| FR2080125A5 | 1971-11-12 | |||
| SE364791B | 1974-03-04 | |||
| DE2335772A1 | 1975-01-30 | |||
| DE2923732A1 | 1981-01-08 | |||
| EP0063876A1 | 1982-11-03 | |||
| US4092643A | 1978-05-30 | |||
| US4321592A | 1982-03-23 |
| 1. | An installation for surveillance of an area such as a ground area c h a r a c t e r i s e d by a cental unit such as an alarm and control centre (1) connected to one or more sensing means (3) located arbitrarily within the area, each sensing means preferably cooperating with one or more action member (5) , each sensing means (3) at a change of situation at the same as the appearance of an akustic change, of a change of light and of an object as a human being, an animal, a vehicle and the like causes an indication to the control unit (1) . |
| 2. | An installation according to claim 1, c h a r a c t e r i¬ s e d by .one or more members or obstructions (4) such as wires, cords, nets or the like included in a sensing means (3) which members or obstructions (4) at influence change the sensing means (3) so that said indication is obtained. |
| 3. | An installation according to claim 1, c h a r a c t e r i¬ s e d in that the central unit (1) includes switching means able to connect the central unit (1) to either a sensing means or to one or more action members (5) cooperating with the sensing means (3) . |
| 4. | An installation according to claim 3, c h a r a c t e r i ¬ s e d in that each sensing means (3) is connected electric¬ ally to the central unit (1) and contains one or more reed relays (6A,6B), each cooperating with a magnet (7A,7B) applie externally and individually connected to one or more of said obstructions (4A,4B). |
| 5. | An installation according to claim 4, c h a r a c t e r i ¬ s e d in that each sensing means (3) includes a resistor (8) which, for control purposes, is connected to the central unit (1) so long as all magnets (7A,7B) cooperate with their reed relays (6A,6B), each relay shortcircuiting said resistor (8) upon removal of the cooperating magnet (7A,7B). |
| 6. | An installation according to claim 4 or 5, c h a r a c t e ris e d in that each magnet (7A,7B) applied on a sensing means (3) is retained by a magnetic force which is preferably adjustable and of such magnitude that the trigger ing force on the cooperating obstruction is deemed extreme¬ ly slight. |
| 7. | An installation according to one or more of the preceding claims, c h a r a c t e r i s e d in that each sensing means (3) is provided with an external recess (13) for each magnet (7A,7B), said recesses being so shaped that the magnets re¬ main perfectly well in place when not subjected to external force, but that minimal force is required to cause a magnet to leave its recess. |
| 8. | An installation according to one or more of the preceding claims, c h a r a c t e r i s e d in that each sensing means (3) contains a rectifier which only permits current through , in one direction. |
| 9. | An installation according to one or more of the preceding claims, c h a r a c t e r i s e d in that each group of sensing means (3) is connected in series to its own circuit in the central unit (1) . 1Q. An installation according to claim 9, c h a r a c t e r i ¬ s e d in that said circuit. |
| 10. | in the central unit (1) includes a lightemitting diode (9A,9B) or other indicating member and that a part of said circuit containing said indicating member can be connected in parallel with other indicating circuits, preferably containing a soundgenerating means (10) . |
| 11. | An installation according to one or more of the preceding claims, c h a r a c t e r i s e d in that the central unit (1) is connected to, or includes two voltage units (11,12) which can be brought into function to supply either a sen¬ sing means (3) and its circuit in the central unit (1) , or an action member (5) , with voltage, both voltages being direct voltages and having different polarity, the voltages from the central unit (1) being transmitted via twoway wiring to a distributing unit (2), preferably arranged in the vicinity of one or more sensing means (3), said distri¬ buting unit (2) having a first, a second and a third termi¬ nal, where the first and the second terminals are connected one to each of the two wires in said twoway wiring, where the first terminal and the second terminal are connected to one or more sensing means (3) and where the first and the third terminals are connected by means of a rectifier. |
| 12. | An installation according to claim 11, c h a r a c t e r i¬ s e d in that the second terminal and the third terminal are connected to one or more action members (5) such as mines, illumination units or the .like, the voltage being applied on the first and the second terminals being 'inverted in rela¬ tion to the voltage applied on the second terminal and the third terminal. |
The present invention relates to a surveillance installation. In public places with a large through-flow of people TV cameras are generally used, connected to a surveillance centre where an observer sits and watches events. This is an efficient but extremely expensive method. For sur- veillance of areas where only a few people normally pass it is generally advisable to close off the area by means of a barrier or signs stating that entry is not permitted or is only permitted at certain times.
