SUSPENSION ARRANGEMENT FOR AN ELEVATOR

Abstract

An actively controllable suspension arrangement positions a car in an elevator system, the car being suspended by a suspension traction apparatus and displaceable within an elevator shaft by a drive. The suspension arrangement includes a carrier assembly having at least one fixator attaching the suspension traction apparatus to the carrier assembly, a displacement assembly for displacing the carrier assembly a load direction of the car, a position determination assembly indicating a real position of the car, and a controller controlling operation of the displacement assembly based on measurement signals from the position determination assembly. The suspension arrangement can be used for actively controlling and influencing a positioning and/or a motion of the car in order to perform e.g. a fast re-leveling of the car during stops and/or to compensate unintended speed variations of the car resulting e.g. from a yo-yo effect, seismic effect or similar effects.

Claims

1-15. (canceled)

16. A suspension arrangement for an elevator system, the elevator system including an elevator car suspended by a suspension traction means in a load direction and being displaceable within an elevator shaft upon controlled displacement of the suspension traction means, and a drive means for controlled displacing of the suspension traction means upon control by an elevator control of the elevator system, the suspension arrangement comprising: a carrier assembly including at least one fixator attaching the suspension traction means to the carrier assembly; a displacement assembly connected to the carrier assembly and operating to induce displacing of the carrier assembly parallel to the load direction; a position determination assembly for generating measurement signals indicating a real position of the elevator car within the elevator shaft; and a controller for controlling the operation of the displacement assembly, wherein the controller controls the operation of the displacement assembly in response to the measurement signals from the position determination assembly.

17. The suspension arrangement according to claim 16 wherein the controller receives control signals from the elevator control as well as the measurement signals from the position determination assembly, wherein the control signals from the elevator control represent control commands to the drive means for an intended displacement of the car, and wherein the controller controls the operation of the displacement assembly based on a comparison of the measurement signals from the position determination assembly with the control signals from the elevator control.

18. The suspension arrangement according to claim 16 wherein the controller controls the operation of the displacement assembly based on a detection of an overspeed or a periodically varying speed of the elevator car by analyzing the measurement signals from the position determination assembly.

19. The suspension arrangement according to claim 16 wherein the controller controls the operation of the displacement assembly based on a comparison of the measurement signals from the position determination assembly with predetermined reference signal patterns.

20. The suspension arrangement according to claim 16 wherein the controller controls the operation of the displacement assembly to re-level the elevator car when the elevator car is held by the drive means and the traction suspension means in a stop position.

21. The suspension arrangement according to claim 16 wherein the controller controls the operation of the displacement assembly to counteract a periodical speed variation of the elevator car.

22. The suspension arrangement according to claim 16 wherein the displacement assembly includes a hydraulics, and wherein a displaceable portion of the hydraulics is connected to the carrier assembly.

23. The suspension arrangement according to claim 16 wherein the displacement assembly is adapted to displace the carrier assembly parallel to the load direction by at least one of a distance of at least 3 cm and a velocity of at least 1 cm/s.

24. The suspension arrangement according to claim 16 wherein the suspension arrangement is adapted to displace the carrier assembly independent of any action of the drive means.

25. The suspension arrangement according to claim 16 wherein the suspension assembly is adapted to displace the carrier assembly into a biased position depending on a determined current load status of the elevator car.

26. The suspension arrangement according to claim 16 wherein the controller functions as a control loop regulating the operation of the displacement assembly at a frequency of at least 20 Hz.

27. The suspension arrangement according to claim 16 wherein the position determination assembly includes a sensor fixed at the elevator car and an indicator arrangement disposed along the elevator shaft, and wherein the sensor generates the measurement signals upon interaction with the indicator arrangement.

28. The suspension arrangement according to claim 27 wherein the indicator arrangement includes a continuous substrate having multiple marks at various positions along an extension direction of the indicator arrangement.

29. An elevator system including the suspension arrangement according to claim 16 comprising: an elevator car; a suspension traction means connected to the elevator car; a drive means displacing the suspension traction means for displacing the elevator car within an elevator shaft by controlled displacement of the suspension traction means; a support means fixedly arranged within the elevator shaft; and wherein the elevator car is connected to the support means by the suspension traction means and the suspension arrangement.

30. The elevator system according to claim 29 wherein a fixed portion of the suspension arrangement is connected to the support means and a displaceable portion of the suspension arrangement is connected to the suspension traction means.

Description

DESCRIPTION OF THE DRAWINGS

[0063] FIG. 1 shows an elevator system comprising a suspension arrangement according to an embodiment of the invention.

[0064] FIG. 2 shows an enlarged perspective view of a suspension arrangement according to an embodiment of the invention.

