TRACTION MEMBER ARRANGEMENT IMPLEMENTED WITH A BELT-TYPE STRUCTURE, ELEVATOR, AND USE OF TRACTION MEMBERS OF THE TRACTION MEMBER ARRANGEMENT IN THE ELEVATOR The object of the invention is belt-type structures and the application of belt-type structures in elevators. More particularly the object of the invention is a traction member arrangement implemented with a belt-type structure as presented in the preamble of claim 1, an elevator as presented in the preamble of claim 12, and the use of traction members of the traction member arrangement in the elevator as presented in claim 21.

A problem with a belt, e.g. a toothed belt or a multigroove V-belt, that functions as a traction member and that is essentially wide with respect to its thickness is that the belt must adapt to axial tolerances of the wheels turned by the belt, because the shafts of the traction sheaves and of the diverting pulleys turned by the belt are not always sufficiently precise in the direction of the plane of rotation of the belt. In this case the difference between the tension of the center part of an unadapted belt and the tension exerted on the edges of the belt becomes too large, and the belt wears out quickly. High alignment accuracy is often needed in belt drives, in which case the fixing structures of the wheels guiding the belts and the installation to the fixing structures become expensive. Some structural solutions can in practice become almost impossible to implement. When using e.g. toothed belts the maximum angular error of the driven belt, on the one hand, and the minimum center distance permitted for the belt, on the other hand, limit the structures to be implemented.

However in belt drives in which the lengths of the belt are long, such as e.g. in elevator use, in which a belt is used as a traction member, an easily elongated belt causes many problems and therefore elongations must be minimized. In this case reinforcements must be used that are more rigid than normal, but a problem arising in these cases is that the tooth shapes must be very precise and the alignment accuracy of traction sheaves and diverting pulleys must be extremely good, because otherwise the difference between the tension of the center part of the belt and the tension exerted on the edges becomes too large, which then wears the belt.. Belts according to prior art are generally reinforced with braided or ' wire-type tension means of even thickness as reinforcements, which are all as rigid as one another in terms of their tensile strength.

With the traction member arrangement according to the invention it is advantageous to implement elevator solutions wherein the suspension ropes of the elevator car and of the counterweights or compensating weights are separated from the traction members. In this case the elevator machine is generally in the bottom part of the elevator hoistway, e.g. on the base of the elevator hoistway or close to it. This type of elevator solution provided with a traction member arrangement according to the invention is well suited to low- rise and medium-rise buildings and, owing to the even distribution of tension of the traction members, even to elevators intended for extremely tall buildings, in which one problem is that when the hoisting machine of the elevator is above, installation of the machine and peripheral structures is awkward, expensive and even dangerous. Additionally, the high-speed elevators in high-rise buildings require large fuses and there are often many elevators in one or more elevator groups. For this reason also the electric cablings needed for the elevator hoisting machines are expensive and in high-rise buildings this is even more pronounced because the electric cables from the power distribution boards below to the hoisting machines above are long. Long electric cables cause power losses and various other interferences in their immediate environment, e.g. electromagnetic interferences. The arrangement according to the invention is also suited to new elevators in low-rise buildings that previously had no elevator. In addition, the solution according to the invention is well suited to the modernization of old elevators .

A preferred embodiment solution is one wherein the elevator car is suspended in the elevator hoistway from suspension roping and the elevator car is driven from the bottom part of the elevator hoistway with drive machinery using one or more traction members, which travel (s) via a diverting pulley/diverting pulleys that is/are disposed in the bottom part of the elevator hoistway and that is/are separate from the traction sheave belonging to the drive machinery. Since the alignment between the traction sheave and the diverting pulley/diverting pulleys can, owing to the invention, clearly differ from each other, by even a degree or some degrees, the fixing means of the machine and of the diverting pulleys, and also the mounting of them, can be rather robust.

The aim of the present invention is to eliminate the aforementioned drawbacks and to achieve an inexpensive and easy-to-implement traction member arrangement, which enables the hoisting machine of the elevator to be disposed in the bottom part of the elevator hoistway even in high-rise buildings without excessive internal tensions arising from dimensional inaccuracies in the alignments of traction sheaves and diverting pulleys being exerted on the traction members. Additionally, the aim of the invention is to achieve an arrangement, which enables a number of different, easy-to- implement suspension options for an elevator with machine room below. The arrangement according to the invention is characterized by what is disclosed in the characterization part of claim 1. The elevator according to the invention is characterized by what is disclosed in the characterization part of claim 12. Other embodiments of the invention are characterized by what is disclosed in the other claims. In addition, the use in an elevator of the traction members of the traction member arrangement according to the invention is characterized by what is disclosed in claim 21.

