EP1911713B1 - System and method for recording the position of a lift cabin - Google Patents

Description

The present invention relates to a system and a method for detecting the position of an elevator car.

In order to move an elevator car in an elevator shaft between different positions, the cabin is suspended on a flexible support and / or drive means. Recently, in addition to conventional steel cables and straps established as a support and / or drive means, for example, couple the elevator car with a counterweight and / or transmitted a tensile force for lifting or lowering the cabin.

To control the elevator car knowledge of their position, ie their location in the elevator shaft is required. The speed or acceleration of the elevator car can also be determined from the position by differentiation according to time, which is also used in the control (for example of the starting or braking process or in monitoring a maximum speed / acceleration), but also, for example, to determine the actual gross vehicle weight as a quotient of force exerted on the car by a drive means and the resulting acceleration.

To determine the position of the elevator car, the beats EP 1 278 693 B1 a arranged on the elevator car encoder, which cooperates positively with a separate, strained in the shaft timing belt. The disadvantage of this proposal requires an additional timing belt.

The WO 2004/106209 A1 therefore proposes to encode the strap itself and detect its position by means of a detector arranged in the elevator shaft. According to the document, the coding should preferably be realized by a magnetic material embedded in the belt, changes (in particular enlargements) of wires arranged in the belt or an additional cable in the belt and be detected contactlessly by a corresponding detector. Of grooves in the belt advises the WO 2004/106209 A1 due to the noise problems explicitly.

When capturing the encoding, like the WO 2004/106209 A1 suggests that the belt moves not only according to the movement of the elevator car, but can also move relative to the detector due to longitudinal, transversal and / or torsional vibrations, for example, by system inertia, movements of the cabin occupants or stick-slip effects in the Guiding the elevator car to be induced. Such additional movements of the belt are erroneously detected by the detector as changes in position of the elevator car and falsify the position determination. These errors increase when the speeds or even accelerations are determined from the positions.

Another disadvantage of the from the WO 2004/106209 A1 known system is that the proposed detectors, in particular optical or magnetic systems, require electrical energy and so in case of damage, such as a fire are no longer functional, so that it is no longer possible, with their help, the elevator car safely in a predetermined position (For example, an emergency exit position to the nearest floor or the ground floor), for example, by the elevator is driven manually.

After all, those are in the WO 2004/106209 A1 proposed systems for the conditions prevailing in a hoistway environmental conditions, in particular a contamination or wear of the belt, not optimal, since on the one hand, the magnetic or optical encoding weakened and on the other hand, the sensitive detectors necessary for their detection can be damaged.

Starting from the WO 2004/106209 A1 It is therefore an object of the present invention to provide a system and a method for detecting the position of an elevator car, which is not or only slightly affected by vibrations of the belt.

This object is achieved by the method and apparatus defined in the independent claims.

A system for detecting the position of an elevator car according to the present invention comprises a belt on which the elevator car is suspended, and a detector for detecting the position of the belt. According to the invention, the belt has toothing on a first side, into which a toothed wheel of the detector engages positively.

As a result, longitudinal vibrations in the belt longitudinal direction, torsional vibrations about the belt longitudinal axis and transverse vibrations in the direction of the belt transverse axis do not affect the detected position of the belt or only slightly, because they are attenuated or even prevented by the positive engagement of the gear in the teeth of the belt, and on the other hand Relative movement of the belt in a direction other than the rolling direction of the toothing, as occurs in the aforementioned torsional or transverse oscillations, cause little or no change in the angular position of the gear.

In addition, the mechanical, positive tapping the belt position by means of the gear does not necessarily require electrical energy. Therefore, a system according to a preferred embodiment of the present invention allows determination of belt position even in the event of a power failure due to, for example, a fire, thereby allowing manual control of the elevator car to an emergency exit position.

The belt position mechanically gripping gear can be compared to the conditions prevailing in the elevator shaft environmental conditions, in particular dirt, moisture and the like much more resistant than known optical or magnetic detectors. It is also not disturbed by electrical or magnetic fields, as they may occur, for example, in the vicinity of an elevator car lifting the electric motor. Even changing lighting conditions, such as when connecting maintenance lamps in the elevator shaft, do not affect the position detection by means of a gear, in contrast to optical systems.

