DE69401275T2 - ORIGINAL CLOSURE FOR PLASTIC CONTAINERS - Google Patents

Description

The invention relates to a tamper-evident closure for plastic containers with the features of the preamble of patent claim 1.

Tamper-evident closures of the type described are known per se and are particularly suitable for containers with a substantially rectangular or polygonal shape. The known closures comprise one or more pairs of connecting elements, for example pin-shaped elements with arrow-shaped tips, which can be inserted into the complementarily shaped elastic recesses formed along the edges of the lid and the container or the corners of the container. These connecting elements are intended to cooperate unidirectionally when closing the container, so that it is necessary to destroy them when opening the lid, that is to say to separate them from the corresponding area of the container or lid by levering between them or by operating the handle wings provided for this purpose.

The possible shapes of the container are limited by the arrangement of these traditional closures at the corners. Containers with a round shape, for example, must be provided with a series of radial wings on which the closures are formed, resulting in higher manufacturing costs and a greater mass of the manufactured products.

Furthermore, with this type of closure, the connecting force is only applied locally and is therefore not evenly distributed along the edges.

Another disadvantage of traditional tamper-evident closures is the fact that in order to obtain strong elements and due to their relative complexity, the lid and the container must be manufactured by injection molding processes, thus preventing the use of molding thermoplastic materials.

Furthermore, with the known type of closures, one of the connecting elements can remain loose on the corresponding edge after opening and can accidentally fall into the interior of the container.

Furthermore, in many cases it is not possible to detect that the seal has been opened, so that the consumer has no positive assurance about the integrity of the packaging.

From FR-A-2437987 a plastic container with a closure having the features of the preamble of claim 1 is known, wherein a series of openings are formed in a strip with a weakened connection line in the area of the connection with the edge of the lid. Tearing of the strip along the weakened line is often unsafe since the resistance of the cross-sectional areas is difficult to control.

From EP-A-0121172 a correspondingly fragile closure for plastic containers is known, wherein one of the connecting elements is attached to the edge of the lid with one or more weakened lines, the tearing of which is unreliable and not obvious.

The aim of the present invention is to avoid the above-mentioned disadvantages by providing an original closure that can be opened in a reliable and obvious manner and applied to containers of any shape without modifying the external profiles of the container or the lid.

It is an object of the present invention to provide a tamper-evident closure which can be produced in the same way, regardless of whether it is a process for forming thermoplastic materials or is an injection molding process using molten plastic materials to achieve production advantages.

A further object of the invention is to provide a tamper-evident closure that extends along the entire circumference of the lid and must be completely removed to enable the container to be opened.

This aim as well as these and other objects of the invention are achieved by a tamper-evident closure for plastic containers with the features of patent claim 1.

With the arrangement according to the invention, the closure can be applied to containers of any shape, for example with a round shape, without having to change the external profile of the container or the lid, since it is not necessary to use a corner or a projection of the edges in order to be able to arrange the connecting elements, thus achieving the main aim of the invention.

Furthermore, the connecting elements are arranged along the entire circumference of the closure edges, which results in greater security of a hermetic closure.

Finally, any damage to the closure is clearly visible from the outside due to the arrangement of the connecting elements on the outer periphery, thereby achieving one of the objects of the invention.

According to the invention, first connecting elements or engaging units can be formed by a series of projections which are substantially radial with respect to the outer peripheral region of the edge on which they are formed.

Preferably, the projections consist of a plurality of teeth which are slightly outwardly rising and approximately trapezoidal in shape, with the longer parallel side directed inwards, and which are monolithically with respect to the outer peripheral region at equiangular spacing positions along the extent.

Second engagement means are formed by a series of openings which are substantially parallel to the outer peripheral region of the edge on which they are arranged.

According to the invention, the openings are formed by a strip of material, which is connected to the corresponding edge by a series of transverse wings, which are at least equal in height to the maximum thickness of the projections, and in respect of the same angular spacing positions corresponding to those of the projections.

According to the invention, the wings taper upwards in the area where they are arranged on the outer peripheral area of the corresponding edge, and the connection area has a narrower tear resistance cross-section than the area for connection to the strip.

