HK1100552B - Elevator pulley arrangement - Google Patents

Description

Elevator pulley device

Technical Field

The invention relates to an elevator having a car with a car frame on which are mounted a first set of diverting pulleys from which the hoisting ropes go downwards and a second set of diverting pulleys from which the hoisting ropes go upwards, in which elevator the rope tension in the rope portions going from the first set of diverting pulleys is smaller than the rope tension in the rope portions going from the second set of diverting pulleys in a prescribed ratio; and an arrangement in an elevator with a car frame, on which frame a first set of diverting pulleys is mounted from which the elevator hoisting ropes go downwards, and a second set of diverting pulleys from which the elevator hoisting ropes go upwards, said second set comprising at least one second diverting pulley, in which elevator the rope tension in the rope portions going from the diverting pulleys of the first set is smaller than the rope tension in the rope portions going from the diverting pulleys of the second set by a prescribed ratio.

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 resulted in, among other things, various elevator solutions without machine room. Elevators applying these solutions are fairly efficient in respect of space utilization, as they make it possible to eliminate the space requirement for the machine room in the building without enlarging the elevator shaft. In these basically good elevator solutions the space and placement of the hoisting function limits the freedom of choice in elevator lay-out solutions. The main limiting factor is the placement of the counterweight and the space it requires in the elevator shaft. Drum driven elevators, which are nowadays rather seldom installed, have the disadvantage that the hoisting machine is heavy and complicated and requires a lot of power and/or torque. It is known that prior art elevators without counterweight are extremely unstable and do not have a suitable solution. So far it has not been technically or economically reasonable to make elevators without counterweight. A similar solution is disclosed in specification WO 9801655. The recent international patent application PCT/FI 03/00818 discloses a feasible elevator solution without counterweight and using a large suspension ratio for suspending the car on the hoisting ropes, unlike the solutions of the prior art. Creating a traction sheave elevator without counterweight and with a number of rope portions of the hoisting ropes going downwards from the diverting pulleys of the car and rope portions going upwards from the diverting pulleys of the car is a challenging task in terms of roping and balancing of the car.

Disclosure of Invention

A general object of the present invention is to achieve at least one of the following various objects. It is an object of the invention to develop the elevator without machine room so as to achieve more efficient space utilization in the building and in the elevator shaft than before. This means that the elevator should allow installation in a relatively narrow elevator shaft if necessary. One object of the invention is to achieve an elevator in which the elevator hoisting ropes have a good grip/gripping action on the traction sheave. Another object of the invention is to create an elevator solution without counterweight without compromising on some of the characteristics of the elevator. It is also an object of the invention to achieve a more efficient use of the shaft space above and below the car than before also in the case of elevators without counterweight. While maintaining the possibility of running in the elevator shaft. A particular object is to create an elevator in which the car is suspended symmetrically on the hoisting ropes.

The aim or objects of the invention should be fulfilled without compromising the possibility of changing the basic lay-out of the elevator.

The elevator of the invention is characterized in that the diverting pulleys of the first set are at a larger average distance from the car frame than the diverting pulleys of the second set. The arrangement of the invention is characterized in that the distance of the second diverting pulley from the plane of the car frame is substantially smaller than the distance of the first diverting pulley from the plane of the car frame by the same prescribed proportion as the rope tension in the rope portion going from the first set of diverting pulleys is smaller than the rope tension in the rope portion going from the second set of diverting pulleys. Other embodiments of the invention are characterized by what is disclosed in the other claims. Embodiments of the invention are also presented in the description of the present application. The inventive content disclosed in the application can also be defined differently than is done in the claims below. The inventive content may also consist of several separate inventions, especially if the invention is considered as a sub-task, directly or implicitly or in respect of advantages or sets of advantages achieved. The various features of the different embodiments and applications of the invention may also be combined in other ways than those described herein. Some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts.

Elevators without counterweight allow the cross-sectional area of the shaft to be used efficiently and this efficiency can be increased by reducing the distance between the car wall and the shaft wall. With an advantageous roping solution the shaft space above and below the car can be reduced to a rather small scale. When high rope transmission ratios are used, the roping can advantageously be made symmetrical or nearly symmetrical with respect to the car, so that installation is not complicated.

