HIGH-STRENGTH FIBER ROPE FOR LIFTING EQUIPMENT SUCH AS CRANES

Description

[0001] The present invention relates to a high-strength fiber rope for lifting equipment such as cranes, comprising a rope core comprising high-strength plastic fibers and a sheath surrounding the rope core that optically indicates wear according to the preamble of claim 1.

[0002] For some time now, efforts have been underway in lifting technology, and especially in cranes, to replace the usual heavy steel cables with high-strength fiber ropes. These ropes are made of high-strength synthetic fibers such as aramid fibers (HMPA), aramid / carbon fiber blends, high-modulus polyethylene fibers (HMPE), or poly(p-phenylene-2,6-benzobisoxazole) fibers (PBO), or at least contain such fibers. The weight savings of up to 80% compared to steel cables, with nearly the same breaking strength and comparable diameter, allow for an increase in the load-bearing capacity or permissible lifting load, as the rope's own weight, which must be considered for load-bearing capacity, is significantly lower. Particularly in cranes with great lifting heights or in booms or mast extension systems with pulleys of high reeving ratios, considerable rope lengths and thus corresponding rope weights are required, making the weight reduction possible with high-strength fiber ropes highly advantageous.In addition to the weight advantage of the fiber rope itself, its use also allows for weight savings in other components. For example, the load hook can be made lighter, as a lesser load hook weight is sufficient to tension a fiber rope in a rope drive. Furthermore, the good flexibility of synthetic fiber ropes allows for smaller bending radii and thus smaller sheaves or pulleys on the crane, leading to further weight reduction, particularly in the area of ​​the crane boom. This enables a significant increase in load moment and peak load capacity for large crane reaches.

[0003] In addition to the aforementioned weight advantages, rope drives with synthetic fiber ropes offer significantly longer service life, ease of handling, good flexibility, and eliminate the need for rope lubrication, which is required with steel ropes. Overall, this results in improved equipment availability.

[0004] High-strength fiber ropes, like steel ropes, are wear parts that must be replaced when their condition deteriorates to such an extent that continued operation no longer guarantees the required safety. This condition is generally referred to as the point of discard. However, a challenge with such high-strength fiber ropes lies in precisely and reliably predicting when they reach the point of discard. With conventional steel ropes, the point of discard can be determined relatively easily by visually inspecting the rope's condition, with the testing procedure and scope specified in the ISO 4309 standard. Essentially, this involves assessing the number of wire breaks over a specific length of the rope, a reduction in rope diameter, and strand breaks.However, this measurement method is not suitable for determining the end of its service life in high-strength fiber ropes, as the synthetic fibers used do not behave like steel wire strands. In particular, high-strength fiber ropes often fail suddenly or reach the end of their service life without any gradual, detectable damage, because, unlike steel ropes, individual fibers often do not break and fray gradually; instead, several fiber strands often fail simultaneously.

[0005] German patent application DE 20 2009 014 031 U1 discloses a high-strength synthetic fiber rope in which a rope core is covered with a sheath that is colored differently than the core and itself has several layers of different colors. This multicolored sheathing is intended to make it easier to see when an outer layer wears away, revealing a differently colored layer underneath or even the core. In practice, however, this otherwise useful color indicator function is hampered by the fact that, due to the properties of high-strength synthetic fibers, the sheath tends to fail quite suddenly, making it difficult to reliably predict when the rope will need to be discarded.

[0006] EP 1 930 497 A and EP 1 930 496 A disclose the use of an electrically conductive indicator fiber that has lower abrasion resistance than the load-bearing strands or fibers of the rope. Damage to or breakage of the indicator fiber can be detected by conductivity measurements. This approach is disadvantageous because it requires additional conductivity measurements and, consequently, the necessary technical infrastructure such as a power source, a conductivity meter, and connection points for the indicator fiber.

[0007] From DE 20 2013 101 326 U1, the use of an electrically conductive sensor filament is known with the same disadvantages.

