EP0018619B1 - Security arrangement with at least one wire rope net for protecting objects situated behind it - Google Patents

Abstract

1. Safety installation for saving objects situated behind the installation from rockfalls, avalanches or other dangers connected with mechanical actions on the safety installation, comprising at least one wire rope net and supporting means for propping or suspending the wire rope net, characterized in that the wire rope net (1; A-M) consists at least partly of wire rope (7, 8; 30, 31) having in its core at least one insulated electrical conductor (15, 16), the electrical conductor or conductors being connected to an electrical warning device (4; 35) responding and actuating an alarm system (5; 36) already below the loading limit of the whole installation in response to sudden changes, caused by mechanical actions, of the electrical properties of the line-system formed by the electrical conductor or conductors within the wire rope net or nets.

Description

The invention relates to a security system for securing objects located behind the same against stone chips, avalanches or other hazards associated with mechanical effects on the security system, with at least one wire rope network and support means for supporting or suspending the wire rope network.

Security systems of this type, in particular against falling rocks and avalanches, have been known for a long time and have generally proven themselves very well. Of course, it is clear with all of these security systems that they can only fulfill their security function within the framework of the technical conditions of the system, that there is an upper limit of the load capacity of such a system, which, if exceeded, will damage the system and therefore under unfavorable circumstances can no longer fulfill its security function. This upper limit value of the load capacity is of course freely selectable in principle, but since, on the other hand, the technical effort for the system becomes greater, the higher the limit value of the load capacity is applied when designing the system, this limit value is usually not at the upper limit what would be technically feasible, but it is tailored to the local conditions at the installation site of the security system. These local conditions are first of all - since such safety systems are set up at places where there is a risk of falling rocks or avalanches or, more correctly, at places where falling rocks or avalanches have occurred several times - the experience with the previously falling rocks or avalanches and In addition, of course, the shape and nature of the terrain in the area between the triggering location and the security system such as average slope, ground conditions and distance between the triggering location and the security system and, in the case of avalanche security systems, additional maximum snow thickness, slope exposure and sliding factor. As a rule, the procedure is such that the upper limit of the resilience of the safety system is many times greater than the maximum load resulting from previous experience and still a considerable safety factor higher than that resulting from terrain, etc., theoretically under the most unfavorable Choosing the maximum load that might result, but since it is known that natural events are not absolutely foreseeable in their strength, it still happens here and there that safety systems cannot withstand extremely strong rockfalls or avalanches and are either severely damaged by them or even collapse. Now, almost all of these security systems are intended for property security, whereby the objects to be secured are very often roads, track systems and other traffic routes in addition to buildings and other fixed facilities, and particularly in the case of traffic routes secured with such security systems, extremely strong rock falls or avalanches, which the security system is not up to and which therefore penetrate into the traffic route, is known to be a latent danger not only at the moment of decline but also after it is removed from the traffic route because the vehicles moving on the traffic route often do not arrive in time before the Descent point of the falling rocks or the avalanche can be stopped and there are no alternatives to railways anyway, and there are generally also no opportunities on the mountain roads, which are mainly at risk of falling rocks and avalanches; In addition, mountain roads are usually very winding and therefore confusing, which increases the risk of late detection of falling rocks or avalanches on mountain roads. But even with buildings and other fixed facilities secured with such security systems, damage to the security system due to extremely strong stone chips or avalanches is a latent danger, especially if the security system is still able to withstand the extremely strong stone chips or Stopping an avalanche, but being damaged so badly that it no longer offers adequate protection for subsequent rockfalls or avalanches. Experience has shown that the effectiveness of a security system can be relied on if it has so far always met the requirements, so that e.g. in the event of falling rocks or an avalanche at night, wait until the next morning to check the security system for any damage, and this can of course be fatal if the security system is severely damaged in the event of a further falling rocks or an avalanche on the same night be because the second decline may then trigger the first extremely strong decline, which is initially stopped by the security system. It does not always have to be negligence with regard to checking the security system in the game, because in many cases the buildings and fixed facilities to be secured are uninhabited and are also in uninhabited areas, so that the decline of stone chips or avalanches is not immediately noticed . The same naturally also applies to secluded and little-used traffic routes secured with such security systems, just as the previously discussed case of severe damage to such a security system which has not yet led to collapse naturally also represents a latent danger for traffic routes secured with it.

For the aforementioned reasons, the security of the objects secured with security systems of the type mentioned at the outset could be significantly increased if damage to such a security system immediately triggered the alarm at all locations in danger, as well as at the locations responsible for eliminating the damage and for automatic locking of one with the security would lead to a secured traffic route.

The invention was therefore based on the object of providing a security system of the type mentioned, in which an alarm is triggered immediately in the event of substantial damage to the system.

According to the invention, this is achieved in a security system of the type mentioned at the outset in that the wire rope network consists at least in part of wire rope, in the core of which at least one insulated electrical conductor is arranged, and in that the electrical conductor (s) is connected to an electrical warning device which Even below the load limit of the overall system, it responds to sudden changes in the electrical properties of the line system formed by the insulated electrical conductors within the wire rope network (s) caused by mechanical influences and actuates an alarm system.

The load limit of the overall system is considered to be the limit above which the overall system no longer withstands the mechanical action mentioned on the security system. Individual parts of the system can, e.g. in the case of staggered wire rope nets, without being loaded beyond the load limit.

Systems of a type other than those mentioned at the outset have already become known, which comprise warning devices of the same type as the present security system and are also primarily intended to protect against stone chips, e.g. from the magazine "Revue Generale des Chemins de Fer", vol. 90, Apr. 71, pp. 296/297, u. Vol. 96, Dec. 77, pp. 659/660, but these known systems have the fundamental lack of concept that they do not secure the objects to be protected against the danger but only indicate the occurrence of such a danger and the source of the danger is practically unhindered let happen. Thus, in the installations on mountain slopes known from the above-mentioned magazine, alongside railway roads and also over the railway roads, wire networks are tensioned, which are however not able to stop a rock fall, but which only register the occurrence of the rock fall as part of the aforementioned warning device and then Trigger alarm and thus automatically block the section of the route concerned. However, the rock fall itself falls on the railway roads and blocks the route until clearing, not to mention that it necessarily leads to the accident of trains that are at the moment of the rock fall at a distance below the braking distance of the train from the place of the rock fall and therefore can no longer be braked in time. One cannot therefore speak of security systems in these known systems, although these are often, e.g. are also incorrectly referred to in the aforementioned magazine, but these known systems are only warning systems which are not suitable for actually securing the objects behind them. The same applies to the z. B. from FR-A-7 737 521 and GB-A-1 278 646 known warning systems in the form of objects to be protected such as Nuclear research facilities, ammunition depots or other military installations surrounding wire mesh fences with the same type of warning device as the present security system, because these systems too cannot prevent or at least significantly hinder the illegal entry into the fenced area, but only indicate such an intrusion when the alarm is triggered but the intrusion per se or the cutting of the wire fence required for this no greater resistance than ordinary chain link fences. The lack of design is here in principle the same as in the railway warning systems discussed above, namely that due to the derivation of the warning criteria from damage to the warning system for the purpose of the functioning of the system, such damage has been deliberately made possible or relieved by a correspondingly light structure, which in There is a stark contradiction to the security function actually intended for the system. As a result, real security systems of the type mentioned at the outset have so far only become known in connection with security against falling rocks, avalanches, etc., and these have the disadvantages already discussed at the beginning, which are eliminated with the present security system.

