1. Field of the Invention
The present invention relates to a hoisting device rope, to an elevator as and to a method of using the hoisting device rope and the elevator.
2. Description of Background Art
Elevator ropes are generally made by braiding from metallic wires or strands and have a substantially round cross-sectional shape. A problem with metallic ropes is, due to the material properties of metal, that they have a high weight and a large thickness in relation to their tensile strength and tensile stiffness. There are also background-art belt-shaped elevator ropes which have a width larger than their thickness. Previously known are, e.g. solutions in which the load-bearing part of a belt-like elevator hoisting rope consists of metal wires coated with a soft material that protects the wires and increases the friction between the belt and the drive sheave. Due to the metal wires, such a solution involves the problem of high weight. On the other hand, a solution described in the specification of EP 1640307 A2 proposes the use of aramid braids as the load-bearing part. A problem with aramid material is mediocre tensile stiffness and tensile strength. Moreover, the behavior of aramid at high temperatures is problematic and constitutes a safety hazard. A further problem with solutions based on a braided construction is that the braiding reduces the stiffness and strength of the rope. In addition, the separate fibers of the braiding can undergo movement relative to each other in connection with bending of the rope, the wear of the fibers being thus increased. Tensile stiffness and thermal stability are also a problem in the solution proposed by the specification of WO 1998/029326, in which the load-bearing part used is an aramid fabric surrounded by polyurethane.
An object of the present invention is, among others, to eliminate the above-mentioned drawbacks of the background-art solutions. A specific object of the invention is to improve the roping of a hoisting device, particularly a passenger elevator.
The aim of the invention is to produce one or more the following advantages, among others:
In elevator systems, the rope of the invention can be used as a safe means of supporting and/or moving an elevator car, a counterweight or both. The rope of the invention is applicable for use both in elevators with counterweight and in elevators without counterweight. In addition, it can also be used in conjunction with other devices, e.g. as a crane hoisting rope. The low weight of the rope provides an advantage especially in acceleration situations, because the energy required by changes in the speed of the rope depends on its mass. The low weight further provides an advantage in rope systems requiring separate compensating ropes, because the need for compensating ropes is reduced or eliminated altogether. The low weight also allows easier handling of the ropes.
The hoisting rope for a hoisting device according to the invention are presented in the appended claims. Inventive embodiments are also presented in the description part and drawings of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims below. The inventive content may also consist of several separate inventions, especially if the invention is considered in light of explicit or implicit sub-tasks or with respect to advantages or sets of advantages achieved. In this case, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts. The features of different embodiments of the invention can be applied in connection with other embodiments within the scope of the basic inventive concept.
According to the invention, the width of the hoisting rope for a hoisting device is larger than its thickness in a transverse direction of the rope. The rope comprises a load-bearing part made of a composite material, which composite material comprises non-metallic reinforcing fibers in a polymer matrix, said reinforcing fibers consisting of carbon fiber or glass fiber. The structure and choice of material make it possible to achieve low-weight hoisting ropes having a thin construction in the bending direction, a good tensile stiffness and tensile strength and an improved thermal stability. In addition, the rope structure remains substantially unchanged at bending, which contributes towards a long service life.
In an embodiment of the invention, the aforesaid reinforcing fibers are oriented in a longitudinal direction of the rope, i.e. in a direction parallel to the longitudinal direction of the rope. Thus, forces are distributed on the fibers in the direction of the tensile force, and additionally the straight fibers behave at bending in a more advantageous manner than do fibers arranged e.g. in a spiral or crosswise pattern. The load-bearing part, consisting of straight fibers bound together by a polymer matrix to form an integral element, retains its shape and structure well at bending.
In an embodiment of the invention, individual fibers are homogeneously distributed in the aforesaid matrix. In other words, the reinforcing fibers are substantially uniformly distributed in the said load-bearing part.
In an embodiment of the invention, said reinforcing fibers are bound together as an integral load-bearing part by said polymer matrix.
In an embodiment of the invention, said reinforcing fibers are continuous fibers oriented in the lengthwise direction of the rope and preferably extending throughout the length of the rope.
In an embodiment of the invention, said load-bearing part consists of straight reinforcing fibers parallel to the lengthwise direction of the rope and bound together by a polymer matrix to form an integral element.
In an embodiment of the invention, substantially all of the reinforcing fibers of said load-bearing part are oriented in the lengthwise direction of the rope.
