HK1211008B - Lift system with monitoring device and method for monitoring a lift system - Google Patents

Description

Elevator system with monitoring device and method for monitoring an elevator system

Technical Field

The invention relates to an elevator installation having a monitoring device for a support means, and to a method for determining the state of a support means in an elevator installation.

Background

In elevator installations, in order to support and/or drive the elevator car, steel ropes are conventionally used as support means. According to a further development of such a cable, a belt-like support means is also used, which has tension carriers and a jacket arranged around the tension carriers. Such belt-like support means cannot be monitored in a conventional manner, since the tensile carriers which determine the breaking load of the support means cannot be seen through the jacket.

In order to monitor the tensile carriers in such a belt-like support means, the tensile carriers can be subjected to an inspection current. In one or more of the circuits thus formed, the current, amperage, voltage, resistance or conductivity is measured. By means of the values determined in this way, the integrity or degree of wear of the support means can be deduced back. When the diameter of the tension carriers is reduced due to breakage of the respective wires or due to metal abrasion, the resistance of the tension carriers increases.

For example, publication DE3934654a1 discloses a series connection of all individual tensile carriers to a current meter, wherein it is checked that: whether an electric current flows through the series-connected tension carriers. This makes it possible to confirm that: whether one of the tension carriers is interrupted at a certain location.

Patent document US7123030B2 discloses a solution for calculating the resistance by measuring the current voltage by means of a kelvin bridge and a solution for comparing the known voltage value with the reference value.

Publication WO2005/094250a2 discloses a temperature-dependent determination of the electrical resistance or conductivity, in which the different ambient temperatures and thus the assumed, in particular in very high elevator shafts, possibly very different support means temperatures are taken into account.

WO2003/059798a2 discloses a belt-like support means for an elevator installation. Here, the load of the load receiving mechanism and thus the load of the car can be pushed back by determining the resistance of the tensile carrier of the load receiving mechanism. Furthermore, when an infinitely high electrical resistance is found, the fracture of the tensile carrier can also be confirmed by resistance measurement. For determining the resistance, for example, a wheatstone bridge can be used.

In all these known monitoring solutions for the support means, however, the disadvantages are: the environmental influences which influence the electrical resistance of the tensile carriers are only inadequately taken into account. Thus, in addition to the temperature, other factors also have an influence on the electrical conductivity of the tensile carriers, for example the magnetic field or the ambient humidity. Therefore, known monitoring solutions do not give a reliable representation of the state of the support means.

Disclosure of Invention

The object of the invention is to provide a method for determining the state of a support means, which takes into account different environmental influences on the electrical conductivity of tensile carriers and which can be used inexpensively and reliably. The invention also provides an elevator installation with a monitoring device for monitoring a support means, wherein different environmental influences on the electrical conductivity of tensile carriers of the support means are taken into account when determining the state of the support means.

In order to achieve the object, an elevator installation is initially proposed having a car and at least one support means, wherein the car is at least partially supported by the support means, and the support means comprises a plurality of electrically conductive tension carriers arranged parallel to one another, which are substantially enveloped by a casing. The elevator installation also comprises a monitoring device which switches the tension carriers or tension carrier groups into the measuring bridge as resistances in different or varying or changing configurations (i.e., in different configurations), so that the resistances of the different tension carriers or tension carrier groups can be compared with one another by means of the bridge voltage.

Such an elevator installation presents disadvantages in the first place, since the determination of the state of the support means cannot provide absolute values. But this device achieves that: the state of the tensile carriers of the support means is qualitatively determined without being distorted by environmental influences such as temperature, air humidity or magnetic fields. This is achieved by comparing tensile carriers which are subjected to substantially the same environmental influences. The state of the support means can thus be better evaluated by means of the device proposed here.

The solution of tensile carriers as a resistor in the bridge also has the following advantages: the corresponding monitoring device can be produced cost-effectively and can also be used in a stable and reliable manner. Furthermore, a parameter which can be determined easily and can also be determined easily is provided by means of the bridge voltage as an indicator for the state of the support structure. This simplifies the monitoring of the support means considerably and makes it possible to exclude distorted measured values and expression errors as far as possible.

The solution of the tensile carriers or groups of tensile carriers being connected as resistors in the measuring bridge in different configurations has the following advantages: each tension carrier or each tension carrier group can be compared with other tension carriers or tension carrier groups. This increases the confidence in the state of the individual tensile carriers or tensile carrier groups, since similar defects in different tensile carriers or tensile carrier groups can also be reliably detected.

