MXPA99001979A - Protective network that includes connected crossed cables, for example networks for snow or for earth - Google Patents

Abstract

The protective network comprises cables (11, 12) that intersect in pairs and that define points of intersection (10) in which the pairs of cables (11, 12) are fixed by means of connection (13, 14, 15, 16 ) comprising two first wires (13, 15), each of which has windings around the respective cable (11, 12), on each side of an intersection point and extending through the other cable (12, 11). ) in order to restrict it at the point of intersection. The connecting means further comprises at least two additional wires 14,16) wound or wound around the respective cables and inserted between the windings of the first two wires (13, 15), so that they form groups of turns located in the vicinity of each intersection point

Description

PROTECTIVE NETWORK THAT INCLUDES CONNECTED CROSSED CABLES, FOR EXAMPLE, NETWORKS FOR SNOW OR FOR LAND FIELD OF THE INVENTION The present invention relates to the field of protective nets, for example, snow or terrain nets. Merely by way of example, nets of this type can be used either alone as notched nets placed and fixed to the nets. ground or as part of protective barriers.

BACKGROUND OF THE INVENTION In mountainous regions, protective barriers are widely used to protect and protect facilities or infrastructures against possible landslides, rockfalls or avalanches. These protective barriers are generally constituted by metallic net structures that are sufficiently flexible to absorb the energy of bodies such as rocks, earth, avalanches or the like, which hit and push them. The nets, which are supported by poles fixed firmly in the ground or in the rock, are generally formed by crossed steel wires or cables, preferably at right angles. At the points of intersection, the cables are clamped by P1168 / 99MX connection devices of various types, of which the most common comprises a pair of opposite shaped plates between which the cables are attached. The connection devices of the above-mentioned known type have the disadvantage that they significantly increase the cost of the metal net and hence the cost of the barrier structure, due both to the intrinsic cost of the materials and to the manufacturing process. of the plates and, because in most cases, the cables have to be secured or secured manually at the points of intersection. Because protective barriers can be used to protect such large geographical areas that the barrier network often has to cover considerable distances, it can be understood that the problem of reducing the cost of the network is of paramount importance in the field. European Patent No. 0428848 describes a system for producing a barrier network constituted by crossed metal cables. At each intersection, two wires are joined in the form of a cross by two wires each having its ends wound or wound on a respective cable on opposite sides of the intersection point. This system is simple and economical and can also be at least partially automated.

P11S8 / 99MX However, the tests carried out by the applicant have shown that the known system of the aforementioned type is effective only when small charges are expected over the barrier network. In fact, the joint or junction between two crossed cables formed in accordance with the teachings of the aforementioned patent, was subjected to tension tests in a direction perpendicular to the plane of the network and to sliding tests performed by exerting a fraction on one of the Two crossed cables in the plane of the network. The results of the tests showed, first of all, a very high variability in the strength of the joint, probably due to the difficulty to achieve a uniform and balanced tightening of the windings of the wires in the cables. As a consequence of the wide variability of the results, it is impossible to guarantee that the resistance of the protective network as a whole, which comprises a very large number of these connections, is greater than the lowest of the values obtained experimentally. A second experimental result, not very encouraging, that emerged from the tests carried out, consisted of the deficient resistance of the union formed by the two wires, which, although comparable with the average of the known bull systems, is very far from the resistance of the best ones ( and more expensive) P11S8 / 99MX systems comprising clamping plates. The rupture of the union made experimentally always occurred through the flow of the wires, especially after the loosening of the joint was observed with the consequent separation of the cables at the intersection. The use of larger diameter wires did not solve the problem, because the greater curvature to which the wires had to be subjected during the winding around the cables made it difficult to achieve optimum tightening and also caused the hardening by attitude or by worked of metal, so that it became excessively fragile.

SUMMARY OF THE INVENTION The object of the present invention is to overcome the problems of the prior art and to provide a protective network that is simple, economical and very strong. A further objective of the invention is to provide a system for joining crossed cables that is reliable over time and that shows resistance values within a range of limited variability. In order to achieve the aforementioned objects, the subject of the invention are protective networks comprising cables that are crossed in pairs and that define points of intersection and, further comprising, a means of connection for fixing the pairs of cables in the intersection points, the middle P1168 / 99MX comprises two first wires, each of which has windings around the respective cable on each side of the intersection point and extend through the other cable in order to constrain it at the point of intersection, characterized in that the Connection means comprises at least two additional wires having windings around the respective cables, these windings are inserted between the windings of the first two wires to form groups of turns or turns located in the vicinity of the intersection point. In short, at least four wires, coupled in pairs, are provided in the region of each cable intersection, each pair of wires will be wound on one of the two cables, on opposite sides of the intersection point and extend through the cable. another cable in order to hold it. A further subject of the invention is a protective barrier comprising a plurality of posts supporting a protective net structure of the type indicated above. The invention also relates to a method for producing protective networks as defined above. The connection system of the present invention has achieved truly surprising results. In comparison with the known solution comprising only two wires, the resistance P1168 / 99MX of the joint is greatly increased to such a degree that, in the tensile tests performed on the joint of the present invention, the breaking load of the steel wires was reached before the joining wires showed signs of creep. In addition, the use of the two pairs of wires allowed their diameter to be reduced, which simplified the joining operations and considerably reduced the work hardening or attitude of the metal that was bent to form the windings. The range of variability of the bond strength was found to be very limited, thus providing good repeatability of the joint strength results obtained by the system of the present intention, without wishing thereby to provide the full explanation of the phenomena found, it is considered that the surprisingly better results of the present invention can be attributed to an effect that could not be predicted by an analysis of the solutions of the prior art, that is, by the additional friction that is created between the windings of the pair of coupled wires that are tightened against each other at the moment when the joint is subjected to a load. This mutual friction is added to the predictable friction of the wires in the steel cable to improve the overall strength of the joint, which are indicated in P1168 / 99 X the experimental results as well as the low variability of the resistance values and also the reduced separation of the two cables in the stress tests, the significant increase in the resistance of the slip connection in the plane of the The network is also of particular interest and is probably also due to the effect of the first of the strands of the cable pair against each other under a load.