The main advantage of the present safety system is that, in contrast to the known systems mentioned above, it does not have the mentioned lack of design but rather fulfills both the safety function intended for it and an additional warning function, the warning function not being limited to overloading the system and causing damage as a result can detect loads below the upper load limit. Another advantage of the present safety system is that the additional technical expenditure for the actual means for determining damage to the safety system, namely for the electrical conductors in the wire cables, is negligible and nevertheless, with the aid of these simple means which cause almost no additional work, any damage to any one Any point of the wire rope network or its suspension can be determined and that also the warning device and the alarm system can be very simple and - which is important in the present case - be robust and therefore cause no significant additional effort; in the simplest case, the warning device can consist of a single relay and the alarm system can consist of a simple bell. The only significant additional effort for the present security system arises from the connection between the security system and the location of the alarm system, which is usually relatively far away, provided that you do not want to rely on a radio connection, but this additional effort is system-related, i.e. it occurs in any case if damage to the security system is to trigger an alarm at a distant location.

In the present security system, the individual wire rope networks can be advantageous from one be formed single continuous wire rope, in the core of which an insulated electrical conductor is arranged. The wire rope can expediently form the wire rope network in the form of two intersecting meandering lines, through which the wire rope passes one after the other, or in the form of sections in each case at a 45 ° angle to the sides of an essentially square laying frame from base to base of the laying frame running and at each base point angled at about a right angle or in other, for example to form a wire rope network with rhombic meshes laid and mechanically connected at the crossing points and possibly also intertwined. In such a construction, a single continuous wire rope is preferably applied to the electrical conductor arranged in the same with a quiescent current which is suddenly interrupted in the event of an overload break in the wire rope network and thus in the said continuous wire rope and thus thus a break in the electrical wire arranged in the core of the wire rope and the warning device connected to the conductor and supplying it with the quiescent current then actuates the alarm system when the quiescent current is interrupted by one of the wire cable networks of the security system. If the safety system consists of several such wire ropes, each formed by a continuous wire rope, then the electrical conductors arranged in the wire ropes forming the individual wire rope nets can advantageously be connected in series, this series connection being acted upon by a quiescent current which, in the event of an overload breakage of one of the wire rope nets and thus the wire rope forming this wire rope network and thus a break in the electrical conductor arranged in the core of this wire rope is suddenly interrupted, and the warning device actuates the alarm system when the quiescent current is interrupted. However, each wire cable network can of course also have its own closed circuit, which can be advantageous for locating the breaking point.

However, in the event of an overload breakage of a wire rope provided with an insulated electric conductor in its core, the electric wire which has also been torn at the break point may come into contact with the wire rope at both ends of the break point, although this case is not very likely in itself is because, as a rule, when an insulated electrical conductor is torn, one of the two ends of the conductor at the tear point remains covered by the insulating sheath that forms the insulation and only at the other end of the conductor does a piece of uninsulated conductor protrude from the torn insulating sheath, and thus usually only one of the both ends of the conductor can come into contact with the wire rope at the breaking point. In the unlikely, but nevertheless possible and therefore not excluded, case that the conductor comes into contact with the wire rope at both ends of the break point, there is now the possibility that the quiescent current will not be interrupted despite the rope break and the associated conductor break , and that is when the conductor, before it finally breaks, comes into contact with both ends of the wire rope at the breaking point and this contact is maintained even after the conductor has broken at both ends of the broken wire rope. Such a possibility would be e.g. cannot be ruled out if the insulating jacket of the conductor is squeezed off the conductor during the rope break. In this case, the closed circuit would then run at the breaking point via the wire cable network, and the warning device would in any case not respond to the criterion "interruption of the closed circuit" despite the broken cable, because the closed circuit is never interrupted either during the broken cable or after it. In order to ensure a reliable response of the warning device in the event of a cable break even in such cases, it is necessary to design the warning device in such a way that it also responds to an electrical connection between the wire cable and the electrical conductor. This can advantageously be achieved in that there is an electrical voltage between the insulated electrical conductor and the wire rope and the warning device actuates the alarm system even when current flows from the electrical conductor to the wire rope, in particular in the event of a short circuit between the electrical conductor and the wire rope. However, it must be mentioned that this additional safety measure of an additional no-load circuit with the response criterion "circuit closure via a connection between the electrical conductor and wire rope" in addition to the response criterion "circuit breakage of the closed circuit running over the electrical conductor" in any case if in the warning device to determine Interruptions of the quiescent current, a relay or flip-flop switching to the alarm system even in the event of short-term interruptions of the quiescent current and which remains in this switch position even after the interruption, is hardly ever to be used in practice because the probability for the case theoretically discussed above is that the quiescent current is not interrupted at all even during the rope break, is only extremely small; because as a rule, in the already very unlikely case that after a rope break both conductor ends come into contact with the corresponding wire rope ends at the breaking point, during the rope break the contact of at least one of the two conductor ends with the corresponding wire rope end is at least briefly interrupted, and the resulting short-term quiescent current interruption is sufficient for switching over to alarming in the case of the relay or toggle switch mentioned above.

In a preferred embodiment of the present safety system, the wire rope network is composed of two wire ropes, in the core of each of which an insulated electrical conductor is arranged, and the two wire ropes are preferably arranged to form the wire rope network so that the two wire ropes intersect at each node of the wire rope network. The two wire ropes can expediently form two in order to form the wire rope network crossing meandering lines, each of which is traversed by one of the two wire ropes, or in other laying patterns leading to a wire rope network with square or rhombic meshes and mechanically connected at the crossing points and possibly also intertwined. This form of training is particularly advantageous if the wire rope network is suspended at its four corners via rope connections, because in this case the four rope connections for hanging the wire rope network can be formed directly by the four rope ends of the two wire ropes and thus the suspension of the wire rope network without electrical Interconnections at the network corners can be included in the security system, e.g. by connecting each of the two wire cables of the wire cable network to the warning device with its own closed circuit, so that at least one of the two closed circuits is interrupted if the network breaks or its suspension. As an additional safety measure, there may advantageously be an electrical voltage between the electrical conductor of each of the two wire ropes in the relevant wire rope or wire rope network and between the electrical conductors of the two wire ropes, the warning device when current flows from one or both electrical conductors to the wire rope network and when the current flows from one of the electrical conductors to the other, in particular in the event of a short circuit between the wire cable network and one or both electrical conductors and in the event of a short circuit between the two electrical conductors, the alarm system is actuated.

