Method of processing a plastic container with mechanical and self-activating base panels to increase internal pressure

Abstract

A method of processing a plastic container to increase internal pressure including blow-molding the container to comprise an invertible panel in the base and a standing ring, hot filling and sealing the container, feeding the container into an apparatus with a holding device and forcing a volume reduction and pressure increase into the container, and stacking the containers in bulk pallets on top of one another to increase top load and create a positive pressure within the distribution load of containers.

Description

[0001] METHOD OF PROCESSING A PLASTIC CONTAINER WITH MECHANICAL AND SELF-ACTIVATING BASE PANELS TO INCREASE INTERNAL PRESSURE

[0002] FIELD OF THE INVENTION

[0003] 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 surrounded by a peripheral pressure panel. The present invention also relates to methods of making and processing containers having a peripheral pressure panel circumscribing an invertible vacuum panel deeply set into the base of the container.

[0004] BACKGROUND OF THE INVENTION

[0005] The following Patent Applications are incorporated herein by reference in their entirety: US 3,843,005 and US 3,949,034 issued to Uhlig; US 4,318,882 issued to Agrawal; US 4,465,199 issued to Aoki; EP1069983 issued to Valliencourt; US 6,230,912 issued to Rashid; US 8,584,879 issued to Melrose and commonly owned by the assignee of the present invention; US 8,047,388 issued to Kelley and commonly owned by the assignee of the present invention; US 8,636,944 issued to Kelley and commonly owned by the assignee of the present invention; US 8,444,002 issued to Schneider and commonly owned by the assignee of the present invention; US 9,994,378 issued to Wurster and commonly owned by the assignee of the present invention; US 9,150,320 issued to Wurster and commonly owned by the assignee of the present invention; US 8,881,937 issued to Derrien; US 8,292,612 issued to Langlois; US 8,616,395 issued to Patcheak; US 9,688,013 issued to Derrien; US 9,676,140 issued to Deau; and, US 10,232,545 issued to Maki; and US 12,162,204 issued to Wurster. 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 degrees 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.

[0006] To compensate for the change in volume inside the container it is known to provide pressure compensating features in various locations on the container sidewall including the dome, the barrel, and the bottom portion. The pressure compensating features move in response to pressure changes to decrease the volume as needed through deflecting inwardly under vacuum pressure.

[0007] As disclosed in Patcheak a container may have a plurality of horizontal ribs 602 in the sidewall and a base portion having vacuum absorbing features that is moveable under a vacuum force and does not require a mechanical force to move the base upwardly to remove vacuum. The Patcheak base panel is also configured with a series of indentations to assist flexibility and is able to be hot filled and cooled leaving a residual vacuum in the container that applies a force that subsequently flexes the base panel inwardly. Patcheak also discloses the ribs 602 collapse under the vacuum force created during cooling. Patcheak further discloses that once the container has been cooled and under a vacuum load the container reaches a point where external forces such as top load or side load would beneficially result in a pressurization of the container that would help the stacked container to resist external forces. Patcheak identifies that the addition of a top load, for example by bulk packing containers onto pallets once the containers are cooled, may beneficially result in the horizontal ribs 602 compressing further and allowing the plastic container to reach a state wherein the plastic container is supported in part by the product inside when exposed to excessive top load forces thereby preventing permanent distortion. A problem exists with Patcheak, however, in that the containers are under moderately strong vacuum pressure after processing and cooling and immediately prior to bulk pallet stacking. Such containers with ‘active’ vacuum panels in the base, wherein the panel can move in under vacuum results in a final container still exhibiting relatively strong residual vacuum inside the container while in distribution. The panel is in an inward position under the vacuum force, and the container is subsequently stacked in pallets while under a vacuum force.

[0008] During bulk stacking, as disclosed by Patcheak, the downward pressure of the top load increases the internal pressure inside the container as the ribs collapse downwardly further from their positions under vacuum following labelling, and a further volume reduction is enforced on the container - driving up the internal pressure due to the container being sealed. However, a certain amount of the potential for increased pressure is in fact relieved by the capacity of the base to move back outwards again under the increased top load (reducing the amount of vacuum pressure as the pressure increases). The reversal of the vacuum panel reduces the potential increase in pressure that would otherwise be available if the panel was instead configured to be resistant to, or locked against, moving outward from the inverted position.

[0009] Therefore, there remains a need in the art for plastic containers and a different processing method to Patcheak that overcome the aforementioned shortcomings of the prior art.

[0010] It is an object of the invention to provide a container and a method of processing a container, which overcome or at least partially ameliorate some of the abovementioned drawbacks or which at least provides the public with a useful choice.

[0011] In this specification, where reference has been made to external sources of information, including patent specifications and other documents, this is generally for the purpose of providing a context for discussing the features of the invention. Unless stated otherwise, reference to such sources of information is not to be construed, in any jurisdiction, as an admission that such sources of information are prior art or form part of the common general knowledge in the art.

[0012] For the purpose of this specification, where method steps are described in a sequence, the sequence does not necessarily mean that the steps are to be chronologically ordered in that sequence, unless there is no other logical manner of interpreting the sequence.

[0013] BRIEF DESCRIPTION OF THE INVENTION

[0014] The present invention relates to an ‘as-blown’ polymeric or plastic container having two moveable or invertible pressure portions or panels located in the container base and a method of processing the container to increase top-load resistance and to increase hot-fill container performance. According to a preferred embodiment there is provided a radially external high performance self-activating first pressure panel capable of adjusting longitudinal position under varying internal container pressures, and a radially internal second pressure panel that is moveable under mechanical force to increase pressure within the container after filling and sealing of the as-blown container, wherein the first pressure panel radially circumscribes the second pressure panel. After filling the container with a heated liquid and capping, the first pressure panel is moveable outward or downward to relieve internal positive pressure and stress within the container, and then moveable inward or upward to relieve internal pressure reduction or vacuum pressure following a cooling of the heated contents. The second pressure panel is then mechanically forced from an initial, outwardly-inclined position, to an inverted, inwardly-inclined position, in order to force a reduction in the volume of the sealed container and accommodate for vacuum forces caused by a cooling of heated liquid contents within the container. Upon mechanically forcing the second pressure panel inward or upward, the first pressure panel is configured to move back outward or downward again under the increased pressure, to provide for additional vacuum compensation as the liquid contents cool further or the liquid product ages and permeates the sidewalls of the plastic container. The second pressure panel may be set deeply into the base of the container above the first pressure panel in the blowmolding part of the container processing, such that no portion of the second pressure panel extends beyond the standing ring or surface, regardless of whether the second pressure panel is in the initial position or the inverted position. Further, the first pressure panel can be configured to provide a radially alternating contact or standing surface or ring. This configuration can allow the container to be supported by the standing ring of the first pressure panel regardless of whether the second pressure panel is in the initial position or the inverted position. After filling, the container is further processed by feeding the container into an apparatus that forces a volume reduction while stabilizing the container resulting in an increase in pressure. The container is then stacked in bulk pallet configurations to further increase internal pressures prior to distribution and sale of products.

[0015] Other prior art plastic containers suitable for containing a liquid are disclosed in U.S. Pat. Nos. 5,261,544 issued to Weaver, Jr.; and U.S. Pat. No. 5,908,128 issued to Krishnakumar et al, both of which are incorporated in their entirety in the present specification.

[0016] As disclosed in Weaver, Col. 5, lines 26 - 29, a polymeric container should be blow-molded with a minimum thickness of at least about 10 mils (0.01 inches or 0.254 mm). During blow-molding and heat-setting a container it should be recognized that in forming a container with an average thickness by total container weight of about 10m ils will inevitably lead to thinner portions and container forming performance is generally compromised when the walls fall below a local area thickness of about 8 mils ( 0.008 inches or 0.2032mm), thus aiming for blow-molding an average thickness of about 10mils should lead to a container having at least about 8 mils in the thinnest regions. Generally, however, hot fill containers also need an amount of sidewall thickness to withstand the mechanical forces generated by vacuum inside during processing the containers. As disclosed in Krishnakumar, Col. 4, lines 17 - 24, a container of approximately 20 ounces in volume made from 'bottle grade' PET (having about 1.5% comonomer and an intrinsic viscosity of about 0.80) may have a side-wall thickness on the order of 0.4 mm, or 15.7 mils, in order to withstand containing a previously heated liquid.

[0017] One object of the present invention is to provide a first pressure panel in the base of a container that has a portion that is relatively conducive to movement under both positive pressure and vacuum pressure, and a second pressure panel that has a portion that is relatively resistant to substantial movement under vacuum force alone and relatively resistant to substantial movement under positive pressure. An object is to provide an apparatus to hold and stabilize the container after hot-filling and sealing and to mechanically invert the second pressure panel in order to achieve a greater, forced volume reduction inside the container than is available in Patcheak, and instead create a positive pressure within the container prior to then also bulk pallet stacking multiple such containers. A further embodiment is to provide a processed container with an inverted base portion configured to resist outward movement under the increase in pressure during bulk pallet stacking, and a portion configured to move under increasing or decreasing pressures in order to achieve and modulate a greater increase in internal pressure under top load forces of bulk pallet stacking than provided in Patcheak.

[0018] The increase in pressure within the container created under bulk pallet stacking is applied unequally throughout an entire vertical load, and analysis and testing has demonstrated so called ‘self-activating’ vacuum bases as disclosed in Patcheak only provide for a reduction in vacuum within the pallet load of containers, and not to provide a positive pressure during bulk pallet stacking, especially within a single layer height. The present invention, however, provides for a positive pressure to be created inside the containers during first pallet stacking of such containers in order to support the containers to a greater degree.

[0019] Table A below shows example analysis and testing of a set of self-activating bases versus containers processed according to the present invention. Bottles were hot-filled, cooled, and in the case of the present invention the bases were mechanically processed in the manner herein disclosed, then tray packed and stacked 7 layers high in corrugate cardboard used to represent trays. Data loggers were placed in various bottles in the bottom layer of the stack (where the most top load would be exhibited) and 6 layers were stacked on top of the bottom layer simulating a completed pallet.

[0020] TABLE A

[0021] Container with Container with Self-Active Mechanically Inverted Base Base

[0022] Average Pressure prior to Pallet

[0023] Stack (Bottom Layer) -3.26psi 0.005 psi

[0024] Average Increase in Pressure

[0025] during Pallet Stack (Bottom Layer)

[0026] 0.582 psi 0.680psi

[0027] Average Pressure during Pallet

[0028] Stack (Bottom Layer) -2.56psi 0.685 psi

[0029]

[0030] Containers processed according to the present invention, by comparison to Patcheak, have much higher pressures prior to pallet stacking, often a positive pressure. Advantageously, and additionally, the bases of the present invention are configured to partially resist outward movement when a top load is applied, unlike the bases of Patcheak that are able to move back out under a pressure increase and therefore do not offer resistance to the early top load force application. The bases of the present invention provide resistance to the applied top load of pallet stacking, and therefore there is an increase in internal pressure at a faster rate and to a greater amount. Containers processed according to the present invention exhibit much higher pressures beneficially providing for containers having a positive pressure generally when stacked two pallets high.