In the present case, toothing is understood to mean an arrangement of alternating projections (teeth) and depressions (tooth spaces) which extend at least partially in the direction of the transverse axis of the belt, in particular straight, oblique, double or multiple toothings, the individual projections and the ends preferably complementary thereto Recesses in the toothing or the gear, for example, may have a kreissegment-, cycloid or involute-shaped cross-section. Such gears, in particular helical gears or gears with involute or round teeth, can advantageously reduce the belt vibrations and noises occurring during operation. You can also enable a very precise position determination.

Preferably, a clamping element such as one or more guide rollers or a spring-loaded tensioner bias the belt against the gear and so ensure the positive engagement. As a result, vibrations of the belt that affect the position determination, further reduced or completely suppressed.

The belt may comprise a plurality of cables or strands of single or multiple twisted wires and / or plastic yarns which serve as tension members and are enveloped by a belt body, for example made of an elastic plastic. The toothing can be formed by prototyping this plastic sheath. In a preferred development, the plastic covering for this purpose may have one or more layers having the toothing of another material, in particular another plastic, which is preferably particularly hard, dimensionally stable and / or abrasion resistant.

In a preferred embodiment, the gear is coupled to a rotary encoder, in particular an incremental rotary encoder or angle encoder, which outputs a position signal corresponding to the absolute or relative angular position. A rotary encoder for outputting a position signal which corresponds to the relative angular position can be particularly simple, cost-effective and / or robust. By adding up the complete revolutions, the absolute position of the cabin can be determined indirectly even with such a rotary encoder.

Advantageously, a rotary encoder can be used, which specifies the absolute angular position, that is, the number of (part) revolutions of the gear from a zero position directly. For example, a tape wound on the shaft of the encoder can indicate the absolute position of the belt. Similarly, the gear may be coupled to the encoder via a translation, so that a complete revolution of the encoder corresponds to several revolutions of the gear. Particularly advantageous, the encoder use a Gray encoding. In a particularly preferred embodiment, the rotary encoder comprises a multi-turn rotary encoder, which contains two or more code discs, each having one or more parallel code tracks and are coupled together via a reduction gear to determine the absolute angular position.

The output of the absolute angular position has the advantage that no positions, in particular not the previously executed complete revolutions of the gear must be stored. Thus, for example, after a power failure by detecting the absolute angular position directly the position of the belt can be determined without first having to approach a reference position again.

Mixed forms are also possible in which, for example, the rotary encoder indicates the position of the belt, starting from one floor each, i.e. after moving the car one floor again displays the same position. In a processing logic, the absolute position of the belt or of the car can then be determined in turn by adding up the floors that have been traveled. In the event of damage, it may then be sufficient to determine the position of the car relative to the nearest shaft door in order to move the car safely into an emergency exit position.

An inventive system may further comprise a processing unit for determining the position of the elevator car from the position signal. As explained above, this can be obtained from the encoder, the absolute or relative angular position. As a relative angular position while the executed by the gear or encoder rotation modulo 2π is referred to, while the absolute angular position denotes the entire, relative to a reference position executed rotation, which can therefore also be a multiple of 2π.

When the system is put into operation, it is preferably calibrated, the processing unit storing, in particular, a reference position of the belt. Starting from this reference position, the processing unit then determines a theoretical position of the elevator car from the absolute angular position of the rotary encoder, for example by multiplying it by the pitch circle radius of the gear wheel. If the processing unit receives only a relative angular position, it adds up the executed complete revolutions and adds this to the relative angular position before multiplying this sum by the pitch circle radius of the gear.

The belt can, for example in the form of a pulley, over-or underpinned hinged to the elevator car, i. be attached or deflected so that a change in position of the belt does not correspond directly to a change in position of the elevator car. If, for example, the belt is articulated to the elevator car via a loose roller, then the processing unit halves the position signal or the position change of the belt, before calculating the position of the elevator car in the shaft.

In addition to these systematic differences between the position of the belt and the elevator car, further deviations may occur as the belt stretches longitudinally due to, for example, static or dynamic loads. Therefore, in a preferred embodiment, the processing unit comprises a correction unit for correcting the position signal. In this case, for example, correction values which take into account the actual weight of the elevator car, the stretching of the belt occurring here or the like, can be stored as table values. For example, if it is determined by an actual cabin weight detection device that it corresponds to the maximum permissible total weight and it is known from tests or calculations that the belt will expand by 10% relative to the nominal weight, the correction unit will correct that from the processing unit the angular position determined theoretical cabin position by 10%.