[0008] Methods are also known that use the elongation of the rope over its service life as an evaluation criterion for the condition of the rope and for predicting when it is ready for disposal, and which determine this in various ways, for example from EP 0 731 209 A and EP 2 002 051 A. In the latter document, markings are provided on the sheath of a core-sheath rope (e.g., braided sections made of differently colored material) by means of which elongation or twisting of the rope can be determined.

[0009] WO 2003 / 054290 A1 proposes a ferromagnetic material which should also allow for the detection of local damage to the rope.

[0010] WO 2012 / 162556 discloses a rope with one or, optionally, several sheath layers, wherein in at least one sheath layer the fibers forming the strands are dispersed in a resin matrix in the form of fiber bundles, i.e., as plied, untwisted yarn. A resin matrix modifies the properties of the fibers and protects them from wear. WO 2012 / 162556 also proposes indicator fibers capable of transmitting electrical or optical signals to signal when the rope needs to be discarded.

[0011] Further prior art is known from US 2003 / 111298, JP 2001 / 192183, WO 2004 / 029343, US 2005 / 226584, EP 1 905 892, WO 2015 / 139842, EP 1 530 040, US 2003 / 06225, US 2003 / 06226, JP H10 318741, DE 22 22 312 A and US 6 321 520 B1.

[0012] The use of fibers with different elongation behavior in a rope is described in DE 24 55 273 B2 and is intended to ensure that all strand layers of the rope bear the load, but not to indicate wear.

[0013] US Patent 7,127,878 B1 describes a rope made of at least two materials with different tensile strengths, with the first material bearing the tensile load during normal operation. In the event of tensile overload of the rope, material 2 assumes the tensile load of material 1, thus preventing total rope failure. However, this does not affect the detection of wear by abrasion, particularly in rope drives where the rope is bent over pulleys.

[0014] US Patent 2013 / 247536 A1 describes a high-strength fiber rope for use in nautical applications. A thicker strand, preferably made of polyurethane, is optionally woven into the sheath of this rope. Discard criteria for this rope cannot be determined gradually, as the sheath will fail abruptly.

[0015] Documents FR 2 410 077 A1, US 2014 / 178615 A1, and DE 296 08 971 each depict core-sheath ropes, but these are not made of high-strength fibers. Furthermore, the sheaths of these ropes, due to their simple construction, would also be prone to abrupt failure.

[0016] DE 10 2015 017 157 A1 discloses a high-strength fiber rope, wherein the sheathing has several sheath layers which differ from each other with regard to their fiber structure and the abrasion and / or tensile strengths and / or flexural fatigue strengths of the plastic fibers used in the sheath layers.

[0017] In contrast, the present invention is based on the objective of creating an improved high-strength fiber rope that avoids the disadvantages of the prior art and advantageously develops the latter further. In particular, it aims to enable a simple, yet reliable and precise determination of the discard stage and thus the longest possible service life, without compromising the safety of the fiber rope.

[0018] The aforementioned problem is solved according to the invention by a high-strength fiber rope according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0019] The sheathing of the high-strength fiber rope according to the invention comprises at least one braided sheath layer made of at least two interwoven textile subunits of a first hierarchy level, wherein optionally a part of the textile subunits of the first hierarchy level comprises at least two textile subunits of a second hierarchy level, which in turn optionally comprise at least two textile subunits of a third hierarchy level.

[0020] For the sake of clarity, the subunits of the first hierarchy level will be abbreviated as 1TUE, the subunits of the second hierarchy level as 2TUE, and the subunits of the third hierarchy level as 3TUE.

[0021] For example, the at least two 1TUE can be in the form of strands, ropes, threads, cords, ribbons, and / or yarns that are interwoven. Depending on the design of the 1TUE, these can in turn be formed from at least two, preferably several, twisted, braided, knitted, crocheted, woven, and / or substantially parallel 2TUE. For example, a 1TUE in the form of a strand or rope can itself be formed from several threads, cords, ribbons, and / or yarns.