[0031] According to one exemplary embodiment, the present invention relates to a method of processing a plastic container wherein a substantial amount of vacuum is mechanically removed from the container after cooling and prior to pallet distribution, and through a locking of the second pressure panel in the container base in the inverted position a much lower vacuum remains, or even a positive pressure in the cooled container. The container is then bulk packed and a further increase in internal force is provided through the application of top load during storage and distribution. Through the processing of the container according to the present invention, a bulk pallet of containers will therefore more quickly achieve higher pressures than achievable in the prior art, providing a greater amount of support from the incompressible liquid product within the container.

[0032] 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 two substantially transversely-oriented pressure panels located in the lower portion, transversely or radially separated from each other. The pressure panels can be movable between an outwardly inclined or downward position and an inwardly inclined or upward position, moving or inverting in the longitudinal or vertical direction, to compensate for a change of pressure inside the container. The standing surface can define a standing plane, and the high performance first pressure panel can be located between an outer diameter and an inner diameter, and configured to provide alternating standing base radii for the standing plane and for when the second pressure panel is in the outwardly inclined or inwardly inclined positions.

[0033] 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 heated and 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; (c) displacing the base mold portion with respect to the first and second side mold portions to form a first transverse pressure panel circumscribing a second pressure panel deeply set within a base portion of the plastic container; (d) providing the plastic container having an upper portion including a finish, a sidewall, a lower portion including a base defining a standing surface, and the transversely-oriented pressure panels located in the base for further processing on a hot filling line; (e) introducing heated liquid contents into the plastic container within a filling apparatus with the first and second pressure panels located in an outwardly-inclined or downward position between the standing surface and the upper portion; (f) capping the plastic container; (g) stabilizing the container in an apparatus for moving the second pressure panel to an inwardly-inclined position above the standing surface to increase the pressure, and moving the first pressure panel to an outward position wherein the standing base radius is at a controlled minimum length to preserve a minimum ‘tilt angle’ for vertical stability of the container during processing; and (h) stacking the container among multiple other containers in a bulk pallet arrangement several layers high. 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.

[0034] According to an aspect, the invention may be said to broadly comprise a method of processing a plastic container to increase internal pressure including blow-molding the container to comprise two invertible panels in the base and a standing ring, hot filling and sealing the container, feeding the container into an apparatus with a holding device and forcing a volume reduction and pressure increase into the container, and stacking the containers in bulk pallets on top of one another to increase top load and create a positive pressure within the distribution load of containers.

[0035] 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.

[0036] As used herein the term “and / or” means “and” or “or”, or both.

[0037] As used herein “(s)” following a noun means the plural and / or singular forms of the noun. The term “comprising” as used in this specification and claims means “consisting at least in part of.” When interpreting statements in this specification and claims which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The invention will now be described by way of example only with reference to the drawings in which: FIG. 1a is a front 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;

[0040] FIG. 1 b is a perspective view of the plastic container of FIG. 1 a;

[0041] FIG. 2 is a side, sectional view of the plastic container of FIGs. 1 , shown with the pressure panel in the initial, outwardly-inclined position;

[0042] FIG. 3 is a side, sectional view of the plastic container of FIGs. 1 , shown with the pressure panel in an inverted, inwardly-inclined position;

[0043] FIG. 4 is a bottom view of the plastic container of FIGs. 1 ;

[0044] FIG. 5 is a perspective view of another exemplary embodiment of a plastic container according to the present invention, shown with the first and second pressure panels in the initial, outwardly-inclined position;

[0045] FIG. 6a is a bottom view of the plastic container of FIG. 5;

[0046] FIG. 6b is a cross-section view of the plastic container of FIG 5;

[0047] 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 first and second pressure panel in an initial, outwardly-inclined position;

[0048] FIG. 8 is a perspective view of a portion of a plastic container according to yet another exemplary embodiment of the present invention, shown with the first and second pressure panels in an initial, outwardly-inclined position;

[0049] FIG. 9 is a side, sectional view of a portion of the plastic container of FIG. 5, shown with the pressure panel in the initial, outwardly-inclined position;

[0050] FIGS. 10a - 11f schematically illustrate an exemplary method of processing a plastic container according to the present invention;

[0051] FIGS. 11a - 11f schematically illustrate an exemplary method of processing a plastic container according to the present invention;

[0052] FIGS. 12a -12f schematically illustrate an exemplary method of forming plastic containers according to the present invention; FIGS. 13 - 16 are cross-sectional views of a mold assembly with electrically heated and mol base supports illustrating an exemplary method of forming the plastic containers according to another embodiment of the present invention;

[0053] FIGS. 17 - 23 schematically illustrate an exemplary method of forming plastic containers according to another embodiment of the present invention;

[0054] FIGS. 24-25 are flow charts depicting methods of making a container, constructed and operative in according with an embodiment of the present invention;

[0055] FIGS. 26a - 26c show additional side sectional views of a container according to another embodiment of the invention;

[0056] FIGS. 27a - 27b show additional side sectional views of a container according to another embodiment of the invention;

[0057] FIG. 28 is a side sectional view of a container according to one embodiment of the invention prior to bulk pallet stacking;

[0058] FIG. 29 is a side sectional view of the container of FIG. 28 during bulk pallet stacking;

[0059] FIG. 30 is a front side elevation view of a handling system that combines single containers with a container handling device according to an embodiment of the invention;

[0060] FIGS. 31a - 31b show a plan and front view of a base plate holder portion of a container holding device according to an embodiment of the invention;

[0061] FIG. 32 is a schematic plan view of an activation portion of the handling system according to an alternate embodiment of the invention;

[0062] FIG. 33 is a detailed plan view of the activation portion of the handling system of FIG. 32;

[0063] FIG. 34 is an unfolded elevation view of a section of the activation portion of FIG. 32 illustrating the activation of the container and the removal of the container from the container holding device;

[0064] FIG. 35 is an enlarged view of a section of the activation portion of FIG. 34; FIG. 36 is an enlarged view of the container holder removal section of FIG. 34; FIGS. 37a - 38b illustrate side sectional views of another embodiment of the invention;

[0065] FIGS. 39a - 39e show additional front and side sectional views of a container according to another embodiment of the invention; and,

[0066] FIGS. 40a - 40f show additional front, side and sectional and elevation perspective views of a container according to another embodiment of the invention.

[0067] DETAILED DESCRIPTION

[0068] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various principles of the present invention. However, those skilled in the art will appreciate that not all these details are necessarily always required for practicing the invention.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] Additionally, the vacuum panels in the sidewall can undesirably detract from the appearance and feel of the container, and lim it the design possibilities for the container.

[0073] Typically at a bottling plant containers are filled with a hot liquid and then capped before being subjected to a cold water spray in a cooling tunnel, 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. A problem exists in such single pressure panel containers, however, in that there is little ability for the container to absorb further vacuum after the pressure panel has been inverted. Any further vacuum build up, for example during extended shelf life causes increased vacuum pressure in the container. The present invention relates to additional embodiments of this concept in which a high performance self-activating first pressure panel radially or circumferentially surrounds a second pressure panel set deeply into the base of the container, such that no portion of the second pressure panel extends beyond a radially alternating standing ring provided by the moveable first pressure panel, regardless of whether the second pressure panel is in the initial position or in the inverted position. This configuration can allow the container to be supported by the alternating standing ring regardless of whether the pressure panel is in the initial position or the inverted position and also provides for substantial vacuum compensation within the first pressure panel after inversion of the second pressure panel as the increased pressure absorbed by the first pressure panel as it moves downwardly is released under further cooling or aging of the product inside and modulates the amount of vacuum build-up potential. This also has the advantage of allowing for increased design options in hot fill containers, for example to allow for the second pressure panel to be configured for a smaller compensation amount in the presence of flood filling of the containers, in order to reduce or prevent product spilling on the consumer when the cap is initially removed. By way of example, the container can be configured to provide for a small vacuum upon final cooling of the product, with the high performance self-activating panel providing for further vacuum compensation during product aging throughout distribution. During palletization the container achieves a positive pressure nonetheless as the vacuum present at the time of bulk stacking is negligible when compared to prior art such as Patcheak.

[0074] 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 bumper region 83, a chime 82, a base 20, and a sidewall 22 extending between the upper portion 12 and the lower portion 18. The base 20 in the ‘as-blown’ container 10 can define a first standing surface 21a and a second standing surface 21b. The first standing surface defines a standing or contact plane that is generally perpendicular to the central longitudinal axis A-A of the container 10. A first pressure panel 23 comprises an inside radius 23r1 and an outside radius 23r2 and have an outside diameter 21 d and an inside diameter 21c. As shown in FIG 2 the ‘as-blown’ configuration of the first pressure panel 23 may comprise a contact plane on the inside radius 23r1 and have a first standing surface 21a. In this configuration the first pressure panel 23 is slightly downwardly inclined relative to the contact plane, and preferably less than about 15 degrees downwardly inclined, and more preferably less than about 10 degrees downwardly inclined, and most preferably less than about 5 degrees downwardly inclined. In this preferred embodiment and particularly shown in FIG. 4 the high-performance pressure panel has an inside diameter 21c that is approximately about 65% of the maximum container diameter 21 dmax, and an outside diameter 21 d that is approximately about 94% of the maximum container diameter 21 dmax. It is an object of the invention to provide the radially external pressure panel within margins of about 60% up to 100% of the maximum container diameter 21 dmax thus providing maximum pressure adjustment performance while allowing generous area radially inside the inside diameter 21c for the placement of another separately functioning panel region closer to the longitudinal axis. In other embodiments the first pressure panel may substantially flat or upwardly inclined as will be discussed below. The first pressure panel 23 is 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).

[0075] 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 comers of the polygon are typically rounded or chamfered. Although the container 10 is shown as having reinforcing ribs or rings 602 in the sidewall 22 to resist paneling, dents and other unwanted deformation of the sidewall, particularly under vacuum force, 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) or may comprise only an upper and lower reinforcing rib or ring 602 with a sidewall between that is substantially free of reinforcing features.

[0076] As best seen in FIG. 4, a central portion of the base 20 comprises a second pressure panel 25. The second pressure panel can include a plurality of reinforcing ribs 241 , however other embodiments with or without the reinforcing ribs 241 are also anticipated. The second pressure panel may also include a central dimple or push up 248 having an external, underside surface 248’ configured to receive a mechanical rod or similar projection device.

