EP0073934B1 - Grate bar capable of triggering an alarm - Google Patents

Abstract

1. Grate bar (1) capable of triggering an alarm, with a hollow metal section (2) with at least one alarm wire (25) for the operation of an alarm device, the alarm wire (25) being placed in a glass body (26), which practically fills the entire hollow space of the bar (1), characterized in that the glass body (26) consists of at least two parts, that the alarm wire (25) runs between the at least two parts, and that shock absorbing materials (22) are placed between the inner wall of the bar (1) and the glass body (26).

Description

The invention relates to an alarm-triggerable lattice rod for a protective grille against burglary according to the preamble of the first claim.

For so-called area monitoring, grilles and doors are a conventional means of monitoring passages by means of a barrier through them. If, for example, there are lattice doors, alarm cables are drawn into the tubes, which are usually hollow, and routed to the alarm center via a flexible transition. When sawing through the bars, this alarm conductor is cut together with the tube; This intervention then triggers the alarm in the alarm center and indicates the location of the intrusion point. However, if the lattice bars or lattice tubes are bent apart with suitable aids instead of being sawn through in order to clear a passage in this way, this does not normally lead to the alarm wires tearing, since copper can be stretched more than steel on the one hand and the necessary tear lengths neither for steel nor for the other Copper can be brought about by this type of deformation.

Lattice doors, for example, whose hollow profiles are filled with compressed air, this is also a known procedure for additionally securing such surface surveillance, and are also largely insensitive to deflection. The pressurized lattice tubes connected to a pressure measuring device via flexible transitions suffer a pressure drop when damaged by sawing and welding, which triggers the alarm in the monitoring center and indicates the break-in point accordingly. When the pipes are bent apart, however, an alarm can only be triggered in the event of severe deformation, i.e. if, for example, intended breaking points begin to tear when the deformation has taken place. A major disadvantage of this type of protection is that a complex manufacturing process for the entire construction is required for the pneumatic tightness.

The well-known bending apart of lattice bars is therefore one of the most dangerous procedures for a possible break-in, be it through a lattice door or simply by securing the surface with a fixed lattice. The means required for such violence are relatively simple and in some cases. silent. These are, for example, jacks, lifting tools, clamping devices, etc., with the help of which the necessary forces can be exerted on the bars. The spreading out of somewhat long lattice bars <; n to the mass of a slip necessary for a person can be carried out in a matter of minutes without significant noise.

DE-C-265 216 (Meissner), from which the present invention is based, describes a lattice rod made of hollow profile for protective lattices against break-in. This lattice bar is primarily intended to protect against sawing, but does not confirm an electrical circuit. Rather, this lattice rod (column 2, lines 30-31) makes a strong noise when it is sawed through. Inside, the lattice bar has an iron bar, which is surrounded by a wire mesh. The entire interior is filled with molten glass.

Apart from the lack of an electrical circuit, this version is more difficult to manufacture because of the necessary melting and pouring in of glass and is also not designed in such a way that the alarm wire is sheared off when the wire rod is bent and cut.

GB-A-1 229 166 (Ariel) uses an electrical circuit, where a strong bending of the lattice bar causes the actuation of a circuit by two conductive tubes arranged one inside the other touching each other. There are a number of thin, insulated wires in the inner tube. If the two pipes, e.g. during a bending process, touch each other, or the wire e.g. is cut in a sawing process or torn during a bending process, a circuit is actuated for an alarm circuit. Furthermore, sawing through the tube 2 brings about a bridging of the air gap to the tube 1 and thus the actuation of the circuit. The design according to this patent specification (Ariel) with three conductors arranged one inside the other is relatively complicated and requires high accuracy, which causes a corresponding sensitivity during operation. This sensitivity can e.g. are reduced by the rings mentioned on page 2, lines 37-41, but this makes the structure even more complicated.

DE-A1-2 925 624 (Geiger) describes a safety grate in which the individual bars are hollow and filled with gas or air. The gratings are especially for power and nuclear power plants, e.g. provided in the inlet channel for the cooling water. This creates problems e.g. with the sealing and the conductivity of water. The design can be compared to ARIEL, but is simpler with the exception of the waterproofing. Another feature of this version is the pretensioning of the alarm wire by means of a spring

CH-A-148 303 describes various electrical or electromechanical alarm systems for protection against theft and burglary. It only marginally affects the present application.

