ELEVATOR SYSTEM COMPRISING A PLURALITY OF DIFFERING SUPPORT MEANS

Abstract

An elevator system includes at least one car and at least one counterweight. At least two support means having different physical properties are arranged between the at least one car and the at least one counterweight.

Claims

1-8. (canceled)

9. An elevator system comprising: a car; two counterweights; two support means having different physical properties, a first of the support means being connected between the car and one of the counterweights and a second of the support means being connected between the car and another of the counterweights; and wherein the first and second support means are redundant with regard to a maximum load-carrying capacity to be carried in the elevator system.

10. The elevator system according to claim 9 wherein the first support means has a larger safety reserve than the second support means.

11. The elevator system according to claim 9 wherein the first support means is part of a first support means arrangement and the second support means is part of a second support means arrangement, the first support means arrangement having a larger number of the first support means than a number of the second support means in the second support means arrangement.

12. The elevator system according to claim 9 wherein the first support means has larger dimensions than dimensions of the second support means.

13. The elevator system according to claim 12 wherein the first support means has a larger cross-sectional area than a cross-sectional area of the second support means.

14. The elevator system according to claim 9 wherein the first support means has different vibration properties than vibration properties of the second support means.

15. The elevator system according to claim 9 wherein the first support means includes different materials or combinations of materials than materials included in the second support means.

16. The elevator system according to claim 9 wherein the first support means has a cross-sectional area shaped differently than a cross-sectional area of the second support means.

17. The elevator system according to claim 9 wherein the first and second support means have a same expansion properties.

Description

DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a representation of an elevator system according to an embodiment of the invention.

[0029] The drawing is merely schematic and is not to scale.

DETAILED DESCRIPTION

[0030] FIG. 1 is a highly schematized representation of an elevator system 100 according to an embodiment. The elevator system 100 has a car 102 and a counterweight 104 for the car 102. The car 102 and the counterweight 104 are connected to one another via a first support means 106 and at least a second support means 108. The support means 106, 108 have different physical properties.

[0031] In a conventional elevator system, a car can be suspended from a large number of standard steel cables. Together, the steel cables can have a safety factor of 12, for example. Traditionally, steel cables of identical strength and performance are used to distribute the load and braking forces evenly. Since all cables are the same, all cables can be equally tensioned and together reach a breaking point.

[0032] In the approach presented here, an asymmetry is inserted into the system in a targeted and conceptual manner. For example, the safety factor on one side can be set significantly higher than on the other side to ensure that after an expected service life, the weaker side always reaches the breaking point before the stronger side.

[0033] The weaker side can in this case be defined as a predetermined breaking point and monitored using simple methods. For example, a break in a cable on the weaker side can be detected by contact with a slack cable. When the cable break is detected, a brake of the car can be activated and the elevator system can be stopped and deactivated.

[0034] Since the second side is designed to be much stronger than the weak side, it can be ruled out that the break in the weak side will also result in a break in the strong side. The elevator system can therefore be safely evacuated and taken out of operation pending repairs.

[0035] If the strong side also breaks after the weak side breaks while the elevator system is at a standstill, it is at least ensured that the car is empty.

[0036] Alternatively or additionally, the cables can have different failure mechanisms that cannot occur simultaneously. One side can break, but the elevator system can be safely moved to a safe position using the second side.

[0037] Another reason for using embodiments of the approach presented here is that excitation frequencies typically arise when using steel cables as support means due to the cable lay length. If these meet systems of the elevator system that are capable of vibrating in resonance, elevator users will experience joint excitation and acoustic annoyance and/or vibration annoyance. This can be counteracted by support means, in particular cables, having different physical properties. For example, cables having different numbers of strands can be used to avoid a common excitation frequency. The cable expansion modules and diameters of both cable types can advantageously be selected to be identical.

[0038] The support means 106, 108 extend substantially in the vertical direction within an elevator shaft of the elevator system 100. The support means 106, 108 extend within the elevator shaft substantially in parallel with a rail system in order to guide the car 102 and the counterweight 104 in the vertical direction. At an upper end of the elevator shaft, the support means 106, 108 are deflected by 180° in order to connect the car 102 and the counterweight 104 to one another. Thus, the car 102 and the counterweight 104 are each moved in opposite directions by the support means 106, 108.