Likewise, a car position determined by another measuring device, such as a contact switch, which is triggered by the elevator car, can also be taken into account in the correction of the position determination. For example, the offset between the theoretical car position calculated from the position of the belt by the processing unit and the actual car position detected by such a measuring device, which may result from, for example, stretching of the belt, may be detected in the correction unit be stored. Subsequently, the car positions determined by the processing unit can be corrected by this stored offset, advantageously this offset value is updated as soon as a new cabin position has been detected by the further measuring device.

According to a preferred embodiment, the belt has a second side facing away from the first side, via which the belt is frictionally driven by a drive wheel or a drive shaft.

In a particularly preferred embodiment, the belt has on its second side at least one in the belt longitudinal direction oriented V-rib or a flat surface over which the belt is in contact with the drive wheel or with the drive shaft. As a result, advantageously the same driving capability can be realized at a lower belt tension. At such lower belt tensions occur stronger belt vibrations, which adversely affect the position determination in conventional detectors. However, the inventive combination of first belt side gearing with V-ribbed belts on the second side of the belt allows determination of the position of the belt which, as stated above, is less affected by such belt vibrations. Advantageously, such V-ribs guide the belt laterally on the driving or deflection wheels. This prevents sideways movement of the belt and allows easy position detection by the detector.

The toothing may be formed in a particularly preferred embodiment on a first side of a flat belt, which is opposite to a second side, which engages with at least one driving and / or deflecting wheel in contact or in contact. Thus, a relatively wide toothing can be realized, which is less sensitive with respect to the transversal teeth occurring to the gear of the detector. In addition, the drive and / or diverting wheels bias the belt against the gear teeth and thus increase the reliability and precision of the meshing.

Alternatively, the toothing can also be formed on a narrow side of a flat belt, which is preferably oriented approximately at right angles to a side which engages with one or more driving and / or deflection wheels. Since a flat belt in its transverse direction due to the higher area moment of inertia stiffer against bends is, such a toothing be dimensionally stable, so that deformations of the belt, which would affect the position determination, are lower.

Finally, the belt, which is preferably in the form of a flat belt, can engage with or engage in contact with at least one of the driving and / or deflection wheels with its first side having the toothing. The first side opposite the second side may be flat to reduce the friction on pulleys or for guiding in driving or deflecting wheels also have a profile, for example, also a toothing or one or more V-ribs. The belt can engage only with its first toothed side, or only with its opposite second side, which preferably has V-ribs, or with its first and second sides with one or more driving and / or deflection wheels.

In a particularly preferred embodiment, the belt always wraps around an arrangement of deflecting and / or driving wheels with the same second side opposite the first side, so that its first side, which carries the toothing, does not come into contact with these deflecting and / or driving wheels comes. This protects the teeth and thus increases the life of the system.

In particular, for this purpose, the belt between two wheels of the arrangement of deflecting and / or driving wheels can be twisted about its longitudinal axis. For example, if the belt wraps around two consecutive wheels in the same plane but in opposite directions, the belt between these two wheels may be twisted 180 ° about its longitudinal axis so that it wraps both wheels with the same (second) side. On the other hand, if the axes of the two consecutive wheels are not parallel, but oriented at right angles to one another, the belt may be twisted by the corresponding angle, in this case 90 °.

In particular deflection wheels, which do not introduce tensile forces into the belt, but only lead to it, can also come with the first, provided with the toothing side of the belt into engagement, since on the one hand, the teeth hardly stressed, but on the other hand, especially for example in a double helical gearing, the belt is also sufficiently guided in the transverse direction.

In one embodiment of the present invention, the detector is disposed inertially fixed in an elevator shaft in which the elevator car travels. This has the advantage that the position signals generated by the detector can be easily transmitted to an inertial fixed elevator control.

In case of failure of the electrical power supply, an inventively provided with a gear detector, which cooperates positively with the belt and mechanically picks off its position, preferably also without electrical energy to enable a position determination and thus a manually driven displacement of the car in an emergency exit position. For example, in the event of a power failure to evacuate passengers, a driving wheel on the driving machine can be turned by hand while a detector, which also visually displays the position, is observed. Preferably, such a detector indicates the absolute position of the belt. By observing this detector, it can be ascertained in the event of an evacuation, when the manually raised or lowered cabin has reached a predetermined emergency exit position (for example, on the ground floor).

