Method for releasing a safety mechanism and stall detector

Abstract

According to an aspect, there is provided a method for releasing a safety mechanism of an elevator car (206) or a counterweight of an elevator system, the elevator system comprising a stall detector (200, 300, 400) coupled to a compensating rope associated with the elevator car (206) or the counterweight and configured to detect an increased rope tension. The method comprises preventing a stall indication from the stall detector (200, 300, 400) during a rescue operation; and moving the elevator car (206) to release the safety mechanism.

Description

Technical Field

[0001] This invention relates to the field of elevator systems, and more particularly to a method for releasing a safety mechanism and a stall detector. Background Technology

[0002] An elevator car safety mechanism is a safety device that stops the elevator car when it travels at a speed exceeding the overspeed limit set for the elevator. In a typical safety mechanism arrangement, one of a pair of safety mechanisms is located on each side of the elevator car facing the guide rails. This safety mechanism is activated upon detecting overspeed to clamp the guide rails and stop the elevator car. As the elevator car moves forward, the wedging action of the safety mechanism strengthens the clamping force on the guide rails until the maximum permissible deceleration rate is reached. After stopping, the safety mechanism holds the car firmly in its position until the clamping is released by pushing the car backward from its stopped position, until the safety mechanism wedge disengages from the guide rails. In some applications, such as marine elevators, the counterweight may have its own overspeed detection and safety mechanism. In some applications, a two-way safety mechanism may be used, with overspeed limits for both upward and downward travel.

[0003] Lifting the clamping element—the elevator car or counterweight—using lifting machinery, clamping it downwards, and then releasing (i.e., releasing) the safety mechanism is straightforward. However, after clamping upwards, the elevator car or counterweight should move downwards, which may be impossible due to imbalances between the two sides of the elevator car and counterweight. For example, if the elevator car is high in the shaft, almost all the weight of the lifting ropes is on the counterweight side, and the remaining load on the car side may not be sufficient to release the clamping force of the safety mechanism. This situation is greatly aided if the elevator has compensating ropes to counteract the changing imbalance between the elevator car and the counterweight side. The compensating rope extends from the bottom of the elevator car through a tension pulley at the bottom of the shaft to the bottom of the counterweight, thus keeping the weight of the ropes balanced at all times. In cases such as clamping the elevator car upwards, the compensating rope can be used by maintenance personnel at the bottom of the shaft to pull the car down. However, entering the shaft always presents safety hazards for maintenance personnel.

[0004] Elevator stall detection is a safety measure used to monitor whether the weight of the elevator car and counterweight maintains tension in the lifting mechanism (i.e., the lifting ropes or belts). This tension is crucial for providing sufficient traction between the traction pulleys and the lifting mechanism, and for ensuring the lifting mechanism remains taut along its intended path. If stall detection indicates that the weight of the elevator car or counterweight is no longer sufficient to support the lifting mechanism, the elevator should be immediately secured until maintenance personnel identify and eliminate the cause of the stall and reset the elevator to normal operating mode.

[0005] In elevators equipped with compensating ropes, rescue operations can be performed by using lifting machinery to drive the clamping side downwards, releasing passengers from the fixed elevator car after the safety mechanism clamps them upwards: as the lifting machinery pulls the clamping side up, the compensating rope pulls it down. However, stall detection will detect an increase in tension in the compensating rope and stabilize the elevator due to the risk of stall caused by a slack hoisting rope on the clamping side.

[0006] Elevator systems including high-friction lifting components require a detection system to detect when the elevator car or its associated counterweight is ascending. This refers to a situation where the elevator car or counterweight is clamped or driven into the end buffer in the elevator shaft. In response to a sudden impact, the elevator car and / or counterweight may bounce. This can cause the ropes associated with the elevator car to loosen, causing the elevator car to eventually begin to descend due to gravity as the tension in the ropes lifting the elevator car is no longer present. For safety, the detection system shuts down the elevator machinery upon detecting a change in rope tension. Sudden and rapid movement may further trigger the elevator safety mechanisms engaged with the elevator car and preventing its movement.

[0007] To release the elevator car, it needs to move downwards so that the safety mechanism can disengage. Depending on the structure of the safety mechanism solution, this can require considerable force. Releasing the elevator car can be difficult when it has already stopped between floors, making it impossible to add weight to the car. Summary of the Invention

[0008] One objective is to provide a method and apparatus for rescue operations in elevator systems.

