DE102019217625A1 - Elevator belt with cords made of coated strands - Google Patents

Abstract

Elevator belt made of elastomeric material, which has embedded tensile or strength members running in the longitudinal direction of the belt, which are designed in the form of cords from one or more strands, the strands being made up of filaments provided with a coating around a filament serving as a strand core arranged, preferably laid, characterized in that the filament (king filament) forming the strand core is provided with a thicker coating than the filaments surrounding the strand core.

Description

The invention relates to an elevator belt made of elastomeric material, which has embedded tensile or strength members running in the longitudinal direction of the belt, which are designed in the form of cords from one or more strands, the strands being made up of filaments provided with a coating, which are formed around a arranged as a strand core serving filament, preferably laid.

For some time now, the steel ropes that were previously used exclusively in elevator technology have been increasingly being replaced by belt-like suspension means, namely by elevator belts. Such elevator belts can be designed as flat belts, V-ribbed belts or otherwise profiled belts made of elastomeric material and are provided with tension members or reinforcements that are embedded within the elastomeric material in the longitudinal direction of the elevator belts and essentially absorb the tensile forces.

The tension members can consist of different materials, but are usually thin steel cords which on the one hand are completely enclosed by the elastomeric material and on the other hand are protected from corrosion by a coating. In the case of steel cords, this is usually a relatively thin zinc coating.

The steel cords usually consist of individual strands wrapped around one another, which in turn consist of several twisted or wrapped filaments.

During the operation of the elevator belts and during the alternating bending of the elevator belt or the steel cords under load via deflection and support rollers, the individual filaments move relative to one another and friction occurs between the individual filaments. The resulting abrasion is called "fretting". As a result of this friction of the individual filaments against one another, the relatively thin coating of the filaments, in the case of steel cords or steel filaments, the zinc coating can be rubbed off. The friction of steel on steel that then sets in with galvanized steel cords creates a so-called “friction rust”. This is undesirable and hinders the proper operation of an elevator.

The object of the invention was therefore to provide an elevator belt which does not have this tendency to form frictional rust or only to a lesser extent and thus allows a longer operating time before the so-called discard condition is reached, i.e. the elevator belt has to be replaced.

This problem is solved by the features of the main claim. Further advantageous designs are disclosed in the subclaims.

The filament that forms the stranded core, which is called “king filament” in technical jargon, is provided with a thicker coating than the filaments surrounding the stranded core. Surprisingly, through investigations and test bench runs, it was found that the abrasion caused by fretting was already minimized when the strand cores and the surrounding strands are provided with different layer thicknesses in the manner according to the invention. This is not only the case with the inner strands of the cords, but also with the outer strands, which was not obvious in the run-up to the tests.

The resulting effect of reduced abrasion seems to be based on an interaction that arises from the fact that the thickened coating can act both as a “smear layer” and as a “sacrificial layer”. In any case, with zinc coatings, the occurrence of brown friction rust is avoided or significantly delayed, advantageously and particularly pronounced when the cords are formed from several strands, with an inner central strand being surrounded by several external strands.

An advantageous development consists in that the filament of the inner central strand which forms the strand core has a thicker coating than the filaments forming the strand cores of the outer strands. Here, too, tests have shown that abrasion can be further reduced by such a measure and the durability or service life of the elevator belt is further increased.

Another advantageous embodiment consists in that the coating of the filaments forming the stranded cores is at least 10% thicker than the coating of the filaments surrounding the stranded cores, preferably more than 30% thicker. On the one hand, such differences are process-technically feasible. On the other hand, a limitation with regard to economic considerations is guaranteed.

The same applies to a further advantageous embodiment, which consists in that the coating of the filaments forming the stranded cores is on average thicker than 2 μm. The indication “on average thicker” seems to be only superficially imprecise, but is necessary in practice in order to take into account the special features of different coating processes in which slight deviations over the entire surface or length of the filaments are possible and inherent in the process. For example, at the zinc coating of steel filaments a series of measurements over the length of a filament, with which an average value is then determined. This takes into account the fact that when coating such elements, on the one hand, an optimization is sought with regard to the smallest possible amount of coating material, but on the other hand, the minimum layer thickness should not be fallen below.

For a large part of the applications there is a further advantageous embodiment that the cords are designed as steel cords and the coating is a zinc layer. In this way one obtains relatively easy to manufacture and inexpensive cord materials which meet the requirements for elevator belts in the best possible way.

Another advantageous embodiment for such a cord construction is that the zinc layer contains further alloy components, preferably aluminum (Al). This increases the corrosion resistance and further reduces the abrasion. The same applies to an advantageous embodiment in which the elevator belt has cords with filaments in which an iron-zinc alloy is formed between the zinc layer and the filament surface.

Another advantageous embodiment of an elevator belt is that the tension or strength members are designed as steel cords in the form of a 7x7 construction. The inner central strand has a filament forming the strand core with a zinc coating of at least 1.5 µm or in a second variant at least 2.5 µm, as well as six filaments surrounding the strand core with a zinc coating of at least 1.0 µm or in a second variant at least 2 , 0 µm. The six outer strands each have a filament forming the strand core with a zinc coating of at least 1 µm or in a second variant at least 2.0 µm and six filaments surrounding the strand core with a zinc coating of at least 0.5 µm or in a second variant at least 1.0 µm .