Preferably, the gear between a drive wheel and the suspension of the elevator car is arranged inertial fixed, so that strains of the belt in the range of a counterweight does not affect the position determination.

In another embodiment of the present invention, the detector is disposed on the elevator car. Thus, the position signal can be made available directly in the elevator car. On the other hand, the belt is guided on the elevator car usually by one or more guide rollers, by which it can be advantageously biased against the gear.

Fig. 1

eine Aufzuganlage mit einem System zur Erfassung der Position einer Aufzugkabine nach einer ersten Ausführung der vorliegenden Erfindung in schematisierten Form; und

Fig. 2

eine Aufzuganlage mit einem System zur Erfassung der Position einer Aufzugkabine nach einer zweiten Ausführung der vorliegenden Erfindung in einer der Fig. 1 entsprechenden Darstellung.

Fig. 3

einen Abschnitt eines zur Erfassung der Position der Aufzugkabine verwendbaren Riemens

Other objects, advantages and features of the present invention will become apparent from the dependent claims and the embodiments described below. This shows:

Fig. 1

an elevator system with a system for detecting the position of an elevator car according to a first embodiment of the present invention in schematic form; and

Fig. 2

an elevator installation with a system for detecting the position of an elevator car according to a second embodiment of the present invention in one of Fig. 1 corresponding representation.

Fig. 3

a portion of a usable for detecting the position of the elevator car belt

Fig. 1 shows an elevator system with a vertically movable in a shaft 7 elevator car 1. To raise and lower the cabin, a belt 2 is fixed at one end in the elevator shaft (not shown) and runs from there via two arranged on the roof of the car 1 guide wheels 5 and one driven by an electric motor (not shown) driving wheel 4 to a deflection wheel on the counterweight. 6

The belt is designed as a flat belt, in which a plurality of wire ropes are arranged as a tensile carrier in a belt body made of polyurethane. He wraps around the drive wheel 4 and the guide wheels 5 with a second flat side 2.2 (in Fig. 1 shown dark). This has a plurality of extending in the belt longitudinal V-ribs which are in engagement with complementary grooves in the drive wheel 4 and the guide wheels 5. As a result, the belt tension can be significantly reduced and at the same time a sufficient driving ability of the drive wheel 4 can be ensured.

Since the belt, the drive wheel 4 and the adjacent guide wheel 5 wraps in opposite directions (in Fig. 1 is the belt 2, starting from the counterweight 6 to the drive wheel 4 mathematically negative, bent around the subsequent guide wheel 5 mathematically positive), the belt 2 between these two wheels 4, 5 is twisted by 180 ° about its longitudinal axis, so that in each case his second, provided with the V-rib flat side 2.2 with the guide surfaces of the wheels 4, 5 engages.

On the second flat side 2.2 opposite first flat side 2.1 (in Fig. 1 bright) of the belt 2 is a toothing formed in which a gear 3A of a detector (not shown) engages. The gear 3A is arranged in the vicinity of the drive wheel 4 inertially fixed in the elevator shaft 7, so that the belt 2 is guided by the drive wheel 4 and the gear 3A. If the gear wheel and the drive wheel are arranged close enough to each other, in particular separated only by a gap which substantially corresponds to the belt thickness, the drive wheel advantageously presses the belt onto the gear wheel and thus prevents teeth from skipping, which improves the precision of the position detection.

The gear 3A is connected to a rotary encoder (not shown) which controls the relative angular position of the gear, i. whose rotation modulo determines 2π and outputs a corresponding signal to a processing unit. This determines the absolute position of the belt 2 by adding the complete revolutions already made according to their sign (i.e., subtracting opposite revolutions) by multiplying the resulting total angle (relative angular position plus full revolutions) by the pitch circle radius of the gear 3A. The processing unit subsequently halves this value to take account of the pulley arrangement of the belt 2 and determines therefrom the position of the car 1 in the shaft 7.