BRIEF DESCRIPTION OF THE DRAWINGS Additional features and advantages will be apparent from the following detailed description of a preferred embodiment, provided only by way of non-limiting example, with reference to the accompanying drawings, in which: Figure 1 is a view in perspective of a union of two crossed metal cables, formed in accordance with the principle of the present invention; Figure 2 is a plan view of the joint taken on the arrow II of Figure 1; Figure 3 is a plan view similar to that of Figure 2 of a first variant of the joint; and Figure 4 is a plan view of another variant of the joint.

P1168 / 99 X DETAILED DESCRIPTION OF THE PREFERRED MODE OF THE INVENTION Next, with reference to Figures 1 and 2, the protective net - used alone as a notched net or as part of a barrier structure unit - comprises wires or cables crossed, preferably, but not necessarily, made of steel. In a region of generic intersection 10, a first cable 11 is crossed and supports a second cable 12. A pair of coupled wires 13 and 14, preferably metallic wires, is pressed transversely on the first cable 11, the ends 13a, 13b, 14a and 14b of the wires will be repeatedly wound or wound around the second cable 12 to form a group of turns on each side of the first cable 11. Correspondingly, a second pair of coupled wires 15 and 16 is pressed transversally under the second cable 12, the ends 15a, 15b, 16a and 16b of the wires will be repeatedly wound around the first cable 11 to form a group of turns on each side of the second cable 12. Preferably, the first pair of wires 13 and 14 extends obliquely on the first cable 11 and, similarly, the second pair of wires 15, 16 extends obliquely under the second cable, as shown in the drawings, so that the two wing pairs Mbres are arranged one with respect to the other in the form of a cross. Figure 3 shows a P1168 / 99MX alternative mode in which the wires 13, 14, 15 and 16 extend transversely with respect to the cables 11 and 12. One embodiment of the joint shown in the drawings, on which the tests were carried out but which did not thus, it should be understood as limiting the application of the present invention, it comprises steel cables with a diameter of 8 mm joined by two pairs of galvanized steel wires of equal diameter, preferably between 2 and 3 mm. Each end 13a, 13b, 14a, 14b, 15a, 15b, 16a and 16b of the wires is wound in five turns around the respective portion of the cable 11 and 12. Therefore, in total ten turns or turns of wire are arranged side by side in each of the four portions of wires 11 and 12, located on opposite sides of the joint. Naturally, many variations, of which all fall within the scope of the present invention, can be applied to the above-described embodiment. For example, as shown in Figure 4, the fastening or securing of the cables 11 and 12 at the point of intersection 10 is achieved by means of six wires 13, 14, 15, 16, 17 and 18 grouped in trios. In the particular embodiment shown in the drawing, each wire is wound, in four turns on each portion of cable 11 and 12. In this embodiment, the P1168 / 99MX greater practical difficulties for the formation of the windings of the wires on the cables, caused by the need to maintain in constant form the three wires parallel to each other during the winding, are compensated by the fact that wires can be used for less diameter. The wires 13, 14, 15 and 16 can be wound on the cables 11 and 12 manually or, preferably, automatically or semiautomatically by means of strains or machines specifically arranged for this operation. During the operation of the protective net, two rows of steel cables are provided, crossed, preferably at right angles. The cables of the same row are parallel and separate and are connected to the cables of the other row at the points of intersection according to the principle of the invention. In this way it is possible to produce a flexible network structure with generally quadrilateral and, preferably rhombic or square meshes that have an optimal ability to absorb the energy of bodies, such as, for example, stones, earth, avalanches or the like, which can hit her or push her The energy absorbed by the flexible network is discharged towards the support posts that are firmly fixed or fixed to the ground or to the rock in accordance with the techniques known in the field of forming safety barriers.

P1168 / 99MX Naturally, the principle of the invention remains the same, the forms of the embodiment and the details of construction can be varied widely with respect to those described and illustrated without deviating from the scope of the present invention.

P11S8 / 99MX

Claims (4)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A protective network comprising cables that are crossed in pairs and that define points of intersecting and also comprising connection means for ing the pairs of cables together at the points of intersection, the connection means comprises two first wires, each of which have windings around the respective cable on each side of an intersection point and they extend through the other cable in order to restrict it at the point of intersection, characterized in that the connection means comprises at least two additional wires which have windings around the respective cables, these windings are inserted between the windings of the first wires to form groups of turns or turns located in the vicinity of the point of intersection.
2. 2. The protective net according to claim 1, characterized in that the wires have round and uniform cross-sections of equal diameter.
3. 3. a protective barrier comprising a plurality of posts fixed or firmly secured to the ground, characterized in that the posts support a P1168 / 99 X protective network structure according to claims 1 or 2, the network structure is flexible in order to absorb the energy of the bodies that collapse.
4. 4. A method for producing a protective network, characterized in that it comprises the following steps: providing a plurality of cables in a cross arrangement, in such a way that the cables are crossed in pairs and define points of intersection; - providing connection means comprising wires to keep the pairs of cables fixed at the points of intersection; winding two or more wires around each wire on each side of an intersection point, the central portions of the two or more wires extend through the other wire in order to restrict it at the point of intersection, the two or more wires they are kept side by side during the winding on the cables. P1168 / 99MX