HK1081513B - Elevator - Google Patents

Description

Elevator with a movable elevator car

Technical Field

The present invention relates to an elevator.

Background

One of the objectives in elevator development work is to achieve efficient and economical utilization of building space. In recent years, this development work has produced, among other things, a variety of machineroom-less elevator solutions. Some good examples of elevator without machine room are disclosed in specifications EP 0631967(a1) and EP 0631968. The elevators described in these specifications are fairly efficient in respect of space utilization as they have made it possible to eliminate the space required for the elevator machine room in the building without enlarging the elevator shaft. In the elevators disclosed in these specifications, the machine is compact in at least one direction, but in other directions it may have much larger dimensions than a conventional elevator machine.

In these substantially good elevator solutions, the space required by the hoisting machine limits the freedom of choice in elevator lay-out solutions. A certain space is needed to ensure the passage of the hoisting ropes. It is difficult to reduce the space required by the elevator car itself on its track, and likewise the space required by the counterweight, at least at a reasonable cost and without impairing elevator performance and operational quality. In a traction sheave elevator without machine room it is difficult to mount the hoisting machine in the elevator shaft, especially in solutions with machine above, because the hoisting machine is a fairly large entity of considerable weight. Especially in the case of larger loads, speeds and/or hoisting heights, the size and weight of the machine are a problem regarding installation, even to such an extent that the required machine size and weight have in practice limited the scope of application of the concept of elevator without machine room, or at least retarded the introduction of said concept in larger elevators.

Specification WO 99/43589 discloses an elevator suspended with flat belts, in which a relatively small diverting diameter on the traction sheave and diverting pulleys is achieved. A problem with this solution is, however, a number of limitations concerning lay-out solutions, arrangement of the components in the elevator shaft and alignment of the diverting pulleys. In addition, the alignment of polyurethane coated belts with steel load bearing parts inside is problematic in situations such as car tilting. To avoid undesired vibrations, an elevator so implemented needs to be built fairly sturdy, at least in terms of the machine and/or the various components supporting the machine. The heavy construction of the other parts of the elevator needed to maintain alignment between the traction sheave and the diverting pulleys also increases the weight and cost of the elevator. Moreover, installing and adjusting such a system is a difficult task requiring great precision.

On the other hand, to achieve smaller rope deflection diameters, various rope constructions have been used in which the load-bearing part is made of synthetic fibers. Such a solution is unstable and the ropes thus obtained are lighter than steel wire ropes, but at least in the case of elevators designed for the most common hoisting heights, man-made fibre ropes do not offer any significant advantage, especially because they are very expensive compared to steel wire ropes.

Disclosure of Invention

The object of the present invention is to achieve at least one of the following objects. On the one hand, the object of the invention is to develop the elevator without machine room further so that the space in the building and elevator shaft can be utilized more efficiently than before. This means that the elevator must be designed so that it can be installed in a fairly narrow elevator shaft if necessary. In another aspect, the object of the invention is to reduce the size and/or weight of an elevator or at least of an elevator machine.

The object of the invention should be achieved without affecting the possibilities of changing the basic layout of the elevator.

According to the invention an elevator is provided, in which elevator a hoisting machine engages a set of hoisting ropes via a traction sheave, said set of hoisting ropes having a load-bearing part twisted from steel wires of circular and/or non-circular cross-section, and in which elevator there is a diverting pulley of which part is made larger than the traction sheave, and the weight of the hoisting machine is at most about 1/5 of the weight of the nominal load of the elevator.

Preferably all diverting pulleys are made larger than the traction sheave.

Preferably the strength of the steel wires of the hoisting ropes is greater than 2300N/mm²And less than 2700N/mm²。

Preferably the cross-sectional area of the steel wires of the hoisting ropes is larger than 0.015mm²And less than 0.2mm²And the wires of the hoisting ropes have a wire thickness of more than 2000N/mm²The strength of (2).

Preferably the outer diameter of the traction sheave driven by the elevator hoisting machine is at most 250 mm.

Preferably the weight of the elevator hoisting machine is at most 100 kg.

Preferably, the governor rope has a diameter greater than the diameter of the hoist rope.

Preferably, the governor rope has a diameter equal to the diameter of the hoist rope.

Preferably the weight of the elevator hoisting machine is 1/6% of the nominal load at most.

Preferably the total weight of the elevator hoisting machine and its supporting elements is at most 1/5 of the nominal load.

Preferably, the diameter of each sheave (502) supporting the car is equal to or less than the height dimension of the horizontal beam (504) included in the structure supporting the car.

Preferably, the pulley (502) is at least partially disposed within a beam (504).

Preferably the track of the elevator car is in the elevator shaft.

Preferably at least part of the spaces between the strands and/or wires in the hoisting ropes is filled with rubber, polyurethane or other medium having non-fluid properties.

