Patent Publication Number: US-11649138-B2

Title: Elevator system monitoring and control based on hoistway wind speed

Description:
BACKGROUND 
     Elevator systems are useful for carrying passengers and items between different levels of a building. Many elevator systems are traction-based and include traction ropes that suspend the elevator car and a counterweight. A machine causes movement of a traction sheave that, in turn, causes movement of the traction ropes for moving the elevator car as desired. One feature of traction-based elevator systems is a compensation assembly including compensation ropes suspended beneath the car and counterweight and a tie down mechanism near the bottom of the hoistway. The compensation assembly facilitates maintaining appropriate tension on the traction ropes to achieve desired traction. 
     Certain conditions may develop that introduce or cause the ropes to sway or move laterally from side to side. Rope sway is problematic. At a minimum, rope sway introduces vibration and hinders ride quality. In some situations, the rope sway can be extensive enough to cause the swaying ropes to contact other system components or the hoistway walls, which can damage those components or the ropes. High rise buildings are particularly susceptible to rope sway because of the extensive length of the ropes. 
     A variety of rope sway mitigation proposals have been made but none of them adequately address hoistway wind as a potential cause of rope sway. 
     SUMMARY 
     An illustrative example embodiment of an elevator system monitoring assembly includes a wind detector configured to detect wind in a hoistway and to provide a wind detector output regarding the detected wind. A processor is configured to receive the wind detector output, determine whether at least one characteristic of the detected wind satisfies at least one predetermined criterion corresponding to an effect on the elevator system, and provide an indication of the satisfied criterion, the effect on the elevator system, or both. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of the previous paragraph, the wind detector comprises an anemometer and the wind detector output indicates a speed of detected wind. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the wind detector output indicates a frequency of gusts of the detected wind. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the at least one predetermined criterion comprises a plurality of predetermined criteria; the predetermined criteria comprise a first wind speed threshold, a second wind speed threshold and a third wind speed threshold; the second wind speed threshold is higher than the first wind speed threshold; the third wind speed threshold is higher than the second wind speed threshold; and the processor is configured to determine whether a magnitude of a speed of the detected wind exceeds any of the thresholds. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the processor indication comprises a first indication that the wind condition requires attention when the magnitude of the speed of the detected wind exceeds the first wind speed threshold, a second indication that the wind condition requires slowing down the elevator system when the magnitude of the speed of the detected wind exceeds the second wind speed threshold, and a third indication that the wind condition requires at least temporarily shutting down the elevator system when the magnitude of the speed of the detected wind exceeds the third wind speed threshold. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the predetermined criteria comprise at least one threshold frequency, the processor is configured to determine a frequency of gusts of the detected wind based on the wind detector output, and the indication is based on whether the determined frequency of gusts exceeds the threshold frequency. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the indication provides information regarding the effect on the elevator system based on the speed of the detected wind and the frequency of gusts of the detected wind. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the effect on the elevator system corresponds to a likelihood that rope sway in the elevator system will result from the detected wind. 
     In an embodiment having at least one feature of the elevator system monitoring assembly of any of the previous paragraphs, the at least one predetermined criterion comprises at least one threshold frequency, the processor is configured to determine a frequency of gusts of the detected wind based on the wind detector output, and the indication is based on whether the determined frequency of gusts exceeds the threshold frequency. 
     An illustrative example embodiment of an elevator system includes an elevator car, a counterweight, a plurality of traction ropes suspending the elevator car and the counterweight, a compensation assembly including a plurality of compensation ropes suspended beneath the elevator car and the counterweight, and the monitoring assembly of any of the previous paragraphs. 
     An illustrative example embodiment of a method includes detecting wind in a hoistway using a wind detector, determining whether at least one characteristic of the detected wind satisfies at least one predetermined criterion corresponding to an effect on an elevator system in the hoistway, and providing an indication of at least one of the satisfied criterion and the effect on the elevator system. 