Advantageously, the strip may comprise a substantially radial handle with a cross-section at least equal to the maximum cross-section of the wings, and a transverse cam in a position adjacent to a lateral corner of the handle so as to form a predetermined breaking point and to cause initiation of the breaking of the strip to enable the subsequent separation of the wings from the peripheral region of the edge on which they are arranged.

According to the embodiment of the closure according to claim 1, both the container and the lid can be formed from plastic using either an injection molding process or a compression molding process, whereby the same mechanical strength of conventional closures is ensured at considerably lower costs, thereby achieving a specific object of the invention.

Further advantages and features of the invention will become apparent from the following detailed description of an exemplary and non-limiting

Embodiment of a closure according to the invention, which is described using the accompanying drawings, in which:

Figure 1 is a front view and partially sectioned view of a container and a lid with a tamper-evident closure according to the invention before closing;

Figure 2 is an enlarged front view of a detail according to Figure 1, with the container closed;

Figure 3 is a sectional view of the detail according to Figure 2 along the line IIIIII; and

Figure 4 is a sectional view of a detail according to Figure 3 along the line IVIV.

The container for food or other commercial products shown in the figures is generally designated by the reference numeral 1. The container comprises a lid 2 with a substantially flat central wall 4 and a receptacle 3 with a side wall 5 and a bottom wall 6. Both the lid and the container may be made of plastic, for example polyethylene, polypropylene, PVC or other equivalent materials which may be manufactured by injection molding or molding of preheated material.

The lid 2 has a folded edge 7 with an outer peripheral region 8 which is approximately vertical, or better slightly inclined at about 10º to allow expansion, and is connected to an inner peripheral region 9 by an annular region 10 which is approximately flat or horizontal.

The receptacle 3 has a folded edge 11 with an outer peripheral region 12 which is also inclined by approximately 10º and is arranged on the side wall 5 by an annular region 13 which is approximately flat and slightly inclined with respect to the horizontal.

The edges 7 and 11 are essentially complementarily shaped in order to enable a sealing connection mainly along their respective inner and outer peripheral regions even after a first opening.

According to the invention, an engagement device is formed along the outer peripheral region 8 and 12 of the edges 7 and 11 and is suitable for being elastically and unidirectionally connected by pressure in order to hermetically close and seal the container.

In particular, along the outer periphery 12 of the container, a series of projections or teeth 14 are formed, extending radially and rising outwardly approximately 40° with respect to the peripheral region 12. The projections may be approximately trapezoidal in shape, with the longer parallel side disposed at the peripheral region 12, with a predetermined height S and a width L.

Along the peripheral region 8 of the edge of the container there is a series of openings or slots 15 arranged at equal angular intervals corresponding to those of the projections 14.

The openings 15 result from the connection between a strip 16, which runs continuously along the circumference, and transverse wings 17, which connect the strip 16 to the peripheral region 8.

The wings 17 have an approximately pyramidal shape which tapers upwards and includes upper and lower connecting regions 18 and 19. The resulting openings 15 are elongated in a direction substantially parallel to the peripheral region 8 and have a maximum width W in the upper connecting region 18 of the wings to the peripheral region 8 and a minimum width W in lower connecting regions 19 of the wings to the strip 16. The resulting cross-section of the connecting regions 18 is relatively smaller than that of the regions 19. The minimum width W of the openings 15 between the base of the wings 17 is greater than the width L of the projections 14.

After filling the container, the packer moves the lid closer and pushes it towards the container so as to align the projections 14 with the openings 15, thereby locking the projections in the openings. The lid cannot be lifted due to the negative fit of the upper edge 16' of the strip 16 against the base of the teeth 14.

In the embodiment, a gripping tab 20 is arranged on the strip 16 for gripping the part by a user. As shown in particular in Figure 4, the strip has a wedge-shaped groove or tear 21 at one of the corners of the gripping tab 20, which forms a stress increaser of the strip.

A consumer can recognize that the container is closed by the presence of the strip 16. When the consumer wishes to open the container, the gripping tab 20 can be grasped and pulled up and down, causing the strip to break at the groove 21. As the pulling force continues, the consumer separates the strip from the outer peripheral region 8 at the connecting region 18, which has a resistive cross section. In this way, the lid is released and can be opened.

In the following use, as already mentioned, the sealing is in any case ensured by the contact of the opposite surfaces of the inner and outer peripheral areas of the complementary edges.