[0009] According to a first aspect, a method is provided for releasing a safety mechanism of an elevator car or counterweight in an elevator system, the elevator system including a stall detector coupled to a compensating rope associated with the elevator car and counterweight, and configured to be activated in response to the detection of increased rope tension. The method includes preventing a stall indication from the stall detector during a rescue operation; and moving the elevator car to release the safety mechanism.

[0010] In an exemplary embodiment, preventing stall indication from a stall detector during a rescue operation includes setting the stall detector to a rescue mode that prevents stall indication from a stall detector during a rescue operation.

[0011] In an exemplary embodiment, setting the stall detector to a rescue mode that prevents stall indication from the stall detector during a rescue operation includes locking the stall detector in place by at least one of electromechanical and electrical devices.

[0012] In an exemplary embodiment, the method may additionally or alternatively include monitoring a stall detector such that the elevator car cannot be used normally when the stall detector is locked or set to rescue mode.

[0013] In an exemplary embodiment, additionally or alternatively, moving the elevator car to release the safety mechanism includes manually moving the elevator car by pulling it down from a compensating rope.

[0014] In an exemplary embodiment, alternatively or additionally, moving the elevator car to release the safety mechanism includes using elevator machinery to move the elevator car.

[0015] In an exemplary embodiment, additionally or alternatively, a stall detector is configured in one of the steering pulley, the car pulley, and the rope termination point.

[0016] In one exemplary embodiment, preventing a stall indication from a stall detector during a rescue operation includes: the elevator safety controller receiving a stall indication from the stall detector; and overrunning a stall indication via the elevator safety controller during the rescue operation.

[0017] According to a second aspect, a stall detector is provided, which is coupled to a compensating rope associated with the elevator car and counterweight of an elevator system. The stall detector is configured to detect an increase in the rope tension of the compensating rope; and during a rescue operation, it is able to prevent the transmission of a stall indication in response to the detection, which would allow the elevator car to move to release the safety mechanism of the elevator car or counterweight.

[0018] In an exemplary embodiment, the stall detector is configured to a rescue mode that prevents the transmission of a stall indication during a rescue operation.

[0019] In an exemplary embodiment, the stall detector is configured to be locked in place during a rescue operation using at least one of an electrical or mechanical device.

[0020] In an exemplary embodiment, additionally or alternatively, a stall detector is configured in one of the steering pulley, the car pulley, and the rope termination point.

[0021] In an exemplary embodiment, additionally or alternatively, the stall detector is coupled to the swing arm.

[0022] According to a third aspect, an elevator system is provided, comprising an elevator car, a counterweight, compensating ropes associated with the elevator car and the counterweight, a safety mechanism associated with the elevator car or its counterweight, and a stall detector according to the second aspect. The elevator car is configured to be movable to release the safety mechanism.

[0023] According to a fourth aspect, an apparatus is provided for releasing a safety mechanism of an elevator car or counterweight in an elevator system, the elevator system including a stall detector coupled to a compensating rope associated with the elevator car and counterweight, and configured to detect increased rope tension. The apparatus is configured to prevent stall indication from the stall detector during a rescue operation; and to enable the elevator car to move to release the safety mechanism.

[0024] In an exemplary embodiment, the device is also configured to monitor the stall detector such that the elevator car cannot be used normally when the stall detector is locked or set to rescue mode.

[0025] In an exemplary embodiment, the device is also configured to obtain a stall indication from a stall detector and to override the stall indication during a rescue operation.

[0026] In an exemplary embodiment, the device is also configured to monitor the stall detector such that the elevator car cannot be used normally when the stall detector is locked or set to rescue mode. Attached Figure Description

[0027] The accompanying drawings illustrate embodiments of the invention to provide a further understanding of the invention and form part of this specification, and together with the specification, help to explain the principles of the invention. In the drawings:

[0028] Figure 1 A method for releasing a safety mechanism of an elevator car in an elevator system, according to an exemplary embodiment, is shown.

[0029] Figure 2A An elevator system including a device configured to detect an increase in the tension of a compensating rope, according to an exemplary embodiment, is shown.

[0030] Figure 2B A rescue method for releasing a safety mechanism of an elevator car, according to an exemplary embodiment, is shown.

[0031] Figure 3 A device arranged to have restricted movement is shown according to an exemplary embodiment.

[0032] Figure 4 A device arranged to have restricted movement is shown according to another exemplary embodiment. Detailed Implementation

[0033] The solution described below provides a method for releasing the counterweight or elevator car safety mechanism in a rescue situation.