[0022] Depending on the design of the 2TUE, these can in turn be formed from at least two, preferably several, twisted, braided, knitted, crocheted, woven and / or substantially parallel 3TUE. For example, a 2TUE in the form of a rope, a thread, a cord or a band is itself formed by several yarns, which then constitute the 3TUE.

[0023] For the purposes of the present invention, the fiber bundles used to construct the textile subunits, in particular plied, i.e. untwisted yarns, are defined as the lowest hierarchical level of the rope according to the invention.

[0024] The sheathing of the high-strength fiber rope according to the invention is formed by an outermost layer and a further sheathing layer arranged below the outermost layer. The further sheathing layer is arranged between the rope core and the outermost sheathing layer, and may completely or only partially enclose the rope core.

[0025] In a casing with an outermost layer and a further layer arranged beneath it, the further layer can either be located directly beneath the outermost layer or separated from it by one or more separating layers, which are particularly prone to rapid wear. A separating layer could, for example, be a thin film made of a plastic material.

[0026] The textile subunits of the lowest hierarchy level of the rope are not dispersed in a resin matrix in the outermost sheath layer or in the further sheath layer arranged below the outermost sheath layer, as provided for in WO 2012 / 162556.

[0027] Preferably, all textile subunits of the rope consist essentially of textile fiber material. This means that none of the textile subunits of the rope are dispersed in a resin matrix. This does not preclude the optional presence of only a surface impregnation of subunits (see below).

[0028] The 1TUE and / or, if present, the 2TUE of the outermost layer differ from each other in terms of their textile construction and consequently exhibit different abrasion resistances.

[0029] The term "textile construction" of the 1TUE and / or, if present, the 2TUE, generally refers to the textile arrangement and structure of the subunits or the subunits underlying them. For the purposes of the present invention, the term "textile construction" does not include the properties of the materials used to construct the rope, i.e., the plastic fibers, such as their chemical nature, fineness (thickness), abrasion and / or tensile strength, and / or flexural fatigue strength.

[0030] However, apart from the specific structure of the subunits, "textile construction" also includes textile parameters of the subunits such as the presence of impregnation or reinforcement.

[0031] The different textile constructions of the textile subunits, as provided for in the invention, result in different wear resistances of the subunits, independent of the properties of the respective fiber material used. Thus, textile subunits of different constructions wear differently even under uniform exposure to wear-promoting influences. This results in different, visually detectable changes in the sheathing under stress. According to the invention, the wear resistance of the sheathing of the core-sheath rope is therefore primarily altered by the change in the textile construction of the 1TUE and / or, if present, the 2TUE, and not by the properties of the material of the plastic fibers used.

[0032] The 1TUE and / or, if present, the 2TUE differ advantageously from each other in their construction in at least one of the following properties: Type of construction: Possible construction methods for subunits include twisting, braiding, knitting, weaving, or parallel arrangement of the subunits forming the respective subunit at a lower hierarchical level. For example, a 1TUE can be constructed from at least two, and in particular several, intertwined, twisted, knitted, woven, and / or parallel 2TUE units. A second 1TUE can have a different construction than the first 1TUE, meaning that the 2TUE units in the second 1TUE are structured differently than those in the first 1TUE. This applies analogously one hierarchical level lower, i.e., for 2TUE units, which can be constructed differently from the respective 3TUE units. Technical parameters of the construction: "Technical parameters of the construction" refer, in particular, to parameters influencing the wear resistance of a given construction (e.g., braiding or twisting).A technical parameter of a twisted textile subunit is, for example, the beating angle. Technical parameters of a braided textile subunit include, for example, the braiding angle or the braid density. Braid density refers to the number of bobbins from which strands or yarns are fed into the braiding machine. If applicable, the number of 2TUE per 1TUE: For example, a textile subunit with otherwise identical construction and material can be more wear-resistant if a higher number of 2TUE per 1TUE is provided. Accordingly, for example, a 1TUE formed by a strand can exhibit higher wear resistance if the strand has a higher number of 2TUE formed by, for example, yarns, than another 1TUE.If present, the number of 3TUE per 2TUE; and the presence, type, and / or quantity of impregnation in one or more subunits: Impregnation can modify the surface hardness and / or surface roughness of the textile subunits. For example, impregnation can increase or decrease the wear resistance of textile subunits as required. Impregnations can, in a known manner, comprise materials from the group consisting of polyurethanes, waxes, silicones, and mixtures thereof. For the purposes of the present invention, "impregnation" is understood to mean the mere surface application of impregnating material to the respective textile subunit. Complete dispersion of textile subunits, particularly textile subunits of the lowest hierarchy level, in a resin matrix does not constitute impregnation within the meaning of the present invention.

