Resilient material screw top for containers

#This invention relates to a screw top made from an elastic or resilient material for containers, particularly beverage bottles, wherein the screw top is internally threaded for threading onto the container.

#Numerous different constructions for screw tops of the general type to which this invention relates are known, including screw tops made of resilient material such as plastic. Numerous developments have been made in this field, particularly in connection with screw tops intended for use with containers which are not produced in a careful and precise manner such as beverage bottles. Such bottles tend to suffer from various irregularities such as noncircular tops resulting from imprecise manufacturing techniques as well as indentations, brokenaway parts and the like, depending upon the country of manufacture and the number of movements or cycles between the filling location and the consumer. Tops have been developed for such bottles which can provide a perfect seal despite such irregularities. However, it is necessarily the case that such tops involve considerable technical expenditure and effort and require a relatively large amount of material.

#A significant consideration in this field is that numerous very large beverage manufacturers use their own unique, unmistakably recognizable bottles. These bottles are manufactured to a relatively high standard with regard to dimensional accuracy and are substantially free from the aforementioned irregularities because defective bottles are eliminated. In connection with these bottles, it is unnecessarily expensive to use tops which are made to satisfy more demanding circumstances than those which exist. Thus, if it is possible to produce a simpler screw top which has adequately high quality and in which the simplicity leads to a saving of material, such a saving can lead to enormous economies in manufacture and particularly in material cost because of the vast number of such tops which are required, even though the material saving for each individual top seems to be virtually without significance, being in the order of only about 0.1 gram.

#In order that the manner in which the foregoing and other objects are attained in accordance with the invention can be understood in detail, a particularly advantageous embodiment thereof will be described with reference to the accompanying drawings, which form a part of the specification, and wherein

#FIG. 1 is a partial side elevation of the top of a container and a screw top in accordance with the invention with the screw top partially screwed onto the container; and

#FIG. 2 is a view similar to FIG. 1 but with the screw top completely screwed onto the container.

#As shown in FIG. 1, the container 1 has a top portion with external threads to receive a screw top and the top in accordance with the invention includes a cap portion 2 which extends generally transversely across the container opening and a cylindrical ring portion 3 which extends axially away from the cap portion and which is fixedly attached thereto, the ring and cap portions normally being integrally formed of the same material. The ring portion is provided with internal threads 30. The cap portion 2 can also have an axially extending portion 4 which enters and engages the mouth of container 1, but which is of no particular significance in connection with the present invention. If provided, portion 4 serves as a first seal between the inside of the container and the opening adjacent annular surface 10 which surrounds the container opening.

#The features which are of significance to the present invention include an annular sealing washer 5 which is carried by ring 3 and extends radially inwardly therefrom, the washer having a base or root 51 attached at a location 52 which is above the internal thread 30, i.e., between the thread and the inner surface of cap portion 2, and extends in a plane which is substantially parallel with the inner surface 20 of the cap portion at a distance A thereform, when the screw top is apart from, or only partially screwed onto, the container. As will be seen in the figures, sealing washer 5 is very thin. Its thickness d measured adjacent root 51 is only a fraction of its radial length L, the length being about 5 times the indicated thickness and, preferably, even less. The sealing washer thus also extends parallel with the annular surface 10 surrounding the opening of container 1 and is intended to seal against that surface and, particularly, against the outer circular edge 11 of that surface under pressure. The manner in which this takes place will be described.

#A pressure rib 6 is formed on the underside 20 of cap portion 2 and extends axially toward sealing washer 5. Particularly for manufacturing reasons, the axial height H of the rib 6 should be smaller than dimension A as indicated in FIG. 1. Pressure rib 6. is an annular ridge which has a circular end or tip 61 which can be either sharp or slightly rounded.