Large load test device and test method for crane

Abstract

The invention provides a large-scale load test device and test method for a crane, and relates to the technical field of nuclear power hoisting equipment, and the device comprises a cross beam, a shoulder beam, a supporting leg group, a pedestal, a pressure test assembly, a cushion block, and a tested piece. The supporting leg group is connected with the base and the shoulder beam to form a supporting frame; the pressure testing assembly is arranged on the upper plane of the shoulder beam. The cushion blocks are placed on the shoulder beam and located on the two sides of the hydraulic cylinder. And the cross beam is arranged above the shoulder beam and is positioned through a guide structure. During testing, the cross beam is jacked through the pressure testing assembly, and a load is applied to a tested piece connected between the cross beam and the base. According to the invention, hydraulic loading is used for replacing the traditional mode of'lifting equipment + balancing weight ', the device has the advantages of simple structure, simplified process flow, high load applying precision, safe and reliable operation and the like, and the problems of large occupied area, long period and high cost of the traditional test method are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant lifting equipment technology, and more particularly to a large load testing device and method for cranes. Background Technology

[0002] In recent years, with the accelerated approval process for nuclear power plants in my country, the market demand for cranes used in nuclear power plants has increased significantly. Crane operation is a high-risk operation. To ensure safety, load tests must be conducted on newly installed, modified, or overhauled cranes, including independent tests on key components such as hooks and beams, to check for deformation or cracks and verify whether their strength and rigidity meet the usage requirements.

[0003] Currently, existing component testing typically employs a "lifting equipment + counterweight" method, where the upper part of the component to be tested is connected to the lifting equipment, and the lower part is connected to a special tooling on which a counterweight of appropriate weight is applied. However, this existing technology has significant drawbacks: First, the process is complex, requires sophisticated tools, and the failure of the sling connection method can easily lead to accidents and injuries, resulting in high operational safety risks; second, large-tonnage tests require a large number of counterweights, occupying a large area, taking a long time, and requiring a large number of personnel, leading to high overall testing costs; finally, the mass matching accuracy of the test load is low, and the process of readjusting the counterweights during variable load tests is cumbersome and time-consuming.

[0004] Therefore, in order to solve the problems of complex process flow, long test cycle, large personnel input and low load accuracy, it is urgent to develop a new type of large load test device for cranes. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a large-load testing device and method for cranes. The invention uses a frame constructed from a base, legs, and shoulder beams, and employs a hydraulic assembly to lift the crossbeam, applying a tensile test load to the connected test specimen.

[0006] To achieve the above objectives, the present invention provides a large load testing device for cranes, comprising: a crossbeam, a shoulder beam, a leg assembly, a base, a pressure testing assembly, a pad, and a test piece; The base is located at the bottom, the lower end of the support leg assembly is connected to the base, and the upper end is connected to the shoulder beam to form a support frame; the pressure testing assembly is located above the shoulder beam to provide the loading force required for the test; the pad is placed on the shoulder beam and located on both sides of the hydraulic cylinder of the pressure testing assembly, and the height of the pad is greater than the free height of the hydraulic cylinder; the crossbeam is located above the shoulder beam and is positioned in cooperation with the shoulder beam through a guide structure; the crossbeam is used to connect the upper part of the test piece, the base is used to connect the lower part of the test piece, and the pressure testing assembly lifts the crossbeam to apply a load to the test piece.

[0007] Furthermore, the crossbeam is a welded structural component with the first structural beam as the main load-bearing component, and a single lifting point assembly is welded to its lower part near the middle position. The single lifting point assembly is used to connect the test specimen. Two pins are respectively provided at both ends of the crossbeam, and a lifting ring is provided at the top of the pin. The shoulder beam is a welded structural component with the second structural beam as the main load-bearing component, and two guide seats are respectively welded to its two ends. The guide seats are circular tube structures.

[0008] Furthermore, four sets of positioning blocks with an arc-shaped surface structure are welded to the upper middle of the shoulder beam. The pressure testing component includes a hydraulic cylinder, which is placed inside the positioning block. Two sets of first connecting seats are welded to the lower ends of the shoulder beam, and the first connecting seats are detachably connected to the outrigger assembly by fasteners.

