ALARM SYSTEM FOR SAFEGUARDING AGAINST THE BREAKTHROUGH OF A SURFACE

Abstract: An alarm system in the form of a support layer is arranged to be secured to a wall, and is provided with a printed circuit of a series (1) of electrical conducting wires in a particular pattern (fig. 1) on both the front and the back. The wires lie very close side by side and crosswise to each other, thus forming a mesh pattern. Some of the wires are current-carrying while others are not. If just one of the wires is cut over or carries a voltage other than that applied to it, the alarm is activated. The alarm system is simple and easy to produce because printed circuits are used, and the support layer is impossible to break through.

Description: ALARM SYSTEM FOR SAFEGUARDING AGAINST THE BREAK¬ THROUGH OF A SURFACE. This invention relates to an alarm system for the safeguarding against the breakthrough of a surface, for example a wall, the wall of a suitcase or a pane of glass, said system being of the kind where a pat¬ tern or network of electrical conducting wires or leads are distributed uniformly over the surface. With such known systems,-where the leads lie in one layer, it is possible in principle for a criminal to remove a section of a lead after having short-cir¬ cuited its ends with the help of a longer length of lead. In this manner it is possible with repeated operations in a chosen area to create an opening which is sufficiently large to enable stolen goods to be passed through. The object of the present invention is to provide a construction without this drawback and, moreover, having several advantages. The alarm system according to the invention is char- acteristic in that the wires are arranged to lie in at least two surfaces, preferably plane surfaces ly¬ ing at a small distance from each other seen at right angles to the surfaces, that the wires are comprised of a series consisting of the number n of wires, that this series runs uninterrupted through the surfaces so that the assembled network has the number n of input terminals and the number n of out¬ put terminals, that these terminals are connected to a current supply, a microprocessor or other elect- ronics and an alarm in such a way that to a number OMPI of the wires n there are applied other voltages or signals in relation to the remainder, and that the microprocessor or the electronics unit is arranged to activate the alarm in the event of the voltage or the signals on just one of the output terminals not corresponding to the voltage or the signals on the corresponding input terminal. By dimensioning such a system in a suitable manner, i.e. with conveniently close-lying wires seen both in the directionsof the above-mentioned planes and at right angles thereto, it can be made very diffi¬ cult to remove a section of a given wire without at the same time damaging the wires in another layer and thereby activating the alarm. It will be obvious that the breadth and the pattern or patterns of the wires can be varied quite considerably without de¬ viating from the scope of the invention. According to the invention the individual surfaces can be connected in series, i.e., the series of wires runs first over the whole of the first sur¬ face, and from there further over the whole of the second and so on, hereby providing a very simple construction. Moreover, according to the invention the series in the first surface can be laid out in a pattern in such a manner that the wires are parallel with each other over the greater part of the surface area, and that the same is the case for the following surface or surfaces, but that the wires from surface to sur¬ face form angles to each other, hereby further ren¬ dering a breakthrough difficult. _O PI One embodiment of the system can be characterized by the wires being moulded into or enclosed in one or more insulating materials, for example by being laid out and secured on both sides of an insulating sup¬ port layer and thereafter covered with an insulating covering material. There is hereby provided a fin¬ ished product which can be despatched without being damaged, and which thereafter can be mounted at the place of application. A second embodiment can be characterized by an in¬ sulated support layer, composed of a so-called printboard, which is provided on both sides with a printed circuit and comprises two electrically con- nected wire surfaces, preferably connected in ser¬ ies. There is thus provided a construction which is not only simple to produce, but which also has the characteristics mentioned 'i ' connection with the foregoing embodiment. One can thus envision the in- sulating support layer as being wall decorating mat¬ erial, so that one can cover a whole wall with the support layer and then connect the individual sec¬ tions of the material in series, and thereafter con¬ nect it to the remaining part of the system. In