Some inventive embodiments are also discussed in the descriptive section of the present application. The inventive content of the application can also be defined differently than in the claims presented below. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of expressions or implicit sub-tasks or from the point of view of advantages or categories 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. Likewise the different details presented in connection with each embodiment can also be applied in other embodiments. In addition it can be stated that at least some of the subordinate claims can, in at least some situations, be deemed to be inventive in their own right. The belt structure to be used in the invention can in many ways be made to be more flexible in the proximity of the edges than in the proximity of its longitudinal center line. In the proximity of the edges a more flexible belt structure can be made e.g. by using more flexible braids in the proximity of the edges than in the proximity of the center line of the belt structure or by making the distance between braids on the edges greater than it is in the proximity of the center line. One advantage, among others, of the solution according to the invention is that by means of it the use of long toothed belts and long multigroove V-belts is enabled without excessive internal tensions arising from dimensional inaccuracies in the alignments of traction sheaves and diverting pulleys being exerted on the belts. With the invention, therefore, structures are achieved wherein the attitude of consecutive belt pulleys leads to twisting of the belt and/or wherein the alignment of consecutive belt pulleys endeavors to bend the belt in the width direction of the belt. In this case it is possible to fabricate a reliably operating elevator solution, having the machine below, wherein the suspension members of the elevator car and of the counterweights or compensating weights and the traction members are separated from each other. In this case a further advantage is that the solution according to the invention can be made to be space-efficient in both the width direction and the depth direction of the elevator hoistway. Yet another advantage is that by means of the arrangement according to the invention the rope arrangements and layouts of elevators can be diversified, which enables easier layout design. Another advantage is that installation of a hoisting machine is easier and cheaper than when installing the hoisting machine into the top part of a building. Yet another advantage is faster and easier installation of an elevator, because the ^' dimensional accuracy requirements for the alignments of the traction sheaves and diverting pulleys are lower. Another advantage is also that suitably dimensioned traction members function as compensating ropes, in which case separate compensating ropes are not needed. In this case the masses to be moved as well as the costs of the elevator are smaller. Additionally another advantage is that the tensioning devices of the traction members function as compensating weights, and this also lowers the costs of the elevator. In addition, in a toothed belt drive the machine of the elevator functions as a locking device, in which case a separate locking device is not needed. All in all, the arrangement according to the invention enables much smaller moving masses than in elevators according to prior art, in which case the acceleration power needed is smaller, a consequence of which is a smaller machine, a more lightweight structure, smaller guide rails, smaller guide rail clamps, et cetera. In addition, the diameter of the traction sheave can be approx. 1/4 of the diameter of the traction sheave needed in solutions according to prior art. From this it follows that a sufficient torque of the machine is also only approx. 1/4 of the torque needed in solutions according to prior art. In this case the efficiency ratio of the machine is appreciably better than prior art, because the speed of rotation is approx. four times faster. Another advantage is that the shaft load of the hoisting machine of the elevator is only a fraction of the shaft load of solutions according to prior art, because the shaft of the machine does not support hanging masses, but instead only the active forces produced by traction. In this case the dimensioning of the bearings can be a lot lighter. Additionally, since the suspension ropes do not participate in the traction, the dimensioning of them can be made to be more lightweight, in which case thinner ropes or fewer ropes can be used. Likewise the structures and peripherals of the elevator are in this case lighter and cheaper. Yet another advantage is that the same elevator concept can be used for different applications, e.g. for residential apartment use or hotel use, and the use of the elevator can be monitored after the original installation and, based on the results, the balance of the elevator can easily be changed to correspond better to the actual use of the elevator.

In the following, the invention will be described in more detail by the aid of some examples of its embodiment with reference to the simplified and diagrammatic drawings attached, wherein

Fig. 1 presents an oblique sectioned view from the top and side of a traction member according to the invention,

Fig. 1 a presents an oblique sectioned view from the top and side of one second traction member according to the invention,

