HK1209164B - Rope for an elevator, elevator and method - Google Patents

Description

Rope for an elevator, elevator and method

Technical Field

The invention relates to a rope of a hoisting device, in particular of an elevator, in particular for transporting passengers and/or goods.

Background

Elevators typically have ropes for suspending an elevator car. Often they also comprise a counterweight suspended by the same ropes as the elevator car. The rope is provided with one or more load bearing members which bear the weight of the load suspended by the rope. The cross-section of the cord is circular or ribbon-like. A round cord usually comprises only one load bearing member, whereas a belt-like cord usually comprises one wide load bearing member, or several load bearing members spaced apart in the width direction of the cord. The load bearing member is conventionally a bundle of steel cords twisted together and there is a load bearing member made of a fibre-reinforced composite material. Document WO2009090299a1 discloses a recently developed structure for such a load-bearing member.

The elevator rope can be damaged during its use for various reasons. Damage is generally caused by normal wear, but unpredictable events can also occur in the elevator environment. The problem is that often initially very small damages easily propagate and eventually the rope needs to be replaced. In order to determine a safe service life for the rope, it is measured, for example, at a certain service time or at a certain amount of use, which is selected such that dangerous damage is unlikely to form over the service life of the rope. A disadvantage of any ropes according to the prior art is that eventually they need to be replaced. In particular, replacement of the ropes earlier than planned incurs some costs, whereby this should be avoided. A rope having a load-bearing part made of a fibre-reinforced composite material has a long service life, but the rope is expensive, which may be preferred if the service life can be even longer.

Disclosure of Invention

The object of the invention is to introduce a rope for a hoisting device, which is improved with respect to rope damage control, particularly for the rope of an elevator, because the safety and service life of the rope are particularly important in an elevator. The object of the invention is also to introduce an elevator and a method which are improved with respect to rope damage control. In particular, the object of the present invention is to solve the drawbacks of the previously described known solutions and the problems discussed later in the description of the invention. In particular, the object of the invention is to prolong the durability of the elevator rope. In particular, some embodiments are shown which facilitate postponing the replacement of the used ropes, possibly even completely avoiding replacing the used ropes earlier than planned/expected. In particular, embodiments are shown that facilitate rope condition monitoring and maintenance.

A new rope for an elevator is presented, said elevator comprising at least one continuous load-bearing member extending in the longitudinal direction of the rope over the entire length of the rope, which load-bearing member is made of a composite material comprising reinforcing fibers embedded in said polymer matrix. The composite material comprises capsules embedded in the polymer matrix, which capsules store the monomeric substance in fluid form. This makes it possible that cracks formed in the rope during use of the rope are constantly repaired by a self-repair process. During this self-healing process, monomer escapes from the capsule into the fracture where it polymerizes. Thus, the propagation of the crack from micro-scale to macro-scale may slow down or even stop completely. Thereby, the service life/durability of the rope can be increased. Each of the bladders includes a wall defining a closed hollow interior space in which the monomer mass is stored, each bladder leak-tightly sealing the monomer mass when the bladder wall is intact.

In a further improved embodiment, the capsules are substantially uniformly distributed in the composite material. Thus, the self-healing capability is achieved uniformly in all portions of the load bearing member. Also, the load bearing capacity of the load bearing member is thereby minimally affected by the capsule.

In a further improved embodiment, the composite material comprises an optical indicator substance in fluid form stored in capsules embedded in said polymer matrix, said optical indicator substance being substantially different in its optical properties from those of the matrix and/or the reinforcing fibers. The indicator substance in fluid form enables it to flow out of the capsules in which it is stored and to diffuse in the carrier member if cracks formed in the carrier member reach and rupture the capsules. The optical properties are adapted to indicate where the substance has been diffused within the carrier member. Thus, the position of the crack can be found by performing optical analysis. The capsule storing the optical indicator substance is preferably the same capsule as the capsule storing the single substance. The indicator substance and the monomer substance are in this case preferably mixed with each other, and the mixture of the optical indicator substance and the monomer substance differs substantially in its optical properties from the optical properties of the matrix and/or the reinforcing fibers.

In a further improved embodiment, the optical indicator substance differs substantially in one or more of its fluorescence, colour and contrast from those of the same material of the matrix and/or reinforcing fibres, at least when it has escaped from the ruptured capsules and diffused through the carrier member in the slits of the carrier member. The optical indicator substance is adapted to optically indicate where the material has diffused from the capsule, thereby also indicating the shape and size of the crack.

In a further improved embodiment, the optical indicator substance is fluorescent and sensitive to ultraviolet radiation. Thereby, even very small cracks can be identified.

In a further improved embodiment, the at least one load-bearing member is embedded in a transparent coating forming a surface of the rope, through which transparent coating the surface of the at least one load-bearing member is visible. Thereby, a surface of at least one load bearing member is visible through the transparent coating, whereby an optical (e.g. visible) inspection of the load bearing members of the rope is possible. The advantage is that the results of the self-healing process can be confirmed by eye.

