U.S. patent application number 11/017258 was filed with the patent office on 2006-06-22 for plastic container with champagne style base.
This patent application is currently assigned to Ball Corporation. Invention is credited to Peter J. Crandall, Erik E. Gatewood.
Application Number | 20060131257 11/017258 |
Document ID | / |
Family ID | 36594372 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060131257 |
Kind Code |
A1 |
Gatewood; Erik E. ; et
al. |
June 22, 2006 |
Plastic container with champagne style base
Abstract
A champagne type base for a molded polymeric container has an
annular step immediately inside an annular contact ring. A push-up
area is a central portion of the base immediately surrounding the
container longitudinal axis. A transition region between the
push-up area and the annular step provides for outstanding base
stabilization. The transition region includes an upwardly arching
surface extending between the annular step and the push-up area
with a plurality of integrally molded, spaced apart, radially
extending and downwardly projecting hollow ribs. Each of the ribs
has a lower curved surface extending substantially continuously
from the push-up area to the inner margin of the annular step.
Inventors: |
Gatewood; Erik E.;
(Lafayette, CO) ; Crandall; Peter J.; (Hastings,
NY) |
Correspondence
Address: |
INDIANAPOLIS OFFICE 27879;BRINKS HOFER GILSON & LIONE
ONE INDIANA SQUARE, SUITE 1600
INDIANAPOLIS
IN
46204-2033
US
|
Assignee: |
Ball Corporation
|
Family ID: |
36594372 |
Appl. No.: |
11/017258 |
Filed: |
December 20, 2004 |
Current U.S.
Class: |
215/373 ;
220/606 |
Current CPC
Class: |
B65D 2501/0036 20130101;
B65D 1/0276 20130101; B65D 79/005 20130101 |
Class at
Publication: |
215/373 ;
220/606 |
International
Class: |
B65D 90/02 20060101
B65D090/02; B65D 6/28 20060101 B65D006/28 |
Claims
1. A molded polymeric container, including a body portion having a
longitudinal axis, a sidewall and a champagne type base portion
that is molded integrally with said sidewall, said champagne type
base portion comprising: a lower end that defines an annular
contact ring for supporting the container with respect to an
underlying surface; an annular step situated immediately radially
inward of the annular contact ring, the annular step having a
substantially vertical outer wall and a substantially horizontal
inner wall, the inner wall having an inner margin; a push-up area
immediately surrounding the longitudinal axis; and a transition
region interposed between the push-up area and the annular step,
the transition region including an upwardly arching surface
extending between the push-up area and the annular step, and a
plurality of integrally molded, spaced apart, radially extending,
and downwardly projecting ribs, each rib having a lower curved
surface extending substantially continuously from the push-up area
to the annular step.
2. The molded polymeric container of claim 1 wherein the upwardly
arching surface has a radius of curvature R.sub.S, the rib lower
curved surface has a radius of curvature R.sub.R, and
R.sub.S>R.sub.R.
3. The molded polymeric container of claim 2 wherein: 2.0
R.sub.R>R.sub.S>1.5 R.sub.R.
4. The molded polymeric container of claim 3 wherein R.sub.S 1.7
R.sub.R.
5. The molded polymeric container of any of claims 1, 2, 3 or 4
wherein the maximum height to base width ratio of each rib is less
than 1.
6. The molded polymeric container of claim 5 wherein the maximum
height to base width ratio of each rib is about 0.7.
7. The molded polymeric container of claim 5 wherein each rib
includes two sides leading from the lower curved surface to the
adjacent upwardly arching surface, the two sides of each rib
diverging from each other.
8. The molded polymeric container of claim 7 wherein the angle of
divergence of the two sides of each rib from each other is between
about 25.degree. and 35.degree..
9. The molded polymeric container of claim 5 wherein the annular
contact ring is horizontally planar and has a width of about 0.15
R.
10. The molded polymeric container of claim 5 further comprising a
convex heel portion joining an outer margin of the annular contact
ring, the heel portion having a vertical radius of curvature of
about 0.5 R.
