Safety method and elevator drive system for elevator system comprising reduced bumper

Abstract

The invention relates to a safety method for an elevator system (100) comprising a reduced buffer (118a, 118b). The method includes detecting (210) a reduced braking force of the traction mechanical braking device, and in response to detecting the reduced braking force, adjusting (220) at least one limiting parameter that limits an elevator movement, where the elevator movement represents a movement of an elevator car (102) of the elevator system (100). The invention also relates to an elevator drive system (122) and an elevator system (100).

Description

Technical Field

[0001] This invention generally relates to the technical field of elevator systems. In particular, this invention relates to the safety of elevator systems. Background Technology

[0002] An elevator system includes an elevator car configured to travel between floors along an elevator shaft, an elevator control system, and a traction machinery system. The elevator car is driven by the traction machinery system via traction ropes that run through a traction sheave of the traction machinery system. The elevator control system includes a drive system for controlling the motors of the traction machinery system (e.g., motor power feed, motor speed, and motor torque) to move the elevator car along the elevator shaft. The drive system generates, for example, at least one drive curve, such as a speed curve and / or a torque curve, and drives the elevator car according to the generated drive curve.

[0003] Elevator systems also include safety devices, such as buffers, which are arranged in the pit of the elevator shaft to mitigate the coming to a stop by absorbing the kinetic energy of the elevator car when it attempts to pass the bottom floors and move towards the pit. Additionally, if the elevator car attempts to pass the top floors and move towards the top of the elevator shaft, a separate buffer can be installed in the pit to mitigate the coming to a stop by absorbing the kinetic energy of the counterweight. Typically, the size of the buffer is determined based on the nominal speed of the elevator car. In other words, the rated impact speed of the buffer usually corresponds to the nominal speed of the elevator car. In some cases, instead of a typical buffer, the elevator system may include a reduced-size buffer with a reduced height. The reduced-size buffer can be designed such that its rated impact speed is lower than the nominal speed of the elevator car.

[0004] The elevator system includes an additional traction mechanical brake, which can be used to stop the elevator car from moving unintended. Furthermore, the elevator system may include an overspeed regulator, which electrically actuates the traction mechanical brake to stop the elevator car if the elevator car's speed exceeds the overspeed limit.

[0005] Different safety functions of an elevator system may require different braking forces from the traction mechanical brakes to stop the elevator car. For example, in response to the detection that the elevator car speed exceeds the overspeed limit, with a conventional buffer (i.e., a non-reduced buffer), the braking force sufficient to slow the elevator car is adequate because it is not important whether the elevator car hits (i.e., collides with) the buffer, as the buffer's rated impact speed corresponds to the elevator car's nominal speed. However, with a reduced buffer, a higher braking force is required because the buffer's rated impact speed is lower than the elevator car's nominal speed.

[0006] Typically, the elevator system's drive system is used to monitor the braking force of the traction mechanical brake. Traditionally, the elevator system needs to stop service in response to the drive system detecting a decrease in the braking force of the traction mechanical brake. Summary of the Invention

[0007] The following is a simplified summary of the invention to provide a basic understanding of some aspects of various embodiments of the invention. This summary is not a broad overview of the invention. It is neither intended to identify key or essential elements of the invention nor to depict its scope. The following summary presents only some concepts of the invention in a simplified form, serving as a prelude to a more detailed description of exemplary embodiments of the invention.

[0008] The object of this invention is to provide a method and an elevator drive system for an elevator system including a reduced buffer, as well as an elevator system. Another object of this invention is that the elevator system and elevator drive system, including the elevator system and elevator system including a reduced buffer, allow operation of the elevator system to continue when a reduction in the braking force of the traction mechanical braking device is detected.

[0009] The object of the present invention is achieved by the method, elevator drive system, and elevator system as defined by the respective independent claims.

[0010] According to a first aspect, a safety method for an elevator system including a reduced buffer is provided, wherein the method includes: detecting a reduced braking force of a traction mechanical braking device, and adjusting at least one limiting parameter that limits elevator movement in response to detecting the reduced braking force, wherein the elevator movement represents the movement of an elevator car in the elevator system.

