Screw cap with tamper-proof hold ring

A screw cap for covering the opening in the neck of a container, comprising:

• the cap being a single molded member comprised of a semi-rigid material, having the ability to flex elastically;
• the cap comprising:
• a cap body, including an end for covering the opening in the container neck and including a lower edge away from the end;
• a closed, annular, hold ring for surrounding the container below the neck thereof;
• the ring being connected to the cap body at the lower edge of the cap body by a plurality of attachment tabs which are sized and shaped for being breakable upon being stressed more than a predetermined amount;
• a plurality of lock-lugs attached to the ring and protruding inwardly from the ring and also toward the end of the cap body, and the lock-lugs terminating at respective free ends, which free ends are adapted for engaging an element of the container to prevent raising of the lock-lugs past that container element;
• the lock-lugs protruding in such a manner that a circle passing through the free ends of the lock-lugs has a diameter less than the diameter of the container element;
• a flange for providing a generally non-breakable connection between the cap body and the ring, said flange being flexible for permitting the cap body to pivot off the hold ring with the flange serving as the pivot hinge, said flange being located between two tabs of said plurality of attachment tabs.