[0009] Furthermore, the support leg assembly is a box-shaped welded structure, which is composed of multiple layers of support legs of different heights connected together. Each layer has four support legs of the same height as a group, and the combination of multiple layers of support legs can achieve different height adjustments. Flange plates are welded to the upper and lower planes of the support legs respectively, and the multiple layers of support legs, as well as the shoulder beam and the base, are connected by fasteners.

[0010] Furthermore, the base is a welded structural component with the third structural beam as the main load-bearing component, and its top view shows an I-beam-like structure. Four sets of second connecting seats are welded to the top of each end of the base, and the second connecting seats are detachably connected to the outrigger assembly through fasteners. A multi-lifting point group is welded in the middle of the base. The multi-lifting point group includes a lifting point located in the middle and aligned with the direction of the single lifting point assembly, and multiple lifting points on both sides perpendicular to the direction of the single lifting point assembly. By adjusting the combination of the "multi-lifting point group + single lifting point + outrigger assembly", the diverse load testing requirements of crane components can be flexibly met.

[0011] Furthermore, the pressure testing assembly includes a hydraulic cylinder, an oil pump, a pressure gauge, pipelines, and a control and display module; the hydraulic cylinder has a built-in pressure sensor for detecting the oil pressure inside the cylinder and feeding it back to the control and display module.

[0012] The present invention also provides a test method for a large load testing device for cranes, comprising the following steps: S1. Adjust the number of the support leg assembly to meet the height requirements of the test, and use fasteners to install and fix the support leg assembly, base and shoulder beam respectively; S2. Place the hydraulic cylinders of the pressure testing assembly in the positioning block area of ​​the shoulder beam, and place the pads on both sides of the hydraulic cylinders. The height of the pads is 10-15mm greater than the free height of the hydraulic cylinders. S3. Connect the pipelines to the pressure testing component to form a closed-loop system and debug and run it; S4. Check the values ​​of the pressure gauge and control display module to determine if there are any abnormalities. If there are any problems, return to S3 to readjust the system pipeline connections. If there are no problems, you can continue. S5. Connect the upper part of the test piece to the crossbeam; S6. Hoist the crossbeam and the test piece onto the shoulder beam, so that the pin of the crossbeam is aligned and inserted into the guide seat of the shoulder beam; S7. Connect the lower part of the test piece to the corresponding lifting point of the base; S8. Check the connection between the entire test piece and the mechanism to determine if there is any eccentricity or jamming. If there is a problem, return to S5 to readjust. If there is no problem, you can continue. S9. Press the start button to gradually increase the pressure through the pressure testing component until it reaches 0.5 times the test load, and observe the condition of the test piece; S10. Check if there is any abnormality in the test piece. If there is an abnormality, the test should be stopped. If there is no problem, continue loading until the test load is reached. S11. After the test is completed, the test piece is removed in reverse, and relevant inspections are carried out. The components of this test device are then collected, organized, and stored.

[0013] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: 1. The present invention provides a large load testing device and testing method for cranes, which replaces the traditional lifting equipment + counterweight method with hydraulic loading. It eliminates the need to prepare a large number of counterweights and use large-tonnage lifting equipment, effectively solving the problems of large work area, long preparation period and large personnel input of traditional testing methods, significantly reducing the overall testing cost and shortening the production cycle.

[0014] 2. The present invention provides a large load testing device and method for cranes, which uses a pressure testing component to provide power and the applied load changes linearly, resulting in higher mass matching accuracy compared to the traditional counterweight method. At the same time, the device has a built-in pressure sensor and is equipped with a display module, which has real-time dynamic display function and gradually increases the test load, avoiding the failure risk of directly suspending the test load and lifting slings in the traditional test method, making the operation simpler, faster and safer.