[0011] Reduced braking force can be detected during condition monitoring tests of the traction machinery braking device.

[0012] Alternatively or additionally, detecting reduced braking force may include detecting that the braking force of at least one traction mechanical brake of the traction mechanical braking system has decreased below a predetermined braking force limit.

[0013] Adjusting at least one limiting parameter may include reducing the overspeed limit of the elevator car.

[0014] The overspeed limit of the elevator car can be reduced to the rated impact speed of the buffer or to the speed value corresponding to the reduced braking force.

[0015] Alternatively or additionally, adjusting at least one limiting parameter may include reducing the limit value of the Emergency Terminal Speed ​​Limiting (ETSL) device of the elevator system.

[0016] The limits of the ETSL device can be reduced to the rated impact speed of the buffer or to the limit corresponding to the reduced braking force.

[0017] Alternatively or additionally, adjusting at least one limiting parameter may include reducing the maximum speed of the elevator speed curve.

[0018] The maximum speed of the elevator speed curve can be reduced to the rated impact speed of the buffer or to the maximum speed value corresponding to the reduced braking force.

[0019] According to a second aspect, an elevator drive system including a reduced buffer is provided, wherein the elevator drive system includes: at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured together with the at least one processor to cause the elevator drive system to perform: detecting a reduced braking force of a traction mechanical braking device, and adjusting at least one limiting parameter that limits elevator movement in response to detecting the reduced braking force, wherein the elevator movement represents the movement of the elevator car of the elevator system.

[0020] Reduced braking force can be detected during condition monitoring tests of the traction machinery braking device.

[0021] Alternatively or additionally, the detection of reduced braking force may include the elevator drive system being configured to detect that the braking force of at least one traction mechanical brake of the traction mechanical braking device has decreased to below a predetermined braking force limit.

[0022] Adjustment of at least one limiting parameter may include configuring the elevator drive system to reduce the overspeed limit of the elevator car.

[0023] The overspeed limit of the elevator car can be reduced to the rated impact speed of the buffer or to the speed value corresponding to the reduced braking force.

[0024] Alternatively or additionally, adjusting at least one limiting parameter may include: configuring the elevator drive system to reduce the limit value of the Emergency Terminal Speed ​​Limit (ETSL) device of the elevator system.

[0025] The limits of the ETSL device can be reduced to the rated impact speed of the buffer or to the limit corresponding to the reduced braking force.

[0026] Alternatively or additionally, adjusting at least one limiting parameter may include configuring the elevator drive system to reduce the maximum speed of the elevator speed curve.

[0027] The maximum speed of the elevator speed curve can be reduced to the rated impact speed of the buffer or to the maximum speed value corresponding to the reduced braking force.

[0028] According to a third aspect, an elevator system is provided, comprising: an elevator car arranged to travel along an elevator shaft; a reduced buffer arrangement including a reduced buffer; a traction mechanical braking device including at least two traction mechanical brakes; and an elevator drive system as described above.

[0029] Various exemplary and non-limiting embodiments of the invention (with regard to structure and operation) and their additional objects and advantages will be best understood from the following description of specific exemplary and non-limiting embodiments when read in conjunction with the accompanying drawings.

[0030] The verbs “comprising” and “including” are used herein as open-ended restrictions, neither excluding nor requiring the presence of any unlisted features. Unless otherwise expressly stated, the features recited in the dependent claims may be freely combined with each other. Furthermore, it should be understood that the use of “a” or “an,” i.e., the singular form, throughout the document does not exclude a plurality. Attached Figure Description

[0031] The embodiments of the invention are illustrated in the accompanying drawings by way of example and not limitation.

[0032] Figure 1 An example of an elevator system is illustrated schematically.

[0033] Figure 2 An example of a safety method for an elevator system is illustrated schematically.