In the aforementioned preferred embodiment of the present safety system, however, the electrical conductors of the two wire cables can also advantageously be connected in series and acted upon by a quiescent current which occurs in the event of an overload break in the wire cable network and thus in the event of breakage of at least one of the two wire cables and thus a break in the electrical conductor arranged in the core of the wire cable concerned is suddenly interrupted; in this case the warning device actuates the alarm system when the quiescent current of one of the wire cable networks of the security system is interrupted. This series connection of the electrical conductors of the two wire ropes of the wire rope network is of course also possible in the above-mentioned case in which the wire rope network is suspended from the four rope ends of the two wire ropes, because in this case too, if the network is torn or suspended, the through the series circuit flowing quiescent current interrupted. Furthermore, as an additional safety measure, an electrical voltage can of course also advantageously be present between the two electrical conductors connected in series and the wire cable network in such a series connection of the electrical conductors of the two wire cables of the wire cable network, the warning device then being designed such that it is not only used for one Interruption of the quiescent current flowing through the series connection, but also when the current flows from one of the two or two electrical conductors to the wire cable network, in particular in the event of a short circuit between the cable network and one or both electrical conductors, the alarm system is actuated.

If the security system comprises a plurality of wire rope networks which, in accordance with the preferred embodiment mentioned above, are each formed from two wire ropes, in the core of which one insulated electrical conductor is arranged, then the electrical conductors arranged in the wire ropes of the wire rope networks can advantageously be formed into a first and a second Be connected in series so that each of the two series connections of each wire rope network detects one of the two wire ropes or the electrical conductors arranged therein. The two series circuits can form two separate quiescent circuits or can also be connected in series to form a common quiescent circuit comprising both series circuits. In the former case, as an additional safety measure, there can advantageously be an electrical voltage between each of the two series circuits and the wire cable networks and between the two series circuits, the warning device not only when one of the two closed circuit circuits is interrupted, but also when current flows from one or both series circuits to the cable network and when the current flows from one of the two series connections to the other, in particular in the event of a short circuit between the wire cable networks and one or both series connections and in the event of a short circuit between the two series connections, the alarm system is actuated. Preferably, however, the two series connections are connected in series and are supplied with a quiescent current which is suddenly interrupted in the event of an overload breakage of one of the wire rope networks and thus of at least one of the wire cables forming this wire rope network and thus a break in the electrical conductor arranged in the core of this wire rope, and that Warning device actuates the alarm system when the quiescent current is interrupted. As an additional safety measure, there can advantageously be an electrical voltage between the two series connections connected in series and the wire cable networks, the warning device not only in the event of a break in the quiescent current but also when current flows from one of the two or two series connections to the wire cable networks, in particular in the event of a short circuit between the wire cable networks and one or two series connections, the alarm system actuated.

If the present security system comprises several wire rope networks, it can also be advantageous if a separate response circuit with an assigned response element is provided in the warning device for each of the wire rope networks and the alarm system, when one of these response elements responds, indicates in addition to the alarm system which one of the response elements has responded or on which of the wire rope nets the alarm-causing damage has occurred. For example, each wire cable network can have its own closed circuit for this purpose and, as a response device in the warning device, a relay or toggle switch which switches over to alarm when the current is interrupted device and be used to transmit the response of this response organ from the warning device to the alarm system, a separate frequency assigned to the relevant cable network. Such a display of the damaged wire rope network (s) is advantageous in addition to respiratory protection, especially for the disaster relief service or the bodies responsible for the repair of the damage, because this immediately gives an idea of the extent of the damage to the security system (damage to one or more Wire rope networks) and the current danger situation (location of the damaged wire rope network (s) within the security system) and can make the necessary decisions immediately. For example, an immediate disaster response would not be absolutely necessary if one of the wire rope nets in a safety system built in a staggered manner in the form of several network groups arranged in a row was damaged, because this would require an immediate inspection and then a normal repair by a construction team be enough.

In general, in the present safety system, wire ropes should also be expediently provided for suspending or fastening the wire rope nets to the support means mentioned at the beginning, in the core of which at least one insulated electrical conductor connected to the warning device is arranged, so that one of these wire ropes is broken or damaged Alarm is triggered. Preferably, the quiescent current or the voltage to the electrical conductors arranged within the wire ropes forming the wire ropes are supplied via the insulated electrical conductors in the wire ropes used to suspend the wire rope nets. In this regard, it is particularly advantageous if, as already explained in connection with the preferred embodiment, the rope ends of the wire rope or wires forming the wire rope net can be used to suspend the wire rope nets.

In some cases, it can finally be advantageous if the warning device of the present safety system not only detects damage to the wire rope network or networks of the security system, an interruption of the quiescent current flowing through the conductors into the wire cables forming the wire rope networks, or a short circuit of the between These conductors and the wire ropes or wire rope nets have resulted in voltage, but also on minor damage such as Strains beyond the elastic range at one or more points of the wire rope network (s) or, for example, local deformations of the rope cross-section of the wire ropes forming the wire rope nets and to other overloads of the safety system, which do not yet lead to the breakage of one of the wire ropes forming the wire rope nets , appeals. For example, rockfalls and avalanches can be determined in this way, which are caught by the security system without causing serious damage to the security system, and such findings are important inasmuch as stone chips or avalanches captured represent a basic load of the security system, which can withstand the load for subsequent rockfalls or Avalanches are reduced and therefore the risk of overloading or collapse of parts of the system in the event of subsequent rockfalls or avalanches may be considerably increased. The detection of stone chips or avalanches that have been caught is therefore also a signal to inspect the system and, if necessary, to remove the basic pollution mentioned. In addition, e.g. In the case of a security system to secure a traffic route, a flashing light is switched on at a warning sign indicating the risk of falling rocks or avalanches, or other measures are taken to reduce the risk for the users of the traffic route, during the period in which the increased risk exists. It is therefore particularly advantageous for remote security systems that are not constantly under surveillance if the warning device responds not only to an interruption of the above-mentioned quiescent current or short-circuit of the stated voltage but also to sudden, significant changes in the absolute values of these quantities and, if such changes occur, without immediate response The following closed-circuit current interruption or voltage short-circuit in the alarm system triggers a pre-alarm that indicates damage and overstressing of the security system, which have not or have not yet led to a closed-circuit current interruption or a voltage short-circuit. Such a change in the absolute value of a voltage applied between the wire cable network and conductors via a high resistance occurs e.g. in the event of a strong mechanical impact on the wire rope network, in the form of a decaying voltage oscillation superimposed on the rest voltage. At the same time, however, there is usually a relatively small current oscillation of the current flowing through the conductors around the quiescent current value. The voltage oscillation is believed to be due to short-term changes in capacitance between the wire cable network and the conductor caused by the mechanical shock, while the current oscillation is likely to be caused by a change in inductance due to the displacement of the ferromagnetic material surrounding the conductor relative to the conductor in the mechanical shock. In any case, such superimposed electrical vibrations can be measured and can therefore be used as a response criterion.

If the security system at hand serves to secure traffic routes, in particular roads and track systems, then the alarm system should expediently include devices for automatically blocking the traffic route when an alarm is triggered. This further training has the essential advantage that the risk of collision with falling rocks or avalanches is practically completely eliminated.

• Fig. 1 ein besonders einfaches Ausführungsbeispiel einer Sicherungsanlage nach der Erfindung,
• Fig. 2 eine schematische Darstellung eines für Sicherungsanlagen nach der Erfindung verwendbaren Drahtseilnetzes mit zwei in Form von sich kreuzenden Mäanderlinien gelegten Drahtseilen, das an den vier Seilenden der beiden Drahtseile aufhängbar ist,
• Fig. 3 bis 7 ein weiteres Ausführungsbeispiel einer Sicherungsanlage nach der Erfindung zur Sicherung einer Bergstrasse mit schematischem Aufbau der Sicherungsanlage (Fig. 3), Warneinrichtung (Fig. 4 und 5) und Alarmanlage (Fig. 6 und 7).

