EP0506784B1 - Seal for detection of access to an object - Google Patents

Abstract

The invention relates to a seal for detection of the access to an object or a relative motion between a plurality of juxtaposed objects. According to the invention, the seal is comprised of an envelope (1) with dimensional recovery arranged to cover at least partially the object or objects (21, 22) and presenting, at least after dimensional recovery, weakening areas (4). Application particularly to the covering of fluid conduit adaptors, electric or optical cable connectors, threaded mouthpieces for compressed gas bottles, and to the covering of cases.

Description

The invention relates to a seal intended to detect access to an object or a relative movement between several juxtaposed objects.

• les fils plombés nécessitent une installation longue et délicate, surtout dans les endroits sombres et difficiles d'accès. Ils nécessitent des points d'ancrage prévus spécialement pour leur utilisation, et leur structure hétérogène fait qu'il est facile de repérer leurs points faibles et relativement facile à une personne non autorisée de les démonter et remonter en laissant le minimum de traces. De plus, les matériaux utilisés se ternissent rapidement au contact de l'atmosphère ou de produits chimiques, effaçant rapidement les éventuelles traces résultant du démontage et du remontage du plomb ;
• les cires et vernis sont aisés à se procurer et il est donc facile à toute personne de reconstituer le scellé d'origine, sauf dans le cas de l'utilisation d'un graphisme bien spécial, mais cela réduit alors l'utilisation à des surfaces planes ;
• les systèmes à demi-coquilles encliquetées offrent, de par leur structure (présence de charnières et d'un système d'encliquetage, jeu important par rapport au substrat), plusieurs possibilités d'accès à l'utilisateur non autorisé, qu'il est aisé de repérer. De ce fait, ces systèmes sont faciles à frauder sans laisser de traces ou en ne laissant que des traces difficiles à détecter dans les conditions dues à l'environnement d'utilisation du matériel.

There are already many models of "seals" but these have a number of drawbacks, for example:

• leaded wires require a long and delicate installation, especially in dark and difficult to access places. They require anchor points specially designed for their use, and their heterogeneous structure makes it easy to spot their weak points and relatively easy for an unauthorized person to dismantle and reassemble them with minimal traces. In addition, the materials used quickly tarnish on contact with the atmosphere or chemicals, quickly erasing any traces resulting from the disassembly and reassembly of the lead;
• waxes and varnishes are easy to obtain and it is therefore easy for anyone to reconstruct the original seal, except in the case of the use of a very special graphics, but this then reduces the use to surfaces flat;
• the systems with snap-in half-shells offer, by their structure (presence of hinges and a snap-in system, significant clearance with respect to the substrate), several possibilities of access to the unauthorized user, that it is easy to spot. As a result, these systems are easy to defraud without leaving traces or by leaving only traces that are difficult to detect under the conditions due to the environment in which the equipment is used.

Also known, from document WO-A-83/02436, a seal consisting of an envelope arranged to cover at least part of the object or objects to be covered, and having areas of weakness such as an attempt to manipulate this seal produces its rupture.

The document FR-A-1,213,931 also discloses such an envelope further presenting well-localized initiations of rupture.

Furthermore, document US-A-3 935 960 discloses a sealing film for a container, the handling of which is demonstrated by its color change. For this purpose, the film includes cells filled with a liquid chemically reacting with the film when, after handling, the cells have been ruptured.

The known envelopes having areas of weakness give satisfaction. However, since they must be threaded onto the object, either they have a play with respect to it allowing threading, in which case, they may not apply intimately to the object, or they do not have not this play, in which case the envelope is force-fitted onto the object and a premature rupture of the seal may occur.

In document US-A-4,485,269, it is also known to cover a connector by means of a heat-shrinkable envelope ensuring the sealing thereof.

The problem which the invention aims to solve is therefore to propose a seal which can be easily brought to the object and which, moreover, applies intimately to it.

