MXPA00000828A - Plastic screw cap with pilferproof ring - Google Patents

Abstract

A plastic screw cap (1) comprising a cylindrical cup (2) provided with an internal thread and with a pilferproof ring which is connected to the rim of the cup by means of a plurality of bridges (9) which form a circular fracture line, the ring having a plurality of internal flaps (12) which are inclined towards the bottom of the cup;the pilferproof ring comprising a cylindrical wall (8), whose thickness is such that it is substantially flexible in a radial expansion direction, a rim which is connected to the rim of the cup by the bridges, and an opposite rim which is connected to an internal annular bead (11) whose inside diameter is smaller than the inside diameter of the wall and whose thickness is significantly greater than the thickness of the wall, a plurality of flaps (12) protruding from the region connecting the flexible wall and the internal annular bead and having such a thickness as to acquire substantial rigidity with respect to radial stresses.

Description

TECHNICAL FIELD The present invention is attached to a plastic screw cap with a tamper-proof ring.

TECHNICAL BACKGROUND Such lids are commercially available and comprise a cylindrical structure which is internally threaded to be screwed onto the upper part of the container (bottle). The so-called burglary-proof ring is attached to the rim of the tray by breakable bridges and is provided internally with coupling elements constituted by flaps which, when the lid for closing the container is applied, is coupled below a retaining collar of the container. When unscrewing the cover, the flaps are joined with the collar and retain the ring, while the consequent axial pulling force breaks the bridges. In conventional caps the problem is to ensure that during application to the container, the flaps may expand or otherwise deform to move towards the bottle retaining collar and subsequently contract again below said collar, in such a way as to allow that the burglary-proof ring separates during unscrewing and clearly indicates that the container has been opened. The commercially available covers present some drawbacks that are due to the structure of the teeth and to the technical difficulties to provide them, also as regards the problems related to the molding steps, particularly with the extraction of the mold caps. US-5,107,998 discloses a closure with a burglary-proof ring having an inwardly directed flange and a plurality of internal flaps secured so that they can rotate toward the flange. The flaps, during the positioning of the closure on a threaded finish of a container engages in a recess and during the removal of the closure is rotated to engage the upper surface of the flange.

DESCRIPTION OF THE INVENTION With the present invention it is desired to provide a plastic lid that can substantially counteract the drawbacks of conventional lids. This is achieved by a threaded plastic cap for sealing a container having a threaded finish and a collar adjacent said threaded finish, said cap comprising a cylindrical structure provided with an internal thread and with a theft-proof ring which is connected with the rim of the cylindrical structure by means of a plurality of bridges forming a fracture line, said ring having a plurality of internal flaps inclining towards the lower part of the cylindrical structure; characterized in that the burglary ring comprises a cylindrical wall, the thickness of which is such that it is substantially flexible in a radial expansion direction, a flange which is connected to the flange of said cylindrical structure by said bridges and an opposite flange which is connected to an annular inner edge whose internal diameter is smaller than the internal diameter of said wall and whose thickness is significantly greater than the thickness of said wall; and in that a plurality of flaps protrude from the region connecting said flexible wall and said inner annular edge, said flaps have such thickness that they acquire a substantial rigidity with respect to the radial stresses, in such a way that during the removal of the splice from the cover of the flaps in said collar produces an expansion of said edge in the region connected to the mentioned wall.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will be apparent from the following detailed description on the basis of the accompanying drawings where: Figure 1 is an axial sectional view of a screw cap according to the first embodiment; g¡gm & Figure 2 is an enlarged scale view of a detail of the lid of Figure 1; Figure 3 is an axial view of the lid of Figure 1; Figure 4 is an enlarged scale view of a detail of a lid in accordance with a second embodiment; Figure 5 is a view of a lid according to Figure 1, applied to a container; Figures 6 to 8 are views of the lid in successive steps of the application to the container; Figure 9 is a view of the lid during unscrewing.