[0077] The lower portion 18 of the container 10, and particularly the base 20, can include two substantially transversely-oriented pressure panels 23 and 25. The pressure panel 23 can be moved by changing internal pressures between an outwardly-inclined position and an inwardly-inclined position in order to change the internal volume of the container 10 and compensate for any pressure forces created within the container during the filling process. For example, the pressure panel 23 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.

[0078] As best seen in the sectional views of FIGS. 2 and 3, the pressure panel 25 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 25 is located in the outwardly-inclined position (FIG. 2) or the inwardly-inclined position (FIG. 3). In other words, the entire pressure panel 25 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).

[0079] 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 forms the chime region 82 and that extends from the lower end of the sidewall 22 to the standing surface 21. The standing surface may be a ring or annular portion as shown in FIG. 1 b, or may be discontinuous as shown in FIG. 5. The second pressure panel 25 is deeply set into the lower portion 18 of the container 10 via an inner wall 32 that extends from the standing surface 21 adjacent to the inside radius 23r1 of the first pressure panel 23 to an outer periphery 242 of the second pressure panel 25. The inner wall may therefore comprise an instep or hollow recessed portion between the first pressure panel 23 and the second pressure panel 25 and the standing surface 21. In the exemplary embodiment shown, the inner wall 32 comprises two annular rings stacked upon each other and angled at different amounts away from parallel to the longitudinal axis A of the container 10, and provides the recessed portion with a compound concave annular ring shape; however, other configurations and / or inclinations of the inner wall 32 are possible that are not concave annular ring structures, and may have different angles varying between about 0 -70 degrees with respect to the longitudinal axis. 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 25 deeply into the lower portion 18.

[0080] 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.

[0081] 5 and 6, the container 10' can have a standing surface 21, inner wall 32', and outer wall 30' that are discontinuous.

[0082] The second pressure panel 25 comprises an inner annular wall having an inner periphery 244 and the outer periphery 242, and is set, with respect to the longitudinal axis and the opening into the container, with at least a portion at an outward or downward angle prior to filling with a heated liquid. The first pressure panel 23 includes support or foot portions 230 and the inner wall portions 32' extend from the standing surfaces 2T to the inner annular wall or second pressure panel 25. . In the example shown there may be about 21 support or foot portions 230. The number of support or foot portions 230 can vary in number but preferable are above 10 and below 30, although fewer or more feet may be considered. More particularly better circumferential container stability and balance is achieved when the number of feet are above 14 and more particularly when above 18 feet. Radial webs or straps 246 are uniformly spaced apart and separate each support 230. The web surface is closer to the finish than the footed contact surface, or expressed another way, the webs 246 are longitudinally displaced above the footed contact surface 2T. In addition, each support 230 has a larger arcuate extent than that of each radial web 246 in order to maximise the surface area of the contact surface, however alternative configurations may minimize the surface area of the contact surface as shown in FIG 7 and 8 wherein each support 230 may have a lesser arcuate extent that that of each radial web 246. The second pressure panel or inner annular wall 25 extends within the concave outer annular wall 30'. The outer periphery 242 of the second pressure panel 25 merges with the inner wall 32' separating the first pressure panel 23 from the second pressure panel 25. Each of the webs 246 on the first pressure panel 23 extends between the supports 230 and connects to the container sidewall 22 in the lower portion 18 at an elevation above the horizontal plane "P" extending through the standing surface 21 to form radius 202 such that web surface 246 is visible from a side of the container. Preferably the second pressure panel 25 and the central dimple or push up 248 merge via an annular hinge 250 at the foot of the push-up, comprising radius 251.

[0083] In order to facilitate movement (e.g., folding) of the second pressure panel 25 between the outwardly-inclined position of FIG. 2 and the inwardly-inclined position of FIG. 3, pressure panel 25 can include a decoupling or hinge structure 361 that is located between the inner wall 32 and the pressure panel 25. In the exemplary embodiment shown, the hinge structure 361 comprises a substantially radiused, nonribbed region, that is susceptible to folding, and centred around the outer periphery 242 of the second pressure panel 25, however, other configurations of the hinge structure, such as a substantially flat portion, are possible.

[0084] Referring now particularly to FIG. 9, the pressure panel 25 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 25 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 25 (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.

[0085] In order to maximize the amount of vacuum compensation from the second pressure panel 25, 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. 9a, 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 30 degrees, and preferably is between about 30 degrees and about 45 degrees, but may be much greater than about 45 degrees, and for example between about 45 degrees and 80 degrees as the second pressure panel is configured to generally resist inversion under vacuum pressure alone, and is configured instead to require mechanical assistance to force inversion of the panel 25. According to this embodiment, the initiator portion 40 can be at a second angle beta, with respect to standing plane P, that may be at least 10 - 20 degrees less than the first angle alpha, but may be considerably less than this, and even angled in the opposite direction to the angular direction of the control portion e.g. toward the upper portion of the container. 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 50 degrees, it will provide an angular change of approximately 100 degrees. It will be appreciated that through the forced inversion of the panel 25 by utilizing a mechanical device located against the underside 248’ of the push up 248, then the initiator can be removed altogether and an entirely conical control portion can be configured as the panel 25 can be moved simply by increasing the force applied using the mechanical inverter. The configuration utilizing an initiator portion provides an optional reduction in the mechanical force required to invert the panel 25.

[0086] Referring to FIGS. 10a-1 Of, 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 first pressure panel 23 in a slight outwardly-inclined position such that the container rests on a first standing surface 21a, although it will be appreciated that the first pressure panel 23 could be configured to rest on both standing surfaces 21a and 21 b, or could be configured to be blow -molded initially to stand on the second standing surface 21b. Separated from the first pressure panel 23 by an inner wall 32, the second pressure panel 25 is configured to be vertically above the contact plane and as molded in the outwardly-inclined position. According to this embodiment, after filling the as-molded container with a heated liquid, and capping the container, the container is placed on a conveyor for further processing. An internal pressure builds up inside the headspace of the sealed container, especially after the container is turned on its side, or upside down, in order to sterilize the inside surface of the cap with the heated liquid. Prior to cooling, the internal pressure that builds within the sealed container is compensated for by an outward or downward movement of the first pressure panel 23 to a second position. Importantly, pressure panel 23 maintains the first standing surface 21a to prevent the problem of ‘base roll out’ causing vertical stability problems as seen on much prior art. Pressure panel 23 is configured to substantially maintain the inside radius 23r1 and the initial standing diameter 21c of the first standing surface 21a. The container is configured to grow in height, not only through some expansion of the horizontal ribs 602, but also by the increase in the downward angle of the first pressure panel 23. The increase in the downward angle of the first pressure panel 23 provides some compensation for the increased internal pressure. The second pressure panel 25 is configured to be moveable substantially only through a mechanical force and remains in the as-blown shape, but may be forced toward the contact plane to a degree.

[0087] Once the heated contents have sterilized the inside of the container, after approximately 60 - 90 seconds post filling, the sealed container is typically conveyed into a cooling tunnel or the like for a forced cooling operation. After cooling to about 30-45 degrees C from an initial 80-87degrees C as filled, a vacuum pressure builds up within the container, and the first pressure panel 23 compensates for the vacuum pressure by moving upwardly to a third position as can be seen in FIG 10c along with some contraction of the horizontal ribs 602. The first pressure panel is configured to alternate standing surfaces under the vacuum force, providing for the container to resth on a second standing surface 21b that in fact provides an even superior contact diameter. The first pressure panel 23 provides significant vacuum compensation, allowing for much better control over deformation in the sidewalls of the lightweight container 10 prior to mechanical inversion of the second pressure panel 25. Thus, the container is in a substantially stable configuration exiting the cooling tunnel, with excellent vertical stability.

[0088] Following cooling, the sealed and stable container is conveyed under vacuum to an inverter apparatus for forced volume reduction through mechanically inverting the second pressure panel 25 as seen in FIG 10d. Typically at this point in processing the container, the mechanical inversion of the second pressure panel 25 creates a positive pressure within the container, as the temperature is usually above ambient temperature by about 15 degrees C as the container has not been completely cooled at this point. The first pressure panel 23 compensates for the forced increase in internal pressure following the mechanical inversion of the second pressure panel by moving to a fourth position and alternating contact surfaces again to secure vertical stability of the container through provision of the first standing surface 21a. Additionally there may be some expansion of the horizontal ribs 602. Typically, prior to labelling therefore, the container is highly stabilized and under some positive internal pressure with the first pressure panel 23 in an outward position and resting on the first standing surface 21a. The container is labelled and then conveyed away for distribution.

[0089] As can be seen in FIG 10e, once the container reaches ambient temperature during distribution there may be substantially ambient pressure within the container (as shown) with the container still resting on the first standing surface 21a. Alternatively, either a positive internal pressure may be configured - with the container resting on the first standing surface 21a, or a vacuum pressure may be configured - with the container resting on the second standing surface 21 b, or an inbetween state where the container rests largely on any portion of the first pressure panel 23. Lightweight plastic containers that are in distribution for extended periods of time lose water vapor through transmission through the sidewalls, and over a period of time may lose a good percentage of liquid volume creating a further drop in internal pressure as seen by way of example in FIG1 Of. A container that is configured to have approximately ambient pressure once cooling to ambient temperature, as provided by way of example only in FIG10e, will therefore experience a vacuum build up over about 6 months of expected distribution. The first pressure panel 23 is configured to compensate for this increased water vapor transmission and change in pressure by moving to a fifth position and alternating again to the second standing surface 21b if a pressure drop inside the container required this amount of compensation. Typically in prior art, after mechanical inversion there is little vacuum compensation available in the base, without the use of the present invention.

[0090] Referring to FIGS. 11a-11 f, a further 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 first pressure panel 23 in a slight outwardly-inclined position such that the container rests on the footed portions configured within the first pressure panel and providing a first standing surface 21a on the lowest touch point of the footed portions. This has the beneficial effect of reducing the largest standing surface diameter but increasing the subsequent smaller standing surface diameter, which is the more critical standing surface diameter to protect during internal pressure experienced in the filled and sealed container prior to cooling. In this embodiment the contact plane of the container 10 is not defined by the inside radius of the pressure panel 23, which still alternates as described in FIGs 10a-f, but by the footed contact surfaces. Accordingly, the sequence of alternating standing surfaces differs in this preferred embodiment. Separated from the first pressure panel 23 by an inner wall 32, the second pressure panel 25 is configured to be vertically above the contact plane and as molded in the outwardly- inclined position. According to this embodiment, after filling the as-molded container with a heated liquid, and capping the container, the container is placed on a conveyor for further processing. Referring to FIG 11b, an internal pressure builds up inside the headspace of the sealed container, especially after the container is turned on its side, or upside down, in order to sterilize the inside surface of the cap with the heated liquid. Prior to cooling, the internal pressure that builds within the sealed container is compensated for by an outward or downward movement of the first pressure panel 23 to a second position. Importantly, in this configuration the contact surface provided by the footed portions alternates to a position closer to the longitudinal axis, but in a position radially external to the inside radius 23r1 of pressure panel 23, and the footed portion maintains the first standing surface 21a to prevent the problem of ‘base roll out’ causing vertical stability problems as seen on much prior art. Pressure panel 23 is configured to substantially maintain the inside radius 23r1 as it angles further downward, and the initial standing diameter 21 d of the first standing surface 21a in this embodiment is reduced by the rotating footed portions alternating contact position and providing a second standing surface 21b, which is diametrically larger than the inside radius 23r1. The container is configured to grow in height, not only through some expansion of the horizontal ribs 602, but also by the increase in the downward angle of the first pressure panel 23. The increase in the downward angle of the first pressure panel 23 provides some compensation for the increased internal pressure. The second pressure panel 25 is configured to be moveable substantially only through a mechanical force and remains in the as-blown shape, but may be forced toward the contact plane to a degree.

