Abstract: A screw-type linerless closure molded of resilient plastic is provided with a novel combination of sealing elements for accommodating storage overloads, large container tolerances and variable surface textures, to secure reliable sealing over a wide range of conditions. Operation of the principal sealing ridge is assisted by an adjacent pressure-relief groove, or grooves, and by separate overload-resisting elements. A supplementary sealing flange is also provided to accommodate irregularities of the mating surface of the container.

Abstract: A screw-type linerless closure molded of resilient plastic is provided with a combination of sealing structures directed toward the particular characteristics of glass containers as used for pressurized beverages, though it may also be used for other containers. Novel means for accomodating large dimensional tolerances and special surface conditions are used, along with prior art constructions, to secure improved sealing under a wide variety of conditions.