Patent attributes
A closure for a container having an opening includes a base cap and an overcap that form a chamber adjacent the opening which is sealed from the contents of the container by a frangible membrane having an inclined line of weakness and by a hinge member having a pocket extending downward adjacent lower and upper terminuses of the line of weakness. The overcap includes a cutting member received within the pocket that severs the line of weakness upon substantial rotation of the overcap with respect to the base cap. A pushing member may cooperate with a cam member to deflect open the membrane upon severance. The pocket may include a stop for the cutting member. The base cap may include a cylindrical structure having an upwardly inwardly projection member to form a seal with an thickened upper portion of the overcap skirt to protect against penetration into the chamber.