     In an embodiment having at least one feature of the method of the previous paragraph, detecting the wind comprises detecting a speed of the detected wind. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, detecting the wind comprises detecting a frequency of gusts of the detected wind. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, the at least one predetermined criterion comprises a plurality of predetermined criteria; the predetermined criteria comprise a first wind speed threshold, a second wind speed threshold and a third wind speed threshold; the second wind speed threshold is higher than the first wind speed threshold; the third wind speed threshold is higher than the second wind speed threshold; and determining whether at least one characteristic of the detected wind satisfies at least one predetermined criterion comprises determining whether a magnitude of a speed of the detected wind exceeds any of the thresholds. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, providing the indication comprises providing a first indication that the wind condition requires attention when the magnitude of the speed of the detected wind exceeds the first wind speed threshold, providing a second indication that the wind condition requires slowing down the elevator system when the magnitude of the speed of the detected wind exceeds the second wind speed threshold, and providing a third indication that the wind condition requires at least temporarily shutting down the elevator system when the magnitude of the speed of the detected wind exceeds the third wind speed threshold. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, the predetermined criteria comprise at least one threshold frequency, determining whether at least one characteristic of the detected wind satisfies at least one predetermined criterion comprises determining a frequency of gusts of the detected wind and determining whether the determined frequency exceeds the threshold frequency, and the indication is based on whether the determined frequency of gusts exceeds the threshold frequency. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, the indication provides information regarding the effect on the elevator system based on the speed of the detected wind and the frequency of gusts of the detected wind. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, the effect on the elevator system corresponds to a likelihood that rope sway in the elevator system will result from the detected wind. 
     In an embodiment having at least one feature of the method of any of the previous paragraphs, the at least one predetermined criterion comprises at least one threshold frequency, determining whether at least one characteristic of the detected wind satisfies at least one predetermined criterion comprises determining a frequency of gusts of the detected wind and determining whether the determined frequency exceeds the threshold frequency, and the indication is based on whether the determined frequency of gusts exceeds the threshold frequency. 
     An embodiment having at least one feature of the method of any of the previous paragraphs includes controlling operation of the elevator system based on the provided indication. 
     The various features and advantages of at least one disclosed example embodiment 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 
         FIG.  1    schematically illustrates selected portions of an example embodiment of an elevator system. 
         FIG.  2    is a flow chart diagram summarizing an example elevator hoistway wind monitoring method. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of this invention facilitate reducing or minimizing rope sway in an elevator system by monitoring wind in a hoistway and providing an indication of a characteristic of the detected wind, an indication of how the detected wind can affect the elevator system, or both. The indication is useful to control the elevator system in a way that addresses a sway-inducing effect of the wind. 
       FIG.  1    schematically illustrates selected portions of an elevator system  20  situated within a hoistway  22  in a building  24 . An elevator car  26  and a counterweight  28  are suspended by traction ropes  30 , such as round steel ropes or flat belts. A machine and traction sheave  32  selectively causes movement of the traction ropes  30  to control the movement and position of the elevator car  26 . The machine and traction sheave  32  are located within a machine room  34  in the illustrated example embodiment. 
     A compensation assembly includes compensation ropes  36  and a tie-down mechanism including a compensation sheave  38 . The compensation ropes  36  are suspended beneath the elevator car  26  and the counterweight  28 . The compensation assembly facilities maintaining tension on the traction ropes  30  to ensure the desired traction necessary for controlling the movement and position of the elevator car  26 . 
     The hoistway  22  includes a plurality of doors  40 ,  42  that allow passengers to board or exit the elevator car  26  when the elevator car is at the corresponding landing. In a high rise building there will be many more doors than those which are illustrated for discussion purposes. The hoistway doors  40 ,  42  introduce a possibility for wind conditions to develop within the hoistway  22  that can have an adverse effect on the elevator system  20 . In many tall or high rise buildings, there is a significant temperature difference between the upper portion and lower portion of the hoistway  22 . This gives rise to a stack effect or chimney effect and significant upward airflow or wind within the hoistway. For example, when it is cold outside and the door  40  is open, the stack effect results in air moving as schematically shown by the arrows  44  into and toward the top of the hoistway  22 . In some situations, such airflow can have a wind speed of up to 30 meters per second (80 miles per hour). 
