As is known, there is a need to prevent the bottle from being refilled with an alcoholic beverage which is of poor quality or, in any case, is not the original beverage, once its original content of good-quality alcoholic beverage has been used up.

Whereas closures of the type specified are satisfactory from various points of view and are used extensively, they do not offer an effective guarantee against any attempts at unauthorized refilling. In fact, if sufficient transverse force is exerted on the free end of the spout, the connection breaks so that the spout can be removed complete with the valve for preventing refilling.

After refilling, the spout can easily be replaced, the connection possibly being repaired with a suitable glue. The closure thus substantially regains its initial appearance with no remaining trace of the tampering with the closure so that the consumer is deceived.

The problem upon which the present invention is based is that of devising a closure of the type specified which has structural and functional characteristics such as to overcome the aforementioned disadvantage.

This problem is solved by a closure of the type specified which is characterized in that the connection comprises a double ultrasound-welding seam forming a fixed joint between the spout and the sleeve.

Further characteristics and the advantages of the closure according to the present invention will become clear from the following description of an embodiment thereof, given by way of non-limiting example with reference to the appended drawings, in which: Figure 1 shows a closure according to the invention in elevation and in section, Figure 2 shows a detail of the closure of Figure 1, in elevation, in section, and on an enlarged scale, Figure 3 is a partially-sectioned, perspective view of a detail of the closure of Figure 1, Figure 4 is a section of a detail of the closure of Figure 1, taken on the line IV-IV.

With reference to the appended drawings, a security closure for a bottle 2 for good-quality alcoholic beverages is generally indicated 1.

The bottle 2 has a neck 3 with a mouth 4. The neck 3 has a groove 5 defining a shoulder 6, and a plurality of teeth 7 defining a splined profile 8.

The security closure 1 comprises a spout 9 which is in abutment with the mouth 4 of the bottle 2 and contains a valve 10 for preventing refilling, that is, essentially, a non-return valve.

The spout 9 has a tubular shell 11 which is produced by injection-moulding of a suitable plastics material, preferably polycarbonate. The shell 11 has an axis x-x and has a rim 12 with an anti-drip function formed in an upper end portion Ila of the shell 11, a first flange 13 and a second flange 14 which project from a portion llb of the shell 11 in the region of the mouth 4 of the bottle, and an external thread 15 formed around an intermediate portion llc of the shell 11 between the anti-drip rim 12 and the first flange 13.

The first flange 13 and the second flange 14 are spaced apart axially. More precisely, they are spaced apart axially by a distance D of between 3mm and 5mm, preferably 4mm.

A cap 16 is screwed onto the spout 9 and, for this purpose, has an internal thread 17 matching the external thread 15 of the spout 9.

The security closure 1 comprises a sleeve 18 associated coaxially with the spout 9 and coupled thereto by means of a connection 19.

The sleeve 18, which is produced by injection- moulding of a suitable plastics material, preferably polycarbonate, comprises an upper end 20 and a lower end 21. A substantially toroidal enlargement is formed externally at the upper end 20 and constitutes a collar 22.

Starting from the upper end 20, the sleeve 18 comprises internally, snap-fixing means 23 engaged with the bottle 2 and, more precisely, engaged with the shoulder 6 in order to hold the closure on the bottle, as well as ribs 24 extending axially and matching the teeth 7, constituting a splined profile 25 matching the splined profile 8 of the bottle, for restraining the sleeve angularly on the bottle.

The snap-anchoring means 23 are formed by a plurality of teeth 26, in the embodiment shown, three teeth having sawtooth-like profiles, distributed uniformly on the circumference, and each having an angular extent A of about 60".

In a portion 27 of the sleeve 18 disposed between the collar 22 and the snap-fixing means 23, there is a plurality of recesses 28, three recesses in the embodiment shown, each formed in the region of a respective tooth 26, and with the same angular extent.

It should be noted that, in the security closure 1 according to the invention, in the portion 27, between one recess and another, the sleeve 18 has a fairly large thickness B, particularly, a thickness of between 0.8 and lmm, preferably a thickness of 0.9mm, whereas, in the region of each recess, it has a relatively limited thickness C, particularly a thickness of between 0.3 and 0.5mm, preferably a thickness of 0.4mm.

It should also be noted that the recesses 28 have sharp corners extending axially and indicated 29 so that the change in the thickness of the sleeve between the thickness B and the thickness C is abrupt, defining breakage-initiation points in the region of the sharp corners.

In the security closure 1 according to the invention, the connection 19 comprises a double ultrasound-welding seam 31 and 33 forming a fixed joint 30 between the spout 9 and the sleeve 18.

In particular, the double welding seam 31 and 33 comprises a first, annular ultrasound-welding seam 31 formed between the first flange 13 and a first annular step 32 formed in the region of the collar 22, and a second annular ultrasound-welding seam 33 formed between the second flange 14 and a second annular step 34 formed in the region of the collar 22.

The two steps 32 and 34 are also spaced apart axially by a distance equal to D and each has a respective moulding 35 or 36, constituting a so- called energy director for favouring the fixing together of the parts when the ultrasound is applied.

The welding seams 31 and 33 are also spaced apart axially by a distance equal to D, that is, by a distance of between 3 and 5mm, preferably by a distance of 4mm.

The spout thus has a portion which is inserted for a predetermined axial distance into a corresponding portion of the sleeve so as to be fitted therein.

The collar 22, the two flanges 13 and 14, and the portion llb of the spout disposed between the flanges form an annular, box-like body 37 in which an annular chamber 38 is defined.

It has been found, upon attempting to remove the spout from the bottle by exerting a considerable transverse force on the spout at the level of the anti-drip rim, that the fixed joint offers an extremely high resistance to breakage, by virtue of the double welding seam. When faced with an extremely large force, the fixed joint in any case breaks with an irregular and jagged breakage of the box-like body such that, if the closure is reassembled, it offers clear visible proof of the breakage which has taken place in the box-like body which is poorly reassembled with the annular chamber visible here and there.

If the breakage does not take place at the level of the fixed joint but in the region of the portion of the sleeve disposed between the collar and the fixing means, it has been found that, in this case also, the breakage takes place in a jagged and irregular manner because of the different thicknesses of the sleeve in this portion so that, in this case also, the closure cannot be reassembled in a manner such as clearly not to have been tampered with.

The main advantage of the closure according to the present invention lies in the fact that it shows in an unusually visually conspicuous manner that a breakage has taken place as a result of attempted unauthorized refilling.

A further advantage of the closure according to the present invention lies in the fact that the closure can easily be fitted on the bottle without any danger of collapse of the portion of the sleeve disposed between the collar and the fixing means when the sleeve is fitted and snap-fixed on the bottle. In fact, this portion of the sleeve is unusually stiff by virtue of its different thicknesses.

Another advantage of the closure according to the present invention is apparent during the manufacture of the sleeve by injection moulding of plastics material. In fact the collar is filled with the plastics material in an optimal manner inside the mould since the portion of the sleeve disposed between the collar and the snap-fixing means is fairly thick between one recess and another.

Naturally, in order to satisfy contingent and specific requirements, an expert in the art may apply to the above-described closure many modifications and variations all of which, however, are included within the scope of protection of the invention as defined by the following claims.