CN107109786B

CN107109786B - Elevator rope and method for manufacturing the same

Info

Publication number: CN107109786B
Application number: CN201580069168.0A
Authority: CN
Inventors: V·范沃森霍夫; H·罗美尔
Original assignee: Bekaert Advanced Cords Aalter NV
Current assignee: Bekaert Advanced Cords Aalter NV
Priority date: 2014-12-19
Filing date: 2015-12-01
Publication date: 2020-11-06
Anticipated expiration: 2035-12-01
Also published as: WO2016096395A1; EP3233702A1; EP3233702B1; FI3233702T3; CN107109786A; ES2954911T3

Abstract

An elevator rope (100) includes a steel cord (114) and an elastomeric jacket (140) surrounding the steel cord. One or more yarns (120, 122) are wrapped or braided or knitted around the steel cord prior to application of the elastomeric jacket. The yarn is thus integrated into the polymer jacket. The yarns induce a pattern in the surface of the polymer jacket. By modifying the yarn structure, the surface pattern of the polymer jacket can be changed. This has an effect on the friction of the elevator rope on the sheave on which it runs. Thus, the integrated yarns help maintain the integrity of the elastomeric jacket. In a second aspect of the invention, a method is claimed, wherein one or more yarns are first wound, braided or knitted around a steel cord before extrusion of the elastomer. The mantle ensures good centricity of the elastomeric sheath and improved processability of the elevator rope.

Description

Elevator rope and method for manufacturing the same

Technical Field

The present invention relates to elevator ropes for use in elevators for personnel, goods, storage and any other application similar thereto. Furthermore, a method for producing such an elevator rope is disclosed.

Background

This motivated a series of innovations in the elevator field in the european union when "european parliament and council directive 95/16/EC member country like act on elevators" in 6 th 1995, on year 7-1 th 1997. Since the ban on fine high tensile wires as loaded in EN 81-1 is now removed, other different tension members can be evaluated with these kinds of wires.

Essentially two development trajectories occur. In a first trajectory, the steel cord is replaced by a thin strip comprising several thin steel cords built of thin and high tensile filaments and encased in a polymer sheath (WO 99/43589). In the second trajectory, smaller diameter steel cords with or without a polymer coating are used (EP 1213250). Both enable the use of smaller drive rollers and pulleys and hence the use of a "direct drive" motor, which in turn makes the entire hoisting machine compact and light and thus enables the installation of the elevator without a machine room at the top of the building. The invention relates to this second development trajectory in relation to the deformation of a steel cord with a polymer jacket.

The lateral pressure in the steel wire rope increases as a result of the increased pressure between the rope and the sheave caused by the decrease in diameter of the sheave and rope (as the load force remains constant and the contact surface is reduced). Since fine high tensile strands are more prone to breakage when under lateral pressure, it is now common to use elastomeric jackets to relieve the lateral pressure by spreading it throughout the elevator rope.

Furthermore, since the contact surface between the elastomeric jacket and the sheave is smaller than when using a thick wire rope on a large diameter sheave, the coefficient of friction between the sheave and the coated wire rope must be increased to generate sufficient clamping force. The presence of the elastomeric jacket has a profound effect on the friction between the coated steel cord and the sheave. The coefficient of friction between the sheave and the elastomer jacket is more likely to be 1.0 and even higher than the coefficient of friction between the steel cord and the steel sheave of the prior art, which is about 0.1.

However, too high friction leads to other problems:

when the car is in its upward run and the counterweight is blocked in its movement or reaches its buffer, the car will be lifted further by the drive sheave, while the ropes on the counterweight side are slack, possibly pushing the car against the top of the hoistway;

when a passenger's car is in its down run and an emergency stop occurs (e.g., due to a power outage), the passenger may experience an unpleasant downward acceleration because the elevator ropes are too much caught in the sheaves.

Furthermore, since friction occurs between the surfaces of two different parts (pulleys and elevator ropes), the two surfaces must be adapted, adjusted to each other in order to obtain the most appropriate friction conditions. There is therefore a need to be able to adapt at least one of the surfaces to an optimal friction value with the other surface. Since the total surface of the elevator rope is larger than the surface of the sheave that is in repeated contact with the rope, it is preferable that the surface of the rope is adaptable while the surface of the sheave remains wear resistant.