Fig. 1 b presents an oblique sectioned view from the top and side of one third traction member according to the invention, c presents an oblique sectioned view from the top and side of one more traction member according to the invention,

presents a simplified and diagrammatic side view of one elevator arrangement according to the invention, wherein the hoisting machine of the elevator is disposed in the bottom part of the elevator hoistway, or close to it,

presents a simplified and diagrammatic top view of one elevator arrangement according to Fig. 2, wherein the compensating weights are disposed on different sides of the guide rail line of the elevator car to each other and on different sides of the elevator car,

presents a simplified and diagrammatic top view of one elevator arrangement according to Fig. 2, wherein the compensating weights are disposed on the same side of the guide rail line of the elevator car as each other and on different sides of the elevator car,

presents a simplified and diagrammatic side view of one second elevator arrangement according to the invention, wherein the hoisting machine of the elevator is disposed in the bottom part of the elevator hoistway, or close to it,

presents a simplified top view of an elevator arrangement according to Fig. 5, in the bottom part of the elevator hoistway,

presents a simplified and diagrammatic side view of one third elevator arrangement according to the invention, wherein the hoisting machine of the elevator is disposed in the bottom part of the elevator hoistway, or close to it,

presents a simplified top view of an elevator arrangement according to Fig. 7, in the bottom part of the elevator hoistway, and Fig. 9 presents a simplified and diagrammatic front view of yet one more elevator arrangement according to ■ ^■ - the invention, wherein two hoisting machines of the elevator are disposed in the bottom part of. the hoistway, or close to it.

As already mentioned above, a flexible belt, e.g. provided with thin tension means, gives easily and flexes with respect to errors in the planes of rotation between the traction sheaves and the diverting pulleys. However in belt drives in which the lengths of the belt are long, such as e.g. in elevator use, in which a belt is used as a traction member, an easily elongated belt causes many problems and therefore elongations must be minimized. In this case reinforcements must be used that are more rigid than normal, but a problem arising in these cases is that the tooth shapes must be very precise and the alignment accuracy of traction sheaves and diverting pulleys must be extremely good, because otherwise the difference between the tension of the center part of the belt and the tension exerted on the edges becomes too large, which then wears the belt.

Table 1 below presents the main properties and the distribution of tensions and forces exerted on the teeth in relation to the width of the belt at a certain load of the belt and with an alignment error of 0.5 mm/100 mm between the planes of rotation of the traction sheaves and diverting pulleys of a standard toothed belt according to prior art provided with relatively thin and flexible reinforcements of equal thickness as each other. The values presented in Table 1, as also in the corresponding Tables presented later, are for only one side of the width of the toothed belt such that Reinforcement no. 1 is the closest stiffener, i.e. tension means, to the longitudinal center line of the toothed belt, Reinforcement no. 2 is the next reinforcement towards the edge of the toothed belt and Reinforcement no. 9 or 10 is the edgemost reinforcement of all. Thus the toothed belt presented by Table 1 comprises altogether 20 longitudinal reinforcements of the toothed belt, 10 units of which are on each side of the longitudinal center line of the toothed belt. The second column presents the diameter (d) of the tension means functioning as a reinforcement, the third presents the modulus of elasticity (E) of the reinforcement, the fourth the tension (F) produced in the reinforcement. The fifth column presents the elongation (s) produced in the reinforcements, and the last column presents as a percentage the relative tension F% acting on the reinforcements when Reinforcement 1, being the reference, is 100%. The last column thus presents the percentage tension distribution acting on the teeth over the width of the toothed belt.

Table 1

From Table 1 it is seen that the tension produced in the belt and in the teeth of the belt is clearly greater on the edges of the belt than in the center of the belt. The value of 100% in the center corresponds to a value of 121.4% on the edges of the belt .

If a belt provided with thin reinforcement is too flexible e.g. to be a long traction belt, it is easy to stiffen the belt e.g. by increasing the diameters of the reinforcements. Table 2 presents an example implemented with otherwise the same values as in Table 1, except that . the diameter of the reinforcements is now 2.0 mm instead of 1.2 mm.

Table 2

From Table 2 it is seen that the elongations (s) of the belt provided with thicker reinforcements are smaller with the same forces than the elongations of the belt presented in Table 1, i.e. the belt is now more rigid. But the problem now is that the tension distribution between the center part and the edges of the belt has grown considerably. The value of 100% in the center now corresponds to a value of 157.0% on the edges of the belt. This difference produces great stress on the teeth of the belt, if the imprecision of the alignment of the alignment of the planes of rotation is in the example the aforementioned 0.5 mm/100 mm. In other words the dimensional accuracy should be improved if a smaller stress distribution is to be achieved. Improvement of the measurement accuracy is not, however, very easy.

A solution to the problem in the traction member arrangement according to the invention is that the rigidity of the tension means that are the reinforcements is configured to decrease from the center of the belt going towards the edges. In this case in the proximity of the edges of the belt there are thus more flexible tension means than in the proximity of the center line of the belt. This type of structure can be implemented in many different ways, e.g. by disposing in the proximity of the center line of the belt reinforcements that are larger in diameter than in the proximity of the edges of the belt and the effect can be further improved by using thinner reinforcements the nearer the edge of the belt the reinforcement is situated.

