Overload test system

Abstract

In a first aspect, an overload test system for testing an overload mechanism of a traction system is provided. The overload test system comprises a lower frame; an upper frame configured to couple with a traction cable, wherein the upper frame is slidably connected to the lower frame; the pressure element is arranged between the upper frame and the lower frame and is used for enabling the lower frame to move relative to the upper frame; and wherein the lower frame and the upper frame comprise a channel for receiving a traction cable. In another aspect, a method for testing an overload mechanism of a traction system is provided. The method includes positioning the lower frame to be supported on a traction system; coupling the upper frame with the traction cable, wherein the lower frame is slidably connected to the upper frame; and applying a predetermined pressure to move the lower frame relative to the upper frame, thereby increasing a traction force applied on the traction cable.

Description

[0001] This application claims the rights and priority of EP23382606.4, filed on June 16, 2023.

[0002] This disclosure relates to an overload testing system for testing the overload mechanism of a traction system of a lifting device. Furthermore, this disclosure relates to a method for testing the overload mechanism of a traction system of a lifting device and a method for setting a load threshold for the overload mechanism of the traction system of the lifting device. Background Technology

[0003] Lifting equipment or systems can be installed at structures for the vertical transport of goods or users. Service lifting equipment or systems are used to lift and lower technicians or maintenance personnel. These service lifts or elevators can be installed in, for example, wind turbines, construction sites, cranes, silos, chimneys, and various types of towers. Building maintenance units used for maintenance operations in high-rise buildings or structures are also examples of service lifting systems.

[0004] Hoists are typically used in the form of elevator-like structures, where a load-bearing structure for transporting people and / or equipment is raised and / or lowered within a building structure (e.g., within a wind turbine tower). For example, the load-bearing structure may be a lifting platform or a lifting cabin. Service lifting systems or service lifting equipment may include a load-bearing structure suspended by cables or ropes within a lifting channel or path. For example, in a building maintenance unit, the load-bearing structure may be a lifting cabin, a carrier, or a lifting platform.

[0005] Service lifts or service lifting equipment may include a traction system for raising and lowering a load-bearing structure. In some examples, the drive system may involve the use of a traction cable or traction chain. The traction system may be mounted or attached to the load-bearing structure. The traction system may include a housing containing a drive or traction mechanism, such as a motor that drives the traction or pulleys. The motor is typically an electric motor, although other motors may also be used in principle. The drive mechanism engages the traction cable or traction chain to raise and lower the load-bearing structure. Thus, the load-bearing structure may be supported by the traction cable or traction chain.

[0006] Using such service lifts may require compliance with standards and safety regulations. For example, some standards specify the rated load capacity of load-bearing structures, such as lift cabins or lift platforms. Load sensors or overload mechanisms can be used to prevent the use of load-bearing structures when excessive loads or overloads (i.e., loads exceeding load thresholds) are detected. Load thresholds can be defined for specific applications or specific types of load sensors or overload mechanisms.

[0007] In some examples, an overload mechanism may be installed within the traction system. The overload mechanism detects excessive load by sensing the degree of tension or traction force applied to the traction cable. Once an overload is detected, a warning signal is triggered to alert the load-bearing structure that the load exceeds the overload mechanism's load threshold. The load threshold is related to the rated load capacity of the lifting system. For example, the overload mechanism's load threshold is typically related to the rated load capacity or the rated load capacity multiplied by a safety factor.

[0008] However, these overload mechanisms may wear out or malfunction over time. Therefore, the load threshold of the overload mechanism may change over time. This could result in the warning signal not being triggered after reaching an excessive load. The load-bearing structure may not have been designed to withstand such excessive loads. Therefore, the overload mechanism must be inspected and adjusted regularly to ensure that the load-bearing structure does not bear excessive loads.

[0009] Overload mechanisms can be tested by placing multiple heavy objects within the load-bearing structure to stretch the traction cable. When the overload mechanism detects an excessive load, it outputs a warning signal. This indicates that the load on the load-bearing structure exceeds the overload mechanism's load threshold. However, this method means that workers must move multiple heavy objects (e.g., heavy blocks) into the lifting system. This can be complex in some lifting systems. For example, transporting heavy objects to some wind turbines, such as offshore wind turbines, can be time-consuming and labor-intensive. Furthermore, handling heavy objects may involve safety risks. Additionally, workers must test the overload mechanism inside the load-bearing structure, such as within the lifting pod or lifting load. This can involve high safety risks.

[0010] In other examples, the load-bearing structure can be pulled from below to simulate a load. However, this requires installing a pulling system beneath the load-bearing structure, which could pose a safety risk. Furthermore, installing a pulling system beneath the load-bearing structure can be time-consuming.

[0011] This disclosure provides examples of systems and methods that at least partially address some of the aforementioned drawbacks. Summary of the Invention

[0012] In a first aspect, an overload testing system is provided for testing the overload mechanism of a traction system for a lifting device. The lifting device may include a load-bearing structure, a traction cable, and a traction system disposed at the load-bearing structure for driving the load-bearing structure along a lifting path. The traction system may include a traction mechanism that engages the traction cable to raise and lower the load-bearing structure. The traction system may also include an overload mechanism for preventing movement of the load-bearing structure when the load on the load-bearing structure exceeds a load threshold. The overload mechanism can detect excessive loads, i.e., loads on the load-bearing structure exceeding the load threshold, by sensing or monitoring the traction force or degree of tension applied to the traction cable.

[0013] The terms "lifting equipment" and "lifting system" are used interchangeably in this document. Lifting equipment can be a service lifting system or a service lifting device. For example, a service lifting system can be a building maintenance unit and / or installed within a slender structure, such as within a wind turbine tower.