On the car frame of the elevator of the invention are mounted diverting pulleys from which the hoisting ropes go downwards and diverting pulleys from which the hoisting ropes go upwards. The rope tension of the upper rope portion is greater than the rope tension of the lower rope portion. By placing the diverting pulleys of the lower rope portion at a larger average distance from the car frame than the diverting pulleys of the upper rope portion, the tilting moment acting on the car due to the tighter rope portions can be compensated unless the tilting moment can otherwise be conveniently dealt with by symmetrically arranging the diverting pulleys. By properly placing only one or two diverting pulleys it is possible to eliminate the tilting moment. A preferred method is to use an arrangement whereby the tilting moments generated by the diverting pulleys on the car frame cancel each other out.

With the present invention, one or more of the following advantages, among others, can be achieved:

the invention provides a simple method to achieve central suspension of the car of an elevator without counterweight;

in the elevator of the invention, a separate steel structure which can reduce the space of the shaft above the cage is not needed at the upper end of the elevator shaft;

at the lower end of the elevator shaft below the car, no space is needed for the diverting pulleys or other devices needed for suspension, so a shallow pit at the lower end of the elevator shaft will be sufficient;

in the elevator of the invention, no upward or downward rope portions, or diverting pulleys, are needed in the part directly above or below the car, and the shaft space needed above and below the elevator can be made shallower because the transverse travel of the hoisting ropes occurs in connection with the car.

By applying the invention, the cross section area of the shaft can be effectively utilized;

although the invention is primarily intended for elevators without machine room, it can also be used in elevators with machine room, in which case the hoisting ropes must be passed separately through the hoisting machine in the machine room or the traction sheave of the hoisting machine must be disposed to be mounted in the elevator shaft.

The optimum suspension ratio above and below the car is 2: 1, 6: 1, 10: 1, etc. Other suspension ratios may be used, such as 8: 1 or other even ratios. If in the rope suspension one end of the hoisting ropes is fastened to the car, the suspension ratio may be an odd ratio, such as 7: 1 or 9: 1.

Symmetrical suspension of the car relative to the car is easy to achieve at least in the preferred embodiments of the invention;

the installation and maintenance of the diverting pulleys of the elevator are easy to achieve since they are fastened in place by means of some fasteners.

An important area of application of the invention is elevators designed for transporting people and/or freight. The normal range of application of the invention is in elevators whose speed range is about or below 1.0m/s or may be higher. For example, an elevator traveling at a speed of 0.6m/s is easily implemented according to the present invention.

In the inventive elevator, normal elevator ropes, such as generally conventional steel wire ropes, can be applied. Elevators may employ ropes of synthetic material and rope structures with synthetic fiber load-bearing parts, such as so-called "aramid" ropes, which have recently been proposed for use in elevators. Also available are steel reinforced flat belts, especially because they can allow for smaller deflection radii. Particularly desirable for use in the elevator of the invention are elevator hoisting ropes twisted from e.g. round and strong wires. In this way it is possible to obtain thinner ropes and, due to the thinner ropes, smaller diverting pulleys and drive sheaves. For instance a strong 4mm filament rope may relatively preferably be twisted from the steel filaments so that the average wire thickness in the finished rope is between 0.15 and 0.25mm, wherein the finest steel filaments may have a thickness of only about 0.1 mm.

The elevator of the invention is a traction sheave elevator without counterweight and with a car guided by guide rails and suspended by means of diverting pulleys on a set of hoisting ropes in such a way that the set of hoisting ropes of the elevator comprises rope portions going upwards and downwards from the car. The elevator comprises a number of diverting pulleys in the upper and lower parts of the elevator shaft. The elevator has a drive machine provided with a traction sheave and placed in the elevator shaft. The elevator comprises a compensating device acting on the hoisting ropes to balance and/or compensate rope tension and/or rope elongation. The car has diverting pulleys mounted on it near both side walls. In the elevator of the invention the rope portions going from the traction sheave, from the diverting pulleys in the lower part of the elevator shaft and from the diverting pulleys in the upper part of the elevator shaft to the diverting pulleys mounted on the car run substantially vertically. In an elevator, the rope portions connecting the rope portions extending from one side of the car to the other are rope portions fitted between diverting pulleys near different side walls of the car.

