US Patent 8113370 Plastic container having vacuum panels

A container structure for a hot fill liquid may employ an upper portion defining a mouth, a shoulder portion integrally formed with and extending downward from the upper portion, a bottom portion defining a base, and a body and sidewall extending between and joining the shoulder and bottom portions. The sidewall may employ a pair of opposing columns oriented diagonally relative to the base and concave inward relative to a container central vertical axis before the container is filled. The columns become concave inward to a lesser extent when the bottle is under an interior vacuum. The sidewall may also employ a pair of opposing, compound angle vacuum panels oriented diagonally relative to the base. A vacuum initiator groove is formed in each of the vacuum panels to initiate panel movement during liquid content cooling. The vacuum initiator groove is generally coincident with a vacuum panel longitudinal centerline.