WO2009116985A1

WO2009116985A1 - Autonomous sway damper for use in an elevator system

Info

Publication number: WO2009116985A1
Application number: PCT/US2008/057184
Authority: WO
Inventors: Leandre Adifon; Raymond J. Moncini; Thomas W. Saxe; Randall Keith Roberts; Richard L. Hollowell
Original assignee: Otis Elevator Company
Priority date: 2008-03-17
Filing date: 2008-03-17
Publication date: 2009-09-24

Abstract

An exemplary elevator system (20) includes an elevator car (22) and a plurality of vertically extending members (32, 34, 36) associated with the elevator car (22) for supporting the elevator car and facilitating movement of the elevator car within a hoistway. A sway damper (40) is situated below the elevator car (22). The sway damper is moveable into a desired sway damping position independent of the elevator car (22).

Description

AUTONOMOUS SWAY DAMPER FOR USE IN AN ELEVATOR SYSTEM

BACKGROUND

[0001] Many elevator systems include an elevator car and counterweight that are suspended within a hoistway by roping comprising one or more load bearing members. Typically, a plurality of ropes, cables or belts are used for supporting the weight of the elevator car and counterweight and for moving the elevator car to desired positions within the hoistway. The load bearing members are typically routed about several sheaves according to a desired roping arrangement. It is desirable to maintain the load bearing members in an expected orientation based upon the roping configuration. [0002] There are other vertically extending members within many elevator systems. Tie down compensation typically relies upon a chain or roping beneath an elevator car and counterweight. Elevator systems typically also include a traveling cable that provides power and signal communication between components associated with the elevator car and a fixed location relative to the hoistway. [0003] There are conditions where one or more of the vertically extending members such as the load bearing member, tie down compensation member or traveling cable may begin to sway within an elevator hoistway. This is most prominent in high rise buildings where an amount of building sway is typically larger compared to shorter buildings and when the frequency of the building sway is an integer multiple of the natural frequency of a vertically extending member within the hoistway.

[0004] Various proposals have been made for mitigating or minimizing sway of a vertically extending member within a hoistway. One example approach includes using a swing arm as a mechanical device for inhibiting sway of a load bearing member, for example. United States Patent No. 5,947,232 shows such a device. Another device of this type is shown in U.S. Patent No. 5,103,937.

[0005] Another approach has been to associate a follower car with an elevator car. The follower car is effectively suspended beneath the elevator car and is positioned at the midpoint between the elevator car and a bottom of a hoistway for sway mitigation purposes. One drawback associated with this approach is that it introduces additional components and weight associated with the elevator car. In addition, the follower car position is dependent on the position of the elevator car to which it is coupled. [0006] Another approach includes controlling the position of an elevator car and the speed with which the car moves within a hoistway for minimizing the sway. It is known how to identify particular elevator car positions within a hoistway corresponding to particular building sway frequencies that will more effectively excite the vertically extending members. One approach includes minimizing the amount of time an elevator car is allowed to remain at such a so-called critical position when conditions conducive to sway are present. Various elevator movement control strategies are described in WO 2007/013434 and WO 2005/047724.

[0007] While the previous approaches have proven useful, those skilled in the art are always striving to make improvements.

SUMMARY

[0008] An exemplary elevator system includes an elevator car and a plurality of vertically extending members associated with the elevator car for supporting the elevator car and facilitating movement of the elevator car within a hoistway. A sway damper is situated below the elevator car. The sway damper is moveable into a desired sway damping position independent of the elevator car.

[0009] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[00010] Figure 1 schematically illustrates selected portions of an example elevator system.

[00011] Figure 2 schematically illustrates an example sway damper. [oooi2] Figure 3 schematically illustrates another example sway damper.

DETAILED DESCRIPTION

[oooi3] Figure 1 schematically illustrates portions of an elevator system 20. An elevator car 22 moves along a vertical oath within a hoistwav 24. In this example. the elevator car has a width W extending between guide rails 26 that guide movement of the elevator car 22 within the hoistway 24.