[0034] Figure 3 Another example of this method is illustrated schematically.

[0035] Figure 4 An example of a component of an elevator drive system is shown schematically. Detailed Implementation

[0036] Figure 1An example of an elevator system 100 is schematically shown. The elevator system 100 includes an elevator car 102, a counterweight 108, an elevator traction mechanism, a reduced-size buffer device, and an elevator control system 110. The elevator car is configured to travel along respective elevator shafts 104 between multiple floors (i.e., landings) 106a-106n. The elevator system 100 can also form elevator groups, i.e., groups of two or more elevator cars 102, each traveling along a separate elevator shaft 104 configured as unit operations serving the same landings 106a-106n. The elevator traction mechanism is configured to drive the elevator car 102 along the elevator shaft 104 between floors 106a-106n. The elevator traction mechanism includes an electric motor and a traction sheave 112 for lifting the elevator car 102. The elevator traction mechanism also includes a traction mechanical braking device, which comprises at least two traction mechanical brakes 114a and 114b, which act directly on the traction sheave 112 to stop any unintended movement of the elevator car 102. Figure 1 In the example, the elevator traction mechanism braking device includes two traction mechanism brakes 114a and 114b. However, the traction mechanical braking device may also include more than two traction mechanical brakes. Furthermore, the elevator system 100 may include an overspeed regulator for monitoring the speed of the elevator car 102. For clarity, Figure 1 The overspeed regulator is not shown. If the speed of the elevator car 102 exceeds the overspeed limit, the overspeed regulator can electrically actuate the traction mechanical brakes 114a and 114b to stop the movement of the elevator car 102. For illustrative purposes, Figure 1 Only the traction sheave 112 and traction brakes 114a and 114b of the elevator traction mechanism are shown. The elevator car 102, the elevator traction mechanism, and the counterweight 108 are interconnected via a traction rope assembly 116, which is wired via the traction sheave 112 and multiple pulleys. For clarity, these pulleys are shown in... Figure 1Not shown. As the traction sheave 112 rotates, the elevator car 102 and counterweight 108 are moving. The traction rope assembly 116 includes at least one traction rope or belt. The reduced buffer assembly includes a reduced car buffer 118a and a reduced counterweight buffer 118b. The reduced car buffer 118a is arranged in the pit of the elevator shaft 104 to mitigate the stopping of the elevator car 102 by absorbing its kinetic energy when the elevator car 102 attempts to pass the bottom floor 106a towards the pit. The reduced counterweight buffer 118b is arranged in the pit of the elevator shaft 104 to mitigate the stopping of the counterweight 108 by absorbing its kinetic energy when the elevator car 102 attempts to run towards the top floor 106n of the elevator shaft 104. Compared to the height of conventional buffers, the heights of the reduced buffers 118a and 118b are reduced, the dimensions of which are determined based on the nominal speed of the elevator car 102. The reduced dimensions of the buffers 118a and 118b can, for example, be designed such that the rated impact speed of the buffers 118a and 118b is lower than the nominal speed of the elevator car 102. The rated impact speed of the buffers 118a and 118b represents the maximum permissible speed of the corresponding elevator body (depending on the elevator car 102 or counterweight 108 of the buffers 118a and 118b), at which the elevator body is allowed to impact the buffers 118a and 118b such that the buffers 118a and 118b can still mitigate the coming to a stop of the corresponding elevator bodies 102 and 108.

[0037] The elevator control system 110 is configured to control at least the operation of the elevator system 100. The elevator control system 110 may be located within the machine room 120 (e.g., Figure 1(as shown in the example) or located at one of floors 106a-106n, for example in a machine room-less elevator system. The elevator control system 110 is communicatively coupled to other entities of the elevator system 100. Communication between the elevator control system 110 and other entities of the elevator system 100 can be based on one or more known wired or wireless communication technologies. The implementation of the elevator control system 110 can be accomplished as an independent control entity or as a distributed control environment among multiple independent control entities (e.g., multiple servers), thereby providing distributed control resources. The elevator control system 110 includes an elevator drive system 122 for controlling the motors of the elevator traction machinery (e.g., motor power feed, motor speed, and motor torque) to move the elevator car 102 along the elevator shaft 104. The elevator drive system 122 can, for example, generate at least one elevator drive curve, such as an elevator speed curve and / or torque curve, and drive the elevator car 102 according to the generated at least one drive curve. The elevator system 100 may also include one or more known elevator-related entities, such as user interface devices, elevator doors, and / or safety circuits and devices, etc., which are not explicitly shown in the examples. Figure 1 As shown in the image.

