US Patent 7581654 Round hour-glass hot-fillable bottle

A blow-molded container has a body portion extending upward from a base. A shoulder portion extends upward and axially inward above an upper margin of the side wall to a finish defining an opening adapted to accept a closure. Horizontal linear segments are joined end to end to define a waist of polygonal cross-section. Each linear segment joins a pair of vertically diverging surfaces, the surfaces having lateral edges. A protruding panel is situated between the lateral edges of each horizontally adjacent pair of diverging surfaces. The panel includes a dimple that can act as a deflection initiation point, with any vacuum induced deflection progressively expanding laterally and axially in response to increasing vacuum within the container.