Which of the two variants is better for the respective application depends, among other things, on the length weight of the tension members / cords, i.e. the length weight of the elevator belt, as provided for in the design of the elevator construction.

In addition to other possible and typical designs, the second variant / training also serves as an exemplary embodiment, as shown in 1 is shown.

The 1 shows a cord or tension member 1 an elevator belt. The tension member is a steel cord in the form of a 7x7 construction, i.e. the cord or tension member 1 seven strands each L1 to L7 with seven filaments F1 to F7 each, namely a central strand L1 and six strands surrounding this central strand on the outside L2 to L7 . Each strand then again has a filament F1 serving as a strand core, the so-called “king filament”, which is surrounded by six further filaments F2 to F7.

For a better overview, there are those for the central, inner strand L1 Corresponding filaments are provided with a further index “i” so that the inner strand carries the filaments Fi1 to Fi7 having. The filaments of the strands arranged on the circumference are corresponding L2 to L7 provided with a further index "a" so that the outer strands are the filaments Fa1 to Fa7 exhibit.

The inner central strand L1 has a filament forming the stranded core Fi1 with a zinc coating of at least 2.5 µm, as well as six filaments surrounding the stranded core Fi2 to Fi7 with a zinc coating of at least 2.0 µm. The six outer strands L2 to L7 each have a stranded wire core Fa1 forming filaments with a zinc coating of at least 2.0 µm as well as six filaments surrounding the respective strand core Fa2 to Fa7 with a zinc coating of at least 1.0 µm. In this case, the zinc coating corresponds to the respective inner core Fa1 (the outer strands L2 to L7 ) the zinc coating of the outer filaments Fi2 to Fi7 the inner strand L1 .

Of course, other common cord constructions can also be designed in the manner according to the invention, for example constructions of the 7x19, 19 + 8x7 or similar types.

List of reference symbols

1

Cord

Fa1

Filament / king filament (outer strand)

Fa2

Filament (outer strand)

Fa3

Filament (outer strand)

Fa4

Filament (outer strand)

Fa5

Filament (outer strand)

Fa6

Filament (outer strand)

Fa7

Filament (outer strand)

L1

central strand

L2

Outer strand

L3

Outer strand

L4

Outer strand

L5

Outer strand

L6

Outer strand

L7

Outer strand

Fi1

Filament / king filament (central strand)

Fi2

Filament (central strand)

Fi3

Filament (central strand)

Fi4

Filament (central strand)

Fi5

Filament (central strand)

Fi6

Filament (central strand)

Fi7

Filament (central strand)

Claims (10)

Elevator belt made of elastomeric material, which has embedded tensile or strength members running in the longitudinal direction of the belt, which are designed in the form of cords from one or more strands (L1-L7), the strands being made up of filaments provided with a coating, which are around a filament serving as a stranded core (Fi1, Fa1) is arranged, preferably laid, characterized in that the filament forming the stranded core is provided with a thicker coating than the filaments (Fi2-Fi7; Fa2-Fa7) surrounding the stranded core. Elevator belt after Claim 1 , in which the cords are formed from several strands, an inner central strand (L1) being surrounded by several external strands (L2-L7). Elevator belt after Claim 2 , in which the filament (Fi1) forming the strand core of the inner central strand (L1) has a thicker coating than the filaments (Fa1) forming the strand cores of the outer strands (L2-L7). Elevator belt according to one of the Claims 1 to 3 , in which the coating of the filaments (Fi1, Fa1) forming the stranded cores is at least 10% thicker than the coating of the filaments surrounding the stranded cores (Fi2-Fi7; Fa2-Fa7), preferably more than 30% thicker. Elevator belt after Claim 4 , in which the coating of the filaments forming the stranded cores is on average thicker than 2 µm. Elevator belt according to one of the Claims 1 to 5 , in which the cords are designed as steel cords and the coating is a zinc layer. Elevator belt after Claim 6 , in which the zinc layer contains further alloy components, preferably aluminum (Al). Elevator belt after Claim 6 or 7th , in which an iron-zinc alloy is formed between the zinc layer and the filament surface. Elevator belt according to one of the Claims 6 to 8th , in which the tension or strength members are designed as steel cords in the form of a 7x7 construction, the inner central strand having a filament forming the strand core with a zinc coating of at least 1.5 µm and six filaments surrounding the strand core with a zinc coating of at least 1 µm while the six outer strands each have a filament forming the strand core with a zinc coating of at least 1 µm and six filaments surrounding the strand core with a zinc coating of at least 0.5 µm. Elevator belt according to one of the Claims 6 to 8th , in which the tension or strength members are designed as steel cords in the form of a 7x7 construction, the inner central strand having a filament forming the strand core with a zinc coating of at least 2.5 µm and six filaments surrounding the strand core with a zinc coating of at least 2, 0 µm, while the six outer strands each have a filament forming the strand core with a zinc coating of at least 2.0 µm and six filaments surrounding the strand core with a zinc coating of at least 1.0 µm.

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