[0034] Figure 1 A method for releasing a safety mechanism of an elevator car in an elevator system, according to an exemplary embodiment, is shown.

[0035] This method can be applied to elevator systems that include a stall detector coupled to a compensating rope associated with the elevator car and counterweight, and configured to detect increased rope tension. At point 100, a stall indication from the stall detector is prevented during a rescue operation; at point 102, the elevator car is moved to release the safety mechanism. This movement can be provided by elevator machinery configured to move the elevator car within the elevator shaft. Alternatively, movement can be provided by manually pulling down the elevator car using the compensating rope.

[0036] Figure 2A An elevator system 211 including a stall detector 200 is shown according to an exemplary embodiment. The elevator system 211 can be implemented with ropes 202, 207 of any rope ratio, such as 2:1 or 1:1.

[0037] Elevator system 211 includes a counterweight 208 and elevator machinery configured to move elevator car 206 within an elevator shaft. The machinery may include, for example, an electric motor and traction pulleys 210 for lifting elevator car 206. For illustrative purposes, in Figure 2A Only the traction pulley 210 is shown. The elevator car 206, the machinery and counterweight 208 are interconnected by lifting ropes 207 wired through multiple pulleys 201, 203A, 204A, 209 and pulley 210.

[0038] The compensating rope 202 is used in conjunction with the lifting rope 207 to eliminate the imbalance caused by the weight imbalance of the lifting rope 207, particularly in the extreme positions of the counterweight 208 and the elevator car 206, between the elevator car 206 and its counterweight side. The compensating rope 202 can be suspended below the elevator car 206 and the counterweight 208. The compensating rope 202 may include multiple pulleys 201, 203B, 204B, and 205. Ropes 202 and 207 can be implemented using any known solution, such as wire rope, belt, polyurethane-coated rope, high-friction rope made of special grease, or toothed belt.

[0039] Elevator system 211 also includes a stall detector 200. The stall detector 200 may include a monitoring device ( Figure 2A (Not shown in the image). The monitoring device can be connected to the compensating rope 202 of the elevator system 211. The monitoring device can be configured to detect changes in rope tension that indicate abnormal movement of the elevator car 206 or the counterweight 208. For example, the monitoring device can detect when the rope tension exceeds a predetermined threshold. Alternatively, the monitoring device can be configured to detect any changes in rope tension and / or the position of the stall detector 200.

[0040] Changes in rope tension can be detected, for example, by a force sensor. Alternatively, changes in rope tension can be detected using a sensor configured to detect changes in the position of the stall detector 200. Alternatively, the sensor can be configured to detect tension or a force applied in response to pulley resistance to upward movement. In an exemplary embodiment, the stall detector 200 may be constructed in a steering pulley 201 of the compensating rope 202. The steering pulley 201 may be fixed or movable, such as a tensioning pulley. Alternatively, the stall detector 200 may be constructed in at least one of the car pulleys 203, 204. The stall detector 200 may also be constructed at different locations in the elevator system 211, for example, connected to the compensating rope 202. The stall detector 200 may be configured to detect movement of the pulley associated with the stall detector 200. This movement may be substantially orthogonal to the axis of rotation of the pulley. The stall detector 200 may include a switch that opens in response to detected abnormal movement or tension, shutting off the mechanism and applying mechanical braking. In an exemplary embodiment, the stall detector 200 can move a predetermined distance before triggering the switch.

[0041] The stall detector 200 can be coupled to a fixed support. For example, one possible option is to position the stall detector 200 at either of the rope termination points 212, 213, for example, as a force sensor. Alternatively, the stall detector 200 can be movable, such that it is arranged to move in response to increased tension on the compensating rope 202. Furthermore, the stall detector 200 can be arranged to move only a predetermined distance. For example, when the elevator car 206 is released from the safety mechanism clamps by moving the counterweight upwards, this movement is also guided via the compensating rope 202 to the guide pulley 201, which includes the stall detector 200. In normal operation, the guide pulley 201 can remain stationary, i.e., it does not move upwards or downwards, and the pulley 201 can only have rotational motion. When the guide pulley 201 is fixed, or if it can only move a limited distance, its restricted upward movement indicates higher tension in the compensating rope 202. A stall detector 200 configured to the steering pulley 201 can detect increased tension and can cause the elevator to mechanically stop and activate the mechanical brake. This detection can be performed, for example, by a force sensor or by a switch activated by movement of the steering pulley 201. For example, when a certain degree of movement is reached, the steering pulley 201 can move and physically contact the switch. The elevator car 206 can remain inoperable until the stall detection conditions are reset by maintenance personnel.