11. A molded polymeric container, including a body portion having a
longitudinal axis, a sidewall and a champagne type base portion
that is molded integrally with said sidewall, said champagne type
base portion comprising: a lower end that defines a horizontally
planar annular contact ring for supporting the container with
respect to an underlying surface; an annular step situated
immediately radially inward of the annular contact ring, the
annular step having a substantially vertical outer wall and a
substantially horizontal inner wall, the inner wall having an inner
margin; a push-up area immediately surrounding the longitudinal
axis; and a transition region interposed between the push-up area
and the annular step, the transition region being substantially
devoid of any extreme angles and tapers, the transition region
including an upwardly arching surface extending between the push-up
area and the annular step, and a plurality of integrally molded,
spaced apart, radially extending, and downwardly projecting ribs,
each rib having a lower curved surface extending substantially
continuously from the push-up area to the annular step.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention is directed to molded plastic bottles
having a champagne style bottom structure closing the container
lower end. The phrase champagne style is used in reference to a
base having an outside surface rotationally symmetric about a
longitudinal axis of the bottle including a convex heel having an
upper margin integrally formed with the lower end portion of the
bottle sidewall, and a central concavity separated from the convex
heel by a continuous standing ring that supports the bottle on any
underlying planar surface.
[0003] The present invention particularly relates to blow-molded
containers of biaxially oriented thermoplastic materials such as
polyethylene terephthalate that are designed to be filled with a
hot liquid or semi-liquid product and hermetically sealed,
generally referred to as thin-walled, hot-fill containers. The
invention pertains to improvements in the design of such containers
intended to achieve a container base that, despite the low weight
of polymer used to form the container, resists the hydraulic and
thermal shock of the entering hot product during a filing
operation, yet when cooled, retains the desired container
configuration despite the development of a partial vacuum within
the container.
[0004] 2. General Background
[0005] It is well recognized that the exposure of any plastic
container to elevated temperatures tends to soften the plastic
material and make the container less resistant to deformation.
Thin-walled, hot-fill containers are typically used for packaging
beverages and other food products that must be placed in the
container while hot, the container being quickly capped to preserve
the quality of the contents. During the filling process, the
container is subjected to temperatures from the hot product on the
order of about 85.degree. C. The interior of the container base is
also subjected to a hydraulic force from the fast flowing hot
product as it enters the container. The combination of the thermal
and hydraulic forces can easily cause deformation of the container
base, which if insufficiently controlled can lead to failure during
the immediately subsequent capping operation.
[0006] The desire for stability of base configuration is not
limited to hot-filled containers. Plastic containers used for
beverages and other food products that are subjected to a
post-capping pasteurization process are also subjected to
considerable internal pressures that can lead to base deformation.
During a typical pasteurization process, the contents of the
container are heated, to a temperature that is within the general
range of about 62.degree. to 67.degree. C. As the temperature rises
during the pasteurization process, the internal pressure also
rises, sometimes to a level of about 2 to 21/2 times higher than
what occurs during the packaging of non pasteurized beverages.
Under these circumstances, the base of the molded plastic container
is vulnerable to outward deformation due to the internal pressures,
which can affect the continued serviceability of the container.
[0007] Dimensional stability in the base region of molded plastic
containers is most important, and particularly in the portions of
the base region that are designed to support the container with
respect to any underlying surface. In the case of a champagne type
base, the dimensional stability of the areas adjacent to the
annular support ring is particularly important. Thus, there is a
continuing need for an improved molded plastic container having a
base that exhibits outstanding dimensional stability under
conditions of relatively high pressure and/or temperature and, in
particular, that is designed to be particularly resistant to
deformation in areas of the base that are designed to support the
container with respect to any underlying surface.