[0039] The support means 106, 108 are redundant in terms of their load-bearing capacity. Each support means 106, 108 alone is designed to carry a weight of the car 102 with passengers and a weight of the counterweight 104 with a safety reserve. Should the first support means 106 become damaged, the second support means 108 can safely carry and move the car 102 and the counterweight 104. The support means 106, 108 are in this case guided via separate guide rollers. However, the support means 106, 108 can also be guided via common guide rollers in order to ensure synchronous movement of the support means 106, 108.

[0040] In one embodiment, the first support means 106 has a larger safety reserve than the second support means 108. For example, the first support means 106 has a safety factor of eight, while the second support means 108 has a safety factor of four. The safety factor expresses by how many times the relevant support means 106, 108 is oversized relative to a permissible maximum load of the elevator system 100. Together, the support means 106, 108 have a safety factor of 12. Due to the different safety factors, it is extremely unlikely that the first support means 106 will fail. In contrast, the second support means 108 has a significantly higher probability of failure due to the significantly lower safety factor of four. Therefore, if one of the support means 106, 108 should fail, there is a very high probability that it will be the second support means 108. In the embodiment shown here, the second support means 108 in particular can be monitored.

[0041] In one embodiment, the elevator system 100 has a second counterweight 110. The second counterweight 110 is connected to the first support means 106 here.

[0042] In one embodiment, the first support means 106 is part of a first support means arrangement 112. The first support means arrangement 112 has six support means 106. The second support means 108 is part of a second support means arrangement 114. The second support means arrangement 114 has four support means 108. The support means 106 of the first support means arrangement 112 all extend via common guide rollers. Likewise, the support means 108 of the second support means arrangement 114 extend together via common guide rollers. The support means arrangements 112, 114 can have the same carrying capacity despite a different number of support means 106, 108.

[0043] In one embodiment, the first support means 106 has a larger cross-sectional area than the second support means 108. If the support means 106, 108 are cables, the support means 106, 108 have different cable diameters. If the support means 106, 108 are belts, the support means 106, 108 have different belt widths. Due to the different dimensions, the support means 106, 108 can have different safety factors and different vibration properties. For example, the first support means 106 having the larger cross-sectional area can have a lower natural frequency than the second support means 108 having the smaller cross-sectional area.

[0044] Furthermore, the support means 106, 108 can have different failure mechanisms due to the different cross-sectional areas. For example, due to the smaller cross-sectional area, the second support means 108 can be more flexible than the first support means 106 having the larger cross-sectional area. Due to the greater flexibility, the second support means 108 can be less susceptible to fatigue breaks.

[0045] In one embodiment, both support means 106, 108 are cables. The first support means 106 has a first inner structure. The second support means 108 has a second inner structure. The inner structure can influence the vibration properties of the support means 106, 108. For example, the first support means 106 has nine strands as the inner structure of the cable, while the second support means 108 has eight strands as the inner structure. Both support means in this case have the same cable diameter and expansion properties.

[0046] Alternatively or additionally, the first support means 106 can have a shorter lay length than the second support means 108. The lay length refers in this case to a cable length in which a strand is laid completely around the cable or around the cable circumference in a helix-like manner. The different lay lengths result in contact points with the guide rollers that are spaced differently from one another. The different distances between the contact points lead to different excitation frequencies of the support means 106, 108 at the same movement speed. The resulting vibrations are transmitted by the support means 106, 108 to the car 102, where they are weakened by destructive interference due to the different excitation frequencies and can even cancel each other out.

[0047] In one embodiment, the support means 106, 108 have different materials or combinations of materials. For example, a core element of the first support means 106 can consist of a synthetic fiber material and thus have a lower density than a core element of the second support means 108 made of a metal material.

[0048] The first support means 106 can also have strands made of a lighter material than the strands of the second support means 108. Due to the different density, the support means 106, 108 have different weights per meter and thus different vibration properties. The lighter first support means 106 can have a higher natural frequency than the heavier second support means 108.

[0049] In addition, the different materials can lead to different corrosion properties. Due to the different corrosion properties, one of the support means 106, 108 can be insensitive to a substance, while the other support means 106, 108 is attacked by the substance. The different corrosion properties can lead to different failure mechanisms.

[0050] Finally, it should be noted that terms such as “comprising,” “having,” etc. do not preclude other elements or steps, and terms such as “a” or “an” do not preclude a plurality. Furthermore, it should be noted that features or steps that have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above.

[0051] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.