In an exemplary embodiment, in each case one tensile carrier is connected as an electrical resistance in a measuring bridge. In this case, a plurality of tension carriers of a single support means can be connected to one another in a measuring bridge, or the tension carriers of different support means of an elevator installation can be connected to one another in a measuring bridge. This tension carrier connection has the following advantages: so that each individual tensile carrier of the support means can be checked with regard to its state. However, this connection arrangement requires a series of measurements in order to check all tension carriers of all support means of the elevator installation.

In an exemplary embodiment, a plurality of tensile carriers of the support means are each connected as a group in the form of an electrical resistance in the measuring bridge. In this case, groups of tension carriers of individual support means can be connected to one another in a measuring bridge, or groups of tension carriers of different support means of the elevator installation can be connected to one another in a measuring bridge. This connection scheme of the tensile carriers has the following advantages: so that fewer measuring processes are required to check all tension carriers of all support means of the elevator installation. By suitably bundling the tensile carriers into groups, an efficient monitoring of the support means can be achieved.

In an exemplary embodiment, all tensile carriers of a support means are each connected as a group in the form of an electrical resistance in a measuring bridge. This connection of the tensile carriers has the advantage that the individual tensile carriers of a support means do not necessarily have to be contacted individually, but rather can be contacted as an integral group. This simplifies the electrical contacting of the tensile carriers considerably. However, in an electrical contact or connection scheme for the tensile carriers in this way, no conclusions can be drawn about the individual tensile carriers of the support means.

In an exemplary embodiment, the tensile carriers of a group are each connected in series and in this way form an electrical resistance in the measuring bridge. In an alternative embodiment, the tensile carriers of a group are each connected in parallel to one another and in this way form an electrical resistance in the measuring bridge. Depending on the design of the support means, i.e. for example depending on the material and the diameter of the tensile carriers of the support means, one or the other of these two connection schemes can be advantageous. It should be noted here that: damage on the tensile carriers which causes a change in the electrical resistance of the tensile carriers is reliably identified. Depending on the type of measuring bridge and depending on the design of the tensile carriers, a connection scheme can be optimally adapted to the situation.

In the exemplary embodiment, four resistors, which are formed by one or more tensile carriers, are connected in a wheatstone bridge. Such a wheatstone bridge has the following advantages: by determining the bridge voltage, the deviating resistance can be reliably found. This ensures reliable identification of defective tensile carriers or defective groups of tensile carriers.

In an advantageous embodiment, the absolute resistance value of the tensile carriers or groups of tensile carriers cannot be determined by the monitoring device. This embodiment of the monitoring device has the advantage that the monitoring device can be produced inexpensively and simply.

In order to achieve the object mentioned at the outset, a method for determining the state of at least one support means in an elevator installation is also proposed. The elevator installation comprises a car and at least one support means, wherein the car is at least partially supported by the support means and the support means comprises a plurality of electrically conductive tensile carriers arranged parallel to one another, which are substantially encased by a casing. The method comprises the following steps: connecting tensile carriers or tensile carrier groups into a measuring bridge as resistors in different configuration modes; and the state of the support means is determined by comparing the electrical resistance of the tensile carriers or groups of tensile carriers by means of the bridge voltage.

This method is disadvantageous in the first place because it does not provide absolute values for evaluating the measurement results. But this method achieves: the state of the tensile carriers of the support means is qualitatively determined without being distorted by environmental influences such as temperature, air humidity or magnetic fields. This is achieved by comparing tensile carriers which are subjected to substantially the same environmental influences. This enables the state of the support mechanism to be evaluated more favorably.

The solution of accessing the tensile carriers or groups of tensile carriers in different configurations has the following advantages: the state of the individual tension carriers or tension carrier groups can be better concluded by comparing the tension carriers or tension carrier groups with a greater number of tension carriers or tension carrier groups.

In an exemplary embodiment, the tensile carriers each form an electrical resistance in the measuring bridge. In an alternative embodiment, a plurality of or all tensile carriers of the support means form an electrical resistance in the measuring bridge.