Different solutions have been proposed in order to adapt the friction of the elastomeric sheath to the pulley:

JP2004131897 describes a wire rope with a resin coating layer, wherein the coating layer has a cross-sectional profile deviating from a true circle over at least a part along the length direction of the rope. For example, a plurality of grooves or ridges may extend along the length of the cord.

DE 102012015580 describes a cord with an elastomeric sheath having at least two regions on the outer surface with different coefficients of friction. By varying the area ratio or the difference in friction between the two regions, it becomes possible to adjust the coefficient of friction of the rope.

US 2011/0192131 relates to an elevator rope having a main rope body covered with a jacket. The jacket consists essentially of a thermoplastic polyurethane elastomer blended with one or more of the following:

-an isocyanate compound having two or more isocyanate groups per molecule or;

-a thermoplastic resin other than the thermoplastic polyurethane and an isocyanate compound having two or more isocyanate groups per molecule or;

-inorganic fillers in fibrous or platy form.

WO 2013/053621 describes a load bearing assembly for use in an elevator system, comprising at least one steel cord surrounded by a thermoplastic elastomer comprising polymer particles having a molecular weight of more than 500000 g/mol.

Another problem that sometimes occurs with high tensile cords having elastomeric sheaths is that shear forces in the elastomer can rise above tear forces and cracks can occur in the coating due to compression of the sheath and/or relative movement of the strands during use.

The present invention therefore seeks other ways to address the friction and cracking problems.

Disclosure of Invention

The invention aims to provide an elevator rope with friction with a pulley capable of being adjusted at will. It is a further object of the invention to provide an elevator rope having a specific coefficient of friction with the sheaves of an elevator. It is another object of the present invention to provide a reinforced elastomeric jacket that reduces cracking of the polymer. A method for producing such an elevator rope is also the subject of the present invention.

According to a first aspect of the invention, an elevator rope is provided comprising a steel cord and an elastomeric sheath surrounding the steel cord. What is specific about the elevator rope is that it further comprises one or more yarns wound, braided or knitted around the steel cord. These one or more yarns are integrated into an elastomeric sheath. One or more yarns wound, braided or knitted around the steel cord form a pattern on the steel cord that emerges, progresses, appears, imprints or reaches the surface of the elevator rope through the polymer jacket.

The load bearing member of the elevator rope is a steel cord, i.e. a cord comprising a plurality of steel filaments. For the purposes of this application, steel cords (generally considered to be of a larger size, e.g. greater than 8mm) are also considered steel cords. Furthermore, the use of non-metallic fibers in steel cords is not per se excluded. The steel cord may comprise other fibres than steel filaments. In any case, the greatest part of the load on the steel cord must be carried by the steel filaments. Alternatively, the steel cord may consist of only steel filaments. The elevator rope preferably comprises one single steel cord. In contrast to the belt tension member of WO99/43589, in which the thickness of the tension member is smaller than the width, the elevator ropes have a substantially circular cross-section.

In order to limit the diameter of the elevator rope, the monofilaments have a high tensile strength. Tensile Strength "Rm" (in N/mm) of Steel monofilaments²Or MPa) is its breaking load (in units of N) divided by its cross-sectional areaIn mm²In units). For the purposes of this application, in N/mm²The tensile strength expressed is greater than 3000-2000 x, where "" is the equivalent diameter of a steel monofilament in mm, i.e., the diameter of a round monofilament having the same cross-sectional area as the monofilament. Currently, even higher tensile strengths are considered, such as above 3500-. It is envisaged that the diameter of the filaments for the steel cord is between 0.15mm and 0.50mm, or more preferably between 0.20mm and 0.40 mm. Therefore, the tensile strength of the monofilament is higher than 2000N/mm². Different filament diameters are generally used within the steel cord of the invention in order to have the filaments and the strands fit together geometrically in the steel cord.

To achieve these high tensile levels, plain carbon steel is used which is sufficiently cold deformed by wire drawing. A typical steel composition has a minimum carbon content of 0.65%, a manganese content ranging from 0.40% to 0.70%, a silicon content ranging from 0.15% to 0.30%, a maximum sulfur content of 0.03%, a maximum phosphorus content of 0.30%, all percentages being percentages by weight. With only minor amounts of copper, nickel and/or chromium.

