AU2013206251B2 - Cable, combined cable made of plastic fibers and steel wire strands, and combined strands made of plastic fibers and steel wires - Google Patents

Abstract

- 12 Abstract: Cable, combined cable of synthetic fibers and steel wire strands and combined strand of synthetic fibers and steel wires A combined cable comprising a core cable of high strength synthetic fibers, which take the form of a twisted bundle of monofilaments or a plurality of twisted bundles of monofilaments, and comprising an outer layer of steel wire strands, is characterized in that the bundle or bundles of monofilaments is or are stretched, with a reduction in diameter, and held in this state by a sheathing, in particular a braided sheathing. The extension under strain of the core cable under load is thereby reduced, so that the load distribution between the cross section of steel and the cross section of synthetic material of the cable improves. In order, in the same sense, conversely to make the strain behavior of the layer of strands approximate that of the core cable, the cable has an intermediate layer of an elastic synthetic material into which the steel wire strands are pressed while spaced apart from one another in such a way that the outer layer extends under load, and contracts radially. A strand can be analogously constructed. (Figure 3) 4384443_1 (GHMatters) P82773.AU.1

Description

Description: Cable, combined cable of synthetic fibers and steel 5 wire strands and combined strand of synthetic fibers and steel wires The invention relates to a cable of high-strength synthetic fibers, which take the form of a bundle of 10 monofilaments, in particular a twisted bundle of monofilaments, or a plurality of twisted bundles of monofilaments, which is or are enclosed by a sheathing. In particular, the invention relates to a combined 15 cable comprising a core cable of high-strength synthetic fibers and an outer layer of steel wire strands. Furthermore, the invention relates to a combined strand 20 comprising a core of high-strength synthetic fibers and an outer layer of steel wires. Cables of the aforementioned type, comprising a braiding protecting the synthetic fibers, are known 25 from use, in particular for sports purposes. A combined cable of the aforementioned type is known from US 4,887,422, comprising a sheathing of the core cable, which is extruded or wound on. 30 A combined strand of the aforementioned type is not state of the art. An advantage of the high-strength synthetic fibers, 35 both in the cables on their own and in the combined cables and strands, is their low weight and volume in comparison with their strength. 7020517_1 (GHMatters) P82773.AU.1 DENISET - 2 This advantage comes into effect in particular in the case of cables of great length for suspended use, such as hauling or hoisting cables in mining or deep-sea 5 cables. This is so because, during such use, the weight of an entirely wire cable already takes up a large part of its load-bearing capacity itself; the payload is correspondingly limited. 10 An advantage of the combined cable over the entirely synthetic cable is its much lower sensitivity to disturbing mechanical influences. Furthermore, the replacement state of wear of a wire cable can be seen in good time from the visible wire breakages. 15 While the breaking strength of the high-strength synthetic fibers, for example aramid copolymer 3470 N/mm 2 , aramid HM (high modulus) 2850 N/mm 2 , aramid HS (high strength) 3350 N/mm 2 , aramid SMS (standard 20 modulus) 2850 N/mm2 , HMPE 3400 N/mm 2 and liquid-crystal polyester 2800 N/mm2 , exceeds that of steel wire, for example 1770 N/mm2 , and so in itself can contribute decisively to the load-bearing capacity of a combined cable, the extensions under the strain differ however 25 to such a degree that there is scarcely a cable construction among the known cable constructions in which the core cable of synthetic material can take a significant part in bearing the load. The moduli of elasticity of the fiber materials above are 73, 120, 30 60, 60, 85 and 65 GPa, respectively, as compared with an average of 200 GPa for steel wires. In addition to this in particular is the fact that the actual load bearing of the synthetic fibers is delayed, because, under any load, bundles of monofilaments first have to 35 "settle", i.e. have to find a final spatial order, forming a stable bundle cross section. 7020517_1 (GHMatters) P82773.AU.1 DENISET - 3 An embodiment of the invention may increase the effective load-bearing capacity of a core cable of synthetic fibers in a combined cable and, in relation to the synthetic cable itself, of increasing the load 5 bearing capacity in another sense. According to a first aspect of the invention, there is provided a combined cable having a core cable with high-strength synthetic fibers and an outer layer of 10 steel wire strands, wherein the core cable is enclosed by a sheathing which is provided in addition to the outer layer, wherein the core cable is in the form of a single twisted bundle of monofilaments or a plurality of twisted bundles of monofilaments, and the bundle or 15 bundles of monofilaments is or are stretched, with a reduction in diameter, and held in this state by the sheathing. In an embodiment, the bundle or bundles of 20 monofilaments is or are stretched such that the synthetic fibres have found their final spatial order, forming a stable bundle cross section, and a cross section of the bundle of monofilaments that is assumed in the stretched state is held by the sheathing. 25 In an embodiment, the combined cable has an intermediate layer of an elastic synthetic material into which the steel wire strands are pressed while spaced apart from one another, such that the outer 30 layer extends under load, and contracts radially. In an embodiment, the intermediate layer is extruded on. 35 In an embodiment, the intermediate layer is formed from a foam plastic, a polyurethane, a polyester, a polyolefin or a polyamide. 