The present invention relates to an installation for surveillance of an area of the latter type. It is thus important that persons coming into contact with the installation are not in any way injured thereby. This is enabled by the invention by the provision of a manned or unmanned central unit which receives information if anyone is at the periphery of the area. The central unit is electrically connected to a number of sensing means located along the periphery of the area. Each sensing means is provided with one or more sensitive members which, when activated, alter the elec¬ trical state in the current circuit including the sensing means and said central unit. The sensitive member may constitute a wire, a net or the like which may either be placed on the surface of the ground or be suspended.
According to an advantageous embodiment the sensitive member is provided at one end with a magnet loosely applied on the sensing means and retained there by an attraction member which may consist of a strip of ferrometal. If the sensitive member is touched the magnet is easily dislodged and the electrical state in the above-mentioned current circuit is thus altered. Said magnet might, for instance, influence a circuit breaker or switch so that, in the absence of the magnet, a resistor is short-circuited.
It should be evident that the magnetic force of the magnet at the sensing means can be controlled by varying the distance between the magnet and the unit in the sensing means to which the magnet is attracted.
Electric current is transmitted between the central unit and a sensing means through a two-way wire. Both direct and alternating current are suitable for the purpose.
According to an advantageous embodiment of the present invention the Installation can also be used to initiate action members of various types. Such action members may consist of a tape-recorder providing Information as to the cause of the trespassing. Other examples of action members are search-lights or a unit emitting a smoke screen. For military appli¬ cations the action member may consist of a mine or a unit emitting toxic gas.
To enable the installation to be used for both gathering information and taking action it Is advisable to use two different direct voltages. The same wire connections used for the sensing means can then also be used for the action members. Each sensing means, and possibly also the central unit,, should include a rectifier. This enables the two. direct voltages to
» be pole-inverted with respect to each other, one direct voltage only cooperating with the sensing member and the other direct voltage only cooperating with the action member.
The two direct voltages may have the same or different values. In some cases it has proved advistable for one voltage to have low value and the other high value.
Further characteristics of the present invention are revealed in the following claims.
The present invention will be described in more detail with reference to the accompanying drawings showing one embodiment thereof.
The drawings show in
Figure 1 a wiring diagram for an alarm and control centre with a distribution unit,
Figure 2 a wiring diagram for a non-activated sensing means,
Figure 3 a section of a sensing means,
Figure 4 a see-through view of an embodiment of a sensing means,
Figure 5 a wiring diagram for an installation in non-activated state, Figure 6 a wiring diagram for an installation when triggered
Figure 7 a wiring diagram for an installation when triggered but with the buzzer disconnected,
Figure 8 a wiring diagram for an installation with an action member connected and Figure 9 block diagram over a complete installation.
Figure 1 shows an alarm and control centre 1 connected to a distribution unit 2. A sensing means and an action member, to be described in more detail In the following, can be connected to the distribution unit. The distribution unit 2 is connected to the alarm and control centre 1 by two leads. One of these leads includes a circuit with a light-emitting diode 9A, two rectifiers 23A and 24A, a resistor 21A and a three-way switch 15A. A buzzer 10 can also be connected in parallel tα this circuit. One or other of two direct voltage sources 11 and 12 can be connected to the two leads by means of circuit breakers 17, 18 and 19. The distribution unit 2 is provided with three connections, namely two outer connections and one intermediate connection. The two outer connections are joined together by a rectifier 16. The intermediate connection is connected to one of the two wires to the alarm and control centre, and the other wire from the alarm and control centre 1 is connected to one of the outer connections. A sensing means is connected to the intermediate connection and one of the outer connections and an action member is connected to the other outer connection and the intermediate connection.
A number of distribution units 2 are connected to the central alarm and control unit 1 , each distribution unit having its own circuit consisting of the units 9, 15, 21, 23 and 24.
Figure 2 shows a wiring circuit for a sensing means containing two switches 6A and 6B. The switches are actuated by magnets 7A and 7B,
respectively, and each switch is enclosed in a protective gas tube. The two switches are used to short-circuit a resistor 8. A practical embodi¬ ment of a sensing means is shown in Figure 4 revealing two pockets for the magnets 7A and 7B, the pocket for magnet 7A being designated 13. The pocket is located above the switch 6A which the magnet is to actuate. Below each magnet is a ferrometalllc unit which attracts the magnets 7A and 7B. When a magnet is in place in its pocket, the contact tongue assumes the position shown to the left in Figure 4 and, in the absence of the magnet, the position shown for the righthand switch.
Figure 3 shows an embodiment of a switch with associated magnet. The force with which a magnet is retained in the sensing means can be controlled by making the ferrometalllc strip adjustable in relation to a magnet placed In the pocket.
