Patent Grant
8109398
1. Field of the Invention
This invention relates generally to the field of plastic containers, and more particularly to plastic containers that are designed to accommodate the volumetric expansion and contraction that is inherent to the hot-fill packaging process.
2. Description of the Related Technology
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).
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.
Hot fill containers are designed to be used with the conventional hot fill process in which a liquid product such as fruit juice 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.
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. In some instances, an island may be defined in the middle of the vacuum panel in order to provide support for an adhesive label that may be placed over the container. In other instances, ribs may be molded into the vacuum panel area in order to provide an enhanced grip surface or to enhance the strength of the vacuum panel area. Grippability for the consumer is an important consideration in the design of many containers. In containers that have vacuum panels with gripping structure, the technology for optimizing the efficacy of the gripping structure and the dimensional stability of the container while it is being gripped while at the same time permitting sufficient flexibility to accommodate volumetric changes within the container is still evolving. Minor changes in curvature and geometry may be important to such optimization. Top load strength and efficient utilization of plastic material are also important design considerations for such containers.
Vacuum panels of conventional hot-fill containers, including those vacuum panels that are provided with structure to enhance gripping, typically are designed to be substantially symmetrical about a central vertical axis as viewed in side elevation. PCT Publication WO 2007/041422 discloses such a container having four vacuum panels. In hot-fill container designs that have an even number of vacuum panels, opposing panels are also typically shaped to be substantially symmetrical about the center axis of the container.
A need has existed for an improved hot fill container design that possesses optimal capacity to accommodate volumetric expansion and contraction, grippability and dimensional stability while being gripped.
Accordingly, it is an object of the invention to provide an improved hot fill container design that possesses optimal capacity to accommodate volumetric expansion and contraction, grippability and dimensional stability while being gripped.
In order to achieve the above and other objects of the invention, a plastic container according to a first aspect of the invention includes a bottom portion and a sidewall portion. The sidewall portion has a maximum outer diameter, and further includes a first pair of opposing first vacuum panels, the first vacuum panels each having a first substantially constant radius of curvature as measured in a horizontal plane, the first substantially constant radius of curvature being substantially constant from an upper end of each of the respective first vacuum panels to a lower end, and wherein a ratio of the first substantially constant radius of curvature to the maximum outer diameter is within a range of about 0.3 to about 2.5; and a second pair of opposing second vacuum panels, at least one of the second vacuum panels including gripping structure, the second vacuum panels each having a second substantially constant radius of curvature as measured in a horizontal plane, the second substantially constant radius of curvature being substantially constant, excluding the gripping structure, from an upper end of each of the respective second vacuum panels to a lower end, and wherein a ratio of the second substantially constant radius of curvature to the maximum outer diameter is within a range of about 0.2 to about 2.
According to a second aspect of the invention, a plastic container includes a bottom portion; and a sidewall portion, the sidewall portion having a maximum outer diameter, and wherein the sidewall portion further includes a first pair of opposing first vacuum panels; and a second pair of opposing second vacuum panels, at least one of the second vacuum panels including gripping structure and being shaped so as to be asymmetric about a central vertical axis when viewed in side elevation.
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.
Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to
Container 10 is adapted for use in hot-fill applications, but could potentially be used for other applications, and in particular those applications for which significant changes in internal container volume as a result of pressure and temperature differences are anticipated.
Sidewall portion 14 is preferably generally cylindrical and has a maximum outer diameter, DMAX, as is shown in
The first vacuum panels 16, 18 each preferably are shaped so as to define a first substantially constant radius of curvature R1, as measured in a horizontal plane, that is substantially constant from an upper end 24, 28 of each of the respective first vacuum panels 16, 18 to a lower end 26, 30 of the respective vacuum panels 16, 18.
Preferably, a ratio of the first substantially constant radius of curvature R1 to the maximum outer diameter DMAX is within a range of about 0.3 to about 2.5. More preferably, the ratio of the first substantially constant radius of curvature R1 to the maximum outer diameter DMAX is within a range of about 0.4 to about 1.5. Most preferably, the ratio of the first substantially constant radius of curvature R1 to the maximum outer diameter DMAX is within a range of about 0.6 to about 0.9.