[0038] When using reduced buffers 118a, 118b, an Emergency Terminal Speed ​​Limiting (ETSL) function is required according to elevator standards to implement Emergency Terminal Speed ​​Reduction (ETS). To implement the ETSL function, elevator system 100 includes at least one ETSL device 124a, 124b arranged to each terminal area of ​​elevator shaft 104. ETSL devices 124a, 124b monitor the speed of elevator car 102 at the terminal areas of elevator shaft 104. The speed monitoring of elevator car 102 by ETSL devices 124a, 124b is independent of the speed control of elevator system 100 performed by elevator drive system 122. The terminal areas (i.e., terminal zones) of elevator shaft 104 are the bottom terminal area (i.e., the pit of elevator shaft 104) and the top terminal area. In other words, elevator system 100 includes at least one ETSL device 124a, 124b arranged to the bottom terminal area of ​​elevator shaft 104 and at least one ETSL device 124a, 124b arranged to the top terminal area of ​​elevator shaft 104. The number of ETSL devices 124a, 124b arranged in each terminal area of ​​elevator shaft 104 can depend on the nominal speed of elevator car 102. According to a non-limiting example, when the nominal speed of elevator car 102 is 2.5 m / s, one ETSL device 124a, 124b can be arranged in each terminal area of ​​elevator shaft 104. According to another non-limiting example, when the nominal speed of elevator car 102 is 4.5 m / s, three ETSL devices 124a, 124b can be arranged in each terminal area of ​​elevator shaft 104. Figure 1 In the example, one ETSL device 124a is arranged in the bottom terminal region of the elevator shaft 104, and one ETSL device 124b is arranged in the top terminal region of the elevator shaft 104. However, the elevator system 100 may also include more than one ETSL device 124a, 124b arranged in each terminal region of the elevator shaft 104. The location of at least one ETSL device 124a, 124b in the terminal region of the elevator shaft 104 (e.g., distance from terminal floors 106a, 106n) may depend on the nominal speed of the elevator car 102. Each ETSL device 124a, 124b is assigned a limit value, i.e., a speed limit value. The limit value of the ETSL devices 124a, 124b, i.e., the limit value assigned to the ETSL devices 124a, 124b, is the maximum permissible speed of the elevator car 102 in the terminal region of the elevator shaft 104. If the speed of elevator car 102 exceeds the limit value of ETSL devices 124a and 124b at their locations, ETSL devices 124a and 124b disconnect the safety circuit of elevator system 100 to remove power from the electric motor and traction mechanical brakes 114a and 114b. Actuation of ETSL devices 124a and 124b causes an emergency stop of elevator car 102. The limit values ​​of ETSL devices 124a and 124b may depend on factors of elevator system 100, such as the design of buffers 118a and 118b, the nominal speed of elevator car 102, the moving mass, and / or the terminal area of ​​elevator shaft 104. ETSL devices 124a and 124b and the ETSL function are a final backup in case normal terminal deceleration fails to slow elevator car 102 at the terminal area of ​​elevator shaft 104.

[0039] Next, through reference Figure 2 Examples of safety methods for elevator system 100 including reduced buffers 118a, 118b are described. Figure 2 The safety method is illustrated schematically in a flowchart. This method is executed by the elevator drive system 122 of the elevator system 100.