[0042] Figure 2B A rescue method for releasing a safety mechanism for an elevator car 206 according to an exemplary embodiment is shown. Figure 2B The elevator system 211 shown corresponds to Figure 2AElevator system 211.

[0043] exist Figure 2B In the exemplary case shown, in response to the elevator car 206 overspeeding in the upward direction, the safety mechanism ( Figure 2B (Not shown in the image) has been engaged. The safety mechanism can be a two-way safety mechanism. To perform a rescue operation and disengage from the safety mechanism, the elevator car 206 needs to be moved downwards. Attempted downward movement of the elevator car 206 may cause tension in the compensating rope 202, which is detected by the stall detector 200. Therefore, the elevator car 206 may not move downwards using the motor, which is shut down in response to the stall detection.

[0044] Rescue operations can be enabled by preventing a stall indication from the stall detector 200 during the rescue operation. In an exemplary embodiment, the stall detector 200 can be set to rescue mode. In another exemplary embodiment, the stall detector 200 can be mechanically or electromechanically locked in place. In rescue mode, the operation of the stall detector 200 can be deactivated. Therefore, in rescue mode, although the position of the pulley may remain unchanged, the pulley associated with the stall detector 200 can still rotate. In another exemplary embodiment, the stall detector 200 can be configured such that it can move a predetermined distance, for example, vertically, before a stall detection indication. For example, the detection switch can be positioned to detect the movement of the stall detector only after the stall detector has reached a preset movement limit distance. By preventing or delaying stall detection, movement of the elevator car 206 is not prevented during the rescue operation. Therefore, the elevator can disengage itself from the clamped state in either direction.

[0045] In another example embodiment, the stall indication can be electrically bypassed. In another example embodiment, the stall indication signal can be recorded but ignored by a computer program running in a device such as an elevator safety controller. In other words, the elevator safety controller can obtain the stall indication from the stall detector and override the stall indication during a rescue operation. Additionally, in an exemplary embodiment, the elevator safety controller can be configured to monitor the stall detector such that the elevator car cannot be used normally when the stall detector is locked or set to rescue mode.

[0046] The stall detector 200 can be set to rescue mode or locked manually or automatically. Supervision may be required to lock the stall detector 200 so that the elevator car 206 cannot be used normally when the stall detector 200 is locked or in rescue mode. Remote setting, locking, and relocation operations may be useful when maintenance personnel cannot access the elevator shaft.

[0047] If the elevator car 206 is severely stuck in the upward direction, a rescue can be performed by pulling the elevator car 206 downward using the compensating rope 202. The pulling can be performed, for example, by using a separate tool such as a hoist or by moving the elevator together with the machinery. Manual pulling may require disengaging the mechanical brakes, and therefore may also require preventing the stall detector 200 from activating in this situation. The elevator car 206 can be pulled downward, for example, by using a compensating rope 202. Figure 2A The relevant arrow in the diagram indicates that the device is pulled down from rescue point 214 and released from the engagement of the safety mechanism.

[0048] The following sections will describe in detail some examples of possible implementations of the stall detector. This arrangement prevents stall detection during rescue operations by restricting the movement of the stall detector. Restricted movement may prevent the stall detector from detecting increased tension in the compensation rope when tension is introduced during a rescue operation.

[0049] Figure 3 and Figure 4 Stall detectors 300 and 400, arranged with restricted movement according to an exemplary embodiment, are shown. The exemplary embodiment enables the prevention of stall indications from the stall detectors during rescue operations by restricting the movement of the stall detectors 300 and 400. Restricted movement may prevent the stall detectors from detecting increased tension in the compensation rope when tension is induced by the rescue operation.

[0050] Stall detectors 300 and 400 can be connected to compensating ropes 302 and 402 of the elevator system. Stall detectors 300 and 400 may include monitoring devices, such as switches or sensors, to trigger safety functions in response to increased tension in the compensating ropes 302 and 402. Stall detectors 300 and 400 can be connected, for example, to guide pulleys 303 and 404 of the compensating ropes 302 and 402.