In a further improved embodiment, each capsule storing the optical indicator substance comprises a wall delimiting a closed hollow inner space in which the optical indicator substance is stored.

In a further improved embodiment, the capsules are in the form of hollow fibers, storing the monomer material in the hollow interior space.

In a further improved embodiment, the composite material further comprises a catalyst substance for triggering and/or accelerating the polymerization reaction of the monomer substance when in contact therewith. The catalyst material is within a polymer matrix material. Thereby, the monomer species may contact the fracture by flowing into it. With regard to the constitution of the catalyst substance, it is preferable that it comprises ruthenium. Typically, it may include a transition metal carbene complex (catalyst by Grubbs).

In a further improved embodiment, the wall of the capsule comprises urea formaldehyde. This material is a very good working material for the walls of the capsules.

In a further improved embodiment, the capsule seals the indicator substance in a leak-tight manner when the walls of the capsule are intact.

In a further improved embodiment, the monomeric species comprises dicyclopentadiene (DCPD). Dicyclopentadiene is a very good working material in this context.

In a further improved embodiment the load bearing member is parallel to the longitudinal direction of the rope.

In a further improved embodiment, the reinforcing fibers are non-metallic fibers.

In a further improved embodiment, the reinforcing fibers are carbon fibers. Thereby, a lightweight rope with a very high load-bearing capacity and a very long service life can be achieved.

In a further improved embodiment, the polymer matrix comprises an epoxy resin.

In a further improved embodiment the reinforcing fibres are parallel to the longitudinal direction of the rope. Hereby, maximum rigidity for the load-bearing member as well as for the rope is achieved, whereby the rope is very suitable for use as a hoisting rope.

In a further improved embodiment the reinforcing fibres are continuous fibres extending substantially over the entire length of the rope. In a further improved embodiment, the capsules are in the form of hollow fibers and are oriented parallel to the reinforcing fibers.

In a further improved embodiment, the capsules in the form of hollow fibers are short fibers, in particular shorter than the reinforcing fibers. Thus, they can be easily and homogeneously manufactured and mixed in the matrix, as well as in the longer reinforcing fibers. In particular, there is no risk of the load-bearing capacity of the load-bearing member thereby.

In a further improved embodiment, the at least one load-bearing member is embedded in an elastomeric coating forming a surface of the rope.

In a further improved embodiment the rope comprises a plurality of said load bearing members.

In a further improved embodiment, the cord is ribbon-like.

In a further improved embodiment, the cord is belt-shaped, has a width substantially greater than the thickness in the transverse direction of the cord, and comprises a plurality of said load bearing members adjacent and spaced apart in the width direction of the cord.

A new elevator, such as a traction sheave elevator, is also presented, comprising an elevator car and roping comprising one or more ropes connected to the car, particularly to suspend the elevator car. The rope is as described above. Thereby, one or more of the advantages given above are achieved. In particular, an elevator is achieved with a long service life without replacing the ropes.

In a further improved embodiment said at least one load bearing member forms part of said electric circuit, the reinforcing fibres are electrically conductive fibres, such as carbon fibres, whereby the load bearing part is electrically conductive, and the elevator comprises rope condition monitoring means arranged to monitor one or more electrical characteristics of said electric circuit, preferably the electrical resistance of the electric circuit, the predetermined action being arranged to be initiated if a predetermined electrical characteristic, such as said electrical resistance, exceeds a predetermined limit value. The action to be initiated preferably comprises locating the position of the crack in the rope and checking the condition of the rope at the crack position. Thus, the success of the rupture and self-repair process can be noticed and verified. Such actions may alternatively or additionally comprise braking (striking) of the safety circuit of the elevator, whereby the safety of the elevator can be ensured until the state of the rope is checked.

A new method for condition monitoring of the ropes of an elevator is also presented, which elevator comprises an elevator car and ropes connected to the elevator car. The method comprises locating a position of a crack in the rope and inspecting the condition of the rope at the crack position. Preferably, the location of the crack in the rope is located by identifying a location having an optical property deviating (deviating), i.e. a location having an optical property deviating substantially from the optical property of the remaining rope.

In a further improved embodiment, the location of the crack in the rope is located by identifying a peak occurring in the optical indicator substance.

In a further improved embodiment, the position of the crack in the rope is located visually or by means of optical means.

In a further improved embodiment, the at least one carrier member forms part of an electrical circuit, one or more predetermined electrical characteristics of the electrical circuit, preferably the electrical resistance of the electrical circuit, are monitored, and the positioning and checking are performed if the predetermined electrical characteristics, such as the electrical resistance, exceed a predetermined limit value. Thereby, a change of the state of the rope can be noticed. Thereafter, the possible occurrence of cracking and the success of the subsequent self-healing process can be verified.