Preferably, the hoisting ropes have a surface made of rubber, polyurethane or other non-metallic material.

Preferably, the traction sheave is coated with a non-metallic material at least in its rope grooves.

Preferably the traction sheave is made of a non-metallic material at least in the rim portion comprising the rope grooves.

Preferably the D/D ratio is less than 40, where D is the traction sheave diameter and D is the hoisting rope thickness.

Preferably, the elevator is a machine room-less elevator.

Preferably the weight of the elevator hoisting machine is 1/8 at most the nominal load.

Preferably the weight of the elevator hoisting machine is less than 1/10 at nominal load.

Preferably the total weight of the elevator hoisting machine and its supporting elements is at most 1/8 of the nominal load. One or more of the following advantages may be obtained, among others, by applying the present invention.

It is preferable to make all or some of the diverting pulleys larger than the traction sheave. Among these larger diverting pulleys are especially those mounted in the upper part of the shaft. For example, in the case of a 4: 1 suspension, a more spacious rope passage arrangement will be obtained by using slightly larger diverting pulleys in the upper part of the shaft. Of course, this also applies to elevators with machine above, not just to elevators with machine below.

With the aid of a large diverting pulley the rope passage arrangement is relatively easy to implement, and when the diverting pulley has a large diverting radius, the ropes are not strained much when passing the diverting pulley, and the ropes are also less worn, and the service life of the ropes is extended, especially when a small traction sheave is used.

Different elevator lay-out solutions are also easier to implement when some diverting pulleys may be larger than the traction sheave, especially if a smaller traction sheave is used.

When larger diverting pulleys are used, it may be possible to use smaller traction sheaves.

The smaller traction sheave makes it possible to achieve a lightweight elevator and elevator machine.

By using a smaller coated traction sheave, the weight of the machine can easily be reduced to even about half or less of the weight of the machine currently normally used in elevators without machine room. For example, in the case of elevators designed for nominal loads below 1000kg, this means that the machine weighs 100-150kg or even less. With appropriate motor solutions and material selection it is even possible to achieve a machine weight of less than 100 kg.

A good traction sheave gripping ability and light components can lead to a significant reduction in the weight of the elevator car, and correspondingly the counterweight can also be made lighter than in current elevator solutions.

The compact machine size and the thin and essentially round ropes allow the elevator machine to be placed relatively freely in the shaft. Thus, the elevator solution can be implemented in a fairly wide variety of ways both in the case of elevators with machine above and in the case of elevators with machine below.

The elevator machine can advantageously be placed between the car and a shaft wall.

All or at least part of the weight of the elevator car and counterweight can be taken up by the elevator guide rails.

In the elevator to which the invention is applied, a central suspension arrangement of the elevator car and counterweight can be easily achieved, so that the lateral supporting forces applied to the guide rails are reduced.

The application of the invention makes it possible to utilize the cross-sectional area of the shaft effectively.

The invention reduces the installation time and the total installation cost of the elevator.

The elevator is economical to manufacture and install because many of its components are smaller and lighter than those used previously.

The governor rope and the hoist rope are usually different in their properties, and if the governor rope is thicker than the hoist rope, they can be easily identified from each other during installation; on the other hand, the governor rope and the hoisting ropes can also have an equivalent structure, which will reduce confusion about these things in elevator dispatch service and installation.

The light and thin ropes are easy to handle and allow for a significantly faster installation.

For example, in elevators intended for nominal loads below 1000kg and speeds below 2m/s, the thin and strong steel wire ropes of the invention have a diameter of the order of only 3-5 mm.

With a rope diameter of about 6mm or 8mm a fairly large and fast elevator according to the invention can be achieved.

The traction sheave and the rope pulleys are small and light compared to those used in conventional elevators.

A smaller traction sheave makes it possible to use a smaller operating brake.

A smaller traction sheave reduces torque requirements, thereby allowing a smaller motor with a smaller operating brake.

Since the traction sheave is small, a higher rotational speed is required to achieve a given car speed, which means that the same motor output can be achieved by a smaller motor.

Either coated or uncoated cords may be used.

The traction sheave and the rope pulleys may be implemented in such a way that after the coating on the pulley has been worn away, the rope will bite firmly on the pulley and thus maintain a sufficient grip between the rope and the pulley in this emergency.

The use of a smaller traction sheave makes it possible to use a smaller elevator drive motor, which means that the drive motor acquisition/manufacturing costs are reduced.

The invention can be used in gearless and geared elevator motor solutions.

Although the invention is primarily considered for use in elevators without machine room, it can also be used in elevators with machine room.

The main field of application of the invention is elevators designed for transporting people and/or freight. The invention is primarily considered for elevators whose speed range is typically about or over 1.0m/s but may e.g. be only about 0.5m/s in the case of passenger elevators. In the case of a freight elevator, too, the speed is preferably about 0.5m/s, although lower speeds may also be used for large loads.