this way and .with-simple -means it is thus possible to safeguard large wall areas and thereby safeguard complete rooms against break-in through the walls. Further developments of this embodiment can be char- acteristic in that the thickness of the printboard is less than 0.5 mm. What is obviously achieved here¬ by is a very flexible material, while the closer the individual wires in each surface lie to each other, the greater becomes the security against break- thro ch. OMPI The system according to the invention can be charact¬ erized by the series consisting of four wires. There is thus already provided many combinations for the application of voltages or signals or earth connec- tions to the individual wires. Finally, the system can be characteristic in that out of the number of wires n, the number m - where m<n - are applied with the same voltage, while tb -the remaining n-m is applied another potential, which is the same for all n-m, i.e., they are for example connected to frame. There is thus provided an ex¬ tremely simple construction whic " allows operation with constant voltages or no voltages throughout a section of the wires, and this provides a simple building up of the system. In the case of the pre¬ ferred embodiment, providing that there are four wires in a series, there is already the possibility of 16 combinations of voltages or non—voltages on the wires. The invention will now be described in closer de¬ tail with reference to the accompanying drawings, where fig. 1 shows in schematic form the run of a series of wires used in an alarm system according to the invention, but where for the sake of clarity the breadth of the series is greatly reduced. fig. 2 shows .in more detail the actual mutual distance between the wires, but where on the other hand the effective barrier area of the wire network is reduced out OMPI of regard for clarity, fig. 3 shows a coupling diagram for an alarm system according to the invention, and fig. 4 is a table showing the relationship be¬ tween input and output with regard to fig. 3. In fig. 1 the run of a series of wires is shown sche¬ matically by a broad black line. The one end of the series is shown at 1 and the other end at 2. The se¬ ries consists of 4 wires, i.e.,.n=4, but for the sake of clarity the four wires are shown as a broad black line, which in effect is not broad enough, in that the distance between the individual parts of the series in the places where it runs parallel to it¬ self is just as small as the distance between the individual wires. The first part of the series, which in the main consists of vertical lines, is mounted on the one side of a support layer, for ex¬ ample in the form of a printed circuit on a print- board, while the second part of the series, which in the main consists of horizontal lines (on the paper) , is mounted on the other side of the support layer. The transition from the one side to the other takes place at the loop 3, and this transition is to be considered schematic, in that in practice it would be executed in another manner. The support layer or the printboard can then be secured to or comprise a part of a wall in a suitcase or a strongbox, in that the whole of the wall surface is then covered. As mentioned, the parallel parts of the series 1 lie closer at the side of each other than shown in fig. 1. Fig. 2 shows a more realistic distance between the wires, where all the wires comprising the system lie at the same distance from each other in a square net. On the other hand, the effective barrier area in - . this schematic arrangement is very small in relation to the ineffective fringe area, which in practice does not occupy so much space. Fig. 3 shows a coupling diagram with a support layer or armoured print 4 symbolized.b a- dotted " .line, and which is imagined to contain that described in figs. 1 and 2. Four input termin¬ als can be connected to the terminals 6 in a power source 7. Every second of these terminals 6 are live, while the others are connected to earth. For a given production example one chooses to connect some of the terminals 5, i.e. the number m out of 4=n, to a live terminal, while the remainder are -connected -to earth. The output terminals 8 on the support layer or the armoured print 4 are connected to a micropro¬ cessor or an electronic unit 9 containing generally known electronics capable of distinguishing between . the possible combinations, and which is arranged to furnish an alarm symbolized by the arrow P in the event of the output not corresponding to the input at 5 and 6. Fig. 4 shows the possible combinations. Here it must be pointed out that in the case of a certain produc- tion example, no exchange is made between the men¬ tioned combinations. For a given production example one chooses to use one of the possible combinations. For example one can decide that the terminals A and B are to be curr