In a further improved embodiment, the optical indicator substance is fluorescent and sensitive to ultraviolet radiation by which the cord is irradiated for better visualization of the fluorescent substance. The location of the crack in the rope is located by identifying a location having an optical characteristic that deviates from the optical characteristic, i.e. a location having an optical characteristic that substantially deviates from the optical characteristic of the remaining rope. In this case, the position of the crack in the rope is located by identifying the peak occurring in the optical indicator substance, in particular by identifying the position at which the peak of the light emitted by the rope is located.

The elevator is preferably installed in a building, such as a tower. The elevator is preferably of the type whose car is arranged to serve two or more stopping floors. The car is preferably responsive to calls from the stopping floor and/or destination calls from within the car to serve the stopping floor and/or persons within the elevator car. Preferably, the car has an interior space adapted to receive one or more passengers, whereby safe transport of passengers is ensured.

Drawings

The invention will be described in more detail hereinafter, by way of example, with reference to the accompanying drawings, in which:

fig. 1 shows a cross-section of a rope according to a preferred embodiment;

fig. 2 shows the load bearing member of the rope shown in fig. 1 in three dimensions;

FIG. 3 illustrates a partial cross-section of the load bearing member shown in FIG. 2;

FIG. 4 shows a partial cross-section of the load bearing member shown in FIG. 2 when a fracture has occurred in the composite material;

fig. 5 presents an elevator according to a preferred embodiment;

fig. 6 and 7 show opposite ends of two carrier members, each of which forms part of the circuit being monitored.

Detailed Description

Fig. 1 shows a cross section of a rope 1 for a hoisting device, particularly for an elevator. The rope 1 comprises a continuous load-bearing member 2 extending over the length of the rope 1 in the longitudinal direction i of the rope 1. The load-bearing member 2 is made of a composite material comprising reinforcing fibers f embedded in a polymer matrix m. By this choice of material, the rope 1 can be formed to be light-weight and to be provided with good longitudinal rigidity and tensile strength. The carrier member 2 is thus shown in fig. 2. The cord 1 is preferably belt-like and thus has a width w substantially larger than its thickness t as seen in the transverse direction of the cord 1. Fig. 1 shows a rope 1 with a plurality of, in this case two, said load-bearing members 2 adjacent in the width direction of the rope 1. However, the rope 1 may alternatively be designed with only one of said load bearing members 2 or two or more load bearing members 2 adjacent in the width direction of the rope 1. In this embodiment the load bearing member 2 is embedded in an elastomer coating 9 forming the surface of the rope 1. Such a coating 9 protects the load-bearing member 2 and provides the rope with a high friction surface via which forces can be transmitted to the rope by means of a frictional engagement, for example by means of a traction sheave 21 as shown in fig. 5.

Fig. 3 shows an enlarged view of a cross section of a part of the carrier member 2 as seen in the longitudinal direction of the carrier member 2. The composite material comprises capsules 3 embedded in said polymer matrix m, which capsules 3 store the monomeric substance in fluid form. The monomer substance in fluid form makes it easy to diffuse if it leaks out of the capsule 3 in case the capsule 3 is ruptured due to cracks in the material in the carrier member 2. Fig. 4 shows a situation in which a small crack is formed in the carrier member 2. When small cracks form in the load bearing member 2, at least some of the capsules 3 embedded in the solid matrix m also eventually break. As a result, the monomer substance is free to drain out of the capsule 3 into the fracture. The substance leaking into the crack is a monomeric substance, whereby it adheres to the fractured walls, in particular to the polymer matrix m, forming a glue between the fractured opposite walls and filling the crack. Thus, the crack is prevented from expanding. In this way, the cracks can be stopped from expanding to a scale that is difficult to repair while they are still small. In order to ensure repair of the cracks in any position of the carrier member 2, the capsules 3 are substantially evenly distributed in the polymer matrix m.

The capsules are preferably such that each of them comprises a wall defining a closed hollow internal space in which the monomer is stored. The shape of the capsule is preferably elongate, the capsule most preferably being in the form of a hollow fibre storing monomer material in a hollow interior space. Thus, they are arranged to be interlaced between the reinforcing fibers f of the composite material. In particular, they may thus be parallel to the reinforcing fibers f. The elongated shape, in particular the fibrous shape, provides: the total volume of all capsules 3 can be easily distributed evenly along the length of the carrier part 2. Thus, the entire length of the load bearing member 2 can be effectively provided with self-healing capabilities without the excessive overall volume occupied by the capsules.

The monomeric material preferably or at least comprises dicyclopentadiene (DCPD). This monomeric substance is an example of a very well working material, but alternatively any other monomeric substance that has the same ability to polymerize when in contact with the substrate m or together with the catalyst may be used. The walls of the capsules may be of any suitable material, but preferably they comprise urea formaldehyde, which is well suited to storing the monomer material but is likely to rupture sufficiently easily when cracks in the composite material reach the capsules 3.

