Abstract:
A security ring device to determine whether a container has been opened is integrated with a container and its cover. The security ring device has a rim which abuts the depending edge of the skirt of a container cover. The interior of the skirt has a portion which is provided with a perimeter groove. At least two lugs extend from the rim to the groove to lock the ring to the skirt. At least one lug extends from the rim to the container which has an outwardly extending flange portion positioned so that upon turning the cover to open the container, the at least one lug which extends from the rim to the container and establishes a tension for breaking the ring member. A collar may extend from the rim and abut the outer wall of the skirt. At least one weakened zone may be positioned in the rim ring to facilitate breaking.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to security rings for screw-threaded and snap-on closures for indicating whether a container has been opened. 
     Systems by which it is possible to see whether a pack has already been opened are well known. PCT Patent Application Publication No. WO 91/01925 relates to a closure for wide-necked containers comprising a cover with a security ring, the closure being mounted on the neck of the container. The principle of this tamper-proof closure system is based on the fact that, when the container is opened, the enlargement of the skirt of the closure cover deforms the security ring integral with the skirt which thus breaks at weakened points. This system offers a simple and safe way of telling whether a container has been opened. The disadvantage of this system is that it is designed for square Jars in which the security ring is broken by the deformation of the skirt of the cover. In the case of a round jar, there are no unlocking lugs on the neck of the container to deform the skirt of the cover. Accordingly, a solution based on a different principle has to be found. 
     SUMMARY OF THE INVENTION 
     The problem addressed by the present invention was to provide a system for visually showing whether a container with a screw cover or snap-on cover has been opened. 
     The present invention provides a security ring used for a closure comprising a rim with at least one locking lug and at least two detent lugs, and it may comprise a collar integral with the rim. 
     The advantage of the closure system according to the invention is that it enables already existing containers and covers to be retained. It is merely necessary to make the security ring which is then fitted to the cover. Since the container itself is filled and capped, all that remains is to place the closure system according to the invention on top of the container. 
     The device according to the invention may be used with particular advantage for containers of instant coffee, milk powder and other food products. 
     Thus, the present invention also relates to a screw-threaded closure for containers comprising a security ring integral with a cover designed to be fixed to the neck of the container, the cover comprising a base and a lateral skirt of which the inner wall comprises closure ramps forming a screwthread and designed to cooperate with corresponding closure ramps disposed on the outer part of the neck of the container, in which the security ring comprises a lower rim bearing against the lower edge of the skirt of the cover and comprising at least one locking lug and at least two detent lugs, the locking lug--in the closed position of the cover--bearing against a flange of the neck of the container situated beneath the closure ramps and the detent lugs being locked in a circular groove formed in the lower inner part of the skirt of the cover. 
     The present invention also relates to a snap-on closure for containers comprising a security ring integral with a cover designed to be fixed to the neck of the container, the cover comprising a base and a lateral skirt of which the inner wall comprises coupling means designed to cooperate with a flange on the outside of the neck of the container, in which the security ring comprises a lower rim bearing against the lower edge of the skirt of the cover and comprising at least one locking lug and at least two detent lugs, the locking lug--in the closed position of the cover--bearing against the flange on the outside of the neck of the container and the detent lugs being locked onto a serration provided in the lower inner part of the skirt of the cover. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the screw-on embodiment, the cover is preferably round and cooperates with a round neck, and in the snap-on embodiment, the cover is advantageously square in shape while the neck of the container is round. 
     In the screw-on embodiment, the skirt of the cover is not deformed when the cover is opened. The principle is based on the vertical displacement of the cover. When the container is opened, the locking lug bearing against the flange of the neck of the container fixed to it abuts against the flange. On the other hand, since the detent lug is locked onto the bottom of the skirt of the cover, it moves upwards with the cover, this vertical displacement of the cover creating a tension between the locking and detent lugs, which results in breakage of the security ring if the cover is removed from the container. 