The object of the invention is to create an alarm-triggerable 'grid rod for protective grids against burglary and theft, the grid rod being to be protected against bending and severing. In the event of damage, the grating rod is also intended to actuate a circuit for an alarm system.

The lattice bar should also be designed so that it can also be used against other influences behaves as insensitive to violence.

The object is achieved by the features specified in the characterizing part of the independent claim.

• Fig. 1 eine ülicherweise verwendete Gittertüre mit Zarge und Verankerungen.
• Fig. 2 im Beispiel eine ebensolche Gittertüre, die mit einfachsten Mitteln partiell zerstört wurde,
• Fig. 3 die Ansicht eines gemäss Fig. 1 an der Stelle A-A geschnittenen Gitterstabes gemäss Erfindung,
• Fig. 3a die elektrische Zusammenschaltung und den Verlauf von Alarmdrähten innerhalb eines Gitterstabes gemäss Erfindung und
• Fig. 3b ein Diagramm zur Darstellung der Zusammenhänge, die den in der Erfindung benützten Effekt bewirken.

The invention will now be explained in more detail with the aid of the drawings listed below. Show it:

• Fig. 1 is a commonly used lattice door with frame and anchors.
• 2 in the example a similar lattice door which was partially destroyed with the simplest means,
• 3 shows the view of a lattice bar cut according to FIG. 1 at position AA according to the invention,
• 3a shows the electrical interconnection and the course of alarm wires within a lattice bar according to the invention and
• Fig. 3b is a diagram showing the relationships that cause the effect used in the invention.

The lattice door shown in Fig. 1, of a type which has been most widely used in this type of concept, essentially consists of a door leaf frame 2 with fitted, for example vertical, lattice bars 1, a frame 4 and frame surrounding the door leaf in the closed state several, in this example 2, door hinges 3.

A security lock 10 with an opening handle is also arranged in the door leaf; in addition, for safety reasons, the relatively long grating bars 1 are connected to one another by cross members 5. Of course, the whole arrangement, in order to increase the degree of security again, can be arranged rotated by 90 °, namely shorter, horizontally extending bars and a few cross members connecting the bars in a vertical direction. The door frame 4 is firmly connected to the surroundings, for example a gallery, a wall, a corridor, etc., by walling in the numerous anchors 7 surrounding it. In addition to the hinges 3, the door leaves and door frames are in fixed engagement with one another through the displaceable locking bar ends 9, 9 '. All of these peg-shaped means causing the intervention are protected in such a way that a simple sawing through to avoid the intervention is not possible.

Interventions by sawing, bending, welding and other things are primarily exposed to the bars. If the lock and the interlocking elements are protected by armor against unauthorized access, this cannot be done with the bars for obvious reasons. These parts of a device preventing passage, such as the lattice door - this also applies to fixed lattices - are passively protected. The unauthorized intervention can take place, but this triggers an alarm.

Sawing through the bars will in any case result in an interruption of the alarm wires and thereby still trigger the desired alarm. The far more dangerous bending of lattice bars to the size of a slip which the lattice bar is intended to counteract according to the invention is shown in FIG. 2, for example. After sawing through the crossbeams 5, one of the bars 1 is bent out of the door plane by the action of a force K. If one of the neighboring lattice bars is bent in the other direction after being released from the crossbeams, a slippery slippage is normally already achieved. However, if only a slight deflection is possible without triggering an alarm, a sufficiently large slip cannot be formed at any point on the lattice door shown. The security requirement against burglary is guaranteed with this door. Incidentally, it turned out that the attachment of additional trusses is an additional, but not burglar-proof, protection. It is therefore clear to see that the deflection of the bars can only be very limited so that a grid can be considered burglar-proof.

A lattice bar according to the invention is constructed as follows: FIG. 3

An alarm laminated glass rod 20 is embedded over its entire length in a hollow lattice rod 1, which is sufficiently strong to withstand mechanical influences due to its wall thickness. The cross section of the lattice bar can have any profile, round, square, rectangular, etc. A silicone layer is provided as an embedding 22 between the tube wall 23, preferably a steel tube, and the alarm composite glass rod 20. Instead of silicone, other elastic material can also be used. such as neoprene rubber, etc. can be used. It is preferable to use a material that is rot-proof for a relatively long period of time, in particular does not become brittle in the cold, and in this state easily crumbles when shaken, and is easy to insert into the spaces between glass and metal. Last but not least, the embedding material should be largely chemically neutral.