Drawings

The invention will be described in detail hereinafter with reference to examples and the accompanying drawings, in which

Fig. 1 is a diagrammatic illustration of a car of an elevator applying the invention;

fig. 2 is a diagrammatic view illustrating the transmission of the elevator of the invention;

fig. 3 illustrates the car support frame of the present invention on the bottom of a shaft;

fig. 4 shows the car support frame of the invention extended to a height where the car can be mounted in the frame;

fig. 5 shows the car support frame of the invention in retracted form.

Detailed Description

Fig. 1 shows a car 1 with a car frame. In the figure, the car is shown in partial view. At the upper part of the car frame are placed diverting pulleys 9 mounted on the overhead beam to guide the ropes downwards and diverting pulleys 8 mounted on the overhead beam to guide the ropes upwards, said diverting pulleys belonging to a set of downwards-directed diverting pulleys 39 or a set of upwards-directed diverting pulleys 38, respectively. The upwardly and downwardly directed diverting pulleys on the overhead beams are fastened to the girders 10 of the overhead beams. The placement of the diverting pulleys on the corbel determines the lever arm from the plane of the car frame at or near which the elevator guide rails are located. On the other hand, a force proportional to the rope tension is transmitted to the car frame via the diverting pulleys. By adapting the length of the lever arm in accordance with these forces caused by the rope tensions. It is possible to reduce or even eliminate the tilting moment generated by the rope forces and tending to tilt the car.

The edges of the car ceiling are chamfered in such a way that the ceiling is lower near the side walls of the car. In this way a relatively efficient use of shaft space is obtained, since it is possible to place machines, overspeed governors and/or other shaft equipment on each side of the upper part of the car, even if there is not enough space between the car wall and the shaft wall for these devices or equipment, or at least to ensure that they have a sufficient distance from the car as required by safety regulations, even in the case where the car is located at the highest possible position.

Fig. 2 presents a diagrammatic view of the roping in an elevator according to the invention. The elevator is preferably an elevator without machine room, in which the drive machine 40 is placed in the elevator shaft. The elevator presented in the figures is a traction sheave elevator with machine on it and without counterweight, in which the car 1 moves along guide rails 2.

Fig. 2 presents how the ropes go around diverting pulleys and hoisting machine sheaves in an elevator made according to the invention, and fig. 3, 4 and 5 present a car supporting frame 30, the latter of which in fig. 4 is drawn to a length that allows the car to be installed inside the frame and in fig. 5 in a retracted or falling state that is easy to transport the frame, as long as the frame is transported as a complete unit together with the diverting pulleys mounted on it, allowing the ropes to be easily passed to these pulleys when the car supporting frame is on the bottom of the elevator shaft as shown in fig. 3. The car supporting frame is provided with guide rails 32 by means of which the car is positioned and controlled when moving in the vertical direction along the elevator guide rails 33. The upper part 34 and the lower part 35 of the car supporting frame are telescopically connected together by means of beam sections 36 and 37 of the side beams of the car frame, which sections are insertable into each other. The joining together of the upper and lower parts in a telescopic manner or another variable length manner can also be realized in some other way. The car supporting frame is provided with diverting pulleys for suspending the car on the ropes, comprising a first set of diverting pulleys 38, from which the ropes of a set of hoisting ropes go upwards, and a second set of diverting pulleys 39, from which the ropes of a set of hoisting ropes go downwards. Fig. 3 shows the diverting pulleys 42 to be installed in the upper part of the shaft but temporarily mounted on the car supporting frame, the hoisting machine 40 with a traction sheave (not shown) and preferably an auxiliary diverting pulley 41, which allows the roping on the machine to be implemented as so-called double wrap roping or the contact angle between the traction sheave and the ropes to be changed in some other way. In fig. 2, a set of hoisting ropes 44 is depicted as individual ropes with arrows indicating the rope travel, starting from a rope end fixing point 45 in the lower part of the shaft and ending finally in a rope force differentiating arrangement 46, which comprises a pulley system for maintaining a relative difference in rope tension between the two rope portions above and below the car. The rope force differentiating arrangement may also be implemented in other ways, which may involve a different solution with regard to the fixation of the rope ends. From the fixing point 45 the ropes go first to the rope sheave comprised in the differentiating arrangement 46 and then continue first to the diverting pulley 43 in the lower part of the shaft, from where the ropes go further to the down-ward diverting pulley 39 on the car and further one by one around the diverting pulleys in the lower part of the shaft and the down-ward diverting pulleys of the car until the ropes go from the last diverting pulley in the lower part of the shaft up to the machine 40. From the machine 40 the ropes go further to the first up-diverting pulley 38 on the car, passing round the diverting pulleys 42 in the upper part of the shaft and each up-diverting pulley 38 on the car in turn, until the ropes end from the last diverting pulley in the upper part of the shaft at the differentiating arrangement 46.