     Wind conditions within the hoistway  22  can have a significant effect on the compensation ropes  36 , the traction ropes  30  or both. Such rope sway can be problematic. The elevator system  20  includes a monitoring assembly for monitoring wind conditions within the hoistway  22 . A wind detector  50  detects air flow or wind within the hoistway  22  and provides an output regarding the detected wind. In the illustrated example embodiment shown in  FIG.  1   , the detector  50  is situated in the machine room  34  near an opening through which the traction ropes  30  pass as they move between the hoistway  22  and the machine room  34 . Some embodiments include at least one wind detector  50  situated within the hoistway  22 . Some example embodiments include multiple wind detectors  50  situated in various locations along the hoistway  22 . 
     The detector  50  in the illustrated example embodiment comprises an anemometer. The output of the wind detector  50  in this example indicates a speed of the detected wind. The output of the example detector  50  also indicates a frequency of wind gusts, which is a number of gusts of wind over time. 
     In the example embodiment of  FIG.  1   , the wind detector  50  communicates with a gateway  52  that provides the detector output to a processor  54 . In some embodiments, the processor  54  is located remotely from the elevator system  20  and the building  24 . In other embodiments, the processor  54  is situated within or near the building  24 . The processor  54  may be incorporated as part of an elevator controller that controls operation of the elevator system  20  or be a separated computing device as schematically illustrated. 
     The processor  54  receives the output from the wind detector  50  and determines whether at least one characteristic of the detected wind satisfies at least one predetermined criterion that corresponds to an effect of wind in the hoistway  22  on the elevator system  20 . The processor  54  is configured to provide an indication of the satisfied criterion, the effect of detected wind on the elevator system, or both. 
     In the example embodiment shown in  FIG.  1   , a plurality of detected gusts of wind  56  are represented by the output from the wind detector  50 . The processor  54  determines whether an amplitude or magnitude of any of the detected wind gusts exceeds a first threshold  58 , a second threshold  60  or a third threshold  62 . The different thresholds correspond to different effects that wind in the hoistway  22  can have on the elevator system  20 , such as inducing rope sway in the compensation ropes  36 , the traction ropes  30 , or both. The processor  54  in this embodiment also determines a frequency of the wind gusts and an amount of time that a detected wind condition exists. 
       FIG.  2    is a flowchart diagram  70  that summarizes an example approach of monitoring and controlling the elevator system  20  based on information regarding wind in the hoistway  22 . At  72 , the wind detector  50  detects wind in the hoistway  22 . At  74 , the processor  54  determines whether at least one characteristic of the detected wind satisfies a first criterion. Different characteristics and different criteria may be used in different embodiments. 
     In an example embodiment, the processor  54  determines whether the wind speed exceeds a first wind speed threshold, such as the threshold  58  shown in  FIG.  1   . In such embodiments, a first wind speed threshold is the first criterion and the wind speed is the characteristic of interest. 
     The processor  54  in some embodiments also determines whether a frequency of wind gusts exceeds a frequency threshold, which may be a first frequency threshold when considered as part of the determination made at  74  in  FIG.  2   . 
     Some example processors  54  determine an amount of time during which a detected wind condition exists and the first criterion considered at  74  includes a threshold amount of time during which the wind condition exists. 
     Different combinations of wind speed, frequency and duration may have different effects on the compensation ropes  36 , the traction ropes  30 , or both. Given this description and the arrangement of a particular elevator system, those skilled in the art will be able to determine an appropriate algorithm to be used by the processor  54  for determining when a wind condition exists in the hoistway  22  that has the potential for inducing rope sway. For example, empirical data can be collected to identify particular wind conditions that induce rope sway in particular buildings or particular elevator system configurations. Such data can be used to develop an appropriate algorithm or decision matrix to be implemented by the processor  54 . 
