Container having meta-stable panels

Abstract

A container has meta-stable panels to compensate for internal vacuum from hot filling. The panels include a groove that yields during deformation such that the stiffness of the panel varies from its pre-yield stage to its post-yield stage.

1 . A plastic bottle suitable for hot-filling, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least one volume compensation panel that generally deflects inwardly in response to negative pressure after hot filling, wherein during a pre-yielding stage, the vacuum panel deflects inwardly at a first stiffness and, during a post-yielding stage, the vacuum panel deflects inwardly at a second stiffness   
     
     
         2 . The bottle of  claim 1  wherein a portion of the panel yields during the inward deflection, thereby facilitating a change in stiffness. 
     
     
         3 . The bottle of  claim 2  wherein the first stiffness does not equal the second stiffness. 
     
     
         4 . The bottle of  claim 1  wherein the yielding stage includes buckling. 
     
     
         5 . The bottle of  claim 1  wherein each one of the vacuum panels includes a groove disposed between a pair of fields. 
     
     
         6 . The bottle of  claim 5  wherein a portion of the groove slowly gives way during said inward deflection, thereby facilitating the stiffness variation. 
     
     
         7 . The bottle of  claim 5  wherein a portion of the groove buckles during said inward deflection, thereby facilitating the stiffness variation. 
     
     
         8 . The bottle of  claim 7  wherein each one of the vacuum panels further includes:
 a pair of opposing rim walls, each one of the rim walls is disposed proximate a corresponding edge of the body sidewall,   a pair of raised fields disposed within said edge, and   a groove disposed between the fields.   
     
     
         9 . The bottle of  claim 8  wherein a bottom of the groove is higher than a bottom of the rim walls, and each one of an uppermost portion of the fields is higher than the bottom of the groove. 
     
     
         10 . The bottle of  claim 9  wherein the grove has a pair of opposing end walls that extend inwardly from the groove bottom to the rim walls. 
     
     
         11 . The bottle of  claim 9  wherein the end walls buckle in response to the negative pressure. 
     
     
         12 . The bottle of  claim 11  wherein said buckling enables inward movement of the groove. 
     
     
         13 . The bottle of  claim 1  wherein the groove extends approximately from one of the rim walls approximately to the opposing rim. 
     
     
         14 . The bottle of  claim 1  wherein the body further includes one or more vacuum panels. 
     
     
         15 . A plastic bottle suitable for hot-filling, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least two volume compensation panels that deflect inwardly after hot-filling, each one of the panels including an upper field, a lower field, and a rib that is disposed between the upper and lower fields and that includes an oblique portion that buckles during the volume compensation process, said buckling facilitating inward movement of the upper and lower fields changes the stiffness from a pre-buckling value to a post-buckling value.   
     
     
         16 . The bottle of  claim 15  wherein the oblique portion of the rib is located at an end of a bottom of the rib. 
     
     
         17 . The bottle of  claim 16  wherein the oblique portion forms an oblique angle with a bottom of the rib and is not tangential to the body sidewall. 
     
     
         18 . The bottle of  claim 16  wherein the rib has sidewalls that extend upwardly from the rib bottom and connect to the fields. 
     
     
         19 . The bottle of  claim 18  wherein the fields have an approximately flat surface. 
     
     
         20 . A method of absorbing negative pressure within a hot-filled plastic bottle, the method comprising the steps of:
 (a) providing a bottle having:
 an enclosed circular base; 
 an upper portion including an opening; and 
 a body disposed between the base and the upper portion, the body includes a sidewall and at least two volume compensation panels, 
   (b) filling the bottle with a (liquid) product at an elevated temperature and sealing (capping) the opening; and   (c) at least a portion of the panels deflecting inwardly after the filling and sealing step (b) in response to negative pressure within the bottle, said inward deflection includes a first main stage wherein the volume compensation panels exhibit a first stiffness and a second main stage wherein the volume compensation panels exhibit a second stiffness.   
     
     
         21 . The method of  claim 20  wherein providing step (a) includes providing a bottle in which each of the vacuum panels includes a rib disposed between opposing fields. 
     
     
         22 . The method of  claim 21  wherein the rib undergoes a change in shape between the first and second main stages of the deflecting step (c). 
     
     
         23 . The method of  claim 21  wherein the rib undergoes buckles between the first and second main stages of the deflecting step. 
     
     
         24 . The method of  claim 19  wherein each one of the vacuum panels includes a groove disposed between a pair of fields. 
     
     
         25 . The method of  claim 24  wherein a portion of the groove buckles during said inward deflection, thereby facilitating the transition form the first stiffness to the second stiffness. 
     
     
         26 . The method of  claim 25  wherein each one of the vacuum panels further includes:
 a pair of opposing rim walls, each one of the rim walls is disposed proximate a corresponding edge of the body sidewall,   a pair of raised fields disposed within said edge, and   a groove disposed between the fields.   
     
     
         27 . The method of  claim 26  wherein a bottom of the groove is higher than a bottom of the rim walls, and each one of an uppermost portion of the fields is higher than the bottom of the groove. 
     
     
         28 . The method of  claim 27  wherein the grove has a pair of opposing end walls that extend inwardly from the groove bottom to the rim walls. 
     
     
         29 . The method of  claim 27  wherein the end walls buckle in response to the negative pressure. 
     
     
         30 . The method of  claim 29  wherein said buckling enables inward movement of the groove. 
     