Table 3 presents one aforementioned embodiment comprising a total of 18 reinforcements possessing the same tensile strength and modulus of elasticity.

Table 3

From Table 3 it is seen that now the stress distribution does not increase evenly when going towards the edges of the belt, but the distribution is now, however, significantly more even than in the example according to Table 2, although the reinforcements used in the center of the belt are even thicker than the reinforcements presented in Table 2. The stress distribution increases at first in the centermost reinforcements from an even value of 100% to a value of 120.9%, until it drops in the thinner reinforcements more toward the edge to a value of 100.8%, to finally increase in the edgemost reinforcements to a value of 120.9%. Owing to the smaller stress distribution this solution allows a much larger dimensional inaccuracy in relation to the planes of rotation between the traction sheaves and the diverting pulleys . Another way of configuring the rigidity of the tension means to decrease when going from the center of the belt towards the edges is to dispose reinforcements having - a larger tensile strength and modulus of elasticity in the center of the belt and reinforcements having a smaller tensile strength and modulus of elasticity in the edges. This can be implemented e.g. with different braids and with different materials of the reinforcements. Table 4 presents one aforementioned embodiment comprising a total of 18 reinforcements of the same thickness.

Table 4 From Table 4 it is seen that now the stress distribution does not increase evenly when going towards the edges of the belt, but the distribution is now, however, significantly more even than in the example according to Table 2, although the reinforcements used are even thicker than the reinforcements presented in Table 2. The stress distribution increases at first in the centermost reinforcements possessing a larger modulus of elasticity from an even value of 100% to a value of 121.1%, until it drops in the thinner reinforcements possessing a smaller modulus of elasticity that are more toward the edges to a value of 102.5%, to finally increase in the edgemost reinforcements to a value of 124.9%. Owing to the smaller stress distribution this solution also allows a much larger dimensional inaccuracy in relation to the planes of rotation between the traction sheaves and the diverting pulleys than the solution according to prior art presented in Fig. 2. When using the traction members presented by the traction member arrangement according to the invention, the tensions in relation to the width of the toothed belt are more even than in toothed belts according to prior art. In this case the tension arising is transmitted as a more even force to the teeth and the contact force between the traction sheave or diverting pulley and a tooth is transmitted evenly over the whole width of the tooth, in which case large local forces are not exerted on the tooth and the tooth wears evenly. In the solution according to the invention the teeth of the belt are easily able to directly reach the toothed surfaces of the traction sheaves or diverting pulleys also when the pulley/sheave is near the fixing point of the toothed belt, e.g. in elevator use when the elevator car or compensating weights come close to the diverting pulleys in the bottom part of the hoistway. Since the force caused by the tension difference is smaller than in solutions according to prior art, the toothed belt does not need to be as rigid as in solutions according to prior art and the belt can manage to bend in a slewed direction more than belts according to prior art. In this case also the back part of the belt can be made to be thinner than normal.

Figs. 1-lc present a simplified cross-sectional view of some belts belonging to the traction member arrangement according to the invention. Fig. 1 presents a toothed belt 1 provided with straight teeth lc, inside the back part Id in the shell of which is a plurality of tension means 7 functioning as reinforcements. The tension means 7 are side by side at regular intervals from each other in the back part Id and they are arranged essentially on a plane in the direction of the plane of the back part Id of the toothed belt 1. In the solution according to Fig. 1 all the tension means 7 are of the same material as each other and they have essentially the same tensile strength and modulus of elasticity as each other. Instead, the tension means 7a that are in the center of the back part Id of the toothed belt 1 are larger in diameter than the tension means 7b and 7c that are on the edges of the back part Id, of which tension means the edgemost 7c are the smallest of all in diameter. Since the tension means 7a-7c are of the same material and they have essentially the same tensile strength and modulus of elasticity as each other, the thicker tension means 7a in the center are more rigid than the thinner tension means 7b and 7c on the edges. From this it follows that the toothed belt 1 can elongate at its edges more than at its center part, in which case the toothed belt 1 is more flexible at its edges than at its center part. This property helps the teeth lc to adapt better to angular differences in the planes of rotation of the traction sheaves and diverting pulleys, in which case the structure is more forgiving to dimensional errors occurring in installation in the alignment of traction sheaves- and diverting pulleys.