[0091] Once the heated contents have sterilized the inside of the container, after approximately 60 - 90 seconds post filling, the sealed container is typically conveyed into a cooling tunnel or the like for a forced cooling operation. After cooling to about 30-45 degrees C from an initial 80-87degrees C as filled, a vacuum pressure builds up within the container, and the first pressure panel 23 compensates for the vacuum pressure by moving upwardly to a third position as can be seen in FIG 11c along with some contraction of the horizontal ribs 602. The footed portions comprised within the first pressure panel are configured to alternate standing surfaces again under the vacuum force, providing for the container to rest again on the first standing surface 21a, but preferably in a wider diameter format than in the as blown position that in fact provides an even superior contact diameter. The first pressure panel 23 provides significant vacuum compensation, allowing for much better control over deformation in the sidewalls of the lightweight container 10 prior to mechanical inversion of the second pressure panel 25. Thus, the container is in a substantially stable configuration exiting the cooling tunnel, with excellent vertical stability.

[0092] Following cooling, the sealed and stable container is conveyed under vacuum to an inverter apparatus for forced volume reduction through mechanically inverting the second pressure panel 25 as seen in FIG 11d. Typically at this point in processing the container, the mechanical inversion of the second pressure panel 25 creates a positive pressure within the container, as the temperature is usually above ambient temperature by about 15 degrees C as the container has not been completely cooled at this point. The first pressure panel 23 compensates for the forced increase in internal pressure following the mechanical inversion of the second pressure panel 25 by moving to a fourth position and the footed portions alternating contact surfaces again to secure vertical stability of the container through provision again of the second standing surface 21b. Additionally there may be some expansion of the horizontal ribs 602. Typically, prior to labelling therefore, the container is highly stabilized and under some positive internal pressure with the first pressure panel 23 in an outward position and the container contact plane defined by the footed portions resting on the second standing surface 21b. The container is labelled and then conveyed away for distribution.

[0093] As can be seen in FIG 11e, once the container reaches ambient temperature during distribution there may be substantially ambient pressure within the container (as shown) with the container now resting again on the first standing surface 21a, unlike the configuration in FIGs 10a-f. Alternatively, either a positive internal pressure may be configured - with the container resting on the second standing surface 21b, or a vacuum pressure may be configured - with the container resting on the first standing surface 21a but with a larger diameter. Referring to FIG11 f, the first pressure panel 23 is configured to compensate for the increased water vapor transmission expected over an extended shelf life and change in pressure by moving to a fifth position, but in this embodiment retaining and improving the first standing surface 21 a to a larger diameter if a pressure drop inside the container required this amount of compensation. Typically in prior art, after mechanical inversion there is little vacuum compensation available in the base to compensate for extended shelf-life positions, without the use of the present invention.

[0094] 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. As stated above, the containers according to the present invention may be manufactured with a second base panel 25 extending above a first base panel 23 providing a configuration wherein the first pressure panel 23 has a radially alternating standing surface, providing for various degrees of protected container stability during the filling operations.

[0095] A particularly preferred embodiment of the present invention includes providing a container that is vertically geometrically stable and able to be conveyed easily on a filling line, wherein the radially alternating contact surface of the first pressure panel provides for some base roll out to occur without compromising vertical stability throughout the filling line. In this embodiment the second base panel is manufactured to extend only above the standing ring, wherein there still remains a need to provide a holding device during the process of mechanically inverting the second pressure panel in the base, and wherein the holding device may for example be fixed in place within the inverting apparatus, providing less complexity to the manufacturing process of both blowing and filling of the container. This preferred embodiment also comprises mechanically forcing a volume reduction in the container during processing in order to increase the internal pressure within the container to create greater stability within the container in distribution. It is well known in the art, that the higher the container pressure, the more rigid the sidewalls resulting in a higher top load and more resistance to denting during distribution and sale of a container. Carbonated beverage processing provides the best example of a method of producing lightweight containers that can withstand the rigors of distribution and bulk pallet stacking due to the raised positive internal pressure in the containers provided by the addition of CO2 during filling prior to capping or sealing. In order to best achieve a high pressure within hot filled containers, and to overcome the negative impact of vacuum build up in the container after a cooling of a filled product, an object of the present invention is to accomplish a higher positive internal pressure within a hot-filled container particularly suited to bulk pallet stacking as part of a processing and conveyor-driven system. There is a requirement to ensure the blow-molder is capable of providing for deeply set mechanically moveable base panels in the container and for an apparatus or a device for forced volume reduction of the container to create an internal pressure that is preferably in excess of ambient pressure at the time of inversion, and a container configuration that can increase further in pressure upon being subjected to increased top-load through bulk pallet stacking for distribution purposes.

[0096] Referring to FIGS. 12A-F, 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 heated and 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."

[0097] 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. In the closed position, shown, the side mold portions 62, 64 define a mold cavity 68 having an extended bottom 6812. The mold cavity 68 corresponds to the shape of a plastic container to be molded therein. The base mold portion 66 is located within the side mold portions 62, 64 and close the extended bottom region 6812 of the mold cavity 68 and is movable with respect to the side mold portions 62, 64 in the vertical direction between the retracted position shown in FIGS. 12A, 12B, 12C, 12D and 12E, and the extended position shown in FIG. 12F. The initial position defines one possible initial configuration of the mold cavity 68 such that an initial length B is defined between the top of the preform 60, which engages the neck finish 38, and the apex 58 of the base mold 66 and by way of example only could measure approximately 208mm in length when the base mold is retracted about 21 mm, or by way of illustrated example 225mm if the base mold is retracted about 30mm. The final position of the base mold 66 accordingly defines the shorter length A, mentioned above relative to the container 10, which corresponds to the length between the top of the preform 60 and the apex 58, measuring by way of the example in FIG.

[0098] 12F only 189mm, wherein the base mold 66 moves outwardly and inwardly about 30mm to provide for an ‘overstretching’ of the central base portion of the container. In this example of the present invention the container may be overstretched along the central length by approximately 10%-20%. As disclosed by Schneider the base mold may move at least 40mm outwardly and inwardly, allowing for a potential overstretching along the central length of approximately 20%. Preferably the container may be overstretched along an axial direction from about 15 mm to 40 mm, more preferably from about 20 mm to about 35 mm, and most preferably from about 20 mm to about 30 mm greater than the axial dimension of the finished container.

[0099] As disclosed further by Kelley (‘388 and ‘944), the base mold may move even further than Schneider and up to at least 65mm between the outward and inward or retracted and extended positions. With reference to FIGS 39A-E a particularly preferred embodiment of the present invention is to incorporate the prior art range of base movement in blow molding and over-stretching the base as Kelley (‘388 and ‘944) discloses. Preferably, the upstanding container bottom sidewall portion or inner wall 32’ has a height H.sub.S as measured parallel to a longitudinal axis A of the container that is preferably within a range of greater than about 0.35 inch to about 1.2 inch - or about 9 mm to about 30mm. The inner wall, 32’ also has a length L.sub.S that is defined as the surface distance between a top portion 28’ and a bottom portion 30’ as viewed in vertical cross-section as shown in FIG. 39D. Preferably, the length L.sub.S is within a range of about 100% to about 115% of the height H.sub.S. The substantially straight portion 26’ is also preferably substantially parallel to a substantially straight portion 27 of an outer sidewall of the container bottom 17, which facilitates the formation of a deep inset invertible base having a relatively tall narrow standing ring. "Substantially parallel" for purposes of this feature is defined as within an angle range of about 0. degree, to about 20. degree.

[0100] Preferably, the substantially smooth inner wall 32 has an average wall thickness T.sub.S that is within a range of about 0.018 inch to about 0.011 inch, and that is most preferably about 0.014 inch.

[0101] As is best shown in FIG. 39E, the base projection portion 42” includes an upstanding sidewall portion 43 that in the preferred embodiment forms the upstanding container bottom sidewall portion 32’ shown in FIGS. 39A and D after the base projection portion 42” is relatively displaced and inverted with respect to the standing ring 40”. Upstanding sidewall portion 43 is preferably although not necessarily substantially smooth and may include a plurality of spaced vertically or longitudinally oriented ribs or grooves that aid in the separation of the base projection portion 42” from the blow mold cavity wall after molding.

[0102] The substantially smooth upstanding sidewall portion 43 preferably has an average wall thickness T.sub.B that is preferably within a range of about 0.018 inch to about 0.011 inch, and that is most preferably about 0.014 inch.

[0103] The substantially smooth upstanding sidewall portion 43 includes a substantially straight portion 45 that in the preferred embodiment is angled downwardly with respect to a vertical plane as viewed in vertical or longitudinal cross-section as shown in FIG.

[0104] 39E. The substantially straight portion 45 is preferably symmetrically shaped about a circumference of the base projection portion 42” so as to define a substantially straight annular wall. The substantially straight portion as viewed in vertical or longitudinal cross-section preferably is substantially parallel to a longitudinal axis A of the container blank 32”. Substantially parallel in this case is defined as being angled with respect to a vertical plane at an angle .THETA.. sub. B that is within a range of about 0. degree, to about 15. degree. The substantially straight portion 45 has a height H.sub.B as measured parallel to a longitudinal axis 44 of the container blank 32” that is preferably greater than about 0.3 inch. The substantially smooth upstanding sidewall portion 43 of the base projection portion 42” has a length L.sub.B measured, as is best shown in FIG. 39E, along its curvature between a first, upper location 48 and a second, lower location 49. Preferably, the length L.sub.B is within a range of about 100% to about 115% of the height H.sub.B. Preferably, the length L.sub.B is also within a range of about 75% to about 115% of the height H.sub.S of the upstanding container bottom sidewall portion of the container blank 32”.