Among both passenger and goods elevators, many of the advantages obtained by the present invention appear clearly even in elevators for only 3-4 persons, and already clearly in elevators for 6-8 persons (500-.

The elevator of the invention can be provided with elevator hoisting ropes twisted e.g. from strong round wires. On the basis of round wires, the ropes can be twisted out in many ways using wires of different or equal thickness. In the rope used in the invention the wire thickness is on average below 0.4 mm. Well-used ropes made of strong wires are those with an average wire thickness below 0.3mm or even below 0.2 mm. For example, thin wires and strong 4mm ropes can be twisted relatively economically from steel wires so that the average wire thickness in the finished rope is in the range of 0.15-0.23 mm, in which case the finest steel wires may have a thickness as small as only about 0.1 mm. Thin rope wires can easily be made strong. The rope wires used in the invention have a wire diameter of about 2000N/mm²Or higher strength. The strength of the steel wire of the rope is in a proper range of 2300-2700N/mm². In principle, a strength of up to about 3000N/mm may be used²Or higher rope wires.

Drawings

The invention will be described in detail below with the aid of examples of embodiments thereof with reference to the accompanying drawings, in which:

fig. 1 presents a diagrammatic view of a traction sheave elevator according to the invention;

fig. 2 presents a diagrammatic view of another traction sheave elevator according to the invention;

fig. 3 presents a traction sheave to which the invention is applied;

FIG. 4 illustrates a coating scheme consistent with the present invention;

fig. 5a shows a steel wire rope for use in the present invention;

fig. 5b shows another steel wire rope for use in the present invention;

fig. 5c shows a third steel wire rope for use in the present invention; and

fig. 6 illustrates a rope pulley arrangement consistent with the present invention.

Detailed Description

Fig. 1 presents a diagrammatic illustration of the structure of an elevator. The elevator is preferably a machine room-less elevator in which the drive machine 6 is placed in the elevator shaft. The elevator presented in the figure is a traction sheave elevator with machine above. The running of the elevator hoisting ropes 3 is as follows: one end of the ropes is immovably fixed to an anchorage 13 arranged in the upper part of the shaft above the path of the counterweight 2 moving along the counterweight guide rails 11. From which anchorage the ropes go downwards and are passed around diverting pulleys 9 suspending the counterweight, which diverting pulleys 9 are rotatably mounted on the counterweight 2, and from which the ropes 3 go further upwards to the traction sheave 7 of the drive machine 6, passing around the traction sheave along the rope grooves on the sheave. From the traction sheave 7 the ropes 3 go further downwards to the elevator car 1 moving along car guide rails 10, pass under the car via diverting pulleys 4 used to suspend the elevator car on the ropes, and then go further upwards from the elevator car to an anchorage 14 in the upper part of the elevator shaft, to which anchorage the second ends of the ropes 3 are fixed. The anchorage 13 in the upper part of the shaft, the traction sheave 7 and the diverting pulley 9 suspending the counterweight on the ropes are preferably so disposed in relation to each other that both the rope portion going from the anchorage 13 to the counterweight 2 and the rope portion going from the counterweight 2 to the traction sheave 7 are substantially parallel to the path of the counterweight 2. Similarly, a solution is advisable in which the anchorage 14 in the upper part of the shaft, the traction sheave 7 and the diverting pulleys 4 suspending the elevator car on the ropes are so disposed in relation to each other that the rope portion going from the anchorage 14 to the elevator car 1 and the pulley portion going from the car 1 to the traction sheave 7 are substantially parallel to the path of the elevator car 1. In this arrangement no additional diverting pulleys are needed to define the passage of the ropes in the shaft. The rope suspension acts in a substantially centred manner on the elevator car 1 provided that the rope pulleys 4 supporting the elevator car are mounted substantially symmetrically with respect to a vertical centre line passing through the centre of gravity of the elevator car 1.

The drive machine 6 placed in the elevator shaft preferably has a flat construction, in other words the machine has a small thickness compared to its width and/or height, or at least the machine is slim enough to be accommodated between the elevator car and a wall of the elevator shaft. The machine can also be placed in different ways, e.g. by placing the slim machine partly or completely between a hypothetical extension of the elevator car and a shaft wall. The elevator shaft can be provided with equipment required for the supply of power to the motor driving the traction sheave 7 as well as equipment for elevator control, both of which can be placed in a common instrument panel 8 or mounted separately from each other or integrated partly or wholly with the drive machine 6. The drive machine may be of a geared or gearless type. A preferred solution is a gearless machine comprising a permanent magnet motor. The drive machine may be fixed to a wall of the elevator shaft, to the ceiling, to a guide rail or guide rails, or to some other structure, such as a beam or bracket. In the case of an elevator with machine below, it is alternatively possible to mount the machine on the bottom of the elevator shaft. Fig. 1 presents an economical 2: 1 suspension, but the invention can also be implemented in an elevator using a 1: 1 suspension ratio, in other words in an elevator in which the hoisting ropes are connected directly to the counterweight and to the elevator car without diverting pulleys. Other suspension configurations are possible in the practice of the present invention. The elevator shown in the figure has self-acting telescopic doors, but other types of automatic doors or revolving doors can be used in the elevator of the invention.