[0040] In step 210, the elevator drive system 122 detects a decrease in braking force of the traction mechanical brake. For example, the decrease in braking force can be detected during a condition monitoring test of the traction mechanical brake. If traction mechanical brakes 114a, 114b are used in the Unintended Car Movement Protection (UCMP) solution of the elevator system 100 to stop the unintended movement of the elevator car 102, then periodic condition monitoring tests of the traction mechanical brakes 114a, 114b are required according to elevator standards. Condition monitoring tests of the traction mechanical brake can be performed, for example, daily. According to an example, condition monitoring tests can include monitoring the braking capability of the traction mechanical brake by monitoring the braking force of each traction mechanical brake 114a, 114b. For example, in a traction mechanical brake system including two traction mechanical brakes 114a, 114b, each traction mechanical brake 114a, 114b is designed to individually stop and hold an empty elevator car 102 stationary. The braking force may gradually decrease, for example, due to dirt, grease, or other contaminants on the brake pads of the main mechanical brakes 114a and 114b or on the surface of the traction wheel 112. For example, oil on the surface of the traction wheel 112 may cause a decrease in the braking force of the traction mechanical device. To detect the decrease in braking force of the traction mechanical brake device, it is sufficient to detect the decrease in braking force of at least one of the traction mechanical brakes 114a and 114b. In other words, if a decrease in braking force is detected in at least one of the traction mechanical brakes 114a and 114b, a decrease in the braking force of the entire traction mechanical brake device is detected. Detecting a decrease in braking force may, for example, include detecting that the braking force of at least one of the traction mechanical brakes 114a and 114b has decreased below a predetermined braking force limit. When the elevator car 102 is empty, stationary, and the elevator doors are closed, a condition monitoring test of the traction mechanical brake device is performed. In the condition monitoring test of the traction mechanical brake system, one traction mechanical brake 114a, 114b is lifted (i.e., opened) at a time, and the motion representing the rotation of the motor is monitored. The motion can be monitored based on movement data obtained from a positioning device. The positioning device can be, for example, a motor encoder, a door zone sensor, or any other sensor device capable of acquiring motion data. According to an example, during the lifting of one of the traction mechanical brakes 114a, 114b, the detection of only the motion representing the rotation of the motor (i.e., the detection that a single traction mechanical brake 114a, 114b cannot keep the empty elevator car 102 stationary as required) can be used as an indication that the braking force of the traction mechanical brakes 114a, 114b is below a predetermined braking force limit, i.e., the braking force of the traction mechanical brakes 114a, 114b is reduced, and therefore the braking force of the entire traction mechanical brake system is also reduced.According to another example, in the absence of detected motion representing the rotation of the motor during the lifting of one of the traction mechanical brakes 114a, 114b (i.e., the elevator car 102 remains stationary), the condition monitoring test may further include the elevator drive system 112 gradually actuating the motor to provide torque against the individual traction mechanical brakes 114a, 114b. The provided torque may be obtained, for example, from the motor control system (e.g., calculated based on the motor current). When motion representing the rotation of the motor is detected, the braking force of the individual traction mechanical brakes 114a, 114b may be defined (e.g., calculated or estimated) based on the additional torque provided at the moment the motion is detected. In this example, if the defined braking force of at least one traction mechanical brake 114a, 114b is below a predetermined braking force limit, the braking force of the traction mechanical brakes 114a, 114b is reduced, and therefore the braking force of the entire traction mechanical braking system is also reduced. In addition to detecting the reduced braking force, in this example, the amount of the reduced braking force may be defined, i.e., the amount by which the braking force falls below the braking force limit. According to yet another example, the reduced braking force can be detected by monitoring the force generated by each traction mechanical brake 114a, 114b. The force generated by each traction mechanical brake 114a, 114b can be monitored, for example, by one or more force sensors. In this example, if the monitored braking force of at least one traction mechanical brake 114a, 114b is lower than a predetermined braking force limit, the braking force of said traction mechanical brake 114a, 114b is reduced, and therefore the braking force of the entire traction mechanical braking device is also reduced. In addition to detecting the reduced braking force, in this example, the amount of the reduced braking force can be defined.