7020517_1 (GHMatters) P82773.AU.1 DENISET In an embodimement, the combined cable can be used for suspended use over a difference in height, wherein the length of lay over the length of the cable is changed, 5 such that the load-specific torque of the wire cable decreases upward. Acting like a corset, the sheathing fixes the cross section of the bundle of monofilaments assumed under 10 the stretching mentioned. This at least may largely eliminate the process of "settling" before and at the beginning of bearing loads, it is completed once and for all. The normal load bearing under elastic strain of the synthetic fibers in accordance with Hooke's law 15 can begin immediately. In a combined cable, the strain behavior of the core cable consequently can approximate that of the steel wire layer. 20 With the same load-bearing capacity, a cable on its own can have, for example, a diameter reduced by 10%, i.e. a greater load-bearing capacity in relation to the diameter. 25 As a variant and a particularly advantageous development of an embodiment of the invention, it is proposed to make the strain behavior of the steel wire layer of a combined cable approximate that of the core 30 cable of synthetic fibers by subjecting the steel wire layer to the reverse version of the measure of an embodiment of the invention affecting the core cable: it can be able to extend under load and take on a cross section that changes to make this possible. 35 The actual measure of an embodiment of the invention in this version comprises that the cable has an 7020517_1 (GHMatters) P82773.AU.1 DENISET - 5 intermediate layer of an elastic synthetic material into which the wire strands are pressed while spaced apart from one another in such a way that the outer layer extends under load, and contracts radially. 5 The elastic compliance of the intermediate layer and the spacing of the wire strands from one another can allow the helical lines described by the strands to draw out in length while increasing their pitch, with a 10 reduction in their diameter and accordingly the spacing of the strands. As a result of the elasticity of the synthetic material, the process can be reversible when the load 15 is relieved, in other words the desired effect can be obtained with every new load-bearing instance. The advantages of the first version and the reverse version of embodiments of the invention can 20 respectively be used on their own, but with great success together. By analogy with the combined cable, a combined strand can be created. In place of the core wire of the 25 strand, there can then be a cable that is formed in a way similar to the core cable of the strand but correspondingly thin. (The designation "cable" comprises strands of bundles of monofilaments irrespective of the construction.) 30 A second aspect of the invention provides a combined strand having a core strand with high-strength synthetic fibers and an outer layer of steel wires, wherein the core strand is enclosed by a sheathing 35 which is provided in addition to the outer layer, wherein the core strand is in the form of a single twisted bundle of monofilaments or a plurality of 7020517_1 (GHMatters) P82773.AU.1 DENISET - 6 twisted bundles of monofilaments, and the bundle or bundles of monofilaments is or are stretched, with a reduction in diameter, and held in this state by the sheathing. 5 In an embodiment, the bundle or bundles of monofilaments is or are stretched such that the synthetic fibres have found their final spatial order, forming a stable bundle cross section, and a cross 10 section of the bundle of monofilaments that is assumed in the stretched state is held by the sheathing. In an embodiment, the combined strand has an intermediate layer of elastic synthetic material into 15 which the steel wires are pressed while spaced apart from one another, such that the outer layer extends under load, and contracts radially. In an embodiment, the intermediate layer is extruded 20 on. In an embodiment, the intermediate layer is formed from a foam plastic, a polyurethane, a polyester, a polyolefin or a polyamide. 25 A third aspect of the invention provides a combined cable of the first aspect, wherein the outer strand of the combined cable is in the form of a combined strand according to the second aspect. 30 Particularly suitable as the sheathing mentioned can be a braiding. In a braiding machine, the bundles of monofilaments can be simply stretched by being driven at the output of the machine, for example by a pair of 35 rollers, to make them continue in their advancement, and restrained at the input of the machine, for example by means of a braked pair of rollers, and the braiding 7020517_1 (GHMatters) P82773.AU.1 DENISET can be performed with a prestress. However, it can be likewise conceivable for them to be wound around. If appropriate, the stretching can also be brought about by the reduction in cross section. 5 The intermediate layer mentioned is generally extruded on, as commonly occurs in the prior art, if appropriate onto the sheathing mentioned. It can be be difficult to combine the sheathing and the intermediate layer 10 since the two of them serve different purposes, and accordingly must have different properties. The sheathing should be as non-compliant as possible, the intermediate layer should be soft. Foam plastic can also come into consideration for the intermediate 15 layer. Suitable materials for the sheathing can be, for example, polyester fibers; suitable materials for the intermediate layer are polyurethanes, polyesters, 20 polyolefins and polyamides. To be mentioned finally as a particularly advantageous use of a core cable according to an embodiment of the invention is a combined cable for suspended use over a 25 great difference in height, in particular with a lower end rotationally fixed, in particular a hoisting cage cable, deep-sea cable or cable car cable, which is characterized by changing of the length of lay over the length of the cable, in such a way that the load 30 specific torque of the wire cable decreases upward. A wire cable of this construction is known from DE 36 32 298, which is hereby incorporated in the disclosure content of the present application. 