EP1428927B1 - Reinforced synthetic cable for lifts - Google Patents

Description

The invention relates to a Kunstoffsiel or belt as suspension means for elevators according to the definition of the claims.

• In seiner Funktion als Tragmittel trägt das Seil ein Betriebsgewicht des Aufzuges, bestehend aus dem Leergewicht der Kabine, der Nutzlast des Aufzuges, einem optionalen Gegengewicht und dem Eigengewicht des Seils. Das Seil wird dabei hauptsächlich durch Zugkräfte belastet. Bspw. hängen Kabine und Gegengewicht entlang der Schwerkraft am Tragmittel.
• In seiner Funktion als Treibmittel zum Bewegen der Kabine wird das Seil an eine Antriebsfläche der Treibscheibe gepresst. Das Seil wird dabei Press- und Biegebeanspruchungen ausgesetzt. Bspw. wird das Seil durch das Betriebsgewicht des Aufzuges an einen Umfang der Treibscheibe gepresst, so dass sich Seil und Treibscheibe im Reibschluss befinden.
• In seiner Funktion als Kraftübertragungsmittel überträgt die Treibscheibe die Kraft des Antriebes auf das Seil. Wichtige Parameter dabei sind ein materialspezifischer Reibwert zwischen Treibscheibe und Seil und ein konstruktionsspezifischer Umschlingungswinkel der Treibscheibe durch das Seil.

In an elevator, a traction sheave is often used to move a car. In such a traction sheave elevator traction sheave and cabin, for example. Connected to each other via a rope. A drive sets the traction sheave in rotary motion. By a frictional engagement between traction sheave and rope, the rotational movement of the traction sheave is converted into a movement of the cabin. The rope serves as a combined carrier or propellant, while the traction sheave serves as a force transmission means:

• In its function as a means of suspension, the cable carries an operating weight of the elevator, consisting of the unladen weight of the car, the payload of the elevator, an optional counterweight and the weight of the rope. The rope is mainly loaded by tensile forces. For example. Cab and counterweight hang along gravity on suspension element.
• In its function as a propellant for moving the cabin, the rope is pressed against a driving surface of the traction sheave. The rope is subjected to pressing and bending stresses. For example. The rope is pressed by the operating weight of the elevator to a circumference of the traction sheave, so that the rope and traction sheave are in frictional engagement.
• In its function as a power transmission means, the traction sheave transmits the power of the drive to the rope. Important parameters here are a material-specific coefficient of friction between traction sheave and rope and a construction-specific wrap angle of the traction sheave through the rope.

To date, steel cables are used in elevator construction, which are connected to traction sheave, cab and counterweight. The use of steel cables, however, has some disadvantages. Due to the high weight of the steel cable the lifting height of an elevator system limits. Furthermore, the coefficient of friction between the metal traction sheave and the steel cable is so small that the coefficient of friction must be increased by various measures such as special groove shapes or special groove feeds in the traction sheave or by increasing the wrap angle. In addition, the steel cable between the drive and the cabin acts as a sound bridge, which means a reduction in ride comfort. In order to reduce these undesirable effects, complex constructive measures are required. In addition, steel cables endure a lower number of bending cycles compared to plastic cables, are subject to corrosion and must be regularly serviced. WO 84/02354 discloses the reinforcement of steel cables by a second phase in the ferrite matrix.

Plastic ropes are usually composed of a plurality of coiled and / or packed supporting strands as described in the patents US 4,887,422 . US 4 640 179 . US 4,624,097 . US 4,202,164 . US 4 022 010 and EP 0 252 830 can be seen.

The patents US 5 566 786 and US 2002/0000347 disclose the use of a plastic cord as a lifting or propelling means for elevators which is connected to the traction sheave, cab and counterweight, the rope being made of supporting plastic strands. The strand layer is in US 5 566 786 covered by a jacket, whose task is to ensure the desired coefficient of friction to the traction sheave and to protect the strands against mechanical and chemical damage and UV rays. The load is carried exclusively by the strands.

Despite the considerable advantages over steel cables have in the patent US 5 566 786 described plastic ropes also on considerable restrictions, as well as in US 2002/0000347 is called.