The closure according to the invention achieves the intended aim and solves the objectives, and in particular it should be noted that it can be applied to containers of any shape, even if there are no corners. Furthermore, it can be manufactured by molding thermoplastics or equally by injection.

To the extent that technical features in the claims are provided with reference signs, such reference signs have been introduced only to improve the comprehensibility of the claims and thus have no limiting effect on the spectrum of each element mentioned by way of example by the reference signs.

Summary:

A tamper-evident seal for plastic containers comprising a receptacle and a lid (2) with a flat wall (4). The receptacle and the lid have respective complementarily shaped edges (7; 11) with outer peripheral regions (8; 12) which are substantially vertical or slightly inclined. Projections (14) are arranged along the outer peripheral region (12) of one of the edges and are suitably provided for elastic and unidirectional connection by pressure with slots (15) arranged along the outer peripheral region (8) of the other edge. The projections (14) are substantially radial with respect to the outer peripheral region (12) of the edge on which they are formed and are shaped like teeth with a slight outward inclination. The openings (15) are substantially parallel to the outer peripheral region (8).

Claims (9)

1. Tamper-evident device for plastic containers with a receptacle (3) with side (5) and base surfaces (6), and with a lid (2) with a substantially flat wall element (4), the receptacle (3) and the lid (2) having correspondingly complementary shaped edges (7, 11) with outer peripheral areas (8, 12) which are substantially vertical or slightly inclined, the security comprising first engagement units (14) consisting of a row of substantially radial projections (14) along one (11) of the edges, and second engagement units (15) consisting of a row of openings (15) along the other (7) of the edges, the projections (14) being in precise alignment with the openings (15) along the corresponding edges (7, 11) on which they are formed with regularly spaced positions along the entire extent of the edge (7, 11). wherein the first and second engagement units (14, 15) are complementarily shaped and designed for resilient and unidirectional mutual connection by snap-fitting to provide a securing means to the lid (2) and the receptacle, wherein the openings (15) are formed by the connection of a continuous strip (16) of plastics material and a series of regularly spaced wing elements (17) which fix the strip (16) to the corresponding edge (7) in a spaced position, the height (H) of the wing elements (17) from the edge (7) being at least equal to the height (S) of the projections (14), characterized by that the wing elements (17) are tapered upwards in the direction of the connection area (18) with the corresponding edge (7) in order to define a smaller tear resistance cross-section of the wing elements (17) in this area than in the area of the connection (19) of the wing elements (17) with the strip (16). 2. A fuse according to claim 1, characterized in that the protrusions (14) consist of a plurality of teeth which are formed monolithically with the corresponding outer peripheral region (12). 3. A fuse according to claim 2, characterized in that the teeth are slightly inclined outwardly with respect to the outer peripheral region (12) on which they are formed and have a predetermined width (L) and a cross section which is formed approximately trapezoidally, the longer base being formed on the outer peripheral region (12) and having a length which corresponds to the height (5) of the projections (14). 4. A safety device according to claim 3, characterized in that the openings (15) are elongated in a direction substantially parallel to the outer peripheral region (8) of the corresponding edge (11) and have a length (W) which is equal to or greater than the width (L) of the teeth. 5. Safety device according to claim 1, characterized in that the strip (16) has a gripping lug 20 which has a transverse cross section that is at least equal to the cross section of the wing elements (17) in the region of the connection (19) with the strip (16). 6. A fuse according to claim 5, characterized in that the strip has a transverse groove (21) in a position adjacent to a side edge of the gripping tab (20) so as to form a weakened zone to provide separation of the wing elements (17) from the peripheral region of the edge to which they are connected. 7. Fuse according to claim 1, characterized in that the edges (7, 11) have a substantially U-shaped cross-section, the projections (14), the wing elements (17) and the strip (16) being formed in one piece with the respective edge of the lid (2) and the receiving container (3) by injection molding or the molding of semi-finished plastic products. 8. Fuse according to claim 1, characterized in that the projections (14) and the opening (15) are formed correspondingly along the edge of the lid (2) and the container (3). 9. Fuse according to claim 1, characterized in that the projections (14) and the openings (15) are formed correspondingly along the edge of the receiving container (3) and the lid (2).