[0065] The figures are only schematic and not to scale. Same reference signs refer to same or similar features throughout the figures.

DETAILED DESCRIPTION

[0066] FIG. 1 shows an elevator system 1 according to an embodiment of the present invention. The elevator system 1 comprises an elevator car 3, suspension traction means 5, drive means 7 and a suspension arrangement 9.

[0067] The elevator car 3 is suspended by the suspension traction means 5. The suspension traction means 5 may comprise a plurality of belts or ropes which may carry the weight of the elevator car 3 and its payload in a load direction 51. In the example shown, the suspension traction means 5 engages support pulleys 11 fixed to a lower side of the elevator car 3 in a rotatable manner. Furthermore, the suspension traction means 5 also supports a counterweight 13.

[0068] The drive means 7 comprises an electric motor 15 driving a traction sheave 17 into rotating motion in order to thereby displace the suspension traction means 5 back and forth along a displacement direction 19 being substantially parallel to the load direction 51. Thereby, the elevator car 3 and the counterweight 13 may be displaced within an elevator shaft 4 in opposing vertical directions.

[0069] In the example shown in FIG. 1, one end 21 of the suspension traction means 5 is fixedly attached to a ceiling 25 of the elevator shaft 4 via a fixator 23. The fixator 23 may provide for a rigid fixed mechanical connection or a slightly elastic mechanical connection between the suspension traction means 5 and the ceiling 25 or any other fixed support means within the elevator shaft 4. However, such mechanical connection is passive in the sense that a positioning of the suspension traction means 5 with respect to the ceiling 25 of the elevator shaft 4 may not be actively influenced or varied.

[0070] In case, an opposite end 22 of the suspension traction means 5 would also be attached to the ceiling 25 with a similar mechanical connection, i.e. in a same passive manner, a positioning of the elevator car 3 within the elevator shaft 4 could only be influenced via specifically controlling the drive means 7.

[0071] However, in such conventional configuration, it has been observed that e.g. temporary length variations in the suspension traction means 5 occurring for example as a result of varying loads onto the elevator car 3 or as a result of external forces from the drive means 7, from bouncing passengers within the elevator car 3 or from e.g. seismic actions may lead to undesired motions of the elevator car 3.

[0072] For example, passengers quickly entering or leaving the elevator car 3 being stopped at one of the floors 27 may result in sudden changes in payload in the elevator car 3. Such weight variations may then induce an increase or decrease in length of the suspension traction means 5 which may result in a bottom 29 of the elevator car 3 being no longer flush with a bottom 31 of the floor 27 but instead forming an undesired step. Similarly, provoked force variations onto the elevator car 3 may result in a yo-yo effect during travelling of the elevator car 3.

[0073] Conventionally, attempts have been made to minimize such undesired effects. For example, a greater number of belts or ropes has been included into the suspension traction means 5 than would be necessary to carry the load of the elevator car 3 and the counterweight 13 in order to make the entire suspension stiffer. However, such additional components may add for example significant additional costs and/or weight to the elevator system 1.

[0074] Accordingly, in order to for example avoid such additional costs and/or provide for an increased security and/or increased ride quality at the elevator system 1, it is proposed to replace at least one of the passive mechanical connections of the suspension traction means 5 to a fixed structure within the elevator shaft 4 by an active suspension arrangement 9.

[0075] As very schematically shown in FIG. 1 and shown in FIG. 2 in an enlarged view of an exemplary embodiment, such suspension arrangement 9 comprises a carrier assembly 33, a displacement assembly 35, a position determination assembly 37 and a controller 39.

[0076] The carrier assembly 33 comprises fixators 41 to which the suspension traction means 5 may be attached. In the specific example shown in FIG. 2, eight fixators 41 are provided such that eight ropes (not shown in FIG. 2) may be attached to the carrier assembly 33. Therein, each fixator 41 comprises a first portion 43 fixedly connected with a respective one of the ropes or belts whereas a second portion 45 of the fixator 41 is mechanically held at a carrier plate 47 of the carrier assembly 33 via elastic means such as springs 49. Accordingly, any load held by the suspension traction means 5 in a load direction 51 may be elastically transmitted to the carrier plate 47 of the carrier assembly 33.

[0077] The displacement assembly 35 is provided with a hydraulics 53. In the example shown in FIG. 2, a lower part 52 of the hydraulics 53 is fixedly attached to a support means 55 such as a support beam 57 fixedly arranged within the elevator shaft 4. An upper part 54 of the hydraulics 53 may be displaced in a vertical direction with respect to the lower part 52 of the hydraulics 53 and is mechanically connected to the carrier assembly 33 such as to induce displacing of the carrier assembly's 33 carrier plate 47 together with its fixators 41 in directions parallel to the load direction 51.