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 claims presented below. E.g. the number of times the hoisting ropes are passed between the diverting pulleys in the upper part of the elevator shaft and those on the car and between the diverting pulleys in the lower part of the elevator shaft and those on the car, is not a very decisive question as regards the basic advantages of the invention, although it is possible to obtain some additional advantages by using a plurality and even number of rope portions. It is obvious to the person skilled in the art that an embodiment according to the invention can also be implemented using odd suspension ratios above and below the car, in which case the compensating device is mounted in connection with the car or its components. In accordance with the examples described above, the person skilled in the art can vary the embodiment of the invention, instead of the coated metal pulleys, the traction sheave and rope pulleys can also be uncoated metal pulleys or uncoated pulleys made of some other material suited to the purpose.

It is also obvious to the person skilled in the art that the car and the machine assembly can be arranged in the cross-sectional area of the elevator shaft in an arrangement different from that described in the examples. The skilled person also understands that "car" may refer to a self-supporting car structure, an assembly consisting of a car and a car supporting frame, or also a car structure mounted inside a car supporting frame.

It is obvious to the skilled person that an elevator applying the invention can be equipped differently from the examples described above. It is further obvious to the skilled person that the elevator of the invention can be implemented using as hoisting ropes almost any flexible hoisting means, e.g. flexible ropes having one or more strands, flat belts, cogged belts, V-belts or some other type of belt suited to the purpose.

It is further obvious to the skilled person that the elevator of the invention may also be provided with a counterweight, in which case the counterweight of the elevator preferably has a weight below the weight of the car and is suspended by a separate set of ropes. The skilled person will understand that the elevator shaft is not strictly required for the elevator provided that sufficient safety protection is achieved for the various technical components.

Claims (7)

1. Elevator having a car with a car frame on which are mounted a first set of diverting pulleys from which the hoisting ropes go downwards and a second set of diverting pulleys from which the hoisting ropes go upwards, in which elevator the rope tension in the rope portion going from the first set of diverting pulleys is smaller than the rope tension in the rope portion going from the second set of diverting pulleys in a prescribed proportion,

the diverting pulleys of the first set are at a larger average distance from the car frame than the diverting pulleys of the second set.

2. An elevator according to claim 1, characterized in that at least one of the diverting pulleys of the first set is at a greater distance from the car frame than any of the diverting pulleys of the second set.

3. An elevator according to claim 1 or 2, characterized in that the diverting pulleys are disposed symmetrically on the same car sides as the guide rails.

4. Arrangement in an elevator with a car frame, which frame is provided with a first set of diverting pulleys from which the elevator hoisting ropes go downwards, and a second set of diverting pulleys from which the elevator hoisting ropes go upwards, said second set comprising at least one second diverting pulley, in which elevator the rope tension in the rope portion going from the diverting pulleys of the first set is smaller than the rope tension in the rope portion going from the diverting pulleys of the second set by a prescribed ratio, characterized in that the distance of the second diverting pulley from the plane of the car frame is substantially smaller than the distance of the first diverting pulley from the plane of the car frame by the same prescribed ratio as the rope tension in the rope portion going from the diverting pulleys of the first set is smaller than the rope tension in the rope portion going from the diverting pulleys of the second set.

5. A device according to claim 4, characterized in that the device comprises at least one holder for supporting at least one diverting pulley.

6. A device according to claim 4 or 5, characterised in that the tension of the up-going rope is at least twice as great as the tension of the down-going rope.

7. A device according to claim 4 or 5, characterised in that the tilting moment acting on the frame structure is zero.