[0014] The load-bearing structure is configured to support and transport personnel and / or equipment along a lifting path. The load-bearing structure can be raised and / or lowered to transport personnel and / or equipment within the structure. Examples of load-bearing structures may be lifting cabins, lifting cages, or lifting platforms. Lifting cages and lifting platforms can be used in building maintenance units.

[0015] The overload testing system includes a lower frame and an upper frame, the upper frame being configured to connect to the traction cable of a lifting device. The upper frame is slidably connected to the lower frame. Both the lower and upper frames include channels for receiving the traction cable. The overload testing system also includes a pressure element disposed between the upper and lower frames for moving the lower frame relative to the upper frame. The lower frame is configured to be supported on the traction system of the lifting device.

[0016] When the upper frame is connected to the traction cable and the lower frame is supported by the traction system, the upward movement of the upper frame is prevented. Therefore, the relative movement between the upper and lower frames results in downward pressure towards the load-bearing structure, which increases the traction force on the traction cable. The degree of tension thus increases. This tension in the traction cable can therefore be sensed by the overload mechanism. The overload mechanism can detect excessive tension in the traction cable, indicating an excessive load. This can be used to test the functionality of the overload mechanism. For example, if the pressure applied by the pressure element exceeds the theoretical load threshold of the overload mechanism, and the traction force generated in the traction cable does not trigger the warning signal of the overload mechanism, this may indicate a malfunction in the overload mechanism.

[0017] In this respect, the overload testing mechanism is simplified, and the testing time is significantly reduced. Furthermore, the overload testing system can be installed at or on the load-bearing structure. Therefore, the overload testing system can be installed from the landing platform, avoiding installation operations below the load-bearing structure. Moreover, it avoids the handling and transportation of heavy objects, thus reducing safety risks. Additionally, the pressure provided by the pressure element can be precisely controlled. As a result, the tension of the traction cable can also be precisely controlled. Therefore, the accuracy of the overload testing mechanism is improved.

[0018] Furthermore, since the lower frame can be supported by a traction system, it can be supported on a robust structure such as a traction or lifting mechanism. Therefore, high stress can be applied to the load-bearing structure from the lower frame without damaging it.

[0019] In another aspect, a method is provided for testing an overload mechanism of a traction system for a lifting device. The lifting device can be based on the lifting device described in the foregoing aspect. The method includes positioning a lower frame of the overload testing system to support the traction system, and connecting an upper frame of the overload testing system to a traction cable. The lower frame is slidably connected to the upper frame. A predetermined pressure is then applied to move the lower frame relative to the upper frame, thereby increasing the traction force applied to the traction cable.

[0020] This method can employ any overload testing system according to any example herein. A predetermined pressure generates a predetermined load on the traction cable. This predetermined load can be a load greater than the expected rated load capacity, or a load greater than the expected rated load capacity multiplied by a safety factor. Therefore, if the overload mechanism detects excessive stretching of the traction cable before reaching the predetermined load, this may indicate that the overload mechanism is not properly calibrated. In this case, the load-bearing structure can still withstand a greater load, so the load threshold of the overload mechanism can be adjusted to increase its value.

[0021] The advantages derived from this aspect are similar to those mentioned regarding the first aspect.

[0022] In another aspect, a method is provided for setting a load threshold for an overload mechanism of a traction system of a lifting device. The lifting device can be configured according to the aforementioned aspects. The method includes testing the overload mechanism according to any example herein, and adjusting the overload mechanism to set a load threshold corresponding to a predetermined pressure applied to the overload test system.

[0023] Based on this, the load threshold of the overload mechanism can be precisely set. Therefore, the overload mechanism can be calibrated to ensure that a warning signal is output when the load exceeds a predetermined load (the load caused by a predetermined pressure). Thus, the overload mechanism can be precisely adjusted. This avoids the safety risks associated with using an incorrectly calibrated load-bearing structure. Attached Figure Description

[0024] Non-limiting examples of this disclosure will be described below with reference to the accompanying drawings, in which:

[0025] Figure 1 The illustration schematically depicts a lifting device according to an example of this disclosure;

[0026] Figure 2 This illustrates a traction system according to an example of this disclosure;

[0027] Figure 3 It indicates Figure 2 The traction mechanism of the traction system;

[0028] Figure 4A and 4BThese respectively illustrate the overload mechanism according to the example of this disclosure when the traction load is less than the load threshold and when the traction load is greater than the load threshold;

[0029] Figure 5 An overload test system mounted on a load-bearing structure according to an example of this disclosure is schematically illustrated;

[0030] Figure 6A and 6B These respectively represent overload test systems in the initial position and the extended position according to examples of this disclosure;

[0031] Figure 7A and 7B This is an isometric view of an overload testing system according to an example of this disclosure;

[0032] Figure 8 yes Figure 7A and 7B Cross-sectional view of the overload test system; and

[0033] Figure 9 A block diagram schematically illustrates a method for testing an overload mechanism of a traction system for lifting equipment, according to an example of this disclosure. Detailed Implementation

[0034] In these figures, the same reference numerals have been used to specify matching elements.

[0035] Figure 1 A lifting device is schematically illustrated, having a load-bearing structure that can move up and down along a lifting path. In this example, the load-bearing structure is a lifting cabin 100. In other examples, the load-bearing structure may be a lifting cage or a lifting platform.

[0036] The lifting device in this example is guided by a pair of tensioned cables 121 arranged along the lifting path to guide the movement of the load-bearing structure (lift cabin 100 in this example). The tensioned cables 121 are located on the side of the load-bearing structure. Therefore, the lifting device in this example is a cable-guided lifting system. In other examples, the upward and downward movement of the load-bearing structure can be guided by a structure, such as a ladder-structure guided lifting system.

[0037] The lifting device in this example is a service lifting system. Specifically, Figure 1 The lifting system described here is a service lifting system installed within a wind turbine tower. Therefore, a wind turbine tower may include the lifting system of this example. In other examples, the elevator system may be housed in other elongated structures or may be a building maintenance unit.

