EP0001959B1 - Tamperproof device for container with a neck closed by a threaded cap and process for the first opening of the container - Google Patents

Description

The object of the invention is a tamper-evident device for a container, the neck of which is closed by a screw cap. Another object of the invention is a method for carrying out the first opening of the container.

Various tamper-evident devices are known guaranteeing the consumer that the container he is buying has not been fraudulently opened, that the content has not been polluted or even withdrawn and replaced by a worthless product.

Flexible tubes are known, the plastic neck of which is closed by a plug incorporated in the form of a blind tube. The open end of the blind tube is connected to the end of the neck by a zone of less resistance which can easily be torn off by twisting. The closed end of the blind tube has an outside diameter corresponding to the inside diameter of the opening made at the end of the neck by rupture of the blind tube. It is thus possible to close the neck temporarily by turning the cap upside down and pushing the closed end of the blind tube, as shown in French patent No. 1,181,592.

However, this plugging is not fully satisfactory because the forced insertion of the end of the blind tube into the neck constitutes a very rudimentary method of assembly.

In addition, the end of the plug could have been polluted by uncontrollable contacts.

Capsules are also known which are screwed with a frangible peripheral band or flange along a line of least resistance.

Tamper-evident devices are known which consist of a thin aluminum seal glued to the opening of the neck. This cover must be torn off or fractured before withdrawing the contained product. This device has the disadvantage of poor visualization.

It requires unscrewing the protective cap and carefully examining the seal to check the condition of the seal. It obliges the container manufacturer to carry out an additional operation of placing and gluing the thin seal before screwing on the cap.

Thin plastic lids are known which are made in one piece with the neck also made of plastic, but it is not possible to obtain plastic lids of very precise thickness, and therefore always of sufficiently small thickness. Plastics are elastic materials, not very malleable. opening such covers requires a tool.

The patent US Pat. No. 3,784,045 is also known. It describes a plastic neck closed by a nozzle which extends it by being connected to it by a circular zone of lesser resistance. The opening of the container is done by sectioning this zone of least resistance, this sectioning is easily done by screwing on the neck of a ring which is provided either with a cutting blade or with 2 threads of different pitches and corresponding respectively one to that of the nozzle, the other to that of the neck. After cutting, the end piece remains attached to the ring, which allows the neck to be filled after the first use.

This device does not, however, allow a truly sealed filling of the neck, this because the end piece is not firmly locked in the ring or at the bottom of the capsule which can take its place. A harmful space may remain at the bottom of the capsule.

The object of the present invention is a new tamper-evident device constituted by a neck closed by a screwed cap, but initially closed by an end piece in the form of a blind tube which extends the neck. From the first opening, this tip is positively blocked at the bottom of the closure capsule. It now functions as a seal without the product can ever come into contact with the capsule which may not be as aseptic as it would be desirable.

In this device, the open end of the blind tube is connected to the end of the neck by a weakened area. This weakened area has an outer diameter smaller than that of the blind tube. The blind tube is threaded according to a thread of the same axis and not the same as the thread of the neck, the threads of the blind tube corresponding to those of the neck, so that the neck and capsule are screwed at the same time in a double-tapped capsule. For this, the capsule, in addition to its main thread complementary to the thread of the neck, has an auxiliary thread of the same axis and not even (p) complementary to the thread of the blind tube. The distance between the bottom of the auxiliary thread of the capsule and the lower end of its main thread is less than the distance between the end of the blind tube and the bottom of the main thread of the neck while the depth of the auxiliary thread is less than the height of the blind tube. Thus, when the capsule is screwed simultaneously onto the blind tube and the neck, it is the bottom of the auxiliary thread of the capsule which first abuts on the closed end of the blind tube, before the screwing of the capsule on the neck is not total. The blind tube is then blocked at the bottom of the capsule. If the screwing is continued, the blind tube is driven by the capsule and sinks into the neck with a helical movement. The weakened zone connecting the blind tube to the end of the neck breaks quickly by shearing: it suffices to continue screwing for about 1/3 of a turn. To ensure easy rupture, the weakened zone of the blind tube is generally given a thickness about 1/3 of that of the wall of the blind tube. This weakened zone corresponds to a peripheral groove reducing the thickness of material at the connection of the blind tube with the neck. The outside diameter of the weakened zone is thus less than the diameter of the tube, which allows it to penetrate slightly into the neck during the driving-in / shearing operation when the cap is continued to be screwed.

