This application is a continuation of PCT/FI2007/000088 filed on Apr. 10, 2007, which is an international application claiming priority from FI 20060348 filed Apr. 10, 2006, the entire contents of which are hereby incorporated by reference.
The present invention relates to an arrangement as defined in the preamble of claim 1 for equalizing the rope force of an elevator. The invention also relates to an elevator as defined in the preamble of claim 10.
It is becoming increasingly common to use large suspension ratios, e.g. 3:1 . . . 9:1 and even larger, in traction sheave elevators. This generally involves the problem that, due to the many rope loops used, hoisting ropes of great length are required. For the operation and safety of the elevator, it is essential that the hoisting rope portion of the hoisting ropes below the elevator car be kept sufficiently tightly tensioned, and thus the amount of rope elongation to be compensated, or equalized, is also large. Due to the length of the adjustment distance, it is difficult to implement the required rope compensation sufficiently effectively using prior-art rope compensation devices.
Another reason requiring long ropes may be a large hoisting height of the elevator. In this case, the length of the hoisting ropes used in the elevators is also large, and therefore elevators having a large hoisting height also require a compensation arrangement capable of compensating a large elongation. In such structures, large elongations produce problems already starting from 1:1 suspension.
The construction and quality of the materials used in elevator technology as well as the control and operating systems have improved so much that nowadays it is increasingly commonly possible to implement traction sheave elevators without using a counterweight at all. In these elevator solutions, proper and reliably functioning equalization of rope forces is very important.
The rope force equalizing solutions used in prior art include solutions in which the equalization is based on various spring and lever systems. These solutions use e.g. spring or lever systems with either end of the hoisting ropes secured to them. However, a problem with such solutions is the required length of adjustment distance, because the substantially short displacement of the spring or lever does not allow a large adjustment distance and consequently does not permit compensation of large elongations. This involves at least the problem that, in the case of large suspension ratios or when long hoisting ropes are otherwise used in tall buildings, equalization of rope forces is not possible because of the length of the adjustment distance.
A better solution for equalization in cases of a long distance to be compensated would be a compensating sheave, the rim of which allows a longer compensation distance for a hoisting rope fastened to the rim than the displacement of a spring or lever. As is known, such compensating sheaves have been used for this purpose, but they also involve certain problems. One of the problems is e.g. the fact that, due to its size, the fastening of the end of the hoisting rope on the compensating sheave takes up a large space. Therefore, a compensating sheave with the hoisting rope ends fastened to it in the traditional manner according to generally known technology would have to be of a very large size to allow the elements required for the fastening to be placed on the compensating sheave. This would lead to the problem of having a complicated, large and heavy compensating sheave that is difficult to dispose in a suitable place in conjunction with other structures of the elevator. Additionally, even when compensating sheaves are used, the adjustment distance is relatively short, and thus no very large elongations can be compensated.
International patent specification no. WO2004/067429 discloses several solutions for the compensation of rope elongations. Of these solutions, especially the described block and tackle arrangements work otherwise well except that they are primarily only suited to be placed in the shaft, separately from the car.
The object of the present invention is to overcome the above-mentioned drawbacks and to achieve a reliable, simple, economical and effective arrangement for equalizing rope forces in an elevator, an arrangement that is easy to install and enables even large elongations to be compensated. The arrangement of the invention is characterized by what is presented in the characterization part of claim 1. The elevator of the invention is characterized by what is presented in the characterization part of claim 10. Other embodiments of the invention are correspondingly characterized by what is disclosed in the other claims.
Inventive embodiments are also presented in the description part of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims below. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of explicit or implicit sub-tasks or with respect to advantages or sets of advantages achieved. In this case, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts. Similarly, features described in connection with each embodiment example of the invention can be applied in conjunction with other embodiments as well.
The solution of the invention has the advantage of being simple, economical, clear, versatile and effective in structure. A further advantage is that its structure allows the compensating device of the invention to be implemented as a compact component that can be placed in a small space and is thus easy to dispose in a suitable place in conjunction with other structures of the elevator, depending on the rope transmission. An additional advantage is that, when the compensating device of the invention is used, an adjustment distance of several turns can be easily provided at the end of the hoisting ropes, which allows even very large rope elongations to be compensated, so that it is possible to build elevators without counterweight having long hoisting ropes and therefore also large rope elongations or rope springing. By varying the magnitude and mutual ratio of the diameters of the transmission pulleys of the compensating device, it is possible to adjust the magnitude of the rope elongation to be compensated and the ratio between the rope forces acting on the traction sheave that can be standardized by the arrangement in question. Yet another advantage is that the suspension points can be easily disposed in a desired place and the suspension can be implemented e.g. in a centered manner as seen from above the elevator car, without any special extra functions. This is very important e.g. in the case of 1:1 suspension.
