Method Of Processing A Plastic Container Including A Multi-Functional Base

Abstract

A container can have a body with an integrally formed base attached to the body. The base includes a concave annular wall extending from the container sidewall to a standing surface, and an inner wall extending from the standing surface to a substantially flat inner annular wall. The inner annular wall is recessed in the base and is substantially perpendicular to the container sidewall. The inner annular wall includes a centrally located dimple. The dimple includes a plurality of spaced apart and radially extending indented ribs. One or more of the ribs extend radially into a brace that tapers to meet the inner annular wall.

What is claimed is: 
     
         1 . A method comprising:
 providing a container comprising a body having an integrally formed base attached thereto, said base including:
 a concave annular wall extending from a sidewall of the container to a standing surface; 
 an inner wall extending from the standing surface to a substantially flat inner annular wall that is substantially perpendicular to the sidewall; and 
 a dimple centrally located within said inner annular wall and comprising a plurality of spaced apart radially extending indented ribs, each of said ribs comprising a brace extending radially from said dimple and tapering toward said inner annular wall, the tapering braces each including a wide portion and a narrow portion narrower than the wide portion, the wide portion being arranged at a junction with the inner annular wall, 
 wherein said inner annular wall of said base has a position to which it flexes upwardly and has another position to which it flexes downwardly in response to variations in pressures within the container, when filled and sealed, without undergoing unwanted permanent deformation; 
   filling the container;   sealing the container; and   upwardly and downwardly flexing the inner annular wall of the filled container above a standing ring, the flexing being in response to variations in pressures within the container, when filled and sealed.   
     
     
         2 . A method of processing a plastic container, comprising:
 (a) providing a plastic container having an upper portion including a finish, a sidewall, a lower portion including a base defining a standing surface, and a substantially transversely-oriented pressure panel located in the base;   (b) introducing heated liquid contents into the plastic container with the pressure panel located in an outwardly-inclined position entirely between the standing surface and the upper portion;   (c) capping the plastic container; and   (d) moving the pressure panel to an inwardly-inclined position entirely between the standing surface and the upper portion.   
     
     
         3 . The method of  claim 2 , further comprising the step of moving the pressure panel from the inwardly-inclined position to the outwardly-inclined position prior to the step (b). 
     
     
         4 . The method of  claim 3 , further comprising the step of blow molding the plastic container with the pressure panel in the inwardly-inclined position. 
     
     
         5 . The method of  claim 2 , further comprising the step of applying mechanical force to the pressure panel to move the pressure panel from the outwardly-inclined position to the inwardly-inclined position. 
     
     
         6 . The method of  claim 2 , further comprising the step of cooling the plastic container and liquid contents prior to the step (d). 
     
     
         7 . The method of  claim 2 , wherein the step (d) occurs as a result of internal vacuum formed within the plastic container due to shrinkage of the liquid contents. 
     
     
         8 . A method of blow molding a plastic container, comprising:
 (a) enclosing a 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; and   (c) displacing the base mold portion with respect to the first and second side mold portions to form a transverse pressure panel deeply set within a base portion of the plastic container.   
     
     
         9 . The method of  claim 8 , further comprising the step of opening the blow mold to release the plastic container. 
     
     
         10 . The method of  claim 8 , wherein the step (a) comprises enclosing a container preform within the blow mold. 
     
     
         11 . The method of  claim 10 , further comprising the step of stretching the container preform with a stretch rod. 
     
     
         12 . The method of  claim 8 , wherein the base portion comprises a standing surface defining a standing plane, and the pressure panel is located between the standing plane and an upper portion of the plastic container. 
     
     
         13 . The method of  claim 8 , wherein the mold cavity defines a longitudinal axis of the plastic container, and the step (c) comprises displacing the base mold portion substantially along the longitudinal axis. 
     
     
         14 . The method of  claim 8 , further comprising the step of substantially completely conforming the polymer material to the mold cavity prior to the step (c). 
     
     
         15 . A method of processing a bottle, comprising:
 blowing the bottle in an as-blown position;   filling the bottle with a hot liquid;   moving a pressure panel down from the as-blown position;   capping and sealing the filled bottle filled with the hot liquid;   creating a vacuum force in the filled bottle by cooling the hot liquid;   in response to the vacuum force, the pressure panel moving up into the interior of the bottle, the moving up causing a reduction in the vacuum force.