The present invention relates to a high-security cable, which is manufactured of a mixture of plastic yarns or of plastic yarns and metal wires.
High-security cables are used in many applications. Today, in particular, high-security cables are known, which are used as safety arrester cables, in particular for connecting a wheel of a racing car to its chassis. Such a safety arrester cable is known from WO 03/048602. The mentioned cable consists of a mixed yarn of threads with relatively rigid plastic filaments with an extension until breakage of 2 to 5%, and of relatively elastic plastic filaments with an extension to breakage of 12 to 25%. Here, the various plastic filaments are twisted into yarn strands, wherein the yarn strands are twisted in a balanced manner, whilst the cable manufactured of these yarn strands is twisted in an unbalanced manner. Such a cable not only has large tensile strength, but also an increased extension, by which means one may achieve an improved energy uptake. Given a full loading, the total energy is not transmitted directly to the anchoring, which often represents the critical location in the complete system, thanks to the accordingly increased energy uptake by the cable itself.
The known safety arrester cable, which used in “Formula 1” racing, may only have a relatively short extension path for reasons of safety, in order to prevent the broken-off wheel which now hangs on the arrester cable from being thrown onto the cockpit or the head of the driver. However, a longer extension path would not only be acceptable, but, as the case may be, even desirable with other racing vehicles, or in other applications. The applicant has carried out further research and development in this direction, and has particularly sought after solutions which practically permit the creation of a customer-specific adaptation to the specifications.
Considering the so-called work-to-break-energy curve of any material, then such a curve in principle has the shape of an acute triangle in a coordinate system, with which the force is plotted on the abscissa and the elasticity E on the ordinate. The tensile strength of the material is reflected in the height of the triangle, and the elasticity of the material is represented by the inclination of the hypotenuse of the right-angled triangle. If, then, different materials are processed into a cable, then usually the material-specific peaks are clearly recognisable in the complete enveloping curve. This leads to extremely unfavourable tear behaviour, depending on the load.
It is therefore the object of the present invention to provide a high-security cable which, on account of its special manufacture, is capable of achieving a smoothing of the work-to-break-energy curve, by which means, as a whole, the energy which may be absorbed until breakage is to be increased. This object is achieved by a high-security cable with the features claimed herein. The invention relates also to the use of such a high-security cable for different applications, which until now have not been considered for cable of this type. In particular, the expanded application also results due to the fact that the cables may be manufactured of a combination of filaments of one or more plastics, as well as of wires of one or more metals or metal alloys.