In order to ensure that the monomer substance remains reactive after the manufacture of the carrier member 2 and/or that the monomer substance only escapes the capsule when necessary, the capsule 3 seals the monomer substance in a leak-proof manner, i.e. when the walls of the capsule are intact.

In order to trigger and/or accelerate the polymerization reaction of the monomer species 3, the composite material further comprises a catalyst material 7 for triggering and/or accelerating the polymerization reaction of the monomer species when it is in contact with the catalyst material 7. The catalyst material 7 preferably comprises a metal carbene complex (Grubbs' catalyst). Preferably it comprises ruthenium. The catalyst material is homogeneously dispersed or embedded in the polymer matrix m, preferably in agglomerates. Fig. 3 and 4 show the catalyst 7. In case there is a need for: it is preferred to increase the effect of the catalyst 7 and then a denser and/or more uniform distribution of the catalyst 7 (compared to what is shown in figures 3 to 4). In that case, the catalyst may preferably be divided into smaller clusters than shown or alternatively dispersed homogeneously in the matrix m.

Fig. 4 shows the carrier member 2 when a crack 8 has been formed in the carrier member 2, and the monomer substance 5 has also leaked out of the ruptured capsules 3 and diffused through the carrier member 2 in the crack 8 of the carrier member 2. The monomer species have also reached the catalyst 7.

The reinforcing fibers f are preferably continuous fibers extending substantially over the entire length of the load-bearing member 2. Thus, the load-bearing capacity of the load-bearing member 2 is increased. The capsules 3, which in the preferred embodiment are in the form of hollow fibers, are substantially shorter fibers than the reinforcing fibers f. Thus, they can be manufactured and mixed in the matrix m and easily and homogeneously in the longer reinforcing fibers f.

The reinforcing fibers f are preferably non-metallic fibers, whereby a lightweight rope can be formed. In a preferred embodiment, the reinforcing fibers f are carbon fibers. Thus, a light weight rope 1 with a very high load bearing capacity can be achieved.

In a preferred embodiment, each of said load bearing members 2 is parallel to the longitudinal direction of the rope. Furthermore, the reinforcing fibers f are parallel to the longitudinal direction of the rope 1. Thus, the load-bearing properties of the rope, in particular the longitudinal stiffness and the tensile strength, are maximized. Furthermore, the capsules 3, which are in the form of hollow fibers, are oriented parallel to the reinforcing fibers f. Thus, they fit very well and are arranged (fit and seat) interwoven between the reinforcing fibers f of the composite material. The total amount of all capsules 3 can thus also be easily distributed evenly along the length of the carrier part 2.

In a preferred embodiment, the composite material comprises a capsule 3 embedded in said polymer matrix m, the capsule 3 storing an optical indicator substance 6, the optical indicator substance 6 being substantially different in its optical properties from the optical properties of the matrix m and/or the reinforcing fibers f. In a preferred embodiment, the capsule storing the optical indicator substance 6 is the same capsule as the capsule storing the monolithic substance 5. The indicator substance 6 and the monomer substance 5 are in this case mixed with one another and are thus shown as one. The mixture of optical indicator substance 6 and monomer substance 5 then differs in its optical properties substantially from the optical properties of the matrix m and/or the reinforcing fibers f. Although preferred for the purpose of optically indicating the crack, the presence of the optical indicator substance 6 is of course not necessary for the self-healing to be achieved. In case the indicator substance 6 is missing from the material stored by the capsule 3, the structure need not be changed from that shown in these figures. Also, of course one possible alternative is that the indicator substance 6 and the monomer substance 5 are stored in different capsules, in which case they would be completely separate fluid materials.

The purpose of the indicator substance 6 is to indicate where the monomeric substance 5 and the indicator substance 6 have diffused within the carrier member 2. The optical indicator substance 6 is also in fluid form in order to facilitate diffusion. The optical indicator substance 6 is substantially different in its optical properties from the matrix m and/or the reinforcing fibers f, it being identifiable from the material surrounding it. Thus, by performing optical analysis, the position of the crack can be found.

The optical indicator substance 6 is substantially different from those of the material of the matrix m and/or the reinforcing fibers f, in particular in one or more of its fluorescence, color and contrast, at least when it has leaked out of the ruptured capsules 3 and diffused in their slits through the carrier member 2. The indicator substance 6 can be given a specific colour by means of, for example, a pigment. The pigments may be organic or inorganic. Pigments may include, for example, titanium dioxide, zinc sulfide, iron oxide, cadmium compounds, chromium yellow or zinc aluminum flakes, copper or nickel.

To facilitate the finding of the crack 8 by using optical analysis, the load-bearing member 2 of the rope 1 is embedded in a transparent coating 9 forming the surface of the rope 1. The surface of at least one load bearing member 2 is visible through said transparent coating 9, whereby a visual inspection of the load bearing members 2 of the rope 1 is possible.