The outer surface of the monofilament is preferably coated with a functional coating to promote adhesion and/or to retard corrosion and/or to improve fatigue wear. Where a rubber elastomer sheath is envisaged, the adhesive coating is for example brass plated steel monofilament which adheres well to rubber. Optionally organofunctional silanes, titanates or zirconates may be used to improve adhesion to the polyurethane. The latter may conveniently be combined with a zinc coating which also brings about and improves the corrosion resistance. Optionally mineral or synthetic oils (preferably compatible with the elastomer of the sheath) may be used, which reduce abrasion between the filaments and at the same time inhibit corrosion.

The steel cord is preferably a multi-strand steel cord composed of strands of steel filaments. Preferred embodiments have core strands made of two, three or more strands. Another preferred embodiment wherein the cord comprises a central core strand surrounded by a layer of inner strand forming the inner strand. The outer layer steel wire strand is cabled on the inner strand layer. The lay lengths and directions of the inner layer strand and the outer layer strand are preferably different from each other and/or opposite to each other. Typically, the lay length of the inner ply is chosen between 5 and 12 times the diameter of the inner ply and the lay length of the outer ply is chosen between 5 and 15 times the diameter of the steel cord. The lay length of the outer ply is the cord lay length.

The number of inner strands is from 5 to 8 and the number of outer strands is from 6 to 12. In a preferred embodiment, there is no common divisor between the number of inner strands and the number of outer strands. This results in a smaller interlaminar pressure between the strands.

The strands are steel monofilaments twisted together. The stranding can be done in a single step, wherein all steel filaments of the strand obtain the same lay length and direction. A simple construction with equal diameters, such as three filaments twisted together (3 x 1) or six filaments surrounding a single core (1+6), is preferred for the core and the inner strand. The pitch of the filaments in the strands is from 10 to 20 times the diameter of the strands. Strands with high metal fill factors are more preferred for the outer strands because they are the highest in number and must withstand most of the load. It is most preferred that the monofilament diameter is selected according to the warrington, west-gule (sea), packed or warrington-west-gule configuration. Exemplary configurations are 1+6-6-6 warrington, 1+6+6F +12 pad, 1+9-9 West. These configurations have a metal fill factor of 75% or higher.

Alternatively, the strands may be of a multi-layer type. In a multilayer type of strand, the core strand or monofilament is covered with a layer of monofilament having a different lay length and/or direction compared to the substrate layer. Multilayer strands are somewhat less preferred due to point contact between their monofilaments and a lower metal fill factor.

The diameter "d" of the steel cord does not limit the invention in principle. The invention may use steel cords having a diameter of from 1mm to 20mm or even more. Preferably, the diameter "d" of the steel cord is less than 8mm, even more preferably less than 7mm, such as e.g. 4.5mm, 5mm, 5.5mm or 6 mm. The invention can be advantageously used starting from a diameter of 2mm and higher, thus not excluding the use of steel cords below this limit.

In order to spread and reduce the pressure on the high tensile steel filaments, the elevator rope is provided with an elastomeric jacket completely surrounding and encasing the steel cords. The elastomer may for example be a heat-hardened elastomer like rubber. Rubber has some specific advantages: it is wear resistant and enables very good adhesion to brass coated monofilaments. However, it generates a lot of friction with other objects, making it less preferred for the coating of elevator ropes. Also, vulcanization of the rubber requires a large amount of energy and is an additional step to extrusion.

More preferred are therefore thermoplastic elastomers that can be easily extruded around steel cords and do not require an additional vulcanization step. Furthermore, the coefficient of friction with steel pulleys is lower than the coefficient of friction with rubber and steel pulleys.

Typical thermoplastic elastomers may be selected from the group consisting of styrene block copolymers, polyether-ester block copolymers, thermoplastic polyolefin elastomers, thermoplastic polyurethanes, and polyether polyamide block copolymers. Examples of thermoplastic polyurethanes include ether-based polyurethanes, ester-ether-based polyurethanes, carbonate-based polyurethanes, or any combination thereof. Preferred polyurethanes are those with good hydrolysis resistance and low temperature flexibility, such as ether-based polyurethanes.

