AU2011203263B2 - System and method for handling a container with a vacuum panel in the container body - Google Patents

Abstract

Provided herein are systems and methods for handling filled containers, the system comprising: filling means for filling the containers with a product, the product being at an elevated temperature; sealing means for sealing the filled containers using a cap; vacuum creating means for creating a vacuum in each of the filled and sealed containers by cooling; conveying means for conveying the containers having vacuums created therein with a wall portion and a section in a first position, the containers being conveyed such that their bearing surfaces stand on a flat surface, wherein, in the first position, no portion of the wall portion and the section extend below the bearing surface of a base portion of the container; and repositioning means for repositioning the wall portion and the section of each container from the first position to a second position partially to reduce the vacuum, the repositioning being done after the containers are conveyed by said conveying means, wherein at least one vacuum panel reduces a portion of the vacuum not reduced by the repositioning. WO 2007/047574 PCT/US2006/040361

Description

AUSTRALIA Regulation 3.2 Patents Act 1990 Complete Specification Standard Patent DIVISIONAL APPLICANT: Graham Packaging Company, L.P. Invention Title: SYSTEM AND METHOD FOR HANDLING A CONTAINER WITH A VACUUM PANEL IN THE CONTAINER BODY The following statement is a full description of this invention, including the best method of performing it known to me: P \COmmnWord97\34001-34SO0\34295GRA\2011D)704 APO - Fie Patent Application.doc SYSTEM AND METHOD FOR HANDLING A CONTAINER WITH A VACUUM PANEL IN THE CONTAINER BODY BACKGROUND OF THE INVENTION Field of the Invention [0001 The present invention generally relates to a structure of a container base, and more particularly to a base of a container that is repositionable about a hinge in order to partially 5 reduce vacuum pressure experienced by a container during a hot-fill process. Related Art [0002] Conventionally, manufacturers use a hot-fill process to add a product to a container at an elevated temperature, about 82"C, which can be near the glass transition temperature of the plastic material in the plastic container, and then cap the container. As the 10 container and its contents cool, the contents tend to contract and this volumetric change creates a partial vacuum within the container. In the absence of some means for accommodating these internal volumetric and barometric changes, containers tend to deform and/or collapse. For example, a round container can undergo ovalization, or tend to distort and become out of round. Containers of other shapes can become similarly distorted. In addition to these changes that I 5 adversely affect the appearance of the container, distortion or deformation can cause the container to lean or become unstable when placed upon a flat surface. 100031 To overcome the partial vacuum within the container created by the hot fill process, manufacturers have resorted to various different methods to preserve the integrity of the container. In one known method, vertically oriented vacuum panels are formed on the sidewalls 20 of the container. The vacuum panels are adapted to flex inward in response to an internal vacuum to reduce the volume within the container, which lowers the internal vacuum pressure. However, to significantly reduce the vacuum pressure caused by the hot-fill process, these types of vacuum panels are required over a significant portion of the container and are considered by some to be visually unappealing. 100041 Another known method to compensate for internal vacuum pressure is by forming patterned structures on the container. A region of the container having patterned structure of multiple shapes, curves, and bends increases rigidity of the plastic at the region. However, adding these types of patterned structure is required over a significant portion of the container in order to preserve the structural integrity of the container caused by the volumetric 1 WO 2007/047574 PCT/US2006/040361 changes in the hot-fill process. Patterned structures also add to the amount of plastic within the container, which adds to the weight, and ultimately to the cost. 100051 What is needed is an improved container that overcomes shortcomings of conventional solutions. 5 BRIEF SUMMARY OF THE INVENTION [00061 This invention differs from the prior art in modifications which were not previously known or suggested. [00071 The present invention claims a base of a container, a container, and a method of compensating for vacuum pressure changes within a container. 