[0038] The lifting system of this figure includes a traction cable 110 that extends into the lifting cabin or lifting carrier 100 to pass through a traction system 140. In this example, the traction system 140 is located inside the lifting cabin 100. The traction system 140 can be mounted on a support structure of the load-bearing structure (e.g., the lifting cabin 100). An opening 102 formed in the upper wall 101 of the lifting cabin 100 allows the traction cable 110 to enter the lifting cabin 100.

[0039] In this figure, the lifting system or lifting device also includes a safety cable 120. The safety cable 120 passes through a fall arrestor 130 connected to the lift cabin 100. The fall arrestor 130 may include an overspeed detector and a blocking system for blocking the lift cabin 100 when the overspeed detector detects overspeed. In this example, the fall arrestor 130 engages the safety cable 120; however, in other examples, the fall arrestor may engage the traction cable 110 directly.

[0040] Figure 2 and Figure 3 They respectively represent Figure 1 The lifting system 140 includes a traction system and a traction mechanism. The traction system 140 includes a traction hoist or traction mechanism 150 disposed within a housing 151. The housing 151 surrounds the traction mechanism 150. A traction cable 110 enters the housing 151 through an inlet hole 152 located on the upper side 154 and exits through an outlet hole 153 located on the bottom side 155 of the housing 151. In this example, the traction cable 110 completely bypasses the traction pulley 160 and then exits the traction mechanism 150 through the outlet hole 153. In this example, a traction cable guide 161, a first pressure roller 162, and a second pressure roller 163 ensure that the traction cable 110 remains in contact with the traction pulley 160 along its entire periphery.

[0041] The traction system 140 in this example also includes an electric motor 141 that drives a traction pulley 160 via a gear system 142 involving one or more stages. Rotation of the traction pulley 160 causes the traction cable 110 to ascend or descend. Thus, a load-bearing structure, such as the lift cabin 100, can move upward or downward. The traction system 140 may also include an electromagnetic brake that engages rotating components of the traction system 140, such as the shaft of the motor 141, the gears or shafts of the gear system 142, or the traction pulley 160. When power is supplied to the electromagnetic brake, the electromagnetic brake is released, and the traction pulley 160 can rotate, resulting in vertical movement of the load-bearing structure. Conversely, when no power is supplied to the electromagnetic brake, a brake pad prevents rotation of the traction pulley 160, preventing vertical movement of the load-bearing structure.

[0042] The traction system 140 in this example also includes an overload mechanism 170. The overload mechanism 170 continuously measures the load supported by a load-bearing structure (e.g., elevator 100 or elevator platform). In this example, the overload mechanism 170 measures the degree of tension of the traction cable 110. Therefore, the traction force of the traction cable 110 is continuously monitored by the overload mechanism 170. The overload mechanism 170 in this example is disposed within the housing 151 of the traction mechanism 150. The overload mechanism 170 in this example is located between the inlet port 152 and the traction pulley 160.

[0043] Figure 4A and 4B These figures illustrate overload mechanisms according to examples of this disclosure when the traction load is less than a load threshold and when the traction load is greater than a load threshold. The overload mechanism 170 in these figures is disposed within the traction mechanism 150. In these figures, the overload mechanism 170 is disposed between the inlet orifice 152 of the traction mechanism and the traction cable guide 161 surrounding the traction pulley 160. The inlet orifice 152 of this example includes an inlet orifice bushing 156 that defines the orifice diameter of the inlet orifice 152. The overload mechanism 170 includes a pivotable bracket 171 and a pivotable roller 172 that rotates toward an overload switch 173 when the traction force of the traction cable 110 increases.

[0044] exist Figure 4A In this configuration, the traction force on the traction cable 110 is lower than the load threshold set by the overload mechanism 170. When the traction force on the traction cable 110 increases, the bracket 171 rotates towards the overload switch 173. Therefore, the tensile force on the traction cable 110 is continuously monitored by the overload mechanism 170. Figure 4B As shown, when the tensile or traction force reaches the load threshold defined by the overload mechanism 170, the bracket 171 contacts the overload switch 173, and the overload mechanism 170 can output a warning signal. In some examples, the movement of the load-bearing structure may also be blocked when the bracket 171 contacts the overload switch 173.

[0045] The position of the overload switch 173 can be changed by the extension of the spring 174, which can be adjusted by the screw 175. Using a suitable tool, the screw 175 can be rotated from outside the load-bearing structure, such as from outside the lifting chamber 100. By changing the extension of the spring 174, the load threshold defined by the overload mechanism 170 can be adjusted.

[0046] Figure 5An overload testing system mounted on a load-bearing structure according to an example of this disclosure is schematically illustrated. The overload testing system 10 is mounted on an elevator 100; however, in other examples, the overload testing system 10 may be mounted inside the elevator 100 or in other types of load-bearing structures. The elevator system of this example may be adapted to any example herein. A traction cable 110 passes through an opening 102 in the upper wall 101 of the elevator 100 to the traction system. Figure 5 (Not visible in the image). The traction system according to this example is located inside the elevator cabin 100.

[0047] The lifting system in this example also includes a safety cable 120 that passes through a fall arrestor 130 located within the lifting cabin 100.

[0048] The overload testing system 10 includes a lower frame 20 and an upper frame 30. The upper frame 30 is slidably connected to the lower frame 20. The lower frame 20 and the upper frame 30 include channels 21 and 31 to accommodate a traction cable 110. Thus, the traction cable 110 extends along the upper channel 31 and the lower channel 21.

[0049] The overload testing system 10 in this example also includes an upper bushing 50 and a lower bushing 40. The upper bushing 50 and the lower bushing 40 surround the traction cable 110 and are respectively disposed within the corresponding channels 31 and 21. Thus, the upper bushing 50 and the lower bushing 40 are configured to fit into the corresponding channels 21, 31 and accommodate the traction cable 110.