nt-carrying, while.the remainder are to be connected to earth. This corresponds to line 4 in the table in fig. 4, where 1 signifies current -carrying and 0 signifies connection to earth. In the electronic unit 9 is placed a decoder which can accomodate 10 combinations - one will often prefer that this can accomodate all 16 combinations. The invention is naturally not limited to the use of four wires in a series (n=4) , but in practice it has proved that four wires and ten combinations are more than sufficient to provide the desired protection. With the example mentioned the protection is thus achieved by a voltage being applied to terminal 3 in the row 10, while the other terminals remain vol¬ tage-free in relation to earth. The system is arrang¬ ed to provide an alarm signal at the instant that this is not the case, and thus the alarm signal is produced when, 1) one of the current-carrying wires A or B is cut over. 2) one of the current-carrying wires is connec¬ ted to something which diverts the current, including for example one of the remaining leads , 3) a voltage is applied to one of the leads connected to earth. As the wires in the support layer as shown in fig. 1 and 2 can be arranged to lie very close to one an¬ other, and since a criminal attempting to break through cannot know which of the wires are current -carrying and which are not, it becomes impossible in practice to make holes in the support layer which are substantially larger than the size of the mesh. ,_OMPI & ■ >._ WiPO

Claims: C L A I M S 1. Alarm system for safeguarding against the break¬ ing through of a surface, for example a wall, the wall of a suitcase or a pane of glass, said system being of the kind in which a pattern or network of electrically conducting leads or wires are uniformly distributed over said surface, c h a r a c t e r ¬ i z e d in that the wires are arranged to lie in at least two surfaces, preferably plane surfaces lying at a small distance from each other seen at right angles to the surfaces, that the wires are comprised of a series consisting of the number n of wires, that this series runs uninterrupted through the sur¬ faces so that to the assembled network there belongs the number n of input terminals and the number n of output terminals, that these terminals are connected to a current supply, a microprocessor or other elec¬ tronics and an alarm in such a manner that a number of the wires n carry other voltages or signals in relation to the remainder, and in that the micropro- cessor or electronics are arranged to activate the alarm in the event of the voltage or the signals on just one of the output terminals not corresponding to the voltage or the signals on the corresponding input terminal. 2. System according to claim 1, c h a r a c t e r¬ i z e by the individual surfaces being connected in series, i.e., the series of wires runs first over the whole of the first surface, and from there fur- ther over the whole of the next and so on. 3. System according to claims l or 2, c h a r a c¬ t e r i z e d by the series in the first layer being OMPΓ laid out in a pattern in such a manner that the wires are parallel with each other over the greater part of the surface area, and that the same is the case for the following surface or surfaces, but that the wires from surface to surface form angles to each other. 4. System according to claims 1, 2 or 3, c h a r ¬ a c t e r i z e d by the wires being moulded into or enclosed by one or more insulating materials, for example by being laid out and secured to both sides of an insulating support layer, and thereafter being covered by an insulating covering material. 5. System according to claims 1, 2, 3 or 4, c h a r a c t e r i z e d by an insulating support layer consisting of a so-called printboard which is provided on both sides with a printed circuit, and which comprises two electrically connected wire sur¬ faces, preferably connected in series. 6. System according to claim 5, c h a r a c t e r¬ i z e d by the thickness of the printboard being less than 0.5 mm. 7. System according to one or more of the fore¬ going claims, c h a r a c t e r i z e d by the dis¬ tance between the individual wires in each surface being less than 5 mm. 8. System according to one or more of the fore¬ going claims, c h a r a c t e r i z e d by the series being comprised of four wires. 9. System according to one or more of the fore- going claims, c h a r a c t e r i z e d in that out of the number n of wires, the number m, where m<n, have the same voltage applied, while the remaining n-m have another voltage applied which is the same for all n-m, i.e., they are for example connected to earth. "BϋREAlT OMPI

Inventors: JOERGENSEN POUL RICHTER, JOERGENSEN, POUL, RICHTER
Applicants: JOERGENSEN POUL RICHTER, JOERGENSEN, POUL, RICHTER
Application year: 1982
Main classification: G08B13
IPC codes: G08B13, H05K1