To this end, the invention relates to a seal intended to detect access to an object or a relative movement between several juxtaposed objects, consisting of an envelope arranged to cover at least a part of said object (s) and having zones of weakness such that an attempt to manipulate this seal produces its rupture, characterized in that the envelope is of such a material and has dimensions such that it is capable of being expanded, from '' a dimensionally stable configuration, towards a dimensionally unstable configuration in which it has determined dimensions, greater than those of said parts of the object to be covered, so that it can be brought around said parts while leaving a clearance between it and these parts, then retract towards said stable configuration in which it is applied by force to said parts, the fragility of said zones of weakness being increased by the retraction.

Thus, in its dimensionally unstable configuration, the envelope has dimensions which are greater than those of the object, which facilitates its positioning. Once returned to its dimensionally stable configuration, it applies intimately to the object. This return to the stable configuration is moreover used to increase the fragility of the zones of weakness, since it causes stresses in the envelope.

In the following description, this process of moving from a dimensionally unstable configuration to a dimensionally stable configuration will be called "dimensional recovery". In the case where this passage is caused by heating, we speak of a "thermal recovery".

Advantageously, the envelope is made of a heat-shrinkable material, and it optionally includes a product capable of reacting exothermically.

As a variant, the envelope is made of an elastic material and the seal includes means arranged to maintain the envelope in its dimensionally unstable configuration, these means being able to be removed to allow it to retract towards its stable configuration.

According to a preferred embodiment, the zones of weakness result from the presence of recesses in the envelope, which delimit envelope regions of small width. Thus fraudulent manipulation of the seal will very quickly cause the envelope to rupture in at least one of said regions of small width.

Advantageously, the envelope comprises a central region disposed between two terminal regions, said recesses being located in the central region and delimiting several strips each connecting the two terminal regions.

Advantageously, the seal includes regions of initiation of rupture, the presence of which increases the embrittlement of the envelope.

Advantageously, each strip is connected to the terminal regions by a portion of reduced section.

Another problem which the invention aims to solve is to be able to detect the unauthorized removal of a seal.

For this purpose, the seal comprises means arranged to leave a mark on the object after its removal.

Advantageously, said means comprise a product contained in the seal and capable of marking the object.

As a variant, said means comprise an adhesive interposed between the seal and the object.

Another problem which the invention aims to solve is, in the case of the recovery of objects capable of being moved in one of two opposite directions, to detect fraudulent manipulation both in one direction and in the other.

To this end, each strip is connected to one of the end regions by a portion of reduced section arranged near a first edge of the strip, and it is connected to the other end region by a portion of reduced section arranged near a second edge of the strip opposite the first.

The invention also relates to a method for applying the aforementioned seal, consisting in bringing the previously expanded seal to its dimensionally unstable configuration, around said parts of the object to be covered, causing the seal to retract to its stable configuration, and subjecting said audit sealed, after retraction, a treatment designed to increase the fragility of said zones of weakness.

This process contributes even more to obtain a seal which is especially fragile once assembled, and which therefore has an even greater resistance before assembly, for its manufacture and its installation.

• la figure 1 est une vue en perspective d'un scellé selon l'invention ;
• la figure 2 est une vue de détail agrandie d'une des bandes du scellé de la figure 1 ;
• la figure 3 est une vue en élévation du scellé monté sur un raccord de conduites de fluide ;
• la figure 4 est une vue en élévation du raccord, le scellé étant représenté en coupe longitudinale avant qu'il soit appliqué par reprise dimensionnelle sur le raccord,
• La figure 5 est une vue de face d'un scellé selon une seconde forme de réalisation de l'invention,
• la figure 6 est une vue de côté du scellé de la figure 5,
• la figure 7 illustre une utilisation du scellé des figures 5 et 6, et
• la figure 8 est une vue de détail agrandie, d'une variante de la figure 7.