10 [00081 A base of a container includes a bearing surface, a hinge, a first wall sloping in a first direction from the bearing surface to the hinge, and a second wall sloping in a second direction away from the hinge, wherein the second wall is adapted to be repositioned about the hinge with substantially no movement of the first wall. [0009] A container including an upper portion having an opening into the container, 15 a container body positioned below the tipper portion and defining an interior of the container, and a base adjoining the container body at an end of the container opposite from the upper portion. The base includes a hinge, a first wall between the container body and the hinge, the first wall sloping toward the interior of the container, and a second wall adjoining the hinge, the second wall sloping away from the interior of the container and being adapted to be repositioned 20 about the hinge. [000101 A method of compensating for vacuum pressure changes within a container including hot filling the container with a product, sealing the container with a closure, cooling the hot filled container, repositioning a base wall adjoining a hinge of the base about the hinge from an outward extending position to an inward extending position, thereby reducing the 25 internal pressure of the container, wherein prior to repositioning, the container is adapted to stand upright on a flat surface. 1000111 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. 30 BRIEF DESCRIPTION OF THE DRAWINGS 2 WO 2107/047574 PCT/JS2006/040361 100012] 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. 5 [000131 FIGs. 1A- 1C depict an exemplary embodiment of a container having a base structure according to the present invention; [000141 FIG. 2 illustrates a cross sectional view of an exemplary embodiment of a container according to the present invention. [000151 FIGs. 3A-3G illustrate alternative exemplary embodiments For the structure of 10 a base of a container according to the present invention. DETAILED DESCRIPTION OF THE INVENTION {000161 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 15 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 parting from the spirit and scope of the invention. [000171 The present invention generally relates to a base structure of a container that can be repositioned about a hinge to partially reduce an internal vacuum pressure within the 20 container caused by cooling of a product after a hot fill process. FIGs. I A-tC illustrate an exemplary embodiment of a container 100 having a base structure according to the present invention. Initially, the invention will be described referring to FIGs. IA-IC. 100018J According to an embodiment of the present invention, the container 100 includes an upper portion 102, a shoulder 104, a container body 106, and a base 108. The tipper 25 portion 102 of the container 100 generally is any structure having an opening into the interior of the container 100 and is adapted to receive a closure (not shown), The closure is any device used to create a substantially air tight seal for the hot-filled product within the container 100, thus substantially preventing air from entering the container 100 through the upper portion 102. In one embodiment, the upper portion 102 includes threads 112 that are adapted to couple with a 30 closure that is a twist-on cap. The cap may be twisted onto the threads 112 of the upper portion 102 to create a seal with the container 100. In an alternative embodiment, a sealing plug may be 3 WO 2007/047574 PCT/US2006/040361 placed in the upper portion 102 to seal the container 100. Other closures or seals may be used, as will be appreciated by those of skill in the art. 1000191 The shoulder 104 of the container 100 extends from the top of the container body 106 to the bottom of the upper portion 102. Generally, the shoulder 104 narrows as it 5 progresses from the container body 106 to the bottom of the upper portion 102. The shoulder 104 may have any desired shape, or may be omitted from the container 100. The shoulder 104 may include patterns, shapes, and other known geometries, or alternatively, may be substantially smooth. In the depicted embodiment, the width of the bottom of the shoulder 104 corresponds to the width of the top of the container body 106, and narrows by curving inward as the shoulder 10 104 approaches the upper portion 102. The shoulder 104 curves outward before reaching the upper portion 102, and then curves inward as the shoulder 104 reaches the upper portion 102. The shoulder 104 may be other shapes and include other patterns, as will be appreciated by those of skill in the art. [000201 The container body 106 of the container 100 extends from the base 108 to the 15 shoulder 104 and defines an interior of the container 100. The container body 106 is positioned below the upper portion 102. In an alternative embodiment, if the shoulder 104 is omitted from the container 100, the container body 106 extends to the upper portion 102. The container body 106 may be any known asymmetrical or symmetrical shape, such as, for example, cylindrical, square, rectangular, or other geometries. Optionally, the container body 106 of the container 100 20 may include patterned support structure or vacuum panels. The patterned support structure and the vacuum panels help provide structural integrity for the container 100, as will be discussed later in detail. [00021] In the depicted embodiment, the container body 106 is cylindrical and has ribs 114 and multiple vacuum panels 116. The ribs 114 may be a series of recessed sections 25 followed by non-recessed sections on the container body 106. The vacuum panels 116 may be substantially flat recessed sections having a much larger recessed