In an embodiment of the invention, said load-bearing part is an integral elongated body. In other words, the structures forming the load-bearing part are in mutual contact. The fibers are bound in the matrix preferably by a chemical bond, preferably by hydrogen bonding and/or covalent bonding.
In an embodiment of the invention, the structure of the rope continues as a substantially uniform structure throughout the length of the rope.
In an embodiment of the invention, the structure of the load-bearing part continues as a substantially uniform structure throughout the length of the rope.
In an embodiment of the invention, substantially all of the reinforcing fibers of said load-bearing part extend in the lengthwise direction of the rope. Thus, the reinforcing fibers extending in the longitudinal direction of the rope can be adapted to carry most of the load.
In an embodiment of the invention, the polymer matrix of the rope consists of non-elastomeric material. Thus, a structure is achieved in which the matrix provides a substantial support for the reinforcing fibers. The advantages include a longer service life and the possibility of employing smaller bending radii.
In an embodiment of the invention, the polymer matrix comprises epoxy, polyester, phenolic plastic or vinyl ester. These hard materials together with aforesaid reinforcing fibers lead to an advantageous material combination that provides i.a. an advantageous behavior of the rope at bending.
In an embodiment of the invention, the load-bearing part is a stiff, unitary coherent elongated bar-shaped body which returns straight when free of external bending. For this reason also the rope behaves in this manner.
In an embodiment of the invention, the coefficient of elasticity (E) of the polymer matrix is greater than 2 GPa, preferably greater than 2.5 GPa, more preferably in the range of 2.5-10 GPa, and most preferably in the range of 2.5-3.5 GPa.
In an embodiment of the invention, over 50% of the cross-sectional square area of the load-bearing part consists of said reinforcing fiber, preferably so that 50%-80% consists of said reinforcing fiber, more preferably so that 55%-70% consists of said reinforcing fiber, and most preferably so that about 60% of said area consists of reinforcing fiber and about 40% of matrix material. This allows advantageous strength properties to be achieved while the amount of matrix material is still sufficient to adequately surround the fibers bound together by it.
In an embodiment of the invention, the reinforcing fibers together with the matrix material form an integral load-bearing part, inside which substantially no chafing relative motion between fibers or between fibers and matrix takes place when the rope is being bent. The advantages include a long service life of the rope and advantageous behavior at bending.
In an embodiment of the invention, the load-bearing part(s) covers/cover a main proportion of the cross-section of the rope. Thus, a main proportion of the rope structure participates in supporting the load. The composite material can also be easily molded into such a form.
In an embodiment of the invention, the width of the load-bearing part of the rope is larger than its thickness in a transverse direction of the rope. The rope can therefore withstand bending with a small radius.
In an embodiment of the invention, the rope comprises a number of aforesaid load-bearing parts side by side. In this way, the liability to failure of the composite part can be reduced, because the width/thickness ratio of the rope can be increased without increasing the width/thickness ratio of an individual composite part too much.
In an embodiment of the invention, the reinforcing fibers consist of carbon fiber. In this way, a light construction and a good tensile stiffness and tensile strength as well as good thermal properties are achieved.
In an embodiment of the invention, the rope additionally comprises outside the composite part at least one metallic element, such as a wire, lath or metallic grid. This renders the belt less liable to damage by shear.
In an embodiment of the invention, the aforesaid polymer matrix consists of epoxy.
In an embodiment of the invention, the load-bearing part is surrounded by a polymer layer. The belt surface can thus be protected against mechanical wear and humidity, among other things. This also allows the frictional coefficient of the rope to be adjusted to a sufficient value. The polymer layer preferably consists of elastomer, most preferably high-friction elastomer, such as e.g. polyurethane.
In an embodiment of the invention, the load-bearing part consists of the aforesaid polymer matrix, of the reinforcing fibers bound together by the polymer matrix, and of a coating that may be provided around the fibers, and of auxiliary materials possibly comprised within the polymer matrix.
According to the invention, the elevator comprises a drive sheave, an elevator car and a rope system for moving the elevator car by means of the drive sheave, said rope system comprising at least one rope whose width is larger than its thickness in a transverse direction of the rope. The rope comprises a load-bearing part made of a composite material comprising reinforcing fibers in a polymer matrix. The said reinforcing fibers consist of carbon fiber or glass fiber. This provides the advantage that the elevator ropes are low-weight ropes and advantageous in respect of heat resistance. An energy efficient elevator is also thus achieved. An elevator can thus be implemented even without using any compensating ropes at all. If desirable, the elevator can be implemented using a small-diameter drive sheave. The elevator is also safe, reliable and simple and has a long service life.