The coefficient of friction (static or dynamic) of the elastomeric jacket can also be modified by adding fillers to the elastomeric compound. Particularly notable fillers are spherical or non-spherical high molecular weight polymer particles having a size of between 5 μm and 500 μm or between 20 μm and 250 μm or most preferably between 50 μm and 100 μm. The high molecular weight polymer is, for the purposes of this application, a polymer having a molecular weight of greater than 0.5X 10⁶g/mol, e.g. in the range of 1X 10⁶g/mol and 15X 10⁶g/mol or more preferably between 2X 10⁶g/mol and 9X 10⁶Polymers of molecular weight between g/mol. Particularly preferred particles are ultra high molecular weight polyethylene (UHMW-PE) particles or ultra high molecular weight polydimethylsiloxane particles.

As mentioned, elevator ropes comprise yarns wound, braided or knitted around steel cords.

Within the scope of the present application, by "yarn" is meant any type or kind of non-metallic filament, i.e. an elongated, strong monofilament, strand or cord purposely designed for use in weaving, sewing or other textile work. They may be made of a single monofilament or a plurality of monofilaments or fibers spun together (spun yarn) or twisted together without intentional twisting (zero twist yarn). The yarns may also be in the form of narrow strips or bands of material.

The yarn may be made of an artificial, i.e. synthetic, material selected from the group consisting of glass fibers, polyaramid fibers, poly (p-phenylene-2, 6-benzobisoxazole) fibers, polyurethane fibers, carbon fibers, polyolefin fibers, polyamide fibers, polyester fibers, polycarbonate fibers, polyacetal fibers, polysulfone fibers, polyetherketone fibers, polyimide fibers, polyetherimide fibers or mixtures thereof.

Alternatively, the yarn may be made of natural or semi-synthetic fibers selected from the group consisting of sisal, flax, cotton, hemp, silk, basalt, cellulose-based fibers, or mixtures thereof. Rayon is a specific example of a semi-synthetic regenerated cellulose fiber.

Yarns based on blends or blends of synthetic, semi-synthetic or natural fibers may also be advantageously used. Alternatively, combinations of said synthetic, semi-synthetic and natural yarns are of course also possible, for example wherein one yarn is synthetic and the second yarn is based on natural fibres.

The yarn may be provided with an adhesive sizing, a coating that improves adhesion to the elastomer of the sheath. In the case of rubber, RFL (resorcinol formaldehyde latex) impregnation is recommended. In the case of thermoplastic elastomers, aqueous sizing solutions based on starch, acrylic polymers, polyvinyl alcohol or others, dissolved in hot water together with waxes, such as polyolefin waxes, are recommended. After impregnation and drying, a layer is formed on the yarn. Non-aqueous sizing including hot melt polymers and waxes such as polyolefin waxes are also contemplated. Examples of hot melt polymer sizes are acrylates or methacrylates. It is best if the yarn material adheres to the polyurethane without the need for a sizing, for example when the yarn and jacket elastomer are polyurethane-based.

The yarn is wrapped around the steel cord by looping, winding, spiraling the yarn around the steel cord. The winding may be done in the direction of cord twist or in a direction opposite to the direction of cord twist. It is possible that more than one yarn may be wound around with the same yarn lay length, or that the yarns may have different yarn lay lengths and/or may be wound in opposite directions. The wound yarns can be easily unwound from the steel cord by unwinding them in the reverse order or in the opposite direction: they will not tangle.

Alternatively, the yarns may be braided around the steel cord. In the weaving operation, two or more yarns are wound around the steel cord, at least one of which is wound opposite the other. Again, the yarns have a yarn lay length equal to the axial distance required by making one turn of the yarn around the steel cord. At least one of the yarns alternately crosses under and over one or more of the remaining yarns. This results in a weave pattern on the surface of the steel cord. Preferably, the number of yarns paid out in one winding direction is equal to the number of yarns running in the opposite direction. All kinds of weaving are possible, like plain, twill or satin weaving. The individual yarns will not easily loosen from the resulting weave.

In a third alternative, the yarns are knitted or stitched around the steel cord. Preferably, this is done during the warp knitting or stitching process. The individual knitted or stitched yarns do not fully circumscribe the steel cord. However, the yarn lay length may still be defined as the distance between two contacts of the same pair of yarns. One, two or more yarns may be knitted or stitched around the steel cord. Removal of a single yarn causes the other yarns to loosen.

In a more preferred embodiment, the individual lay length of the one or more yarns is shorter than the cord lay length of the steel cord. This ensures that the yarns cross the outer strands of the steel cord at an angle and that the yarns are not oriented parallel to the strands.