area than that of the ribs 114. Alternatively, vacuum panels may be configured to form a grip region. Other vacuum panel designs are known in the art. A container according to the invention may include different types of vacuum panels. The ribs 114 may include other types and shapes and both the ribs 114 and 30 the vacuum panels 116 may be placed at alternate locations on the container body 106, as will be appreciated by those of skill in the art. The ribs 114 and the vacuum panels 116 may also be 4 WO 2007/047574 PCTIUS2006/040361 omitted from the container body 106, and may be placed at other locations on or omitted from the container 100. [000221 As depicted in FIG. 1B, the base 108 includes a bearing surface 118, a first wall 120, a hinge 122, a second wall 124, and a section 126. The bearing surface 118 of the base 5 108 is the contact surface of the container [00 that may contact a flat surface when the base 108 is placed upright on the flat surface. The container 100 is upright on the flat surface when a substantial portion of the bearing surface 118 contacts the flat surface and the flat surface is underneath the container 100. The bearing surface 118 may be formed in other asymmetrical or symmetrical geometries, as will be appreciated by those of skill in the art.. 10 [000231 The first wall 120 of the container 100 is located between the bottom of the container body 106 and the hinge 122. The first wall 120 slopes in a direction from the bearing surface 118 to the hinge 122 towards the interior of the container 100. The slope of the first wall 120 may be curved or linear, or a combination of curved and linear sections. The first wall 120 may include indented ribs 132 to add strength to the base 108, the first wall 120, and the 15 container 100. Typically, when plastic is formed as ribs, as opposed to a flat or smooth surface, the rigidity of the plastic increases in the region around the ribs. Thus, ribs 132 improve the structural integrity of the base 108, and analogously, the ribs 114 strengthen the container body 106 for similar reasons. [000241 In one embodiment, the first wall 120 includes support braces 130 between 20 ribs 132. As depicted, the ribs 132 and the support braces 130 are adjoining. The support braces 130 extend substantially from the bearing surface 118 to the hinge 122. The ribs 132 also extend substantially from the bearing surface 118 to the hinge 122. However, in the depicted embodiment, the ribs 132 follow substantially a straight line between the bearing surface 118 and the hinge 122, whereas the support braces 130 are a two part revolved surface formed on the 25 first wall 120. The support braces 130 are two substantially flat sections that intersect at an angle and extend outward from the straight line between the bearing surface 118 and the hinge 122. 1000251 The hinge 122 of the base 108 is located at the intersection of the first wall 120 and the second wall 124. The hinge 122 is the location about which the second wall 124 is 30 repositioned after the container 100 is hot-filled and sealed, as will be discussed later in detail. The hinge 122 is depicted as a circular ring that is offset from the bearing surface 1 18. However, 5 WO 2007/047574 PCT/US2006/040361 the hinge 122 may be other symmetrical or asymmetrical shapes, as will be appreciated by those of skill in the art [000261 Prior to repositioning, the second wall 124 slopes in a direction away from the hinge 122, which is also away from the interior of the container 100. The second wall t24 5 slopes in the direction of the section 126. The slope of the second wall 124 may be curved or linear, or a combination of curved and linear sections, as will be appreciated by those of skill in the art. In the depicted embodiment, the second wall 124 slopes substantially linearly from the hinge 122 to the section 126. The second wall 124 in the illustrated embodiment also includes creases 128 that facilitate the repositioning of the second wall 124 about the hinge 122. The 10 creases 128 are adapted to flex during repositioning of the second- wall 124. [00027] The section 126 is centrally located within the second wall 124, and may be concave, convex, or flat relative to the interior of the container 100. The section 126 is adapted to receive a mechanical device that repositions the second wall 124 about the hinge 122. The mechanical device may apply a force on the section 126 to reposition the second wall 124. 15 [000281 The structure of the base 108 is adapted to partially reduce an internal vacuum pressure experienced by the container 100 during hot-fill processing. After the container 100 is hot-filled with a product and sealed with a closure, such as, for example, a cap, the product begins to cool within the container 100. Cooling of the product creates an internal vacuum pressure within the container 100 due to a reduction in product volume caused by the cooling 20 and contraction of the product. The internal vacuum pressure within the container 100 tends to cause the container 100 to collapse inwardly. [00029] To overcome a portion of the internal vacuum pressure within the container 100, the second wall 124 may be repositioned about the hinge 122. FIG. I.C illustrates an exemplary embodiment of the second wall 124 after repositioning about the hinge 122. During 25 repositioning, the second wall 124 is moved from a position extending outward from the container 100 to a position extending inward into the interior of the container 100. 