US Patent 9296539 Variable displacement container base

Base includes an outer support wall, a support surface extending inwardly from the outer support wall and defining a reference plane, an inner support wall extending upwardly from the support surface, a first radiused portion extending radially inward from the inner support wall and concave relative to the reference plane, a second radiused portion extending radially inward from the first radiused portion and convex relative to the reference plane, an intermediate surface extending radially inward from the second radiused portion and substantially parallel to the reference plane, a third radiused portion extending radially inward from the intermediate surface and convex relative to the reference plane, and a central portion disposed proximate the third radiused portion.