Sidewall portion 14 also preferably defines a second pair of opposing second vacuum gripping panels 20, 22. As will be discussed in greater detail below, at least one of the second, gripping vacuum panels 20, 22 preferably includes gripping structure for facilitating secure gripping of the container 10 by a consumer. In the preferred embodiment, vacuum panel 20 is provided with a plurality of generally horizontally oriented concave grooves 42, 44, 46, 48 and 50. Additionally, vacuum panel 22 is preferably provided with a plurality of generally horizontally oriented protruding ribs 52, 54, 56, 58 and 60 that are shaped and spaced so as to fit between the fingers of a typical consumer.
The second vacuum panels 20, 22 are each shaped in areas not including the ribs 52, 54, 56, 58 so as to define a second substantially constant radius of curvature R2 as measured in a horizontal plane. The second substantially constant radius of curvature R2 is substantially constant, excluding the above-described gripping structure, from an upper end 32, 36 of each of the respective second vacuum panels 20, 22 to a lower end 34, 38 of the vacuum panels 20, 22.
Preferably, a ratio of the second substantially constant radius of curvature R2 to the maximum outer diameter DMAX is within a range of about 0.2 to about 2. More preferably, the ratio of the second substantially constant radius of curvature R2 to the maximum outer diameter DMAX is within a range of about 0.3 to about 1.5. Most preferably, the ratio of the second substantially constant radius of curvature R2 to the maximum outer diameter DMAX is within a range of about 0.5 to about 0.7.
In addition, the vacuum panels 16, 18, 20 and 22 are preferably shaped so that a ratio of the first substantially constant radius of curvature R1 to the second substantially constant radius of curvature R2 is within a range of about 0.15 to about 12.5. More preferably, the ratio of the first substantially constant radius of curvature R1 to the second substantially constant radius of curvature R2 is within a range of about 0.25 to about 5. Most preferably, the ratio of the first substantially constant radius of curvature R1 to the second substantially constant radius of curvature R2 is within a range of about 0.85 to about 1.8.
According to another aspect of the invention, at least one of the second, gripping pair of vacuum panels 20, 22 may be shaped so as to be asymmetric about a central vertical axis 62 when viewed in side elevation, as is shown in
In the preferred embodiment, both of the vacuum panels 20, 22 are wider at their upper ends than at their lower ends. Referring to
As was briefly described above, vacuum panel 20 is provided with a plurality of generally horizontally oriented concave grooves 42, 44, 46, 48 and 50. Additionally, vacuum panel 22 is preferably provided with a plurality of generally horizontally oriented protruding ribs 52, 54, 56, 58 and 60 that are shaped and spaced so as to fit between the fingers of a typical consumer. As
In addition, the protruding ribs 52, 54, 56, 58 and 60 are sized and spaced so that respective smooth spaces are defined therebetween for comfortably receiving the fingers of the typical consumer. A minimum vertical space LF is therefore defined between adjacent ribs, which is preferably at least 0.5 inch, but is more preferably at least 0.55 inch.
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.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5971184 | Krishnakumar et al. | Oct 1999 | A |
| 6494333 | Sasaki et al. | Dec 2002 | B2 |
| 6837390 | Lane et al. | Jan 2005 | B2 |
| 6935525 | Trude | Aug 2005 | B2 |
| 7014056 | Trude | Mar 2006 | B2 |
| 7073675 | Trude | Jul 2006 | B2 |
| 7118002 | Saito et al. | Oct 2006 | B2 |
| D542666 | Trude | May 2007 | S |
| 7458478 | Kamineni | Dec 2008 | B2 |
| 20010035392 | Ota et al. | Nov 2001 | A1 |
| 20030205550 | Prevot et al. | Nov 2003 | A1 |
| 20050139572 | Pedmo et al. | Jun 2005 | A1 |
| 20050218107 | Sabold et al. | Oct 2005 | A1 |
| 20060076310 | Mooney et al. | Apr 2006 | A1 |
| 20060157439 | Howell | Jul 2006 | A1 |
| 20060180568 | Lane | Aug 2006 | A1 |
| 20070075032 | Kelley et al. | Apr 2007 | A1 |
| 20070090083 | Trude | Apr 2007 | A1 |
| 20070125743 | Pritchett et al. | Jun 2007 | A1 |
| 20070187355 | Kamineni | Aug 2007 | A1 |
| 20070210028 | Heisner et al. | Sep 2007 | A1 |
| 20070257004 | Howell et al. | Nov 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| 2006039523 | Apr 2006 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20100301003 A1 | Dec 2010 | US |