In an embodiment of the invention, said elevator rope is a hoisting device rope as described above.
In an embodiment of the invention, the elevator has been arranged to move the elevator car and counterweight by means of said rope. The elevator rope is preferably connected to the counterweight and elevator car with a 1:1 hoisting ratio, but could alternatively be connected with a 2:1 hoisting ratio.
In an embodiment of the invention, the elevator comprises a first belt-like rope or rope portion placed against a pulley, preferably the drive sheave, and a second belt-like rope or rope portion placed against the first rope or rope portion, and that the said ropes or rope portions are fitted on the circumference of the drive sheave one over the other as seen from the direction of the bending radius. The ropes are thus set compactly on the pulley, allowing a small pulley to be used.
In an embodiment of the invention, the elevator comprises a number of ropes fitted side by side and one over the other against the circumference of the drive sheave. The ropes are thus set compactly on the pulley.
In an embodiment of the invention, the first rope or rope portion is connected to the second rope or rope portion placed against it by a chain, rope, belt or equivalent passed around a diverting pulley mounted on the elevator car and/or counterweight. This allows compensation of the speed difference between the hoisting ropes moving at different speeds.
In an embodiment of the invention, the belt-like rope passes around a first diverting pulley, on which the rope is bent in a first bending direction, after which the rope passes around a second diverting pulley, on which the rope is bent in a second bending direction, this second bending direction being substantially opposite to the first bending direction. The rope span is thus freely adjustable, because changes in bending direction are less detrimental to a belt whose structure does not undergo any substantial change at bending. The properties of carbon fiber also contribute to the same effect.
In an embodiment of the invention, the elevator has been implemented without compensating ropes. This is particularly advantageous in an elevator according to the invention in which the rope used in the rope system is of a design as defined above. The advantages include energy efficiency and a simple elevator construction. In this case it is preferable to provide the counterweight with bounce-limiting means.
In an embodiment of the invention, the elevator is an elevator with counterweight, having a hoisting height of over 30 meters, preferably 30-80 meters, most preferably 40-80 meters, said elevator being implemented without compensating ropes. The elevator thus implemented is simpler than earlier elevators and yet energy efficient.
In an embodiment of the invention, the elevator has a hoisting height of over 75 meters, preferably over 100 meters, more preferably over 150 meters, most preferably over 250 meters. The advantages of the invention are apparent especially in elevators having a large hoisting height, because normally in elevators with a large hoisting height the mass of the hoisting ropes constitutes most of the total mass to be moved. Therefore, when provided with a rope according to the present invention, an elevator having a large hoisting height is considerably more energy efficient than earlier elevators. An elevator thus implemented is also technically simpler, more material efficient and cheaper to manufacture, because e.g. the masses to be braked have been reduced. The effects of this are reflected on most of the structural components of the elevator regarding dimensioning. The invention is well applicable for use as a high-rise elevator or a mega high-rise elevator.
In the use according to the invention, a hoisting device rope according to one of the above definitions is used as the hoisting rope of an elevator, especially a passenger elevator. One of the advantages is an improved energy efficiency of the elevator.