100030] Inwardly repositioning the second wall 124 reduces the amount of volume within the interior of the container 100. This reduction in volume partially reduces the internal vacuum pressure within the container 100 caused by the volumetric shrinkage of the cooling 30 product. The amount of volume reduced relates to the volume of the region within the base 108 of the container 100 bounded by the second wall 124 and the section 126. The volume reduced 6 WO 20071047574 PCT/US2006/040361 relates to the difference of internal volume between the container 100 shown in FIG. lB with the second wall 124 extending outward, and the container 100 shown in FIG. I C with the second wall 124 extending inward into the interior of the container 100. 1000311 The volume of the space bounded by the second wall 124 and the section 126 5 may be used to control the amount of volumetric pressure reduction within the container 100. The larger the volume of the space bounded by the second wall 124 and the section 126, the larger the reduction of internal pressure. This may be used to control the amount of ribs 114 on the remainder of the container 100, and also may be used to affect the size of the vacuum panel panels 116 required to meet the needs of customers and hot-filling processors. In particular, by 10 partially accommodating the pressure changes by use of a base according to the invention, the number or size of ribs and/or vacuum panels can be reduced. Persons skilled in the art can thus calculate the amount of the volumetric change achievable by repositioning of the second wall, and adjust the container design accordingly. [000321 Substantially no net movement or change in location of the first wall 120 15 during or after repositioning of the second wall 124 because of the rigidity of the first wall 120. In one embodiment, the strength of the first wall 120 prevents deformation of the base 108 -during inversion. Applying a force to section 126 to invert the second wall 124 creates stress on the plastic material of the container 100. Deformation of the container 100 may cause folding of the bearing surface 118, buckling of the plastic in the base 108, or other deformations in the 20 container 100. To prevent deformations, the structure of the base 108 including the ribs 132 and the support braces 130 provides the first wall 120 with sufficient strength to prevent deformation of the container 100 and the base 108 at, but not limited to, the bearing surface 118. This allows the container 100 and the first wall 120 to withstand the stresses created on the plastic during inversion and allows the container 100 to stably stand upright on a flat surface after inversion. 25 [000331 To compensate for the remainder of the vacuum not compensated for by repositioning the second wall 124, the container 100 also includes the vacuum panels 116 and the ribs 14. In response to internal vacuum pressure, the vacuum panels 116 flex inward to further reduce the volume of the container 100, and the strength of the ribs 114 is able to withstand the remaining vacuum pressure. Thus by using the vacuum panels 116 and the ribs 30 114 in combination with the repositionable second wall 124, the structural integrity of the container 100 is preserved while reducing the vacuum within the container 100. The 7 WO 20071047574 PCT/US2006/040361 repositionable second wall 124 allows for container manufacturers to incorporate fewer vacuum panels and ribs in their containers, while not sacrificing container shape or container integrity due to the internal vacuum pressure stresses caused by the hot-fill process. The repositionable second wall 124 also allows using less plastic material per container, which results in lower per 5 container costs in the container itself, as well as in lower costs in transporting the lighter container. [000341 In contrast with prior art solutions, the container 100 is able to stand stably upright on a flat surface prior to repositioning the second wall 124 without requiring a support mechanism for the container 100. FIG. 2 illustrates an exemplary embodiment of a cross 10 sectional view of the container 100 prior to repositioning of the second wall 124 standing on a planar surface P according to the present invention. To allow the container 100 with a repositionable second wall 124 to stably stand upright on a flat surface, the section 126 and the second wall 124 do not extend outward from the container 100 beyond the bearing surface 118, thus allowing the bearing surface I18 of the container 100 to contact the flat surface. In one 15 embodiment, at least a portion of the section 126 contacts the flat surface. The ability to stand stably on a flat surface is advantageous in that the bearing surface 118 is the area of the container 100 designed to bear the load of the container and of the hot-filledproduct. By not having the section 126 extending beyond the bearing surface 118, the container 100 can be transported in an upright position prior to and during processing without requiring a support mechanism to keep 20 the container 100 from falling over, and results in cost savings by eliminating the support mechanism to hold the container upright. The base 108 of the container 100 provides the benefit of reduced internal vacuum pressure caused by the hot-fill process and allows the container to stably stand on a flat surface for transport between container processing machines. 