[0050] In this figure, the lower frame 20 is supported on the traction system 140. Therefore, the lower frame 20 is configured to be supported on or by the traction system 140. The lower frame 20 may be supported by the housing 151 of the traction mechanism 150, for example by the upper side 154 of the housing 151 of the traction mechanism 150. In some examples, the lower bushing 40 includes an engagement portion to engage the traction system 140, such as the inlet bushing 156 of the traction mechanism 150. Therefore, pressure from the lower frame 20 can be effectively transmitted to the elevator 100 in the event of damage to the elevator 100 via the traction system 140, such as the traction mechanism 150.

[0051] In this figure, the upper frame 30 is held by a cable clamp 60 disposed above the upper frame 30. In this example, the cable clamp 60 holds the traction cable 110. Therefore, the cable clamp 60 prevents upward movement of the upper frame 30. Thus, the upper frame is configured to engage with the traction cable 110. The upper bushing 50 may include an engaging portion to engage the cable clamp 60.

[0052] The overload testing system also includes a pressure element 70 disposed between the upper frame 30 and the lower frame 20 for moving the lower frame 20 relative to the upper frame 30. In this example, the pressure element 70 is configured to extend from an initial position to an extended position. Because the upward movement of the upper frame 30 is blocked by the cable clamp 60, the extension of the pressure element 70 causes the lower frame 20 to move downward, thereby pushing the elevator 100. The downward movement of the elevator 100 may be blocked by the electromagnetic brake of the traction mechanism 150. Therefore, the pressure applied by the pressure element 70 to the lower frame 20 and the upper frame 30 causes the traction cable 110 to stretch. This increase in the traction force of the traction cable 110 is monitored by the overload mechanism 170.

[0053] Figure 6A and 6B These respectively illustrate the overload test system in the initial position and the extended position according to the examples of this disclosure. Figure 6A In the initial position, the overload test system 10 is in the test position, where the pressure element 70 does not apply pressure to the upper frame 30 and the lower frame 20. Figure 6B In this configuration, pressure element 70 applies pressure to the upper frame 30 and the lower frame 20. This pressure causes the lower frame 20 to move relative to the upper frame 30 and the traction cable 110, which passes through holes in the upper frame 30 and the lower frame 20, to stretch.

[0054] In these figures, the lower bushing 40 surrounds the traction cable 110 and is disposed in a channel of the lower frame 20, while the upper bushing 50 also surrounds the traction cable 110 and is disposed in a channel of the upper frame 30. The lower bushing can be supported on the traction system, and the upper bushing is blocked by the cable clamp 60 clamped on the traction cable 110. Since the upward movement of the upper frame 30 is restricted by the cable clamp 60, the relative movement caused by the pressure element causes the lower frame 20 to move downward, and in turn causes the traction system and the load-bearing structure to move downward.

[0055] In this example, pressure element 70 includes a hydraulic cylinder. In other examples, other types of pressure elements, such as pneumatic or mechanical pressure elements, may be used instead. The hydraulic cylinder can extend from the lower end connected to the lower frame 20 to the upper end connected to the upper frame 30. The distance between the lower and upper ends may increase when a predetermined pressure is applied to the hydraulic cylinder. Therefore, the hydraulic cylinder can extend when the predetermined pressure is applied. Thus, the upper frame 30 can move relative to the lower frame 20.

[0056] In this example, the hydraulic cylinder is configured to connect to a hydraulic pressure source. Therefore, the pressure applied to the upper and lower frames can be controlled. This allows a predetermined pressure to be applied. The pressure source can provide a specific pressure. The pressure generated by the pressure source can be selected to create a predetermined load on the traction cable, i.e., a specific degree of tension on the traction cable 110. The predetermined load on the traction cable 110 generated by the predetermined pressure can be the rated load capacity multiplied by a safety factor.

[0057] In some examples, the pressure source can be a manual pump. The manual pump can be connected to the hydraulic cylinder via pipes. The manual pump can supply a specific pressure to the pressure element. When the manual pump is activated, oil is released from the manual pump to the pressure element.

[0058] In these figures, a first connecting assembly 80 is connected to the upper frame 30 and slides through a groove 25 disposed at the lower frame 20. The first connecting assembly 80 in these figures includes an upper roller 81 and a lower roller 82. The upper roller 81 and the lower roller 82 are rotatably connected to the upper roller and can move upward and downward along the vertical groove 25. Therefore, the relative movement between the upper frame 30 and the lower frame 20 is limited by the groove 25.

[0059] Although not shown in these figures, the overload testing system may include a second connection component that is connected to the other side of the upper frame 30 and slides through a slot provided on the other side of the lower frame 20.

[0060] Figure 7A and 7B This is an isometric view of an overload testing system according to an example of this disclosure. Figure 8 yes Figure 7A and 7B Cross-sectional view of the overload test system.

[0061] The overload testing system 10 in this example includes a cable clamp 60 for holding a traction cable (not shown in these figures). The cable clamp 60 is positioned above the upper frame 30 to limit upward movement of the upper frame relative to the lower frame 20. The cable clamp 60 includes a first clamping portion 61 and a second clamping portion 62 to surround the traction cable. The first clamping portion 61 can be connected to the second clamping portion 62 using connectors to hold the traction cable. In this example, a plurality of connectors 63 connect the first clamping portion 61 and the second clamping portion 62 to press the first clamping portion 61 and the second clamping portion 62 against each other, thereby clamping the traction cable between the first clamping portion 61 and the second clamping portion 62. Therefore, the cable clamp 60 can be mounted at any desired location of the traction cable. The connectors may include screws and nuts that tighten with a specific pressure to ensure a secure connection of the cable clamp 60 relative to the traction cable.