     
         31 . A plastic bottle suitable for a hot-filling process in which internal vacuum is created, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least one volume compensation panel that generally deflects inwardly in response to vacuum after hot filling, the panel having an upper field, a lower field, and a hinge located between the upper and lower fields,   wherein deformation of the panel in response to vacuum occurs in a first stage, a transition stage after the first stage, and a second stage after the transition stage; such that:
 (i) in the first stage the upper field and lower field are gradually drawn inwardly in response to vacuum; 
 (ii) the transition stage is unstable such that at least a portion of the panel jumps from the first yielding stage to the second yielding stage; and 
 (iii) in the second yielding stage the upper field and lower field are gradually drawn inwardly in response to vacuum. 
   
     
     
         32 . The bottle of  claim 1  wherein each of the upper field and the lower field have an inner end located proximate the hinge and an outer end located distal from the hinge, and the inward deformation of each field inner end is greater than the deformation of the each field outer end. 
     
     
         33 . The bottle of  claim 32  wherein the inward deformation of each field inner end is greater than the deformation of the each field at its longitudinal center. 
     
     
         34 . The bottle of  claim 32  wherein, in longitudinal cross section, a line between the upper field outer end and the upper field inner end forms an internal angle with a line between the lower filed outer end and the upper field inner end, and the angle is less than 180 degrees. 
     
     
         35 . The bottle of  claim 34  wherein the angle goes to approximately 180 degrees after vacuum deformation is complete. 
     
     
         36 . The bottle of  claim 34  wherein the angle goes to greater than 180 degrees after vacuum deformation is complete. 
     
     
         37 . The bottle of  claim 32  wherein the inner end of the upper field is located at the lowermost end of the upper field, and the inner end of lower field is located at the uppermost end of the lower field. 
     
     
         38 . The bottle of  claim 32  wherein the hinge is formed by an approximately horizontal groove. 
     
     
         39 . The bottle of  claim 32  wherein each one of the upper field and the lower field forms an approximately straight line in longitudinal cross section through the center of the panel. 
     
     
         40 . The bottle of  claim 32  wherein each field has a lobe-like shape. 
     
     
         41 . A plastic bottle suitable for a hot-filling process in which internal vacuum is created, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least one volume compensation panel that generally deflects inwardly in response to vacuum after hot filling, the panel having an upper field, a lower field, and an approximately horizontal groove between the upper field and lower field,   wherein deformation of the panel in response to vacuum occurs in a first stage, a transition stage after the first stage, and a second stage after the transition stage; such that:
 (i) in the first stage the upper field and lower field are gradually drawn inwardly in response to vacuum; 
 (ii) the transition stage in which at least a portion of the panel jumps from the first yielding stage to the second yielding stage; and 
 (iii) in the second yielding stage the upper field and lower field are gradually drawn inwardly in response to vacuum. 
   
     
     
         42 . The bottle of  claim 41  wherein each one of the upper field and the lower field merge into the groove. 
     
     
         43 . The bottle of  claim 41  wherein, in longitudinal cross section, the groove has a curved lower wall and a pair of opposing walls. 
     
     
         44 . A plastic bottle suitable for a hot-filling process in which internal vacuum is created, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least one volume compensation panel that generally deflects inwardly in response to vacuum after hot filling, the panel having an upper field, a lower field, and an interruption separating the upper field from the lower field; each one of the upper field and the lower field forming a peak before the bottle is deformed by the vacuum, the lower field peak is located opposite the upper field peak relative to the interruption;   wherein deformation of the panel in response to vacuum occurs in a first stage, a transition stage after the first stage, and a second stage after the transition stage; such that:
 (i) in the first stage the upper field and lower field are gradually drawn inwardly in response to vacuum; 
 (ii) the transition stage in which at least a portion of the panel jumps from the first yielding stage to the second yielding stage; and 
 (iii) in the second yielding stage the upper field and lower field are gradually drawn inwardly in response to vacuum, and 
   wherein radial height, relative to other portions of the fields, of each of the peaks is reduced upon vacuum deformation.   
     
     
         45 . A plastic bottle suitable for a hot-filling process in which internal vacuum is created, said bottle comprising:
 an enclosed circular base;   an upper portion including an opening; and   a body disposed between the base and the upper portion, the body includes a sidewall and at least one volume compensation panel including:
 an upper field that, in longitudinal cross section, has a radial peak; 
 a lower field that, in longitudinal cross section, has a radial peak; 
 an approximately horizontal groove, located between the upper field and the lower field, that separates the upper field peak from the lower field peak; 
   wherein radial height, relative to other portions of the fields, of each of the peaks is reduced upon vacuum deformation.   
     
     
         46 . The bottle of  claim 45  wherein includes a groove extending around the panel and merging with the sidewall. 
     
     
         47 . The bottle of  claim 46  wherein the peaks are distal to the upper and lower edges of the panel. 
     
     
         48 . The bottle of  claim 47  wherein each one of the fields has a width proximate its peak that is smaller than a width proximate the upper and lower edges of the field, whereby the panels and groove form an hourglass shape. 
     
     
         49 . The bottle of  claim 48  wherein the upper field has a width that gradually narrows from its upper edge to its peak and the lower field has a width gradually narrows from its lower edge to its peak 
     
     
         50 . The bottle of  claim 49  wherein includes a groove extending around the panel and merging with the sidewall. 
     
     
         51 . The bottle of  claim 50  wherein a pair of opposing inclined walls extend from the groove along side edges of the panel generally radially outwardly to side edges of the fields and to the groove.