Stopper for Aseptic Containers

The present invention relates to a stopper for aseptic containers.

Conventionally, stoppers for aseptic containers include a type made from plastic material, embodied substantially as a cylindrical plug, which affords a plurality of projecting and reentrant annular profiles compassing its outer cylindrical periphery and matched to similar reentrants and projections afforded internally by the mouth of a container. Such stoppers are fashioned generally by bringing together two mold or die halves, of which the relative internal surfaces bear semicylindrical impressions corresponding each to one half of the stopper. When brought together, the two die halves unite along two diametrically opposite longitudinal generators of the cylinder.

Stoppers of the type in question tend however to be adversely affected by the appearance of flashes or fins, which are attributable to lack of precision in the molding operation, or to worn dies.

This excess material constitutes a serious problem, as the fit between the stopper and the mouth of the relative container becomes less exact; consequently one has the possibility that air will penetrate the container, and render the entire aseptic filling process ineffective.

The object of the present invention is to overcome the drawback mentioned above, and in particular to ensure a faultless fit between the stopper and the mouth of the container, such that the aseptic state of a product can be guaranteed.

The stated object is fully realized with a stopper for aseptic containers according to the present invention.

Such a stopper is fashioned from plastic material, and consists in a plug of substantially cylindrical embodiment, exhibiting a plurality of annular projections and reentrants compassing its external circular periphery of which the shape is identical and complementary to that of similar profiles afforded internally by the mouth of a container to be stoppered.

An essential features of the invention is that any flashes left on the plug by molding are annular, and occupy an area remote from the area of contact between the plug and the mouth of the container.

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which:

FIG. 1 illustrates the stopper in partial section through a vertical diametral plane;

FIG. 2 illustrates the mouth of a container, viewed in section through the same plane as that of FIG. 1;

FIG. 3 illustrates the stopper inserted into the mouth of the container, viewing in section through the same plane as that of FIGS. 1 and 2;

FIG. 4 is a detail of the stopper and the mouth of the container, illustrating a possible alternative embodiment of the invention.

With reference to the drawings, 1 denotes a plug of substantially cylindrical embodiment, molded in such a way as to incorporate annular projections 2 and reentrants 3 which are substantially identical to matching annular profiles 4 and projections 5 afforded internally by the mouth 6 of a container (not illustrated). The annular projections 2 are located below a top edge 7 of the plug, such that when the container is stoppered, these will settle on the profiles 4 whilst the reentrants 3 will be forced over the projections 5 of the mouth.

The plug is molded by bringing together two dies (not illustrated), in a movement coinciding with the axis of the stopper; the one die carries an internal impression of the cylindrical part of the plug below the annular projections 2, and the other an internal impression of the top edge 7, in such a way that any surplus material issuing from the mold will appear as an annular flash 10 around the topmost edge 7 of the plug, rather than as fins issuing from the outer cylindrical surface. Thus, according to the invention, the formation of any such annular molding flashes will in no way affect the fit and sealing action between the plug 1 and the mouth 2 of the container; also, by totally avoiding the formation of molding fins on the external lateral surface of the plug, it becomes possible to enhance the sealing action and eliminate problems connected with the penetration of air into containers.

In a possible alternative embodiment of the stopper illustrated in FIG. 4, the projections 2 afforded by the plug 1 are shaped in such a way as to include an annular groove 8 of substantially semicircular section, which is designed to fit over an annular profile 9 of substantially rounded trapezoidal section offered by the uppermost rim of the mouth of the container.