to a lesser extent such
that a portion of the base extends below the standing ring 1118
when the panel 1124 is outwardly inclined. As will be appreciated,
this will mean that different portions of the container base 1108
act as the standing ring depending on whether the panel or second
wall 1124 is inwardly or outwardly inclined.
[0062] The container shown in FIGS. 13 to 15 may also be used in
pasteurisation processes. According to an example such process, the
container is filled with the panel 1116, 1124 in the inward
position and then sealed. The container and its contents are then
heated, causing an increase in internal pressure. As a result of
this the panels 1116, 1124 move to an outward position. After the
heating stage of the pasteurisation process is completed and the
container is cooled, the panels 1116, 1124 preferably revert to the
inwardly inclined position.
[0063] According to preferred embodiments, different stages of the
filling and/or pasteurisation processes may be performed at
different stations within a filling or processing facility. To this
end, the container may be conveyed in between stages or during a
particular stage depending on system requirements and
preferences.
[0064] FIGS. 16 and 17 show a container according to another
embodiment. Many of the features of this embodiment are the same or
substantially the same as those of the embodiment of FIGS. 13 to 15
and like references have been used to aid clarity. Only features
that differ from the embodiment of FIGS. 13 to 15 will be
described.
[0065] As shown in FIGS. 16 and 17, the container of this
embodiment includes first and second panels 1116 on two opposing
faces of the sidewall thereof, at least one of which is a vacuum
panel.
[0066] FIGS. 18 and 19 show another embodiment of a container that
is substantially identical to the container of FIGS. 16 and 17 and
again only points of difference will be described.
[0067] Notably, in the embodiment of FIGS. 18 and 19, the first
wall or instep 1120 is inclined at a lesser angle than in the
embodiment of FIGS. 16 and 17. As will be appreciated, other angles
of inclination may also be used.
[0068] The operation or preferred use of the containers of FIGS. 16
and 17, and FIGS. 18 and 19, is substantially identical to that
described in relation to the embodiment of FIGS. 13 to 15.
[0069] Referring to FIGS. 11A-11E, an exemplary method of
processing a plastic container according to the present invention
is shown. Prior to processing, the container 10 may be formed
(e.g., blow molded) with the pressure panel 26 in the
inwardly-inclined position. According to this embodiment, a force
can be applied to the pressure panel 26 in order to move the
pressure panel 26 into the outwardly-inclined position. For
example, as shown in FIGS. 11A and 11B, a first mechanical pusher
50 can be introduced through the opening in the container finish 14
and forced downwardly on the pressure panel 26 in order to move it
to the outwardly-inclined position (shown in FIG. 11C). One of
ordinary skill in the art will know that other types of mechanical
or other forces can alternatively be used to move the pressure
panel 26 into the outwardly-inclined position. Alternatively, the
container 10 can be initially formed with the pressure panel 26
located in the outwardly-inclined position.
[0070] Referring to FIG. 11C, the container 10 can be filled with
liquid contents when the pressure panel 26 is located in the
outwardly-inclined position. Particularly, the container 10 can be
"hot-filled" with the liquid contents at an elevated temperature,
for example, 185.degree. C. As shown in FIG. 11C, the liquid
contents can be introduced into the container 10 via a filling
nozzle 52 inserted through the opening in the container finish 10,
although one of ordinary skill in the art will know that any number
of known filling devices and techniques can be implemented.
According to an alternative embodiment, the first mechanical pusher
50 and the filling nozzle 52 can be the same instrument.
[0071] Referring to FIG. 11D, once the container 10 has been filled
to the desired level, the filling nozzle 52 can be removed, and a
cap 54 can be applied to the container finish 14. Any number of
capping techniques and devices known in the art can be used to
apply the cap 54 to the container finish 14. Next the container 10
can be cooled, for example, by spraying the container 10 with cool
water, or alternatively, by leaving the container 10 in ambient
conditions for a sufficient amount of time. As the container 10 and
its contents cool, the contents tend to contract. This volumetric
change inside the sealed container 10 can create a vacuum force
within the container 10.