Plastic ropes indicate a very good longitudinal strength, but which opposes poor radial strength. The plastic cables endure with difficulty the pressure exerted on their outer surface pressure, which can lead to an undesirable shortened life of the rope. Finally, the modulus of elasticity of today's plastic ropes is too small for lifts with greater lift heights: unwanted extensions of the rope occur and annoying vibrations of the set in motion elevator are noticed by the user, especially if the length of the rope has exceeded a certain limit.

Belts as a carrier or propellant are made US2002 / 0000347 known.

Object of the present invention is to propose a rope or belt as a support means or propellant for elevators of the type mentioned, which does not have the aforementioned disadvantages and by means of which the ride comfort and safety is increased. In particular, the following disadvantages are to be eliminated: the undesirable shortened life of the rope, the too small modulus of elasticity of the rope, the unwanted extensions of the rope and the annoying vibrations of the set in motion elevator.

This object is achieved by the invention according to the definition of the claims.
The advantages achieved by the invention are essentially to be seen in the fact that the strands of a multi-layered, sheathed rope or belt made of plastic, by the introduction of a second phase into which the fibers forming aramid reinforced and thus have a higher modulus of elasticity than that of the unreinforced strands.

By the classical definition of physical chemistry, by "phase" is meant a solid, liquid or gaseous body having homogeneous or at least without discontinuity varying physical and chemical properties, such as composition, elastic modulus, density, etc. (See P. Atkins, "Physical Chemistry", VCH, Weinheim, 1987, page 201 )

Formally, a Gibbs phase is defined as follows: A phase is a state of matter in which it is uniform throughout in its chemical composition and in its physical state.

This definition is consistent with the usual use of the word phase. Thereafter, a gas or gas mixture is a single phase; a crystal is a single phase; and two completely miscible liquids also form a single phase. Ice, too, is a single phase, even when broken up into small pieces. A slurry of ice and water, on the other hand, is a two-phase system, although it is difficult to locate the phase boundaries in this system.

An alloy of two metals is a two-phase system when the two metals are immiscible, but a single-phase system when they are miscible with each other.

The obtained reinforced rope indicates a higher modulus of elasticity in the longitudinal direction than that of the unreinforced rope. In addition, the obtained reinforced rope also has a higher modulus of elasticity, a higher strength and a higher breaking stress in the radial direction and a longer life than those of the rope without reinforcement out.

• Fig.1 ein Schnitt durch ein herkömmliches Kunststoffseil nach dem bisherigen Stand der Technik,
• Fig. 2 ein Zahnriemen
• Fig. 3 ein Poly-V-Riemen
• Fig. 4 ein Doppelseil (Twin-Rope)
• Fig.5 eine perspektivische Darstellung des herkömmlichen Kunststoffseils nach dem bisherigen Stand der Technik,
• Fig.6 ein Schnitt durch eine erfindungsgemäss verstärkte Faser,
• Fig.7 eine perspektivische Darstellung der erfindungsgemäss verstärkten Faser
• Fig.8 verschiedene geometrische Ausführungsformen der die Faser verstärkenden zweiten Phase.
• Fig.9 eine perspektivische Darstellung der erfindungsgemäss verstärkten Faser, falls die verstärkende zweite Phase aus langen orientierten Fasern besteht, die in der Matrix aus Aramid eingebaut werden und parallel zur Faser aus Aramid verlaufen.

In the following the invention with reference to exemplary embodiments according to the Figures 1-9 explained in detail. Hereby shows:

• Fig.1 a section through a conventional plastic rope according to the prior art,
• Fig. 2 a toothed belt
• Fig. 3 a poly V belt
• Fig. 4 a double rope (twin rope)
• Figure 5 a perspective view of the conventional plastic rope according to the prior art,
• Figure 6 a section through a fiber reinforced according to the invention,
• Figure 7 a perspective view of the invention reinforced fiber
• Figure 8 various geometric embodiments of the fiber amplifying second phase.
• Figure 9 a perspective view of the invention reinforced fiber, if the reinforcing second phase consists of long oriented fibers which are incorporated in the matrix of aramid and parallel to the fiber of aramid.

