U.S. patent application number 12/575511 was filed with the patent office on 2011-04-14 for plastic container having improved flexible panel.
This patent application is currently assigned to GRAHAM PACKAGING COMPANY, L.P.. Invention is credited to Travis A. Hunter, Raymond A. Pritchett, JR., Anthony J. Schlies, Jana M. Zeigler.
Application Number | 20110084046 12/575511 |
Document ID | / |
Family ID | 43382368 |
Filed Date | 2011-04-14 |
United States Patent
Application |
20110084046 |
Kind Code |
A1 |
Schlies; Anthony J. ; et
al. |
April 14, 2011 |
PLASTIC CONTAINER HAVING IMPROVED FLEXIBLE PANEL
Abstract
A plastic container that is adapted for adjustment to internal
volumetric changes such as those that typically occur during the
hot fill process includes a container body defining an internal
space. The container body has a sidewall that is shaped to define
at least one flexible panel. The flexible panel has a central
longitudinal axis, an upper portion, a lower portion and a central
portion. The central portion of the flexible panel has a width that
is greater than a respective width of at least one of the upper and
lower portions. The flexible panel is substantially flat as viewed
in a longitudinal cross-section taken along the central
longitudinal axis. Additionally, the central portion has a
transverse radius of curvature that is greater than a transverse
radius of curvature of at least one of the upper portion and said
lower portion. Because the central portion represents the maximum
width of the flexible panel, the efficiency of vacuum uptake is
maximized with respect to conventional vacuum panels that are
substantially flat in longitudinal cross-section.
Inventors: |
Schlies; Anthony J.; (York,
PA) ; Pritchett, JR.; Raymond A.; (Brogue, PA)
; Hunter; Travis A.; (Hallam, PA) ; Zeigler; Jana
M.; (Erwin, TN) |
Assignee: |
GRAHAM PACKAGING COMPANY,
L.P.
York
PA
|
Family ID: |
43382368 |
Appl. No.: |
12/575511 |
Filed: |
October 8, 2009 |
Current U.S.
Class: |
215/381 ;
215/382; 220/666; 220/672 |
Current CPC
Class: |
B65D 1/0246 20130101;
B65D 1/0276 20130101; B65D 2501/0036 20130101 |
Class at
Publication: |
215/381 ;
215/382; 220/666; 220/672 |
International
Class: |
B65D 1/02 20060101
B65D001/02; B65D 90/02 20060101 B65D090/02 |
Claims
1. A plastic container that is adapted for adjustment to internal
volumetric changes, comprising: a container body defining an
internal space, said container body having a sidewall comprising at
least one flexible panel defining a central longitudinal axis, said
flexible panel having an upper portion, a lower portion and a
central portion; said central portion of said flexible panel having
a width that is greater than a respective width of at least one of
said upper and lower portions; and wherein said flexible panel is
substantially flat as viewed in a longitudinal cross-section taken
along said central longitudinal axis.
2. A plastic container according to claim 1, wherein said flexible
panel is substantially oval-shaped as viewed in side elevation.
3. A plastic container according to claim 1, wherein said flexible
panel is convexly curved.
4. A plastic container according to claim 1, wherein said central
portion has a transverse radius of curvature that is greater than a
transverse radius of curvature of at least one of said upper
portion and said lower portion.
5. A plastic container according to claim 1, wherein said central
portion has a width that is greater than respective widths of both
said upper portion and said lower portion.
6. A plastic container according to claim 1, wherein said flexible
panel is elongated along said central longitudinal axis.
7. A plastic container according to claim 1, wherein said central
portion of said flexible panel has a longitudinal center point, and
a first transverse radius of curvature taken through said
longitudinal center point, and wherein said first transverse radius
of curvature is a maximum transverse radius of curvature within
said flexible panel.
8. A plastic container that is adapted for adjustment to internal
volumetric changes, comprising: a container body defining an
internal space, said container body having a sidewall comprising at
least one flexible panel defining a central longitudinal axis, said
flexible panel having an upper portion, a lower portion and a
central portion; said central portion of said flexible panel having
a width that is greater than a respective width of at least one of
said upper and lower portions; and wherein said central portion has
a transverse radius of curvature that is greater than a transverse
radius of curvature of at least one of said upper portion and said
lower portion.