Fig. 2 presents a diagrammatic illustration of another traction sheave elevator according to the invention, in which elevator the ropes go upwards from the machine. This type of elevator is typically a traction sheave elevator with machine below. The elevator car 101 and the counterweight 102 are suspended on the hoisting ropes 103 of the elevator. The elevator drive machine 106 is mounted in the elevator shaft, preferably in the lower part of the shaft, and the hoisting ropes are passed to the car 101 and to the counterweight 102 via diverting pulleys 104,105 placed in the upper part of the elevator shaft. The diverting pulleys 104,105 are placed in the upper part of the shaft and are preferably mounted on the same shaft by bearings, respectively, so that they can rotate independently of each other. The hoisting ropes 103 consist of at least three parallel ropes.

The elevator car 101 and the counterweight 102 move in the elevator shaft along guide rails 110 and 111 guiding their elevator and counterweight.

In fig. 2, the hoisting ropes run as follows: one end of the rope is fixed to an anchorage 112 in the upper part of the shaft, from where it goes down to the counterweight 102. The counterweight is suspended on the ropes 103 via a diverting pulley 109. From the counterweight the ropes go further upwards to a first diverting pulley 105 mounted on the guide rails 110 of the elevator and from diverting pulley 105 further to a traction sheave 107 driven by a drive machine 106. From the traction sheave, the ropes go again upwards to a second diverting pulley 104, passing around it, after which the ropes pass around a diverting pulley 108 mounted on top of the elevator car and then go further to an anchorage 113 in the upper part of the elevator shaft, to which the other end of the hoisting ropes is fixed. The elevator car is suspended on the hoisting ropes 103 by means of diverting pulleys 108. In the hoisting ropes 103 one or more rope portions between the diverting pulleys or between the diverting pulleys and the traction sheave may deviate from the exact vertical direction, which makes it easy to establish a sufficient distance between the different rope portions or a sufficient distance between the hoisting ropes and other elevator components. The traction sheave 107 and the hoisting machine 106 are preferably disposed slightly deviating from the path of the elevator car 101 and the path of the counterweight 102 so that they can be easily placed at almost any height in the elevator shaft below the diverting pulleys 104 and 105. This allows savings in shaft height if the machine is not placed directly above or below the counterweight or car. In which case the minimum height of the elevator shaft is determined solely on the basis of the path lengths of the counterweight and car and the safety spacing required above and below them. Furthermore, due to the reduced rope pulley diameters compared to earlier solutions, less space at the top or bottom of the shaft is sufficient, depending on how the rope pulleys are mounted on the elevator car and/or on the frame of the elevator car. It may sometimes be preferable to make all or some of the diverting pulleys larger than the traction sheave. These larger diverting pulleys may especially be those mounted in the upper part of the shaft. For example, in the case of a 4: 1 roping, a relatively spacious rope running arrangement will be obtained by using slightly larger diverting pulleys in the upper part of the shaft. Of course, this also applies to elevators with machine above, not just to elevators with machine below.