The invention is explained in more detail below with the aid of the following figures using a few exemplary embodiments. Show it

• 1 shows a particularly simple embodiment of a security system according to the invention,
• 2 shows a schematic representation of a wire rope network which can be used for security systems according to the invention, with two wire ropes laid in the form of intersecting meandering lines and which can be suspended from the four rope ends of the two wire ropes,
• 3 to 7 another embodiment of a security system according to the invention for securing a mountain road with a schematic structure of the security system (Fig. 3), warning device (Fig. 4 and 5) and alarm system (Fig. 6 and 7).

In the embodiment of a security system according to the invention shown in Fig. 1, the system consists essentially of the wire rope network 1 with support means 2 and 3 for suspension thereof, the warning device 4, the alarm system 5 and the connecting line 6 between the warning device and alarm system.

The wire rope network 1 consists in detail of a relatively strong first wire rope 7 forming the network frame, a somewhat weaker second wire rope 8 forming the actual network, a connecting element 9 at each node of the network for connecting the intersecting sections of the wire rope 8, two spacers 10 on the lower corner loops 11 and 12 of the first wire rope 7 forming the net frame and a clamping member 13 for closing the corner loop 11 by non-positive connection of the rope ends of this first wire rope 7. The second wire rope 8 forming the actual net is in the form of a section in each case at a 45 ° angle to the sides of the network frame formed by the first wire rope 7 from one loop of the wire rope 7 to the next and at each loop point angled at approximately a right angle so that the actual network of a single continuous wire rope; namely the wire rope 8 is formed. The wire rope net 1 is suspended from the two hooks 2 with the two upper corner loops 14 of the first wire rope 7 and hooked into the two anchors 3 with the two lower corner loops 11 and 12 of the wire rope 7. Both the first wire rope 7 forming the net frame and the corner loops for hanging or hanging the wire rope net 1 as well as the second wire rope 8 forming the actual net is provided with an insulated electrical conductor arranged in the core of the wire rope. The electrical conductors 15 and 16 arranged in the wire cables 7 and 8 in FIG. 1 are visible at the cable ends led into the warning device 4, where the conductors 15 and 16 come out of the wire cables 7 and 8, respectively.

Within the warning device 4, the electrical conductors 15 and 16 are connected in series by the intermediate connection 17, and this series connection is connected via the main winding 18 and the contact 19 of the closed-circuit current relay 20 to the two-pole connecting line 6 between the warning device and the alarm system. The quiescent current relay 20 is also provided with a secondary winding 21, the number of windings and winding resistance of which coincide with that of the main winding 18 and which is preferably wound on the coil form of the relay together with the main winding in the manner of a bifilar winding. This secondary winding 21 is connected on the one hand to the connection between the main winding 18 and contact 19 and on the other hand to the two wire ropes 7 and 8 forming the wire rope network 1 or to the wires forming these wire ropes and poled so that when current flows through the secondary winding 21, the self-retention the relay-directed effect of the current flowing through the main winding 18 is canceled. Finally, the warning device 4 also contains a starter switch 22 connected in parallel to the contact 19 of the closed-circuit current relay 20 for bridging the contact 19 when switching on the safety system at the start of operation or switching it on again after eliminating damage which leads to the interruption of the closed-circuit current and thus to the relay dropping out 20 have led.

The connecting line 6 leads to the alarm system 5, which in the present case essentially consists of a bridge circuit 23 with a current source 24 above the one diagonal of the bridge and a bell 25 or a siren above the other diagonal of the bridge, in which a branch of the connecting line 6 and the connected to it warning device 4 and to this connected wire rope network 1 or from the resistor 26 shown in dashed lines in FIG. 1, the connecting line 6, warning device 4 and wire rope network 1 together, and the remaining bridge branches are formed by fixed resistors 27, 28 and 29. The size of the fixed resistors 27, 28 and 29 is selected so that the bridge circuit 23 is balanced when the safety system is in operation. The two fixed resistors 27 and 28 are preferably of the same size, and the size of the fixed resistor 29 corresponds to the sum of the winding resistance of the main winding 18 of the relay 20 and the line resistances of the two conductors 15 and 16 and the connecting line 6.

The safety system shown in FIG. 1 operates as follows: when the safety system is in operation, the bridge circuit 23 is adjusted according to the above statements and the voltage on the bell 25 is therefore zero, ie the bell 25 is switched off when the safety system is intact. In this case, the quiescent device 4 is supplied with a quiescent current via the connecting line 6, which is connected in series in the warning device 4 via the contact 19 and the main winding 18 of the quiescent current relay 20 which maintains this quiescent current, and then through the ones arranged within the wire cables 7 and 8 shaded electrical conductors 16 and 15 flows. If the wire rope network 1 is now damaged by stone chips, an avalanche or other mechanical effects and thereby one of the two wire ropes 7 or 8 or both breaks at one or more points, then the electrical conductor arranged in the relevant wire rope also tears at these points , and thus the quiescent current flowing through the series-connected electrical conductors 15 and 16 is generally interrupted. With this interruption of the quiescent current, the main winding 18 of the quiescent current relay 20 is de-energized, and thus the relay drops out and the contact 19 opens. With the drop of the relay 20 and the simultaneous opening of the contact 19, the closed circuit is finally interrupted and can not close again if both ends of the wire at the breaking point get in contact with the wire rope or the wire rope network after a short interruption of the closed circuit current and thereby the original point of interruption is bridged again. Only in the highly unlikely case already discussed at the beginning, in which no quiescent current is interrupted during the rope break, because the conductor at the rope break point has contact with both ends of the wire rope at the break point before its final tearing and this contact is maintained even after the conductor has torn, and in the likewise very unlikely case that both conductor ends at the rope break point already come into contact with the wire rope or the wire rope network after an interruption time of the quiescent current below the fall time of the relay 20, the quiescent current would continue to flow even after the rope break. In these cases, however, the secondary winding 21 of the closed-circuit current relay 20 comes into action, via which a voltage corresponding to the voltage drop across the main winding 18 is applied to the wire cable network 1 or the wire cables 7 and 8 relative to the conductors 15 and 16 connected in series. Because with the contact between the conductor and the wire rope at the breaking point in the aforementioned cases, this voltage is short-circuited or the circuit running through the secondary winding 21 is closed, and since the winding resistance of the secondary winding 21 is as large as that of the main winding 18, then flows through the Secondary winding 21 is a practically the same current as via the main winding 18, which virtually completely eliminates the magnetic field generated by the main winding 18 due to the reverse polarity of the secondary winding 21 and thus causes the relay 20 to drop. When the relay 20 drops, the contact 19 then opens, and the closed circuit is then finally interrupted in these exceptional cases. It should be mentioned in this connection that the same can also be achieved with a normal closed-circuit current relay which has only one main winding but no secondary winding; in this case, the wire ropes 7 and 8 or the wire rope network 1 in FIG. 1 would be connected directly to the connection between the main winding 18 and the contact 19, and in the case of the aforementioned short circuit the voltage applied between the wire rope network 1 and the conductors 1 and 16 would then be the Main winding 18 practically short-circuited and thus the relay 20 is also brought down. Furthermore, it should be mentioned that, of course, appropriate electronic relays can also be used instead of electromagnetic relays, which also has the advantage of significantly shorter switching times and thus the switching of the relay even in the case of only very brief interruptions in the quiescent current which are below the fall time of an electromagnetic relay brings with it. When using an electromagnetic relay 20 as in FIG. 1, the decay time can be reduced by making the winding resistance as large as possible or by making the ratio of winding inductance to winding resistance as small as possible; in any case, the winding resistance of the windings 18 and 21 should be substantially greater than the resistance of the conductors 15 and 16 connected in series and should be at least 10 times, preferably more than 100 times, the same.

