EP2476801A2 - Rope, combined rope made of artificial fibres and steel wire strands and combined strand of artificial fibres and steel wires - Google Patents

Abstract

The cable has a twisted monofilament bundle or multiple twisted monofilament bundles made of high-strength plastic fibers and are enclosed in a braided casing (2). The monofilament bundles are stretched to reduce the diameter. The core cable (1) is a combined cable whose outer external layer is made of steel wire strands (4). Independent claims are also included for the following: (1) a combined cable with a core cable (2) a combined cord with a core.

Description

The invention relates to a rope made of high-strength plastic fibers, which are present as a, in particular twisted, monofilament bundle or a plurality of twisted monofilament bundles, which is or are enclosed by a sheath.

In particular, the invention relates to a combined rope with a core rope made of high-strength plastic fibers and an outer layer of steel wire strands.

Furthermore, the invention relates to a combined strand with a core made of high-strength plastic fibers and an outer layer of steel wires.

Ropes of the aforementioned type, in particular for sports purposes, known by use with a plastic fibers protecting braid.

A combined rope of the aforementioned type is known from the US 4,887,422 with a sheathing of the core rope which is extruded or wound up.

A combined strand of the aforementioned type is not prior art.

The advantage of the high-strength plastic fibers is their low weight and volume compared to their strength both in the independent ropes and in the combined ropes and strands.

This advantage is particularly effective for long-length ropes for hanging use, such as mining ropes or deep-sea ropes. Because in such an application, the weight of a pure wire rope itself already claimed a large part of its load capacity: the payload is correspondingly limited.

Advantage of the combined rope over the pure plastic rope is its significantly lower sensitivity to mechanical interference. In addition, it can be seen on the visible wire breaks the Ablegereife a wire rope in good time.

While the breaking strength of high strength plastic fibers, eg aramid copolymer 3470 N / mm ² , aramid HM (high modulus) 2850 N / mm ² , aramid HS (high strenth) 3350 N / mm ² , aramid SMS (standard modulus) 2850 N / mm ² , HMPE 3400 N / mm ² and Liquid Crystal Polyester 2800 N / mm ² , which exceeds that of steel wire, eg 1770 N / mm ² , and thus can contribute decisively to the load bearing capacity of a combined rope, but the strains differ in this way high degree that under the known rope constructions hardly a rope structure can be found, in which the core rope made of plastic can take a significant share of the load bearing. The elastic moduli of the above fiber materials are 73, 120, 60, 60, 85 and 65 GPa, respectively, compared to an average of 200 GPa of steel wires. Above all, there is the fact that the actual load absorption of the plastic fibers begins with a delay, because the monofilament bundles first have to "settle" with each load, ie have to find a final spatial allocation to form a stable bundle cross section.

The invention has for its object to increase the effective carrying capacity of a core rope of plastic fibers in a combined rope or, based on the plastic rope itself, to increase the carrying capacity in a different sense.

According to the invention, this purpose is fulfilled by the fact that in a rope of the type mentioned, the or monofilament bundles stretched under diameter reduction and is held in this state by the sheath or are.

Like a corset, the sheath fixes the cross-section of the monofilament bundle assumed during said stretching. Thus, the process of "setting" before and at the beginning of the load pickups is at least largely eliminated, he is finished once and for all. The normal load absorption under elastic stretching of the plastic fibers according to Hooke's law can start immediately.

In a combined rope, the stretching behavior of the core rope is thus approximated to that of the steel wire layer.
An independent rope has the same carrying capacity, for example, reduced by 10% diameter, ie a greater load capacity based on the diameter.

As a variant and a particularly advantageous development of the invention, it is proposed to approximate the stretching behavior of the steel wire layer of a combined rope to that of the core rope made of synthetic fibers by subjecting the steel wire layer to the reversal version of the invention taken on the core rope: it is to be able to stretch under load and to do so permitting variable cross-section.
The concrete measure of invention in this version is that the cable has an intermediate layer of an elastic plastic, in which the wire strands are pressed with a distance from each other, such that the outer layer stretches under load and contracts radially.
The elastic compliance of the intermediate layer and the distance of the wire strands from each other make it possible to stretch the helices described by the strands by increasing their pitch, with their diameter and accordingly reduces the strand spacing.
Due to the elasticity of the plastic, the process is reversible when relieved, so the desired effect with each new load absorption available.

The advantages of the former version and the reverse version of the invention can each be used individually, but with great success, together.

Analogous to the combined rope, a combined strand can be created. At the point of the core wire of the strand is then just as the core rope of the strand ausgestaltetes, but correspondingly thinner rope. (The term "rope" includes strands of monofilament bundles, regardless of structure.)