     If the wind detected at  72  does not satisfy the first criterion at  74 , the process continues at  72 . When the first criterion is satisfied, the processor  54  determines at  76  whether at least one characteristic of the detected wind satisfies a second criterion. Considering wind speed as an example characteristic of the detected wind, the second criterion corresponds to a second wind speed threshold that is higher than the first wind speed threshold considered at  74 . If the detected wind does not satisfy the second criterion at  76 , then the processor  54  provides an indication of a first wind condition at  78 . 
     When the detected wind satisfies the second criterion at  76 , the processor  54  determines whether at least one characteristic of the wind satisfies a third criterion at  80 . For example, the third criterion is a third wind speed threshold that is higher than the second wind speed threshold. When the second criterion was satisfied but the third was not, the processor  54  provides an indication of a second wind condition at  82 . In the event that the third criterion is also satisfied, the processor  54  provides an indication of a third wind condition at  84 . 
     Considering the example of  FIG.  1   , the indication of the first wind condition provided at  78  in  FIG.  2    corresponds to the processor  54  determining that the amplitude or magnitude of the detected wind meets or exceeds the first threshold  58 . In some embodiments, the indication of a first wind condition having a wind speed exceeding a first wind speed threshold provides information to an elevator service company or an automated elevator monitoring system regarding a condition in the hoistway  22  that requires attention or monitoring because the wind condition is such that it could lead to undesired rope sway. 
     The indication of a second wind condition provided at  82  in  FIG.  2    corresponds to the processor  54  determining that the magnitude or amplitude of the detected wind speed exceeds the second wind speed threshold  60 . In some embodiments, the second wind speed threshold  60  corresponds to a wind speed that will cause at least some rope sway. The second indication provides information that the operation of the elevator system  20  should be adjusted, such as slowing down the speed of movement of the elevator car  26  to compensate for the rope sway that is expected based on the detected wind condition. The indication of the second wind condition in some embodiments comprises a command signal that is provided to the drive of the elevator system  20  to slow down operation of the machine and traction sheave  32  and the corresponding speed of the elevator car  26 . 
     In the example embodiment under consideration, the third wind condition indication provided at  84  corresponds to the wind speed exceeding the third wind speed threshold  62 . In this example embodiment, when the detected wind speed exceeds the third threshold  62 , that corresponds to wind speeds within the hoistway  22  that are high enough to induce an amount of rope sway that requires shutting down the elevator system  20  at least temporarily until the wind subsides. In some embodiments, the indication of the third wind condition includes a command to move the elevator car  26  to a predetermined position within the hoistway  22 , which is considered a non-resonant location to avoid a resonant frequency of rope sway, and shutting down the elevator system. 
     In some embodiments, the criteria considered by the processor  54  are considered in relationship with each other. For example, the wind speed and frequency of wind gusts may satisfy different criteria depending on the combination of those characteristics. A lower wind speed at a higher frequency may have one effect on likely rope sway while a higher wind speed at a lower frequency may have the same effect. The processor  54  in some embodiments is suitably programmed or otherwise configured to take into account multiple criteria and multiple characteristics of the detected wind, such as wind speed, frequency of gusts and wind duration for purposes of determining what type of indication to provide for purposes of controlling the elevator system  20  when that is appropriate or necessary. 
     For example, a single burst of a relatively high speed wind introduced through the door  40  near a bottom of the hoistway  22  will impact at least the compensation ropes  36 . A single impact may have some effect on the compensation ropes  36  without introducing a significant amount of rope sway. Over time, however, with continued exposure to such wind, the compensation ropes  36  may being to sway in a substantial way. Similarly, a number of gusts of such wind over time at certain frequencies will introduce a greater likelihood of undesired rope sway. The processor  54  is configured to utilize an algorithm or decision matrix that includes a variety of combinations of characteristics of the detected wind and to provide an appropriate indication that facilities controlling the elevator system  20  in a manner that reduces or minimizes rope sway or other negative effects that would otherwise result from the detected wind condition in the hoistway  22 . 
     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.