In another preferred embodiment, at least two yarns are wound around the steel cord in opposite directions. When the lay lengths of oppositely running yarns are equal, crossover will always occur diametrically opposite and at the same circumferential position. This results in a repeating pattern of protrusions on the surface of the elastomer. Alternatively, when the windings have mutually prime lay lengths (e.g. 15mm and 14mm or 5mm and 9mm) to each other, the crossovers will not occur in diameter with each other and spread evenly around the circumference of the steel cord. It is also possible that the lay length varies along the length of the steel cord. Winding is the preferred method for applying the yarn because it operates at the highest linear speed.

The winding, weaving or knitting should not completely cover the steel cord. In contrast: it is intended that a sufficient portion of the steel cord remains open for entry of the elastomeric jacket to integrate and unite the elevator rope. The yarn is thus embedded in and an integral part of the elastomeric sheath. As such, the yarn reinforces the elastomeric sheath and prevents it from cracking during prolonged use.

A further purpose of the yarn is to introduce controlled unevenness into the outer surface of the elastomeric sheath. This controlled unevenness affects the friction coefficient of the elevator rope. At the yarn crossings, i.e. where the thickness of the yarn is doubled, small bulges at the surface of the elastomeric sheath occur. Since the amount and location of these intersections can be controlled, the number of protrusions at the surface of the elastomeric jacket can also be controlled.

The open yarn layer further improves the mechanical anchoring of the sheath to the steel cord. Preferably less than 60% of the outer surface of the steel cord is covered with one or more yarns. If the degree of coverage is too high, the yarns will isolate the polymer jacket from the steel cords, thereby compromising the integrity of the elevator rope. Too high a degree of coverage also results in a too smooth surface of the elastomeric jacket. At least 5% of the surface must be covered with yarn in order to have at least a beneficial effect. If not enough yarn is present, the jacket surface will remain unaffected and the reinforcement of the jacket will be insufficient. Other possible degrees of coverage are between 5% and 50% or between 10% and 50%, or between 15% and 45%.

Also, the yarns must diffuse sufficiently into each other so that the individual yarns themselves should not cover too much of the steel cord surface. The width of the yarns should therefore be less than 30%, or even less than 20% of the diameter of the steel cord. The width of the yarn is the dimension in the direction perpendicular to the yarn when it is in position on the steel cord, since the yarn can flatten during winding, braiding or knitting. At the other end of the range, the thickness of the yarns is preferably more than 1%, or even more than 5% of the diameter of the steel cord, in order to leave sufficient impression on the outer surface of the polymer jacket.

Furthermore, the thickness of the wound, woven or knitted yarn should neither be too large nor too small compared to the thickness of the elastomeric sheath. The thickness of the elastomeric sheath is equal to half the difference between the diameter of the elevator rope and the diameter of the steel cord measured with the elastomeric sheath. These diameters are measured with a micrometer having a large gauge head. By "large gauge head" is meant a circular gauge head having a diameter at least larger than the cord lay length of the steel cord. As "diameter", the average of the minimum and maximum measured values across the circumference of the elevator rope or steel cord is used. Thus, the sheath thickness also includes the thickness of the yarn.

The thickness of the elastomeric sheath is between 5% and 50% of the diameter of the steel cord, with a more preferred thickness being between 5% and 30% or between 5% and 25%.

By thickness of the yarn is meant the radial dimension of the individual yarn when in position around the steel cord. This thickness of the yarn is less than the thickness of the elastomeric sheath. The yarns must be covered by polymer at least when the elevator rope is in its newly made state. During use, some of the yarns may be exposed to the surface of the elastomeric jacket. Preferably, the thickness of the yarn is less than 75% of the thickness of the elastomeric sheath. The yarn should also have a minimum amount of thickness, for example 5% of the elastomeric sheath. This is to continue the embossing of the yarn to the surface of the elastomeric sheath. Other advantageous ranges are: between 10% and 60%, between 10% and 50%.