As the sheath mentioned is particularly suitable a braid. In a braiding machine, the monofilament bundles can simply be stretched by being driven at the exit of the machine, for example by a pair of rollers for their movement be retained at the input of the machine, for example by means of a braked pair of rollers, and the braid can be carried out with a bias voltage. However, wrapping is also an option.
If necessary, the expansion can also be effected by reducing the cross-section.

The said intermediate layer is usually, as in the art propagated, be extruded, possibly on the said sheath. A standardization of the sheathing and the intermediate layer would be difficult in that both serve different purposes and must therefore have different properties. The sheathing should be as unyielding as possible, the intermediate layer should be soft. Foamed plastic is also considered for the intermediate layer.
Suitable materials for the sheath are, for example, polyester fibers, suitable materials for the intermediate layer are polyurethanes, polyesters, polyolefins and polyamides.

Finally, as a particularly advantageous application of a core rope according to the invention, a combined rope is mentioned for hanging use over a large height difference, in particular with a lower end held against rotation, in particular a hoist rope, deep-sea rope or cableway rope which is characterized by change in length over the rope length in that the load-specific torque of the wire rope decreases upward.

A wire of this structure is known from the DE 36 32 298 , which is hereby incorporated into the disclosure of the present application.
With the above-mentioned stroke length changes caused by the rope weight twists within the rope structure can be avoided, in particular further twists of the strand layer in the lower region of the rope, which would seek to shorten the rope there and thus counteract the load of the core rope.

Fig. 1

ist ein Last-Dehnungs-Diagramm verschiedener Materialien,

Fig. 2

ist ein Last-Dehnungs-Diagramm einer normal verseilten und einer erfindungsgemäß auf einer elastischen, weichen Zwischenschicht verseilten Stahldrahtlage,

Fig. 3

ist ein Last-Dehnungs-Diagramm eines Kernseiles aus Kunststofffasern für ein kombiniertes Stahldraht-Kunststofffaser-Seil mit und ohne erfindungsgemäße Ummantelung,

Fig. 4

ist ein Last-Dehnungs-Diagramm des Kernseiles und der Drahtseillage eines kombinierten Seiles wie nach Fig. 5,

Fig. 5

zeigt einen Querschnitt eines kombinierten Seiles mit einem Kernseil aus Kunststofffasern und einer Außenlage aus Stahldrahtlitzen und

Fig. 6

zeigt einen Querschnitt eines Fig. 5 entsprechenden Seiles mit anderen Litzen.

In the following, the invention will be explained in more detail by way of examples.

Fig. 1

is a load-elongation diagram of different materials,

Fig. 2

FIG. 2 is a load-elongation diagram of a normally stranded and a steel wire layer stranded on an elastic, soft intermediate layer according to the invention, FIG.

Fig. 3

FIG. 3 is a load-elongation diagram of a core rope of plastic fibers for a combined steel wire-plastic fiber rope with and without sheath according to the invention, FIG.

Fig. 4

is a load-elongation diagram of the core rope and the wire rope layer of a combined rope as below Fig. 5 .

Fig. 5

shows a cross section of a combined rope with a core rope of plastic fibers and an outer layer of steel wire strands and

Fig. 6

shows a cross section of a Fig. 5 corresponding rope with other strands.

In Fig. 1 the relevant materials are each noted directly on the curves. The steel wire follows Hooke's Law only in the lower load range because it is made by drawing and therefore does not have the normal structure. The use is usually only about in the lower half of the curves.

In Fig. 2 you can find the curve of the steel wire in Fig. 1 in the normally stranded strand layer (upper curve) again. The lower curve shows the effect of embedding the strands according to the invention in a soft intermediate layer: up to about 0.6% elongation, the curve runs approximately horizontally. The elongation here is that the helixes of the coiled strands elongate, reducing the diameter of the helices, almost without load-bearing of the strands. The load pickup sets in afterwards.

How out Fig. 3 can be seen, the above-mentioned, pronounced up to 0.5% and then decreasing, but noticeably still up to about 1% elongation effecting act of setting (lower curve) largely by the sheath invention eliminate (upper curve). The upper curve increases in contrast to the lower from the beginning, although the final proportional slope according to the Hooke's law only about between 0.5 and 1% elongation occurs.

The application of both invention measures in a combined rope as after Fig. 5 is out Fig. 4 seen. Here are the lower curve of the Fig. 2 and the upper curve of the Fig. 3 close to each other.

In cross-section of the rope construction Fig. 5 the inventive measures can only be seen insofar as a sheath 2 of a core rope 1 and also an intermediate layer 3 are shown, in which an outer layer of steel wire strands 4 is pressed.
The core rope 1 is within the sheath 2 of a monofilament bundle or more monofilament bundles, which are only twisted so much that they have cohesion and can be handled. The sheath 2 consists of a braid of preferably polyester threads. It sits with a bias on the Monofilbündel or monofilament bundles, which holds them together after an elongation in the set state.
The intermediate layer 3 is extruded over the sheath 2 of the core rope 1 in a conventional manner. It consists of a soft-elastic plastic, such as polyethylene or polypropylene.