[0015] 3. The present invention provides a large load testing device and method for cranes. This design has a maximum test load capacity of up to 800 tons, and the test load error is within ±0.5%, which meets the requirements of the national standard GB / T 5905.1-2023 "Inspection and Testing Specifications for Cranes Part 1: General Rules": the test load error of the crane shall not exceed ±1%. Combined with the adjustable height design of the outrigger assembly and the multi-lifting point assembly design of the base, by adjusting the combination of "multi-lifting point assembly + single lifting point + outrigger assembly", it can flexibly meet the load testing requirements of crane components of different specifications and types. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the main structure of a large load testing device for cranes according to the present invention; Figure 2 This is a schematic diagram of the left-side structure of a large load testing device for cranes according to the present invention; Figure 3 This is a schematic diagram of the crossbeam structure in a large load testing device for cranes according to the present invention; Figure 4 This is a left-side view of the crossbeam structure in a large load testing device for cranes according to the present invention; Figure 5 This is a schematic diagram of the shoulder beam structure in a large load testing device for cranes according to the present invention; Figure 6 This is a left-side view of the shoulder beam structure in a large load testing device for cranes according to the present invention; Figure 7 This invention relates to a large load testing device for cranes. Figure 5 A schematic diagram of direction A; Figure 8 This is a schematic diagram of the outrigger assembly structure in a large load testing device for cranes according to the present invention; Figure 9 This is a top view of the outrigger assembly in a large load testing device for cranes according to the present invention. Figure 10 This is a schematic diagram of the base structure in a large load testing device for cranes according to the present invention; Figure 11 This is a top view of the base structure of a large load testing device for cranes according to the present invention; Figure 12 This is a schematic diagram of the pressure testing component in a large load testing device for cranes according to the present invention; Figure 13 This is a schematic diagram illustrating the operating conditions of a large load testing device for cranes as described in this invention. Figure 14 This is a schematic diagram of the second operating condition of the large load testing device for cranes described in this invention; Figure 15 This is a schematic diagram of the three operating conditions of a large load testing device for cranes according to the present invention; Figure 16 This is a flowchart of a test method for a large load testing device for cranes according to the present invention.

[0018] In the diagram: 1. Crossbeam; 2. Shoulder beam; 3. Outrigger assembly; 4. Base; 5. Pressure testing assembly; 6. Pad block; 7. Test specimen; 101. Lifting ring; 102. Pin shaft; 103. First structural beam; 104. Single lifting point assembly; 201. Second structural beam; 202. First connecting seat; 203. Guide seat; 204. Positioning block; 401. Second connecting seat; 402. Third structural beam; 403. Multi-lifting point assembly; 501. Hydraulic cylinder; 502. Oil pump; 503. Pressure gauge; 504. Pipeline; 505. Control and display module. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0023] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0024] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0025] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0026] Example 1 like Figures 1 to 15 As shown, the present invention provides a large load testing device for cranes, comprising: a crossbeam 1, a shoulder beam 2, a leg assembly 3, a base 4, a pressure testing assembly 5, a pad block 6, and a test piece 7; The base 4 is located at the bottom of the device, serving as a basic support component. The base 4 is a welded structural component with the third structural beam 402 as the main load-bearing component, and its overall shape is similar to an "I" shape. Four sets of second connecting seats 401 are welded to the upper ends of the base 4. The upper surface of each second connecting seat 401 has multiple circular holes, forming a detachable connection with the outrigger assembly 3 via fasteners. A multi-lifting point assembly 403 is welded to the middle of the base 4. The multi-lifting point assembly 403 includes a central lifting point aligned with the direction of the single lifting point assembly, and multiple lifting points on both sides perpendicular to the direction of the single lifting point assembly. The equidistant lifting points on both sides of the central single lifting point form one group, with a total of four groups. Various combinations of the multi-lifting point assembly 403, single lifting point assembly 104, and outrigger assembly 3 can meet the load testing requirements of common components of existing cranes. The maximum test load of this device can reach 800 tons, with a test load error not exceeding ±0.5%.