Other details and advantages of the invention Will appear during the following description of a preferred but not limiting embodiment, with reference to the appended drawings in which:

• Figure 1 is a perspective view of a seal according to the invention;
• Figure 2 is an enlarged detail view of one of the strips of the seal of Figure 1;
• Figure 3 is an elevational view of the seal mounted on a fluid pipe fitting;
• FIG. 4 is an elevation view of the connector, the seal being shown in longitudinal section before it is applied by dimensional recovery to the connector,
• FIG. 5 is a front view of a seal according to a second embodiment of the invention,
• FIG. 6 is a side view of the seal of FIG. 5,
• FIG. 7 illustrates a use of the seal of FIGS. 5 and 6, and
• FIG. 8 is an enlarged detail view of a variant of FIG. 7.

The seal shown in Figures 1 to 4 is a dimensional recovery sleeve which comprises two rings 2,3 having the same axis 5 and spaced from each other, which are connected together by a plurality of bands or straps 4 extending parallel to axis 5 and distributed around it. In this example, there are six suspenders.

Each strap 4 extends in width over a portion of the periphery of the sleeve and has two ends by which it is connected respectively to two edges 6,7 of the rings, turned towards one another.

At the two ends of each strap 4, a slot 10,11 partially separates the strap from the edge 6,7 of the adjacent ring. The slot 10 extends from a first edge 12 of the strap towards the inside of the latter, over a distance corresponding to a half-width of the strap.

The other slot 11 extends from a second edge 13 of the strap towards the inside thereof, over the same distance as the slot 10.

• . circonférence du manchon   : 120 mm
• . largeur des anneaux   : 10 mm
• . longueur des bretelles   : 20 mm
• . largeur des bretelles   : 2 mm
• . épaisseur du manchon   : 0,5 mm

As an indication, the dimensions of a sleeve are specified below, before dimensional recovery or constriction, intended to cover a water pipe connection nut having a nominal diameter of 25.4 mm:

• . sleeve circumference: 120 mm
• . width of the rings: 10 mm
• . strap length: 20 mm
• . strap width: 2 mm
• . sleeve thickness: 0.5 mm

• a) - Ceux comportant un élément creux à reprise dimensionnelle radiale possédant au moins une extrémité ouverte et maintenu dans un état radialement dilaté par des moyens de contrainte disposés extérieurement à l'élément au moyen d'une liaison entre la surface extérieure de cet élément et la surface intérieure des moyens de contrainte, liaison qui peut être rompue pour permettre à l'élément de se rétracter radialement. Un tel objet peut être obtenu par injection de polychlorure de vinyle sur un tube en élastomère dilaté (néoprène) constituant l'élément de reprise. La reprise dimensionnelle est alors obtenue en brisant par choc la coque en polychlorure de vinyle et en enlevant les débris (on peut s'aider si nécessaire d'un solvant) . Selon d'autres formes de réalisation connues, l'élément creux comporte des moyens de contrainte disposés intérieurement.
• b)- Ceux à reprise dimensionnelle d'origine thermique, c'est à dire ceux qui ont été déformés d'une première configuration thermiquement stable à une deuxième configuration thermiquement instable et qui sont capables de reprendre la première configuration ou de tendre à nouveau vers celle-ci lorsqu'on leur applique de la chaleur uniquement. Dans le cas de l'invention ils peuvent se présenter sous différentes formes :
  • I) Sous forme de morceaux de gaine extrudés ou moulés à partir de polymères comme par exemple les polyoléfines (modifiées ou non), le fluorure de polyvinylidène ou le polychlorure de vinyle, et ayant au moins une extrémité ouverte. On pourra faire en sorte que l'interface entre le morceau de gaine et le susbstrat soit occupé par un adhésif thermo-fusible ou un auto-adhésif ou tout autre adhésif, soit que celui-ci soit d'une nature différente de celle du polymère de la gaine (polypropylène, polyéthylène, polyamides, résines époxy ou polyuréthanne...), soit qu'il soit issu de la gaine elle même par une différence de traitement entre l'extérieur et l'intérieur de celle-ci. (moindre réticulation...).
  • II) Sous forme d'une feuille capable de reprise thermique enveloppant l'objet à recouvrir et dont les extrémités sont maintenues bout à bout et en place soit par un moyen mécanique restant à demeure, soit par soudure (utilisation d'un matériau auto-soudable par chauffage tel le copolymère d'éthylène et d'acétate de vinyle).
  • III) Sous forme d'une bande capable de reprise thermique longitudinalement sans variation sensible de sa largeur qu'on enroule autour de l'objet avec du recouvrement et dont la face intérieure a des propriétés adhésives.

