Flex surface for hot-fillable bottle

A blow-molded bottle comprising a base, a side wall having a lower margin joining the base, the side wall extending upward from the base to an upper margin, an inwardly indented ring joining the upper margin of the side wall to a shoulder portion, the shoulder portion extending upward above the inwardly indented ring and inward to a neck surrounding a vertical axis below a finish defining a opening adapted to accept a closure, the shoulder including a circumferentially continuous outwardly extending upper peripheral margin adjoining the neck, an outwardly protruding ring immediately above the inwardly indented ring, and a flexible concave perimeter surface joining the upper peripheral margin to the outwardly protruding ring, the entire flexible concave perimeter surface being at a radius measured from the vertical axis that is greater than the outwardly extending upper peripheral margin, the vertical midpoint of the flexible concave perimeter surface having a radius measured from the vertical axis that varies by between one and five percent at four equally spaced positions around the ring perimeter.

A blow-molded bottle comprising a base, a side wall having a lower margin joining the base, the side wall extending upward from the base to an upper margin, an inwardly indented ring joining the upper margin of the side wall to a shoulder portion, the shoulder portion extending upward above the inwardly indented ring and inward to a neck surrounding a vertical axis below a finish defining a opening adapted to accept a closure, the shoulder including a circumferentially continuous outwardly extending upper peripheral margin adjoining the neck, an outwardly protruding ring immediately above the inwardly indented ring, and a flexible concave perimeter surface joining the upper peripheral margin to the outwardly protruding ring, the vertical midpoint of the flexible concave perimeter surface having a radius measured from the vertical axis that increases by between one and five percent at several equally spaced positions around the concave surface perimeter, the shoulder responding to the presence of a vacuum within the bottle by forming linear segments between the upper peripheral margin and the outwardly protruding ring coincident with the equally spaced positions.

A blow-molded bottle comprising at least one portion having a circumferentially continuous outwardly extending upper peripheral margin, an outwardly protruding ring located below the upper peripheral margin, and a flexible concave perimeter surface joining the upper peripheral margin to the outwardly protruding ring, the vertical midpoint of the flexible concave perimeter surface having a radius measured from the vertical axis that varies by between one and five percent at between three and five spaced positions around the ring perimeter, the concave perimeter surface responding to the presence of a vacuum within the bottle by forming linear segments between the upper peripheral margin and the outwardly protruding ring coincident with the spaced positions.

A blow-molded bottle comprising at least one portion having a circumferentially continuous outwardly extending upper peripheral margin, an outwardly protruding ring located below the upper peripheral margin, and a flexible concave perimeter surface joining the upper peripheral margin to the outwardly protruding ring, the vertical midpoint of the flexible concave perimeter surface having a radius measured from the vertical axis that is greater than (3/π) (sin π/3) (R1+R2), and less than (6/π) (sin π/6) (R1+R2), where R1 is the outermost radius of the upper peripheral margin, and R2 is the radius of the outwardly protruding ring, the concave perimeter surface responding to the presence of a vacuum within the bottle by forming linear segments between the upper peripheral margin and the outwardly protruding ring, the linear segments being separated from each other by concave indented portions.