In the alarm system 5, at the moment of the interruption of the quiescent current flowing via the connecting line 6 to the warning device 4, the adjustment of the bridge circuit 23 and thus the voltage zero via the bell 25 is canceled and a current is driven through the bell 27 via the resistors 27 and 29. so that it starts to ring and give the alarm.

It is essential in the security system shown in FIG. 1 that it can practically not be put out of operation, neither by damage to the warning device 4 or the connecting line 6 in the event of a catastrophe, nor by arbitrary interventions aimed at preventing the alarming; because even if the connecting line 6 is short-circuited at any point by damage to the line itself or the warning device 4 or also by an arbitrary intervention aimed at maintaining the quiescent current to prevent the alarm, the adjustment of the bridge circuit 23 in the alarm system 5 is canceled and thus triggered alarm. The same naturally also applies if the connecting line 6 breaks, which corresponds to an interruption in the closed-circuit current. The only way to put the security system out of operation by an arbitrary intervention would be to terminate the connecting line with a resistor corresponding to the winding resistance of the winding 18, but this possibility could also be prevented by already opening the bell 25 when the bridge adjustment is canceled for a short time, the switching relay switches on, because it is practically impossible to connect the simulation resistor at the same time as the connecting line 6 is disconnected from the warning device 4, and if one connects it just before or afterwards, this results in such a relay control the bell 25 for alarming briefly canceling the bridge adjustment of the bridge circuit 23. Due to the fact that the security system shown in FIG. 1 can practically not be put out of operation, this is also for securing objects against arbitrary or violent same illegal interference, e.g. in the form of a fence around the object to be secured with wire rope nets designed in accordance with the present invention.

Of course, in the safety system in FIG. 1, instead of the one wire rope network 1 shown there, a plurality of wire rope networks can also be provided, in which case the insulated electrical conductors arranged within the individual wire rope networks would then have to be connected in series, so that they all flow through the same quiescent current supplied via the connecting line 6. In addition, for example, for fences or gates made from such wire rope nets, the individual wire rope nets can also have a rectangular shape instead of the approximately square shape shown in FIG. 1, and finally it is also possible to construct an entire fence or an entire fence from a single, very elongated one To form wire rope net. For the construction of safety systems with a larger number of wire rope nets with electrical conductors connected in series, however, the structure of wire rope nets shown schematically in FIG. 2 with two wire ropes 30 and 31 laid in the form of intersecting meandering lines and a network frame 32 consisting of a ring-shaped wire is suitable closed wire rope a little better, because with such a construction of the individual wire rope nets the nets arranged next to each other to form a fence or gate can be connected much more easily; because, as shown in Fig. 2, the two wire ropes 30 and 31 forming the wire rope net begin at the two ends of one side of the net and end at the two ends of the opposite side of the net, so that when nets are arranged side by side, the conductors of the nets are in the same place wire ropes coming out of neighboring networks can be connected directly to one another. In addition, in the case of a construction as in FIG. 2, it is also possible to use the wire ropes coming out on one side of the network directly for the construction of the next neighboring network and in this way to build up a plurality of networks arranged next to one another with two continuous wire ropes.

1 that the warning device 4 can be further simplified there by omitting the relay 20 including the contact 19 and the start switch 22 and instead only the one in FIG. 1 via the contact 19 and the main winding 18 of the relay 20 connected to the conductor 16 pole of the connecting line 6 is connected to the conductor 16 via a large resistance relative to the line resistance of the series-connected conductors 15 and 16 and also to the connection point between this pole and the said large resistance, the wire cable network 1 or the wire ropes 7 and 8 are connected. The effect of this simplified circuit is almost the same as with the relay 20, except that in the case that is hardly possible in practice that after a cable break the conductor ends of the conductor torn at the break point come into contact again without also using the wire cable to come into contact, the alarm signal which begins with the tearing of the conductor is switched off again as soon as the conductor ends come into contact again at the breaking point; this is not possible with the circuit in FIG. 1 because there the relay 20 drops when the conductor is torn and the quiescent circuit is finally interrupted by the simultaneous opening of the contact 19. A further simplification of the circuit in FIG. 1 is still possible in the alarm system 5 if the voltage source 24 has a tap; in this case the fixed resistors 28 and 29 can be omitted and the pole of the bell 25 connected to this in Fig. 1 can be connected to this tap, but then the fixed resistor 27 must be selected so that the voltage above when the fuse system is in operation the bell 25 is zero. In this context, it should also be pointed out that an AC voltage source can of course also be used instead of the DC voltage source 24 in FIG. 1, but the power supply to the security system should expediently primarily come from a buffer battery built into the alarm system 5, which is constantly recharged from the network , so that the safety system does not fail in the event of a mains power failure. However, if the safety system should not only respond to serious damage such as a broken rope of the wire rope forming the system's wire rope networks, but already to minor damage or overloading of the system that does not yet lead to a rope break, then the warning device and the alarm system are somewhat more complicated to set up Security system in Fig. 1 required.