[0051] Stall detectors 300 and 400 can be arranged such that they allow some vertical movement before stall detection is performed by a sensor or switch. In an exemplary embodiment, stall detector 300 can be implemented by a swing arm 301, such as... Figure 3As shown. The swing arm 301 can be configured to suspend the stall detector 300 from the shaft wall or floor of the elevator shaft, allowing restricted movement of the stall detector 300. For example, the swing arm 301 can be arranged such that the stall detector 300 can move a predetermined distance A before the switch is activated. Because this arrangement allows the stall detector 300 to move a predetermined distance A, the switch will not be triggered immediately when the tension of the compensating rope 302 increases. This is because the stall detector 300, 400 may not detect a force exceeding a threshold limit when the steering pulley / stall detector 300 moves in response to a sensed force. When the predetermined distance A is reached, the steering pulley 303 can stop moving, and a stall indication can be provided by the stall detector 300. In an example embodiment, the movement of the stall detector 300 or the steering pulley 303 can be restricted, or the stall detector 300 or the steering pulley 303 can be locked in place to prevent stall indication from the stall detector 300 during a rescue operation. Locking can be implemented, for example, using at least one of electromechanical and electrical devices. In another exemplary embodiment, the stall detector 300 may be configured to a rescue mode that prevents stall indications from the stall detector 300 during rescue operations.

[0052] Figure 4 Another possible implementation of a support structure for a stall detector 400 according to an exemplary embodiment is shown. Figure 4 In this configuration, a stall detector 400 and an associated pulley can be arranged within a housing 401. The housing 401 may include one or more counterweights or spring elements 403 to maintain appropriate tension in the compensating rope 402. When the tension in the compensating rope 402 increases and a lifting force is applied to the pulley, the stall detector 400 and the support structure 401 begin to move upward. In other words, the stall detector and the associated pulley can move vertically. The stall detector 400 can be configured such that it only provides a stall indication after vertical movement exceeding a predetermined distance B. (See also: Regarding...) Figure 3 As discussed, in the example embodiment, the movement of the stall detector 400 or the steering pulley 404 can be restricted, or the stall detector 400 or the steering pulley 404 can be locked in place to prevent stall indication from the stall detector 400 during a rescue operation. Locking can be implemented, for example, using at least one of electromechanical and electrical devices. In another exemplary embodiment, the stall detector 400 can be configured in a rescue mode to prevent stall indication from the stall detector 400 during a rescue operation.

[0053] exist Figure 3 and 4In the diagram, the permitted movements are shown as distances A and B between the arrows. During normal operation, distances A and B can be traveled from the starting positions corresponding to the stall detectors 300 and 400 and their associated pulleys. Figure 3 and Figure 4 The center of stall detectors 300 and 400 on the left side is located at the second position. Figure 3 and Figure 4 The stall detectors 300 and 400 are located at the center of the right side of the elevator car. The stall detectors 300 and 400 can move from their initial position to a second position in response to increased tension in the compensation rope 402. During a rescue operation, the stall detectors 300 and 400 can move a predetermined distance A or B before the stall detection or monitoring device triggers a switch, while still being able to detect situations requiring activation of safety functions. For example, when the elevator car moves during a rescue operation, movement within the predetermined distances A or B may be sufficient to disengage the safety mechanism.

[0054] Although the above embodiments and examples discuss elevator cars and their associated safety mechanisms, the same principles also apply to elevator counterweights and the safety mechanisms associated with those counterweights.

[0055] Although two examples are shown of stall detectors arranged with restricted movement, other arrangements are possible. Furthermore, while steering pulleys are used as examples of what might be associated with stall detectors, any pulley used at the rope termination point or as part of the compensation rope of an elevator system could alternatively be used.

[0056] Although the essential novel features applicable to its preferred embodiments have been shown, described, and pointed out, it should be understood that various omissions, substitutions, and changes in the form and details of the described apparatus and methods can be made by those skilled in the art without departing from the spirit of this disclosure. For example, all combinations of those elements and / or method steps explicitly intended to perform substantially the same function in substantially the same manner to achieve the same result are within the scope of this disclosure. Furthermore, it should be recognized that structures and / or elements and / or method steps shown and / or described in conjunction with any disclosed form or embodiment can be incorporated as a general matter of design choice in any other disclosed or described or suggested form or embodiment. Moreover, in the claims, the device plus function clause is intended to cover structures described herein that perform the enumerated functions, covering not only structural equivalents but also equivalent structures.