[0105] With reference to FIGS 40 A-E, the range extent of prior art base mold movement or ‘over-stroking’ as disclosed by Kelley (‘388 and ‘944) may be appreciated. FIG 40A shows preferably the upstanding container bottom sidewall portion or inner wall 32’ has a height H.sub.S as measured parallel to a longitudinal axis A of the container that is preferably up to about 1.2 inch - or about 30.4mm.

[0106] As shown in FIG 40B, the overstretching of the base during molding to create an inner wall up to about 30.4mm may be achieved by ensuring the length L.sub.B is preferably overstretched to about 115% of the height H.sub.S, in other words preferably to about 1.35 inches or 34.5mm.

[0107] As best seen in FIGS 40C-E, the prior art method of base over-stroking as disclosed by Kelley (‘388 and ‘944) and incorporated within the present invention provides for a maximum mold base retraction of up to 1.35 inches or 34.5mm, and for a maximum mold base extension of up to 1.2 inches or 30.5mm - meaning a base mold movement during molding within a range of up to 2.55 inches or 65mm. 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.

[0108] FIG. 40F depicts a prior art mold assembly 700 disclosed by Kelley (‘388 and ‘944) that is constructed according to a preferred embodiment of the invention for molding a container blank 32” and then relatively displacing or inverting the base projection portion 42” of the container blank 32” with respect to the standing ring 40 until the base projection portion 42” is positioned above the standing ring 40” in order to complete formation of a container 10.

[0109] Mold assembly 700 includes a first mold portion 72 that is shaped to define an upper portion of the main body of the container blank 32. A second mold portion 74 is shaped to define the rest of the main body, while a third mold portion 76 is shaped to form portions of the container blank 32 bottom including the base projection portion 42”. Actuator 80 is supported by a pedestal 84 that is received within the mold housing 82.

[0110] In order to form a container blank 32, a heated plastic preform is positioned within the mold assembly 700 and the mold assembly is locked. The conventional manufacturing technique consists of inserting the preform blank, previously heated to a temperature above the glass transition temperature of the material (about 80° C. in the case of PET), into a mold provided with a wall defining a cavity with the impression of the container. In the present invention, a preferred temperature range for the preform blank to be pre-heated to is within a range of about 75 degrees C to about 130 degrees C, and more preferably between about 103 - 115 degrees C. The preform is then subjected to a ‘pre-blow’ process in order to prevent the preform from collapsing on itself and is then longitudinally stretched using a stretch rod in otherwise conventional fashion in order to initiate the well-known reheat stretch blow molding process under a low pressure P1.A stretch rod mechanism may be moved into place over the open end of the preform, whereupon telescopic rod member 70 is extended by a suitable mechanism in order to draw preform end against the base portion 66 of the internal cavity blow mold 68, thereby axially stretching the body portion of the preform blank in the manner illustrated in FIG. 12C. Simultaneously therewith or preferably immediately thereafter, a pressurized blowing medium is admitted to the preform through openings in the stretch rod 70 to radially stretch the axially stretched preform outwardly to conform to the inner surface of the cavity walls of mold portions 62 and 63. It is also within the scope of the invention to eliminate rod 70 and achieve stretching solely by means of a pressurized blowing medium especially where relatively small containers are being formed.

[0111] The preform is generally stretched lengthwise first while descending toward the bottom mold portion and while air is blown in at a very low pressure range Pr1 that could start close to ambient pressure and be typically up to about 10 bars (140psi), but is more normally between about 0- 5 bars (0-70psi) up to when the stretch rod is fully extended. Once the preform blank has been fully stretched, if not sooner, the preblow pressure range may be increased to a higher pressure range Pr2 to axially stretch the material in the radial directions and against the mold surfaces more effectively, and the pressure in Pr2 may be increased beyond Pr1 to a higher pre-blowing pressure range reaching about 10 - 15 bars (140psi to 220psi).

[0112] In one preferred embodiment a high pressure range Pr3 is applied at least to finally blow the container shape into good conformity with all mold surfaces, but may be applied earlier to enhance the overstretching of the container prior to movement of the base mold portion 66 to the extended position. Pr3 is initiated starting at the end of the pre-blow pressure range, and typically reaches up to between about 35-40 bars on the order of 520-600 psi. The pressure increase from pre-blow pressure, either Pr1 or Pr2, to the final blow pressure range Pr3 is initiated and may be applied to the interior of the preform with the mold portion 66 in the downward position, or during movement of the mold portion 66 from the downward position to the upward position, or may be applied to the mold portion 66 when already in the upward and extended position, in order to cause the plastic material from the preform to stretch and conform to the mold surfaces that are defined by the various above-described mold portions 72, 74, 76, 66. This forms the container blank 32. After the container blank 32 has been pre-formed, the actuator 80 will then be instructed by a control system to displace the fourth movable mold portion 66 upwardly with respect to the mold portions 72, 74, 76 in order to upwardly displace and invert the base projection portion into its final position above the standing ring of the container. Effectively, movement of the base mold portion 66 is initiated and the base projection portion 42 is inverted in order to form the deep inset base of the container that is depicted in FIG. 1 , 4 or 5. This step is advantageously initiated in cooperation with initiating the increase in pressure to Pr3 to ensure high pressure is applied and maintained within the container blank 32 at least by the time the mold has reached the extended position, in order to hold the final plastic surfaces in position against the mold surfaces to complete heat setting of the material before the pressurized gas is exhausted from the mold assembly.

[0113] Preferably, the level of pressurization within the container blank relative to ambient pressure at the time that the fourth movable mold portion 66 is moved upwardly is at 100% of maximum pressurization or at least 50% of the maximum pressurization that occurs within the mold during the formation of the container blank 32. The pressurization within the container blank relative to ambient pressure at the time that the fourth movable mold portion 66 is preferably at least 260 psi, relative to external ambient pressure. This will prevent crushing of the container sidewalls during the upward movement of the fourth movable mold portion 66. To ensure there is sufficient pressure when the mold portion 66 starts movement therefore, it is a preferred embodiment to initiate the pressure increase from Pr1 or Pr2 (below 260psi) to Pr3 at about the same time as initiating the movement of the base mold from the retracted to the extended position. In this embodiment the pressure will be increasing preferably to at least 260psi and upwards at the same moment the base mold portion 66 begins movement from the retracted position. The time lapse required to reach the upper pressure within Pr3 is approximately the same time as required to move the base mold portion 66 to the extended position, so the timing is most effective to minimize the ‘hold time’ for the final blow and heatsetting of final surfaces as the maximum pressure will be applied at the moment the base mold reaches the final extended position.

[0114] In addition, the upward movement of the movable mold portion 66 is preferably performed before substantial cooling of the base projection portion has occurred, and while the plastic material retains a substantial amount of stretchability and flexibility. Preferably, the upward movement of the movable mold portion 66 takes places within about 10 seconds after the container blank 32 is formed.

[0115] A stretch rod 70 can be inserted into the neck portion of the heated and softened preform 60, and can be used to stretch or elongate the preform 60 substantially along the longitudinal axis of the container. In this manner the unstretched preform 60 is axially stretched to form an over-stretched preform 60’ with a length greater than A and approximately equal to B. As disclosed in Valliencourt the stretch rod 70 may be fully advanced so that it clamps a closed end 600 of the over-stretched preform 60 between an end 714 of the stretch rod 70 and the apex 58 of the base mold 66 while the mold base 66 is either in its initial position or in an intermediate position between the initial and final positions. The need for and timing of the clamping of the preform between the stretch rod 70 and base 66 will vary depending on the exact design characteristics, including weight, of the particular container 10 being molded. The present invention, unlike Valliencourt, anticipates a heated preform being stretched and blown into a mold cavity which is also heated, rather than cooled, in order to provide for far greater stretching ratios. The present invention anticipates stretching the preform at least below the container height and contact surface in order to over-stretch the preform, and unlike Valliencourt, overstretching the container during molding by a ratio of 0-20% or more to achieve greater crystallinity within the base. 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 in what is commonly known in the art of stretch blow molding as a "pre-blow" step. The preblow medium can be initiated during the preform over-stretching step or immediately after the completion of the preform over-stretching step. The exact timing of the introduction of the pre-blow medium will be dependent on the specific design characteristics of the desired container. 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.

[0116] Following a predetermined amount of time for the pre-blowing medium to expand the stretched preform 60 into the partially blown container 28, the base mold 66 may then be moved into its final position. During this movement, the stretch rod 70 is retracted at a rate corresponding to advancement of the base mold 66. This ensures that the end 61 of the over-stretched preform 60 is and remains clamped against the base mold 66, such that the stretch rod 70 is pressing against the inside surface of the preform, and the outside end surface of the preform is pressing against the mold 66. For the avoidance of doubt, this means the gap between the stretch rod 70 and the base mold 66 is filled only with the thickness of the preform polymer. Such clamping prevents shifting or movement of the over-stretched preform 60’ transversely and the formation of an unacceptable container through uneven material expansion caused by a shifting ‘gate’ or end of the preform. The timing delay between the first pre-blowing process and the moving of the base mold 66 is critical to the success of the process and full formation of the container 10. If the delay is too great, too much material may be blown outward and if the base mold 66 is moved too early, an insufficient amount of material will be moved into the chime 82 defining areas of the mold cavity 68.

[0117] As described above, a preferred embodiment of the present invention is to initiate an increase in pressure from a low pressure pre-blow value P1 (either within the ranges described above of Pr1 and / or Pr2) to a higher pressure value P2 at the same time as initiating the movement of the base from the retracted to the deployed or extended or activated position. In this manner the container blank 32 material is still being dynamically stretched under the initial lower pressures in the range Pr3 during the build of pressures to the final higher pressure value P2 at the start of base movement, and during base movement upwards the increase in pressure improves the overstretching dynamics with a more exact final blow timing able to be applied as soon as the base mold reaches full extension.

[0118] In order to stretch blow mold the container from the partially inflated volume, it is commonly known in the art of stretch blow molding to increase the pressure during the final blowing step in order to force the plastic material into complete conformity with the mold cavity 68. This can eliminate the need for the polymer material to expand deeply into tight corners, narrow spaces, for example into the base and chime area, 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. The chime area 82 of the container refers to the bottom edge where the base of the bottle meets the sides. This part is also known as the “heel” of the bottle. It is a crucial area for the stability and strength of the container, especially in lightweight plastic containers required to withstand large top load forces, for example when bulk stacking containers in pallet loads for distribution, as a well-formed chime 82 or heel helps distribute the weight and pressure evenly. Preferably adjacent and above the chime 82 is a bumper region 83 that comprises the lower maximum diameter of the container.