FIGS. 3 to 7 show an exemplary embodiment of such a security system which is already responsive to minor damage and overloading of the wire cable networks or their suspensions. This security system serves, as can be seen in FIG. 3, to secure the mountain road 33 against the penetration of stone chips falling in the gorge 34 into the road. For this purpose, a series of elongated wire rope nets A to M are staggered in the gorge 34 in front of Bergstrasse 33 in such a way that stone chips from the front nets A and M, B and L, and C and K are not absorbed but only with energy loss is guided into a kind of funnel, which is formed by the nets A to D and K to M and catches rockfalls of normal strength without any damage to the nets. In the case of very heavy stone chips, however, it can happen that the net D arranged at the bottom of the funnel breaks or collapses, in which case the nets E and I absorb the stone chips. To further increase security, a further group of networks F, G and H is arranged behind these networks E and I, but these are used at most in pronounced catastrophes. In such a funnel-shaped structure of a rockfall protection system, the rockfalls collected by the system accumulate at the funnel base, i.e. in front of the network D, and form a basic load on the network D and possibly also on the networks C and K, which determine the resilience of these networks for subsequent ones Reduces rockfalls and increases the risk of collapse in subsequent rockfalls, especially for network D. It is therefore important for those entrusted with the monitoring of the security system as well as the elimination of such basic loads and possible damage to be able to detect falling rockfalls, which are absorbed by the system without significant damage leading to the alarm, at the moment of the decline and then also in to be able to assess their course and, if necessary, their strength. For this purpose, the warning device 35 of the security system shown in the block diagram in FIG. 4 is designed in such a way that, firstly, it does not only respond to the response criteria already used in the security system in FIG. 1, but also to the abovementioned ones that occur in the event of strong mechanical impacts on the wire cable network Voltage vibrations of the voltage lying between the conductor and the cable network responds and secondly is provided with a separate response circuit for each of the networks A to M, which via a separate channel of an existing radio link between warning device 35 and alarm system 36 with an associated receiving circuit in the alarm system 36 in Connection is established. The structure of such a response circuit 37 is shown in the block diagram in FIG. 5 and the structure of one of these receive circuits 38 is also shown in a block circuit in FIG. 7. By means of the response circuits 37A to 37M assigned to the individual networks A to M, for each network separately rope break in the network or its suspension with the response criterion "interruption of the quiescent current flowing through the conductors in the wire cables forming the network and / or short circuit between one of these conductors and the wire cable network "and secondly strong mechanical impacts on the network with the response criterion" voltage fluctuations of the voltage between the conductor and the cable network exceeding a predetermined threshold value "and via the assigned channel of the radio connection mentioned between warning device 35 and alarm system 36 to the assigned receiving circuit in FIG Alarm system 36 is transmitted, and by means of the receiving circuits 38A to 38M assigned to the individual networks A to M, a separate display device 39 "Rope break in the network or its suspension" and a second display are provided for each network separately Direction 40 "Strong mechanical impacts on the network" is displayed if the corresponding response criteria are present in the assigned response circuit. The pairs of display devices 39 and 40 assigned to the individual networks A to M can advantageously be arranged in the same way as the networks A to M in FIG. 3 and consist of differently colored lamps, for example a red lamp for rope breakage in the assigned network and a yellow lamp for mechanical impacts on the assigned network. On a display panel constructed in this way, with lamp pairs arranged like the nets in FIG. 3, the entire situation in the event of a rockfall can be seen at a glance: the yellow lamps which light up on the panel indicate which nets the stone impact has hit, and possibly red lamps which light up mark damaged nets where either the net itself or its suspension is torn. From the number and position of the yellow lamps that are lit up, conclusions can be drawn about the strength and path of the stone chipping, and if the red lamps are lit up, it can be determined whether the yellow lamps of the nets arranged behind the damaged nets are lit or not, whether they are with the flashing red lamps marked damaged nets could not withstand the falling rocks or could stop them despite their damage. Finally, the lighting up of one of the two red lamps assigned to networks E and I, in particular in connection with the lighting up of one of the yellow lamps assigned to networks F, G and H, shows the acute danger of the stone chipping breaking through Security system and the lighting of one of the red lamps assigned to the networks F, G and H indicate such a breakthrough.