[0033] All of the above-mentioned possibilities for different textile constructions can of course be combined with each other.

[0034] Examples of the different structures of textile subunits at the various hierarchy levels: Part of each 1TUE is twisted, and another part is braided. Each 1TUE is twisted, with the degree of twist in one part being greater than the degree of twist in another part. The difference in twists per meter can preferably be at least 40 T / m (e.g., one part of the subunits with 20 T / m and another part with 60 T / m or more).

[0035] In the above embodiments, different constructions are present in the first hierarchy level of the rope, specifically in the type of construction of the 1TUE itself or parameters of the construction of the 1TUE (e.g. extent of the rotation).

[0036] In the following embodiments, the differences in construction lie in the second hierarchy level of the rope, i.e., at 2TUE: Each 1TUE is twisted, with the degree of twist of the 2TUE used to form the 1TUE being greater in one part of the 1TUE than in another part. Preferably, the difference in twists per meter can be at least 40 T / m. 1TUE is formed from a plurality of substantially parallel 2TUE units, wherein in one part of the 1TUE the 2TUE units are braided and in another part the 1TUE the 2TUE units are twisted. Alternatively or additionally, in the 1TUE, a portion of the parallel 2TUE units can be twisted and another portion braided, wherein the respective number of twisted and braided 2TUE units, or the degree of twist, or the braiding angle of the 2TUE units differs in one part of the 1TUE from another part.1TUE are formed from a plurality of substantially parallel adjacent 2TUE, wherein the 2TUE are rotated and wherein in one part of the 1TUE the 2TUE are rotated more strongly than in another part of the 1TUE.

[0037] Once again, all of the above-mentioned options can be combined with each other.

[0038] Another difference may lie in the presence, type, and extent of impregnation or reinforcement in a part of the 1TUE or 2TUE.

[0039] The textile construction of the textile subunits is advantageously chosen such that, based on wear and tear occurring over the service life of the high-strength fiber rope and the resulting visual changes in the sheath, a reliable determination can be made as to whether the high-strength fiber rope has reached the end of its service life. Damage to the outermost sheath layer typically occurs only partially and gradually, so that, based on the progressively increasing number of damaged areas, different wear states of the high-strength fiber rope and the associated remaining distance to the point of being deemed unfit for service can be gradually determined and quantified.

[0040] The determination of when a rope should be discarded can be carried out by a qualified person using a visual inspection based on reference images of the rope at different levels of damage or based on their experience. Therefore, it can be determined macroscopically. The qualified person should ideally categorize the damage found, document it in writing, and summarize it in order to then determine the discard criteria. Alternatively, the discard criteria can be determined using software, in which case the sheathing is optically scanned using camera systems.

[0041] The preferred method is to use a textile construction for the 1TUE and / or, if applicable, the 2TUE, individually adapted and defined for each rope. This has the advantage of creating a reliable indicator for each rope, individually tailored to its intended use, location, and type of load, allowing for a quick and easy determination of whether the rope has reached the end of its service life.

[0042] In the case of a sheathing of the high-strength fiber rope according to the invention with an outermost layer and a further sheathing layer arranged below the outermost layer, not only do the 1TUE and / or, if present, the 2TUE differ from each other with regard to their textile construction in the individual layers, but also the 1TUE and / or, if present, the 2TUE of the outermost sheathing layer differ from that of the further sheathing layer in their textile construction.