Fig. 3 presents a partial cross-sectional view of a rope pulley 200 applying the invention. The rope grooves 201 on the rim 206 of the rope pulley are covered by a coating 202. In the hub of the rope pulley a space 203 is formed for a bearing for mounting the rope pulley. The rope sheave is also provided with eyes 205 for bolts so that the rope sheave can be fastened with one side to an installation point on the hoisting machine 6, such as a rotating flange, to constitute a traction sheave 7, in which case no separate bearing from the hoisting machine is needed. The coating used on the traction sheave and rope pulleys may consist of rubber, polyurethane or some corresponding elastic material that increases friction. The material of the traction sheave and/or rope pulleys may also be chosen such that it constitutes a material pair together with the hoisting ropes used, so that the hoisting ropes bite firmly on the pulley after the coating on the pulley has been worn away. This may ensure a sufficient grip between the rope pulley 200 and the hoisting rope 3 in an emergency situation in which the coating 202 has worn away from the rope pulley 200. This feature allows the elevator to maintain its functionality and operational reliability in the situation in question. The traction sheave and/or rope pulleys may also be manufactured in such a way that only the rim 206 of the rope pulley 200 is made of the material forming a grip-enhancing material pair with the hoisting ropes 3. The use of strong hoisting ropes which are considerably thinner than normally allows the traction sheave and the rope pulleys to be designed with considerably smaller dimensions and sizes than when using ropes of normal size. This also makes it possible to use a smaller-sized motor with a smaller torque as the drive motor of the elevator, which results in a reduction in the motor acquisition costs. In an elevator according to the invention designed for a nominal load below 1000kg, for example, the traction sheave diameter is preferably 120-200mm, but may even be smaller than this. The traction sheave diameter depends on the thickness of the hoisting ropes used. In the elevator of the invention, the use of a smaller traction sheave, such as in the case of elevators for nominal loads below 1000kg, makes it possible to achieve a machine weight even as low as about half the weight of the machine currently used, which means that elevator machines with a weight of 100-150kg or even less can be produced. In the present invention, a machine is understood to comprise at least a traction sheave, a motor, a machine housing structure and a brake. The diameter of the traction sheave depends on the thickness of the hoisting ropes used. The diameter ratio usually employed is D/D40 or higher, where D is the traction sheave diameter and D is the hoisting rope thickness. This ratio can be reduced a little at the expense of the wear resistance of the rope. In addition, without compromising on the service life, the D/D ratio can be reduced if the number of ropes is increased at the same time, in which case the stress per rope is smaller. Such a D/D ratio of less than 40 may for example be equal to about 30 or even lower, such as 25D/D. However, a reduction of the D/D ratio to significantly below 30 tends to reduce the service life of the rope substantially, although this can be compensated by using a special construction of the rope. In practice it is difficult to achieve a D/D ratio below 20, but this can be achieved by using a rope specially designed for this purpose, although such a rope may be most likely expensive.

The weight of the elevator machine and its support elements used to hold the machine in place in the elevator shaft is at most about 1/5 of the nominal load. If the machine is exclusively or almost exclusively supported by one or more elevator and/or counterweight guide rails, the total weight of the machine and its supporting elements can be less than about 1/6 or even less than 1/8 of the nominal load. The nominal load of an elevator refers to the load determined for an elevator of a given size. The supporting elements of the elevator machine may comprise e.g. beams, brackets or suspension brackets for supporting or suspending the machine on the wall structure or ceiling of the elevator shaft or on the guide rails of the elevator or counterweight or clips for holding it fastened to the sides of the elevator guide rails. It will be easy to achieve an elevator in which the machine dead weight without supporting elements is below 1/7 for the nominal load or even about 1/10 or less for the nominal load. Basically, for a normal elevator, in which the counterweight has a weight substantially equal to the weight of the empty car plus half the nominal load, the ratio of the machine weight to the nominal load is given. As an example of the weight of the machine in an elevator given a nominal weight, when a fairly common 2: 1 roping ratio is used for a nominal load of 630kg, the combined weight of the machine and its supporting elements may be only 75kg if the traction sheave diameter is 160mm and hoisting ropes having a diameter of 4mm are used, in other words the total weight of the machine and its supporting elements is about 1/8 of the nominal load of the elevator. As another example, the total weight of the machine and its supporting elements is about 150kg with the same 2: 1 suspension ratio, the same 160mm traction sheave diameter and the same 4mm hoisting rope diameter in an elevator for a nominal load of about 1000kg, so that, in this case, the machine and its supporting elements have a total weight equal to about 1/6 of the nominal load. As a third example, consider an elevator designed for a nominal load of 1600 kg. In this case, when the suspension ratio is 2: 1, the traction sheave diameter is 240mm and the hoisting rope diameter is 6mm, the total weight of the machine and the supporting elements will be about 300kg, i.e. about 1/7 of the nominal load. By changing the hoisting rope suspension arrangement, the total weight of the machine and its supporting elements can be made lower. For example, when a 4: 1 suspension ratio, a traction sheave diameter of 160mm and a hoisting rope diameter of 4mm are used in an elevator designed for a nominal load of 500kg, a total weight of the machine and its supporting elements of about 50kg will be achieved. In this case, the total weight of the machine and its supporting elements is as little as about 1/10 of the nominal load. When the traction sheave size is reduced significantly and larger suspension ratios are applied, the motor torque output requirement drops to a fraction of the level required in the original situation. If, for example, a 4: 1 suspension ratio is used instead of a 2: 1 suspension ratio, and if a traction sheave with a diameter of 160mm is used instead of 400mm, the torque requirement drops to a fifth if the increased losses are disregarded. Thus, the size of the machine is also substantially reduced.

Fig. 4 shows a solution in which the rope groove 301 is in a coating 302 which is thinner at both sides of the rope groove than at the bottom. In such a solution the coating is placed in a basic groove 320 on the rope pulley 300 so that the deformations in the coating caused by the pressure of the rope on the coating will be small and mainly limited to the sinking of the rope surface structure into the coating. Such a solution often means in practice that the rope pulley coating consists of rope groove-specific sub-coatings separated from each other, but in view of production and other aspects it is appropriate to design the rope pulley coating such that it extends continuously over several rope grooves.