The rope 1 as described and illustrated is preferably a rope of an elevator. Fig. 5 presents an elevator according to a preferred embodiment. The elevator, which in this case is a traction sheave elevator, comprises an elevator car 30 and roping R comprising one or more ropes 1, which rope or ropes 1 are connected to the car 30, particularly to suspend the elevator car 30. The rope 1 is as described and illustrated elsewhere. The elevator is in this case provided with several stopping floors L served by the elevator car 1₀To L_n. The elevator comprises furthermore an elevator hoistway H in which the elevator car 1 and the counterweight 40 connected to the car 1 by means of the ropes 1 of the roping R are vertically movable. The elevator comprises a drive machine M which drives the elevator car 30 under the control of an elevator control system 23. The drive machine M comprises an electric motor 2 and a traction sheave 21 engaging the elevator ropes 1 passing around it, preferably frictionally. Thus, the driving force can be transmitted from the motor to the car via the traction sheave 21 and the ropes 11。

The elevator is preferably provided with a condition monitoring device 50 for monitoring the condition of the rope 1. Fig. 5 to 7 show the structure of the condition monitoring device 30. In this structure the condition monitoring device 50 is connected to the carrier members 2, each forming part of an electrical circuit, and the reinforcing fibres f are electrically conductive fibres, preferably carbon fibres, whereby the carrier member 2 is electrically conductive. In this configuration, the condition monitoring means 50 is arranged to monitor one or more electrical characteristics of the circuit, most preferably the resistance of the circuit. A predetermined change of the electrical characteristic, for example the resistance, is thus interpreted as an indication of a lowered condition of the rope 1. In particular, the increase in electrical resistance may be the result of a rupture of the load-bearing member 2. Thus, based on the monitored change in the electrical properties of the load bearing member 2, it can be inferred whether a rupture has occurred. The predetermined action is arranged to be initiated if a predetermined electrical characteristic, e.g. the electrical resistance, which changes in a predetermined manner, for example exceeds a predetermined limit value. To perform the monitoring action and to determine whether the limit value has been exceeded, and to initiate the predetermined action, the monitoring means comprises suitable means, such as a processor and a memory, but any other suitable means may be used. The action to be initiated preferably comprises locating the position of the crack in the rope 1 and checking the condition of the rope 1 at the crack position. Thus, the success of the rupture and self-repair process can be verified. Such action may alternatively or additionally include braking of the safety circuit 52 of the elevator. As shown in fig. 7, the elevator preferably includes a safety circuit 52. The condition monitoring device 50 is in this case arranged to brake the safety circuit 52 of the elevator if a predetermined electrical characteristic, such as the resistance, exceeds a predetermined limit value. The opening of the safety circuit 52 is arranged to cause braking of the rotation of the traction sheave 21 and/or to stop rotating the traction sheave 21. Thus, in case the electrical characteristics of the load bearing member change in a predetermined manner, the elevator is brought into a safe state by immediately stopping the movement of the car. The safety circuit (also called safety chain) is a known feature of elevators and it is therefore not described in more detail here. The condition monitoring device 50 is in a preferred embodiment arranged to control a safety relay 51, which is a safety switch controllable to open a safety circuit. There may be several of said limit values, in particular different limit values for each of said actions. Then, in particular, the limit value is selected such that the check is triggered more easily than the opening of the safety circuit 52. Thus, the self-healing process, as well as the inspection step, occurs while the condition of the rope 1 has not yet decreased to an unsafe level.

In a preferred embodiment of the method according to the invention the condition of the ropes 1 of the elevator is monitored. The rope 1 as well as the elevator are as described above and shown in fig. 1 to 7. The method comprises locating a crack in the rope 1 and checking the condition of the rope 1 at the crack location. Thus, the success of the rupture and self-healing process of the rope 1 can be verified. So that the decision relating to the following steps can be based on the verified condition of the rope 1. For example, the crack location 8 can thus be thoroughly inspected. For example, ultrasonography analysis may be performed to check whether the rope 1 needs to be replaced.

As mentioned above, the cord 1 is such that it comprises a load-bearing member 2 extending in the longitudinal direction of the cord 1 over the length of the cord 1, the load-bearing member 2 being made of a composite material comprising reinforcing fibers f embedded in a polymer matrix m, and the composite material comprising capsules 3 embedded in said polymer matrix m, the capsules storing a monomeric substance in fluid form.