[0027] The support leg assembly 3 is located between the base 4 and the shoulder beam 2. The support leg assembly 3 is a box-shaped welded structure, composed of multiple layers of legs of varying heights. Each layer consists of four legs of the same height, and the combination of multiple support leg assemblies allows for height adjustments to accommodate test specimens 7 of different lengths. Flange plates are welded to the upper and lower sides of the support legs, and the entire assembly is machined after welding. The coaxiality error of the circular holes on the upper and lower flange faces is controlled within 0.3~0.6mm; otherwise, assembly accuracy will be affected, leading to a reduction in the load-bearing capacity of the device. The lower end of the combined support leg assembly is connected to the base 4, and the upper end is connected to the shoulder beam 2, both using fasteners to form a stable support frame.

[0028] The shoulder beam 2 is positioned above the outrigger assembly 3. The shoulder beam 2 is a welded structural component with the second structural beam 201 as its main load-bearing element. Two sets of first connecting seats 202 are welded to the lower ends of the shoulder beam 2. The bottom steel plate of each first connecting seat 202 has multiple round holes, which are connected to the upper flange plate of the outrigger assembly 3 via fasteners. Four sets of positioning blocks 204, with an arc-shaped surface structure, are welded to the upper part of the shoulder beam 2 near the center. These blocks are used for positioning the hydraulic cylinder 501 of the pressure testing assembly 5. Guide seats 203 are welded to both sides of each positioning block 204. These guide seats 203 are slender cylindrical structures used for guiding and positioning the crossbeam 1. The positioning blocks 204 ensure the positional stability of the hydraulic cylinder during force application, preventing slippage and ensuring vertical load transmission. The first connecting seats 202 are detachable, allowing the large testing device to be disassembled for transportation and storage, improving equipment utilization and site adaptability.

[0029] The hydraulic cylinder 501 of the pressure testing assembly 5 is mounted on the upper surface of the shoulder beam 2, while the rest is placed on the ground for convenient operation during testing. It consists of the hydraulic cylinder 501, oil pump 502, pressure gauge 503, pipelines 504, and control and display module 505. The hydraulic cylinder 501 is housed within the positioning block 204 of the shoulder beam 2. The hydraulic cylinder 501 has a built-in pressure sensor to detect the oil pressure inside the cylinder and feed it back to the control and display module 505 via the pipeline 504. The oil pump 502 is the power source for this device, providing power. The pressure gauge 503 is used to observe the working status of the oil pump 502 and detect any abnormalities. The pipeline 504 includes oil pipes, power lines, and data transmission lines for transmitting hydraulic oil, power, and test data. The control and display module 505 is the core of this device, containing two buttons, two displays, and a built-in data conversion module. The buttons operate the lifting and lowering of the hydraulic cylinder 501, and the data received from the data transmission lines is dynamically displayed on the displays after processing by the data conversion module.

[0030] The pad 6 is placed on the shoulder beam 2 and located on both sides of the hydraulic cylinder 501 of the pressure testing assembly 5. It is a rectangular load-bearing block. Its height is designed to be greater than the free height of the hydraulic cylinder 501, specifically 10-15mm higher. Otherwise, it will affect the lifting height of the hydraulic cylinder and will not be able to reach its maximum lifting force. It plays a protective and buffering role for the hydraulic cylinder 501.

[0031] A crossbeam 1 is positioned above a shoulder beam 2. The crossbeam 1 is a welded structural component with the first structural beam 103 as its main load-bearing element. A single-point lifting assembly 104 is welded to its lower part near the center. The single-point lifting assembly 104 has a centrally machined hole and reinforcing plates on both sides. The single-point lifting assembly 104 is used to connect to the upper part of the test specimen 7. Two pins 102 are respectively installed at both ends of the crossbeam 1. Lifting rings 101 are installed at the top of the pins 102 to facilitate lifting and positioning adjustments. During the test, the pins 102 at both ends of the crossbeam 1 are inserted into the guide seats 203 at both ends of the shoulder beam 2 for guidance and positioning. The cooperation between the pins 102 and the guide seats 203 achieves precise guidance and positioning, effectively preventing the crossbeam 1 from tilting during loading and avoiding unexpected eccentric loads on the test specimen 7. The lifting rings 101 make the disassembly, assembly, and positioning adjustment of the pins 102 more convenient and quick.