9. A plastic container according to claim 8, wherein said flexible
panel is substantially oval-shaped as viewed in side elevation.
10. A plastic container according to claim 8, wherein said flexible
panel is convexly curved.
11. A plastic container according to claim 8, wherein said central
portion has a width that is greater than respective widths of both
said upper portion and said lower portion.
12. A plastic container according to claim 8, wherein said flexible
panel is elongated along said central longitudinal axis.
13. A plastic container according to claim 8, wherein said central
portion of said flexible panel has a longitudinal center point, and
a first transverse radius of curvature taken through said
longitudinal center point, and wherein said first transverse radius
of curvature is a maximum transverse radius of curvature within
said flexible panel.
Description
BACKGROUND OF THE INVENTION
[0001] 1.Field of the Invention
[0002] This invention relates generally to the field of plastic
containers, and more particularly to plastic containers that are
designed to accommodate volumetric expansion and contraction such
as that inherent to the hot-fill packaging process or to packaging
applications where internal pressurization is anticipated.
[0003] 2. Description of the Related Technology
[0004] Many products that were previously packaged using glass
containers are now being supplied in plastic containers, such as
containers that are fabricated from polyesters such as polyethylene
terephthalate (PET).
[0005] PET containers are typically manufactured using the stretch
blow molding process. This involves the use of a preform that is
injection molded into a shape that facilitates distribution of the
plastic material within the preform into the desired final shape of
the container. The preform is first heated and then is
longitudinally stretched and subsequently inflated within a mold
cavity so that it assumes the desired final shape of the container.
As the preform is inflated, it takes on the shape of the mold
cavity. The polymer solidifies upon contacting the cooler surface
of the mold, and the finished hollow container is subsequently
ejected from the mold.
[0006] Hot fill containers are designed to be used with the
conventional hot fill process in which a liquid or semi-solid
product such as fruit juice, sauce, salsa, jelly or fruit salad is
introduced into the container while warm or hot, as appropriate,
for sanitary packaging of the product. After filling, such
containers undergo significant volumetric shrinkage as a result of
the cooling of the product within the sealed container. Hot fill
type containers accordingly must be designed to have the capability
of accommodating such shrinkage. Typically this has been done by
incorporating one or more vacuum panels into the side wall of the
container that are designed to flex inwardly as the volume of the
product within the container decreases as a result of cooling.
[0007] Typically, the vacuum panel regions of conventional hot fill
containers are characterized by having surfaces that are designed
to deflect inwardly when the product within the sealed container
undergoes shrinkage. The amount of volumetric contraction, also
referred to as vacuum uptake, that can be provided by a
conventional vacuum panel is limited by the size of the panel. The
design of such containers is often influenced by the aesthetic
preferences of manufacturers, which in some instances can limit the
size of the vacuum panels to the extent that makes it difficult or
impossible to achieve the necessary vacuum uptake capacity.
[0008] A need therefore exists for an improved vacuum panel
configuration that achieves a maximal amount of vacuum uptake
capacity in relation to the size of the vacuum panel.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an object of the invention to provide a
plastic container having an improved vacuum panel configuration
that achieves a maximal amount of vacuum uptake capacity in
relation to the size of the vacuum panel.
[0010] In order to achieve the above and other objects of the
invention, a plastic container according to a first aspect of the
invention that is adapted for adjustment to internal volumetric
changes such as those that occur during the hot fill process
includes a container body defining an internal space. The container
body has a sidewall that is shaped to define at least one flexible
panel. The flexible panel has a central longitudinal axis, an upper
portion, a lower portion and a central portion. The central portion
of the flexible panel has a width that is greater than a respective
width of at least one of the upper and lower portions. The flexible
panel is substantially flat as viewed in a longitudinal
cross-section taken along the central longitudinal axis.
[0011] A plastic container according to a second aspect of the
invention is adapted for adjustment to internal volumetric changes
such as those that occur during the hot fill process includes a
container body defining an internal space. The container body has a
sidewall that is shaped to define at least one flexible panel. The
flexible panel has a central longitudinal axis, an upper portion, a
lower portion and a central portion. The central portion of the
flexible panel has a width that is greater than a respective width
of at least one of the upper and lower portions. The central
portion has a transverse radius of curvature that is greater than a
transverse radius of curvature of at least one of the upper portion
and said lower portion.