35 With the changing of the length of lay mentioned, twists within the cable structure that are caused by 7020517_1 (GHMatters) P82773.AU.1 DENISET - 8 the weight of the cable can be avoided, in particular further twistings of the layer of strands in the lower region of the cable, which would tend to shorten the cable there, and may consequently act against the load 5 bearing of the core cable. Embodiments of the invention are to be explained in more detail below on the basis of examples with reference to the non-limiting Figures. 10 Figure 1 shows a load-strain diagram for various materials, Figure 2 shows a load-strain diagram of a normally 15 stranded steel wire layer and a steel wire layer stranded on an elastic, soft intermediate layer according to an embodiment of the invention, 20 Figure 3 shows a load-strain diagram of a core cable of synthetic fibers for a combined steel wire/synthetic-fiber cable with and without sheathing according to an embodiment of the invention, 25 Figure 4 shows a load-strain diagram of the core cable and the wire cable layer of a combined cable as shown in Figure 5, 30 Figure 5 shows a cross section of a combined cable with a core cable of synthetic fibers and an outer layer of steel wire strands and Figure 6 shows a cross section of a cable 35 corresponding to Figure 5 with different strands. 7020517_1 (GHMatters) P82773.AU.1 DENISET - 9 In Figure 1, the materials concerned are respectively indicated right alongside the curves. The steel wire follows Hooke's law only in the lower load range, since it is produced by drawing and, as a consequence, does 5 not have the normal structure. Use normally only takes place approximately in the lower half of the curves. Figure 2 gives the curve profile of the steel wire in Figure 1 with the normally twisted layer of strands 10 (upper curve). The lower curve shows the effect of the embedding of the strands in a soft intermediate layer according to an embodiment of the invention: up to an extension under strain of approximately 0.6%, the curve runs approximately horizontally. Here, the extension 15 under strain comprises that the helical lines of the wound strands are drawn out in length while the diameter of the helical lines is reduced, virtually without bearing any load. The load bearing only begins subsequently. 20 As can be seen from Figure 3, the aforementioned process of settling (lower curve), which is pronounced up to an extension under strain of 0.5% and then subsides, but is still noticeable up to an extension 25 under strain of approximately 1%, can be largely eliminated by the sheathing according to an embodiment of the invention (upper curve). By contrast with the lower curve, the upper curve rises from the beginning, even though the final proportionate rise in accordance 30 with Hooke's law only commences approximately between an extension under strain of 0.5 and an extension under strain of 1%. The use of both measures of an embodiment of the 35 invention in a combined cable, as shown in Figure 5, can be seen from Figure 4. Here, the lower curve of 7020517_1 (GHMatters) P82773.AU.1 DENISET - 10 Figure 2 and the upper curve of Figure 3 lie close together. In the cross section of the cable construction of 5 Figure 5, the measures of an embodiment of the invention can only be seen to the extent that it shows a sheathing 2 of a core cable 1 and also an intermediate layer 3, into which an outer layer of steel wire strands 4 is pressed. 10 Within the sheathing 2, the core cable 1 comprises a bundle of monofilaments or a number of bundles of monofilaments, which are in each case only twisted to the extent that they stay together and can be handled. The sheathing 2 comprises a braiding of preferably 15 polyester filaments. It sits under prestress on the bundle or bundles of monofilaments, which after an extension under strain keeps them together in the settled state. The intermediate layer 3 is extruded over the sheathing 20 2 of the core cable 1 in a way known per se. It consists of a soft-elastic synthetic material, for example polyethylene or polypropylene. The steel wire strands 4 are twisted over that and have 25 been pressed, for example, into the still warm intermediate layer 3 in such a way that, spaced apart from one another, they each have their own bed. The intermediate layer 3 is so elastic-soft and the steel wire strands 4 have such a spacing from one 30 another (somewhat greater than in the drawing) that the layer of steel wire strands 4 initially lengthens somewhat under load, and its diameter is reduced. The strain curves (Figure 4) of the layer of strands and of the core cable are made to approach one another as a 35 result, i.e. the load bearing is shared approximately in accordance with the cross sections of the layer of strands and the core cable. 7020517_1 (GHMatters) P82773.AU.1 DENISET - 11 The cable according to Figure 6 has the same basic construction as that according to Figure 5, comprising a core cable 1, a braided sheathing 2, an extruded-on 5 intermediate layer 3 and an outer layer of strands, designated here by 5. The strands 5 have a construction analogous to the cable, once again with a, thinner, core cable 6 of high-strength synthetic fibers, a braided sheathing 7, an extruded-on 10 intermediate layer 8 of a soft-elastic synthetic material and an outer layer of steel wires 9. On account of its greater cross section of synthetic material, the cable has the advantage of still lower weight, but at the same time, with the steel wires in 15 the outer layer, is likewise robust. The intermediate layer 3 could also be omitted in the case of this cable, since the outer strands 5 already themselves have increased extensibility. 20 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in 25 Australia or any other country. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary 30 implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the 35 invention. 7020517_1 (GHMatters) P82773.AU.1 DENISET

