ANTI-THEFT SYSTEM

Abstract: An anti-theft system comprises, on the one hand, a locking part (2) provided with a housing which has a locking mechanism (3-6), and also a counterpart (1) which can be connected to the locking part (2) and, on the other hand, a magnetic release element (21) which can be placed on the housing for the release of the locking part relative to the counterpart. In order to give greater security, the housing of the locking part (2) has a key (18, 19), and the release element (21) has a counter key (24, 25), which key (18, 19) and counter key (24, 25) fit into each other.

Description: Anti-theft system The invention relates to an anti-theft system comprising, on the one hand, a locking part provided with a housing which has a locking mechanism, and also a counterpart which can be connected to the locking part and, on the other hand, a magnetic release element which can be placed on the housing for the release of the counterpart relative to the locking part. Such a system is known from Dutch Patent Application NL-A- 88OO367. The release element thereof has a powerful permanent magnet, by means of which the locking mechanism can be released. This release is achieved as soon as the magnet is brought close enough to the locking mechanism, in such a way that a part made of magnetisable metal present therein can be attracted. In order to obtain the minimum distance necessary, the housing of the locking part and the release mechanism must be corresponding shapes which make it possible for locking part and release element to be brought closely against each other. In practice, this requirement amounts to the housing being a convex shape, and the release element being a corresponding concave shape. The advantage of these shapes is also that a specially shaped release element is necessary, with the result that release by unauthorized persons is made difficult. However, it is increasingly being found that release elements shaped in this way fall into the hands of third parties, which lessens the security function of the existing anti-theft systems. The availability of increasingly powerful permanent magnets also means that the locking mechanism can be released even without the special shape of release element. With these more powerful magnets the distance from the magnetisable part need not be so small, with the result that the locking is released even where the magnet cannot be brought as close up as was necessary in the case of the magnets originally used. There is therefore a need for an anti-theft system which also provides protection against the use of the release elements and/or powerful magnets now circulating among some members of the public. This object is achieved through the fact that the housing of the locking part has a key and that the release element has a counter key, which key and counter key fit into each other. In the case of the system according to the invention the release element can be brought close enough to the housing only if the key and the counter key match each other exactly. Where a key does not match, the distance remains too great, with the result that release is not possible. Contrary to what has been the case hitherto, it is possible for one or more sales outlets to use a unique key on the release elements and to use a corresponding, likewise unique counter key on the locking parts. Sales outlets in a specific area can now each have their own combination which differs from the other key/counter key combinations, with the result that it becomes virtually impossible for unauthorized persons to find out the sales outlet at which a release element can be used, even if they are able to obtain such a release element. The key/counter key combination can be in many different forms. However, according to a preferred embodiment, the key comprises at least one projection, and the counter key a corresponding number of correspondingly shaped recesses. The projections on the key present on the housing make it impossible to use the release elements currently in circulation, these elements having a smooth accommodation recess for the housing. In order to increase the number of possible different key combinations, the key can comprise at least two projections which lie at different levels in the insertion direction of key and counter key and are displaced relative to each other in the peripheral direction. According to a first practical embodiment, the system can comprise a detection element which can be set up in a fixed position and also a tag with a detection coil which is detectable by the detection element, which tag interacts with the counterpart or the locking part. In this case the tag can be made integral with the counterpart, or it can be detachably connected to the counterpart, in such a way that the tag can be removed from the counterpart after releasing therefrom. Good security is obtained if the counterpart is provided with a fluid reservoir for an essentially indelible fluid, which reservoir is designed in such a way that the fluid can escape from it when the locking mechanism is forced. Such a counterpart is already known per se. The protection can be improved even further if the housing of the locking part also has a fluid reservoir for an essentially indelible fluid, which reservoir is designed in such a way that the fluid can escape from it when the locking mechanism is forced. The invention also relates to a locking part for use in the system described above. The preferred locking part is one in which the housing comprises a base part and a cap part, and both the base part and the cap part bear a projection. Of course, more than two projections can also be provided on the housing. A large number of different key combinations can be achieved in the case of an embodiment of the counterpart in which the connection surfaces of base part and cap part are rotationally