The steel wire strands 4 are stranded over and pressed eg in the still warm intermediate layer 3 such that they have each their own bed with some distance from each other.
The intermediate layer 3 is so elastic-soft and the steel wire strands 4 have such a distance from each other (slightly larger than in the drawing), that the position of the steel wire strands 4 under load initially somewhat lengthy and their diameter is reduced. The strain curves ( Fig. 4 ) of the strand layer and the core rope are thereby approximated to each other, ie the load bearing is distributed approximately corresponding to the cross sections of the strand layer and the core rope.

The rope according to Fig. 6 has the same basic structure as the one according to Fig. 5 with a core rope 1, a braided sheath 2, an extruded intermediate layer 3 and an outer algae of here designated 5 strands. The strands 5 have an analog to the rope structure again with a thinner, core 6 of high strength plastic fibers, a braided sheath 7, an extruded intermediate layer 8 made of a soft elastic plastic and an outer layer of steel wires 9. The rope has due to its larger Plastic cross-section the advantage of even lower weight, but it is also robust with the steel wires in the outer layer.
The intermediate layer 3 could also be omitted in this rope, since the outer strands 5 already have an increased elasticity in itself.

Claims (15)

A combined rope having a core rope of high strength plastic fibers and an outer layer of steel wire strands, the core rope being in the form of a monofilament bundle, in particular a twisted monofilament bundle or a plurality of monofilament twisted bundles, enclosed by a sheath,
characterized,
in that the monofilament bundle or bundles (1; 6) are stretched under diameter reduction and held in this state by the sheath (2; 7). Combined rope according to claim 1,
characterized,
that the or Monofilbündel (1; 6) is stretched in such a way or are that the monofilaments have found their final spatial relationship to form a stable bundle cross-section and an assumed in the stretched state cross-section of Monofilbündels (1; 6) through the jacket (2; 7) is held. Combined rope according to claim 1 or 2,
characterized by an intermediate layer (3) made of an elastic plastic, in which the steel wire strands (4; 5) are pressed in at a distance from each other, such that the outer layer stretches under load and contracts radially. A composite stranded wire having a core strand of high strength plastic fibers and an outer layer of steel wires, the core strand being in the form of a monofilament bundle or a plurality of monofilament bundles, in particular twisted monofilament bundles and enclosed by a sheath, the monofilament bundle (1; Diameter reduction stretched and held in this state by the sheath (2, 7) is or are. Combined strand according to claim 4,
characterized,
in that the monofilament bundle (s) (1; 6) is stretched such that the monofilaments have found their final spatial association to form a stable bundle cross-section and one in the expanded one Condition assumed cross-section of the monofilament bundle (1, 6) by the sheath (2, 7) is held. Combined strand according to claim 4 or 5,
characterized by an intermediate layer (8) of elastic plastic, in which the steel wires (9) are pressed with a distance from each other, such that the outer layer stretches under load and contracts radially. Combined cable according to one of claims 1 to 3 or combined strand according to one of claims 4 to 6,
characterized,
that the sheath (2) is braided or wound. Combined strand according to one of claims 4 to 6,
characterized,
that it is outer strand (5) of a combined rope comprising a core rope (1) made of high-strength plastic fibers and an outer strand layer. Combined cable according to claim 3 or combined strand according to claim 6,
characterized,
that the intermediate layer (3; 8) is extruded. A combined rope according to claim 3, 7 or 9, or combined strand according to claim 6, 7, 8 or 9,
characterized,
that the intermediate layer (3; 8) of a plastic foam, is formed of a polyurethane, a polyester, a polyolefin or a polyamide. Combined rope according to claim 1, 2, 3, 7 or 9,
characterized,
that it is his rope for a hanging use over a large height difference, in particular a hoist rope, deep-sea rope or cable car rope that is characterized by change in length over the rope length such that the load-specific torque of the wire rope decreases upward. Rope of high strength plastic fibers present as one, in particular twisted, monofilament bundle or a plurality of monofilament twisted bundles enclosed by a sheath,
characterized,
in that the monofilament bundle or bundles (1; 6) are stretched under diameter reduction and held in this state by the sheath (2; 7). A rope according to claim 12,
characterized,
that the sheath (2) is braided or wound. A rope according to claim 12 or 13,
characterized,
that it is core rope (1,2) of a combined rope having an outer layer of steel wire strands (4; 5). A rope according to claim 12 or 13,
characterized,
it is core (6,7) of a combined strand having an outer layer of steel wires (9).

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