In a sensing means of the type just described, each magnet may have an eye " connected to a cord or net, both cord and net being either suspended or ' placed loose on the ground, preferably in such a manner as to be difficult to detect. The magnetic force shall be sufficient to remove the magnet without the person coming into contact with the cord or net being aware that he has encountered an obstruction.
Figures 5-8 describe a chain of events from alarm to action for an instal¬ lation comprising a distribution unit 2, a sensing means 3 and an action member 5. An installation comprising a larger number of sensing means and action members would function in exactly the same manner. The relevant current circuits have been indicated in thicker lines in the drawings.
The figures show a central alarm and control unit 1 connected to a distri¬ bution unit 2A to which are connected a sensing means 3A and an action member 5A. Figure 5 shows a situation in which current is supplied from a voltage source 11, this being of any size. However, it is probably advisable for this source to supply low voltage. A three-way switch 15A is in the position shown in the figure. A faint lamp in the form of a light- emitting diode 9 indicates if the sensing member 3A is correctly con¬ nected. Should a person tread on the cord or net connected to the magnet
7A, this magnet will be dislodged from the sensing means, whereupon the switch will assume the position shown in Figure 6. This Figure shows clearly that removal of the magnet has caused the resistor 8 to short- circuit so that the light-emitting diode receives higher voltage and shines more brightly. An operator in the alarm and control centre can immediately see that someone is In the vicinity of the sensing means 3A. At the same time as the light-emitting diode is caused to shine more brightly, a buzzer 10 or some other means generating sound is also acti¬ vated. If the three-way switch 15A is placed in its intermediate position (Figure 7) the buzzer 10 will be disconnected. The installation is now ready to initiate the action member 5A. If the action member 5A is to be initiated the three-way switch 15A must be brought to the position shown in Figure 8. The switch 17 must then be brought to its righthand position so that the distribution unit 2A is supplied with direct voltage from the source 12 where the direct voltage is pole-inverted in relation to the direct voltage supplied earlier. The existence of rectifiers 16 and 25 ensures that the pole-inverted direct voltage will be supplied only to the action member 5A. The action member 5A may consist of a compact little unit containing 'tape-recorder and loud-speaker. Alternatively, the action member may consist of a searchlight or any other suitable means, or it may even consist of a unit emitting a smoke screen or toxic gases. A water spray could also be initiated in this way. It Is also feasible to connect a number of sensing means in series or in parallel. The same applies to the action members which may be connected in parallel or in series. A combination of both series and parallel connection is also possible.
Initiation of the action members can also be performed automatically without manual intervention. The advantage of manual intervention is that undesired initiation of the action members can be prevented.
After initiation of an action member, all switches are moved to the positions shown in Figure 5 and dislodged magnets are returned to their pockets.
It should be evident that each sensing means may be provided with more than two magnets. Furthermore, each magnet may be connected to one or more cords or one or more nets.
Figure 9 shows an example of how an area is screened off with the aid of a number of sensing means. Four cables lead from the alarm and control unit 1 to four branch units 14A, 14B, 14C and 14D. Distribution units are connected to each branch unit. Two-way wiring cables lead to each distri¬ bution unit, each cable to a branch unit thus containing a number of wires corresponding to the number of branch units plus one extra. In the top righthand corner of Figure 9 is a distribution unit 2A to which a sensing means 3A is connected via a sensitive member 4A. In the lower righthand corner are two sensing means, designated 3B and 3B' , which are series- connected. The sensing means 3B is provided with a sensitive member 4B and the sensing means 3B' with a sensitive member 4B' . The lower lefthand corner of the figure shows a distribution unit 2C to which are connected two sensing members 3C and 3C . The upper lefthand corner of Figure 9 shows that the action members 5 can be both series and parallel s -connected, •two series-connected action members 5D and 5D' * and one parallel-connected action member 5D' ' being shown.
The concept of activating two different members by means of different, pole-inverted direct voltages, used for the sensing means and action member, respectively, is generally applicable and can be utilized in other installations where two different members are to be actuated using only direct voltage.
The sensing means utilized in the present invention can be used in Instal¬ lations where mechanical interference is to effect an alteration in a current circuit.
In the foregoing there has been described a sensing means 3, which causes an indication at a ecanical damage to wires,cords, net and the like. The indication is caused by the sensing means allowing a higher value of the current to pass through the same after a damage, said change in current can also be obtained by
not mechanical means. Thus the means can consist of microphones which feel vibrations in the ground or sound appearing at the sensing means 3. It is also possible that the supply means of the sensing means can be reacted by light of different frequences The supply means can emit light and receive light.
The control unit can have control units, which at change in cur¬ rent value at a sensing means immediately connect the higher voltage, which release the action means. In last mentioned case it ought to be suitable to use a relay which at increasing current from the sensing means attract the relay so that the higher D.C. voltage is supplied to the action member 5.