EP1930497B1 - Synthetic fibre rope, method for monitoring the service life of a synthetic fibre rope and lift with a synthetic fibre rope - Google Patents

Description

The invention relates to a synthetic fiber rope consisting of strands arranged in at least one strand layer, wherein at least one strand of at least one strand layer comprises indicator fibers or at least one indicator yarn for monitoring the life of the rope according to the definition of the independent patent claims.

From the registration EP 1 371 597 A1 is known as a suspension for lifts used, sheathed rope known. The rope has inner layers of strands and outer layers of strands, wherein a strand layer consists of several stranded strands and the stranding direction of the inner strand layers is opposite to the stranding direction of the outer strand layer. The tensile strength of the inner strand layers is higher than the tensile strength of the outer strand layer. Each strand is constructed of stranded and impregnated aramid fibers. The service life of the outer strand layer is smaller than the service life of the inner strand layers. To monitor the rope individual strands of the outer strand layer are provided with electrically conductive wires, each two adjacent strands are provided with electrically conductive wires that rub against each other and thus detect the expiration of the rope life or the end of the Seillebensdauer in a timely manner.

From the registration EP 0 731 209 A1 is one as Tragmittel for lifts used, sheathed rope has become known. The cable has inner layers of strands and outer layers of strands, wherein a strand layer consists of several stranded strands and the stranding direction of the inner strand layers is in the same direction as the stranding direction of the outer strand layer. Each strand is constructed of stranded and impregnated aramid fibers. To monitor the rope life or the Ablegereife the synthetic fiber rope each a strand of a strand layer is provided with electrically conductive carbon fibers. During operation, in any case, the carbon fibers either tear or break rather than the load-bearing aramid fibers of the strand either due to excessive strains or too large a number of bending changes. With the help of a voltage source, the number of cracked carbon fibers can be determined. In order to ensure a residual capacity of the synthetic fiber rope, only a certain percentage of the carbon fibers may fail. Then the elevator is automatically driven to a predetermined stop and turned off.

The invention aims to remedy this situation. The invention, as characterized in claim 1, solves the problem of providing a synthetic fiber rope with increased sensitivity for monitoring the life of the rope.

Advantageous developments of the invention are specified in the dependent claims.

The monitoring of rope life is a fundamental problem of all synthetic fiber ropes, especially those that are surrounded by a jacket.

According to the current state of the art, the Carbon fibers are selected according to the load requirements in the rope and arranged. A disadvantage of this method may be that the parameters to be conditioned can not be optimally matched to each other and the suspension means must be replaced too early to be far enough from the critical state. In elevator construction, synthetic fiber ropes serving as suspension means can be used up to 60% or 80% of the residual breaking force, based on the normal breaking force. The more precisely this point can be reached, the more economically can suspension elements be used.

Depending on the type, field of application and safety requirements of the synthetic fiber rope application, there are increased demands on the monitoring sensitivity of the indicator strands of the synthetic fiber rope. Correct response and replicability depending on the requirements are advantageous properties of the inventive synthetic fiber rope. As is known, synthetic fiber cables serving as lifting means for elevators are permanently electrically monitored by means of yarns of carbon fibers integrated in the cable strands. The advantage here is that the synthetic fiber ropes over its entire length including non-visible areas, such as the areas in the cable locks, are monitored. The synthetic fiber ropes detect the abrasive wear within the rope and reliably detect damage caused by external forces and give the elevator user a maximum level of security through the permanent connection to the elevator control, which can respond quickly and uncompromisingly when needed.

The requirements for a modern suspension element monitoring have increased compared to earlier. So that the synthetic rope must be brought up to the limit of failure and thus the economic potential of the new support means can be used more fully, or the user can set according to his needs sensitivity of the cable ripening detection, the strands with indicator fibers must be even better adjustable in their response, the indicator fibers Depending on the number of bending cycles to be achieved and residual breaking force, the strands lose their electrical conductivity with a high probability and thus detect cable wear.

An indicator fiber may be any material that is conductive in any form, such as fiber-optic fibers or metallic coated engineering fibers, carbon fibers, etc. that are electrically conductive, with the fibers rubbing sooner on direct wear contact the carrying fibers.

For permanent monitoring, the conductive indicator fibers are contacted at the end of the rope and connected to devices. At one end of the rope the indicator fibers are connected to a signal transmitter and at the other end of the rope, the indicator fibers are connected to a signal receiver. The transmission signal is measured by means of the signal receiver and evaluated on the basis of the measured or the missing signal, the state of the indicator fibers. EP 0 731 209 A1 shows an example of an indicator fiber monitoring by means of electrical signals.