[0062] In these figures, the upper bushing 50 is positioned below the cable clamp 60 to connect the upper frame 30 to the traction cable in a fixed position. In these figures, the upper bushing 50 includes a first bushing portion and a second bushing portion to surround the traction cable. The bushing portions can be assembled together to enclose the traction cable. For example, an annular pressure element can be placed to surround and press the bushing portions. This configuration allows the upper bushing 50 to be installed on existing traction cables.

[0063] The upper bushing 50 in these figures includes an insertion portion 51 configured to insert into a channel 31 of the upper frame 30. The outer diameter of the insertion portion 51 is smaller than the diameter of the channel 31. Therefore, the insertion portion 51 can fit into the channel 31 of the upper frame 30. The upper bushing in this example also includes a stop portion 52 to prevent the upper bushing from being fully inserted into the channel 31. The outer diameter of the stop portion 52 in these figures is smaller than the diameter of the channel 31 to prevent the stop portion 52 from being inserted into the channel 31.

[0064] Furthermore, the upper bushing 50 of this example includes an engagement portion 53 to engage the cable clamp 60. The uppermost region of the engagement portion 53 can be received within a channel defined by the cable clamp 60. A stop portion 52 is disposed between the engagement portion 53 and the insertion portion 51.

[0065] In this example, the upper bushing 50 engages with the cable clamp 60, which allows the upper frame 30 of the overload test system 10 to be securely connected to the traction cable.

[0066] Similar to the upper bushing 50, the lower bushing 40 in these figures includes a first bushing portion and a second bushing portion to enclose the traction cable. The lower bushing 40 in this example includes an insertion portion 41, a stop portion 42, and an engagement portion 43. The insertion portion 41 is configured to fit into a channel 21 of the lower frame 20. The outer diameter of the insertion portion 41 is smaller than the inner diameter of the channel 21 of the lower frame so as to be inserted into the channel 21. The outer diameter of the stop portion 42 is larger than the inner diameter of the channel 21 to prevent the stop portion 42 from being inserted into the channel 21. The engagement portion 43 can engage a traction system, for example, it can fit into an inlet port of a traction mechanism.

[0067] The lower frame 20 of this example includes a base 22 having a channel 21. The lower frame 20 also includes a first sidewall 23 and a second sidewall 24. The sidewalls 23 and 24 extend vertically from the base 22. Therefore, the lower frame 20 may include a generally U-shaped profile. The sidewalls 23 and 24 may be welded to the base 22. The sidewalls 23 and 24 in these figures include vertical grooves 25 for guiding upward and downward movement of the upper frame 30 relative to the lower frame 20.

[0068] In this example, the upper frame 30 includes a base 32 with a channel 31 and two sidewalls 33, 34 extending vertically from the base 32. Therefore, the upper frame 30 has a generally U-shaped profile. The base 32 is supported by the flat portions of the sidewalls 23, 24 of the lower frame 20. The first sidewall 33 and the second sidewall 34 of the upper frame 30 extend toward the base 22 of the lower frame 20.

[0069] In this example, the side walls 33 and 34 of the upper frame 30 are disposed between the side walls 23 and 24 of the lower frame 20. Therefore, the upper frame 30 can substantially engage with the lower frame 20. In other examples, the side walls 23 and 24 of the lower frame 20 may be disposed between the side walls 33 and 34 of the upper frame 30. In this example, the pressure element 70 is disposed between the side walls 33 and 34 of the upper frame 30 and between the side walls 23 and 24 of the lower frame 20.

[0070] In this example, the pressure element 70 is a hydraulic cylinder. The hydraulic cylinder includes an upper end connected to a base 32 of the upper frame 30 and a lower end connected to a base 22 of the lower frame 20. Therefore, the extension and compression of the pressure element 70 causes the lower frame 20 to move relative to the upper frame 30.

[0071] In this example, the overload testing system 10 includes a first connecting assembly 80 slidably connecting the first sidewalls 23 and 33 and a second connecting assembly 85 slidably connecting the second sidewalls 24 and 34. The first connecting assembly 80 is rotatably connected to the first sidewall 33 of the upper frame 30 and slidably connected to the first sidewall 23 of the lower frame 20 via a slot 25. The second connecting assembly 85 is rotatably connected to the second sidewall 34 of the upper frame 30 and slidably connected to the second sidewall 24 of the lower frame 20 via a slot 25 in the second sidewall 24.

[0072] The connecting components 80 and 85 in these figures include an upper roller and a lower roller. The rollers are rotatably connected to the side walls 33 and 34 of the upper frame 30. These rollers can move through the grooves in the side walls 23 and 24 of the lower frame 20.

[0073] Figure 9 A block diagram schematically illustrates a method for testing an overload mechanism of a traction system for a lifting system, according to an example of this disclosure. The overload mechanism 170, traction system 140, and lifting system can be based on any example herein. Method 500 can be employed using an overload test system 10 according to any example herein.

[0074] Method 500 includes positioning the lower frame 20 of the overload test system 10 for support on the traction system 140, as shown in box 510. The lower frame 20 may be disposed on the inlet port 152 of the traction mechanism 150 of the traction system 140.

[0075] In some examples, positioning the lower frame 20 for support on the traction system 140 may include placing a lower bushing 40 for support on the traction system and inserting the traction cable 110 into the lower bushing 40. The lower bushing 40 may accommodate the traction cable 110 by placing a first bushing portion and a second bushing portion around the traction cable 110. These bushing portions may then be joined together to surround the traction cable 110.

[0076] The engaging portion 43 of the lower bushing 40 can be supported on the inlet bushing 156 of the traction mechanism 150. The engaging portion 43 can be inserted into the inlet bushing 156. The bushing portion can be positioned around the traction cable 110 and can then slide along the traction cable to engage the traction mechanism, such as the inlet hole 152 or the inlet bushing 156. Then, a portion of the lower bushing 40, such as the insertion portion 41, can be inserted into the channel 21 of the lower frame 20. Insertion can be prevented by a stop portion 42 that can contact the lower surface of the base 22 of the lower frame 20. Thus, the channel 21 can accommodate the traction cable 110 and the insertion portion 41 of the lower bushing 40.