Fig. la presents a toothed belt 1 otherwise of the type of Fig. 1 but in this solution greater flexibility of the edges of the back part Id than of its center part is implemented in the manner presented in Table 4. In this case all the tension means 7 are as thick as each other, but the tensile strength and the modulus of elasticity of the tension means 7d that are in the proximity of the longitudinal center line of the toothed belt 1 are greater than the tensile strength and the modulus of elasticity of the tension means 7e that are in the proximity of the side edges of the toothed belt 1. Since the tension means 7d near the center line have greater tensile strength and a greater modulus of elasticity than the tension means 7e in the proximity of the edges, the tension means 7d in the center are more rigid than the tension means 7e on the edges. From this it follows that the toothed belt 1 can elongate at its edges more than at its center part, in which case the toothed belt 1 is more flexible at its edges than at its center part, and the structure is more forgiving to dimensional errors occurring in installation in the alignment of traction sheaves and diverting pulleys than solutions according to prior art .

Figs, lb and lc present a toothed belt 1 otherwise of the type of Fig. 1, but in these solutions the toothed belt 1 is provided with teeth lc that are at an inclined attitude with respect to the direction of travel of the toothed belt 1, instead of with straight teeth at a right angle with respect to the direction of travel of the toothed belt 1. With these shapings of the tooth the stress exerted on the teeth lc is reduced such that, owing to the angled shape, the surface pressure in the mesh is smaller than the corresponding surface pressure of a straight tooth.

In the toothed belt 1 presented in Fig. lb, the teeth lc are, as viewed from above, the shape of an open V, in which the tip of the tooth is on the longitudinal center line of the toothed belt 1. Correspondingly, in the toothed belt 1 presented in Fig. lc, the teeth lc are, as viewed from _, above, again the shape of an open V, but now the tip part is missing from the teeth and the teeth on each side of the longitudinal center line of the toothed belt 1 are separate from one another such that a straight groove le in the longitudinal direction of the toothed belt 1, extending to the front surface of the back part Id of the tooth, forms in the longitudinal center line of the toothed belt 1.

For adjusting the rigidity between the center part and the edge parts of the toothed belt 1, the number, size, strength properties, braiding, material and locations of the tension means 7 of the back part Id of the toothed belt 1 can be varied in many different ways. The rigidity of the edge parts can be further reduced e.g. by increasing the distance between tension means 7 in the proximity of the edges of the toothed belt 1.

One possibility in the traction member arrangement according to the invention, as is already mentioned above, is to increase the diameter of the tension means 7 compared to the tension means in corresponding belts according to prior art. In this way more load-bearing cross-sectional area of reinforcement, e.g. steel cross-sectional area, is easily obtained. For example, increasing the diameter of the tension means 7 from a diameter of 1.6 mm to a diameter of 2.25 mm doubles the load-bearing cross-sectional area. In this case a steel of a lower strength grade, which is also cheaper, can correspondingly be used as the material of the tension means 7. Generally steel wires that are less strong are also less brittle, in which case tension means 7 made from steel of a lower strength grade are less vulnerable to damage. When using wires of strength e.g. 1770 N/mm ² instead of wires of strength 2350N/mm ² and when increasing the diameter of the tension means 7 such that their cross-sectional area doubles, the strength of the tension means 7 increases by a factor of 1.5.

To enable the arrangement according to the invention, at least one elevator arrangement comprises at least an elevator car 11 configured to move up and down in an elevator hoistway and at least one or more compensating weights 2a, 2b, which are for their part connected to support the elevator car 11 by the aid of their own suspension members 3 that are completely separate from the traction members 1, la, lb, such as by the aid of belts or ropes and also by the aid of e.g. diverting pulleys 4 mounted on bearings in the top part of the elevator hoistway. In addition, the arrangement according to the invention comprises a hoisting machine 6 provided with at least one traction sheave 5 or corresponding, and at least two or more traction members la, lb, such as a rope or a belt, which are configured to transmit the rotational movement of the traction sheave 5 into linear movement of the elevator car 11 and of the compensating weights 2a, 2b. Characteristic to the invention, and common to all the different embodiments of the invention, is that each compensating weight 2a, 2b, or in some cases only one, or more than two, compensating weights, are connected by the aid of their own traction member la, lb provided with essentially constant tensioning to most preferably one and the same hoisting machine 6. If there is only one compensating weight, for safety reasons there are nevertheless at least two traction members 1, la, lb so, that when one traction member loses its grip, the other one still grips and the elevator car 11 is not able to rush to the roof with a small load pulled by the compensating weight.

The aforementioned two or more compensating weights 2a, 2b enable an essentially easy layout in elevator design. At the same time the layout also brings various space benefits. In this case one layout solution can be e.g. the type of layout in which, when viewed from above, at the center of the elevator hoistway is a plane formed by the car guide rails of the elevator and around this plane are four corners for different structural solutions. For example, two corners are used for the compensating weights 2a, 2b and their guide rails, one corner is used for safety devices, mainly e.g. for an overspeed governor, and one corner is used for other devices, such as for the trailing cables, et cetera. From the viewpoint of the layout, it is advantageous to situate the compensating weights 2a, 2b, with their guide rails, in the rear corners of the elevator hoistway.