The object of the invention is therefore also a method for the first opening of a container provided with an aforementioned tamper-evident device according to which the blind tube is blocked by screwing in the bottom of the capsule and which is broken the area weakened by twisting and sinking into the neck.

The maximum distance between the bottom of the auxiliary thread and the bottom of the main thread of the capsule can vary depending on the elasticity and brittleness of the materials. It is generally at least half a thread pitch less than the distance between the end of the blind tube and the bottom of the main thread of the neck. This allows a screwing of at least 1/2 turn after the bottom of the capsule has abutted on the end of the blind tube. The depth of the auxiliary tapping of the capsule must also be at least 1/2 pitch less than the height of the blind tube so that the bottom of the auxiliary thread does not come up against the end of the neck.

The diameter of the blind tube is generally of the order of half the diameter of the neck.

Such devices are easily produced in various plastics such as P.C.V., polyethylene, polypropylene; they are particularly suitable for making flexible metal or plastic tube heads.

The invention will be better understood from the following description of a particular example, as well as from the accompanying drawing.

The accompanying drawing shows, in axial section, a flexible polyethylene tube head mounted by snap-fitting or by force on a flexible tube body (1) made of aluminum.

The head of the flexible tube (1) has at its upper part a threaded neck (2) of conventional shape intended to be closed by a screw cap (3) or by means of a tapping (4).

The neck (2) of the head is extended by a blind tube (5) the outside of which is threaded with a thread with a diameter smaller than that of the neck (2), but similarly and whose threads are in agreement. The base of this blind tube (5) is connected to the end of the neck (2) by a weakened zone (6) of reduced diameter, this both with respect to the outside diameter (D) of the neck (2) and to the diameter (d) of the blind tube (5). This reduction in diameter corresponds to a peripheral groove at the connection of the blind tube (5) with the neck (2) leaving the weakened area a thickness (e).

The capsule (3) itself comprises two complementary coaxial threads each with a thread of the head. The main thread (4) of the capsule allows it to be screwed onto the neck (2). The auxiliary thread (7) has a diameter (d) corresponding to that of the thread of the blind tube (5); its depth (1) is less than the height (h) of the blind tube (5). The diameter (D) of the main thread (4) corresponds to that of the neck thread. The distance (L) between the bottom (8) of the auxiliary thread (7) and the bottom of the main thread (4) is less than the distance (H) between the end of the blind tube (5) and the bottom (9) the main thread of the neck (2). Thus, during the first screwing of the capsule (3) on the head of the flexible tube before use of the content, the two threads (4 and 7) of the same pitch, and whose threads correspond, are simultaneously screwed onto the neck (2 ) and the blind tube (5). The end of the blind tube (5) abuts first on the bottom (8) of the auxiliary thread (7) before fully screwing the capsule to the bottom (9) of the neck (2). It is only important, during this first screwing, to exert a limited force so that the screwing stops without forcing as soon as the bottom (8) of the auxiliary tapping abuts on the end of the blind tube (5).

To make a perforation in the neck and to be able to use the contents of the container, the screwing is slightly forced; it can continue on the neck (2) by the thread (4) but not on the tube (5) which abuts on the bottom (8). The tube (5) is driven by the helical displacement of the capsule (3), which continues to be screwed onto the neck (2). The weakened zone (6) sinks slightly into the end of the neck (2) by bending and undergoing a torsional force. The weakened zone (6) is easily broken by shearing without having to continue screwing more than about 1/3 of a turn, thus creating the desired perforation at the end of the neck (2).