WAYS TO DEVELOP THE INVENTION With reference to Figures 1, 2, 3 and 5, one generally designates a cap in accordance with the present invention, which is formed by plastic molding in accordance with known methods. The lid 1 comprises a cylindrical structure 2 which is composed of a lower part 3, which is covered internally by a liner 4, and of a cylindrical wall 5 inside which a thread 6 is formed. A ring theft-proof 7 protrudes from the rim of the cylindrical wall 5 of the cylindrical structure 2 and is composed of a cylindrical wall 8, wherein a rim is connected to the rim of the cylindrical structure 2 by a plurality of bridges 9 separated by slots 10 and JH ^ m ^ ^ U the opposite flange has an internal bridging edge 11. The bridges 9 and the slots 10 can be provided in any way, for example during the molding of the lid by providing suitable shapes of the mold or by cutting operations after the molding The wall 8 has a thickness significantly smaller than that of the wall 5 of the cylindrical structure in such a way that, by using the elasticity of the plastic material, it can sustain any widening that occurs in the region for connection with the annular edge 11, to assume a tapered shape tapering toward the bottom of the cylindrical structure during application to a container 17. The edge 11 is significantly thicker than the wall 8 and protrudes from the inner face thereof, such that the diameter The internal thickness of the edge is significantly smaller than the internal diameter of the wall 8. The greater thickness of the annular edge 11 ensures that said edge can be broadened less than the wall 8 with respect to the elasticity of the plastic material from which the cover is made. The difference in the internal diameter between the edge 11 and the wall 8 forms a step-shaped connection region, from which a plurality of flaps 12 protrude towards the internal part of the cylindrical structure 2; said flaps are inclined towards the lower part 3 of the cylindrical structure with an inclination of approximately 60 °. The flaps 12 are equidistant, mutually separated by sectors 13, and preferably thicker than the wall 8, but thinner than the edge 11. Furthermore, the upper and lower faces of the flaps 12 are connected to the internal faces of the wall 8. of the edge 11 by curved regions 14, 15. The different thickness of the wall 8, the edge 11 and the flaps 12 on the one hand cause a simpler application of the lid to the threaded finish of the container 17 and, on the other hand, a retention firmer of the burglary-proof ring 7 under the collar 16 of the container 17, to which the lid 1 is applied and, finally, a more secure separation of the latter when the lid is unscrewed. As shown in Figure 6, during the application of the lid 1 to the container 17, the joining of the flaps 12 on the collar 16 in fact causes the edge 11 to widen, to which the wall 8 joins, while the diameter the opposite end of the edge 11 remains substantially unchanged. The wall 8, due to its great flexibility, follows the widening of the edge 11 (see Figure 7). In practice, the edge 11 undergoes torsion with respect to the axis A of the lid and therefore the ends of the flaps 12 and the lower edge of the edge 11 move towards a cylindrical plane which is more outwardly than the plane of natural rest and facilitates its sliding on the collar 16 of the container 17. When the flaps 12 have moved below the collar 16, the elastic memory of the material ensures that the edge 11 and the flaps 12 again substantially assume their natural position (see Figures 8 and 5), wherein the flaps 12 protrude below the collar 16.

-. . ^^^ IB ^ ... , .. ^ * It should be noted that when the lid 1 is removed from the container 17, the flaps 12 are joined under the collar 16 and, thanks to the flexibility of the wall 8, produce a fold inward of the edge of the edge 11 to which the wall 8 is connected. In this way, the flaps 12 move towards the container 17, ensuring more effective splicing of the flaps under the collar 16 and a safer separation of the theft-proof ring 1. In this position, the angle between the flaps and The axis A of the cap during the rupture of the ring theft-proof is >; 90 ° (see Figure 9). It is evident that it is important that the flaps have a thickness that allows them to acquire, in accordance with the natural elasticity of the plastic material of which the cover is made, a substantial rigidity for the radial forces that allow deformation by torsion of the edge and by thus the double orientation of the flaps in a position to slide along the collar of the container during the application of the lid and a position where they have an interference fit below the collar during unscrewing of the aforementioned lid. The cover described is susceptible to various modifications and variations. With respect to Figure 2, Figures 4, 6-9 illustrate a modality wherein the flaps 12 are provided, in a lower region, with a reinforcing tooth 18. Alternatively, the tooth may be provided on the upper surface of the tooth. the lapels.

In a different embodiment, the edge 11 has, in the intermediate sectors 13, a smaller cross section than in the flaps 12, in such a way that it affects the ability of the flaps 12 to expand outwards. In the practical embodiment of the invention, the shapes and dimensions, as well as the materials used, can be any according to the requirements. The descriptions in the Italian patent application no. BO97A000457 for which this application claims priority are incorporated herein by reference.

Claims (4)

NOVELTY OF THE INVENTION CLAIMS

1. A threaded plastic cap for sealing a container having a threaded finish and a collar adjacent said threaded finish, said cap comprising a cylindrical structure (2) provided with an internal thread and with a ring that is burglary proof ( 7) which is connected to the rim of the cylindrical structure (2) in the manner of a plurality of bridges (9) which form a circular fracture line, said ring (7) has a plurality of internal flaps (12) that inclining towards the lower part (3) of the cylindrical structure (2), the theft-proof ring (7) comprises a cylindrical wall (8), whose thickness is such that it is flexible substantially in a direction of radial expansion, a first flange which is connected to the flange of said cylindrical structure (2) by said bridges (9) and its second opposite flange connected through a connection region to an internal annular edge (11) whose internal diameter is smaller than the internal diameter of said wall (8) and whose thickness is significantly greater than the thickness of said wall (8); further characterized in that said ring (7) further comprises a plurality of flaps (12) protruding from said connecting region connecting said flexible wall (8) and said inner annular edge (11), said flaps (12) having such thickness that acquire a substantial rigidity with respect to the radial efforts and being separated > aaari, g - 'nt ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡m ¡m HÉítttÉ &ampíflM by intermediate sectors (13) thicker than the flexible wall (8) and thinner than said edge (11) in such a way that during the removal of the cover (2) the junction of the flaps (12) in said collar (16) causes the elongation of said ring (7) in the connection region where said flaps (12) protrude, with respect to the edge ( 11) turning inwards near and under said collar (16)

2. A screw cap according to claim 1, further characterized in that said flaps have a thickness that is intermediate from the thickness of said edge and the thickness of said wall

3. A threaded cap according to one of the preceding claims, characterized in that the flaps have a reinforcing tooth on at least one side

4. A threaded cap according to one of the preceding claims, characterized also because the sectors of Said edge which are intermediate to said flaps have smaller cross sections than the flaps.