[0077] Method 500 also includes connecting the upper frame 30 of the overload test system 10 to the traction cable 110, as shown in box 520. The lower frame 20 is slidably connected to the upper frame 30. The upper frame 30 and the lower frame 20 can be adapted to any example herein.

[0078] When the lower frame 20 is supported on the traction system 140, the upper frame 30 can be connected to the traction cable 110. In some examples, connecting the upper frame 30 to the traction cable 110 includes placing an upper bushing 50 over the upper frame 30 and inserting the traction cable into the upper bushing 50. Inserting the traction cable into the upper bushing may include placing a first bushing portion and a second bushing portion around the traction cable 110. Thus, the bushing portions can surround the traction cable 110.

[0079] Connecting the upper frame 30 to the traction cable 110 may include inserting the upper bushing 50 into the channel 31 of the upper frame 30. The upper bushing 50 surrounding the traction cable 110 can slide along the traction cable into the channel 31. The insertion portion 51 of the upper bushing 50 can be inserted into the channel 31. Insertion of the upper bushing 50 can be prevented by the stop portion 52 of the upper bushing 50. Thus, the upper bushing 50 surrounding the traction cable 110 is accommodated in the channel 31.

[0080] In some examples, connecting the upper frame 30 to the traction cable 110 includes placing a cable clamp 60 for support on the upper bushing 50. Thus, the cable clamp 60 can hold the traction cable 110 to prevent upward movement of the upper frame 30. Therefore, the upper frame 30 can be securely connected to the traction cable 110. In some examples, clamping the cable clamp 60 onto the traction cable 110 may include connecting a first clamping portion 61 to a second clamping portion 62 to press the traction cable 110 therebetween. When the lower bushing 40 is positioned on the channel 21 and supported on the traction system 140, the cable clamp 60 can be placed to support the upper bushing 50 disposed within the channel 31.

[0081] As shown in box 530, method 500 further includes applying a predetermined pressure to move the lower frame 20 relative to the upper frame 30, thereby increasing the traction force applied to the traction cable 110. The predetermined pressure is selected to generate a predetermined load on the traction cable 110. This predetermined load can be the rated load capacity, or the rated load capacity multiplied by a safety factor. The predetermined load is the load that should theoretically trigger the overload mechanism, or in other words, the predetermined load should theoretically correspond to the load threshold set by the overload mechanism. In an elevator installed in a wind turbine, this predetermined load can be the rated load capacity of the lifting system multiplied by a safety factor corresponding to 1.25.

[0082] In some examples, when the pressure element is a hydraulic cylinder, the method may also include connecting the hydraulic cylinder to a hydraulic pressure source. The hydraulic pressure source may be a manual pump. The hydraulic pressure can then be activated, for example, by an operator releasing oil through the manual pump to provide a predetermined pressure to the hydraulic cylinder. The manual pump can be connected to the hydraulic cylinder and can provide dynamic pressure to the pressure element. Therefore, the traction load applied to the traction cable can be gradually increased. This allows for precise increases in the traction cable load. Therefore, the overload mechanism can be accurately tested.

[0083] The methods used to test the overload mechanism can also be used to calibrate it. For example, when the threshold load is greater than a predetermined load, the threshold load of the overload mechanism can be reduced. Conversely, when the predetermined load is greater than the threshold load, the threshold load can be increased.

[0084] A method for setting a load threshold for an overload mechanism is provided. The overload mechanism 170, traction system 140, and lifting system can be based on any example herein. The method for setting the load threshold includes testing the overload mechanism 170 according to any example herein; and adjusting the overload mechanism 170 to set a load threshold corresponding to a predetermined pressure applied to the overload test system.

[0085] A predetermined pressure can be selected to generate a predetermined load on the traction cable 110. The predetermined load can be the maximum lifting capacity or the maximum lifting capacity multiplied by a safety factor. Therefore, the predetermined load is the theoretical load threshold of the overload mechanism. However, as mentioned earlier, the load threshold may deviate over time.

[0086] Pressure element 70 can apply progressively increasing pressure to the upper frame 30 and lower frame 20. This increase in pressure leads to an increase in the traction force on the traction cable 110, which is continuously monitored by overload mechanism 170. When the traction force on the traction cable 110 exceeds the load threshold of overload mechanism 170, overload mechanism 170 triggers a warning signal.

[0087] In some examples, the overload mechanism 170 triggers a warning signal before reaching a predetermined load. Therefore, the load threshold is below the predetermined load. Therefore, the load threshold of the overload mechanism 170 can be adjusted. Therefore, the load threshold can be increased. The overload mechanism can be adjusted to increase the load threshold until the overload mechanism 170 outputs a warning signal when a predetermined pressure is applied.

[0088] When the load threshold is lower than the predetermined load caused by the predetermined pressure, the method of setting the load threshold of the overload mechanism 170 may include increasing the load threshold until the overload mechanism 170 outputs a warning signal when the predetermined pressure is applied.

[0089] In some examples, the overload mechanism 170 may not trigger a warning signal when a predetermined load is applied. Therefore, the load threshold is greater than the predetermined load. Thus, the overload mechanism 170 can be adjusted to lower the load threshold. When the load threshold is greater than the predetermined load caused by a predetermined pressure, the method for setting the load threshold of the overload mechanism 170 may include lowering the load threshold until the overload mechanism 170 does not output a warning signal when the predetermined pressure is applied.

[0090] The overload mechanism can be adjusted from outside the load-bearing structure, such as from outside the elevator compartment. A tool can be used to rotate screw 175 to change the extension of spring 174. Therefore, the position of the overload switch can be adjusted. Correspondingly, the load threshold can be adjusted.