[oooi4] An elevator controller 30 controls movement and position of the elevator car 22 to provide desired elevator system performance. In this example, a machine 32 (e.g., a motor and brake) is controlled by the controller 30. A roping arrangement 32 (e.g., round ropes or flat belts) support the elevator car 22 and a counterweight (not illustrated). The roping arrangement 34 facilitates movement and position control of the elevator car 22 based upon operation of the machine 32 responsive to commands from the controller 30. [oooi5] The roping arrangement 34 is one example type of vertically extending member within the hoistway 24 associated with the elevator car 22. A traveling cable 36 is another example vertically extending member, which is used for providing power and signal communication between the elevator car 22 and the controller 30 or other devices. Another example vertically extending member is a compensation member 38 (e.g., a rope or a chain) that is used in a known manner.

[00016] Under certain conditions, it is possible for one or more of the vertically extending members to begin to sway or move laterally within the hoistway 24. This may occur, for example, during a high wind condition that induces building sway. The example of Figure 1 includes a sway damper 40 situated vertically beneath the elevator car 22. In one arrangement, the sway damper 40 can extend across the hoistway 24 in an amount that corresponds to the width W of the elevator car 22. The amount that the sway damper extends across the hoistway is not necessarily exactly the same as the width of the elevator. In the illustrated examples, the sway damper 40 includes components that establish a dimension of the sway damper that extends across more than half of the width of the hoistway 24 or the distance between the guide rails 26.

[oooi7] The sway damper 40 is moveable into a desired sway damping position independent of the elevator car. In other words, the sway damper 40 is autonomous and can be selectively controlled to move into any sway damper position beneath the elevator car 22 to address a particular sway condition.

[00018] Figure 2 schematically illustrates one example sway damper 40. This example includes a generally rectangular support frame 42 comprising a plurality of rigid beams, for example. Damping members 44 are supported on the rectangular suDDort frame 42 in a position where thev will selectively contact a vertically extending member, such as the compensation member 38 or the roping arrangement 34 responsive to lateral movement of such a vertically extending member. The damping member or members 44 are positioned to remain clear of the vertically extending members under normal operating conditions. Upon sway of the vertically extending member or members, a damping member 44 contacts the swaying member to minimize further sway or lateral movement. In this example, the damping members 44 are capable of rotating to accommodate relative vertical movement between them and the vertically extending member they are intended to selectively engage. [oooi9] In one example, the damping member 44 comprises a rigid material.

In another example, the damper member 44 includes at least some resilient material to provide a cushioning effect while damping any lateral movement or sway of a vertically extending member within the hoistway 22.

[00020] In the example of Figure 2, the sway damper 40 has a rope climber configuration that allows the sway damper 40 to move autonomously and independent of the elevator car 22. Climbing ropes 46 and 48 are positioned within the hoistway 24 to establish a vertical path along which the sway damper 40 may travel. In the illustration, the length of the vertical path along which the sway damper 40 travels is L. In some examples, L will correspond to a substantial portion of the hoistway. In other examples, L is less than the vertical path traveled by the elevator car 22. The vertical path along which the elevator car 22 travels corresponds generally to an entire height or length of the hoistway 24. The length L of the sway damper path, on the other hand, is significantly less. In one example, the sway damper 40 travels along a vertical path that is approximately one-third the length of the path followed by the elevator car 22. In other words, the sway damper 40 only travels along approximately one-third of the hoistway 24. In another example, the sway damper travels along a path that has a length L that is approximately one-quarter of the length of the vertical path followed by the elevator car 22. In such examples, the sway damper 40 is used for damping lateral movement or sway of a vertically extending member that is present within the lower portion of the hoistway 24.

[00021] In many situations, it will be sufficient to provide a sway damper 40 in the lower portion of the hoistway to obtain adequate sway mitigation. For example, only the portion of the traveling cable 36 that is below the car 22 typically is of concern during sway conditions. As known, the lower part of a traveling cable hangs beneath the car forming a loop.