To facilitate the identification of the position of the crack 8 in the cord 1, the composite material may comprise, as also explained above, a capsule embedded in said polymer matrix m, which in the case shown is the same capsule 3 as the capsule 3 storing the monolithic mass 5, storing the optical indicator mass 6 in fluid form. The optical indicator substance 6 is substantially different in its optical properties from those of the matrix and/or the reinforcing fibers, whereby it optically indicates the crack 8 when leaking out of its capsule 3. The substances 5 and 6 are stored in the same capsule causing them to flow into the same portion of the same slit 8, whereby the indicator substance 6 indicates where the monomer substance 5 has diffused in the composite material. In the method, the position of the crack in the rope 1 can be located by identifying a location having deviating optical properties. This is preferably performed by identifying peaks in the optical indicator substance 6. The position of the crack 8 in the rope 1 is then located visually or by means of optical means, such as a camera or a light source. The light source may be a light source having a wavelength suitable for causing the indicator substance to emit radiation if it is fluorescent. Preferably, the optical indicator substance is fluorescent and sensitive to ultrasonic radiation, i.e. emits visible light when irradiated in the ultraviolet region, in particular in the range between 400nm and 10 nm. Thereby, even small amounts of optical indicator substance are easily distinguishable, e.g. by visual or camera inspection. Thus, very small cracks 8 can be identified. Identifying the location of the crack 8 is important not only for determining whether the rope 1 can still be used but also for determining the cause of said crack 8 during the analysis of the operating condition of the rope 1. When the optical indicator substance is fluorescent and sensitive to ultraviolet radiation, and the cord is irradiated with ultraviolet radiation. The position of the crack 8 in the cord 1 is then located by identifying the position with deviating optical properties, in which case the position of the crack 8 in the cord 1 is located by identifying the peak occurring by the optical indicator substance, in particular by identifying the position of the peak of the light emitted by the cord 1.

Preferably, in the method one or more predetermined electrical characteristics of the electrical circuit, preferably the resistance of the electrical circuit, formed at least in part by the carrier member 2, are monitored, and the predetermined action is arranged to be initiated if the predetermined electrical characteristics of the electrical circuit, for example the resistance of the electrical circuit, change in a predetermined manner. Such actions preferably include that said positioning and checking is performed. In this embodiment, the reinforcing fibers f are electrically conductive fibers, preferably carbon fibers, which are most suitable for the purpose of conductivity and suitability in terms of functions for load bearing. By means of electrical condition monitoring, the condition of the rope 1 may be checked triggered by a change in the characteristics of the circuit. In particular, the positioning and checking are performed if the resistance of the circuit exceeds a predetermined limit value.

Such action may alternatively or additionally include braking of the safety circuit 52 of the elevator. The condition monitoring device 50 is in this case arranged to brake the safety circuit 52 of the elevator if a predetermined electrical characteristic, such as the resistance, changes in a predetermined manner, such as exceeds a predetermined limit value. The opening of the safety circuit 52 is arranged to cause braking of the rotation of the traction sheave 21 and/or stop the rotation of the traction sheave 21. Thus, in case the electrical characteristics of the load bearing member change in a predetermined manner, the elevator enters a safe state by immediately stopping the movement of the car. There may be several of said limit values, in particular different limit values for each of said actions. Then, in particular, the limit value is selected such that the check is triggered more easily than the opening of the safety circuit 52. Thus, a self-healing process, as well as an inspection step, occurs while the condition of the rope 1 has not yet decreased to an unsafe level.