Each time the car 1 operates a contact switch (not shown) located near a hoistway door, a correction unit detects this actual position of the car 1 and compares it with the theoretical value determined from the belt position. If the value determined from the belt position deviates from the thus determined actual position of the car 1 due to, for example, belt elongation or skidding in gearwheel 3A, the correction unit stores this deviation and subsequently adds it to the theoretical car position determined from the gear position.

Since the belt position is detected relatively precisely and with high resolution by the mechanical tapping, the speed or acceleration of the belt can also be precisely determined by simple or twofold differentiation with respect to time, whereby in particular a constant belt elongation can be disregarded. This allows monitoring of maximum occurring speed and acceleration values, the departure of predetermined speed profiles and an estimate of the total car mass from the quotient of the force exerted by the drive wheel 4 on the belt 2 traction and the resulting acceleration.

Fig. 2 shows an elevator system with a system for detecting the position of an elevator car according to a second embodiment of the present invention in one of Fig. 1 corresponding representation. The same elements are provided with matching reference numerals, so that reference is made to their explanation to the above description and will be discussed below only on the differences from the first embodiment.

In the second embodiment, a gear 3B is rotatably arranged on the car 1 and engages in the toothing on the first side 2.1 of the belt 2 in the vicinity of the one guide wheel 5, so that the belt between the guide wheel 5 and gear 3B is additionally guided.

The gear 3B is coupled via a reduction with a rotary encoder (not shown) such that a method of the elevator car 1 between a top and bottom maximum possible position at which the gear 3B performs several complete revolution, just one complete revolution corresponds to an encoder disc. Thus, the absolute angular position of the encoder disc directly reflects the absolute position of the belt 2 from which, as in the first embodiment, the position of the car 1 can be determined.

Fig. 3 shows a portion of the belt described above, serving as a support and drive means for the elevator car and for detecting the position of the belt 2. The belt has substantially the shape of a flat belt. On its first side 2.1 this has a toothing (10) with transverse to its longitudinal direction oriented teeth, in which - as in the Fig. 1 and 2 shown - a gear of the detector engages positively. On its second flat side 2.2, the belt has a plurality of extending in the belt longitudinal direction V-ribs 8, which come with approximately complementary grooves in the drive wheel 4 and the guide wheels 5 in engagement. Reference numeral 9 designates tensile carriers which are integrated into the belt body of the belt 2 and are preferably designed as wire ropes or synthetic fiber ropes. The tension members are required because the strength of the belt body is not sufficient to transmit the tensile forces occurring in the belt.

Claims (10)

1. Lift installation with a system for detecting the position of a lift cage (1), with a belt (2) at which the lift cage is suspended and a detector for detecting the position of the belt, characterised in that the belt has on a first side (2.1) a toothing (10) in which a gearwheel (3A; 3B) of the detector mechanically positively engages, wherein the belt (2) has a second side (3.2) which is remote from the first side (2.1) and by way of which the belt (2) is driven by a drive wheel (4) or a drive shaft by friction couple.
2. Lift installation according to claim 1, characterised in that the gearwheel is coupled with a rotation transmitter which issues a position signal corresponding with the absolute or relative angular position.
3. Lift installation according to claim 2, characterised in that it further comprises a processing unit for determining the position of the lift cage from the position signal.
4. Lift installation according to claim 3, characterised in that the processing unit comprises a correction unit for correction of the position signal.
5. Lift installation according to any one of the preceding claims, characterised in that the belt (2) has on the second side (2.2) remote from the first side one or more wedge ribs (8) or a planar surface, by way of which the belt (2) is disposed in contact with the drive wheel (4) or the drive shaft.
6. Lift installation according to any one of the preceding claims, characterised in that the belt loops around an arrangement of deflecting and/or drive wheels (4, 5) by the same side.
7. Lift installation according to claim 6, characterised in that the belt is twisted about its longitudinal axis, in particular through 180°, between two wheels of the arrangement of deflecting and/or drive wheels.
8. Lift installation according to any one of the preceding claims, characterised in that the detector is arranged to be inertially fixed in a lift shaft (7) in which the lift cage moves.
9. Lift installation according to any one of the preceding claims 1 to 7, characterised in that the detector is arranged at the lift cage.
10. Method for detecting the position of the lift cage (1) by means of a lift installation according to any one of the preceding claims, comprising the steps of detecting the angular position of the gearwheel (3A, 3B) and determining the position of the lift cage from this angular position.

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