[0072] In order to alleviate all or a portion of the vacuum forces
within the container 10, the pressure panel 26 can be moved from
the outwardly-inclined position of FIG. 11D to the
inwardly-inclined position of FIG. 11E. For example, following
filling, capping, and cooling of the container 10, an external
force can be applied to the pressure panel 26, for example, by a
second mechanical pusher 56, as shown in FIG. 11D. Alternatively,
the pressure panel 26 can be moved by the creation of relative
movement of the container 10 relative to a punch or similar
apparatus, in order to force the pressure panel 26 into the
inwardly-inclined position. Alternatively, the pressure panel 26
can invert to the inwardly-inclined position under the internal
vacuum forces within the sealed container 10. For example, all or a
portion of the pressure panel 26 (e.g., the initiator portion) can
be made flexible enough to cause the pressure panel 26 to invert
under the internal vacuum forces.
[0073] The inversion of the pressure panel 26 from the
outwardly-inclined position to the inwardly-inclined position
reduces the internal volume of the container 10, and thereby
increases the pressure inside the sealed container 10. This can
alleviate any vacuum created within the container 10 due to the
hot-fill process. This can also remedy any deformation of the
container 10 that was caused as a result of the internal
vacuum.
[0074] As shown in FIGS. 11A-E, the entire pressure panel 26 is
above the plane P of the standing surface 21 (see FIG. 11C) of the
container 10. As a result of this configuration, the containers 10
according to the present invention can be stored, transported, and
capped/filled, etc., all while standing on the standing surface 21.
This can eliminate the need for any adapters or other devices to
stabilize the container 10 in the upright position. This can also
make the containers 10 of the present invention more readily
adapted for use with conventional, existing container transports,
capping and filling stations, and storage facilities.
[0075] Referring to FIGS. 12A-C, an exemplary method of blow
molding a plastic container according to the present invention is
shown. Referring to FIG. 12A, the method includes enclosing a
softened polymer material (such as PET, PEN, PP, blends thereof,
and other suitable materials known in the art) within a blow mold.
In the exemplary embodiment shown, the polymer material comprises a
plastic container preform 60. However, according to an alternative
embodiment, the polymer material can comprise a tube of extruded
polymer material, for example, as used in the known process of
"extrusion blow molding."
[0076] The blow mold can comprise two or more side mold portions
62, 64, and a base mold portion 66. The side mold portions 62, 64
can move from an open position (not shown) in which the side mold
portions are separated from one another, to a closed position,
shown in FIGS. 12A-C. In the closed position, shown, the side mold
portions 62, 64 define a mold cavity 68 having an open bottom. The
mold cavity 68 corresponds to the shape of a plastic container to
be molded therein. The base mold portion 66 is located in the open
bottom region of the mold cavity 68 and is movable with respect to
the side mold portions 62, 64 in the vertical direction (as viewed
in FIGS. 12A-C) between the retracted position shown in FIGS. 12A
and 12B, and the extended position shown in FIG. 12C. Mechanical,
pneumatic, hydraulic, or other means known in the art can be
implemented to move the base mold portion 66 between the retracted
and extended positions.
[0077] A stretch rod 70 can be inserted into the neck portion of
the softened preform 60, and can be used to stretch or elongate the
preform 60. Air or another medium can be expelled from the stretch
rod 70 or other device to at least partially inflate the preform 60
into conformity with the mold cavity 68. Preferably, the preform 60
is inflated into substantially complete conformity with the mold
cavity 68 while the base mold portion 66 is in the retracted
position, as shown in FIG. 12B. This can eliminate the need for the
polymer material to expand deeply into tight corners, narrow
spaces, etc., that are associated with the deeply-set pressure
panel of the present invention. This can avoid resultant thin or
weak spots in the formed container.