1000351 FIGs. 3A-3G illustrate alternative exemplary embodiments for the structure of 25 the base 108 according to the present invention. Each of bases 308A-G includes features similar to those in base 108 of FlGs. 1A-1C. Most notably, FIGs. 3A-3G differ in the structure of the support braces 330A-G and in the ribs 332A-G from the previously described base 108. FIG. 3A illustrates a first wall 320A of base 308A including alternating flat protruding support braces 330A and flat recessed ribs 332A. FIG. 313 illustrates first wall 320B of a base 308B including 30 pyramidally shaped ribs 332B and trapeziodally shaped support braces 3303. FIG. 3C illustrates a first wall 320C of base 308C including multiple circularly shaped concentric ridges 340C. 8 WO 2007/047574 PCT/US2006/040361 FIG. 3D illustrates a first wall 320D of a base 308D that bows inward toward the interior of the container from a bearing surface 318D to the hinge 322D without any ribs or support braces. FIG. 3E illustrates a first wall 320E of base 308E including ribs 332E and support braces 330E. The support braces 330E narrow at the bearing surface 318E and at the hinge 322E and flare out 5 in the middle therebetween. The ribs 332E flare out at the bearing surface 318E and at the hinge 322E and narrow in the middle therebetween. FIG. 3F illustrates a first wall 320F including flat support braces 330F between ribs 332F each having three square concave indentations into the interior of the container. A base 308G as illustrated in FIG. 3G includes a bearing surface 318 and a first wall 320G having creases 328. The creases 328 in the first wall 320G are similar to 10 the creases 128 of the second wall 124 in the embodiment depicted in FIG. 1B. It is noted that FIGs. 3A-3G are exemplary embodiments of base structures according to the present invention, and that other embodiments having symmetrical, asymmetrical, non-circular, or other shapes may be used as will be appreciated by those skilled in the art. [000361 The container 100 may be formed of plastic materials known in the art. The 15 container 100 may have, for example, a one-piece construction and can be prepared from a monolayer plastic material, such as a polyamide, for example, nylon; a polyolefin such as polyethylene, for example, low density polyethylene (LDPE) or high density polyethylene (HDPE), or polypropylene; a polyester, for example polyethylene terephthalate (PET), polyethylene naphtalate (PEN); or others, which can also include additives to vary the physical 20 or chemical properties of the material. For example, some plastic resins can be modified to improve the oxygen permeability. Alternatively, the container 100 can be prepared fTom a multilayer plastic material. The layers can be any plastic material, including virgin, recycled and reground material, and can include plastics or other materials with additives to improve physical properties of the container. In addition to the above-mentioned materials, other materials often 25 used in multilayer plastic containers include, for example, ethylvinyl alcohol (EVOH) and tie layers or binders to hold together materials that are subject to delamination when used in adjacent layers. A coating may be applied over the monolayer or multilayer material, for example to introduce oxygen barrier properties. [000371 The container 100 may be formed by any plastic molding process. The 30 container 100 may be formed by a stretch blow molding process where warm gas is used to stretch a plastic preform into a container mold. The preform may have a threaded top, or may 9 use a continuous plastic tube. Blow molding the plastic tube may involve inserting a needle into the plastic tube, and forcing gas through the needle to expand the plastic tube to take the shape of a mold for a container. Additionally, other blow molding techniques may be used for forming 5 the container 100, including injection blow molding, stretch blow molding, or extrusion blow molding, as will be appreciated by those of skill in the art. [00038] 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 10 invention. Relative terminology and directional words, such as upper, below, interior, etc., are used in the application as a means of describing the present invention, and not of limitation. Nothing in this specification should be considered as limiting the scope of the present invention. AU 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 15 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. [0039I Throughout this specification and the claims which follow, unless the context 20 requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. [00401 The reference to any prior art in this specification is not, and should not be taken 25 as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in Australia. 10