Fig. 2 presents a simplified and diagrammatic side view of one elevator arrangement according to the invention. The elevator arrangement according to Fig. 2 comprises two compensating weights 2a and 2b, both of which are connected to the elevator car 11 by the aid of their own suspension members 3. Each suspension member 3 is fixed at its first end to the elevator car 11 and passes over a diverting pulley 4 in the top part of the elevator hoistway or in the machine room and returns downwards, and is fixed at its second end to a compensating weight functioning as a counterweight 2a, 2b. The suspension members 3 are preferably so-called "high tensile rope" type members, having a strength category of over 2100 N/mm2. The fixing point of the first end of the suspension member 3 to the elevator car 11 is configured such that the elevator car 11 can rise past the diverting pulleys 4 in the top end of the ho.istway right to the top end of the hoistway. In this way the most space-efficient layout solution possible is achieved. All the elevator arrangements according to the invention can comprise the same type of fixing solution of the suspension member 3 to the elevator car 11, although that is not presented in all the figures.

A hoisting machine 6 provided with a traction sheave 5 is configured to move the elevator car, which hoisting machine is preferably disposed in the bottom part of the elevator hoistway, e.g. on the base of the elevator hoistway or right in the proximity of the base. In this case installation of the hoisting machine 6 is easy, and long electric cables from the bottom part of the building to the hoisting machine or to the cubicles are not needed. Additionally, at least one humidity sensor, which is arranged to issue an alarm and if necessary to stop the elevator if excessive water comes onto the base of the hoistway, is disposed on the base of the hoistway. In this way the elevator machine and the electrical components of the elevator can be protected from excessive humidity.

For each compensating weight separately its own traction member la, lb is disposed between the bottom part of the compensating weights 2a, 2b and the bottom part of the elevator car 11, which traction member receives its movement transmission force from the traction sheave 5 of the hoisting machine 6. The first traction member la is fixed at its first end to a first compensating weight 2a, is configured to leave the compensating weight 2a and go downwards and is led to pass under at least one diverting pulley 8a, after which the traction member la is led to a traction sheave 5, which rotates on the vertical plane, of the hoisting machine 6 disposed below the elevator car 11 from the first side of the traction sheave 5, and is configured to pass around the traction sheave 5 on a first point of the contact surface of the traction sheave 5 on the second side of the traction sheave 5, to return back to the first side of the traction sheave 5 and is led onwards to pass under at least a second diverting pulley 8b and to ascend after this to the elevator car 11, on which is a fixing means 11a maintaining essentially constant tensioning force, to which the traction member la is fixed at its second end.

The second traction member lb is configured to travel from the second compensating weight 2b via the traction sheave 5 to the elevator car in essentially the same manner as the first traction member la. In this case the second traction member lb is fixed at its first end to a second compensating weight 2b, is configured to leave the compensating weight 2b and go downwards and is led to pass under at least one diverting pulley 9a, after which the traction member lb is led to a traction sheave 5, which rotates on the vertical plane, of the hoisting machine 11 disposed below the elevator car 11 from the second side of the traction sheave 5, and is configured to pass around the traction sheave 5 on a second point of the contact surface of the traction sheave 5 on the first side of the traction sheave 5, to return back to the second side of the traction sheave 5 and is led onwards to pass under at least a second diverting pulley 9b and to ascend after this to the elevator car 11, on which is a fixing means lib maintaining essentially constant tensioning force, to which the traction member lb is fixed at its second end. The contact surface of the traction sheave 5 is so wide that both the traction members la, lb fit side-by-side onto the contact surface of the traction sheave without- interfering with each other. In this way one and the same hoisting machine 6 gives to both the traction members la, lb a force producing linear movement of the elevator car 11 and of the compensating weights 2a, 2b.