It is easily understood that, for this operation to be possible, it is important that the capsule (3) in this screwing does not come up against the bottom (9) of the main thread of the neck (2) nor on the end of the neck itself- even before the weakened area (6) has undergone sufficient torsional-shear stress. More simply, it is important to have simultaneously H> L and h> 1. In practice, we will generally take HL = hI with HL>

It is also understood that if the capsule (3), for reasons of aesthetics or ease of stacking, comprises a skirt (10) of the same outside diameter as the flexible tube (1), it is important to provide a clearance (E) between the bottom of the skirt and the shoulder of the flexible tube. We must have substantially: E = H - L.

Thus, the use of this device is particularly easy. The capsule (3) is simultaneously screwed onto the neck (2) and the blind tube (5) until the end of the blind tube (5) abuts without forcing on the bottom (8) of the auxiliary thread (7) .

The head of the tube with its capsule (3), in place is mounted on the flexible tube (1). The tube (1) is filled from below with consumable product. According to the usual process with flexible tubes, the bottom of the tube (1) is sealed immediately after filling and the full tube sent to a distributor. It is easy to see from the distributor that the tube has not been fraudulently opened by simply checking the clearance (E) between skirt (10) and tube head or the clearance (H - L) between the bottom of the main thread ( 4) of the capsule and the bottom (9) of the main thread of the neck, without even having to completely unscrew the capsule. The capsule can also be completely unscrewed without in any way damaging the tamper-evident device.

When the consumer wants to use the content, it forces the screwing of the capsule (3) by about 1/3 of a turn. The weakened area (6) breaks easily. Then unscrewing the capsule (3), the blind tube (5) remains blocked against the bottom of the capsule. During subsequent fillings, the base of the blind tube (5) at the level of the weakened zone (6) will become a seal on the neck. The base of the blind tube (5) could not have been polluted by any external element.

In the example shown, the head of the flexible tube, with its neck (2) and its blind tube (5) are made of polypropylene as well as the capsule (3). The tube (1) is made of aluminum.

The dimensions of the elements of the head of the tube are substantially as follows:

The tube (1) could equally well be made of plastic or of a metallo-plastic complex.

Claims (7)

1. An inviolability device for a container having its neck closed by a screw cap, the orifice of this neck initially being blocked by a blind tube having an external screw thread, the open end of which is connected to the end of the neck by a weakened zone having a diameter which is smaller than that of the blind tube while the cap comprises a double tapping, one of which complements the screw thread of the neck and the other of which complements the screw thread of the blind tube, characterised in that the two tappings h we the same axis and the same pitch p and that their threads are in harmony, thus allowing them to be screwed simultaneously, in that the balance L between the bottom 8 of the auxiliary tapping 7 and the base of the main tapping 4 is smaller than the distance H between the end of the blind tube and the base 9 of the main screw thread 4 of the neck, while the depth 1 of the auxiliary tapping is smaller than the height h of the blind tube 5, the cap 3 screwing simultaneously on to the neck 2 and the blind tube 5 butting first with the bottom 8 of its auxiliary tapping against the closed end of the blind tube 5.

2. A device according to any one of claims 1 or 2, characterised in that the values H-L and h-I are each at least equal to

3. A device according to any one of claims 1 or 2, characterised in that the external diameter d of the blind tube is substantially equal to half the diameter D of the neck.

4. A device according to any one of claims 1, 2 or 3, characterised in that the neck of the container and the cap are made of plastic material such a polypropylene, polytheylene, PVC.

5. A device according to any one of claims 1, 2, 3 or 4, characterised in that the neck of the container is a plastic head which is forcefully ratched or fixed on a metal tube 1.

6. A device according to any one of claims 1, 2, 3, 4 or 5, characterised in that the neck of the container is a plastic head which is moulded or welded on to a flexible tube body made of plastic material or of a metallo-plastic complex.

7. A process for the first opening of a container provided with an inviolability device according to one of claims 1 to 6, characterised in that the blind tube 5 is blocked by screwing in the bottom of the cap 3 and the weakened zone 6 is broken by torsion and by driving into the neck 2.

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