symmetrical, in such a way that both projections can be fixed to each other in any desired displaced position. Forcing of the system is made even more difficult if, as described, not only the counterpart but also the locking part has a reservoir with an essentially indelible fluid. In that connection, destruction of the projections forming the key can be made unattractive if at least one of the projections is hollow, and the interior space thereof is in communication with the reservoir. The invention also relates to a release element for the system described above. Said element is preferably provided with a hollow which is formed corresponding to the housing, at least a part thereof being clad with ceramic material. Since ceramic material is very hard and difficult to work, the release element is virtually impossible to uncover, so that the magnet remains inaccessible. This embodiment is a good idea in particular if a relatively powerful magnet which is difficult to obtain is being used. In this respect a further improvement can be obtained if the recesses are provided in the ceramic cladding and/or the magnet. The hardness of the ceramic material prevents the recesses from being adapted. The invention will be described in greater detail below with reference to an example of an embodiment shown in the figures. Figure 1 shows a view, partially in section, of a locking part with counterpart according to the invention; Figure 2 shows a top view of the locking part; Figure 3 shows a first variant of locking part and counterpart; Figure shows a second variant of locking part and counterpart; Figure 5 shows a release element according to the invention, with locking part and counterpart according to Figure 1; Figure 6 shows an alternative locking part. The anti-theft system shown in Figures 1 and 2 comprises a partially shown counterpart 1, in addition to a locking part 2 according to the invention. The counterpart 1 can be in various forms. In the embodiment shown, it is in the form of a flat plate, on which plate the electronic components of a security system are fitted. Such security systems are known, so that no further description thereof is given. Apart from the plate 28, the counterpart 1 has a pin 3ι which has a sharp point, so that it can be inserted through a piece of material, for example a garment. At the side of the locking part 2 facing the plate 28 is an opening into which the pin 3 is inserted. After insertion of the pin 3 into said opening, the pin is held in place by means of a further known locking mechanism which, as shown, can have, for example, three balls 4. Balls 4 are pressed by pressure part 5 towards the narrowed part of a conical seat 6, under the influence of a spring 7• Such a locking mechanism is also known, so that no further detailed description thereof is given. The locking mechanism, indicated in its entirety by 8, is accommodated in a bowl 9. forming part of the base part 10 of locking part 2. Said locking part 2 also has a cap part 11 which is connected in a sealing manner to the base part 10. Base part 10 has a specially shaped sealing edge 12, while cap part 11 also has a specially shaped sealing edge 13- When the locking part 2 is being assembled, base part 10 and cap part 11 are placed on one another, the sealing edges 12 and 13 already providing a seal before the parts 10 and 11 are pressed fully onto each other. When said parts 10 and 11 are pressed further towards each other, this results in an excess pressure in the interior space bounded by the parts 10 and 11. The parts are then fixed to each other, for example by ultrasonic welding. Excess pressure consequently prevails in the reservoir I enclosed by the parts 10 and 11, which means that the indelible fluid 15 therein, for example ink, is also under pressure. As soon as an attempt is now made to force the locking part, for example to open the locking mechanism 8, the reservoir 14 will very quickly be opened, with the result that the fluid gushes out under the influence of the excess pressure. This ensures that when the locking part 2 is forced the garment protected by it becomes unusable. In order to facilitate the correct assembly of base part 10 and cap part 11, the base part 10 has a number of radially inward directed plates 16 disposed at regular intervals on its inner periphery. The cap part 11 has an apron 17, the free end of which is centred by the plates 16. According to the invention, the base part 10 now has a projection 18, and the cap part 11 has a projection 19- In Figures 1 and 2 these are fitted at the same place in the peripheral direction of the locking part 2, so it is clear that during manufacture of the locking part 2 these keys 18 and 19 can be at any position relative to each other in the peripheral direction. This means that a large number of different combinations of projections 18 and 19. together forming the key of the locking part, are obtained. As can be seen in Figure 1, the key 19 contains a hollow space 20, which forms part of the fluid reservoir. As soon as any attempt is made to remove the projection, the fluid under pressure will gush out. If projection 18 is being forced, the reservoir lk can also be broken, with the same effect. In the case of the variant shown in Figure 3. the locking part 2 is itself provided with an integral tag 29- This tag 29, which is only partially shown, again bears a coil, which can be detected as described above. In the case of this variant the counterpart can be in the form of a so-called spike 30. The variant of the system shown in Figure k again comprises a locking part 2 of the same type as that shown in Figures 1 and 2. However, the counterpart 3 is in this case also provided with a fluid reservoir 32. Such a counterpart 31 is known per se from Dutch Patent Application NL-A-9001337- In the case of this variant also, the locking part 2 can, of