Several types of dimensional recovery objects usable for the invention exist:

• a) - Those comprising a hollow element with radial dimensional recovery having at least one open end and maintained in a radially expanded state by stress means arranged outside the element by means of a connection between the external surface of this element and the inner surface of the constraint means, a connection which can be broken to allow the element to retract radially. Such an object can be obtained by injection of polyvinyl chloride on an expanded elastomer tube (neoprene) constituting the recovery element. The dimensional recovery is then obtained by crashing the polyvinyl chloride shell and removing the debris (we can help if necessary with a solvent). According to other known embodiments, the hollow element comprises constraint means arranged internally.
• b) - Those with dimensional recovery from thermal origin, ie those which have been deformed from a first thermally stable configuration to a second thermally unstable configuration and which are capable of resuming the first configuration or of tending again towards this when only heat is applied to them. In the case of the invention, they can take various forms:
  • I) In the form of pieces of sheath extruded or molded to starting from polymers such as, for example, polyolefins (modified or not), polyvinylidene fluoride or polyvinyl chloride, and having at least one open end. We can make sure that the interface between the piece of sheath and the substrate is occupied by a hot-melt adhesive or a self-adhesive or any other adhesive, or that it is of a different nature from that of the polymer. sheath (polypropylene, polyethylene, polyamides, epoxy resins or polyurethane ...), either that it comes from the sheath itself by a difference in treatment between the exterior and the interior thereof. (less crosslinking ...).
  • II) In the form of a sheet capable of thermal recovery enveloping the object to be covered and the ends of which are held end to end and in place either by mechanical means remaining permanently, or by welding (use of a self- heat sealable such as ethylene vinyl acetate).
  • III) In the form of a strip capable of thermal recovery longitudinally without appreciable variation in its width which is wrapped around the object with covering and the inner face of which has adhesive properties.

In all cases, the thickness of the article with dimensional recovery is small so that it is fragile and significant lesions appear at the slightest attempt to set in motion one of the pieces of the fitting relative to the other, or access to the protected object. The presence of an adhesive is not obligatory but further amplifies the extent of the destruction of the object with thermal recovery.

During small movements of the pieces of the fitting with respect to each other, it is even possible to add small hard particles (quartz, alumina, etc.) in the adhesive to improve the bonding on the pieces of the fitting.

The materials used for the heat recovery objects will preferably be polymers (polyolefins - modified or not -, PA, PVC) and may be crosslinked.

Thermal recovery can be obtained by heating by hot air, flame or immersion in a liquid at the appropriate temperature. The heat source can also be incorporated into the polymer used for the manufacture of the object with thermal recovery, for example in the form of a product distributed on the external face of the object and reacting exothermically with water.

In the case of heat-shrinkable objects manufactured by extrusion, it is possible to coextrude several strips of different color and therefore to make these objects specific to anti-fraud use and not reproducible by unauthorized third parties. It is also possible to make prints on these objects.

FIG. 3 illustrates a use of the seal according to the invention with a view to detecting an unauthorized disassembly of a connection between two fluid lines 21, 22, one of them being for example directly connected to a reservoir, the connection between the two conduits being produced by means of a nut 23.

Before closing the connector, the sleeve 1 of FIG. 1 is slid over one of the pipes 21, 22. After closure of the connector, the sleeve 1 is disposed opposite it, so that its straps 4 are opposite the nut 23, preferably facing the sides 25, 26 of the nut.

When the sleeve 1 is applied to the connector, the rings 2,3 are preferably retracted first on the pipes 21,22, then that of the straps 4 on the nut 23.

After retraction of the sleeve, the regions of the straps comprising the slots 10, 11 are the seat of particularly high stresses, such as an attempt at unauthorized manipulation of the sleeve or the nut will lead to rapid rupture of the straps 4. Thus, very advantageously, the sleeve has a brittleness especially after its retraction, while before it its resistance is sufficient not to tear during the manufacturing process and during assembly.