[0032] The working principle of this device is as follows: the crossbeam 1 is connected to the upper part of the test piece 7, the base 4 is connected to the lower part of the test piece 7, and the crossbeam 1 is lifted by the pressure testing component 5, thereby applying a tensile load to the test piece 7.

[0033] Example 2 like Figure 16 As shown, the method for conducting tests using the large load testing device for cranes in Example 1 specifically includes the following steps: Step S1: Frame assembly: According to the size of the test piece 7, adjust the number and height of the support leg assembly 3, and use fasteners to install and fix the base 4, support leg assembly 3 and shoulder beam 2 in sequence to form a stable support frame.

[0034] Step S2: Component placement: Place the hydraulic cylinders 501 of the pressure test component 5 in the positioning block 204 area of ​​the shoulder beam 2; place pads 6 on both sides of the hydraulic cylinders 501, ensuring that the height of the pads 6 is 10-15mm higher than the free height of the hydraulic cylinders 501.

[0035] Step S3: System Connection: Connect pipeline 504 to pressure test component 5 to form a closed-loop system. Press the button to start control display module 505 and observe the operating status of hydraulic cylinder 501 and whether the value displayed on pressure gauge 503 is normal, ensuring that the hydraulic system is leak-free and responsive.

[0036] Step S4: Debugging and inspection: Check the values ​​of pressure gauge 503 and control display module 505 to determine if there are any abnormalities. If there are any problems, return to S3 to readjust the system pipeline connections. If there are no problems, you can continue.

[0037] Step S5: Upper connection: Using the ear plate pin connection method, the upper part of the test piece 7 is connected to the single suspension point assembly 104 of the crossbeam 1.

[0038] Step S6: Lifting and positioning: Lift the crossbeam 1 together with the test piece 7 as a whole to the top of the shoulder beam 2, so that the pins 102 at both ends of the crossbeam are accurately inserted into the guide seats 203 of the shoulder beam.

[0039] Step S7: Lower connection: Connect the lower part of the test piece 7 to the corresponding multi-suspension point group 403 on the base 4.

[0040] Step S8: Status check: Check the connection status of the entire test piece 7 and the mechanism, focusing on whether there is any eccentricity or jamming. If there is a problem, return to S5 to readjust and ensure that the force axis is consistent.

[0041] Step S9: Initial loading: Start the control button and gradually increase the pressure through the pressure test component 5 until the load reaches 0.5 times the predetermined test load. Pause and observe the structural condition of the test piece 7 and the device.

[0042] Step S10: Full load test: After confirming that there are no abnormalities, continue to start loading and use the pressure sensor to dynamically feed back data until the target test load is reached. During this period, observe and record the condition of the test piece 7 in real time.

[0043] Step S11: End of test: After the test is completed, the pressure is released in the reverse direction and the test piece 7 is removed. The test piece 7 is inspected for deformation or cracks. Finally, the test equipment parts are sorted and stored.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large load testing device for cranes, characterized in that, include: Crossbeam (1), shoulder beam (2), leg assembly (3), base (4), pressure test assembly (5), pad (6) and test piece (7); The base (4) is located at the bottom, the lower end of the support leg assembly (3) is connected to the base (4), and the upper end is connected to the shoulder beam (2) to form a support frame; the pressure test assembly (5) is located on the upper plane of the shoulder beam (2) to provide the loading force required for the test; the pad (6) is placed on the shoulder beam (2) and located on both sides of the hydraulic cylinder (501) of the pressure test assembly (5), and the height of the pad (6) is greater than the free height of the hydraulic cylinder (501); the crossbeam (1) is located above the shoulder beam (2) and is positioned in cooperation with the shoulder beam (2) through a guide structure; the crossbeam (1) is used to connect the upper part of the test piece (7), and the base (4) is used to connect the lower part of the test piece (7). The crossbeam (1) is lifted by the pressure test assembly (5) to apply load to the test piece (7), dynamically adjust, and the condition of the test piece (7) can be observed in real time and the test load can be dynamically displayed.