In an embodiment of the invention, a hoisting device rope according to one of the above definitions is used as the hoisting rope of an elevator according to one of the above definitions. The rope is particularly well applicable for use in high-rise elevators and/or to reduce the need for a compensating rope.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
a-1m are diagrammatic illustrations of the rope of the invention, each representing a different embodiment;
a-1m present diagrams representing preferred cross-sections of hoisting ropes, preferably for a passenger elevator, according to different embodiments of the invention as seen from the lengthwise direction of the ropes. The rope (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130) represented by
The rope 10 presented in
The rope 20 presented in
The rope 40 presented in
The rope 50 presented in
The rope 60 presented in
The rope 70 presented in
The rope 80 presented in
The rope 90 presented in
The rope 110 presented in
The rope 120 presented in
The rope 130 presented in
Each one of the above-described ropes comprises at least one integral load-bearing composite part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121) containing synthetic reinforcing fibers embedded in a polymer matrix. The reinforcing fibers are most preferably continuous fibers. They are oriented substantially in the lengthwise direction of the rope, so that a tensile stress is automatically applied to the fibers in their lengthwise direction. The matrix surrounding the reinforcing fibers keeps the fibers in substantially unchanging positions relative to each other. Being slightly elastic, the matrix serves as a means of equalizing the distribution of the force applied to the fibers and reduces inter-fiber contacts and internal wear of the rope, thus increasing the service life of the rope. Eventual longitudinal inter-fiber motion consists in elastic shear exerted on the matrix, but the main effect occurring at bending consists in stretching of all materials of the composite part and not in relative motion between them. The reinforcing fibers most preferably consist of carbon fiber, permitting characteristics such as good tensile stiffness, low-weight structure and good thermal properties to be achieved. Alternatively, a reinforcement suited for some uses is glass fiber reinforcement, which provides inter alia a better electric insulation. In this case, the rope has a somewhat lower tensile stiffness, so it is possible to use small-diameter drive sheaves. The composite matrix, in which individual fibers are distributed as homogeneously as possible, most preferably consists of epoxy, which has a good adhesion to reinforcements and a good strength and behaves advantageously in combination with glass and carbon fiber. Alternatively, it is possible to use, e.g. polyester or vinyl ester. Most preferably the composite part (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130) comprises about 60% carbon fiber and 40% epoxy. As stated above, the rope may comprise a polymer layer 1. The polymer layer 1 preferably consists of elastomer, most preferably high-friction elastomer, such as, e.g. polyurethane, so that the friction between the drive sheave and the rope will be sufficient for moving the rope.
The table below shows the advantageous properties of carbon fiber and glass fiber. They have good strength and stiffness properties while also having a good thermal resistance, which is important in elevators, because a poor thermal resistance may result in damage to the hoisting ropes or even in the ropes catching fire, which is a safety hazard. A good thermal conductivity contributes inter alia to the transmission of frictional heat, thereby reducing excessive heating of the drive sheave or accumulation of heat in the rope elements.
An advantageous hoisting height range for the elevator presented in
The ropes described are also well applicable for use in counterweighted elevators, e.g. passenger elevators in residential buildings, that have a hoisting height of over 30 m. In the case of such hoisting heights, compensating ropes have traditionally been necessary. The present invention allows the mass of compensating ropes to be reduced or even eliminated altogether. In this respect, the ropes described here are even better applicable for use in elevators having a hoisting height of 30-80 meters, because in these elevators the need for a compensating rope can even be eliminated altogether. However, the hoisting height is most preferably over 40 m, because in the case of such heights the need for a compensating rope is most critical, and below 80 m, in which height range, by using low-weight ropes, the elevator can, if desirable, still be implemented even without using compensating ropes at all.
In the present application, load-bearing part' refers to a rope element that carries a significant proportion of the load imposed on the rope in its longitudinal direction, e.g. of the load imposed on the rope by an elevator car and/or counterweight supported by the rope. The load produces in the load-bearing part a tension in the longitudinal direction of the rope, which tension is transmitted further in the longitudinal direction of the rope inside the load-bearing part in question. Thus, the load-bearing part can, e.g. transmit the longitudinal force imposed on the rope by the drive sheave to the counterweight and/or elevator car in order to move them. For example in
As mentioned above, the reinforcing fibers of the load-bearing part in the rope (10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 8, A, B) of the invention for a hoisting device, especially a rope for a passenger elevator, are preferably continuous fibers. Thus the fibers are preferably long fibers, most preferably extending throughout the entire length of the rope. Therefore, the rope can be produced by coiling the reinforcing fibers from a continuous fiber tow, into which a polymer matrix is absorbed. Substantially all of the reinforcing fibers of the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 121) are preferably made of one and the same material.
As explained above, the reinforcing fibers in the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121) are in a polymer matrix. This means that, in the invention, individual reinforcing fibers are bound together by a polymer matrix, e.g. by immersing them during manufacture into polymer matrix material. Therefore, individual reinforcing fibers bound together by the polymer matrix have between them some polymer of the matrix. In the invention, a large quantity of reinforcing fibers bound together and extending in the longitudinal direction of the rope are distributed in the polymer matrix. The reinforcing fibers are preferably distributed substantially uniformly, i.e. homogeneously in the polymer matrix, so that the load-bearing part is as homogeneous as possible as observed in the direction of the cross-section of the rope. In other words, the fiber density in the cross-section of the load-bearing part thus does not vary greatly. The reinforcing fibers together with the matrix constitute a load-bearing part, inside which no chafing relative motion takes place when the rope is being bent. In the invention, individual reinforcing fibers in the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121, 131) are mainly surrounded by the polymer matrix, but fiber-fiber contacts may occur here and there because it is difficult to control the positions of individual fibers relative to each other during their simultaneous impregnation with polymer matrix, and, on the other hand, complete elimination of incidental fiber-fiber contacts is not an absolute necessity regarding the functionality of the invention. However, if their incidental occurrences are to be reduced, then it is possible to pre-coat individual reinforcing fibers so that they already have a polymer coating around them before the individual reinforcing fibers are bound together.