[0091] For completeness, various aspects of this disclosure are set out in the following numbered clauses:

[0092] Clause 1: An overload testing system for testing the overload mechanism of a traction system of a lifting device, the overload testing system comprising:

[0093] Lower frame;

[0094] The upper frame is configured to be connected to the traction cable of the lifting equipment, wherein the upper frame is slidably connected to the lower frame;

[0095] A pressure element, which is disposed between the upper frame and the lower frame, is used to move the lower frame relative to the upper frame;

[0096] The lower and upper frames include channels for accommodating the traction cables.

[0097] Clause 2: The overload testing system according to Clause 1 further includes a cable clamp for holding the traction cable above the upper frame to prevent the upper frame from moving upward, wherein the cable clamp includes:

[0098] First clamping part;

[0099] The second clamping part, and

[0100] A connector for pressing a first clamping portion and a second clamping portion together to clamp a traction cable between the first clamping portion and the second clamping portion.

[0101] Clause 3: An overload test system according to any one of Clauses 1-2, wherein the pressure element is configured to extend from the initial position to the extended position.

[0102] Clause 4: An overload test system according to any one of Clauses 1-3, wherein the pressure element includes a hydraulic cylinder.

[0103] Clause 5: The overload test system as described in Clause 4, wherein the hydraulic cylinder extends from the lower end connected to the lower frame to the upper end connected to the upper frame.

[0104] Clause 6: The overload test system according to Clause 5, wherein the distance between the lower and upper ends increases when a predetermined pressure is applied to the hydraulic cylinder.

[0105] Clause 7: An overload test system according to any one of Clauses 4-6, wherein the pressure element is configured to be connected to a hydraulic pressure source.

[0106] Clause 8: The overload test system according to any one of Clauses 1-7 further includes:

[0107] Upper bushing, configured to fit the upper frame channel and accommodate the traction cable; and / or

[0108] The lower bushing is configured to fit the channel of the lower frame and accommodate the traction cable.

[0109] Clause 9: The overload test system as described in Clause 8, wherein the upper bushing and / or lower bushing includes a first bushing portion and a second bushing portion to surround the traction cable.

[0110] Clause 10: The overload test system according to any one of Clauses 8-9, wherein the upper bushing comprises:

[0111] The insertion portion has an outer diameter smaller than the diameter of the channel in the upper frame, such that the insertion portion is configured to insert into the channel; and

[0112] The stop portion has an outer diameter larger than the diameter of the channel in the upper frame, so as to prevent the stop portion from being inserted into the channel.

[0113] Clause 11: An overload testing system according to any one of Clauses 8-10, wherein the upper bushing includes an engagement portion for engaging cable clamps.

[0114] Clause 12: The overload test system according to any one of Clauses 8-11, wherein the lower bushing comprises:

[0115] The insertion portion has an outer diameter smaller than the diameter of the channel in the lower frame, such that the insertion portion is configured to insert into the channel; and

[0116] The stop portion has an outer diameter larger than the diameter of the channel in the lower frame, so as to prevent the stop portion from being inserted into the channel.

[0117] Clause 13: An overload test system according to any one of Clauses 8-12, wherein the lower bushing includes an engagement portion for engaging the traction system.

[0118] Clause 14: An overload test system according to any one of Clauses 1-13, wherein the following frame comprises:

[0119] Including the base of the channel;

[0120] The first sidewall extending vertically from the base; and

[0121] The second sidewall extends vertically from the base.

[0122] Clause 15: The overload test system as described in Clause 14, wherein the upper frame comprises:

[0123] Including the base of the channel;

[0124] The first sidewall extending vertically from the base; and

[0125] The second sidewall extends vertically from the base;

[0126] The first and second sidewalls extend toward the base of the lower frame.

[0127] Clause 16: The overload testing system according to Clause 15, wherein the pressure element is disposed between the side wall of the upper frame and the side wall of the lower frame.

[0128] Clause 17: An overload testing system according to any one of Clauses 15-16, wherein the sidewalls of the upper frame are disposed between the sidewalls of the lower frame.

[0129] Clause 18: An overload testing system according to any one of Clauses 15-17, wherein the sidewalls of the lower frame include slots.

[0130] Clause 19: The overload testing system pursuant to Clause 18 further includes:

[0131] A first connecting assembly, rotatably connected to a first wall of the upper frame and slidably connected to a first wall of the lower frame via a slot; and

[0132] The second connecting component is rotatably connected to the second sidewall of the upper frame and slidably connected to the second sidewall of the lower frame via a slot.

[0133] Clause 20: A method for testing the overload mechanism of a traction system for a lifting device, wherein the lifting device comprises:

[0134] Load-bearing structure;

[0135] traction cables; and

[0136] A traction system installed at the load-bearing structure is used to drive the load-bearing structure along a lifting path by engaging a traction cable, wherein the traction system includes an overload mechanism for preventing movement of the load-bearing structure when the load on the load-bearing structure exceeds a load threshold.

[0137] The method includes:

[0138] The lower frame of the overload test system is positioned to support the traction system.

[0139] The upper frame of the overload testing system is connected to the traction cable, wherein the lower frame is slidably connected to the upper frame; and

[0140] A predetermined pressure is applied to move the lower frame relative to the upper frame, thereby increasing the traction force applied to the traction cable.

[0141] Clause 21: The method according to Clause 20, wherein positioning the lower frame for support on the traction system includes placing a lower bushing for support on the traction system and inserting the traction cable into the lower bushing.

[0142] Clause 22: The method according to Clause 21, wherein inserting the traction cable into the lower bushing includes placing the first bushing portion and the second bushing portion around the traction cable.