[0119] As a result of retracting the base and applying a pre-blow pressure the polymer can be more easily blown into the base and chime 82 area. After blowing the material into the base and chime 82 area under a low pressure P1 , the next step in the molding process according to a preferred embodiment is to blow the preform 60 into substantial conformity with the mold cavity 68 under a higher pressure P2. This is finally completed preferably after the base mold 66 has been moved into its final position and the mold cavity 68 is in its final molding configuration. However, as described above in a preferred embodiment it may be initiated prior to the base mold 66 actually reaching the final position if sufficient material has been moved into the base and chime 82 area. As stated above, a particularly preferred embodiment is to initiate movement of the base from the retracted to the extended positions at the same time as initiating an increase in pressure from P1 to P2, and in this embodiment the material is not overblown at the time of initiation of the movement of the base mold and completes conformity against the moving mold instead of a stationary mold surface, and completes material heatsetting at high pressure when the mold is in the final extended position. The result of the application of the higher pressure P2 is the sidewalls 22 and base 20 of the fully blown container 10 are fully expanded so that they substantially conform with the side molding surfaces 621 , 641 of the mold halves 62 and 64 and the base mold 66. As used herein, "substantial conformity" means conformity sufficient to produce an acceptable resultant container. During this latter application of blowing medium, the stretch rod 70 continues to clamp a portion, the apex 58, of the blown container 10 between the end 74 of the stretch rod 70 and the apex 58 of the base mold 66. At this point, the fully blown container 10 has a final length A, measured from the rim of the preform 60 to the apex 58 of the base 66. If desired, venting of the blow medium can be accomplished through the stretch rod 70 for added cooling. In summary, while the polymer material is still in a heated and 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).

[0120] It is one object of the present invention to improve upon Valliencourt by overstretching the container during blow molding and by retracting the base a greater distance below the contact surface than provided for in Valliencourt by between at least 15mm and 40mm, as disclosed by Schneider. It is a further object of the present invention to introduce the blowing medium in an improved molding apparatus and including the methods disclosed in Valliencourt in order for at least:

[0121] (a) Providing the blowing medium in at least two different pressures, if not at least three different pressures.

[0122] (b) First providing the blowing medium at a lower pressure and then providing the blowing medium at a higher pressure.

[0123] (c) Providing the blowing medium at one pressure P1 during the phase of stretching the preform, and at another pressure P2 during the pre-blow molding phase with the base in the retracted position, wherein P1 may be the same as P2, or P1 may be less than P2.

[0124] (d) Providing the blowing medium at one pressure P2 during the pre-blow phase of molding, and at another pressure P3 during the final blow molding phase with the base in the final extended position, wherein P2 may be the same as P3, or P2 may be less than P3.

[0125] (e) Providing the blowing medium at one pressure P2 during the pre-blow phase of molding, and at a higher pressure P3 during the final blow molding phase after the base mold has been moved into the final extended position, wherein movement of the base mold from the retracted position to the extended position is completed prior to providing the blowing medium P3.

[0126] (f) First providing the blowing medium at a lower pre-blow pressure P2 before movement of the base mold (66) from the retracted position, and then providing the blowing medium at a higher pressure P3 after movement of the base mold (66) from the retracted position.

[0127] (g) Providing the blowing medium at a lower pre-blow pressure P2 after movement of the base mold (66) from the retracted position, and before the base mold (60) has reached a final extended position, and further providing the blowing medium at a higher pressure P3 prior to the base mold (66) reaching the final extended position, wherein the pressure is increased from P2 - P3 during movement of the base from the retracted position to the extended position. (h) Providing the blowing medium at a lower pre-blow pressure P2 before movement of the base mold (66) from the retracted position, and then providing for an increase in pressure prior to movement of the base mold (66) to the final extended position, wherein the blowing medium is provided at a higher pressure P3 prior to the base mold (66) reaching the final extended position and the pressure is increased from P2 - P3 during movement of the base from the retracted position to the extended position.

[0128] (i) Providing the blowing medium at a lower pre-blow pressure P2 before movement of the base mold (66) from the retracted position to the extended position, and then providing for an increase in pressure simultaneously with movement of the base mold (66) from the retracted position, wherein the blowing medium is provided at a higher pressure P3 prior to the base mold (66) reaching the final extended position and the pressure is increased from P2 - P3 during movement of the base from the retracted position to the extended position.

[0129] (j) Providing the blowing medium at a lower pre-blow pressure P2 before movement of the base mold (66) from the retracted position, and then providing for an increase in pressure after movement of the base mold (66) from the retracted position, wherein the blowing medium is provided at a higher pressure P3 prior to the base mold (66) reaching the final extended position and the pressure is increased from P2 - P3 during movement of the base from the retracted position to the extended position.

[0130] In another preferred embodiment Air can continue to be expelled to blowing pressure into the stretch rod in the blow mold cavity during displacement of the base mold portion 66 to the extended position, or alternatively, the supply of air can be turned off.

[0131] Referring to FIGS. 1-4, by "deeply set" it is meant that the second pressure panel 25 is located entirely between the standing plane P and the upper portion 12 of the container when the pressure panel 25 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.

[0132] 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.

[0133] By utilizing the blow molding method of the present invention, it is possible to initially form the general container shape with an overstretched and partly formed downwardly inclined base panel portion, and then deflect the bottom upwardly at orientation temperature. As a result, the container base having a first pressure panel 23 circumferentially surrounding a deeply-set second pressure panel 25 can be of improved material thickness and uniformity. In addition, the base and pressure panels can be multi-axially stretch oriented to provide increased strength without the attendant thinness or weakness at the heel portion of the bottle.

[0134] 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 degrees 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 degrees F. and can be 325 degrees For 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.

[0135] 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.

[0136] 4,117,062, the entire content of which is incorporated herein by reference, provides further details on this type of post-mold processing.

[0137] Following the blow molding process the container may then be passed directly to a Filling Apparatus for further processing, wherein the processing and handling apparatus includes apparatus for blow molding and filling and capping and cooling and forced volume reduction with container holding devices contained within the volume reduction apparatus, and labelling apparatus; or otherwise transported or conveyed from the blow molder to a filling line apparatus for filling, capping, cooling, forced volume reduction and container stabilization with holding devices, and labelling apparatus. In particular after filling the container with the first pressure panel 23 and the second pressure panel 25 in the base both in first, outward positions and capping or sealing the container, the container may be conveyed to an apparatus or device to mechanically force the second pressure panel 25 in the base upward into a locked position and force an increase in the pressure within the container.

[0138] A forced volume reduction apparatus is now generally described in FIGs 30-36. Filled and capped containers including the invertible pressure panels in the bases of the present invention may be fed into such an apparatus in order to force the central longitudinal height of the container to be reduced in length, in turn forcing the container to reduce in volume, thereby creating an increase in pressure due to the container being sealed. This may be applied to any filled and capped container, irrespective of exact internal temperature at entry, which will vary according to filling or processing technique. The exit pressure from the apparatus will always be greater than the entry pressure.

[0139] Referring firstly to FIGS. 30 and 31 , main turret assembly 530 includes an upper cam assembly 550 and a lower cam assembly 552. Cam assemblies 550 and 552 comprise annular cam plates that encircle shaft 530a and actuator assemblies 534 and 536. The cam plates provide cam surfaces to actuate the actuator and / or device holding assemblies H, as will be more fully described below. Upper cam assembly 550 includes upper cam plate 554 and a lower cam plate 556, which define there between a cam surface or groove 558 for guiding the respective extendable rods 538 of actuator assemblies 534. Similarly, lower cam assembly 552 includes a lower cam plate 560 and an upper cam plate 562 which define there between a cam surface or groove 564 for guiding extendable rods 5116 of actuator assemblies 536. Mounted to extendable rod 538 may be a guide member or cam follower, which engages cam groove or surface 558 of upper cam assembly 550. As noted previously, actuator assemblies 534 are mounted in a radial arrangement on main turret system 530 and, further, are rotatably mounted such that actuator assemblies 534 rotate with shaft 530a and container holder wheel 532. In addition, actuator assemblies 534 may rotate in a manner to be synchronized with the in-feed of containers C. As each of the respective actuator assemblies 534 is rotated about main turret system 530 with a respective container, the cam follower is guided by groove 558 of cam assembly 550, thereby raising and lowering extendable member 538 to enable a holding device to capture and secure the upper end and / or neck finish of each container as seen in FIG 34 in order to stabilize the container prior to mechanically forcing the pressure panel in the base upwards.

[0140] Various container holding devices are may be used, for example the containers according to one preferred embodiment of the invention may be supported at the neck of each container during the forced volume reduction operations to provide maximum control of the container processes. The apparatus may be aligned in a rotary manner as disclosed in the drawings or in a linear direction.

[0141] Referring to FIGS. 32 and 33, one system for singularly activating containers C includes a feed-in scroll assembly 584, which feeds and, further spaces the respective containers at a spacing appropriate for feeding into a feed-in wheel 586. Feed-in wheel 586 is driven by a motor (not shown) which is coupled to a gear or sheave mounted on its shaft and includes a generally star-shaped wheel that feeds-in the containers to turret assembly 588. Turret assembly 588 includes a container holder wheel 590 for guiding and moving containers C and any fixed portion of container holding devices H, for example base plates as similar to base plates common in the art for stabilizing containers in a rotary labelling device (although example base plate holder 5117 suitable for the present invention are configured to include a central opening 5118 for the through passage of an extendable rod or pusher 5116, in a circular path. Containers may be stabilized in many types of holding device H. By way of example only, it is generally most preferable for a holding device to include a lower holding portion for the base region of a container and / or a holding portion for the upper part of the body or bell portion of neck support region of the container. While it is most preferable to include both upper and lower holding devices, it is possible to use only a single upper or lower holding device. By way of example only, a lower holding device may be configured to include a modified base plate holder 5117- as shown more clearly by way of example in FIG 31A-B, wherein a central opening 5118 in the base plate holder provides for the passage of an extendable rod or pusher 5116. Preferably the base plate holder also has sufficient height to the lateral sides 5115 to hold the lower bumper portion in secure position. In other embodiments, the lower holding device may be included or incorporated in conjunction with the housing 5120, which supports extendable rod 5116, in order to provide a vertically mobile holding device that contains the base portion of the container during travel within the volume reduction apparatus, and releases the container for subsequent ejection after base panel 25 inversion, by lowering of the housing 5120 or extendable rod 5116 and attached holding device. In other embodiments the lateral sides may include a portion of the sidewall, and in further embodiments there may be sidewall holding devices either in addition to upper and / or lower holding devices, or in the place of either. By way of example only a holding device for the upper portion of the container may include a neck body gripper 5109 comprising the lowest part of container gripper 5108 and designed to stabilize the region of the container below the seal or cap to prevent sideways movement during inversion of the base. Neck body gripper 5109 may also be configured to enclose or contain any region in the upper part of the container and may also be configured to only contain an upper portion of the container and not the upper neck portion. A plurality of actuator assemblies 5104 and 5106 for removing the containers from the container holders, depending on the style of holding device incorporated, and for activating the respective containers while the containers are stabilized by the holding device, will be more fully described below. After the respective containers have been activated and the respective containers removed from the container holding devices, as the containers are discharged by a discharge wheel 596 to a conveyor 598 for further processing. Wheels 586 and 596 may be driven by a common motor, which is drivingly coupled to gears or sheaves mounted to the respective shafts of wheels 586and 596.