By making the coating thinner at both sides of the rope groove than at its bottom, the strain caused by the rope on the bottom of the rope groove while sinking into the rope groove is avoided or at least reduced. It is also conceivable to have a lower maximum surface pressure acting on the rope and the coating, since the pressure cannot be discharged laterally and is limited by the combined effect of the shape of the base groove 320 and the thickness variation of the coating 302 to support the rope in the rope groove 301. One method of making such a grooved coating 302 is to fill the round-bottomed base grooves 320 with coating material, and then to fill the base grooves with coating materialA semicircular rope groove 301 is formed in the coating material. The shape of the rope grooves is well maintained while the load-bearing surface layer below the ropes provides a better resistance to lateral propagation of the compressive stress generated by the ropes. The lateral spreading or adjustment of the coating by the pressure is facilitated by the thickness and elasticity of the coating and is reduced by the hardness and eventual reinforcement of the coating. The coating thickness on the bottom of the rope groove can be made larger, even up to half the rope thickness, in which case a hard and inelastic coating is required. On the other hand, if a coating thickness corresponding to only about one tenth of the rope thickness is used, the coating material may be significantly softer. An elevator for 8 people can be implemented with a coating thickness at the bottom of the groove equal to about one fifth of the rope thickness if the rope and rope load are chosen appropriately. The coating thickness should be equal to at least 2-3 times the depth of the surface structure of the rope consisting of the surface wires of the rope. Such a very thin coating, even of a thickness smaller than the thickness of the steel wires on the surface of the rope, will not necessarily endure the strain imposed on it. In practice the coating must have a thickness greater than this minimum thickness, because the coating will also have to withstand rope surface deviations that are rougher than the surface structure. Such a rougher area is formed, for example, where the difference in level between the strands of the rope is greater than the difference in level between the wires. In practice, a suitable minimum coating thickness is about 1-3 times the surface wire thickness. In the case of ropes normally used in elevators, the latter have been designed for contact with the metal rope grooves and have a thickness of 8-10mm, the thickness thus determined resulting in a coating of at least about 1mm thickness. The ropes can be made smoother in that a coating on the traction sheave causing more rope wear than the other rope pulleys of the elevator will reduce the rope wear and thus also the need to provide the ropes with thicker surface wires. Rope smoothness can naturally be improved by coating the rope with a material suitable for the purpose, such as e.g. polyurethane or equivalent. The use of thin wires makes the rope itself thinner, since thin wires can be made of a stronger material than thick wires. For example, it can be made of 0.2mm steel wireAs an elevator hoisting rope of 4mm thickness with a fairly good construction. Depending on the thickness of the hoisting rope used and/or other reasons, the steel wires in the steel wire rope may preferably have a thickness between 0.15mm and 0.5mm, in which range steel wires with good strength properties can easily be obtained, wherein even one single steel wire has a sufficient wear resistance and a sufficiently low vulnerability. The above describes a rope made of round steel wire. Using the same principle, the rope can be twisted wholly or partly from wires of non-circular cross-section. In this case, the cross-sectional area of the steel wire is preferably substantially the same as that of a round steel wire, i.e. at 0.015mm²～0.2mm²Within the range of (1). With steel wires within this thickness range, the following steel wire ropes can be easily made: having a wire strength in excess of about 2000N/mm²And the cross-sectional area of the steel wire is 0.015mm²～0.2mm²And comprises a large cross-sectional area of steel material in relation to the cross-sectional area of the rope, as is obtained for example with the Warrington construction. For carrying out the invention, it is particularly suitable to have a wire strength of 2300N/mm²～2700N/mm²Because such ropes have a high load-bearing capacity with respect to rope thickness, while the high hardness of the strong wires does not cause any significant difficulties in the use of the ropes in elevators. The traction sheave coating well suited to such a rope is obviously below 1mm thick. However, the coating should be thick enough to ensure that it will not be easily scraped off or punctured, for example by occasional sand grains or similar particles being trapped between the rope grooves and the hoisting ropes. Thus, the desired minimum coating thickness will be about 0.5-1 mm even when using a thin-wire hoisting rope. For hoisting ropes with thin-surfaced wires and, in addition, a relatively smooth surface, a coating having a thickness in the form of a + Bcosa is well suited. However, such a coating can also be applied to ropes whose surface strands contact the rope grooves at a distance from each other, because if the coating material is sufficiently hard, each strand contacting the rope grooves is supported separately and the supporting force is the same and/or as intended. In the formula A + Bcosa, A and B are constants such thatA + B is the coating thickness at the bottom of the rope groove 301 and the angle a is the angular distance from the bottom of the rope groove measured from the centre of curvature of the rope groove cross-section. The constant a is greater than or equal to zero, while the constant B is always greater than zero. The thickness of the coating, which tapers towards the edges, can also be determined in other ways than using the formula a + Bcosa, so that the elasticity decreases towards the edges of the rope groove. The elasticity of the central part of the rope groove can also be increased by making the rope groove undercut and/or by adding a part of a coating of a different material with a certain elasticity to the bottom of the rope groove, where the elasticity has been increased, in addition to the increase of the thickness of the material, by means of a material that is softer than the rest of the coating.