[0041] At step 220, in response to the detection of reduced braking force at step 210, the elevator drive system 122 adjusts at least one limiting parameter that restricts elevator movement. This allows the operation of the elevator system 100 to continue with limited performance despite the detection of reduced braking force. In other words, when a reduced braking force of the traction mechanical brake is detected, for example while waiting for repair of the traction mechanical brake, the elevator system 100 does not need to stop operating. This, in turn, reduces the downtime of the elevator system 100. Elevator movement refers to the movement of the elevator car 102. Elevator movement can be, for example, the movement of the elevator car 102, the movement of the counterweight 108, and / or any other movement caused by an electric motor to drive the elevator car 102.

[0042] Figure 3 It is illustrated in a more detailed manner. Figure 2 The flowchart. Specifically, step 220 starts from... Figure 3 It became clear.

[0043] Adjusting at least one limiting parameter at step 220 may include the elevator drive system 122 reducing the overspeed limit of the elevator car 102 at step 310. In other words, at least one limiting parameter may include the overspeed limit of the elevator car 102, and the elevator drive system 122 may adjust the overspeed limit. According to an example, the overspeed limit of the elevator car 102 may be reduced to the rated impact speed of the buffers 118a, 118b. When the overspeed limit is reduced to the rated impact speed of the buffers 118a, 118b, the amount of the reduced braking force does not need to be known. According to another example, if the amount of the reduced braking force has been defined, the overspeed of the elevator car 102 may be reduced to a speed value corresponding to the reduced braking force. The speed value corresponding to the reduced braking force is lower than the initial overspeed value (i.e., the overspeed value before reduction) but higher than the rated impact speed of the buffers 118a, 118b. Reducing the overspeed limit to a speed value corresponding to the reduced braking force allows the elevator car 102 to be driven at a speed higher than the rated impact speed of the buffers 118a, 118b, but the speed of the elevator car 102 can still be reduced to the rated impact speed of the buffers, regardless of the reduced braking force.

[0044] Alternatively or additionally, adjusting at least one limiting parameter at step 220 may include the elevator drive system 122 reducing the limit values ​​of ETSL devices 124a, 124b at step 320. In other words, at least one limiting parameter may alternatively or additionally include the limit values ​​of ETSL devices 124a, 124b, and the elevator drive system 122 may adjust the limit values ​​of ETSL devices 124a, 124b. Each ETSL device 124a, 124b may include an input device (e.g., one or more input devices) for receiving the adjusted limit value and a processing device (e.g., a processing unit including one or more processors) for performing the adjustment of the limit value. Each ETSL device 124a, 124b may also include a memory device, such as a memory cell including one or more memories, for storing the reduced limit value. For example, ETSL devices 124a, 124b may be a switching device that includes the aforementioned ETSL devices and is capable of monitoring the speed of the elevator car 102. When a reduced braking force is detected, in order to slow the elevator car 102 by sufficiently actuating the ETSL devices 124a and 124b from an angle determined by the reduced dimensions of the buffers 118a and 118b, the limiting values ​​of the ETSL devices 124a and 124b need to be reduced. The required reduction in the limiting values ​​of the ETSL devices 124a and 124b can depend on the amount of the reduced braking force. According to an example, the limiting values ​​of the ETSL devices 124a and 124b can be reduced to the rated impact speed of the buffers 118a and 118b. When the limiting values ​​of the ETSL devices 124a and 124b are reduced to the rated impact speed of the buffers 118a and 118b, the amount of the reduced braking force does not need to be known. When actuated (i.e., when the speed of the elevator car 102 exceeds the reduction limit of the ETSL device), the ETSL devices 124a and 124b stop the elevator movement by disconnecting the safety circuit to remove power from the electric motor and traction mechanical brakes 114a and 114b, such that the rated impact speed of the buffers 118a and 118b is not exceeded. According to another example, if the amount of reduced braking force has been limited, the limit value of the ETSL devices 124a and 124b can be reduced to a limit value corresponding to the reduced braking force. The limit value corresponding to the reduced braking force is lower than the initial limit value (i.e., the limit value before reduction) but higher than the rated impact speed of the buffers 118a and 118b.