[0142] Turret assembly 588 includes container holder wheel 590, upper and lower cam assemblies 5100 and 5102, respectively, a plurality of actuator assemblies 5104 for gripping the containers, and a plurality of actuator assemblies 5106 for activating the containers. In addition, turret system 588 includes a support plate 5107, which supports the container holders and containers as they are moved by turret system 588. As best seen in FIG. 33, container holder wheel 590, actuator assemblies 5104, actuator assemblies 5106, and plate 5107 are commonly mounted to shaft 588a so that they rotate in unison. Shaft 588a is similarly driven by the common motor, which is drivingly coupled to a gear or sheave mounted on shaft 588a.

[0143] Looking at FIGS. 34-36, actuator assemblies 5104 and 5106 are similarly controlled by upper and lower cam assemblies 5100 and 5102, to remove the containers C from the container holding devices H and activate the respective containers so that the containers are generally subjected to a forced volume reduction and a generally stable configuration wherein the containers can be supported from their bottom surfaces and be conveyed on a conventional conveyor. Referring to FIG.

[0144] 34, each actuator assembly 5104 includes actuator assembly 534 and a container gripper 5108 that is mounted to the extendable rod 538 of actuator assembly 534. As would be understood, grippers 5108 are, therefore, extended or retracted with the extension or retraction of extendable rods 538, which is controlled by upper cam assembly 5100.

[0145] Similar to upper cam assembly 550, upper cam assembly 5100 includes an upper plate 5110 and a lower plate 5112, which define therebetween a cam surface or recess 5114, which guides guide members 572 of actuator assemblies 5104 to thereby extend and retract extendable rods 538 and in turn to extend and retract container grippers 5108. As the containers are conveyed through turret assembly 588, a respective gripper 5108 is lowered onto a respective container by its respective extendable rod 538. Once the gripper is positioned on the respective container, actuator assemblies 5106 are then actuated to extend their respective extendable rods 5116, which extend through plate 5107 and holders H, to apply a compressive force onto the invertible projections of the containers to move the projections to their recessed or retracted positions to thereby activate the containers. As would be understood, the upward force generated by extendable rod 5116 is counteracted by the resistance or opposite downward force of a gripper 5108 on container C. After the activation of each container is complete, the container then can be removed from the holder by its respective gripper 5108 or by way of releasing the containers from the holding devices and transferring the containers back to the conveyor for transfer to the labeller. Additionally and alternatively, a label may be applied as soon as the base has been forced upwardly and could therefore be applied through integration within the forced volume reduction apparatus.

[0146] Referring to FIGS. 34-35, each actuator assembly 5106 is of similar construction to actuator assemblies 534 and 536 and includes a housing 5120, which supports extendable rod 5116. Similar to the extendable rods of actuator assemblies 534 and 536, extendable rod 5116 includes mounted thereto a guide 5122, which engages the cam surface or recess 5124 of lower cam assembly 5102. In this manner, guide member 5122 extends and retracts extendable rod 5116 as it follows cam surface 5124 through turret assembly 588. As noted previously, when extendable rod 5116 is extended, it passes through the base of container holding device H to extend and contact the lower surface of container C and, further, to apply a force sufficient to compress or move the invertible projection its retracted position so that container C can again resume its geometrically stable configuration for normal handling or processing. Importantly, in the present invention the container handling device is configured to provide container stability while inverting the second pressure panel 25, but also allow for the first pressure panel 23 to move outwardly on one radial side or inwardly on the opposite side wherein the standing base radius may alter, and it is important that the handling device provides for such movement of the first pressure panel 23 and alteration in contact surfaces with vertical and transverse or radial stability ensured. To this end, the handling device must provide dynamically for more than one standing base radius during mechanical manipulation of the second pressure panel. The physics of manipulating the activation panel P or extendable rod 5116 is a calculated science recognizing 1) Headspace in a container; 2) Product density in a hot- filled container; 3) Thermal differences from the fill temperature through the cooler temperature through the ambient storage temperature and finally the refrigerated temperature; and 4) Water vapor transmission. By recognizing all of these factors, the size and travel of the activation panel P or extendable rod 5116 is calculated so as to achieve predictable and repeatable results. With the vacuum removed from the hot-filled container, the container can be light-weighted because the need to add weight to resist a vacuum or to build vacuum panels is no longer necessary. Weight reduction of a container can be anticipated to be approximately 20%.

[0147] Referring to FIG 28, after filling and sealing the container according to the present invention, wherein most vacuum is removed through a mechanical volume reduction involving an inversion and locking in place of the second pressure panel 25 in the base, the container is further cooled upon exit of the filling line, generally after being labeled. In accordance with the present invention, and referring to FIG 29, the plastic container 10 is then bulk packed on pallets fairly soon after labeling and there is further cooling of the contents during palletization. Horizontal ribs 602 are designed to achieve optimal performance with regard to vacuum absorption, top load strength and dent resistance. Horizontal ribs 602 are designed to compress slightly in a vertical direction to accommodate for and absorb vacuum forces resulting from hot-filling, capping and cooling of the container contents, and in the present invention to also provide for absorption of any remaining vacuum forces following a mechanical volume reduction and for an increase in pressure. The second pressure panel 25 in the base is configured to resist moving substantially outwardly or downwardly under the increasing internal pressure from the application of the top load, and movement away from the imaginary horizontal plane a-a is only slight as opposed to prior art wherein the base panel may revert more significantly. This leads to a more efficient build up in internal pressure and ensuring a positive pressure is obtained in pallet loads of containers. With reference to FIGS. 26A-C, one example of the above-described horizontal rib 602 may also incorporate the disclosure of Rashid. As depicted in FIG. 26A-B, the plurality of annular ribs 26 are each separated one from another by an annular land 30’. Each annular rib 26, as depicted in FIG. 26B, comprises a pair of opposing outer radii 32, each of which comprises an outer end 34 and an inner end 36’. The outer end 34 of each outer radius 32 is contiguous with an adjacent annular land 30’ and each outer radius 32 extends inward of the annular land 30’.

[0148] Each annular rib 26 further comprises a pair of opposing straight walls 38 each having an outer end 40’ and an inner end 42’. The outer end 40’ of each straight wall 38 is contiguous with an adjacent one of the outer radius inner ends 36’ as depicted in FIG. 26B. Each annular rib 26 further comprises a pair of opposing inner radii 44 each having an outer end 46 and an inner end 48 wherein each straight wall inner end 42’ is contiguous with an adjacent inner radii outer end 46 as depicted in FIG. 26B. Each annular rib 26 further comprises a root wall 50 extending contiguously between the opposing inner radii inner ends 48 to close off the rib 26. Each rib 26 extends annularly about the cylindrical wall 22 and is oriented substantially perpendicular to a central longitudinal axis A of the bottle 10. Furthermore, each land 30’ and each root wall 50 are oriented substantially parallel to the bottle central longitudinal axis A. As disclosed by Rashid it has been found that the strength of the label panel section, or sidewall 22, may be optimized by providing the ribs with an average depth to width ratio in the approximate range of 1.0:1.0-1.1 :1.0. The rib depth C can be measured from the exterior of the land 30’ to the exterior of the root wall 50. The rib width D is measured between the opposing inner radius outer ends 46. Rashid also discloses a “total rib width” being measured between the outer radii outer ends 34 of a single rib 26. In the exemplary example provided by Rashid example measures are provided wherein a rib depth C is measured of 0.120 inches, a rib width D of 0.112 inches, a root wall 50 having a length E of 0.050 inches, the inner radii 44 having a radius of curvature of 0.031 inches and running for ninety degrees (90°), the outer radii 32 having a radius of curvature of 0.060 inches and running for ninety degrees (90°) with the straight wall 38 extending at an angle of fifteen degrees (15°) from perpendicular to the central longitudinal axis A. In this configuration, the depth to width ratio is 1.071:1. The lands 30’ are 0.27 inches long, the total rib width is 0.2475 inches and the ribs 26 have a thickness F of 0.015-0.019 inches. Thus, a total rib width to rib depth ratio that is preferential for Rashid may be calculated of about 2.

[0149] Where Rashid discloses a root wall preferentially having an orientation substantially parallel to the bottle central longitudinal axis A, it is an object of the present invention to include the teachings of Patcheak wherein the root wall may alternatively comprise a radius 500, and for an increase to the depth of the rib and a decrease in the total rib width to rib depth ratio as shown in FIG 26C. It is an object of the present invention to provide a total rib width to rib depth ratio of about 1.6 to about 2, and for the root wall to comprise a radius or to alternatively be substantially parallel to the bottle central longitudinal axis.

[0150] As shown in FIG. 27A-B, one example of the above-described horizontal rib 602 radii, walls, depth and width in combination form a rib angle A. The rib angle A of an unfilled plastic container 10 may be about 58 degrees. After hot-filling, capping and cooling of the container contents, the resultant vacuum forces cause the rib angle A to reduce to about 55 degrees. This represents a reduction of the rib angle A of about 3 degrees as a result of vacuum forces present within the plastic container 10 representing a reduction in the rib angle A of about 5%. Preferably, the rib angle A will be reduced by at least about 3% and no more than about 8% as a result of vacuum forces.

[0151] Horizontal ribs 602 are designed to compress further when the filled container is exposed to increased and / or excessive top load forces. By way of example only, and not intending to be limiting, one or more horizontal circumferential ribs as disclosed in Patcheak may also be included with the base panel configured according to the present invention instead of the more mobile base panel disclosed in Patcheak.

[0152] As shown in FIG. 27A-B, horizontal ribs 602 further include an upper wall 604 and a lower wall 606 separated by an inner curved wall 608. Inner curved wall 608 is in part defined by a relatively sharp innermost radius r.sub.1. In some embodiments, sharp innermost radius r.sub.1 lies within the range of about 0.01 inches to about 0.03 inches. The relatively sharp innermost radius r.sub.1 of inner curved wall 608 facilitates improved material flow during blow molding of the plastic container 10 thus enabling the formation of relatively deep horizontal ribs 602.

[0153] Horizontal ribs 602 each further include an upper outer radius r.sub.2 and a lower outer radius r.sub.3. Preferably both the upper outer radius r.sub.2 and the lower outer radius r3 each lie within the range of about 0.07 inches to about 0.14 inches. The upper outer radius r.sub.2 and the lower outer radius r.sub.3 may be equal to each other or differ from one another. Preferably the sum of the upper outer radius r.sub.2 and the lower outer radius r.sub.3 will be equal to or greater than about 0.14 inches and less than about 0.28 inches.