The preferred composite structure of the load bearing member 2 is preferably as follows in more detail. The load-bearing member 2, and its fibres f, are parallel to the longitudinal direction of the rope and as untwisted as possible. The individual reinforcing fibers f are bonded into a uniform load-bearing member by the polymer matrix m. Thus, each load bearing member 2 is a solid elongated rod-like piece. The reinforcing fibres f are preferably long continuous fibres in the longitudinal direction of the rope 1, the fibres f preferably continuing over the entire length of the load-bearing member 2 and the rope 1. Preferably as many fibers f, most preferably substantially all fibers f of the load-bearing member 2 are oriented parallel to the rope as possible in an untwisted manner with respect to each other. The load-bearing member 2 is thus constructed so that its cross-section over the entire length of the rope is as uniform as possible. The reinforcing fibers f are preferably distributed as evenly as possible in the above-mentioned load-bearing member 2, so that the load-bearing member 2 is as homogeneous as possible in the transverse direction of the rope. The advantage of the shown structure is that the matrix m surrounding the reinforcing fibers f keeps the mutual positioning of the reinforcing fibers f substantially unchanged. It equalizes the distribution of forces exerted on the fibers by its slight elasticity, reducing the fiber-fiber contact and internal wear of the rope, thus improving the service life of the rope. The composite matrix m, in which the individual fibres f are distributed as uniformly as possible, is most preferably an epoxy resin, which has a good adhesion to the reinforcing fibres f and which is known to perform advantageously by means of carbon fibres. Alternatively, for example polyester or vinyl ester may be used, but alternatively any other suitable alternative material may be used. Fig. 3 and 4 show a partial cross-section of the load-bearing member as seen in the longitudinal direction of the rope, according to which cross-section the reinforcing fibers f of each load-bearing member 2 are preferably organized in a polymer matrix m. The other parts (not shown) of the carrier member 2 have a similar structure. As shown, the individual reinforcing fibers f are substantially uniformly distributed in the polymer matrix m, which surrounds the fibers bonded to the fibers f. The polymer matrix m fills the areas between the individual reinforcing fibers f and bonds substantially all of the reinforcing fibers f within the matrix m to each other as a homogeneous solid mass. Chemical bonding exists between individual reinforcing fibers f and the matrix m, preferably between all the reinforcing fibers f and the matrix m, one advantage of which is structural uniformity. In order to strengthen the chemical bond, there may, but need not, be an actual coating of fibers (e.g., a sizing, not shown) between the reinforcing fibers and the polymer matrix m. The polymer matrix m is preferably a hard non-elastomer. It may include additives for fine tuning the properties of the matrix as an addition to the base polymer. Reinforcing fibers f in the polymer matrix means here that the individual reinforcing fibers f are bonded to each other by the polymer matrix m, for example by impregnating them together in the fluid material of the polymer matrix m in the manufacturing stage. In this case, the interstices of the individual reinforcing fibers f, which are bonded to each other by the polymer matrix m, comprise the polymer of the matrix. In this way a large number of reinforcing fibers, which are bonded to each other in the longitudinal direction of the rope, are distributed in the polymer matrix. The reinforcing fibers f are preferably substantially evenly distributed in the polymer matrix so that the load-bearing member is as homogeneous as possible when seen in the direction of the cross-section of the rope. In other words, the fiber density in the cross section of the load-bearing member is therefore substantially unchanged. The reinforcing fibres f and the matrix m form a uniform load-bearing member in which no abrasive relative movements occur when the rope is bent. The individual reinforcing fibers f and the capsules 3 of the load-bearing member 2 are mainly surrounded by the polymer matrix m, but any fiber-fiber contact can occur, since it is difficult to control the position of the fibers relative to each other while the fibers are infusing with the polymer, on the other hand, a perfect elimination of any fiber-fiber contact is not necessary from the functional point of view of the invention. However, if it is desired to reduce any occurrence of them, the individual reinforcing fibers f may be pre-coated so that the polymer coating already surrounds the individual reinforcing fibers before they are bonded to each other. In the present invention, the individual reinforcing fibers of the load-bearing member may comprise material surrounding their polymer matrix such that the polymer matrix is next to the reinforcing fibers but instead a thin coating, such as a primer disposed on the surface of the reinforcing fibers during the manufacturing stage to improve chemical adhesion to the matrix material, may be located therebetween. The individual reinforcing fibers are evenly distributed in the load-bearing member 2 so that the interstices of the individual reinforcing fibers f are filled with the polymer of the matrix m. Most preferably a large part of the interstices, preferably substantially all of the interstices, of the individual reinforcing fibers f in the load-bearing member 2 are filled with the polymer of the matrix m. As mentioned above, the matrix m of the load bearing member 2 is most preferably hard in its material properties. The stiff matrix m helps to support the reinforcing fibers f, especially when the rope is bent, preventing knotting of the reinforcing fibers f of the bent rope, since the stiff material supports the fibers f. In particular, in order to reduce kinking and to facilitate a small bending radius of the rope, it is therefore preferred that the polymer matrix is hard and in particular non-elastomeric. The most preferred materials are epoxy, polyester, phenolics or vinyl esters. The polymer matrix is preferably so hard that its elastic modulus (E) is above 2GPa, most preferably above 2.2 GPa. In this case, the modulus of elasticity (E) is preferably in the range of 2.2-10GPa, most preferably in the range of 2.2-3.2 GPa. There are various commercially available alternatives for the substrate m that can provide the properties of these materials. Preferably more than 40% of the surface area of the cross-section of the load-bearing member 2 is of the above-mentioned reinforcing fibres, preferably such that 40-80% are of the above-mentioned reinforcing fibres f, more preferably such that 40-70% are of the above-mentioned reinforcing fibres, and the remaining larger proportion of the surface area is of the polymer matrix m, and the smaller proportion of the capsules 3. Most preferably, this is performed such that approximately 60% of the surface area is of the reinforcing fibres and approximately at least 35% is of the matrix material (preferably epoxy material). In this way, a good longitudinal rigidity for the load-bearing member 2 as well as a good electrical conductivity is achieved.

In this application the term "load bearing member 2" of the rope 1 refers to a member extending in the longitudinal direction of the rope 1 within the length of the rope 1. When the rope is pulled, e.g. suspended by the rope by means of a load, the tension resulting from said pulling can be transmitted within the load-bearing member 2 over its length, in particular from one end of the load-bearing member to its other end.

As mentioned, the number and shape of the load bearing members 2 may differ from that shown in fig. 1. As an alternative to the cross-section shown in fig. 1, the rope 1 may have the outer shape of the cross-section and/or the load-bearing member has a cross-sectional shape as shown in international patent application WO2009090299a 1.