Fig. 5a, 5b and 5c are various cross sections of steel cord used in the present invention. The ropes in these figures all comprise thin wires 403, a coating 402 on the wires and/or partly between the wires, and in fig. 5a coating 401 over the wires. The rope shown in fig. 5b is an uncoated steel wire rope with a rubber-like filler added to its inner structure, while fig. 5a shows a steel wire rope provided with a coating in addition to the filler added to the inner structure. The rope shown in fig. 5c has a non-metallic core which may be of a solid or fibrous structure made of plastic, natural fiber (natural fiber) or some other material suitable for the purpose. The fibrous structure is good if the rope is lubricated, in which case the lubricant will accumulate inside the fibrous core. The core thus acts as a lubricant reservoir. The steel wire ropes of substantially circular cross-section used in the elevator of the invention may be coated, uncoated and/or provided with a rubber-like filler, such as e.g. polyurethane or some other suitable filler, added to the inner structure of the rope and functioning as a lubricant lubricating the rope and also balancing the pressure between the steel wires and the strands. The use of a filler makes it possible to obtain a rope which does not require a lubricant, so that its surface can be dry. The coating used in the wire rope may be made of the same or almost the same material as the filler or of a material that is more suitable for use as a coating and has properties such as friction and wear resistance properties that are more suitable for the purpose than the filler. The coating of the steel wire rope can also be made so that the coating material partly penetrates the rope or passes through the entire thickness of the rope, giving the rope the same properties as the above-mentioned filler. The use of thin and strong steel wire ropes according to the invention is possible because the steel wires used are steel wires having a particular strength, allowing the ropes to be made significantly thin compared to previously used steel wire ropes. The rope shown in fig. 5a and 5b is a steel wire rope of about 4mm diameter. For example, when a 2: 1 suspension ratio is used, the thin and strong steel cord of the invention preferably has a diameter of about 2.5-5 mm for elevators with a nominal load below 1000kg and about 5-8 mm for elevators with a nominal load above 1000 kg. In principle, it is possible to use ropes which are thinner than this, but in this case a larger amount of ropes will be needed. Also, by increasing the suspension ratio, ropes thinner than those described above can be used for the respective loads, and at the same time a smaller and lighter elevator machine can be achieved.

Fig. 6 illustrates the arrangement of the rope pulleys 502 connected to a horizontal beam 504 comprised in the structure supporting the elevator car 501 in relation to the beam 204, said rope pulleys being intended to support the elevator car and the associated structure. The rope pulley 502 shown in the figure may have a height equal to or less than the beam 504 comprised in the structure. The beam 504 supporting the elevator car 501 can be located either below or above the elevator car. The rope pulley 502 may be arranged completely or partly inside the beam 504, as shown in the figure. The hoisting ropes 503 of the elevator in the figure run as follows: the hoisting ropes 503 run to a coated rope pulley 502 connected to a beam 504 comprised in the structure supporting the elevator car 501, from which pulley the hoisting ropes run further under the elevator car, protected by the beam e.g. in a cavity 506 in the beam, and then go further via a second rope pulley placed on the other side of the elevator car. The elevator car 501 rests on beams 504 comprised in the structure on shock absorbers 505 placed between them. The beam 504 also functions as a rope guard for the hoisting rope 503. Beam 504 may be an C, U, I, Z section beam or a hollow beam or equivalent.

It is obvious to the person skilled in the art that different embodiments of the invention are not limited to the examples described above, but that they may be varied within the scope of the invention. The number of times the hoisting ropes are passed between the upper part of the elevator shaft and the counterweight or elevator car is not a very decisive question as regards the basic advantages of the invention, for example, although it is possible to achieve some additional advantages by using a number of rope passes. In general, embodiments should be implemented such that the ropes are passed to the elevator car at most as many times as to the counterweight. It is also obvious that the hoisting ropes do not necessarily need to pass under the car. In accordance with the examples presented above, the skilled person can vary the embodiment of the invention in that instead of coated metal wheels the traction sheaves and rope pulleys can also be uncoated metal wheels or uncoated wheels made of some other material suited to the purpose.

It is further obvious to the person skilled in the art that the coating with non-metallic material, the metallic traction sheaves and rope pulleys used in the invention, at least in the area of their grooves, may be implemented using a coating material consisting of e.g. rubber, polyurethane or some other material suited to the purpose.