In the invention, individual reinforcing fibers of the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121, 131) comprise polymer matrix material around them. The polymer matrix is thus placed immediately against the reinforcing fiber, although between them there may be a thin coating on the reinforcing fiber, e.g. a primer arranged on the surface of the reinforcing fiber during production to improve chemical adhesion to the matrix material. Individual reinforcing fibers are uniformly distributed in in the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121, 131) so that individual reinforcing fibers have some matrix polymer between them. Preferably most of the spaces between individual reinforcing fibers in the load-bearing part are filled with matrix polymer. Most preferably substantially all of the spaces between individual reinforcing fibers in the load-bearing part are filled with matrix polymer. In the inter-fiber areas there may appear pores, but it is preferable to minimize the number of these.
The matrix of the load-bearing part (11, 21, 31, 41, 51, 61, 71, 81, 91, 101, 111, 121, 131) most preferably has hard material properties. A hard matrix helps support the reinforcing fibers especially when the rope is being bent. At bending, the reinforcing fibers closest to the outer surface of the bent rope are subjected to tension whereas the carbon fibers closest to the inner surface are subjected to compression in their lengthwise direction. Compression tends to cause the reinforcing fibers to buckle. By selecting a hard material for the polymer matrix, it is possible to prevent buckling of fibers, because a hard material can provide support for the fibers and thus prevent them from buckling and equalize tensions within the rope. Thus it is preferable, inter alia to permit reduction of the bending radius of the rope, to use a polymer matrix consisting of a polymer that is hard, preferably other than an elastomer (an example of an elastomer: rubber) or similar elastically behaving or yielding material. The most preferable materials are epoxy, polyester, phenolic plastic or vinyl ester. The polymer matrix is preferably so hard that its coefficient of elasticity (E) is over 2 GPa, most preferably over 2.5 GPa. In this case, the coefficient of elasticity is preferably in the range of 2.5-10 GPa, most preferably in the range of 2.5-3.5 GPa.
In the method of using according to the invention, a rope as described in connection with one of
It is obvious that the cross-sections described in the present application can also be utilized in ropes in which the composite has been replaced with some other material, such as e.g. metal. It is likewise obvious that a rope comprising a straight composite load-bearing part may have some other cross-sectional shape than those described, e.g. a round or oval shape.
The advantages of the invention will be the more pronounced, the greater the hoisting height of the elevator. By utilizing ropes according to the invention, it is possible to achieve a mega-high-rise elevator having a hoisting height even as large as about 500 meters. Implementing hoisting heights of this order with prior-art ropes has been practically impossible or at least economically unreasonable. For example, if prior-art ropes in which the load-bearing part comprises metal braidings were used, the hoisting ropes would weigh up to tens of thousands of kilograms. Consequently, the mass of the hoisting ropes would be considerably greater than the payload.
The invention has been described in the application from different points of view. Although substantially the same invention can be defined in different ways, entities defined by definitions starting from different points of view may slightly differ from each other and thus constitute separate inventions independently of each other.
It is obvious to one having ordinary skill in the art that the invention is not exclusively limited to the embodiments described above, in which the invention has been described by way of example, but that many variations and different embodiments of the invention are possible within the scope of the inventive concept defined in the claims presented below. Thus it is obvious that the ropes described may be provided with a cogged surface or some other type of patterned surface to produce a positive contact with the drive sheave. It is also obvious that the rectangular composite parts presented in
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
Number | Date | Country | Kind |
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20080045 | Jan 2008 | FI | national |
20080538 | Sep 2008 | FI | national |
This application is a Continuation of PCT/FI2009/000018 filed on Jan. 15, 2009, and priority is claimed under 35 U.S.C. §120. PCT/FI2009/000018 claims priority under 35 U.S.C. §119(a) on Patent Application No. FI 20080045 and FI 20080538, filed in Finland on Jan. 18, 2008 and Sep. 25, 2008, respectively. The entirety of each of the above-identified applications is incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/FI2009/000018 | Jan 2009 | US |
Child | 12838156 | US |