[0012] These and various other advantages and features of novelty
that characterize the invention are pointed out with particularity
in the claims annexed hereto and forming a part hereof. However,
for a better understanding of the invention, its advantages, and
the objects obtained by its use, reference should be made to the
drawings which form a further part hereof, and to the accompanying
descriptive matter, in which there is illustrated and described a
preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a front elevational view of a plastic container
that is constructed according to a preferred embodiment of the
invention;
[0014] FIG. 2 is a side elevational view of the plastic container
that is depicted in FIG. 1;
[0015] FIG. 3 is a cross-sectional view taken along lines 3-3 in
FIG. 1;
[0016] FIG. 4 is a cross-sectional view taken along lines 4-4 in
FIG. 2;
[0017] FIG. 5 is a cross-sectional view taken along lines 5-5 in
FIG. 2;
[0018] FIG. 6 is a cross-sectional view taken along lines 6-6 in
FIG. 2;
[0019] FIG. 7 is a cross-sectional view taken along lines 7-7 in
FIG. 2; and
[0020] FIG. 8 is a cross-sectional view taken along lines 8-8 in
FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0021] Referring now to the drawings, wherein like reference
numerals designate corresponding structure throughout the views,
and referring in particular to FIG. 1, a plastic container 10 that
is constructed according to a preferred embodiment of the invention
is preferably fabricated according to the conventional reheat
stretch blow molding process from a material such as polyethylene
terephthalate, which is commonly known by the acronym PET.
[0022] Plastic container 10 preferably includes a bottom portion
12, a main body portion 14 and an upper portion including a tapered
dome or bell 16 and a threaded finish portion 18. The entire
container 10 is formed from a thin sidewall 15 that defines an
internal space within the container 10.
[0023] The portion of the sidewall 15 that forms the main body
portion 14 is shaped to define a first substantially rigid sidewall
portion 20 that is reinforced with a plurality of substantially
horizontally oriented inwardly extending grooves 22. Main body
portion 14 also includes a second substantially rigid sidewall
portion 24 that is reinforced with a plurality of substantially
horizontally oriented inwardly extending grooves 26. First and
second flexible panel portions 28, 40 are interposed between the
first and second rigid sidewall portions 20, 24 around the
circumference of the main body portion 14, as is shown in FIGS.
1-3.
[0024] The first and second flexible panel portions 28, 40 are
preferably of identical size and shape, so further description that
is made of the first flexible panel portion 28 applies equally to
the second flexible panel portion 40. The flexible panel 28 is
preferably elongated about a central longitudinal axis 30, as is
best shown in FIG. 1, and includes a central portion 32 including a
longitudinal center point 34, an upper portion 36 and a lower
portion 38. The central portion 32 of the flexible panel 28
preferably has a width that is greater than a respective width of
at least one of the upper and lower portions 36, 38. In the
preferred embodiment, the central portion 32 has a width that is
greater than the respective widths of both of the upper and lower
portions 36, 38.
[0025] In the preferred embodiment, flexible panel 28 is
substantially oval in shape as viewed in side elevation, as is best
shown in FIG. 1. Flexible panel 28 is also preferably is convexly
curved in transverse cross-section, as is best shown in FIGS. 4-8.
In addition, as is best shown in FIG. 3, flexible panel 28 is
shaped so as to be substantially flat, with no projections or
raised portions, as viewed in a longitudinal cross-section taken
along the central longitudinal axis 30.
[0026] Preferably, the central portion 32 of the flexible panel 28
has a transverse radius of curvature that is greater than a
transverse radius of curvature of at least one of the upper portion
36 and the lower portion 38.
[0027] FIG. 4 is a cross-sectional view taken at an extreme upper
end of the flexible panel 28, at which the flexible panel 28 has a
first transverse radius of curvature R.sub.1. The flexible panel 28
preferably has a first width W.sub.1 at this location that is a
minimum width for the entire flexible panel 28. A ratio of first
width W.sub.1 to the first transverse radius of curvature R.sub.1
is preferably within a range of about 0.2 to about 1.0, and more
preferably within a range of about 0.4 to about 0.8. Most
preferably, the ratio of first width W.sub.1 to the first
transverse radius of curvature R.sub.1 is within a range of about
0.55 to about 0.74.
