US Patent 7314065 Irreversible plug assembly

A plug assembly for a tube includes a tapered wedge and a sleeve. The sleeve fits over the wedge and is placed in a tube. Relative movement of the wedge and the sleeve causes the sleeve to expand and plug the tube. The exterior surface of the wedge and the interior surface of the sleeve include annular grooves. One or more compression rings in either the grooves in the sleeve or wedge permit motion of the sleeve relative to the wedge only toward the large diameter portion of the wedge. This prevents the sleeve from separating from the wedge after being installed in a tube.