[0143] Clause 23: The method according to any one of Clauses 21-22, wherein positioning the lower frame for support on the traction system includes inserting the lower bushing into a channel in the lower frame.

[0144] Clause 24: The method according to any one of Clauses 20-23, wherein connecting the upper frame to the traction cable includes placing the upper bushing above the upper frame and inserting the traction cable into the upper bushing.

[0145] Clause 25: The method according to Clause 24, wherein inserting the traction cable into the upper bushing includes placing the first bushing portion and the second bushing portion around the traction cable.

[0146] Clause 26: The method according to any one of Clauses 24-25, wherein connecting the upper frame to the traction cable includes inserting the upper bushing into a channel in the upper frame.

[0147] Clause 27: The method according to any one of Clauses 24-26, wherein connecting the upper frame to the traction cable includes placing a cable clamp on the upper bushing and clamping the traction cable with the cable clamp to prevent upward movement of the upper frame.

[0148] Clause 28: The method according to any one of Clauses 20-27, wherein the pressure element is a hydraulic cylinder, and wherein the method includes connecting the hydraulic cylinder to a hydraulic pressure source.

[0149] Clause 29: The method according to Clause 28, wherein applying the predetermined pressure includes activating a hydraulic pressure source to provide the predetermined pressure to the hydraulic cylinder.

[0150] Clause 30: A method for setting a load threshold for an overload mechanism of a lifting device, wherein the lifting device comprises:

[0151] Load-bearing structure;

[0152] traction cables; and

[0153] A traction system installed at the load-bearing structure is used to drive the load-bearing structure along a lifting path by engaging a traction cable, wherein the traction system includes an overload mechanism for preventing movement of the load-bearing structure when the load on the load-bearing structure exceeds a load threshold.

[0154] The method includes:

[0155] Test the overload mechanism according to any of clauses 20-29;

[0156] Adjust the overload mechanism to set a load threshold corresponding to a predetermined pressure applied to the overload test system.

[0157] Although only a limited number of examples are disclosed herein, other alternatives, modifications, uses, and / or equivalents are possible. Furthermore, all possible combinations of the described examples are covered. Therefore, the scope of this disclosure should not be limited to the specific examples, but should only be determined by a fair interpretation of the appended claims.

Claims

1. An overload testing system for testing the overload mechanism of a traction system of a lifting device, the overload testing system comprising: Lower frame; An upper frame is configured to be connected to the traction cable of the lifting device, wherein the upper frame is slidably connected to the lower frame; A pressure element is disposed between the upper frame and the lower frame for moving the lower frame relative to the upper frame; The lower frame and the upper frame include channels for accommodating the traction cable.

2. The overload testing system according to claim 1, further comprising a cable clamp for clamping the traction cable above the upper frame to prevent the upper frame from moving upward, wherein the cable clamp comprises: First clamping part; The second clamping part, and A connector for pressing the first clamping portion and the second clamping portion together to clamp the traction cable between the first clamping portion and the second clamping portion.

3. The overload testing system according to any one of claims 1-2, wherein the pressure element is configured to extend from an initial position to an extended position.

4. The overload testing system according to any one of claims 1-3, wherein the pressure element comprises a hydraulic cylinder.

5. The overload testing system according to any one of claims 1-4, further comprising: The upper bushing is configured to fit the channel of the upper frame and accommodate the traction cable; and / or The lower bushing is configured to fit the channel of the lower frame and accommodate the traction cable.

6. The overload testing system of claim 5, wherein the upper bushing and / or the lower bushing comprises a first bushing portion and a second bushing portion to surround the traction cable.

7. A method for testing the overload mechanism of a traction system of a lifting device, wherein the lifting device comprises: Load-bearing structure; Traction cable; and A traction system installed at the load-bearing structure is used to drive the load-bearing structure along the lifting path by engaging a traction cable, wherein the traction system includes an overload mechanism for preventing movement of the load-bearing structure when the load on the load-bearing structure exceeds a load threshold. The method includes: The lower frame of the overload test system is positioned to be supported on the traction system; The upper frame of the overload testing system is connected to the traction cable, wherein the lower frame is slidably connected to the upper frame; and A predetermined pressure is applied to move the lower frame relative to the upper frame, thereby increasing the traction force applied to the traction cable.

8. The method of claim 7, wherein positioning the lower frame to support the traction system comprises placing the lower bushing to support the traction system and inserting the traction cable into the lower bushing.

9. The method of claim 8, wherein inserting the traction cable into the lower bushing comprises placing a first bushing portion and a second bushing portion around the traction cable.

10. The method according to any one of claims 8-9, wherein positioning the lower frame for support on the traction system includes inserting the lower bushing into a channel in the lower frame.

11. The method according to any one of claims 7-10, wherein connecting the upper frame to the traction cable comprises placing an upper bushing above the upper frame and inserting the traction cable into the upper bushing.

12. The method of claim 11, wherein inserting the traction cable into the upper bushing comprises placing a first bushing portion and a second bushing portion around the traction cable.

13. The method according to any one of claims 11-12, wherein connecting the upper frame to the traction cable includes inserting the upper bushing into a channel in the upper frame.

14. The method of claim 13, wherein connecting the upper frame to the traction cable includes placing a cable clamp on the upper bushing and clamping the traction cable with the cable clamp to prevent upward movement of the upper frame.

15. A method for setting a load threshold for an overload mechanism of a lifting device, wherein the lifting device comprises: Load-bearing structure; Traction cable; and A traction system disposed at the load-bearing structure is used to drive the load-bearing structure along a lifting path by engaging the traction cable, wherein the traction system includes an overload mechanism for preventing movement of the load-bearing structure when the load on the load-bearing structure exceeds a load threshold. The method includes: The overload mechanism is tested, wherein the test steps are performed according to any one of claims 7-14; Adjust the overload mechanism to set a load threshold corresponding to a predetermined pressure applied to the overload test system.

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