Fig.1 shows a section through a conventional plastic cord 1. A sheath 2 surrounds an outermost strand layer 3. The sheath 2 made of plastic, preferably polyurethane, increases the coefficient of friction of the rope 1 on a traction sheave. The outermost strand layer 3 must have such high binding forces to the casing 2 that it does not shift or form upsets due to the thrust forces occurring when the cable 1 is loaded. These binding forces are achieved by the plastic casing 2 is sprayed (extruded), so that all the spaces in the outer Litzenträger are filled and a large holding surface is formed (see EP 0672781 ). The strands 4 are turned or beaten from individual fibers 5 made of aramid. Each individual strand 4 is used to protect the fibers 5 with a Impregnating agent, eg polyurethane solution, treated. The flexural strength of the rope 1 depends on the proportion of polyurethane in each strand 4. The higher the proportion of the polyurethane, the higher the bending cycle performance. With increasing polyurethane content, however, the carrying capacity and the modulus of elasticity of the synthetic fiber rope 1 decreases with the same rope diameter. The proportion of polyurethane for impregnating the strands 4 can be, for example, between ten and sixty percent, depending on the desired bending change performance and transverse pressure sensitivity. Conveniently, the individual strands 4 can also be protected by a braided sheath made of polyester fibers.

In order to avoid wear of the strands on the traction sheave due to mutual friction, a friction-reducing intermediate sheath 7 is therefore provided between the outermost strand layer 3 and the inner strand layer 6. Thus, the wear is kept low at the outermost layer of strands 3 and inner strand layers 6, which perform the most relative movements in the bending of the rope on the traction sheave. Another means of preventing frictional wear on the strands 4 could be an elastic filling compound which bonds the strands 4 together without unduly reducing the flexibility of the rope 1.

A strand 4 is typically made as follows: 1000 fibers 5 with 12 μm diameter form 1 yarn. 11-12 yarns will then go to a strand 4.

Of course, the expert in the knowledge of the present invention can use the carrying rope without the use of a traction sheave. Also, the person skilled in a design as a double rope (Twin Rope) or as a belt as in Fig. 2-4 shown use. Fig. 2 shows a toothed belt, Fig. 3 shows a poly-V belt, Fig. 4 shows a double rope.

Unlike pure tethers driven hoist ropes must be very compact and firmly twisted or braided so that they do not deform on the traction sheave or start to spin as a result of your own or distraction. The gaps and voids between the individual layers of the strands 4 can therefore be filled by means of Füllitzen 9, which can act against other strands 4 supporting, to obtain a nearly circular Litzenlage 6 and to increase the degree of filling and around the peripheral sheath of the rope to round shape. These Füllitzen 9 are made of plastic, such as polyamide.

The aramid fibers 5 consisting of highly oriented molecular chains have a high tensile strength. However, in contrast to steel, the aramid fiber 5 has a rather low transverse strength because of its atomic structure. For this reason, no conventional steel cable locks for Seilendbefestigung of synthetic fiber ropes 1 can be used, since the clamping forces acting in these components greatly reduce the breaking load of the rope 1. A suitable Seilendverbindung for synthetic fiber ropes 1 is already by the PCT / CH94 / 00044 known.

Figure 5 shows a perspective view of the structure of the synthetic fiber rope according to the invention 1. The stranded fibers 4 made of aramid or beaten strands 4 are struck including the fillets 9 by a soul 10 layers left or right. Between an inner and the outer strand layer 3 of the friction-reducing intermediate jacket 7 is attached. The outermost strand layer 3 is covered by the casing 2. To determine a defined coefficient of friction, the surface 11 of the casing 2 can be structured. The object of the sheath 2 is to ensure the desired coefficient of friction to the traction sheave and protect the strands 4 from mechanical and chemical damage and UV rays. The load is carried exclusively by the strands 4. The rope 1 constructed from aramid fibers 5 has, with the same cross-section, a significantly higher load-bearing capacity compared with a steel cable and only one-fifth to one-sixth the specific weight. For the same load capacity, therefore, the diameter of a synthetic fiber rope 1 compared to a conventional steel cable can be reduced. By using the above materials, the rope 1 is completely protected against corrosion. Maintenance such as steel cables, eg to grease the ropes, is no longer necessary.

Figure 6 shows a schematic representation of a section through an inventive reinforced fiber 5 made of aramid, while Fig. 7 a perspective view of the invention reinforced fiber reproduces. The phase distribution is such that aramid forms the first phase or base material and that the reinforcing particles form the second phase. Particles 12, also called the second phase, are introduced into the base material 13 and distributed. The second phase indicates a higher modulus of elasticity than that of the first phase 13 or at least indicates such mechanical and chemical properties that the elastic modulus of the reinforced aramid fiber becomes higher than that of the unreinforced aramid fiber.