[0043] Each sheath layer, due to the different textile constructions of its sub-units, exhibits a characteristic resistance to abrasion and wear. This results in a partially different damage pattern in each layer, or causes the sheath layers to wear at different rates. For example, visually apparent wear on the outermost sheath layer may indicate that the rope is nearing the end of its service life, although the actual end of the service life is only reached when visually apparent wear is visible on the inner sheath layer. This allows sufficient time to ensure that a new rope is ordered or provided. Until delivery, the rope can still be used, with the inner sheath layer providing a reliable indicator of whether the rope is still fit for purpose.

[0044] In other words, by simply changing the textile construction of the textile subunits of the sheathing, the wear resistance of the sheathing of the high-strength fiber rope according to the invention can be changed and adapted to a service life of the high-strength fiber rope such that it can be reliably determined by an optical assessment of the sheathing when the high-strength fiber rope has reached its discard maturity.

[0045] In addition, different types of plastic fibers can be used in the textile subunits to change the wear resistance of the coating, thus increasing the differences between the wear resistances of the textile subunits.

[0046] The plastic fibers underlying the sheathing of the high-strength fiber rope according to the invention can be, for example, HMPE fibers, polyester fibers, polyamide fibers, PBO fibers and / or aramid-carbon fiber blends.

[0047] Furthermore, if an additional sheath layer is present in the outermost sheath layer, plastic fibers can be provided that differ from at least some, and in particular all, of the plastic fibers in the additional sheath layer with regard to their fineness and / or abrasion and / or tensile strength and / or flexural fatigue strength and / or their material. The extent of the different wear resistances resulting from the different construction of the textile subunits according to the invention is thus further increased by different material properties.

[0048] Advantageously, in a high-strength fiber rope according to the invention with a sheath that comprises the further sheath layer, the sheath has sheath layers of different thicknesses and / or plastic fibers of varying thicknesses from layer to layer. By using plastic fibers of different thicknesses, different damage patterns can be achieved from layer to layer, even with the same or similar textile construction. Furthermore, by using different layer thicknesses, which can increase, for example, from the outside to the inside, it can be ensured that increasingly deeper damage becomes progressively more difficult to detect, while initially only minor damage, which is still relatively far from the point of discard, first appears on the outer layer and is thus easily recognizable.

[0049] To facilitate the identification of different types of damage, even minor ones, the textile subunits of the various hierarchy levels, which exhibit different abrasion resistances, can be dyed in different colors. Alternatively, the plastic fibers from which the textile subunits of the lowest hierarchy level are formed can be dyed in different colors.

[0050] In a high-strength fiber rope according to the invention, with a sheath comprising an outermost sheath layer and a further sheath layer arranged below it, the sheath layers can be colored with different colors. This significantly facilitates the visual detection of damage to the sheath due to wear, since when the outermost sheath layer is worn, the further sheath layer arranged below it becomes visible in a different color or color combination.

[0051] In particular, the rope core may also have a different color than the sheathing, especially a different color than the further sheathing layer or the outermost sheathing layer of the sheathing, so that at the latest when the sheathing is completely worn away, the different color of the rope core becomes visible.

[0052] According to the invention, the sheathing of the high-strength fiber rope according to the invention has at least one additional further sheathing layer, which are arranged one above the other, each at least partially overlapping, between the rope core and the outer sheathing layer.

[0053] Furthermore, it is possible that in the high-strength fiber rope according to the invention the sheathing is at least partially impregnated, that a reinforcement surrounding the outermost sheathing layer is formed at least partially around the sheathing, and / or that a thin film surrounding the outermost sheathing layer is formed at least partially around the sheathing.

[0054] A high-strength fiber rope according to the invention, as described above, is advantageously used as part of a lifting device, particularly in cranes such as tower cranes, telescopic cranes, harbor cranes, or ship cranes. It is preferably designed as a crane hoist rope or as a crane boom guy rope.

[0055] Preferably, the sheathing of the rope is not designed to bear weight.