BRIEF SUMMARY
[0008] A molded polymeric container of the present invention
satisfies such needs by providing a champagne type base having an
annular contact ring for supporting the container with respect to
an underlying surface. An annular step is situated immediately
radially inward of the annular contact ring, the annular step
having a substantially vertical outer wall and a substantially
horizontal inner wall. A push-up area is provided at a central
portion of the base that is immediately adjacent to and surrounds
the longitudinal axis of the container. A transition region is
interposed between the push-up area and the annular step that
provides for outstanding base stabilization. The transition region
includes an upwardly arching surface extending between the annular
step and the push-up area with a plurality of integrally molded,
spaced apart, radially extending and downwardly projecting hollow
ribs. Each of the ribs has a lower curved surface extending
substantially continuously from the push-up area to the inner
margin of the annular step.
[0009] The upwardly arching surface of the container base of the
present invention can have a radius of curvature R.sub.S that is
greater than the radius of curvature of the rib lower surface
R.sub.R. The radius of curvature R.sub.S can be between about 1.5
R.sub.R and 2.0 R.sub.R, and in a preferred embodiment the radius
of curvature R.sub.S can be about 1.7 R.sub.R. The ratio of the
height to base width of each rib can be less than 1.0 down to at
least about 0.7. Each of the ribs can have two sides diverging from
the lower curved surface to an adjacent portion of the upwardly
arching surface. The angle of divergence of the two sides can be
between about 25.degree. and about 35.degree.. The contact ring can
be defined by a horizontal planar annulus that can be several times
the width of the horizontal inner wall of the annular step. The
push-up area of the base can include a horizontal planar ring with
a central depending nib aligned with the longitudinal axis of the
container.
[0010] The champagne type base of the present invention exhibits
exceptionally stable geometry from manufacture through typical
hot-fill conditions and subsequent storage despite the use of a
modest amount of polymer. This base can be combined with a variety
of side wall structures to provide a remarkably satisfactory
container for hot-fill operations. The scope of the containers that
can be constructed with a champagne type base of the present
invention will become more apparent from the following description
and accompanying drawings detailing an illustrative example of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a side elevation view of a molded polymeric
container that can incorporate a champagne type base of the present
invention.
[0012] FIG. 2 is a bottom plan view of the container shown in FIG.
1.
[0013] FIG. 3 is another bottom plan view of the same
container.
[0014] FIG. 4 is a sectional view taken along line A-A of FIG.
2.
[0015] FIG. 5 is a sectional view taken along line B-B of FIG.
3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] A container 10 of the present invention is shown in FIG. 1
to be generally symmetric about a vertical axis Y, and has an open
mouth 12 surrounded by a lip 14 intended to cooperate with a cap,
not shown, to seal the container and contents. A cap-engaging
finish 16 is located below the lip 14, which is illustrated to have
the form of a spiral thread 18. The particular form of the finish
16 can be varied to include a range of thread styles or even be
replaced with any number of non-threaded finishes designed to
accept a crown type or other cap. A pilfer ring 20 can be located
immediately below the finish 16 to engage a pilfer-indicating band
of a cap. A support ring 22 can be provided below the pilfer ring
20 that facilitates handling of the container 10 as well as the
handling of the parison or preform from which the container 10 is
formed. A neck portion 24 is located immediately below the support
ring.
[0017] A shoulder portion 26 extends outward and downward from a
lower margin of the neck portion 24. The shoulder portion 26 can
include an indented hoop ring 28 to provide added strength to the
container 10. A bumper ring 30 can be provided at a lower margin of
the shoulder portion 26 that can define the maximum radius R of the
container sidewall 32 measured from the axis Y. A lower margin of
the bumper ring 30 can also define the upper margin 34 of a label
receiving portion 36 that is intended to receive a separate label,
not shown. The label can be a sheet of plastic, paper, or other
similar material of suitable dimension that can surround the entire
sidewall 32 of the container 10. The label typically covers the
container 10 from the upper margin 34 down to the lower margin 38
of the label receiving portion 36. The label receiving portion 36
can also include one or more reinforcing hoop rings 40. A plurality
of vacuum compensation panels 42 can also be provided within the
label receiving portion 36 of the sidewall 32. A convex heel
portion 44 extends downward from the container sidewall 32 to an
annular contact ring 46 that supports the container 10 with respect
to any underlying surface.
