Tamper-resistant container cap

Abstract

A cap for a container neck has a skirt formed with beads on its inner surface which cooperate with matching grooves in the neck to retain the cap in place when the skirt is intact. A circumferential groove is formed in the skirt intermediate the beads joined with a second groove extending to the bottom edge of the skirt. A tab projecting beyond the skirt is gripped and pulled, causing the skirt to tear upward and then circumferentially, thereby removing the lower bead and permitting the top of the cap to be removed and re-closed. A flange is formed on the exterior of the skirt immediately above the level of the first groove. The flange prevents the skirt from tearing upward above the first groove. It also facilitates prying the cap off the neck when the lower part of the skirt has been torn off. Various flange shapes are disclosed, several of which are shaped to defeat attempts to pry off the cap before the skirt is torn. A flange which has a groove formed in its bottom surface adjacent the skirt is particularly tamper-resistant, as is a flange wherein the top and bottom surfaces converge outwardly. The cap beads may be continuous or interrupted. The cap may be provided with an inner skirt or plug to fit into the neck of the container.