1. Field of the Invention
The invention relates to container and its screw sealing cap and tearoff security strip and more particularly relates to an improvement to the sealing, plugging or stopping of containers having a constricted threaded zone making it possible to screw down a cap provided with its security strip.
2. Description of Related Art
Numerous tamper-proof containers already exist which have a threaded ring and are scaled by the screwing down of a cap.
As shown in FIG. 1A, one known way of ensuring inviolability consists of using on the one hand an internally threaded scaling cap (2A) which is provided with a security strip (3A) joined to the cap by bridges (13A) and which is provided on its inner face with ratchet notches (14A) and on the other hand a container (1A) provided in its constricted part or neck (6A) a portion (9A) with ratchet teeth (10A) in addition to a threaded portion (8A). On sealing the container, before or after the conditioning phase as a function of the nature of the container, tube or bottle, the cap is screwed onto the container neck and the ratchet notches and teeth ratch in such a way as to permit screwing down and so as to prevent the unscrewing of the cap, except after the security strip has been torn off.
The applicant has manufactured containers and their sealing cap with a security strip in accordance with the prior art, more particularly plastic tubes such as those defined in Example 1 and has encountered difficulties during the sealing thereof.
The problem is that there is a breaking of the bridges (13A) connecting the cap body (16A) and the security strip (3A) during the screwing down of the cap before filling the tube. Thus, the Applicant has observed a high breaking rate which can reach 20%, which makes the container industrially unusable. The Applicant has also observed the presence of tubes which were no longer tamper-proof, because it was possible to unscrew the cap without breaking the bridges, which is obviously unacceptable.
In order to solve this problem, the Applicant has attempted to reduce the ratcheting, i.e. the interpenetration of the teeth (10A) and the notches (14A) but, although there was then a reduction in the breaking rate, there was also an increase in the number of tubes which were no longer tamper-proof. Therefore this solution was abandoned.
In industrial production, the characteristic parameters and in particular the geometrical dimensions have a certain tolerance including, inter alia, the machining precision of the production tools, their wear prior to replacement, etc., so that there can be a certain variation in the quality of the goods produced, which is normal but not desirable. In the case of the production of the tubes of Example 1, the final quality is too sensitive to the normal variations of the production parameters, because in the same production batch there are both satisfactory tubes, tubes with broken bridges and tubes which are not tamper-proof, so that this type of tube is not industrially acceptable.
Consideration has also been given to reinforcing the bridge, but this leads to making the opening more difficult. Opening should involve a manual tearing away of the security strip without exerting any particular force and without using tools such as pliers. Therefore this solution was also unacceptable.