In an exemplary embodiment, the electrical resistance of each tension carrier or each tension carrier group of the elevator installation is compared with the electrical resistance of at least three other tension carriers or at least three other groups of tension carriers. This has the following advantages: in this way, sufficiently good conclusions can be drawn about the state of the tensile carriers or tensile carrier groups, which can be connected in a simple and reliable wheatstone measuring bridge. In this case, the state of four tensile carriers or four tensile carrier groups can be concluded by determining a parameter (in particular the bridge voltage). A very efficient and reliable method for determining the state of a support means in an elevator installation is thus provided.

In an exemplary embodiment, the absolute resistance value of the tensile carriers or groups of tensile carriers cannot be determined when the state of the support means is known. This method has the advantage, in turn, that unnecessarily many parameters need not be measured and evaluated. This prevents measurement errors and the risk of misinterpretation of the measurement results.

The solution disclosed here for determining the state of a support means or the monitoring device disclosed here can be used in different types of elevator installations. Thus, for example, elevator installations with or without a shaft, with or without counterweight or elevator installations with different transmission ratios can be used. In this way, the belt-like support means of each support car in the elevator installation can be monitored by the method or the device disclosed here.

Drawings

The invention is explained in detail symbolically and exemplarily with the aid of the figures. Wherein:

fig. 1 shows an exemplary embodiment of an elevator installation;

FIG. 2 illustrates an exemplary embodiment of a load bearing mechanism; and

fig. 3a to 3c each show an exemplary embodiment of a measuring bridge.

Detailed Description

The elevator installation 40 illustrated schematically and exemplarily in fig. 1 comprises an elevator car 41, a counterweight 42, as well as the support means 1 and a drive pulley 43 with a corresponding drive motor 44. The drive pulley 43 drives the support means 1 and thus moves the elevator car 41 and the counterweight 42 in opposite directions. The drive motor 44 is controlled by an elevator controller 45. The car 41 is configured to receive and transport people or cargo between floors of a building. The car 41 and the counterweight 42 are guided along guides (not shown). In this example, the car 41 and the counterweight 42 are suspended on respective load rollers 46. The support means 1 is fixed to the first support means fixing device 47 and is then first guided around the support rollers 46 of the counterweight 42. The support means 1 is then placed on the drive wheel 43, guided around the support rollers 46 of the car 41 and finally connected to the fixing point by means of the second support means fixing device 47. This means that: the support means 1 is moved by means of the drives 43, 44 at a speed which corresponds to a higher winding ratio than the movement of the car 41 or counterweight 42. In this example, the winding ratio is 2: 1.

The free end 1.1 of the support means 1 is provided with a contact device 2 for temporarily or permanently electrically contacting the tensile carriers and thus for monitoring the support means 1. In the example shown, such a contact device 2 is arranged on both ends 1.1 of the support means 1. In an alternative embodiment, which is not shown, only one is arranged on one of the support means ends 1.1 by means of the device 2, and the tensile carriers are electrically connected to one another on the other support means end 1.1. The support means end 1.1 is no longer loaded by the tensile forces in the support means 1, since these tensile forces have already been introduced into the building by means of the support means fastening device 47. The contact device 2 is arranged in the non-rolled-over region of the support means 1 and outside the loaded region of the support means 1.

In this example, the contact device 2 is connected to the monitoring device 3 at one end of the support means 1.1. The monitoring device 3 connects the tensile carriers of the support means 1 as electrical resistances in a measuring bridge. The resistances of the different tensile carriers can thus be compared with one another by means of the bridge voltage detected by the monitoring device 3. The monitoring device 3 is also connected to the elevator control 45. In this way, signals or measured values can be transmitted from the monitoring device 3 to the elevator control 45 in order to take into account the state of the support means 1, for example, known from the monitoring device 3, in the control of the elevator 40.

The elevator installation 40 shown in fig. 1 is exemplary. Other winding ratios and configurations (e.g., elevator installations without counterweight) are possible. The contact device 2 for contacting the support means 1 is arranged in accordance with the arrangement of the support means fastening device 47.

Fig. 2 shows a section of an exemplary embodiment of a support means 1. The support means 1 comprises a plurality of electrically conductive tensile carriers 5 arranged parallel to one another, which are encased by a casing 6. For the electrical contact of the tension carriers 5, the jacket 6 may be cut through or removed, for example, or the tension carriers 5 may also be electrically contacted at the end by the contact device 2. In this example, the support means is configured with longitudinal ribs on the traction side. Such longitudinal ribs improve the traction properties of the support means 1 on the drive wheel 43 and also facilitate the lateral guidance of the support means 1 on the drive wheel 43. However, the support means 1 can also be designed differently, for example without longitudinal ribs, or with a different number or different design of the tension carriers 5. The essential aspect of the invention is that the tensile carriers 5 are electrically conductive.