A synthetic fiber rope consists of several stranded strands arranged in different layers, wherein each strand consists of stranded yarns, wherein a yarn consists of, for example, 1000 synthetic fibers. A raw yarn consists either of unidirectional synthetic fibers or has a protective rotation of, for example, 15 revolutions per meter for better processability already at the factory. As a rule "fiber" is used as a length-independent generic term for all textile fibers. "Filament" is the name for textile fibers of very large or practically endless length in the manufacture of man-made fibers. The stranding direction of the yarns in the strands is provided so that the single fiber is advantageously aligned in the pulling direction of the rope or in the cable longitudinal axis. The synthetic fiber rope may be composed of chemical fibers such as aramid fibers or related fibers, polyethylene fibers, polyester fibers and glass fibers, etc. The synthetic fiber rope may consist of one or two or three or more than three strand layers. At least one strand of at least one strand layer has indicator fibers or at least one indicator yarn for monitoring the life of the rope.

According to the invention, the plastic surrounding the strand provided with at least one indicator fiber or an indicator yarn also called matrix has a lower abrasion resistance than the matrix of the remaining strands.

In the case of the synthetic fiber rope according to the invention, the matrix material or the resin of the strands surrounding the strands may comprise indicator fibers or indicator yarns of a softer plastic (for example Shore hardness range A) than the matrix materials (for example Shore hardness range D) of the adjacent or remaining strands, as a result of which this strand is opposite to one another Strand without indicator fibers or indicator yarn a lower resistance to Abrasion has. As an alternative to the softer plastic, the matrix material may be interspersed with a plasticizer. For this purpose, known plasticizers can be used. Due to the poorer abrasion behavior of the strands with indicator fibers an early onset wear and thus earlier failure of the indicator fibers in the strands is provoked during the bending by the relative movement to the adjacent strands. The strand with indicator fibers or indicator yarn acts as a predetermined breaking point. The stranded wire with indicator fibers or indicator yarn is referred to below as the indicator strand. Depending on the type and amount of the selected plasticizer, the wear increase can be controlled.

Phthalates and adipates are typical softeners that soften the strand whose transverse stiffness is lower and the resistance to abrasion is reduced. By choosing a weight ratio of 1% to 30% on the matrix of the indicator strand, the matrix can be made "softer" than the neighboring strands, with increasing amount of plasticizer, the abrasion behavior deteriorates depending on the degree of softness.

Furthermore, the matrix material of the adjacent strand or other strands (strand without indicator fibers or indicator yarn) which is identical to the matrix material of the indicator strand can be mixed with an additive which reduces the friction with respect to the indicator strand. As additives, for example, waxes or small amounts of Teflon can be added. (1 to 3% wax or 5 to 15% Teflon powder, based on the solids content of the matrix without fiber content).

Furthermore, this can be done with the matrix material of the neighboring strand identical matrix material of the indicator strand during manufacture are treated so that the plastic matrix degraded until the hardness and the wear resistance decreases. This is achieved by a temperature treatment of the indicator strand at a temperature greater than 230 ° and a treatment time of more than 20 s. Due to the temperature, the long molecular chains required for the material properties separate so much that the molecules no longer completely recombine on cooling. To support this process, the stranded matrix can be fed with water molecules that prevent complete recombination of the molecular chains. Alternatively, other molecules are conceivable that impair or prevent recombination. There is an initial degradation of the matrix, which leads to a significantly lower abrasion resistance and thus provokes a failure of the indicator fibers or the indicator yarn. The abrasion protection is deliberately deteriorated.

The indicator fibers or the indicator yarn is located in the vicinity of the Litzenoberfläche and makes the helical structure of the synthetic fibers or artificial fiber yarns with. Because of the softer stranded matrix, the indicator fibers or the indicator yarn are rubbed through. Thus, the permanent monitoring of the load-bearing strand is interrupted and detected as wear before the other supporting strands were affected. This ensures that the indicator strands have different performance not only because of the different elongation at break, but also because of the different hardness of the matrix, a reliable failure probability is generated. (The elongation at break is stretching until a fiber, yarn or strand breaks).