Due to the controlled roughness of the surface, not all of the elastomer will come into contact with the surface of the pulley. The portions of the polymer jacket that are present under the yarns will be more easily contacted by the flat surface than the valleys in the polymer jacket. The yarn pattern allows control of the contact surface. The contact surface of the elastomeric jacket with the flat surface can be determined by laying the elevator rope across a width of 100mm under a diametric force of 10N onto the flat surface (e.g., by inking the elastomeric surface or by using pressure sensitive paper). By varying the yarn pattern, an oscillating elastomeric jacket contact surface of between 10% and 90% can be achieved. An advantageous range is between 10% and 60% of the elastomeric sheath contacts the flat surface when unrolled. The optional range is between 10% and 50%, between 15% and 40%, or between 20% and 40%.

The elevator rope is intended for use in elevators for cargo and/or elevators for personnel. Its size and strength as described above makes it possible to use with small drive pulleys, enabling the use of a direct drive motor without a gearbox. The elevator rope may be used with pulleys having a diameter "D" equal to or less than 40 x D, where "D" is the diameter of the steel cord.

According to a second aspect of the invention, a process or method is described for manufacturing an elevator rope as described above. The process starts with providing a steel cord of the size and geometry as disclosed above. Continuously applying yarns around the steel cord in one or more of the following ways:

by winding one or more yarns around the steel cord. When two or more yarns are present, the wrapping may be done in opposite directions. Preferably, the winding is done with a lay length shorter than the lay length of the steel cord. It is also preferred that the lay lengths of the oppositely running yarns are different. Existing winding machinery can be used for this purpose.

By weaving two or more yarns around the steel cord. The two sets of oppositely running yarns alternately cross over and under each other during weaving, thereby forming a weave pattern. The weave should be open. Typically, a five pole type (maypole) or a high speed braider (as known e.g. in hose manufacture) may be used for this purpose.

By knitting. At least two yarns are held to each other at the stitching during knitting. The yarns do not completely enclose the steel cord but only a corner portion thereof. Existing circular knitting machines can be used for this purpose.

In this way an intermediate product of the steel cord with an open mantle is obtained. The intermediate product is further extruded with an elastomer sheath, whereby the elastomer enters between the open mantle and penetrates even further into the steel cord, whereby the mantle is integrated into the polymer sheath.

The process has several advantages over the prior art. First, the mantle improves the drag of the polymer during extrusion. The surface of the elevator rope thus obtains a substantially circular cross-section. The centricity of the steel cords in the elevator rope is also improved.

Second, the mantle prevents the steel cord strand from forming a sleeve during extrusion. Due to the large pressure exerted on the steel cords during extrusion, the outer strands tend to be pushed back at the entrance of the extrusion head. This push back causes an accumulation of extra length of the outer strand, thereby opening the steel cord. This may even lead to breakage of the steel cord if the two outer strands exchange positions. The presence of the mantle prevents the outer strands from accumulating extra length and thus prevents the occurrence of sleeve formation.

In the following sections, the invention will be further elucidated by means of examples and embodiments. The examples are not limiting of the invention and are merely meant to illustrate how the invention may be reduced to practice.

Drawings

Fig. 1a shows the first embodiment in longitudinal direction and fig. 1b shows the same embodiment in cross section.

Fig. 2a shows the second embodiment in longitudinal direction and fig. 2b shows the same embodiment in cross section.

Fig. 3a shows a third embodiment in longitudinal direction and fig. 3b shows the same embodiment in cross section.

Fig. 4a, 4b and 4c show surface impressions of the surfaces of different elevator ropes according to the invention.

In the drawings, reference numerals having equal units and tens digits indicate identical elements throughout the figures designated with thousands digits.

Detailed Description

In a first example of the invention (fig. 1a and 1 b), steel cords of the following type are made:

{[(0.34+6×0.31)_12.5s+6×(0.25+6×0.25)_12.5z]_25s+

7×(0.34+6×(0.31|0.33|0.25)_20s}_50Z

around a central core wire of diameter 0.34, 6 wires of diameter 0.31 were twisted in the "s" direction with a lay length of 12.5. On this core strand, 6 inner layer strands were cabled at a lay length of 25 in the s direction (with 0.25 core filaments, around which 0.25 core filaments, 6 outer filaments of 0.25 twisted at a lay length of 12.5 in the z direction). Seven outer strands twisted in parallel in a waring swallow configuration with 0.34 core filaments surrounded by 6 0.31 filaments, folded at a lay length of 50 in the Z direction, and 6 alternating filaments of 0.33 and 0.25 twisted at a lay length of 20 in the "s" direction over the 6 0.31 filaments, are finally wrapped around the core strand. Thus 50 is the cord lay length. All dimensions are in millimeters. The filaments are made of plain carbon steel having a far-drawn carbon content of more than 0.70 wt% C. The tensile strength of the monofilament was 2200N/mm depending on the size of the monofilament²To 2900N/mm²In the meantime. The monofilaments are hot dip galvanized. A cross section of the steel cord is indicated with 110 in fig. 1 b. The steel cords have a diameter of 5.1 mm.