The second phase 12 may for example consist of a very hard plastic, a stiffer polymer than aramid, ceramic, carbon, glass, steel, titanium, special metal alloys and / or intermetallic phases. By stiff is meant a higher modulus of elasticity than that of aramid.

The geometric shape of the particles 12 can lead to a distribution of spheres, capsules, globules, short and / or long fibers. Fig. 8 For example, Figure 4 shows various geometric embodiments of the second phase fiber-reinforcing particles which may take the form of spheres a, approximately spherical granules b, slices c, short fibers d or long fibers e distributed in the aramid matrix.

In the extreme case, the fibers of the second phase 12 may become as long as the fibers 5 of aramid and run parallel to and be incorporated as in Fig. 9 is pictured.

The distribution and density of the particles 12 is preferably homogeneous in aramid 13. In the case of short and / or long fibers, the orientation of the fibers may be random (random), as in Fig. 7 shown, or have a preferred direction relative to the longitudinal direction of the fiber 5, such as in Fig. 9 ,

Due to the action of the reinforcing particles 12 in the first phase 13, the modulus of elasticity of the entire fiber 5 in the longitudinal direction and / or in the transverse direction of the fiber 5 is increased. Also, the breaking tension of the rope is increased and the life of the rope is prolonged compared to the case of the unreinforced rope.

The introduction of the second phase, in order to optimize the mechanical properties of an aramid rope, makes it possible to avoid the known disadvantages of using such cables as lifting means for elevators. The modulus of elasticity of the entire rope is increased in the longitudinal direction and in the transverse direction so that the requirements of the rope can be achieved as a support means for a lift system with a large lifting height.

The life and the breaking and tensile strength of the reinforced according to the invention aramid rope are substantially increased and thus satisfy by far the requirements placed in the area of elevators safety. At the same time, the weight of the reinforced aramid rope remains substantially smaller than that of a corresponding steel rope of comparable strength.

Methods for producing a microfiber-reinforced aramid fiber such as those of the present invention are described, for example, in US Pat US 2001/0031594 disclosed.

The base material 13 of the fiber 5 may be replaced by other synthetic compositions having sufficient strength. The reinforcing particles 12 moreover allow the use of materials as green material 13, which would not be possible without the positive effect of the reinforcement.

The introduction of reinforcing particles 12 in the first phase 13 is also conceivable in elevator ropes, which have a different structure and arrangement of the strands than those of in Fig. 5 have shown rope.

Besides elevator ropes, elevator belts can also be reinforced by particles 12 and thus have more suitable mechanical properties in order to be used as lifting or blowing agent for lifts.

Claims (7)

1. Plastics material cable or belt for lifts (1), with load-bearing strands (4), which strands consist of several fibres (5) and are surrounded by a sheath (2), characterised in that the material of the fibres (5) consists of at least two phases (12, 13).
2. Cable or belt according to claim 1, characterised in that a first phase (13) of the material of the fibres (5) consists of a base material such as plastic, synthetic compositions, aramide, Zylon, and the second phase (12) of the material of the fibres (5) consists of a reinforcing material which increases the modulus of elasticity of the fibres in the longitudinal and/or radial direction of the fibres.
3. Cable or belt according to claim 2, wherein the reinforcing material of the fibres has a higher modulus of elasticity than that of the base material.
4. Cable or belt according to any one of claims 1 to 3, wherein the reinforcing material is arranged and distributed in the form of long and/or short fibres, capsules, spheres, in the base material, which forms a matrix.
5. Lift with a plastics material cable or belt with load-bearing strands according to any one of claims 1 to 4.
6. Method of producing a lift plastics material cable or lift belt with load-bearing strands, which strands consist of several fibres and are surrounded by a sheath, characterised in that at least two phases are combined and/or mixed in order to form the fibres.
7. Method of producing a lift cable or lift belt according to claim 6, characterised in that a first phase of the material of the fibres consists of a base material such as plastic, synthetic compositions, aramide, Zylon, and the second phase of the material of the fibres consists of a reinforcing material which increases the modulus of elasticity of the fibres in the longitudinal and/or radial direction of the fibres.

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