Figs. 3 and 4 present top views of different options for disposing the compensating weights 2a, 2b in the elevator hoistway. In Fig. 3 the compensating weights 2a, 2b are disposed on opposite sides of the elevator car 11 and on different sides of the guide rail line of the elevator car 11 to each other, in which case the suspension of the elevator car 11 and of the compensating weights 2a, 2b is very symmetrical and does not produce any additional stresses e.g. on the guide rails. This is an extremely advantageous layout option if it is only possible. Correspondingly, in Fig. 4 the compensating weights 2a, 2b are disposed on opposite sides of the elevator car 11 and on the same side of the guide rail line of the elevator car 11 as each other. In this case the reason has been e.g. some issue relating to layout, owing to which the space on the other side of the guide rail has been reserved for some other use than the use of compensating weights. In this solution also, however, it is possible to ^' implement suspension that is as symmetrical as possible and that does not produce additional stresses e.g. on the guide rails. Figs. 5 and 6 present a simplified and diagrammatic view of one second elevator arrangement according to the invention, wherein the hoisting machine 6 of the elevator is disposed in the bottom part of the elevator hoistway, or close to it. Fig. 5 presents the solution as viewed from the side, and Fig. 6 the same solution as viewed from the top of the hoisting machine 6. For the sake of clarity the compensating weights 2a, 2b are presented in Fig. 6 with dot-and-dash lines .

In the arrangement according to Figs. 5 and 6 the traction members la and lb are led to circulate from the compensating weights 2b and 2a to the elevator car in essentially the same manner as in the arrangement according to Fig. 2. The difference now, however, is that the hoisting machine 6 has been turned into such an attitude that the shaft of it is essentially vertical, in which case the plane of rotation of the traction sheave 5 is essentially on the horizontal plane. In this way a very shallow machine solution is achieved, which reduces the space requirement in the bottom part of the hoistway and enables driving of the elevator car to as far down as possible. The contact surface of the traction sheave 5 is, however, so wide that both the traction members la, lb fit side-by-side onto the contact surface of the traction sheave without interfering with each other. Figs. 7 and 8 present a simplified and diagrammatic view of one more elevator arrangement according to the invention, wherein the hoisting machine 6 of the elevator is disposed in the bottom part of the elevator hoistway, or close to it. Fig. 7 presents the solution as viewed from the side, and Fig. 8 the same solution as viewed from the top of the hoisting machine 6. For the sake of clarity the compensating weights 2a, 2b are presented in Fig. lb with dot-and-dash lines . In the arrangement according to Figs. 7 and 8 the traction members la and lb are led to pass from the compensating weights 2a and 2b to fixing means 11a, lib disposed in connection with the elevator car 11 directly via the traction sheaves 5, which traction sheaves 5 are connected to a hoisting machine 6 via a shaft 6a. In the arrangement according to Figs. 7 and 8 the traction sheaves 5 with their shafts 6a rotate in different directions to each other, but the arrangement can be implemented also such that both the traction sheaves 5 rotate in the same direction. From Fig. 8 it is seen that the hoisting machine 6 and its shaft 6a are at some certain angle with respect to the compensating weights 2a, 2b and their guide rail line. This angle can, however, vary, depending on the respective elevator layout solution. In this way a very shallow and simple machine solution is achieved without diverting pulleys in the bottom part of the hoistway, which solution reduces the space requirement in the bottom part of the hoistway and enables driving of the elevator car to as far down as possible.

Fig. 9 presents a front view of one more elevator arrangement according to the invention, comprising two hoisting machines 6 of the elevator, which, with the traction sheaves 5, are disposed in the bottom part of the elevator hoistway, or close to it. The first hoisting machine 6 is fitted between one or more compensating weights 2 and the elevator car 11 on one side of the elevator car 11, and the second hoisting machine 6 is fitted between one or more compensating weights

2 and the elevator car 11 on a second side of the elevator car 11. This solution enables the base of the elevator hoistway to be made level, particularly in its center part, and the hoisting mechanics can be made simple.

According to the arrangements of Figs. 1-9, the traction member 1, la, lb is preferably a toothed belt. What all the arrangements presented have in common is that the traction members 1, la, lb are fixed at one of their ends, e.g. their end on the elevator car 11 side, with a fixing means 11a, lib providing a constant tensioning force such that the traction member 1, la, lb always remains sufficiently taut on the rim of the traction sheave 5 and that when the suspension members

3 of the elevator car 11 stretch and loosen the fixing means 11a, lib remove the elongation produced via the traction members 1, la, lb. The tensioning force is arranged with a spring, electrically, hydraulically or pneumatically such that the magnitude of the constant tensioning force to be maintained is preferably at least (g+a) *H*m _belt , where a = downward deceleration of an emergency stop, ^" H = travel height and m _be i _t = weight per meter of the traction members 1, la, lb. The fixing means 11a, lib is additionally provided with an overload function, which limits the tensioning force of the traction member 1, la, lb to the desired maximum value, which is preferably greater than the force exerted on the fixing means 11a, lib in an emergency stop of the empty elevator car 11.