     In one particular embodiment, the security ring comprises a collar integral with the rim and following the shape of the lower outer wall of the skirt of the cover. This collar enables the ring to be made more secure during handling. 
     In the snap-on embodiment, there is no collar because the ring does not have to deform when the cover is positioned on the container. By contrast, tension can be established in the ring during the upward movement of the cover at the moment of opening. The security ring preferably has two locking lugs and two detent lugs. 
     The security ring is in one piece and may be made by injection molding from a breakable material preferably based on polystyrene. 
     The cover is made separately from the security ring. 
     The configuration of the ring is such that the rings can be stacked which enables space to be saved. The rings may be supplied either individually or already mounted on the cover. 
     In the screw-on embodiment, a gap has to be provided on the inside of the skirt to create a sufficient space for the thickness of the locking and detent lugs when the cover is screwed onto the container. 
     When the container is opened, the security ring breaks and the fragments separate cleanly towards the outside. Accordingly, this affords the advantage that, after the initial opening, the ring is no longer on the container so that a conventional pack is formed. 
     The container is preferably made of glass with various neck diameters. The cover is a conventional cover comprising, for example, four locking ramps corresponding to the four ramps provided on the flange of the container. The cover is preferably made of polyethylene or polypropylene. The inner part of the base of the cover comprises a cardboard slip, a foam slip (expanded polyethylene) weldable by induction, a sealing ring applied in paste-like form which polymerizes in the ambient air or a barrier foam. 
     If the security ring with its collar is vertically cut, an L-shape is formed, the vertical part of the L being the collar of the ring which follows the shape of the lower outer wall of the skirt of the cover. 
     The locking and detent lugs are integral with the lower rim of the security ring, the lugs projecting obliquely towards the inside of the cover and towards to top of the container. 
     The above-mentioned lugs are in the form of small tongues with openings for reasons of elasticity, the locking tongue normally being longer than the detent tongue. The length of the locking tongue is determined by the distance separating the bottom of the skirt of the cover from the flange of the neck of the container. 
     The number of locking and detent lugs is crucial to the clean breakage of the security ring. Each security ring preferably has three each of these lugs. It is obvious that the lugs are normally distributed around the circumference of the ring in an alternating sequence, i.e., a locking lug, a detent lug, a locking lug and so on. However, this arrangement is not essential to establish the necessary breaking tension in the ring. If the lugs are uniformly distributed with three locking lugs, the locking lugs form an angle of 120° between one another in one and the same plane in the same way as the detent lugs. 
     Configurations with three locking lugs and three detent lugs are also possible and further facilitate breakage of the ring during opening of the container. 
     To ensure that the ring breaks between the above-mentioned lugs, it is preferable to provide weakened zones in the ring. These weakened zones may be formed by slots, for example U-shaped or V-shaped slots, their function being to establish around the periphery of the ring zones of reduced thickness or zones of reduced width with predetermined breakage zones. 
     In a first embodiment, the security ring comprises between each locking and detent lug at least one slot forming a weakened zone for the ring, the locking lug being formed by a single tongue. 
     In a second embodiment, each locking lug is formed by two tongues, a weakened zone being provided between the tongues. 
     The detent lugs each comprise a retaining catch which engages in the circular groove formed in the inner lower part of the skirt of the cover. This ensures total locking of the security ring on the cover. 
     The invention is described in detail in the following with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of the security ring. 
     FIG. 2 is a partial section through the screw cover for the closure of the container. 
     FIG. 3 diagrammatically illustrates the closure according to the invention mounted on a container. 
     FIG. 4 is a section through part of FIG. 3. 
     FIG. 5 is a section through the security ring on the line 5--5 of FIG. 1 showing the weakened zone. 
     FIG. 6 is a plan view of the security ring in a second embodiment. 
     FIG. 7 is a plan view of the security ring in a third embodiment. 