Furthermore, it is possible to position the indicator strands in a multilayer synthetic fiber rope in such a way that the load bearing is higher in relation to the adjacent strands. For example, take the case of a synthetic fiber rope with three strand layers, the two inner concentric Litzenlagen a higher load share, because although the lay length compared to the outermost layer is constant, the impact angle to the center of the synthetic fiber rope is getting smaller. The strands are significantly steeper in the rope network, whereby the strands are shorter or longer depending on the situation. Due to the geometric limitation, the innermost strands are the shortest and therefore have the higher percentage of support. It is therefore advisable to arrange further indicator fibers or indicator yarns in individual strands of the two inner strand layers. Here, in a three-ply rope, the middle strand layer is to be preferred because this layer is subjected to increased stress due to the different winding radii and thus different bending speeds.

Furthermore, a synthetic fiber with very good dynamic bending strength can be used for the strand construction of the strand without indicator fibers. For the indicator yarn of the indicator strand, the indicator fibers (for example, carbon fibers) may be combined with synthetic fibers whose dynamic bending repellency is inferior to that of the other synthetic fibers of the indicator strand or that of the synthetic fibers of the strand without indicator fibers. The superior synthetic fibers exist for the use of current co-polymer based suspending agents, for example copoly-terephthalamide, among these Conditions of working inferior fibers may be poly-p-phenylene terephthalamide. (The dynamic bending capacity is the bending capacity under changing loads).

Furthermore, for the construction of the indicator yarn, the indicator fibers (for example carbon fibers) can be combined with synthetic fibers which have a higher modulus of elasticity compared to the other synthetic fibers of the indicator strand or to the synthetic fibers of the strand without indicator yarn. For the synthetic fibers which are combined with the indicator yarns in the indicator strands, for example, Twaron fibers having an E-modulus of 100,000 to 120,000 N / mm ² can be used. The remaining fibers of the non-indicator strands may for example consist of techno fibers with 76'000 N / mm ² .

The above measures to monitor the life of the rope can also be combined. For example, the resistance to abrasion by changing the stranded matrix can be provided and at the same time the indicator yarn consist of indicator fibers and synthetic fibers which are inferior in stress to the other synthetic fibers.

Claims (10)

1. Synthetic fibre cable consisting of strands arranged in at least one strand layer, wherein each strand consists of stranded yarns and the yarns consist of synthetic fibres, wherein at least one strand of at least one strand layer comprises indicator fibres or at least one indicator strand for monitoring of the cable service life of the synthetic fibre cable, characterised in that the at least one strand with indicator fibres or with at least one indicator yam has a lower capability of resistance to abrasion by comparison with the remaining strands of the synthetic fibre cable in that the matrix of the at least one strand with indicator fibres or with at least one indicator yam has a lower abrasion resistance than the matrix of the remaining strands of the synthetic fibre cable.
2. Synthetic fibre cable according to claim 1, characterised in that the matrix of the at least one strand with indicator fibres or with at least one indicator yam is saturated by softener.
3. Synthetic fibre cable according to claim 1, characterised in that the matrix of the at least one strand with indicator fibres or with at least one indicator yam is designed with a lower Shore hardness than the matrix of the adjacent or remaining strands of the synthetic fibre cable.
4. Synthetic fibre cable according to claim 1, characterised in that the matrix of the at least one strand with indicator fibres or with at least one indicator yarn is degraded by means of heat treatment and/or by means the addition of molecules.
5. Synthetic fibre cable according to any one of the preceding claims, characterised in that the matrix of the remaining strands of the synthetic fibre cable is mixed with an additive which reduces friction relative to the at least one strand with indicator fibres or with at least one indicator yam.
6. Synthetic fibre cable according to any one of the preceding claims, characterised in that the at least one strand with indicator fibres or with at least one indicator yam is so positioned that the load-bearing capability is higher by comparison with the adjacent strands of the synthetic fibre cable.
7. Method of monitoring the cable service life of a synthetic fibre cable according to any one of claims 1 to 6, characterised in that the strands of the synthetic fibre cable are permanently monitored by means of the indicator fibres.
8. Method according to claim 7, characterised in that for monitoring of the indicator fibres the indicator fibres are connected at one cable end with a signal transmitter and at the other cable end with a signal receiver and that a transmitted signal of the signal transmitter is measured by means of the signal receiver and the state of the indicator fibres is evaluated on the basis of the measured or absent signal.
9. Method according to claim 8, characterised in that the monitoring of the indicator fibres is carried out by means of optical or electrical signals.
10. Lift with synthetic fibre cable according to any one of claims 1 to 6.