In the elevator solution according to the invention the supporting of the elevator car 11 is separated from the moving means of the elevator car and smart materials, such as toothed belts, in which traction is not based on friction but instead on shape-locking, preferably suited to the purpose are used as the moving means, i.e. as the traction members 1, la, lb. Since the traction is not based on friction and elongations of the suspension members 3 can. easily be compensated with the fixing means 11, 11a, lib according to the invention that provide the traction members 1, la, lb with a constant tensioning force, one or more compensating weights 2, 2a, 2b can be used instead of counterweights, which compensating weights are disposed in the elevator hoistway space-efficiently in relation to the cross-section of the elevator hoistway and their mass is optimized according to the use of the elevator such that the elevator arrangement is made to function in the best possible way in relation to energy efficiency in exactly the use for which it has been delivered. By proceeding in this manner the use of a new or modernized elevator is monitored initially after installation of the elevator and according to the monitoring results the balancing is adjusted e.g. within such limits that the aggregate mass of the compensating weights 2-2b is some suitable value between -10...60% of the rated load of the elevator, preferably e.g. some suitable value between 0...50% of the rated load of the elevator. The aforementioned space efficiency can be further improved with traction sheaves and diverting pulleys that are small in diameter and that can be disposed in a ^' small space. In the elevator solutions presented by Figs. 2-9, a trailing cable 10 is fixed from the elevator car 11 to the wall of the elevator hoistway, the weight per meter of which trailing cable (m _cab i _e ) is the difference (m _rope - m _be it) between the metric weights of approx .4 *the suspension members 3 and of the traction members 1, la, lb. Correspondingly, the mass (BWT) of the compensating weights 2a, 2b is preferably determined such that it is the mass (KT) of the elevator car 11 and its auxiliary devices + balance percentage (C%) *load (Q) + travel height (H) *the difference between the weights per meter of the suspension members and the traction members (m _rop e - m _belt ) . In other words:

The mass of the trailing cable can be determined as follows: liable = 4* (m _rope - m _be i _t )

Correspondingly, the mass of the compensating weights can be determined as follows: BWT = KT+C%*Q+H* (m _rope - m _belt )

With these definitions the advantage is achieved that the elevator is in balance and separate compensating ropes are not needed.

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When using the arrangement according to the invention in elevator solutions, as described above, such that the supporting and the moving of the elevator car 11 are separated from each other, the suspension members 3 of the elevator can be optimized such that the safety factor is only the 12 conventionally demanded in safety norms, or a little more, depending on the groove profiles of the diverting pulleys suspending the suspension members 3. In traction sheave elevators, in which the ropes support and transmit the driving force, the safety factor can easily in practice be implemented 30% or even over 50% higher than the 12 according to the minimum requirement, which results from other dimensioning criteria affecting the ropes, e.g. from endurance to maximum surface pressure, et cetera. An elevator based on the arrangement according to the invention thus also becomes lighter owing to the lightening of the roping.

It should also be noted that the different solutions presented above can be inventive features together with one or more other features of the invention. It is obvious to the person skilled in the art that the invention is not limited solely to the examples described above, but that it may be varied within the scope of the claims presented below. Thus, for example, the suspension solutions can be different to what is presented above.

It is also obvious to the skilled person that the location of the hoisting machine can be elsewhere than what is presented above in the drawings. The hoisting machine can be on the base of the elevator hoistway, or close to the base, but also on some side of the elevator hoistway and also in the top part of the elevator hoistway.

It is further obvious to the person skilled in the art that the number of compensating weights can also be greater than two or three. There can be e.g. four, six, eight, ten or even more compensating weights disposed in a different manner.

It is also obvious to the person skilled in the art that the structure and shape of the belts functioning as the traction members can differ to what is presented above. Thus, for example, the attitude and shape of a tooth can be different to what is presented above and the structure, shape, size, number, location, strength and material of the tension means in the back part of the belt can be different to what is presented above. Thus, for example, it is obvious to the skilled person that the material of the tension means, especially on the edges of the belt, can instead of steel be e.g. carbon fiber, glass fiber, an artificial substance, preferably^ Aramid, or combinations of one or more of the aforementioned or some other material or non-metal fiber or braid suited to the purpose .

It is also obvious to the skilled person that the edges of belts functioning as traction members can be arranged to be more flexible than the center part by completely omitting the tension means from the edge of the belt for a suitable distance towards the center line of the belt. In this way the tensile strength and elongation of the belt are based at the edges of the belt on only the own basic material of the belt, which can however be stronger material than the center part of the belt .

It is also obvious to the person skilled in the art that instead of a toothed belt the traction member can also be e.g. a multigroove V-belt, a plurality of parallel hoisting ropes or even a chain-type member.