The mode of operation of the security system shown in FIGS. 3 to 7 can be explained on the basis of the mode of operation of the response circuits 37A to 37M and the receive circuits 38A to 38M described below on the block diagrams of these circuits shown in FIGS. 5 and 7: The one shown in FIG Response circuit 37 is connected with the connections 41 and 42 to the two ends of the insulated electrical conductor or the series-connected conductor of the assigned network and with the connection 43 to the wire cables of the assigned network. The voltage source 44 drives, via the high-resistance resistor 45, a quiescent current flowing through the low-resistance conductor or the series-connected conductors of the assigned network and, at the same time, applies a voltage across the high-resistance resistor 46 of the same size as that of the resistor 45 to the wire cables of the assigned network the conductor located within these wire ropes. In the normal case, the voltage drop across the resistor 45 is approximately + U and across the resistor 46 is zero if U denotes the level of the voltage of the voltage source 44. The input voltage of the diode circuit 47 to earth is therefore normally + U. If a cable break occurs in the assigned network, then the input voltage of the diode circuit 47 changes. There are the following options: If only the conductor arranged in the wire cable breaks at the breaking point breaks, but there is no contact between the conductor and the wire rope, then the quiescent current flowing through the conductor before the rope breaks is interrupted and the voltage drop across resistor 45 is zero; the voltage drop across resistor 46 remains zero since the conductor has not come into contact with the wire rope. The input voltage of the diode circuit 47 to ground is therefore zero in this case. If, on the other hand, if the cable breaks, in addition to the conductor tearing, there is contact between the conductor and the wire cable, via which the voltage source 44 can drive a current through the resistor 46, then the voltage drop across the resistor 46 and thus the input voltage of the diode circuit 47 to earth approximately - U. Finally, in the unlikely case discussed above in connection with FIG. 1, that the conductor at the rope breaking point comes into contact with both wire rope ends at the breaking point before his final tearing and this contact also after the tearing of the lei ters is maintained and the said quiescent current is therefore not interrupted either during or after the rope break, the voltage drop across the resistor 45 remains approximately + U, and across the resistor 46 there is a voltage drop of approximately -U to earth, so that the input voltage of the diode circuit 47 becomes almost zero towards earth. The input voltage of the diode circuit 47 to earth, which is normally + U, therefore becomes zero or negative in the event of a cable break in the assigned network, so that the diode circuit 47 is blocked in the assigned network in the event of a cable break and thus the one connected to the output of the diode circuit 47, for example Relay 48 in the form of a flip-flop changes from its normal 1 state to the 0 state. With this transition to the 0 state, the relay 48 switches off the generator 49, which in the normal case, that is to say if the assigned network is undamaged, outputs a fundamental frequency characteristic of the assigned network via the modulator 50 to the output line 51. The presence of this fundamental frequency on the output line 51 therefore indicates that the assigned wire rope network is intact, while a lack of this fundamental frequency on the output line 51 is the sign of a rope break in the assigned wire rope network or its suspension. Also connected to the output of the relay 48 is the inverter 52, which in the 0 state of the relay 48, that is to say in the event of a rope break in the associated network, outputs a current to the output line 53, while in the 1 state of the relay 48, that is in the case of an undamaged assigned network, does not deliver such electricity. The amplifier 37, the threshold circuit 55, the generator 56 and also the decoupling diode 57 are also provided in the response circuit 37 in order to determine strong mechanical impacts on the associated network, which do not result in a cable break in the network or its suspension. The input of the amplifier 54 is located above the resistor 46, through which a current flows when the voltage between the wire rope and the conductor of the associated network vibrates due to strong mechanical impacts on the network which is proportional to the voltage oscillation superimposed on the rest voltage between the wire rope and the conductor and causes a voltage drop corresponding to this voltage oscillation at the resistor 46. From the amplifier 54, the positive half-waves of the voltage oscillation dropping across the resistor 46 are amplified and fed to the threshold circuit 55, which, when a certain threshold value of the energy content of the amplified half-waves is exceeded, outputs an output signal which switches on the generator 56 and also via the decoupler diode 57 Output line 58 is supplied. When it is switched on, the generator 56 outputs to the modulator 50 a fixed frequency f _s with which the fundamental frequency f _o emitted by the generator 49 is modulated, so that the fundamental frequency and the two frequencies fo + obtained by the modulation are then on the output line 51 fs and f _o -f _s stand. The response circuit 37 is thus a total of at undamaged and no bumps Exposed to an associated network via the output line 51 the fundamental frequency f _o and the other two output lines 53 and 58 not in severe mechanical shocks on the associated network via the output line 51, the frequencies f _o, fo + fs and f _o -f _s and via the output line 58 said output signal of the threshold circuit 55 and via the output line 53 nothing, and finally in the event of a broken rope in the associated network or its suspension via the output line 51 either nothing or depending on the structure of the modulator 50 only the frequency f _s and via the output line 53 the current supplied by the inverter 52 and via the output line 58 the output signal of the threshold circuit 55. The output variables output via the output lines of the response circuits 37A to 37M assigned to the individual networks A to M are processed in the warning device 35 as follows: The output lines 51 of the response circuits 37A to 37M lead to a transmission device 59, which via a transmission device 59 with a transmission antenna 60 in derwarneinrichtung 35 and the receiver 61 with receiving antenna 62 in the alarm system 36 comprehensive conventional radio connection between the warning device 35 and the alarm system 36 transmits all the frequencies fed to it on the input side via the output lines 51 of the response circuits 37A to 37M on a carrier tape to the receiver 61 in the alarm system 36 the output side of which the receiving circuits 38A to 38M assigned to the individual networks A to M are connected. The output lines 53 of the response circuits 37A to 37M are interconnected, as shown in FIG. 4, and lead to the relay 63, which is designed, for example, in the manner of a flip-flop and is in the 0 state when the intact fuse system is in operation and in the 1 state changes as soon as a cable break occurs in one of the networks A to M or as soon as the inverter 52 outputs one of the response circuits 37A to 37M via lines 53 and 64 to the input of relay 63 and thus to the input resistance of relay 63 the required breakover voltage is generated for switching the same. With its transition to the 1 state, the relay 63 switches the signal systems 66 to "red" via the lines 65 and thus blocks the road section 67 of the Bergstrasse 33 which is at risk of falling rockfall. The output lines 58 of the response circuits 37A to 37M are, as shown in FIG 4 shows, also interconnected, and lead to the relay 68, which is designed, for example, in the manner of a flip-flop and which, when the safety system is in operation and intact and not subjected to shocks, is also in the 0 state and changes to the 1 state as soon as one the networks A to M receive a strong mechanical shock or as soon as an output signal is output from the threshold circuit 55 of one of the response circuits 37A to 37M via the assigned decoupler diode 57 and the lines 58 and 69 to the input of the relay 68. With its transition to the 1 state, the relay 68 switches via lines 70 to that on the Bergstrasse 33 turn signals 71 arranged in front of the signaling systems 66, which - possibly in connection with traffic signs indicating possible rockfall - draw attention to the increased danger due to falling rockfall and call for careful driving and increased caution when passing the section 67 of the rockfall. In the alarm system 36, as mentioned above, the receiving circuits 38A to 38M assigned to the individual networks A to M are supplied with the carrier tape transmitted from the transmitting device 59 to the receiver 61 via the radio connection mentioned. In the receiving circuit 38, from this carrier band fed to the input 72 of the receiving circuit 38, the frequency range of the lower sideband of the carrier frequency f, which contains the fundamental frequency f _o which is characteristic of the assigned network and which frequency (f, - f _o -f _s ) extends to the frequency (f, -f _o + f _s ), and the output signal of the bandpass filter 73 is then demodulated in the demodulator 74 and thus converted into the frequency range f _o ± f _s . From the output signal of the demodulator 74, the fundamental frequency f _o is then - if present - filtered out by means of the filter 75 and the frequency f _o -f _s by means of the filter 76. The output signal of the filter 75 is then fed to the inverter 77 rectifying on the input side, and further the output signals of both filters 75 and 76 are fed to the AND circuit 78 also rectifying the input side. On the output side, the inverter 77 only emits a signal if the fundamental frequency f _o , which is normally present, that is to say in the case of an undamaged associated network, is eliminated, i.e. when the generator 49 is switched off in the assigned response circuit or in the event of a rope break in the assigned network or its suspension, but also when the radio connection between the warning device 35 and the alarm system 36 is interrupted. A signal emitted on the output side by the inverter 77 is first of all given to the display device 39 already mentioned above, and secondly via the decoupler diode 79 and the output line 80 and the line 81 supplied acoustic alarm device 82 and causes the activation of the alarm device 82 - if it is not already in the switched-on state due to a corresponding signal from another receiving circuit - and also the switching on of the display device 39 and thus, for example, as already mentioned by lighting up a red lamp used as a display element, the display of the network in which the rope break occurred. The AND circuit 78 emits a signal on the output side when the frequency f _{o is} at its input connected to the filter 75 and the frequency f _o -f _s at its input connected to the filter 76, that is to say when generators 49 and 56 are switched on in the assigned response circuit or in the event of a strong mechanical impact on the assigned network, provided that this is still undamaged at the moment of the impact or has no rope break. A signal emitted by the AND circuit 78 on the output side is fed firstly to the display device 40 already mentioned above and secondly via the decoupler diode 83 and the output line 84 and the line 85 to the optical or likewise acoustic alarming device 86 which is provided for pre-alarming and effects this Switching on the alarm device 86 - if it is not already in the switched-on state due to a corresponding signal from another receiving circuit - and also switching on the display device 40 and thus, for example, as already mentioned by lighting up a yellow lamp used as a display element, the display of the network which was subjected to the strong mechanical shock. The display devices 39 and 40 of the receiving circuits 38A to 38M assigned to the individual networks A to M and also the two alarm devices 82 and 86 provided for the main alarm and pre-alarm can expediently be designed in such a way that they are switched on even if the output signal of the inverter causing the same is lost 77 or the AND circuit 78 remain switched on and can only be switched off manually by the monitoring personnel of the alarm system 36. Firstly, this has the advantage that the information provided by these devices cannot be lost before they have been noticed by the monitoring personnel, and secondly, with such a design, a short-term failure of the radio connection between warning device 35 and alarm system 36 can also be determined , because in the event of a failure of this radio connection, the inverters 77 of all the receiving circuits 38A to 38M, as a result of the loss of their input signal caused by the radio connection failure, send a signal to the respectively associated display device 39 and the alarming device 82 to activate these devices, so that an alarm occurs in the event of a radio connection failure is given and all the «red lamps» light up, and with the said training this state does not disappear immediately after a short-term radio connection failure but remains until it and thus the short-term radio connection a accident has been noted by the surveillance personnel of the alarm system 36; The surveillance personnel then manually reverses this state and, if necessary, takes the measures necessary to ensure that the radio connection is maintained.

Finally, it should also be pointed out that security systems according to the invention are not only suitable, for example in the form of fences, not only as in the above exemplary embodiments for protecting objects against natural events, but also - as also briefly indicated above - for protecting objects against arbitrary or violent illegal interventions or complete enclosures of the object to be secured with wire rope nets designed in accordance with the present invention. For example, a building to be secured can be provided with a fence which, in a manner similar to the security system in FIGS wire rope nets connected to the warning device and therefore not only allows the detection of an illegal intervention per se but also immediately reveals the approximate location of the fence at which the illegal intervention takes place and therefore enables targeted countermeasures. A similar result can also be achieved with a fence consisting of only a single, very elongated wire rope network or of a large number of wire rope networks, the insulated electrical conductors of which are all connected in series, by the warning device through the electrical conductor or the series-connected ones electrical conductor impulses are sent and reflections of these impulses returning to the starting point are determined and from the time elapsed between the transmission of the impulse and the reception of the reflected impulse the reflection point and thus the point of the illegal intervention is determined.