[0078] While the polymer material is still in a softened state, the
base mold portion 66 can be displaced upwardly into the mold cavity
68 to form a transverse pressure panel deeply set within the base
portion of the plastic container (see, for example, the base 20 and
pressure panel 26 of FIGS. 1-4). Air can continue to be expelled
into the mold cavity during displacement of the base mold portion
66 to the extended position, or alternatively, the supply of air
can be turned off. Referring to FIGS. 1-4, by "deeply set" it is
meant that the pressure panel 26 is located entirely between the
standing plane P and the upper portion 12 of the container when the
pressure panel 26 is in the outwardly-inclined position (FIG. 2)
and when it is in the inwardly-inclined position (FIG. 3). In the
exemplary embodiment of FIGS. 12A-C, the base mold portion 66 moves
substantially along the longitudinal axis of the plastic container
being formed in the mold cavity 68, however, other orientations are
possible.
[0079] Once the plastic container has been formed in the mold
cavity 68, the base mold portion 66 can return to the retracted
position, and the side mold portions 62, 64 can separate to release
the formed container.
[0080] By utilizing the blow molding method of the present
invention, it is possible to initially form the general container
shape with a generally flat bottom portion, and then deflect the
bottom upwardly at orientation temperature. As a result, the
container base and deeply-set pressure panel can be of improved
material thickness and uniformity. In addition, the base and
pressure panel can be multi-axially stretch oriented to provide
increased strength without the attendant thinness or weakness at
the heel portion of the bottle.
[0081] The base of the plastic container according to the present
invention is preferably crystallized to some extent. Some degree of
crystallinity and/or biaxial orientation can be achieved normally
during the blow molding process. However, crystallization can be
promoted through heat setting of the container. For example, the
walls and base of the mold can be held at an elevated temperature
to promote crystallization. When the container is heat set at a
temperature of about 180.degree. F., the container sidewalls, base,
pressure panel, etc., can be typically crystallized to about 20%.
This degree of crystallinity is typical for a blow molding process
and does not represent a significant amount of heat setting or
increased crystallinity or orientation, as compared with a
typically prepared container. However, the properties of the base
and pressure panel of the present invention can be advantageously
enhanced by heat setting the container, and particularly the base
and pressure panel, at ever higher temperatures. Such temperatures
can be, for example, greater than 250.degree. F. and can be
325.degree. F. or even higher. When these elevated heat set
temperatures are utilized, crystallinity can be increased to
greater than 20% or 25% or more. One drawback of increasing
crystallinity and biaxial orientation in a plastic container is
that this process introduces opacity into the normally clear
material. However, unlike bases in prior art containers, which can
require a crystallinity of 30% or more, utilizing crystallinities
of as low as 22-25% with a base structure according to the present
invention can achieve significant structural integrity, while
maintaining the substantial clarity of a base that is preferred by
manufacturers, packagers and consumers.
[0082] U.S. Pat. Nos. 4,465,199; 3,949,033; 4,378,328; and
5,004,109, all of which are incorporated herein by reference,
disclose further details relating to blow molding methods utilizing
displaceable mold portions. The methods disclosed in these
references can also be implemented to form plastic containers
according to the present invention. According to an alternative
embodiment of the invention, the plastic container can be removed
from the blow mold prior to forming the deeply-set pressure panel.
Outside of the mold, the pressure-panel and related structure(s)
can be formed in the base of the plastic container using a mandrel
or similar device. U.S. Pat. No. 4,117,062, the entire content of
which is incorporated herein by reference, provides further details
on this type of post-mold processing.
[0083] The embodiments illustrated and discussed in this
specification are intended only to teach those skilled in the art
the best way known to the inventors to make and use the invention.
Nothing in this specification should be considered as limiting the
scope of the present invention. All examples presented are
representative and non-limiting. The above-described embodiments of
the invention may be modified or varied, without departing from the
invention, as appreciated by those skilled in the art in light of
the above teachings. It is therefore to be understood that, within
the scope of the claims and their equivalents, the invention may be
practiced otherwise than as specifically described.
* * * * *