course, be provided with an integral tag with detection coil, as shown in Figure 3- This embodiment of the security system is very difficult to force, since both the counterpart 31 and the locking part 2 now have a breakable fluid reservoir. Figure shows in greater detail how the locking part 2 can interact with the release mechanism indicated in its entirety by 21. This release element has an accommodation recess 22, the shape of which corresponds to that of the housing 23 (formed by cap part 11 and base part 10) of the locking part 2. In particular, the projections 18 and 19 can be accommodated in correspondingly shaped recesses 2k and 25, in the accommodation recess 22 of release element 21. It can also be seen that a tag 33. provided with a hole 3^ into which the pin 3 of counterpart 30 is inserted, can be used. This tag has a detection coil which is detectable in the manner described above. Figure 6 shows an alternative locking part 36, in the case of which keys 37 are also fitted on the flat side of the housing. An even larger number of different key combinations can be obtained with this alternative. Of course, the magnet of the release element (not shown) is in this case also provided with corresponding recesses. The keys 37 are provided with a hollow 38 in communication with the reservoir. If an attempt is made to remove the keys, the reservoir is broken. Release element 21 also has a powerful permanent magnet 27, which is accommodated in a sleeve 26 of ceramic material. This sleeve of ceramic material 26 is very hard, so that the magnet is well protected. The recesses 2k and 25 are also partially provided in this ceramic material, which means that it is virtually impossible to change their shape. This means additional security in the case of the system according to the invention, since it is virtually impossible to make recesses in the ceramic material of the sleeve 26 itself, with a view to releasing counterparts 23 with different keys. Only one specific release element 21 with the counter key determined by the recesses 2k and 2 thus matches each counterpart 2 with a key determined by the projections 18 and 19.

Claims: Claims 1. Anti-theft system comprising, on the one hand, a locking part provided with a housing which has a locking mechanism, and also a counterpart which can be connected to the locking part and, on the other hand, a magnetic release element which can be placed on the housing for the release of the locking part relative to the counterpart, characterized in that the housing of the locking part has a key and in that the release element has a counter key, which key and counter key fit into each other. 2. System according to Claim 1, in which the key comprises at least one projection, and the counter key comprises a corresponding number of correspondingly shaped recesses. 3- System according to Claim 2, in which the key comprises at least two projections which lie at different levels in the insertion direction of key and counter key and are displaced relative to each other in the peripheral direction. k . System according to one of the preceding claims, in which an electronic detection device is provided, comprising an electronic detection element which can be set up in a fixed position and also at least one tag with a detection coil which is detectable by the detection element, which tag interacts with the counterpart or the locking part. 5- System according to Claim 4, in which the tag is integral with the counterpart. 6. System according to Claim k , in which the tag is detachably connected to the counterpart, in such a way that the tag can be removed from the counterpart after releasing therefrom. 7- System according to one of the preceding claims, in which the counterpart is provided with a fluid reservoir for an essentially indelible fluid, which reservoir is designed in such a way that the fluid can escape from it when the locking mechanism is forced. 8. System according to one of the preceding claims, in which the housing of the locking part has a fluid reservoir for an essentially indelible fluid, which reservoir is designed in such a way that the fluid can escape from it when the locking mechanism is forced. 9- Locking part for an anti-theft tag according to one of the preceding claims. 10. Locking part according to Claim 9 for a system according to Claim 3. in which the housing comprises a base part and a cap part, and both the base part and the cap part bear a projection. 11. Locking part according to Claim 10, in which the connecting surfaces of base part and cap part are rotationally symmetrical, in such a way that both projections can be fixed to each other in any desired displaced position. 12. Locking part according to Claim 10 or 11, in which at least one of the projections is hollow, and the interior space thereof is in communication with the reservoir. 13. Locking part according to one of Claims 9 - 12, in which one or more projections are provided on the end face of the housing. Ik . Release element for a system according to one of the preceding claims. 15. Release element according to Claim Ik , provided with a hollow which is formed corresponding to the housing, in which at least a part of said hollow is clad with ceramic material. 16. Release element according to Claim 15, in which the recesses are provided in the ceramic cladding. 17. Release element according to Claim 15 or 16, in which provision is made for a magnet which has a recessed part which forms part of the hollow. 18. Release element according to Claim 17, in which at least one of the recesses continues into the magnet.

Inventors: SCHRAUWEN GERARDUS PETRUS ANTO, SCHRAUWEN, GERARDUS, PETRUS, ANTONIUS, MARIA
Applicants: HENDRIKX JACOBUS GERARDUS MARI, SCHRAUWEN GERARDUS PETRUS ANTO, HENDRIKX, JACOBUS, GERARDUS, MARIA
Application year: 1993
Main classification: E05B73
IPC codes: E05B39, E05B47, E05B73