Abstract: One form of a cap for a container includes an internal part and an external part relatively movable with respect to one another among closed, intermediate and open cap positions. Complementary structures protrude from the internal and external parts for dictating relative positions of the internal and external parts as the parts are initially joined together. Interengaging elements on the internal and external parts secure a selected portion of one of the internal and external parts to the other after joining the parts together. A breakable seal between the selected portion of the one of the internal and external parts and the remainder of the one of the internal and external parts, when broken, allows the internal and external parts to move relative to one another. Variations are also disclosed.

Abstract: The combination of a cap and a container. The cap is provided with an internal structure and an external structure movable with respect to one another among closed, intermediate and open cap positions. A plurality of hooks is provided on the internal structure for grasping a bead on the container when the cap is in the closed and intermediate cap positions. Ribs, disposed on the external structure, include upper extremities which prevent the cap from being placed directly from the closed cap position into the open cap position. Pressure relief of the container, if any, occurs in the intermediate cap position. The external structure of the cap defines a safety seal for indicating that the cap has been moved from the closed position.