Claims (18)

1. A method of compensating for vacuum pressure changes within a container, the container including a neck portion, a body portion, and a base portion, the base portion forming a bearing surface for the container and having a bottom end thereof with a hinge and a base wall, the base wall being adapted to be repositioned about the hinge from a first position to a second position, the method comprising: hot filling the container with a product; sealing the container with a closure; cooling the hot filled container; and repositioning the base wall about the hinge from the outward extending position to the inward extending position, thereby reducing the negative internal pressure of the container, wherein prior to said repositioning, the container is adapted to stand upright on a flat surface; and wherein the base wall includes a plurality of creases to facilitate repositioning thereof, the creases being adapted to flex during repositioning of a second wall portion.

2. A system for handling filled containers, each said container including a neck portion, a body portion, and a base portion, the base portion forming a bearing surface for the container and having a bottom end thereof with a hinge element, a base wall having a first wall portion and a second wall portion, and a section circumscribed by the second wall portion, the second wall portion and the section being adapted to be repositioned about the hinge element from a first position to a second position with substantially no movement of the first wall portion during the repositioning, the system comprising: 11 filling means for filling the containers with a product, the product being at an elevated temperature; sealing means for sealing the filled containers using a cap; vacuum creating means for creating a vacuum in each of the filled and sealed containers by cooling; conveying means for conveying the containers having vacuums created therein with the second wall portion and the section in a first position, the containers being conveyed such that their bearing surfaces stand on a flat surface, wherein, in the first position, no portion of the second wall portion and the section extend below the bearing surface of the base portion of the container; and repositioning means for repositioning the second wall portion and the section of each container from the first position to a second position partially to reduce the vacuum, the repositioning being done after the containers are conveyed by said conveying means, wherein the base wall includes a plurality of creases to facilitate repositioning thereof, the creases being adapted to flex during repositioning of the second wall portion.

3. The system of Claim 2, wherein, in the first position, no portion of the second wall portion and the section extend to the bearing surface of the base portion of the container.

4. The system of Claim 2, wherein said repositioning means is a mechanical device operable to apply a force to the section to reposition the second wall portion and the section from the first position to the second position.

5. The system of Claim 2, wherein, the second position of the section is arranged more toward the interior of container than the first position. 12

6. A method for handling a plastic container comprising: hot-filling the plastic container, the plastic container including a body and a base, the base forming a standing surface for the plastic container and including a bottom end with a moveable element, the moveable element being adapted to be inverted and including a plurality of creases to facilitate the inverting, the creases being adapted to flex during the inverting; capping the hot-filled plastic container; creating an internal vacuum in the hot-filled and capped plastic container by cooling; transporting the plastic container having an internal vacuum; and inverting the moveable element from a first position to a second position to reduce the internal vacuum.

7. The method of Claim 6, wherein during said hot filling, said capping, said creating a vacuum, said transporting, and said inverting, the moveable element is above the standing surface at all times.

8. The method of Claim 6, wherein during said hot filling, said capping, said creating a vacuum, said transporting, and said inverting, the moveable element does not extend below the standing surface.

9. The method of Claim 6, wherein the bottom end of the base further includes a non moveable element and a hinge element, the non-moveable element sloping in a direction from the standing surface to the moveable element toward the interior of the container and 13 circumscribing the hinge element and the hinge element circumscribing the moveable element, said inverting including moving the moveable element from a first position to a second position, said moving being performed such that substantially no movement of the non-moveable element occurs, and such that the moveable element moves about the hinge element the non-moveable element sloping in a direction from the standing surface to the moveable element toward the interior of the container.

10. The method of Claim 6, wherein said transporting includes the standing surface of the plastic container resting on a flat surface, with the moveable element at or above the standing surface.

11. The method of Claim 1, wherein in the first position no portion of the base wall extends to the bearing surface of the base portion of the container.

12. The method of Claim 1, wherein in the first position no portion of the base wall extends past the bearing surface of the base portion of the container.

13. The method of Claim 1, wherein said repositioning involves a mechanical device operable to apply a force to the base wall to reposition the base wall from the first position to the second position.

14. The method of Claim 1, wherein the second position of the base wall is arranged more toward the interior of container than the first position. 14

15. The method of claim 9, wherein the moveable element includes radial ribs to increase rigidity.

16. The method of claim 1, wherein the first position extends to a position coplanar with the bearing surface but no lower.

17. The system of claim 2, wherein, in the first position, a portion of the section is coplanar with the bearing surface.

18. The method of claim 6, wherein the moveable element is inverted to a position coplanar with the bearing surface but no lower. 15