[0018] The convex heel portion 44 and annular contact ring 46 form
the outer margin of the base 48 of container 10 shown in FIGS. 2 to
5. When viewed in a vertical section as shown in FIG. 4, the convex
heel portion 44 is arcuate, generally having a vertical radius of
curvature R.sub.H that is less than R. The vertical radius of
curvature R.sub.H of the convex heel portion 44 can be about 0.5 R.
The annular contact ring 46 can have a generally planar bottom
surface 50 that extends from a point of merger 52 with the convex
heel portion 44 inward to a small annular step 54. The distance
between the point of merger 52 and the annular step 54 can be about
0.15 R. The annular step 54 is formed by a substantially vertical,
inwardly facing, outer wall 56 that extends upward to a
substantially horizontal band 58. The band 58 extends inwardly from
the vertical outer wall 56 to an inner margin 60 of the annular
step 54.
[0019] A transition region 62 extends radially inward from the
inner margin 60 of the annular step 54. The transition region 62
includes a plurality of upwardly arching segments 64 that are
spaced from each other by a plurality of ribs 66. When viewed in a
vertical section as shown in FIG. 4, the upwardly arching segments
64 can be defined by a single radius of curvature R.sub.S extending
substantially continuously from the annular step inner margin 60 to
a margin 72 that defines the outer perimeter of a central push-up
area 74. The radius of curvature R.sub.S of the upwardly arching
segments 64 can be about 0.5 R. Each of the ribs 66 has two sides
68 diverging from adjacent portions of the upwardly arching
segments 64 to merge with a lower curved surface 70 of the rib 66.
The sides 68 of the ribs 66 diverge from each other at an angle
.theta. that can be between about 25.degree. and 35.degree. as
shown in FIG. 5. Due to the differences in curvature of the
surfaces 64 and 70 the ribs achieve a maximum height H about half
way between the annular step inner margin 60 and the central
push-up area margin 72 as shown in FIG. 4. As seen in FIG. 5, each
rib 66 has a base width W at the point of maximum height H, ratio
of H/W being less than 1 and can be about 0.7. When viewed in a
vertical section, as shown in FIG. 4, the lower curved surface 70
of the ribs 66 is defined by a radius of curvature R.sub.R
extending over a major portion of the rib lower surface 70. The
radius of curvature R.sub.S of the upwardly arching segments 64 is
generally greater than the radius of curvature R.sub.R of the rib
lower surfaces 70. The radius of curvature R.sub.S can be between
about 1.5 and 2.0 times the radius of curvature R.sub.R. The radius
of curvature R.sub.S is preferably about 1.7 times the radius of
curvature R.sub.R.
[0020] Both the upwardly arching segments 64 and ribs 66 converge
to an inner margin 72 that defines the outer perimeter of a central
push-up area 74 immediately surrounding the longitudinal axis Y of
the container 10. The central push-up area 74 is generally
horizontally planar, but can contain a spru artifact 76. The
central push-up area is maintained in position relative to the
annular contact ring 46 by virtue of the stress created in the
sides 68 of the ribs 66 in the event of any downward displacement
of the central push-up area 74. As a result, the champagne type
base 48 exhibits exceptionally stable geometry from manufacture
through typical hot-fill conditions.
[0021] During the blow-molding of a container to have a base of the
present invention, the plastic forming the base 48 more intimately
contacts the mold interior and is thus subjected to better heat
transfer from the plastic forming the base to the cooled mold. This
more intimate contact is established because of the previously
described special geometric relationships in the base 48 which
reduce or eliminate any extreme angles and tapers that commonly are
present in similar contemporary base designs. As a result, the
plastic forming the base 48 of the present invention cools more
completely during a molding cycle of a given length of time. The
more thorough cooling results in less post molding creep of the
base structure. The more thorough cooling may be used to increase
the bottle production rate. The base 48 can be combined with a
variety of side walls 32 to provide a remarkably satisfactory
container for hot-fill operations.
[0022] The foregoing detailed description of the embodiment shown
in the Figures should be regarded as merely illustrative rather
than limiting, and the following claims, including all equivalents,
are intended to define the spirit and scope of this invention.
* * * * *