Advantageously, the particular arrangement of the slots 10, 11 on the sleeve promotes the rupture of the straps regardless of the direction in which the nut 23 is rotated and regardless of the direction of mounting of the sleeve thus, when the latter is rotated in the direction of the arrow 24 (FIG. 2), it is the end of the straps 4 carrying the slot 11 which will have the best chance of detaching from the sleeve, because the direction of the force tends to open the breach produced more by the presence of the slot.

Another advantage of the sleeve according to the invention appears in FIG. 4, in the case where the space available on either side of the connector is limited to a length less than that of the sleeve. Due to the presence of the straps 4, the rings 2,3 can be brought closer to each other, which causes the straps to fold back on themselves and therefore a reduction in the length of the sleeve.

As an alternative to the embodiment described above, all kinds of recess shapes may lead to the areas of weakness of the seal being obtained. In particular, these recesses may consist of a large number of juxtaposed holes of small dimensions.

However, and preferably, the recesses will be such that, when viewed in projection in a plane perpendicular to the axis of the sleeve, they produce a reduction in section of the sleeve at least equal to 1% relative to a section of the sleeve which would be devoid of recesses. Preferably the reduction in section will be greater than 50%; it reaches 95% in the above example, measured in the region of the straps 4.

It will be noted that the presence of suspenders is particularly advantageous since these give the seal a fragile appearance which dissuades the unauthorized third party from handling the covered object.

As an alternative to the embodiment described above, the seal according to the invention may have weaknesses resulting, not from the presence of recesses on its surface, but from the very nature of the material constituting the seal or its weakness. thickness.

The fragility of the zones of weakness may be increased, after shrinking, by a special treatment (heating, projection of an agent attacking the material, etc.), for example by making the material brittle or weakly resistant to traction.

In the case where the seal is intended to be threaded on one end of the object (s), it may take the form of a cap.

The seal shown in a variant in FIGS. 5 to 7 is a ring-shaped belt 30 having zones of weakness distributed around the periphery and formed on the one hand by zones of reduced thickness 31, and on the other hand by slots 32. In the zones of reduced thickness 31, which extend peripherally over a very short length, the thickness of the belt 30 is reduced by 60% in this example.

Furthermore, the slots 32 extend in this example over 40% of the width of the belt, from any edge thereof towards the inside. The slots 32 are grouped peripherally in pairs, in the sense that each slot extending from one edge of the belt 30 faces another slot extending from the other edge of the belt.

In Figure 7, the belt 30 has been arranged by dimensional recovery on a box 33 having a cover 34. The box 33 may in particular contain connections between two pipes or cables, or serve to store and transport dangerous or precious substances.

The belt 30 is arranged so as to overlap the cover 34. Due to the dimensional recovery, the zones of reduced thickness 31 have been stretched peripherally and the slots 32 have been opened.

To oppose an attempt to remove the belt by sliding along the box 33, two solutions are proposed. The first is to interpose an adhesive between the belt and the box. The second consists in using a box 35 having a groove 36 completely surrounding it, arranged to receive the belt 30.

Given the intimate contact that it is possible to obtain between the seal according to the invention and the substrate on which it is placed, an improvement of the invention consists in that the seal leaves traces of its installation on the substrate. , even after its total withdrawal.

The effect is obtained by the presence of a substance, at least on the inner face of the seal in contact with the substrate, such that, once the seal has been removed, the parts of the surface of the substrate having been in contact with the seal look different from other parts of the substrate surface.