[0056] The invention is explained in more detail below with reference to preferred embodiments and accompanying drawings. The drawings show: Figs. 1 to 7: each show a section of the sheathing of an embodiment of a high-strength fiber rope according to the invention. For clarity, the 1TUE figures are shown in only one braiding direction (here S). All embodiments refer analogously to the second braiding direction (here Z).

[0057] Figures 1 to 7 Each figure shows a section of an embodiment of a high-strength fiber rope according to the invention. Each of the high-strength fiber ropes is made from a section of the Figures 1 to 7The rope consists of an invisible core and a sheath surrounding the core, the sheath being formed directly around the core or optionally separated from it by an intermediate layer. The core can bear the entire specified tensile strength of the fiber rope. The sheath can, in particular, form the outer sheath of the fiber rope and acts primarily as a support and protection for the core. The sheath has an outermost layer formed from interwoven 1TUE subunits in a braided diamond pattern. The 1TUE and / or, if present, the 2TUE subunits differ from one another in their textile construction, resulting in different wear resistances of the subunits, from which the wear condition of the rope can be visually determined.

[0058] In none of the depicted design variants is a resin matrix provided in any of the jacket layers in which the TUE of the lowest hierarchy level are dispersed.

[0059] Specifically, it shows: Figure 1 An embodiment of a high-strength fiber rope 1 according to the invention. The outermost sheath layer 2 is formed by two interwoven 1TUE, which are in the form of twisted ropes 3, 4 made of yarns (not shown). The ropes 3, 4 thus form the 1TUE of the rope, and the yarns used to twist the ropes form the 2TUE of the rope.

[0060] Rope 3 has a rotation X and rope 4 has a different rotation Y.

[0061] Advantageously, the rotation X of rope 3 can be 20 T / m and the rotation Y of rope 4 60 T / m or more.

[0062] This therefore represents a different construction (here: extent of rotation) in the plane of the 1TUE.

[0063] The plastic fibers of the yarn underlying rope 3 can either be made of the same material as the plastic fibers of the yarn underlying rope 4, or they can be made of different materials. For example, the plastic fibers used in rope 3 can be made of polyester fibers, and the plastic fibers used in rope 4 can be made of HMPE fibers.

[0064] Furthermore, alternatively or additionally to this embodiment, it is possible that the yarns forming the ropes 3 are provided with an impregnation, while this is not the case for the yarns forming the ropes 4.

[0065] Alternatively or additionally, the number of threads forming rope 3 may differ from the number of threads forming rope 4. Figure 2a further embodiment of a high-strength core-sheath rope according to the invention 5.

[0066] The 1TUE are present in the form of strands 7 and 8.

[0067] Strands 7 and 8 are each formed from several 2TUE units arranged essentially parallel to each other. The 2TUE units of strands 7 and 8 are connected by... Figure 2 Twisted yarns (not shown in detail) are formed, and exhibit a rotation X in strand 7 and a rotation Y different from X in strand 8.

[0068] Advantageously, the rotation X can be 20 T / m and the rotation Y 60 T / m or more.

[0069] This therefore involves a different construction (here: extent of rotation) in the plane of the 2TUE. This requirement could of course also be additionally addressed in the embodiment according to Figure 1 be provided for.

[0070] Alternatively or additionally to this embodiment, it is also possible that the number of yarns forming the strands 7 differs from the number of yarns forming the strands 8. Figure 3 Another embodiment of a high-strength fiber rope 9 according to the invention. The outermost sheath layer 10 is formed by two interwoven 1TUE in the form of rope 11 and rope 12.

[0071] Rope 11 is made from several twisted strands (2TUE).

[0072] Rope 12 is braided from several strands of yarn (2TUE).

[0073] Therefore, ropes 11 and 12 have different structures.

