Tamper indicating closure

Abstract

 A threaded cap composed of a cylindrical cup provided with an internal thread and with a sealing ring (4) that is coupled to the edge of the cup by means of a plurality of bridges (5) that form a fracture line and is provided with a plurality of teeth (7) that protrude inwardly from its rim and are directed obliquely towards the cup, the teeth being shaped like cylindrical sectors the convexity whereof is directed towards the inside of the cap.

Description

[0001] The present invention relates to a threaded cap provided with a sealing ring.

[0002] Caps of this type are already commercially available. They comprise a cylindrical cup that is internally threaded in order to be screwed on the top of the container (bottle). A ring is coupled to the rim of the cup by means of breakable bridges and is internally provided with engagement elements constituted by teeth or flaps which, when the cap is applied so as to close the container, engage below a collar of the container. By unscrewing the cap, the teeth abut against the collar and retain the ring, whereas the resulting axial traction force breaks the bridges, allowing to remove the cup.

[0003] In conventional caps there is the problem of allowing the teeth, during application on the container, to expand outwards in order to pass beyond the collar and then retract again below said collar, so as to prevent the cap from being unscrewed together with the ring. Currently commercially available caps have some substantial drawbacks that can be ascribed to the structure of the teeth and to the technical difficulties in producing said teeth, also in view of the fact that the teeth must be flexible in order to allow extraction of the caps from the mold.

[0004] A principal aim of the present invention is to provide a cap capable of substantially obviating the shortcomings of conventional caps.

[0005] This aim is achieved with a threaded cap of the type composed of a cylindrical cup provided with an internal thread and with a sealing ring that is coupled to the edge of the cup by means of a plurality of bridges that form a fracture line and is provided with a plurality of teeth that protrude inwardly from its rim and are directed obliquely towards the cup, characterized in that said teeth are shaped like cylindrical sectors the convexity whereof is directed towards the inside of the cap.

[0006] Further particularities of the present invention will become apparent from the following description on the basis of the accompanying drawings, wherein:

figure 1 is an axial sectional view of a screw cap according to a first embodiment;

figure 2 is an enlarged-scale view of a detail of the cap of figure 1;

figure 3 is an axial sectional view of a cap according to a second embodiment;

figure 4 is an enlarged-scale view of a detail of the cap of figure 3;

figures 5 and 6 are axial views of the caps of figures 1 and 3 respectively;

figure 7 is a perspective view of a tooth of the cap of figure 1;

figure 8 is a view of a cap according to figure 1, applied to a container;

figure 9 is a perspective view of a tooth of the cap of figure 3;

figures 10 and 11 are enlarged-scale views of two further different embodiments of the cap.

[0007] With reference to figures 1, 2, 5, 7, and 8, the reference numeral 1 generally designates a cap according to the present invention, obtained by molding plastics according to conventional methods. The cap 1 comprises a cylindrical cup 2, inside which a thread 3 is formed. A ring 4 protrudes from the rim of the cylindrical wall of the cup and is connected to said rim by a plurality of bridges 5 that are spaced by slits 6 that form a fracture line. The bridges and the slits can be produced in any manner, for example during the molding of the cap by providing appropriate shapes of the mold or by means of cutting operations performed after molding.

[0008] In order to ensure that the cap cannot be fraudulently removed after it has been screwed onto the container, on the inner face of the ring 4 there is provided a plurality of teeth 7 having the purpose of retaining the cap on the container. Said teeth are constituted by cylindrical sectors having a substantially trapezoid-like shape and the convexity whereof is directed towards the inside of the ring. The teeth are joined to the free rim of the ring 4 by means of the side 8 that corresponds to the shorter base of the trapezoid; said teeth instead rest on the inner face of the ring 4 by means of the sides 9 and 10 that correspond to the legs of the trapezoid. The height of the teeth 7 is such that their upper side 11 lies directly below the line of the slits 6.

[0009] The cylindrical sector-like shape causes the teeth 7 to have a certain flexibility, in that they can flatten against the wall of the ring 4 when they are stressed radially, and a high flexural strength when they are subjected to loads applied edgeways.

[0010] By virtue of these characteristics, when the cap is applied to a container 12, the teeth 7, by flattening against the inner face of the ring, can easily slide on the collar 13 that retains the container 12 until, after passing beyond it, by virtue of the elasticity of the plastic material, they regain their stable shape to engage below the collar 13 by means of the rim 11.

[0011] It should be noted that in the position in which they are engaged below the collar 13, the sides 9 and 10 of the teeth rest against the inner face of the ring 4, so as to prevent the teeth from rotating outwardly, thus increasing their resistance to loads applied edgeways.

[0012] The described cap is susceptible of numerous modifications and variations.

[0013] Figures 3, 4, 6, and 9 illustrate an embodiment in which the teeth 7 are connected to each other by thinner intermediate sectors 14 connected to the lower rim of the ring 4. Figure 10 is a view of a different embodiment that can be applied to the caps of the above-described figures, which consists of a rib 15 protruding inwardly from the lower rim of the ring 4 below the lower side 8 of the teeth. A similar solution is shown in figure 11, where furthermore the rib 16 forms a sort of support for the lower side of the teeth 7.

[0014] The rib 15 or 16 strengthens the region where the teeth 7 couple to the ring 4. Moreover, the rib 15 or 16 facilitates the folding of the teeth in the position inside the cup after extraction of the cap from the mold.

[0015] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. Threaded cap of the type composed of a cylindrical cup (2) provided with an internal thread (3) and with a sealing ring (4) that is coupled to the edge of the cup by means of a plurality of bridges (5) that form a fracture line and is provided with a plurality of teeth (7) that protrude inwardly from its rim and are directed obliquely towards the cup, characterized in that said teeth (7) are shaped like cylindrical sectors the convexity whereof is directed towards the inside of the cap.

2. Threaded cap according to claim 1, characterized in that said teeth (7) have a substantially trapezoid-like shape, in which the side corresponding to the shorter base of the trapezoid is joined to the free rim of the ring (4), whereas the sides corresponding to the legs of the trapezoid rest on the inner face of the ring (4), the height of the teeth being such that their upper side, which corresponds to the longer base of the trapezoid, is at a level lying directly below the fracture line of the ring.

3. Threaded cap according to claim 1 or 2, characterized in that the teeth are connected to each other by thinner intermediate sectors (14) connected to the lower rim of the ring (4).

4. Threaded cap according to one of the preceding claims, characterized in that it comprises a rib (15) that protrudes from the lower rim of the ring (4) towards the inside of the cup (2) below the side where the teeth couple to the ring (4).

5. Threaded cap according to one of claims 1 to 3, characterized in that it comprises a rib (16) that protrudes from the lower rim of the ring (4) towards the inside of the cup (2), forming a sort of support for the side where the teeth couple to the ring (4).

6. Threaded cap provided with a sealing ring, according to what can be deduced from the above description and from the accompanying drawings.

Drawing