[0078] The suspension arrangement 9 further comprises a sensor 59 and an indicator arrangement 61 forming part of the position determination assembly 37. The sensor 59 is attached to the elevator car 3 such as to be moved together with the elevator car 3 throughout the elevator shaft 4. The indicator arrangement 61 may be provided as elongate tape or ribbon attached to a sidewall of the elevator shaft 4 in an extension direction along the length of the elevator shaft 4.

[0079] Accordingly, using the sensor 59 and the indicator arrangement 61, the position determination assembly 37 may measure a real position of the elevator car 3 within the elevator shaft 4 and may provide corresponding measurement signals. Such measurement signals may be provided to the suspension arrangement's controller 39 e.g. via a signal line 63. This controller 39 may furthermore be connected to the drive means 7 or an elevator control 65 controlling this drive means 7 e.g. via a signal line 67. Furthermore, the controller 39 may be connected to the displacement assembly 35 in order to control its displacing action onto the carrier assembly 33. For example, the controller 39 may be connected via signal lines 69 to the hydraulics 53 such as to control a hydraulic fluid supply through hydraulic lines 71 to the hydraulics 53.

[0080] The controller 39 is adapted for controlling the displacement assembly 35 of the suspension arrangement 9 based on the measurement signals provided by the position determination assembly 37. Particularly, the controller 39 is adapted to receive such measurement signals together with the control signals from the elevator control 65 indicating an intended displacement of the car 3.

[0081] For example, based on a comparison of the control signals from the elevator control 65 with actual measurement signals from the position determination assembly 37, the controller 39 may determine whether an actual positioning of the elevator car 3 or an actual motion of the elevator car 3 is intended and is the result of an action of the drive means 7 controlled by the elevator control 65 or whether such positioning or motion is unintentional or exceeds an intentional motion. In the latter case, the controller 39 may activate the displacement assembly 35 of the suspension arrangement 9 such as to provoke displacing of the carrier assembly 33 together with the suspension traction means 5 fixed thereto in or against the load direction 51.

[0082] Accordingly, using the actively controllable suspension arrangement 9, actual information about the real position of the elevator car 3 within the elevator shaft 4 may be used for specifically counteracting against any unintended displacement or motion of the elevator car 3. Specifically, a displacement action of the displacement assembly 35 may be regulated depending, inter alia, on input signals comprising the measurement signals from the position determination assembly 37.

[0083] Embodiments of the suspension arrangement 9 and the elevator system 1 provided therewith may provide for a multiplicity of possible advantages. Particularly, various elevator functions may be improved using only one component, i.e. using the suspension arrangement 9.

[0084] For example, an excessively rigid suspension traction means 5 including more belts or ropes than actually needed for carrying the load of the car 3 and the counterweight 13 may be avoided as the actively controllable suspension arrangement 9 allows for actively compensating any lacking rigidity of the suspension traction means 5. Accordingly, costs for additional ropes or belts within the suspension traction means may be saved.

[0085] Furthermore, the suspension arrangement 9 may replace a car damping device otherwise provided for damping for example jerks onto the car 3.

[0086] Additionally, the suspension arrangement's ability for controllably generating a limited displacement of the elevator car 3 within the elevator shaft 4 may be advantageously used in case of an emergency braking action of the elevator car 3 in order to reduce or damp a maximum deceleration of the car 3.

[0087] Furthermore, torque ripples otherwise preferably occurring at low speeds and 1:1-suspension may be significantly damped using the suspension arrangement 9 (RQ-increase).

[0088] In areas of seismic activity, the suspension arrangement 9 may be used for damping or counteracting any undesired motions of the elevator car 3 due to seismic jerks.

[0089] Particularly in case the displacement assembly 35 is implemented with a hydraulic arrangement, additional elevator functions may be integrated into the suspension arrangement 9. For example, load measurement capabilities may be included by measuring a hydraulic pressure of a hydraulic fluid. Thus, other sensors conventionally provided for such purpose may be omitted. Furthermore, in a hydraulic system, unequal belt tensioning in the suspension traction means 5 may be avoided by implementing for example a fluid communication between various cylinders of a hydraulic system of the displacement assembly 35, each of a multiplicity of ropes or belts being mechanically connected to one of the hydraulic cylinders. Furthermore, no slack rope detectors may be necessary any more as one or more slacking ropes within a suspension traction means 5 generally result in a characteristic pressure variation which may unambiguously detected by the controller 39.

[0090] Finally, it should be noted that the term comprising does not exclude other elements or steps and the a or an does not exclude a plurality. Also elements described in association with different embodiments may be combined.

[0091] 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.