[0028] FIG. 5 is a cross-sectional view taken within the upper
portion 36 of the flexible panel 28, at which the flexible panel 28
has a second transverse radius of curvature R.sub.2 that is
preferably greater than the first transverse radius of curvature
R1. The flexible panel 28 preferably has a second width W.sub.2 at
this location that is preferably greater than the first width
W.sub.1. A ratio of second width W.sub.2 to the second transverse
radius of curvature R.sub.2 is preferably within a range of about
0.2 to about 1.0, and more preferably within a range of about 0.4
to about 0.8. Most preferably, the ratio of second width W.sub.2 to
the second transverse radius of curvature R.sub.2 is within a range
of about 0.55 to about 0.74.
[0029] FIG. 6 is a cross-sectional view taken through the
longitudinal center point 34 of the central portion 32 of the
flexible panel 28, at which the flexible panel 28 has a third
transverse radius of curvature R.sub.3 that is preferably greater
than either of the first and second radii of curvature R.sub.1,
R.sub.2. The third transverse radius of curvature R.sub.3 is
preferably a maximum transverse radius of curvature within the
flexible panel 28. The flexible panel 28 preferably has a third
width W.sub.3 at this location that is preferably a maximum width
for the entire flexible panel 28. A ratio of third width W.sub.3 to
the third transverse radius of curvature R.sub.3 is preferably
within a range of about 0.2 to about 1.0, and more preferably
within a range of about 0.4 to about 0.8. Most preferably, the
ratio of third width W.sub.3 to the third transverse radius of
curvature R.sub.3 is within a range of about 0.55 to about
0.74.
[0030] FIG. 7 is a cross-sectional view taken through the lower
portion 38 of the flexible panel 28, at which the flexible panel 28
has a fourth transverse radius of curvature R.sub.4 that is
preferably less than the third transverse radius of curvature
R.sub.3. A flexible panel 28 preferably has a fourth width W.sub.4
at this location that is less than the third width W.sub.3. A ratio
of fourth width W.sub.4 to the fourth transverse radius of
curvature R.sub.4 is preferably within a range of about 0.2 to
about 1.0, and more preferably within a range of about 0.4 to about
0.8. Most preferably, the ratio of fourth width W.sub.4 to the
fourth transverse radius of curvature R.sub.4 is within a range of
about 0.55 to about 0.65.
[0031] Preferably, the respective ratios of the width of the
flexible panel 28 to the transverse radius of curvature for the
locations that are shown in FIGS. 4-7 are substantially equal.
[0032] FIG. 8 is a cross-sectional view taken through an extreme
bottom end of the flexible panel 28, at which the flexible panel 28
has a fifth transverse radius of curvature R.sub.5 that is
preferably less than either the third or fourth radii of curvature
R.sub.3, R.sub.4. The flexible panel 28 preferably has a fifth
width W.sub.5 at this location that is less than the third and
fourth widths W.sub.3, W.sub.4 and that is preferably equal to a
minimum width for the entire panel 28. A ratio of fifth width
W.sub.5 to the fifth transverse radius of curvature R.sub.5 is
preferably within a range of about 0.1 to about 1.0, and more
preferably within a range of about 0.15 to about 0.8. Most
preferably, the ratio of fifth width W.sub.5 to the fifth
transverse radius of curvature R.sub.5 is within a range of about
0.25 to about 0.45.
[0033] In operation, the central portion 32 of the flexible panel
28 deflects to a greater extent while absorbing vacuum uptake than
do the upper and lower portions 36, 38. Because the central portion
32 represents the maximum width of the flexible panel 28, the
efficiency of vacuum uptake is maximized with respect to
conventional vacuum panels that are substantially flat in
longitudinal cross-section.
[0034] The flexible panel 28 is constructed so that the convexity
of the central portion 32 and the upper and lower portions 36, 38
is reduced when accommodating vacuum uptake. Flexible panel 28 may
be constructed so that it inverts during vacuum uptake from the
unstressed convex curvature described above to a concave curvature,
or it may be constructed so that it remains convex, with the degree
of convexity reduced when there is volumetric shrinkage within the
container 10.
[0035] It is to be understood, however, that even though numerous
characteristics and advantages of the present invention have been
set forth in the foregoing description, together with details of
the structure and function of the invention, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
* * * * *