Patent ID: 8251972

Claim:
A perforable closure for a container, comprising (a) a lower annular portion for connecting the closure externally with an upper end of the container; (b) a generally flat and uninterrupted upper end portion perforable by a perforator when the perforator is inserted into the closure for delivering fluid from the container; and (c) an elastic intermediate wall portion between said lower and upper portions, said lower annular, intermediate wall and upper end portions being coaxially arranged and integral to form a unitary closure, said intermediate wall portion having a cylindrical inner wall having a diameter less than the diameters of said annular and upper end portions, said intermediate wall portion including a first pair of ribs and a second pair of opposed ribs spaced from and orthogonal to said first pair of ribs, said first and second pairs of ribs extending outwardly with respect to the closure intermediate wall portion within planes extending through a longitudinal axis of the closure, said inner wall portion guiding said perforator as it is inserted into the closure with said intermediate wall portion expanding outwardly and said ribs providing a gripping force for ripping the perforator when the perforator is inserted into the closure.