[0045] Alternatively or additionally, adjusting at least one limiting parameter at step 220 may include the elevator drive system 122 adjusting the elevator speed curve at step 330. More specifically, adjusting at least one limiting parameter at step 220 may include the elevator drive system 122 reducing the maximum speed of the elevator speed curve. In other words, at least one limiting parameter may alternatively or additionally include the maximum speed of the elevator speed curve, and the elevator drive system 122 may adjust the maximum speed of the elevator speed curve. According to an example, the maximum speed of the elevator speed curve may be reduced to the rated impact speed of the buffers 118a, 118b. When the maximum speed of the elevator speed curve is reduced to the rated impact speed of the buffers 118a, 118b, the amount of the reduced braking force need not be known. According to another example, if the amount of the reduced braking force has been defined, the maximum speed of the elevator speed curve may be reduced to a maximum speed value corresponding to the reduced braking force. The maximum speed value corresponding to the reduced braking force is lower than the initial maximum speed (i.e., the maximum value before reduction), but higher than the rated impact speed of the buffers 118a, 118b. Reducing the maximum speed of the elevator speed curve to the maximum speed value corresponding to the reduced braking force allows the elevator car 102 to be driven at a speed higher than the rated impact speed of the buffers 118a and 118b, but the speed of the elevator car 102 can still be slowed down to the rated impact speed of the buffers, regardless of the reduced braking force.

[0046] Figure 4Examples of components of an elevator drive system 122 are schematically shown. The elevator drive system 122 may include: a processing unit 410 including one or more processors, a memory unit 420 including one or more memories, a communication unit 430 including one or more communication devices, and a possible user interface (UI) unit 440. The aforementioned components may be communicatively connected to each other, for example, via a communication bus. The memory unit 420 may store and maintain portions and data of a computer program (code) 425. The computer program 425 may include instructions that, when executed by the processing unit 410 of the elevator drive system 122, cause the processing unit 410 and thus the elevator drive system 122 to perform desired tasks, such as one or more of the method steps described above. Therefore, the processing unit 410 may be arranged to access the memory unit 420 and retrieve any information from and store any information in the memory unit 420. For clarity, the term "processor" herein refers to any unit suitable for processing information and controlling the operation of the elevator drive system 122, as well as other tasks. These operations may also be implemented using a microcontroller solution with embedded software. Similarly, memory unit 420 is not limited to a certain type of memory, but any type of memory suitable for storing the described multiple pieces of information can be applied in the context of this invention. Communication unit 430 provides one or more communication interfaces for communicating with any other unit (e.g., electric motor, traction mechanical brakes 114a, 114b, at least one ETSL device 124a, 124b, one or more databases) and / or with any other unit. User interface unit 440 may include one or more input / output (I / O) devices for receiving user input and output information, such as buttons, keyboards, touchscreens, microphones, speakers, displays, etc. Computer program 425 may be a computer program product, which may be included in a tangible, non-volatile (non-transitory) computer-readable medium carrying the computer program code 425 embodied therein for use with a computer (i.e., elevator drive system 122).

[0047] The specific examples provided in the description above should not be construed as limiting the applicability and / or interpretation of the appended claims. Unless otherwise expressly stated, the list and groups of examples provided in the description above are not exhaustive.

Claims

1. A safety method for an elevator system (100) including reduced buffers (118a, 118b), the method comprising: The reduced braking force of the traction mechanical braking device was detected (210), and In response to the detection of the reduced braking force, at least one limiting parameter restricting the elevator movement is adjusted (220), wherein the elevator movement represents the movement of the elevator car (102) of the elevator system (100).

2. The method according to claim 1, wherein, The reduced braking force was detected during the condition monitoring test of the traction mechanical braking device.