Claims (18)

1. Safety installation for saving objects situated behind the installation from rockfalls, avalanches or other dangers connected with mechanical actions on the safety installation, comprising at least one wire rope net and supporting means for propping or suspending the wire rope net, characterized in that the wire rope net (1; A-M) consists at least partly of wire rope (7, 8; 30, 31) having in its core at least one insulated electrical conductor (15, 16), the electrical conductor or conductors being connected to an electrical warning device (4; 35) responding and actuating an alarm system (5; 36) already below the loading limit of the whole installation in response to sudden changes, caused by mechanical actions, of the electrical properties of the line-system formed by the electrical conductor or conductors within the wire rope net or nets.

2. Safety installation according to claim 1, characterized in that the wire rope net (1) is formed by a single one through wire rope (8) having an insulated electrical conductor (16) in its core.

3. Safety installation according to claim 2, characterized in that the electrical conductor (16) carries a stationary current being suddenly interrupted with an overloading-rupture of the wire rope net (1) and thus of said through wire rope (8) and therefore consequently with a rupture of the electrical conductor (16) provided in the core of the wire rope, and the warning device (4) actuates the alarm system (5) with an interrupture of the stationary current of any wire rope net of the safety installation.

4. Safety installation according to claim 2 with a plurality of wire rope nets, characterized in that the electrical conductors provided in the wire ropes of the single wire rope nets are connected in series and this series connection carries a stationary current being suddenly interrupted with an overloading-rupture of one of the wire rope nets and thus of the wire rope forming this wire rope net and therefore consequently with a rupture of the electrical conductor provided in the core of this wire rope, and the warning device (4) actuates the alarm system (5) with an interrupture of the stationary current.

5. Safety installation according to one of the claims 2 to 4, characterized in that an electrical voltage is present between the insulated electrical conductor (16) and the wire rope (8), and the warning device (4) actuates the alarm system (5) also with a current flowing from the electrical conductor to the wire rope, particularly with a short-circuit between the electrical conductor and the wire rope.

6. Safety installation according to claim 1, characterized in that the wire rope net (A-M) is formed of two wire ropes (30, 31) each of which having an insulated electrical conductor in its core, preferably the both wire ropes, for forming the wire rope net, are arranged so that both wire ropes cross each other on each point of junction of the wire rope net.

7. Safety installation according to claim 6, characterized in that electrical voltages are present between the electrical conductor of each of the both wire ropes and the respective wire rope or the wire rope net and between the two electrical conductors of the both wire ropes, and the warning device actuates the alarm system with a current flowing from one or both of the electrical conductors to the wire rope net and with a current flowing from one of the two electrical conductors to the other, particularly with a short-circuit between the wire rope net and one or both of the two electrical conductors and with a short-circuit between the two electrical conductors.

8. Safety installation according to claim 6, characterized in that the electrical conductors of the both wire ropes (30,31) are connected in series and carry a stationary current being suddenly interrupted with an overloading-rupture of the wire rope net and thus with a rupture of at least one of the both wire ropes (30, 31) and therefore consequently with a rupture of the electrical conductor provided in the core of the respective wire rope, and the warning device (35) actuates the alarm system (36) with an interrupture of the stationary current of any wire rope net of the safety installation.

9. Safety installation according to claim 8, characterized in that additionally an electrical voltage is present between the both electrical conductors connected in series and the wire rope (A-M), and the warning device (35) actuates the alarm system (36) also with a current flowing from one or both of the two electrical conductors to the wire rope net, particularly with a short-circuit between the wire rope net and one or both of the two electrical conductors.

10. Safety installation according to claim 6 with a plurality of wire rope nets, characterized in that the electrical conductors provided in the wire ropes (30, 31) of the wire rope nets are connected together to a first and a second series connection in such a manner that each of the both series connections comprises, from each of the wire rope nets, the electrical conductor provided in one of the both wire ropes of that wire rope net.

11. Safety installation according to claim 10, characterized in that an electrical voltage is present between each of the both series connections and the wire rope nets and between the two series connections, and the warning device actuates the alarm system with a current flowing from one or both of the two series connections to the wire rope nets and with a current flowing from one of the two electrical conductors to the other, particularly with a short-circuit between the wire rope nets and one or both of the two series connections and with a short-circuit between the two series connections.

12. Safety installation according to claim 10, characterized in that the two series connections are connected in series with each other and carry a stationary current being suddenly interrupted with an overloading-rupture of one of the wire rope nets (A-M) and thus of at least one of the wire ropes forming this wire rope net and therefore consequently with a rupture of the electrical conductor provided in the core of this wire rope, and the warning device (35) actuates the alarm system (36) with an interrupture of the stationary current.

13. Safety installation according to claim 12, characterized in that additionally an electrical voltage is present between the two series connections connected in series with each other and the wire rope nets (A-M), and the warning device (35) actuates the alarm system (36) also with a current flowing from one or both of the two series connections to the wire rope nets, particularly with a short-circuit between the wire rope nets and one or both of the two series connections.

14. Safety installation according to one of the claims 1 to 3 and 5 to 9 with a plurality of wire rope nets, characterized in that a separate response- circuit (37) with a response member (48) belonging thereto is provided in the warning device (35) for each of the wire rope nets (A-M), and the alarm system (36) indicates with a response of one of these response members (48), additionally to the alarm giving, which one of the response members (48) has responded and at which one of the wire rope nets (A-M) therefore the damage causing the alarm happened.

15. Safety installation according to one of the claims 1 to 14, characterized in that also for suspending and/or fastening the wire rope nets (1) on said supporting means (2, 3), wire ropes (7; 30, 31) are provided each having in its cores at least one insulated electrical conductor (15) connected to the warning device (4; 35), so that alarm is caused also with a rupture or damage of one of these wire ropes (7; 30, 31).

16. Safety installation according to claim 15, characterized in that the stationary current and/or the voltage is fed to the electrical conductors (16) provided in the wire ropes (8) forming the wire rope nets (1) over the insulated electrical conductors (15) provided in the wire ropes (7; 30, 31) serving for suspending and/or fastening the wire rope nets (1).

17. Safety installation according to one of the claims 3 to 5, 7 to 9, and 11 to 16, characterized in that the warning device (35) responses not only to an interrupture of said stationary current and/or a short-circuit of said voltage but also already to sudden essential changes of the absolute values of these magnitudes and causes a pre-alarm in the alarm system (36) with an arising of such changes without an immediately following interrupture of the stationary current or short-circuit of the voltage, which pre-alarm indicates damages and over- loadings of the safety installation having not or not yet caused an interrupture of the stationary current or a short-circuit of the voltage.

18. Safety installation according to one of the claims 1 to 17 for saving traffic ways, particularly roads and track systems, characterized in that the warning device (35) and/or the alarm system comprise equipment (63-66) for automatically closing the traffic way (33) with an actuated alarm.

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