Claims (14)

1. Combined cable having a core cable with high strength synthetic fibers and an outer layer of steel wire strands, wherein the core cable is enclosed by a sheathing which is provided in addition to the outer layer, wherein the core cable is in the form of a single twisted bundle of monofilaments or a plurality of twisted bundles of monofilaments, and the bundle or bundles of monofilaments is or are stretched, with a reduction in diameter, and held in this state by the sheathing.

2. Combined cable as claimed in Claim 1, wherein the bundle or bundles of monofilaments is or are stretched such that the synthetic fibres have found their final spatial order, forming a stable bundle cross section, and a cross section of the bundle of monofilaments that is assumed in the stretched state is held by the sheathing.

3. Combined cable as claimed in Claim 1 or 2, wherein the combined cable has an intermediate layer of an elastic synthetic material into which the steel wire strands are pressed while spaced apart from one another, such that the outer layer extends under load, and contracts radially.

4. Combined cable according to Claim 3, wherein the intermediate layer is extruded on.

5. Combined cable according to Claim 3 or 4, wherein the intermediate layer is formed from a foam plastic, a polyurethane, a polyester, a polyolefin or a polyamide. 7020517_1 (GHMatters) P82773.AU.1 DENISET - 13

6. Combined cable according to any one of Claims 1 to 5 for suspended use over a difference in height, wherein the length of lay over the length of the cable is changed, such that the load-specific torque of the wire cable decreases upward.

7. Combined cable according to Claim 6, wherein the combined cable is a cable car cable.

8. Combined cable according to Claim 6, when used as a hoisting cage cable, deep-sea cable or cable car cable.

9 Combined strand having a core strand with high strength synthetic fibers and an outer layer of steel wires, wherein the core strand is enclosed by a sheathing which is provided in addition to the outer layer, wherein the core strand is in the form of a single twisted bundle of monofilaments or a plurality of twisted bundles of monofilaments, and the bundle or bundles of monofilaments is or are stretched, with a reduction in diameter, and held in this state by the sheathing.

10. Combined strand according to Claim 9, wherein the bundle or bundles of monofilaments is or are stretched such that the synthetic fibres have found their final spatial order, forming a stable bundle cross section, and a cross section of the bundle of monofilaments that is assumed in the stretched state is held by the sheathing.

11. Combined strand according to Claim 3 or 10, wherein the combined strand has an intermediate layer of elastic synthetic material into which the steel wires are pressed while spaced apart from one 7020517_1 (GHMatters) P82773.AU.1 DENISET - 14 another, such that the outer layer extends under load, and contracts radially.

12. The combined strand as claimed in Claim 11, wherein the intermediate layer is extruded on.

13. Combined strand according to Claim 11 or 12, wherein the intermediate layer is formed from a foam plastic, a polyurethane, a polyester, a polyolefin or a polyamide.

14. Combined cable according to any one of Claims 1 to 8, wherein the outer strand of the combined cable is in the form of a combined strand according to any one of Claims 9 to 13. 7020517_1 (GHMatters) P82773.AU.1 DENISET