[0074] Again, the plastic fibers used in rope 11 can either be made of the same material as the plastic fibers used in rope 12, or the material of the plastic fibers can be different. For example, the plastic fibers used in rope 11 can be made of PBO fibers and the plastic fibers used in rope 12 can be made of aramid fibers. Figure 4 Another embodiment of a high-strength fiber rope 13 according to the invention. The outermost sheath layer 14 is formed by two interwoven 1TUE units 15 and 16, which are in the form of strands 15 and 16. The strands 15 and 16 are each formed from several 2TUE units arranged side by side in a substantially parallel manner.

[0075] The 2TUE of strands 15 are twisted together with a turn X.

[0076] The 2TUE of strands 16 are intertwined.

[0077] Alternatively, a portion of the 2TUE units present essentially parallel to each other in 1TUE 15 and 16 can be twisted, and another portion can be braided, with the respective number of twisted and braided 2TUE units, or the degree of twist or braiding angle of the 2TUE units, differing between different parts of 1TUE. For example, 1TUE 15 could contain 3 braided and 2 twisted 2TUE units, and 1TUE 16 could contain 2 braided and 3 twisted 2TUE units, essentially parallel to each other.

[0078] Additionally or alternatively, it is possible that the 2TUE are each formed from a different number of 3TUE. Figure 5 Another embodiment of a high-strength fiber rope 17 according to the invention. The outermost sheath layer 18 differs from the outermost sheath layer 14 of the high-strength fiber rope 13 shown in Figure 4in that the bobbin lace sequence of the 1TUE is different.

[0079] In the Figures 1 to 5 Two subunits with different designs are shown. This results in a two-stage wear process of the outermost shell layer, which can be visually detected. Figure 6 Another embodiment of a high-strength fiber rope 19 according to the invention. The high-strength fiber rope 19 differs from the high-strength fiber rope 2 shown in Figure 2 in that the high-strength fiber rope 19 has a further 1TUE in the form of a strand 21 in its outermost sheath layer 20.

[0080] Strand 21 is formed from several 2TUE strands arranged essentially parallel to each other, which are interwoven.

[0081] The rope according to this embodiment thus has two strands 7 and 8, whose 2TUE are twisted to different degrees, and a further strand 21, whose 2TUE are interwoven. This results in a three-stage wear of the outermost sheath layer 20, which is visually detectable.

[0082] The plastic fibers used in strand 21 can be made of the same material as the plastic fibers in strands 7 and 8, or they can be made of a different material. Figure 7 Another embodiment of a high-strength fiber rope 22 according to the invention. The outermost sheath layer 23 is formed by four interwoven 1TUE. The 1TUE are formed by strands 24, 25, 26 and 27.

[0083] Strands 24, 25, 26, and 27 each have several 2TUE units arranged essentially parallel to each other. The 2TUE units are each formed by plies, which in turn consist of several 3TUE units. The 3TUE units are formed by yarns. The plies of strand 24 are twisted with a twist X, the plies of strand 25 are braided with a braiding angle A, the plies of strand 26 are twisted with a twist Y other than X, and the plies of strand 27 are braided with a braiding angle B other than A.

[0084] This results in a four-stage process of coat wear, which can be visually detected.

[0085] It should also be noted that details of the design variants are shown in the Figures 1 to 7 They can be combined with each other in any way, which allows for the creation of further design variants.

[0086] Furthermore, it should be noted here that the sheathing of the in the Figures 1 to 7 In the described embodiments of the high-strength fiber rope according to the invention, a further sheath layer is arranged below the outermost sheath layer, which can be designed according to one of the described outermost sheath layers or can also have a different number of 1TUE and / or optionally 2TUE and / or optionally 3TUE with different textile construction.

[0087] Furthermore, it should be noted that the plastic fibers in the sheath layers may differ in thickness and / or that the sheath layers may differ in thickness.

