Plastic bottle with superior top load strength

Abstract

A plastic bottle has a champagne base that includes a planar standing ring located between a lower margin of a convex heel of the base and a lowermost portion of a central concavity within the standing ring. By making the inside vertical radius of the convex heel lower margin and central concavity lowermost portion sufficiently small, the bottle is shown to exhibit increased top load strength without any increase in plastic. The bottle also has a larger standing ring diameter leading to a more stable bottle.

1 . A plastic bottle having a sidewall and a bottom structure closing the bottle at a lower end portion of the sidewall and providing superior resistance to failure when the bottle is subjected to a vertical load, the bottom having an outside surface rotationally symmetric about a longitudinal axis of the bottle, the bottom outside surface comprising: a convex heel having an upper margin of diameter D integrally formed with the lower end portion of the sidewall, a lower margin of the convex heel leading to a continuous planar standing ring lying in a plane perpendicular to the longitudinal axis of the bottle to support the bottle on any underlying surface, and a central concavity inside the standing ring, the central concavity including a first surface defined by a circular cone inclined with respect to the plane of the standing ring, the first surface having a lower most portion smoothly joining the standing ring, wherein the lower margin of the convex heel has an inside vertical radius of less than 0.11D, and the lowermost portion of the first surface having an inside vertical radius of less than 0.10D to achieve enhance failure resistance and stability. 
     
     
         2 . The plastic bottle of  claim 1 , wherein a portion of the convex heel above the lower margin of the convex heel has a vertical inside radius of curvature of between 1.42D and 1.26D. 
     
     
         3 . The plastic bottle of  claim 1 , wherein the planar standing ring has a width of between 0.015D and 0.02D. 
     
     
         4 . The plastic bottle of  claim 1 , wherein the planar standing ring has an inner diameter of between 0.818D and 0.73D. 
     
     
         5 . The plastic bottle of  claim 1 , wherein a portion of the inside concavity first surface above the lowermost portion of the first surface is inclined at an angle of between 35° and 40° with respect to a plane formed by the standing ring. 
     
     
         6 . The plastic bottle of  claim 1 , wherein the lowermost portion of the inside concavity first surface has an inside vertical radius of between 0.055D and 0.084D. 
     
     
         7 . The plastic bottle of  claim 1 , wherein the lower margin of the convex heel leading to a planar standing ring has an inside vertical radius of between 0.039D and 0.067D. 
     
     
         8 . The plastic bottle of  claim 1 , wherein the central concavity further comprises a second surface joined to an upper margin of the first surface by a concave ring, the second surface being a downwardly convex dome centered on the longitudinal axis of the bottle. 
     
     
         9 . The plastic bottle of  claim 8 , wherein the inside concavity second surface has a radius of curvature of between 0.23D and 0.27D. 
     
     
         10 . The plastic bottle of  claim 8 , wherein the inside concavity second surface has a lowermost nadir situated between 0.15D and 0.19D above the standing ring. 
     
     
         11 . The plastic bottle of  claim 8 , wherein the concave ring joining the inside concavity first surface to the inside concavity second surface has an outside vertical radius of between 0.059D and 0.066D. 
     
     
         12 . A plastic bottle having a sidewall and a bottom structure closing the bottle at a lower end portion of the sidewall and providing superior resistance to failure when the bottle is subjected to a vertical load, the bottom having an outside surface rotationally symmetric about a longitudinal axis of the bottle, the bottom outside surface comprising: a convex heel having an upper margin of diameter D integrally formed with the lower end portion of the sidewall, a lower margin of the convex heel leading to a continuous planar standing ring lying in a plane perpendicular to the longitudinal axis of the bottle to support the bottle on any underlying surface, and a central concavity inside the standing ring, the central concavity including a first surface defined by a circular cone inclined with respect to the plane of the standing ring, the first surface having a lower most portion smoothly joining the standing ring, wherein the lower margin of the convex heel has an inside vertical radius of less than 0.11D, and the lowermost portion of the first surface having an inside vertical radius of less than 0.10D to achieve a standing ring diameter of at least 0.74D. 
     
     
         13 . The plastic bottle of  claim 12 , wherein the lower margin of the convex heel leading to a planar standing ring has an inside vertical radius of between 0.039D and 0.067D. 
     
     
         14 . The plastic bottle of  claim 13 , wherein the lowermost portion of the inside concavity first surface has an inside vertical radius of between 0.055D and 0.084D. 
     
     
         15 . The plastic bottle of  claim 14 , wherein a portion of the convex heel above the lower margin of the convex heel has a vertical inside radius of curvature of between 1.42D and 1.26D. 
     
     
         16 . The plastic bottle of  claim 15 , wherein the central concavity further comprises a second surface joined to an upper margin of the first surface by a concave ring, the second surface being a downwardly convex dome centered on the longitudinal axis of the bottle. 
     
     
         17 . The plastic bottle of  claim 16 , wherein the inside concavity second surface has a radius of curvature of between 0.23D and 0.27D. 
     
     
         18 . The plastic bottle of  claim 16 , wherein the inside concavity second surface has a lowermost nadir situated between 0.15D and 0.19D above the standing ring. 
     
     
         19 . The plastic bottle of  claim 16 , wherein the concave ring joining the inside concavity first surface to the inside concavity second surface has an outside vertical radius of between 0.059D and 0.066D. 
     
     
         20 . A plastic bottle having a sidewall and a bottom structure closing the bottle at a lower end portion of the sidewall and providing superior resistance to failure when the bottle is subjected to a vertical load, the bottom having an outside surface rotationally symmetric about a longitudinal axis of the bottle, the bottom outside surface comprising: a convex heel having an upper margin of diameter D integrally formed with the lower end portion of the sidewall, a lower margin of the convex heel leading to a continuous planar standing ring lying in a plane perpendicular to the longitudinal axis of the bottle to support the bottle on any underlying surface, and a central concavity inside the standing ring, the central concavity including a first surface defined by a circular cone inclined with respect to the plane of the standing ring, a second surface joined to an upper margin of the first surface by a concave ring, the second surface being a downwardly convex dome centered on the longitudinal axis of the bottle, the first surface having a lower most portion smoothly joining the standing ring, wherein the lower margin of the convex heel has an inside vertical radius of between 0.039D and 0.067D, and the lowermost portion of the first surface having an inside vertical radius of between 0.055D and 0.084D to achieve a standing ring diameter of at least 0.74D.