Two spun yarns of polyethylene terephthalate (a polyester-based thermoplastic polymer) of 90 tex (g/km) were wound around the steel cord. First a yarn 122 having a lay length of 6.1mm in the "s" direction, followed by a yarn 120 having a lay length of 5.1 in the "z" direction. The diameter of the intermediate product after winding is 5.3mm to 5.4 mm. The degree of surface coverage was estimated to be at 15%, the width of the monofilament was 0.35mm and the thickness of the monofilament was 0.15 mm. Thus, an elliptical cross-section is obtained during winding of the monofilament;

the intermediate product was directed through an impregnation tank containing a solution of 1.5 volume percent N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (the functionalized organosilane) dissolved in a mixture of isopropanol and water. The impregnation was followed by air drying.

The intermediate product was further processed in an extrusion line and made of clear polyurethane (Bayer AG)

) And (4) coating. This forms an elastomeric sheath 140, which elastomeric sheath 140 follows the texture of the backing yarn and exhibits a reverseThe uneven surface of the substrate mantle is mirrored. The final outer diameter of the cord is 5.65mm, so that the thickness of the elastomeric sheath is 0.275mm or 5.4% of the diameter of the steel cord.

The "surface impression" is made of the outer surface of the elastomeric sheath by: by taking a 10cm long test piece from the elevator cord, inking the outer surface and spreading it over a piece of paper, while applying a diameter force of 10N to the test piece. The surface impression is shown in fig. 4 b. A 1200dpi digitized image was made from the surface impression and the number of non-white pixels relative to the total number of pixels was counted. In this case 17% of all pictures show the color, i.e. 17% of the surface of the elastomeric sheath contacts the flat surface. Furthermore, fig. 4b shows the differences; a semi-regular pattern reflecting the distribution of the yarns embedded in the elastomeric sheath.

In a second alternative embodiment (depicted in fig. 2a and 2 b), the steel cord comprises a core strand of type 1+6 surrounded by 5 inner strands, also of type 1+ 6. The outer layer comprised 7 strands of 19 monofilaments in a waring swallow configuration. The cords also had a diameter of 5.1 mm.

In this embodiment 4 yarns 220, 220 ', 222' are woven around the steel cord. Yarns 220, 220 'twist in the Z direction, while yarns 222, 222' twist in the S direction. The yarns cross each other in a plain weave (one under and one over). Each yarn has a lay length of 10.2mm but since there are four yarns, the axial distance between two consecutive yarns is only 2.55 mm. The yarn was polyphenylene sulfide (PPS) monofilament yarn with a diameter of 0.20 mm. The coverage of the surface of the steel cord was 9.3%.

The intermediate product is again treated with the same binder and used

And (4) coating. The resulting elevator rope had a diameter of 5.65mm, such that the elastomer jacket thickness was 0.275mm or 5.4% of the steel cord diameter. The ratio of yarn thickness to elastomeric sheath thickness is therefore 73%.

The resulting fingerprint of the surface of the elastomeric sheath is shown in fig. 4 a. The ratio of the contact surface to the circumferential surface of the elastomeric jacket is 24%.

The steel cord 310 of the third embodiment 300 as represented in fig. 3a and 3b is made according to the following formula:

{[(0.44+6×0.37)_7z+12×0.34]_14z+6×[(0.34+6×0.31)_10s+12×0.29]_20s}_50Z

that is, the core strand and the outer strands are multilayer strands in which the core filaments are surrounded by six outer filaments at a first lay length, which in turn are surrounded by twelve outer filaments wound at a second lay length. The monofilament has a thickness of 2300N/mm²And 2700N/mm²Tensile strength in between.

The steel cord 310 is surrounded by cellulose based rayon fibers twisted into individual yarns having a linear density of 248 tex. Three

yarns

320, 322 and 324 are knitted around the steel cord 310, each of the yarns covering a respective radial segment of about 120 °. The yarn exhibits a lay length "L" equal to the axial contact distance between pairs of contacts of the yarn.