In fig. 3a to 3c, an example of a measuring bridge 12 is schematically shown. In this case, the resistors 14 are connected to one another in each case to form a measuring bridge 12. In this case, the power supply 13 supplies the total voltage applied to the bridge 12, and the bridge voltage 15 can be used as a parameter for the identity or the dissimilarity of the resistors 14. By using the tensile carriers 5 of the support means 1 individually or in groups as the electrical resistances 14 in the measuring bridge 12, information about the state of the tensile carriers 5 and thus also of the support means 1 can be obtained by evaluating the bridge voltage 15.

Fig. 3a shows a wheatstone measuring bridge 12. The four resistors 14 are connected to one another in such a way that the bridge voltage 15 is zero when all four resistors 14 are equal. Fig. 3b shows a measuring bridge 12, in which two resistors 14 are each connected in parallel and form an assembly. Overall, four such components form a measuring bridge 12, in which the bridge voltage 15 can in turn be used as a measure for the identity of the resistors 14. Fig. 3c shows a measuring bridge 12, in which 8 resistors 14 are connected. The bridge voltage 15 can be determined at a plurality of positions. The bridge voltage 15 can in turn be used as a measure for the equality of the resistances 14.

The measuring bridge shown here is an example for a suitable measuring bridge for knowing the state of the support means. It goes without saying that other types of measuring bridges can be applied to achieve the same technical effect. For example, 3/4 measuring bridge or half measuring bridge can also be used. In this way, a suitable measuring bridge can be selected depending on the design of the elevator installation or the support means.

Claims (11)

1. An elevator installation having a car (41) and at least one support means (1), wherein the car (41) is at least partially supported by the support means (1), wherein the support means (1) comprises a plurality of electrically conductive tension carriers (5) arranged parallel to one another, which are substantially enveloped by a casing (6), and further comprising a monitoring device (3) which switches the tension carriers (5) or groups of tension carriers (5) into a measuring bridge (12) as resistances (14) in different configurations, so that the resistances of different tension carriers (5) or groups of tension carriers (5) can be compared with one another by means of a bridge voltage (15).

2. Elevator installation according to claim 1, wherein individual tension carriers (5) are connected in each case as an electrical resistance (14) in the measuring bridge (12).

3. Elevator installation according to claim 1, wherein a plurality of tensile carriers (5) of a support means (1) are connected in groups as resistors (14) in the measuring bridge (12).

4. Elevator installation according to claim 1, wherein all tension carriers (5) of a support means (1) are connected in groups as resistors (14) in the measuring bridge (12).

5. Elevator installation according to claim 3 or 4, wherein the tension carriers (5) are each wired in series with one another, thereby forming an electrical resistance (14) in the measuring bridge (12).

6. Elevator installation according to claim 3 or 4, wherein the tension carriers (5) are each wired in parallel with one another, thereby forming an electrical resistance (14) in the measuring bridge (12).

7. Elevator installation according to one of claims 1-4, wherein four electrical resistances (14) formed by one or more tensile carriers (5) are connected in a Wheatstone measuring bridge (12).

8. A method for determining the condition of at least one support means (1) of an elevator installation (40), which elevator installation (40) comprises a car (41) and at least one support means (1), wherein the car (41) is at least partially supported by the support means (1), wherein the support means (1) comprises a plurality of electrically conductive tension carriers (5) arranged parallel to one another, which tension carriers are substantially enveloped by a casing (6), comprising the steps of:

connecting the tensile carriers (5) or groups of tensile carriers (5) in different configurations as resistors (14) in a measuring bridge (12); and

the state of the support means is determined by comparing the electrical resistances of the tensile carriers (5) or groups of tensile carriers (5) by means of a bridge voltage (15).

9. A method according to claim 8, wherein each tension carrier (5) forms an electrical resistance (14) in the measuring bridge (12).

10. A method according to claim 8, wherein a plurality or all of the tensile carriers (5) of one carrier means (1) form an electrical resistance (14) in the measuring bridge (12).

11. Method according to any of claims 8-10, wherein the electrical resistance of each tension carrier (5) or each group of tension carriers (5) of the elevator installation (40) is compared with the electrical resistance of at least three other tension carriers (5) or at least three groups of other tension carriers (5).