3. The method according to any one of the preceding claims, wherein, Detecting reduced braking force includes detecting that the braking force of at least one traction mechanical brake (114a, 114b) of the traction mechanical braking device has decreased to below a predetermined braking force limit.

4. The method according to any one of the preceding claims, wherein, The adjustment (220) of the at least one limiting parameter includes reducing (310) the overspeed limit of the elevator car (102).

5. The method according to claim 4, wherein, The overspeed limit of the elevator car (102) is reduced to the rated impact speed of the buffers (118a, 118b) or to the speed value corresponding to the reduced braking force.

6. The method according to any one of the preceding claims, wherein, The adjustment (220) of the at least one limiting parameter includes reducing (320) the limit value of the Emergency Terminal Speed ​​Limit (ETSL) device of the elevator system (100).

7. The method according to claim 6, wherein, The limit value of the ETSL device is reduced to the rated impact speed of the buffers (118a, 118b) or to the limit value corresponding to the reduced braking force.

8. The method according to any one of the preceding claims, wherein, The adjustment (220) of the at least one limiting parameter includes reducing (330) the maximum speed of the elevator speed curve.

9. The method according to claim 8, wherein, The maximum speed of the elevator speed curve is reduced to the rated impact speed of the buffers (118a, 118b) or to the maximum speed value corresponding to the reduced braking force.

10. An elevator drive system (122) comprising an elevator system (100) including reduced buffers (118a, 118b), the elevator drive system (122) comprising: At least one processor (410); and At least one memory (420), the at least one memory including computer program code (425). The at least one memory (420) and the computer program code (425) are configured to, together with the at least one processor (410), enable the elevator drive system (122) to execute: Detect the reduced braking force of the traction machinery braking device, and In response to the detection of the reduced braking force, at least one limiting parameter restricting the elevator movement is adjusted, wherein the elevator movement represents the movement of the elevator car (102) of the elevator system (100).

11. The elevator drive system (122) according to claim 10, wherein, The reduced braking force was detected during the condition monitoring test of the traction mechanical braking device.

12. The elevator drive system (122) according to any one of claims 10 or 11, wherein, The detection of the reduced braking force includes: the elevator drive system (122) being configured to detect that the braking force of at least one traction mechanical brake (114a, 114b) of the traction mechanical braking device has decreased to below a predetermined braking force limit.

13. The elevator drive system (122) according to any one of claims 10 to 12, wherein, The adjustment of the at least one limiting parameter includes: the elevator drive system (122) being configured to reduce the overspeed limit of the elevator car (102).

14. The elevator drive system (122) according to claim 13, wherein, The overspeed limit of the elevator car (102) is reduced to the rated impact speed of the buffers (118a, 118b) or to a speed value corresponding to the reduced braking force.

15. The elevator drive system (122) according to any one of claims 10 to 14, wherein, The adjustment of the at least one limiting parameter includes: the elevator drive system (122) being configured to reduce the limit value of the emergency terminal speed limit (ETSL) device of the elevator system (100).

16. The elevator drive system (122) according to claim 15, wherein, The limit value of the ETSL device is reduced to the rated impact speed of the buffers (118a, 118b) or to the limit value corresponding to the reduced braking force.

17. The elevator drive system (122) according to any one of claims 10 to 16, wherein the adjustment of said at least one limiting parameter comprises: The elevator drive system (122) is configured to reduce the maximum speed of the elevator speed curve.

18. The elevator drive system (122) according to claim 17, wherein, The maximum speed of the elevator speed curve is reduced to the rated impact speed of the buffers (118a, 118b) or to the maximum speed value corresponding to the reduced braking force.

19. An elevator system (100), comprising: An elevator car (102) is arranged to travel along an elevator shaft (104); A reduced buffer device, comprising reduced buffers (118a, 118b). A traction mechanical braking device, comprising at least two traction mechanical brakes (114a, 114b); and The elevator drive system (122) according to any one of claims 10 to 18.

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