     FIG. 8 is a plan view of the security ring for a container with a snap-on cover. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     As illustrated in FIG. 1, the security ring (1) comprises a collar (2) and a lower rim (3). The locking lugs (4) and the detent lugs (5) are integral with the lower rim. These lugs each comprise openings (6) and (7) so that they are highly elastic. The weakened zones (8) are positioned between the locking lugs and the detent lugs. The ring is made of polystyrene. 
     FIG. 2 is a partial section through the container cover. The cover (9) comprises a base (10) and a lateral skirt (11). The inner part of the base of the cover comprises a zone (12) for accommodating a slip (not shown) which is held in place by means of the circular groove (13). The inner part of the lateral skirt comprises closure ramps (14) and a circular groove (15). 
     FIGS. 3 and 4 show the combination of the elements illustrated in FIGS. 1 and 2. The container (16) to be closed comprises a neck (17) onto which the cover (9) integral with the security ring (1) is screwed. In the closed position of the container, the closure ramps (14) of the cover cooperate with corresponding closure ramps (18) of the neck of the container (16). The slip (19) in the cover bears against the upper flange of the neck of the container. The security ring (1) is locked onto the skirt of the cover by means of the detent lugs (5) comprising retaining tongues (20) which engage in the circular groove (15) of the skirt of the cover. The locking lugs (4) of the ring abut against a flange (21) of the neck of the container. 
     As will be noted from FIGS. 3 and 4, and with reference to FIGS. 1 and 3, the rim (3) has a surface which abuts the skirt edge (9a) and defines a rim width. Detent lugs (5), which terminate in the integral tongue (20) are integral with and extend from another surface of the ring rim (3), which defines a rim thickness, to project into cover groove (15) so that the lug (5) and its tongue (20) and the rim (3) abut the cover edge (9a) and groove (15). Locking lug (4) extends from the rim (3) to project towards the container so that upon turning the cover to open the container, lug (4) is restrained by flange (21) to establish a tension for breaking the ring member. As illustrated, lug (4) extends obliquely from the rim (3) to form an obtuse angle with respect to the rim surface adjacent cover edge (9a). As also illustrated, the collar (2) extends from the rim (3) transversely with respect to the rim surface adjacent cover edge (9a) so that spaces are formed between the collar and lugs and thus form a U-like shape. 
     When the container is opened, the cover (9) is unscrewed, moving upwards in the process. Since the detent lug (5) is completely locked onto the skirt of the cover and since the locking lug (4) presses against the flange (21), tension is established around the circumference of the security ring between each locking lug and detent lug. In the ring shown in FIG. 1, for example, there are six tension zones. 
     Slots (8) (FIGS. 1 and 5) are provided in these zones, for example in the middle thereof. In the present case, six slots form zones of reduced thickness in the security ring at these places. The more the cover is lifted or unscrewed, the more the tension increases until ultimately the ring breaks in these weakened zones. In the present case, the slots are U-shaped. The system as a whole provided in this way makes it possible to tell safely whether the container has been opened. This is because, if the ring has really been broken, there is often a ring fragment which will have disappeared so that the consumer will be in a position to tell immediately whether the container has been opened. 
     The only differences between the security ring (23) shown in FIG. 6 and that shown in FIG. 1 lies in the locking lugs (24) which, in this case, are formed by two identical tongues (25), the weakened zone (26) being situated between these two tongues and no longer between the locking and detent lugs. The other elements are denoted by the same reference numerals. The security ring will undergo the same tensions for the same reasons as before, except that it will break at the three weakened points (26). 
     The only difference between FIG. 7 and FIG. 6 is that the security ring does not have a collar. However, the ring is designed to break in the same way as the ring shown in FIG. 6 at (26). 
     FIG. 8 shows a security ring (30) for a snap-on cover. In the same way as the screw covers, it comprises a lower rim (31) bearing locking lugs (32) formed by two identical tongues (33) and detent lugs (34). The weakened zone (35) is situated between the two tongues. The only difference between FIG. 8 and FIG. 7 lies in the geometric shape of the security ring which is round for the screw cover and square for the snap-on cover.