Plastic container with champagne style base

Abstract

A champagne type base for a molded polymeric container has an annular step immediately inside an annular contact ring. A push-up area is a central portion of the base immediately surrounding the container longitudinal axis. A transition region between the push-up area and the annular step provides for outstanding base stabilization. The transition region includes an upwardly arching surface extending between the annular step and the push-up area with a plurality of integrally molded, spaced apart, radially extending and downwardly projecting hollow ribs. Each of the ribs has a lower curved surface extending substantially continuously from the push-up area to the inner margin of the annular step.

1 . A molded polymeric container, including a body portion having a longitudinal axis, a sidewall and a champagne type base portion that is molded integrally with said sidewall, said champagne type base portion comprising: 
 a lower end that defines an annular contact ring for supporting the container with respect to an underlying surface;    an annular step situated immediately radially inward of the annular contact ring, the annular step having a substantially vertical outer wall and a substantially horizontal inner wall, the inner wall having an inner margin;    a push-up area immediately surrounding the longitudinal axis; and    a transition region interposed between the push-up area and the annular step, the transition region including an upwardly arching surface extending between the push-up area and the annular step, and a plurality of integrally molded, spaced apart, radially extending, and downwardly projecting ribs, each rib having a lower curved surface extending substantially continuously from the push-up area to the annular step.    
   
   
       2 . The molded polymeric container of  claim 1  wherein the upwardly arching surface has a radius of curvature R S , the rib lower curved surface has a radius of curvature R R , and R S >R R .  
   
   
       3 . The molded polymeric container of  claim 2  wherein:  
       2.0 R R >R S >1.5 R R .  
   
   
       4 . The molded polymeric container of  claim 3  wherein R S  1.7 R R .  
   
   
       5 . The molded polymeric container of any of claims  1 ,  2 ,  3  or  4  wherein the maximum height to base width ratio of each rib is less than 1.  
   
   
       6 . The molded polymeric container of  claim 5  wherein the maximum height to base width ratio of each rib is about 0.7.  
   
   
       7 . The molded polymeric container of  claim 5  wherein each rib includes two sides leading from the lower curved surface to the adjacent upwardly arching surface, the two sides of each rib diverging from each other.  
   
   
       8 . The molded polymeric container of  claim 7  wherein the angle of divergence of the two sides of each rib from each other is between about 25° and 35°.  
   
   
       9 . The molded polymeric container of  claim 5  wherein the annular contact ring is horizontally planar and has a width of about 0.15 R.  
   
   
       10 . The molded polymeric container of  claim 5  further comprising a convex heel portion joining an outer margin of the annular contact ring, the heel portion having a vertical radius of curvature of about 0.5 R.  
   
   
       11 . A molded polymeric container, including a body portion having a longitudinal axis, a sidewall and a champagne type base portion that is molded integrally with said sidewall, said champagne type base portion comprising: 
 a lower end that defines a horizontally planar annular contact ring for supporting the container with respect to an underlying surface;    an annular step situated immediately radially inward of the annular contact ring, the annular step having a substantially vertical outer wall and a substantially horizontal inner wall, the inner wall having an inner margin;    a push-up area immediately surrounding the longitudinal axis; and    a transition region interposed between the push-up area and the annular step, the transition region being substantially devoid of any extreme angles and tapers, the transition region including an upwardly arching surface extending between the push-up area and the annular step, and a plurality of integrally molded, spaced apart, radially extending, and downwardly projecting ribs, each rib having a lower curved surface extending substantially continuously from the push-up area to the annular step.