The alarm composite glass rod embedded in the lattice consists of at least two glass bodies 26, a spacer 24 arranged between the glass bodies and an alarm wire 25 embedded therein. The spacer can easily consist of the adhesive layer which produces the glass composite, in which an approx. 0.06 mm thick alarm wire 25 runs. It is important to ensure that the hair-fine alarm wires are not pinched at any point, because a pinch point that deforms the wire more and more due to vibration pressures can cause a false alarm over time. The entire assembly is surrounded by a hermetic seal, a sealing layer, or only attached via the gap-like longitudinal opening. This termination serves as a corrosion barrier 21 because the alarm wires must be protected against any corrosion.

In a particular embodiment, the alarm laminated glass rod 20 is in one on one Side open lattice rod 1 introduced. An elastically deformable buffer is inserted into the inside of the grille on the closed side. The alarm composite glass rod is placed on this buffer as it were, ie the weight of the Atarm composite glass rod rests on this elastic base. The alarm wire runs twice between the vitreous bodies over a loop; both ends of the alarm wire lie on one side and thus form an incoming wire part 25 and a returning wire part 25 '(Fig. 3a).

The two ends can be connected to the main line 30, 30 'by soldering. This type of arrangement and wiring is shown in Fig. 3a. The two conductors 30, 30 'of the main line are routed in a known manner inside the hinge from the door leaf via the frame to the outside.

The lattice bar according to the invention is insensitive to vibrations, such as those that occur when a lattice door slams shut, as well as weather or climate-related effects of temperature. Bending to a limited extent (this dimension will be given below) is also possible without triggering the alarm due to the inherent elasticity of the glass. However, as soon as the glass rod breaks due to greater deformation, the force built up by the tension in the glass causes a relatively large spatial displacement to relieve the tension. As a result of this shift, the alarm wire is finally torn.

3b shows in a simplified manner the relationships which bring about the desired effect, that is to say the tearing of the alarm wires. The diagram shown corresponds essentially to a stress / strain diagram, but without specifying the relative strain. This is replaced by the absolute extension I. The elasticity range of glass corresponds to the length BLG and is indicated by the elasticity line EG. A straight line of elasticity EM for metal, which extends far along the length axis, is intended to indicate a certain energy store from the elastic deformation of the grating. At point B of the stress / strain curve of the glass, because of its amorphous structure without climbing, flowing and plastic deformation, the glass body is suddenly broken. In this case, a relatively large number of fractures occur, all of which are displaced relative to one another by relatively large lengths under the tension effect of the elastically deformed tubular metal. Although the plastic deformation on the trellis tube has already partially occurred, there is always an elastic component of the deformed metal trellis tube, which therefore contains energy. These forces are therefore used to exert a strong shear or shear effect on the alarm wire at the glass fragments caused by the break and which shift into mutual displacement. The large number of glass particles under pressure in the shear direction with their sharp cutting edges will cut the alarm wire twice through the glass body at some point. In Fig. 3b, the relatively large spatial displacement of the glass particles under the action of tension is caused by a rapidly decreasing, i.e. the stress-relieving and rapidly shifting curve. F denotes the dislocation area in which the shear effect on the alarm wires is to take place. The relatively thin wires are cut with little force by the glass fragments and an alarm is triggered.

The bending length BLG from the glass is achieved in the composition and with a rectangular cross-section, with a force in the grid area up to a deformation of up to 5 mm and with a force perpendicular to the grid surface up to a deformation of 20 mm. However, these are the permanent plastic deformations of the lattice rod after an alarm is triggered; the elastic action or the influence of the spring force can then no longer be measured as a dynamic variable. The deformations given relate to a lattice bar length as they are generally used in lattice doors according to FIG. 1 and after the crossbars have been removed, as shown in FIG. 2. It is no longer possible for a small person or even a child to climb through such gaps in a grating device secured according to the invention.

Claims (3)

1. Grate bar (1) capable of triggering an alarm, with a hollow metal section (2) with at least one alarm wire (25) for the operation of an alarm device, the alarm wire (25) being placed in a glass body (26), which practically fills the entire hollow space of the bar (1), characterized in that the glass body (26) consists of at least two parts, that the alarm wire (25) runs between the at least two parts, and that shock absorbing materials (22) are placed between the inner wall of the bar (1) and the glass body (26).

2. Grate bar according to claim 1, characterized in that the glass body (26) with the alarm wire (25) is inserted into the hollow space in the bar (1).

3. Grate bar according to claim 1 or 2, characterized in that the alarm wire (25), in case of destruction, operates the alarm device.

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