As mentioned, to facilitate its diffusion, the optical indicator substance 6 is in fluid form. The fluid state may be provided to the optical indicator substance 6 in various forms. In a preferred embodiment, the indicator substance 6 and the monomer substance 5 are mixed with each other. The fluid state of the optical indicator substance 6 may then be provided at least in part by the monomeric substance 5.

It is to be understood that the foregoing description and drawings are only illustrative of the invention. It will be apparent to those skilled in the art that the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims (18)

1. A rope (1) for an elevator, comprising at least one continuous load-bearing member (2) extending in the longitudinal direction of the rope (1) over the entire length of the rope (1), which load-bearing member (2) is made of a composite material comprising reinforcing fibers (f) embedded in a polymer matrix (m), characterized in that said composite material comprises capsules (3) embedded in said polymer matrix (m), which capsules store a monomer substance in fluid form, each capsule (3) comprising walls delimiting a closed hollow inner space in which said monomer substance (5) is stored, each capsule (3) sealing said monomer substance (5) in leaktight manner when the walls of said capsule (3) are undamaged,

wherein the composite material comprises an optical indicator substance (6) in fluid form, stored in a capsule (3) which also stores capsules of a single substance (5) and is embedded in the polymer matrix (m), the optical indicator substance (6) being substantially different in its optical properties from those of the matrix (m) and/or reinforcing fibers (f).

2. A cord according to claim 1, whereby said optical indicator substance (6) differs substantially in one or more of its colour and contrast from the same ones in the material of said matrix (m) and/or reinforcing fibres (f).

3. Rope according to claim 1 or 2, wherein the at least one load-bearing member (2) is embedded in a transparent coating (9) forming the surface of the rope (1).

4. A cord according to claim 1 or 2, wherein each capsule (3) storing said optical indicator substance (6) comprises walls defining a closed hollow inner space, said optical indicator substance (6) being stored in said inner space.

5. A cord according to claim 1 or 2, whereby the capsules (3) are in the form of hollow fibres, storing said monomer substance (5) in a hollow inner space.

6. Rope according to claim 1 or 2, wherein the composite material further comprises a catalyst substance (7) for triggering and/or accelerating the polymerization reaction of the monomer substance (5) when in contact therewith.

7. Rope according to claim 4, wherein the walls of the capsule (3) comprise urea formaldehyde.

8. A rope according to claim 1 or 2, wherein said monomer substance (5) comprises dicyclopentadiene.

9. A rope according to claim 1 or 2, wherein the reinforcing fibres (f) are carbon fibres.

10. A rope according to claim 1 or 2, wherein the polymer matrix (m) comprises an epoxy resin.

11. A rope according to claim 1 or 2, wherein said reinforcing fibers (f) are continuous fibers extending substantially throughout the length of the rope (1).

12. A cord according to claim 1 or 2, whereby said reinforcing fibers (f) are parallel to the longitudinal direction of said cord (1), and the capsules (3) are in the form of hollow fibers and are oriented parallel to said reinforcing fibers (f).

13. A cord according to claim 1 or 2, whereby the capsules (3) are in the form of hollow fibers and are substantially shorter than said reinforcement fibers (f).

14. Elevator, comprising an elevator car (30) and roping (R) comprising one or more ropes (1) connected to the car (30), in particular to suspend the elevator car (30), characterized in that the rope (1) is as defined in any of the preceding claims.

15. Elevator according to the preceding claim, wherein the at least one load bearing member (2) forms part of an electric circuit, the reinforcing fibres (f) are electrically conductive fibres, whereby the load bearing member (2) is electrically conductive, the elevator comprising rope condition monitoring means (50) arranged to monitor one or more resistances of the electric circuit, and in that a predetermined action is arranged to be started if the resistance exceeds a predetermined limit value.

16. Method for condition monitoring of a rope (1) of an elevator, which elevator comprises an elevator car (30) and a rope (1) connected to the elevator car (30), which elevator is as defined in any one of the preceding claims, characterized in that the method comprises locating the position of a crack (8) in the rope (1) and checking the condition of the rope (1) at the position of the crack (8).

17. Method according to the preceding claim, wherein the composite material comprises an optical indicator substance (6) in fluid form, stored in a capsule (3), which capsule (3) also stores capsules of a single substance (5) and is embedded in the polymer matrix (m), the optical indicator substance (6) being substantially different in its optical properties from those of the matrix (m) and/or the reinforcing fibres (f), and in that the position of the crack (8) in the cord (1) is located by identifying a position having deviating optical properties.

18. Method according to any of the preceding claims 16 to 17, wherein said at least one carrier member (2) forms part of an electrical circuit, said reinforcing fibres (f) are electrically conductive fibres, whereby the carrier member (2) is electrically conductive, and said positioning and checking are performed if a predetermined resistance exceeds a predetermined limit value.