[0154] As shown in FIG. 27A-B, horizontal ribs 602 further include an upper inner radius r.sub.4 and a lower inner radius r.sub.5. The upper inner radius r.sub.4 and the lower inner radius r.sub.5 each lie within the range of about 0.08 inches to about 0.11 inches. The upper inner radius r.sub.4 and the lower inner radius r.sub.5 may be equal to each other or differ from one another. Preferably the sum of the upper inner radius r.sub.4 and the lower inner radius r.sub.5 will be equal to or greater than about 0.16 inches and less than about 0.22 inches.

[0155] Horizontal ribs 602 have a rib depth RD of about 0.12 inches and a rib width RW of about 0.22 inches as measured from the upper extent of the upper outer radius r.sub.2 and the lower extent of the lower outer radius r.sub.3. As such, horizontal ribs 602 each have a rib width RW to rib depth RD ratio. The rib width RW to rib depth RD ratio is, in some embodiments, in the range of about 1.6 to about 2.0.

[0156] As shown in FIG. 27A-B, the above-described horizontal rib 602 radii, walls, depth and width in combination form a rib angle A. The rib angle A of an unfilled plastic container 10 may be about 58 degrees. After hot-filling, capping and cooling of the container contents, the resultant vacuum forces cause the rib angle A to reduce to about 55 degrees. This represents a reduction of the rib angle A of about 3 degrees as a result of vacuum forces present within the plastic container 10 representing a reduction in the rib angle A of about 5%. Preferably, the rib angle A will be reduced by at least about 3% and no more than about 8% as a result of vacuum forces.

[0157] As stated above, an embodiment of the present invention includes stacking containers atop one another in pallet formation. Pallets are then stacked atop one another resulting in increased top load forces being applied to the plastic container 10 during storage and distribution. Thus, horizontal ribs 602 are designed to further reduce in height and to absorb top load forces. However, horizontal ribs 602 are preferably designed so that the upper wall 604 and the lower wall 606 never come into contact with each other as a result of vacuum or top load forces causing a reduction in height of the container. Instead horizontal ribs 602 are designed to allow the plastic container 10 to reach a state wherein the plastic container 10 is supported in part by the liquid product inside, which is incompressible, and more particularly supported by the gas pressure within the headspace 622 above the liquid when exposed to excessive top load forces thereby preventing permanent distortion of the plastic container 10. This increase in gas pressure may be referred to as a “pneumatic charge up” that results in an increase in resistance within the container to downward or top load forces. In addition, this enables horizontal ribs 602 to rebound and return substantially to the same shape as before the top load forces were applied, once such top load forces are removed. Horizontal lands 610 are generally flat in vertical cross-section as molded. When the plastic container 10 is subjected to vacuum and / or top load forces, horizontal lands 610 are designed to bulge slightly outward in vertical cross-section to aid the plastic container 10 in absorbing these forces in a uniform way.

[0158] In a preferred embodiment of the present invention, the container may even have minimal, or no, significant horizontal ribs contributing to “accommodation” of vacuum or height reduction under top load forces. In this embodiment, the mechanical volume reduction ensures a positive pressure within the container exists prior to entry for bulk pallet stacking. The increased top load forces applied during pallet stacking further increases the pneumatic charge up within the containers, wherein a positive pressure within the vertical load is assured and the requirement for additional ribbing is minimized.

[0159] 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 nonlimiting. 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.

[0160] To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Claims

CLAIMS1. A method of processing a plastic container having a longitudinal axis comprising the steps:blow-molding the container to comprise a first pressure panel circumferentially surrounding a second pressure panel, the first pressure panel comprising a first contact surface in the as-blown container having a first radius and an inner diameter, and a second contact surface having a second radius and an outer diameter, and the second pressure panel being contained radially within and vertically above the first pressure panel;providing the container for hot-filling with a heated liquid, the as-blown container resting on the first contact surface and inner diameter;sealing the hot-filled container, wherein a pressure builds within the headspace of the container and the first pressure panel moves downward and substantially maintains the vertical stability of the container on the first contact surface and further preventing the second pressure panel from moving longitudinally below the first contact surface;cooling the hot-filled container to build a vacuum within the container, wherein the first pressure panel moves upwardly under increasing vacuum force from the cooling of the liquid contents and moves the second pressure panel longitudinally upward with it, wherein the container rests on the second contact surface and outer diameter improving the vertical stability of the container, wherein the second radius is greater than the first radius and the second diameter is greater than the first diameter;conveying the cooled container to an inverter device for forced volume reduction of the container;securing the container within a holding device;applying a mechanical force longitudinally against the second pressure panel to move and invert the second pressure panel upwardly and inwardly into the container to reduce the volume of the container and increase the pressurewithin the container, wherein the first pressure panel simultaneously moves back outwardly or downwardly; and,conveying the sealed hot-filled and cooled container and arranging for bulk packing with multiple other containers on pallets wherein a top load force is applied to the container that creates a positive pressure within a distribution load of containers.

2. The method of claim 1 , wherein the outer diameter is less than about 100% and the inner diameter is greater than about 60% of the maximum container diameter.

3. The method of claim 1 , wherein the step of moving or inverting the second pressure panel causes the first pressure panel to rest again substantially on the first contact surface and inner diameter and a positive pressure exists within the container.

4. The method of claim 4, wherein a vacuum exists within the container following further cooling of the container and prior to loading in to bulk pallet loads.

5. The method of claim 5, wherein a positive pressure exists within the distribution load of containers after the top-load force is applied.

6. The method of claim 1 wherein the first pressure panel comprises a plurality of footed portions or contact elements.

7. The method of claim 6 wherein the first pressure panel comprises greater than 10 footed portions or contact elements.

8. The method of claim 7 wherein the first pressure panel comprises greater than 18 footed portions or contact elements.

9. A method of processing a hot-filled plastic container having a longitudinal axis and improved vertical stability during processing, the container comprising:a neck finish;a sidewall portion extending from the neck finish;a base portion extending from the sidewall portion having a first as-blown contact surface for supporting the container for filling, the base portion including a first pressure panel circumferentially surrounding a second pressure panel, wherein the first pressure panel provides a first as-blown contact surface on an inner diameter and the second pressure panel is configured to have an inner annular wall having a steep downwardly inclined portion relative to the longitudinal axis and a central push-up portion configured to engage with a mechanical device and be moveable upwardly under a mechanical force after the container is filled with a liquid and sealed;the method comprising:blow-molding the plastic container in a mold apparatus having a mold cavity, wherein the mold cavity comprises a first side mold portion and a second side mold portion closed around a preform, the preform comprising a heated and softened polymer material, wherein the blowmolding comprises the steps:inserting the preform into the mold cavity and closing the side molds around the preform, wherein the mold cavity includes an open or elongated bottom portion during inflation of the preform and the side mold portions are closed, and a base mold portion is in a retracted position;inserting into a neck portion of the preform a stretch rod; elongating the preform through insertion of the stretch rod from a retracted position to an extended position and clamping the closed end of the preform between the stretch rod and the retracted base mold;providing air or another blowing medium under a lower pressure P1 and at least partially inflating the preform into conformity with the mold cavity under a pre-blow step, wherein the length of the container is overstretched below the contact surface;providing the blowing medium under a higher pressure P2 and inflating the preform into substantially complete conformity with the mold cavity under an increased pressure;moving the base mold portion from the retracted position to an extended position; and,reducing or removing the blowing medium pressure and releasing the formed container from the mold cavity by retracting the base mold portion and separating the side mold portions; providing the blow-molded plastic container for hot-filling by transferring, conveying or transporting the container after blow-molding to a filling line apparatus;hot-filling the plastic container with the first pressure panel in a first position, wherein the container rests on the first contact surface having the inner diameter defined by the first radius;sealing or capping the hot-filled plastic container with the first pressure panel and the second pressure panel in downwardly inclined positions;conveying the sealed hot-filled container for further processing, wherein the first contact surface of the container is in direct contact with the conveyor and the container is supported by the inner diameter and is vertically stable, and the downwardly inclined portion and the push-up portion are in a first position;providing the sealed hot-filled plastic container for cooling by transferring, conveying or transporting the container through a cooling device or apparatus, wherein the internal pressure within the container reduces and the first pressure panel moves upwardly such that thecontainer rests on the second contact surface and outer diameter and has greater vertical stability while under vacuum; and,providing the sealed hot-filled plastic container for a forced volume reduction by transferring, conveying or transporting the container in a rotary or linear direction, said providing comprising the steps of:positioning the container within an in-feed apparatus configured to create space between adjacent multiple filled and sealed containers;transferring the container to a position within a volume reduction apparatus wherein the container is stabilized by a holding device in at least an upper position or a lower position; placing the container longitudinally above a mechanical rod, pusher or punch-like device driven by an actuator apparatus;engaging in a retracted position a surface of the mechanical rod, pusher or punch-like device against a contact surface on the underside of the push-up portion and above the contact surface of the container;activating the actuator apparatus and moving the mechanical rod, pusher or punch-like device to an extended position, wherein the downwardly inclined portion and the pushup portion of the hot-filled and sealed plastic container are forced from the first position to a second position; wherein the push-up portion is positioned longitudinally away from the finish in the first position, and longitudinally toward the finish in the second position and the internal volume of the sealed hot filled container is reduced and the pressure is increased, and further wherein the first pressure panel moves downwardly or outwardly wherein the container rests on the first contact surface again having the inner diameter defined by the first radius; and,conveying the sealed hot-filled container and arranging for bulk packing with multiple other containers on pallets and applying a top load to force a further volume and height reduction and further increase in pressure within the container, wherein the pressure is a positive pressure and wherein the container rests again on the second contact surface having the outer diameter defined by the second radius.

10. The container of claim 9, wherein a top load force is applied to multiple pallets during storage, transportation and distribution.

11. The method of claim 10, wherein the container comprises multiple horizontal ribs in the sidewall designed to compress in height under the applied top load force and cause an increase in internal pressure, the increase in internal pressure reducing any remaining vacuum pressure and / or providing for an increased positive internal pressure, the increased pressure providing for the container to reach a state wherein the container is supported in part by the product inside.

12. The method of claim 11 , wherein the container has an internal vacuum pressure prior to the bulk packing.

13. The method of claim 11 , wherein the container has a positive pressure prior to the bulk packing and an increased positive pressure during the bulk packing.

14. The method of claim 9, wherein the step of moving the base mold portion from the retracted position to an extended position begins under the pre-blow pressure P1 and before a step of increasing the blowing medium from P1 to P2 begins.

15. The method of claim 9, wherein the base mold portion is moved in an upward vertical direction during the step of increasing the blowing medium from P1 to P2.

Images