[00022] The example of Figure 2 includes motorized rollers or sheaves 50 that climb along the ropes 46 and 48 responsive to commands from a controller that determines when sway mitigation is required. A known sensor of a sway condition provides information to the controller responsible for moving the autonomous sway damper 40 into a position corresponding to a determination regarding a current sway- inducing condition. Given this description, those skilled in the art will be able to determine how best to position the sway damper 40 to meet the needs of their particular situation.

[00023] The illustrated climbing ropes 46 and 48 are secured at one end to an elevator pit 52. Upper ends of the climbing ropes 46 and 48 are essentially fixed by bracket members 54 that are secured against the walls of the hoistway 24 in this example. The height at which the brackets 54 are placed, in part, establishes the length L of the vertical path along which the sway damper 40 is permitted to travel.

[00024] Figure 3 illustrates another example sway damper 40. In this example, a support beam 60 supports a damper member 62 that is positioned to engage at least one vertically extending member if that vertically extending member moves laterally or sways within the hoistway 24. [00025] The example of Figure 3 differs from the example of Figure 2 in at least two respects. The example of Figure 3 includes a single support beam 60 while the example of Figure 2 includes a generally rectangular support frame 42. The example of Figure 3 includes a rail climber arrangement including rollers 64 and motors 66 that are controlled to selectively propel the sway damper 40 along one or more guide rails 26 to move the sway damper 40 into a desired position when needed. As seen in Figure 3, the sway damper engages guide rails 26 on opposite sides of the hoistway. Otherwise, the operation of the example of Figure 3 is like that of the examples of Figures 1 and 2.

[00026] In the examples of Figures 2 and 3, the arrangement for moving the sway damper 40 includes a stabilizing feature that ensures smooth and reliable travel of the sway damper 40.

[00027] One feature of the disclosed examples is that they need only be deployed when needed. Otherwise, the sway damper can be parked out of the way. Another feature is that independently controlling the sway damper allows for fine tuning its vertical position to maximize sway attenuation and damping effectiveness.

[00028] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.

Claims

CLAIMSWe claim:

1. An elevator system, comprising: an elevator car; a plurality of vertically extending members associated with the elevator car, at least some being for supporting the elevator car and facilitating movement of the elevator car within a hoistway; and a sway damper situated below the elevator car, the sway damper capable of engaging at least one of said vertically extending members during a sway condition, the sway damper being moveable into a desired sway damping position independent of the elevator car.

2. The elevator system of claim 1, wherein the elevator car is moveable a vertical path having a first length corresponding to a height of the hoistway and the sway damper is moveable along a second vertical path having a second length that is shorter than the first length.

3. The elevator system of claim 2, wherein the second length is approximately one-third of the first length.

4. The elevator system of claim 2, wherein the second length is approximately one-quarter of the first length.

5. The elevator system of claim 1, comprising a plurality of climbing ropes supported in the hoistway and wherein the sway damper moves along the climbing ropes.

6. The elevator system of claim 1, comprising a plurality of guide rails that guide movement of the elevator car and wherein the sway damper moves along at least one of the guide rails.

7. The elevator system of claim 1, wherein the sway damper comprises at least one beam; and a damping member supported on the beam in a position to contact at least one of the vertically extending members responsive to lateral movement of the at least one vertically extending member.

8. The elevator system of claim 7, wherein the sway damper further comprises at least one motor to move said sway damper within said hoistway.

9. The elevator system of claim 1, wherein the sway damper comprises a generally rectangular support frame; and a damping member supported on the support frame in a position to contact at least one of the vertically extending members responsive to lateral movement of the at least one vertically extending member.

10. The elevator system of claim 9, wherein said sway damper further comprises at least one motor to move said sway damper within said hoistway

11. The elevator system of claim 1, wherein said sway damper extends across the hoistway an amount corresponding to a width of said elevator car.