Hybrid stranded conductor

Abstract

A hybrid strand includes a core and outer wires arranged around the core, wherein at least a part of the outer wires is compressed, wherein the compressed outer wires include a flattened cross-sectional shape, the outer wires are composed of steel, and the core is a fiber core. A corresponding production method produces such a hybrid strand.

Claims

1. Hybrid strand comprising a core and outer wires arranged around said core, wherein at least a part of the outer wires is compressed, the compressed outer wires comprise a flattened cross-sectional shape, the outer wires are composed of steel and the core is a fiber core, wherein a first compressed outer wire is spaced apart from an adjacent compressed outer wire, and wherein a lateral flattened area of the first compressed outer wire faces a lateral flattened area of the adjacent compressed outer wire at a distance.

2. Hybrid strand according to claim 1, wherein the compressed outer wires comprise a trapezoidal or circular-segment-shaped cross-section.

3. Hybrid strand according to claim 1, wherein the distance between the facing flattened areas is constant at least in sections.

4. Rope comprising several hybrid strands according to claim 1.

5. Rope according to claim 4 in the form of an anti-twist rope.

6. Method for the production of a hybrid strand, wherein outer wires made of steel are wrapped and compressed around a fiber core, wherein the outer wires during compression contact each other in a lateral contact area, wherein after compression at least a part of the outer wires comprises a flattened cross-sectional shape in the contact area, wherein the outer wires support each other in a vault-like manner during the compression, and wherein the outer wires are pressed against the fiber core during compression prior to the vault formation and spring back to a corresponding extent after compression, so that the deformed outer wires of the compressed hybrid strand are spaced apart.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will be described in more detail on the basis of preferred embodiments, to which it is not limited, however, with reference being made to the enclosed drawings, in which:

(2) FIG. 1 schematically shows an axonometric view of a portion of a hybrid strand still prior to the compression of the outer wires;

(3) FIG. 2 shows an identical axonometric view of said hybrid strand after the compression of the wires of the outer layer;

(4) FIG. 2A shows a cross-sectional view of the hybrid strand wherein the distance between adjacent deformed outer wires is shown excessively large only for illustrative purposes;

(5) FIG. 3 shows a cross-section through a non-anti-twist hybrid rope with such hybrid strands; and

(6) FIG. 4 shows an anti-twist hybrid rope using such hybrid strands.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIG. 1 schematically shows a part of a hybrid strand 1 in a diagrammatic view. This hybrid strand 1 comprises a fibre core 2 as well as steel wires 3 wrapped around this fibre core 2, wherein in the example shown in FIG. 1 only one layer of wires (outer wires) 3 is shown. However, it would also be conceivable to provide here (just like in the subsequent examples) two or more layers of wires, with an outer layer of wires 3 that are cold-formed in the subsequent compression. Such cold forming may be gathered from the view shown in FIG. 2, where it may be seen that the wires 3 around the fibre core 2, after compression, now abut to each other with their sides in a flat manner and have an approximately trapezoidal cross-section. On the whole, the hybrid rope or the hybrid strand 1 now has a smaller cross-section as compared to FIG. 1, with a compression of the (outer) wire layer 4 comprising the wires 3.

(8) FIG. 3 shows a cross-section through a hybrid rope 5 which is not torsion-free in this embodiment and in which compressed hybrid strands 1 according to FIG. 2 have been used. Specifically, a core hybrid strand 6 is provided, around which six hybrid strands of an inner strand layer 7 are arranged. Finally, an outer layer 8 is provided with eight hybrid strands 1 (according to FIG. 1), wherein a plastic intermediate layer 9 supports the outer hybrid strands 1 of this outer layer 8, as is known as such.

(9) For the purpose of comparison, FIG. 4 shows a cross-section through a torsion-free hybrid rope 10, wherein comparable hybrid strands 1 (cf. FIG. 2) are used, on the one hand, for the core 11 of the rope 10 and, on the other hand, for the construction of a total of three strand layers 12, 13 and 14. The hybrid strands (1 in FIG. 2) also have different diameters to obtain a compact construction.

(10) The hybrid rope 10 according to FIG. 4 is torsion-free, with no plastic intermediate layer or support body being used, such as is shown in the case of the rope 5 according to FIG. 3. The cross-sections according to FIG. 3 and FIG. 4 are examples of possible rope constructions, wherein of course different types of other rope constructions are possible.

(11) As may be seen in particular from FIG. 2, more compact cross-sections can be obtained by the compression of the hybrid strand 1 or the cold forming of the outer wires 3, whereby the entire cross-section of the hybrid strand 1 is reduced, and whereby the cross-sections of the wires 3 change from a round cross-sectional shape to an approximately trapezoidal or circular-segment shape (wires 3). The cavities between the wires 3 or 3 are reduced by the compression process, whereby the relative metallic cross-section and thus also the breaking force of the hybrid strand 1 is increased essentially. On the whole, ropes 5 and 10, respectively are made possible in this manner, which may have a weight that is about 30% lower in the case of a breaking force identical to that of a conventional steel rope or vice versa may have an essentially higher breaking force in the case of the same weight.

(12) The following table 1 shows a comparison of values for a conventional compressed steel rope and a compressed hybrid rope, for example according to FIG. 3.

(13) TABLE-US-00001 TABLE 1 steel rope Compressed hybrid rope Rope nominal Weight per Specific Weight per Specific diameter meter strength meter strength 24 mm 2.75 kg/m 188 kN/kg 1.95 kg/m 265 kN/kg

(14) The compressed hybrid rope has a specific strength that is 40% higher compared to a compressed rope that is entirely composed of steel.

(15) A comparison of a compressed and a non-compressed hybrid rope (with identical breaking force) will resultaccording to table 2in the following nominal diameter of the rope.

(16) TABLE-US-00002 TABLE 2 Hybrid rope compressed Hybrid rope uncompressed Nominal of rope Nominal of rope 24 mm 25.25 mm

(17) It is added for the sake of completeness that specific breaking force means the ratio between the general breaking force and the weight per meter of a rope.

(18) As stated previously, in the present method, the fiber core will yield only to such an extent until the wires, in particular wires of an outer layer in the case of several layers of wires, completely contact each other. It is particularly favorable when these outer wires support each other during the compression in a vault-like manner. Due to this mutual support of the wires as a result of the vault formation, the entire radial pressure will act upon the outer wire layer upon compression, and the desired plastic cold forming of the outer wires may take place. If prior to the vault formation the wires have been pressed a bit against the fibre core during compression, they may spring back to some extent after compression, so that the deformed wires of the compressed hybrid strand may slightly be spaced apart by a distance D. See FIG. 2A.