It is obvious to the person skilled in the art that the elevator car, the counterweight and the machine unit can be arranged in the cross-section of the elevator shaft in a manner differing from the lay-out described in the examples. Such a different lay-out may be, for example, one in which the machine and counterweight are located behind the car as seen from the shaft door and the ropes pass diagonally below the car with respect to the bottom of the car. Passing the ropes under the car in a diagonal or otherwise oblique direction relative to the shape of the bottom also provides advantages in other types of suspension arrangements when the suspension of the car on the ropes is made symmetrical relative to the centre of mass of the elevator.

It is further obvious to the person skilled in the art that the equipment needed for supplying power to the motor and the equipment needed for elevator control can be placed elsewhere than in connection with the machine unit, e.g. in a separate instrument cabinet. It is also obvious to the person skilled in the art that an elevator applying the invention can be equipped differently from the examples described above.

It is also obvious to the person skilled in the art that instead of the filled rope shown in fig. 5a and 5b, the invention can be implemented using a rope without filler, which is either lubricated or unlubricated. Furthermore, it is also obvious to the person skilled in the art that the ropes can be twisted in many different ways.

As the average value of the wire thicknesses a statistical average or an average, such as a geometric or arithmetic average, of all the wire thicknesses of the hoisting ropes is used. For the statistical average or mean, a standard deviation, gaussian distribution, mean square error (mean error square), variance (deviationsquare) method, or the like can be employed. Often wires of the same thickness are used in a rope, in which case the average thickness describes the thickness of each wire of the rope. If it is desired to use wires of different thicknesses, the maximum wire thickness in the rope should preferably not exceed 4 times, more preferably 3 times or most preferably 2 times the average wire thickness for the same reason.

Claims (22)

1. Elevator, in which elevator a hoisting machine engages a set of hoisting ropes via a traction sheave, said set of hoisting ropes having a load-bearing part twisted from steel wires of circular and/or non-circular cross-section, and in which elevator there are diverting pulleys, of which part is made larger than the traction sheave, and the weight of the hoisting machine is 1/5 at most the weight of the nominal load of the elevator.

2. Elevator according to claim 1, characterized in that all diverting pulleys are made larger than the traction sheave.

3. Elevator according to claim 1 or 2, characterized in that the strength of the steel wires of the hoisting ropes is greater than 2300N/mm²And less than 2700N/mm²。

4. Elevator according to claim 1 or 2, characterized in that the cross-sectional area of the steel wires of the hoisting ropes is greater than 0.015mm²And less than 0.2mm²And the wires of the hoisting ropes have a wire thickness of more than 2000N/mm²The strength of (2).

5. Elevator according to claim 1 or 2, characterized in that the outer diameter of the traction sheave driven by the hoisting machine of the elevator is at most 250 mm.

6. Elevator according to claim 1 or 2, characterized in that the weight of the hoisting machine of the elevator is at most 100 kg.

7. Elevator according to claim 1 or 2, characterized in that the diameter of the governor rope is larger than the diameter of the hoisting ropes.

8. Elevator according to claim 1 or 2, characterized in that the diameter of the governor rope is equal to the diameter of the hoisting ropes.

9. Elevator according to claim 1 or 2, characterized in that the weight of the hoisting machine of the elevator is at most 1/6 of the nominal load.

10. Elevator according to claim 1 or 2, characterized in that the total weight of the elevator hoisting machine and its supporting elements is at most 1/5 of the nominal load.

11. Elevator according to claim 1 or 2, characterized in that the diameter of the pulleys (502) supporting the car is equal to or smaller than the height dimension of the horizontal beam (504) comprised in the structure supporting the car.

12. Elevator according to claim 1 or 2, characterized in that the pulley (502) is at least partly arranged in the beam (504).

13. Elevator according to claim 1 or 2, characterized in that the track of the elevator car is in the elevator shaft.

14. Elevator according to claim 1 or 2, characterized in that at least part of the spaces between the strands and/or wires in the hoisting ropes is filled with rubber or polyurethane.

15. Elevator according to claim 1 or 2, characterized in that the hoisting ropes have a surface made of rubber or polyurethane.

16. Elevator according to claim 1 or 2, characterized in that the traction sheave is coated with a non-metallic material at least in its rope grooves.

17. Elevator according to claim 1 or 2, characterized in that the traction sheave is made of non-metallic material at least in the rim part comprising the rope grooves.

18. Elevator according to claim 1 or 2, characterized in that the ratio D/D is less than 40, where D is the traction sheave diameter and D is the hoisting rope thickness.

19. Elevator according to claim 1 or 2, characterized in that the elevator is a machine room free elevator.

20. Elevator according to claim 9, characterized in that the weight of the hoisting machine of the elevator is at most 1/8 of the nominal load.

21. Elevator according to claim 9, characterized in that the weight of the elevator hoisting machine is less than 1/10 of the nominal load.

22. Elevator according to claim 10, characterized in that the total weight of the elevator hoisting machine and its supporting elements is at most 1/8 of the nominal load.