The steel cords with yarns being reused from Bayer

And (4) coating. The cords show an uneven surface with a regular pattern: fig. 4 c.

Claims

1. An elevator rope comprising a steel cord and an elastomeric jacket surrounding the steel cord, the elevator rope having a substantially circular cross-section,

it is characterized in that the preparation method is characterized in that,

the elevator rope further comprises one or more yarns wound, woven or knitted around the steel cord,

wherein the one or more yarns wound, braided or knitted around the steel cord form a pattern on the steel cord that penetrates through the polymer jacket to the surface of the elevator rope, the one or more yarns being integral with the elastomeric jacket.

2. The elevator rope according to claim 1, wherein the steel cord has a steel cord diameter, and wherein the elastomeric jacket has a thickness of between 5% and 50% of the steel cord diameter.

3. The elevator rope according to claim 1, wherein the steel cord comprises strands twisted around each other with a cord lay length, the one or more yarns being wound, braided or knitted around the steel cord with a lay length shorter than the cord lay length.

4. The elevator rope according to claim 1, wherein at least two of the plurality of yarns are wound in opposite directions.

5. The elevator rope according to claim 4, wherein the at least two yarns are wound with a lay length that is relatively prime to each other.

6. The elevator rope according to any one of claims 1 to 5 wherein the one or more yarns have a width of less than 30% of the diameter of the steel cord.

7. The elevator rope according to any one of claims 1 to 5 wherein the one or more yarns cover less than 60% of the outer surface of the steel cord.

8. The elevator rope according to any one of claims 1 to 5 wherein the thickness of the one or more yarns is greater than 5% of the thickness of the elastomeric jacket.

9. The elevator rope according to claim 1, wherein the one or more yarns are made of a synthetic material selected from the group consisting of: glass fibers, polyaramid fibers, poly (p-phenylene-2, 6-benzobisoxazole) fibers, polyurethane fibers, carbon fibers, polyolefin fibers, polyamide fibers, polyester fibers, polycarbonate fibers, polyacetal fibers, polysulfone fibers, polyetherketone fibers, polyimide fibers, polyetherimide fibers, or mixtures thereof.

10. The elevator rope according to claim 1, wherein the one or more yarns are natural material based fibers selected from the group consisting of sisal, flax, cotton, hemp, silk, basalt, or regenerated cellulose fibers or mixtures thereof.

11. The elevator rope of claim 1, wherein the elastomeric jacket is a thermoplastic elastomer selected from the group consisting of styrene block copolymers, polyetherester block copolymers, thermoplastic polyolefin elastomers, thermoplastic polyurethanes, and polyetherpolyamide block copolymers.

12. The elevator rope according to claim 11, wherein the elastomeric jacket is a thermoplastic polyurethane comprising an ether polyurethane, an ester ether polyurethane, a carbonate polyurethane, or any combination thereof.

13. The elevator rope according to claim 11 or 12, wherein the thermoplastic elastomer further comprises polymer particles having a molecular weight of at least 500000 g/mol.

14. The elevator rope according to claim 1 wherein said steel cords are treated with an adhesive selected from the group consisting of organofunctional silanes, organofunctional titanates or organofunctional zirconates to improve adhesion to said elastomeric jacket.

15. The elevator rope according to claim 1, wherein the one or more yarns are provided with a sizing for improving adhesion to the polymer jacket.

16. The elevator rope of claim 1, wherein between 10% and 90% of the surface of the elastomeric jacket is in contact with a flat surface when unrolled across a length of 100mm under a diameter force of 10N.

17. Method to manufacture an elevator rope according to any of claims 1 to 16, comprising the steps of:

-providing a steel cord;

-continuously winding or braiding or knitting one or more yarns around said steel cord, thereby forming an intermediate product of steel cord with an open mantle;

-extruding the intermediate product with an elastomer sheath of substantially circular cross-section, whereby elastomer enters between the open mantle;

it is characterized in that the preparation method is characterized in that,

the one or more yarns are integrated into the elastomeric sheath and wherein the one or more yarns wound, braided or knitted around the steel cord form a pattern on the steel cord that penetrates through the polymer sheath to the surface of the elevator rope.