Claims

1. High-strength fibre cable (1) for hoisting equipment such as cranes, with a rope core comprising high-strength plastic fibres or strands, and a sheath surrounding the rope core and visually indicating wear, wherein the sheath has at least one sheath layer (2) comprising at least two interwoven textile subunits (3, 4) of a first hierarchical level, and wherein, optionally, a part of the textile subunits (3, 4) of the first hierarchical level comprises at least two textile subunits of a second hierarchical level, which in turn optionally may comprise at least two textile subunits of a third hierarchical level, wherein an outermost sheath layer and a further sheath layer arranged below this are provided, wherein the outermost sheath layer comprises the at least two interwoven textile subunits (3, 4) of the first hierarchical level, and wherein the textile subunits of the first hierarchical level and / or, if present, the textile subunits of the second hierarchical level of the outermost sheath layer differ from those of the further sheath layer in their textile construction and, as a result, have different wear resistances, characterised in that the textile subunits of the lowest hierarchical level of the rope are not dispersed in a resin matrix in either the outermost sheath layer or in the further sheath layer arranged below the outermost sheath layer, and that the textile subunits (3, 4) of the first hierarchical level and / or, if present, of the second hierarchical level differ from each other in at least one of the following properties with regard to their textile construction, whereby the term "textile construction" does not include the properties of the materials used to construct the rope: - type of construction; - technical parameters of the construction, in particular braiding or lay angle; - if present, number of textile subunits of the second hierarchical level per textile subunit (3, 4) of the first hierarchical level; - if present, number of textile subunits of the third hierarchical level per textile subunit of the second hierarchical level; - presence of a reinforcement; and - presence and / or type and / or quantity of impregnation.

2. High-strength fibre cable (9) according to claim 1, wherein, in the outermost sheath layer (2), textile subunits (3, 4) of the first hierarchical level and / or, if present, textile subunits of the second hierarchical level differ from each other in their textile construction and, as a result, have different wear resistances.

3. High-strength fibre cable (9) according to any one of claims 1 or 2, wherein one of the at least two textile subunits (12) of the first hierarchical level is braided and another one of the at least two textile subunits (11) of the first hierarchical level is twisted.

4. High-strength fibre cable (1) according to any one of claims 1 or 2, wherein at least two textile subunits of the first hierarchical level (3, 4) are twisted, wherein one of the at least two textile subunits (3) of the first hierarchical level is twisted more than another of the at least two twisted textile subunits (4) of the first hierarchical level.

5. High-strength fibre cable (13) according to any one of the preceding claims, wherein at least part of the textile subunits (15, 16) of the first hierarchical level is formed from a plurality of substantially parallel juxtaposed subunits of a second hierarchical level, wherein at least one of the textile subunits of the second hierarchical level is braided and at least one other of the textile subunits of the second hierarchical level is twisted.

6. High-strength fibre cable (5) according to any one of the preceding claims, wherein at least a portion of the textile subunits (7, 8) of the first hierarchical level is formed from a plurality of substantially parallel subunits of a second hierarchical level, wherein at least some of the textile subunits of the second hierarchical level are twisted and wherein at least some of the twisted textile subunits of the second hierarchical level are twisted more than other textile subunits of the second hierarchical level.

7. High-strength fibre cable according to one of the preceding claims, wherein, if the further sheath layer is present in the sheathing, plastic fibres are provided in the outermost sheath layer which differ from at least some of the plastic fibres of the further sheath layer in terms of their fineness and / or abrasion and / or tensile strength and / or flexural fatigue strength and / or their material.

8. High-strength fibre cable according to one of the preceding claims, wherein, if the further sheath layer is present in the sheathing, the sheathing has sheath layers of different layer thicknesses and / or plastic fibres of different thicknesses from layer to layer.

9. High-strength fibre cable according to one of the preceding claims, wherein textile subunits having different wear resistances are dyed in different colours.

10. High-strength fibre cable according to one of the preceding claims, wherein the rope core has a colour that differs from that of the sheathing.

11. Hoisting equipment, in particular a crane such as a tower crane, telescopic crane, harbour crane or ship crane, with a high-strength fibre cable (1) configured in accordance with any one of the preceding claims.

12. Hoisting equipment according to claim 10, wherein the high-strength fibre cable (1) forms a crane hoisting cable or a crane jib tensioning cable.