2. The large load testing device for cranes according to claim 1, characterized in that, The crossbeam (1) is a welded structural component with the first structural beam (103) as the main load-bearing component. A single lifting point assembly (104) is welded to its lower part near the middle position. The single lifting point assembly (104) is used to connect the test piece (7). Pins (102) are respectively provided at both ends of the crossbeam (1). A lifting ring (101) is provided at the top of the pin (102). The shoulder beam (2) is a welded structural component with the second structural beam (201) as the main load-bearing component. Two sets of guide seats (203) are welded to both sides of the positioning block (204) above it. The guide seats (203) are circular tube structures.

3. The large load testing device for cranes according to claim 1, characterized in that, Four sets of positioning blocks (204) are welded to the upper part of the shoulder beam (2) near the middle position. The block has an arc-shaped structure. The pressure testing component (5) includes a hydraulic cylinder (501), which is placed inside the positioning block (204). Two sets of first connecting seats (202) are welded to the lower ends of the shoulder beam (2). The first connecting seats (202) are detachably connected to the support leg assembly (3) by fasteners.

4. The large load testing device for cranes according to claim 1, characterized in that, The support leg assembly (3) is a box-shaped welded structure, which is composed of multiple layers of support legs of different heights. Each layer has four support legs of the same height as a group, and the height can be adjusted by adjusting the number of support legs in the layer group. Flange plates are welded to the upper and lower planes of the support legs respectively. Fasteners are used to connect the multiple support legs and the shoulder beam (2) and the base (4).

5. A large load testing device for cranes according to claim 1, characterized in that, The base (4) is a welded structural component with the third structural beam (402) as the main load-bearing component, and its top view is similar to an I-beam structure. Four sets of second connecting seats (401) are welded above both ends of the base (4). The second connecting seats (401) are detachably connected to the support leg assembly (3) by fasteners. A multi-suspension point assembly (403) is welded in the middle of the base (4). The multi-suspension point assembly (403) includes a suspension point located in the middle and aligned with the direction of the single suspension point assembly (104), and multiple suspension points on both sides that are perpendicular to the direction of the single suspension point assembly (104).

6. A large load testing device for cranes according to claim 1, characterized in that, The pressure testing component (5) includes a hydraulic cylinder (501), an oil pump (502), a pressure gauge (503), a pipeline (504), and a control and display module (505); the hydraulic cylinder (501) has a built-in pressure sensor for detecting the oil pressure inside the cylinder and feeding it back to the control and display module (505).

7. A test method for a large load testing device for cranes as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Adjust the number of the support leg assembly (3) to meet the height requirements of the test, and use fasteners to install and fix the support leg assembly (3), base (4) and shoulder beam (2) respectively; S2. Place the hydraulic cylinder (501) of the pressure test assembly (5) in the positioning block (204) area of ​​the shoulder beam (2), and place the pad (6) on both sides of the hydraulic cylinder (501). The height of the pad (6) is 10-15mm greater than the free height of the hydraulic cylinder (501). S3. Connect the pipeline (504) to the pressure test component (5) to form a closed-loop system and debug and run it; S4. Check the values ​​of the pressure gauge (503) and control display module (505) to determine if there is any abnormality. If there is a problem, return to S3 to readjust the system pipeline (504) connection. If there is no problem, you can continue. S5. Connect the upper part of the test piece (7) to the crossbeam (1); S6. Hoist the crossbeam (1) and the test piece (7) onto the shoulder beam (2) so that the pin (102) of the crossbeam (1) is aligned and inserted into the guide seat (203) of the shoulder beam (2); S7. Connect the lower part of the test piece (7) to the corresponding lifting point of the base (4); S8. Check the connection between the entire test piece (7) and the mechanism to determine whether there is any eccentricity or jamming. If there is a problem, return to S5 to readjust. If there is no problem, you can continue. S9. Press the start button to gradually increase the pressure through the pressure test component (5) to reach 0.5 times the test load and observe the condition of the test piece (7); S10. Check whether there is any abnormality in the test piece (7). If there is any abnormality, the test should be stopped. If there is no problem, continue loading until the test load is reached and the test is completed. S11. After the test is completed, the test piece (7) is removed in reverse, and relevant inspections are carried out on it. The parts of this test device are then collected, organized, and stored.

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