• substrats en polymères : on utilise un colorant capable de migrer au sein même du polymère constituant le substrat, ce phénomène étant avantagé par la pression due à la reprise dimensionnelle ainsi que par la température nécessaire à celle-ci (par exemple colorant à base de rouge de cadmium, jaune de cadmium etc...)
• substrats métalliques : on utilise une substance capable de créer une légère corrosion superficielle du substrat, par exemple une substance présentant une légère acidité, une substance comprenant des composés de l'ammoniaque capable de provoquer un léger appauvrissement en zinc dans des alliages à base de cuivre et zinc, tels que le laiton.
• pour tous les types de substrats, on peut utiliser un adhésif dont une partie reste sur le substrat après retrait du scellé, soit parce qu'il adhère davantage sur le substrat que sur le scellé, soit parce que l'adhérence entre le substrat et l'adhésif est supérieure à la résistance intrinsèque de l'adhésif.

Depending on the substrates, the substances used (which can be an integral part of the material constituting the seal) can be very different:

• polymer substrates: a dye capable of migrating within the polymer constituting the substrate is used, this phenomenon being favored by the pressure due to the dimensional recovery as well as by the temperature necessary for this (for example dye based on red cadmium, cadmium yellow etc ...)
• metallic substrates: a substance capable of creating slight surface corrosion of the substrate is used, for example a substance having a slight acidity, a substance comprising ammonia compounds capable of causing a slight depletion of zinc in copper-based alloys and zinc, such as brass.
• for all types of substrates, an adhesive can be used, part of which remains on the substrate after removal of the seal, either because it adheres more to the substrate than to the seal, or because the adhesion between the substrate and the The adhesive is greater than the intrinsic strength of the adhesive.

The invention finds its application in particular in the covering of fluid conduit fittings, or of electrical or optical cable fittings, of threaded ends of compressed gas bottles (medical gas for example) and in the covering of boxes.

Claims (13)

1. Seal designed to detect access to an object or relative movement between several objects (21,22) adjacent one another, constituted by an envelope (1) arranged to cover at least a part of the object(s) and having zones of weakness such that any attempt at manipulation of this seal generates the rupture of these, characterised in that the envelope is of such material and has such dimensions that it can be expanded, starting from a dimensionally stable configuration, towards a dimensionally unstable configuration in which it has certain dimensions greater than those of the said parts of the object to be covered in such a fashion that it can be led around the said parts while providing play between itself and these parts and then it can retract itself towards the said stable configuration in which it applies a force to the said parts, the fragility of the said zones of weakness being increased by the retraction.
2. Seal according to Claim 1, in which the envelope (1) is of a heat shrinkable material.
3. Seal according to Claim 2, in which the envelope (1) includes a product which can react exothermically.
4. Seal according to Claim 1, in which the envelope (1) is in an elastic material and the seal comprises means adapted to maintain the envelope (1) in its dimensionally unstable configuration, these means being able to be shrunk in order to permit this to shrink towards its stable configuration.
5. Seal according to any one of the preceding Claims, in which the said envelope (1) comprises openings defining regions of the envelope of narrow width (4).
6. Seal according to Claim 5, in which the envelope comprises a central region located between two end regions (2,3), the said apertures being located in the central region and defining several strips for connecting the two end regions (2,3) in each case.
7. Seal according to any one of the preceding Claims which includes rupture starter regions (10,11; 31,32).
8. Seal according to Claim 6 and Claim 7 taken together, in which each strip (4) is connected to the end regions (2,3) via a portion of reduced section.
9. Seal according to Claim 8, in which each strip (4) is connected to one (2) of the said end regions by a portion of reduced section located next to a first edge (12) of the strip and it is connected to the other end region (3) by a portion of reduced section disposed next to a second edge (13) of the strip opposed to the first.
10. Seal according to any one of the preceding Claims which comprises means adapted to leave a trace on the object following its shrinkage.
11. Seal according to Claim 10, in which the said means comprise a product contained in the seal and capable of marking the object.
12. Seal according to Claim 10, in which the said means comprise an adhesive located between the seal and the object.
13. Process of applying a seal according to any one of the preceding Claims on to the object or objects to be covered, characterised in that it consists in:

    - feeding the seal which has been previously expanded towards its unstable dimensional configuration around the said parts of the object to be covered;

    - promoting the shrinkage of the seal towards its stable configuration; and

    - subjecting the said seal, following shrinkage, to a treatment intended to increase the fragility of the said zones of weakness (4,10,11).

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