In the following, the invention will be described in detail by referring to two different embodiment examples and the attached drawings, wherein
In the solution according to
From the traction sheave 6 the hoisting ropes are passed downwards to the lower part of the elevator shaft, where the hoisting ropes pass under a diverting pulley 8 mounted in the lower part of the elevator shaft. From here, the hoisting ropes 3 are passed upwards over a diverting pulley 9 secured to the lower part of the car frame 2 and then further under a second diverting pulley 10 mounted in the lower part of the elevator shaft. From diverting pulley 10 the hoisting ropes 3 are passed to a reel secured to the lower part of the car frame 2 and serving as a regulating element 11, around which a desired number of turns of the end portions of the hoisting ropes 3 are wound, after which the second end of the ropes is secured to the reel 11. To obtain a sufficiently long adjustment distance, the number of turns is at least more than one.
Compensation of the hoisting ropes 3 is implemented using a rope force compensating device 20 disposed in conjunction with the elevator car 1, said device comprising at least a first or upper tensioning device 21 and a second or lower tensioning device 22, which in the example in
The rope forces remain equalized and the hoisting ropes are kept tight as the tensioning devices 21 and 22 are rotating in a mutual relation determined by the transmission ratio, and the compensating device 20 simultaneously adjusts the length of hoisting ropes 3 wound around the reels at each instant. The length of hoisting ropes 3 wound around the reels 11 and 14 determines the amount of adjustment tolerance available.
In this solution, the first end of the hoisting rope portion 3 above the elevator car is secured to a fixed anchorage 23 in the upper part of the car frame 2, from where the hoisting ropes 3 are passed e.g. over a diverting pulley 12 to the traction sheave 6 of the hoisting machine 5, which is mounted in the upper part of the elevator shaft. The hoisting ropes 3 are arranged to pass over the traction sheave 6 and further under a diverting pulley 7 placed in conjunction with the hoisting machine 5 and functioning as a counterpulley, and once more over the traction sheave 6. After this, the hoisting ropes 3 are passed to the counterweight 19, where the second end of the hoisting rope portion above the elevator car is secured to the reel of the upper tensioning device 21 of the compensating device 20 fitted in the upper part of the counterweight 19, in a manner corresponding to the solution according to
Similarly, the first end of the hoisting rope portion 3 below the elevator car is secured to the reel of the lower tensioning device 22 of the compensating device 20 fitted in the lower part of the counterweight 19, in a manner corresponding to the solution of
In the situation illustrated in
It is obvious to a person skilled in the art that different embodiments of the invention are not exclusively limited to the examples described above, but that they can be varied within the scope of the claims presented below. Thus, for example, the structure of the compensating device may vary. For example, instead of a belt, some other appropriate transmission means, such as e.g. a rope, chain or a corresponding force transmission means can be used to connect the tensioning devices. The force can also be transmitted between the tensioning devices by toothed engagement.
It is also obvious to a person skilled in the art that the invention can just as well be used with other suspension ratios and in other types of suspension besides those described in the example. For example, the number and disposal of diverting pulleys can be varied, and so can the placement of the compensating system. The compensating device may be placed e.g. in a fixed location in the elevator shaft. In practice, the compensating systems of elevators with even suspension ratios must be fixedly mounted in the elevator shaft, and the compensating systems of elevators with odd suspension ratios must be movable with the elevator car.
It is further obvious to a skilled person that the solution of the invention can also be implemented using other force ratios besides the 2:1 ratio described by way of example. The force ratio can be easily changed by altering the difference of size between the transmission pulleys.
It is additionally obvious to a skilled person that, although the 1:1 suspension described in the example comprises a small counterweight, which is primarily designed to control the rope dynamics, the invention can just as well be used in traction sheave elevators provided with a larger counterweight and also in traction sheave elevators having no counterweight at all.
It is further obvious to a skilled person that, depending on the solution, the transmission pulleys of the transmission means may also be placed side by side at substantially the same height, in which case, however, the hoisting ropes have to be somewhat longer than in the solution described above.
It is likewise obvious to a skilled person that the reels of the tensioning devices may be of mutually different diametric size, in which case the transmission ratio required for the force ratio is produced directly in the ratio between the diameters of the reels and no separate transmission pulleys are needed at all.
Number | Date | Country | Kind |
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20060348 | Apr 2006 | FI | national |
Number | Date | Country | |
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Parent | PCT/FI2007/000088 | Apr 2007 | US |
Child | 12230837 | US |