[0057] The applicant hereby independently discloses each individual feature described herein, as well as any combination of two or more such features, to the extent that, based on the general knowledge of those skilled in the art, such features or combinations can be implemented according to this specification based on a common whole, regardless of whether such features or combinations of features solve any problem disclosed herein, and is not limited to the scope of the claims. The applicant notes that the disclosed aspects / embodiments may consist of any such individual feature or combination of features. In view of the foregoing description, it will be apparent to those skilled in the art that various modifications can be made within the scope of this disclosure.

Claims

1. A method for releasing an engaged safety mechanism of an elevator car (206) in an elevator system, the elevator system including stall detectors (200, 300, 400) coupled to compensating ropes (202, 302, 402) associated with the elevator car (206) and a counterweight (208) and configured to detect increased rope tension, the method comprising: Prevent stall indications from stall detectors (200, 300, 400) during rescue operations; as well as Move the elevator car (206) downward to release the engaged safety mechanism.

2. The method according to claim 1, wherein, Preventing stall indications from the stall detectors (200, 300, 400) during rescue operations includes setting the stall detectors (200, 300, 400) to a rescue mode that prevents stall indications from the stall detectors (200, 300, 400) during rescue operations.

3. The method according to claim 1, wherein, Setting the stall detectors (200, 300, 400) to a rescue mode that prevents stall indications from the stall detectors (200, 300, 400) during rescue operations includes locking the stall detectors (200, 300, 400) in place by at least one of electromechanical and electrical devices.

4. The method according to claim 2 or 3, further comprising: Monitor the stall detectors (200, 300, 400) so that when the stall detectors (200, 300, 400) are locked or set to rescue mode, the elevator car (206) cannot be used normally.

5. The method according to any one of claims 1 to 3, wherein, Moving the elevator car (206) downward to release the engaged safety mechanism includes manually moving the elevator car (206) by pulling the elevator car (206) downward from the compensating ropes (202, 302, 402).

6. The method according to any one of claims 1 to 3, wherein, Moving the elevator car (206) downward to release the engaged safety mechanism includes using elevator machinery to move the elevator car (206).

7. The method according to any one of claims 1 to 3, wherein, The stall detectors (200, 300, 400) are configured in one of the steering pulley, car pulley, and rope termination point.

8. The method according to claim 1, wherein, Preventing stall indications from stall detectors (200, 300, 400) during rescue operations includes: Stall indications are obtained from the stall detectors (200, 300, 400) via the elevator safety controller; and During the rescue operation, the elevator safety controller indicates overrun and stall.

9. A stall detector (200, 300, 400) connected to a compensating rope (202, 302, 402) associated with an elevator car (206) and a counterweight (208) of an elevator system, said stall detector (200, 300, 400) being configured as follows: The increased rope tension of the compensation rope is detected; and This prevents the transmission of a stall indication in response to the detection during a rescue operation, and the prevention allows the elevator car (206) to move downward to release the already engaged safety mechanism of the elevator car (206).

10. The stall detector (200, 300, 400) according to claim 9, wherein, The stall detectors (200, 300, 400) are configured to a rescue mode that prevents the transmission of stall indications during rescue operations.

11. The stall detector (200, 300, 400) according to claim 9, wherein, The stall detectors (200, 300, 400) are configured to be locked in place during rescue operations using at least one of electrical or electromechanical devices.

12. The stall detector (200, 300, 400) according to any one of claims 9-11, wherein, The stall detectors (200, 300, 400) are configured in one of the steering pulley, car pulley, and rope termination point.

13. The stall detector (200, 300, 400) according to any one of claims 9-11, wherein, The stall detectors (200, 300, 400) are connected to the swing arm.

14. An elevator system, comprising: Elevator car (206); Counterweight (208); Compensating ropes (202, 302, 402) associated with the elevator car (206) and the counterweight (208). Safety mechanisms associated with the elevator car (206); as well as The stall detector (200, 300, 400) according to any one of claims 9-13, wherein the elevator car (206) is configured to move downward to release the safety mechanism that has been engaged.

15. A device for releasing an engaged safety mechanism of an elevator car (206) in an elevator system, the elevator system including stall detectors (200, 300, 400) coupled to compensating ropes (202, 302, 402) associated with the elevator car (206) and a counterweight (208), the stall detectors being configured to detect increased rope tension, the device being configured to: To prevent stall indication from the stall detectors (200, 300, 400) during rescue operations; and This allows the elevator car (206) to move downwards to release the already engaged safety mechanism.

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