Container overload and unbalanced load detection device calibration method

Abstract

The invention relates to a container overload and unbalanced load detection device calibration method, which can conveniently and quickly position each weight and prevent the weight from displacement, the gravity center of each weight is on a positioning point, the subsequent repeated measurement of the weights is avoided, the workload is saved, the working efficiency is improved, the total weight requirement can be met without stacking the weights, and the safety is higher. The method comprises the following steps: adjusting the distribution layout of weights at the bottom of a calibration box, connecting a lifting appliance of the container overload and unbalanced load detection device with the calibration box, lifting the calibration box, calculating according to the distribution position of each weight to obtain a calculated unbalanced load amount, comparing the calculated unbalanced load amount with the detected unbalanced load amount of the container overload and unbalanced load detection device, and determining the overload of the container. Wherein a plurality of positioning structure groups are uniformly distributed on a rectangular bottom plate of the calibration box along the length direction, each positioning structure group comprises a plurality of positioning structures uniformly distributed in the width direction, a coordinate origin is arranged on the rectangular bottom plate, the coordinate value of each positioning structure relative to the coordinate origin is known, and the positioning structures are detachably connected with weights.

Description

Technical Field

[0001] The invention relates to a calibration method for a container overload and unbalanced load detection device. Background Art

[0002] The gross weight and center of gravity coordinates of containers measured by the container overload and unbalanced load detection device are mainly used to prevent overloading or unbalanced load problems in transportation vehicles such as road vehicles, railway trains and sea freighters carrying containers, thereby ensuring transportation safety.

[0003] Existing overload and unbalanced load detection devices for suspended containers are mainly installed on the hanger of a front loader or a gantry crane. They can detect the weight, unbalanced weight and unbalanced load of containers when lifting containers. However, the overload and unbalanced load detection devices for suspended containers lack calibration devices and measurement value traceability methods, resulting in inconsistent calibration standards for the overload and unbalanced load detection devices for suspended containers and the inability to assess the calibration accuracy of the devices during installation and use. As a result, the acceptance calibration accuracy of the overload and unbalanced load detection devices for suspended containers is poor, the acceptance technical conditions are confusing, and it is easy to cause safety hazards in container transportation.

[0004] There are two main calibration methods in the existing technology:

[0005] First, the calibration method of the suspended container overload detection device requires placing the positions of each weight separately, and then after setting the coordinate origin, measuring the distance between each weight and the origin to determine the coordinate value. This method is very cumbersome and troublesome for the following reasons: because the calibration method needs to measure the overload indication error, lateral offset, longitudinal weight deviation, total weight indication error and the repeatability of the above data under static and dynamic conditions respectively, and each data measurement requires 10 measurements to obtain the average value, plus the large number of weights, so the coordinate position of the weights needs to be measured hundreds or thousands of times, the workload is huge, and the weights of the existing technology may have slight displacements during measurement, which will lead to inaccurate measurement, affect the accuracy of calibration, increase the workload of subsequent repeated calibration, and be very inefficient.

[0006] Secondly, in order to reduce the workload of measuring the position of each weight, multiple weights are stacked at the same coordinate position in the container to achieve eccentricity measurement. However, since the standard requires that the total weight of the container needs to be within the range of 5t-10t, 10t-15t, and 15t-20t, a calibration point is selected respectively to measure the total weight indication error. The existing single weight cannot reach this high weight. Therefore, multiple weights are often stacked on each other, which leads to an unstable center of gravity and is prone to safety accidents. Summary of the Invention

[0007] The purpose of the present invention is to provide a calibration method for a container overload and unbalanced load detection device, which can conveniently and quickly position each weight to prevent the weight from being displaced and affecting the calibration accuracy. The center of gravity of each weight is at each positioning point with fixed coordinates, eliminating the need for a large number of subsequent repeated measurements of the weight coordinate position, saving workload, and improving work efficiency. The weights do not need to be stacked to meet the total weight requirement, which is safer.

[0008] The technical solutions of the present invention are as follows:

[0009] The calibration method of the container overload detection device includes the following steps:

[0010] S10, adjusting the distribution layout of the weights at the bottom of the calibration box;

[0011] A plurality of positioning structure groups are evenly distributed along the length direction of the rectangular bottom plate of the calibration box, each positioning structure group includes a plurality of positioning structures evenly distributed along the width direction, a coordinate origin is set on the rectangular bottom plate, and the coordinate values ​​of each positioning structure relative to the coordinate origin are known;

[0012] Each weight can be detachably connected to the positioning structure, and the positioning structure can fix the weight so that the center of gravity of the weight coincides with the center of the corresponding positioning structure;

[0013] The positioning structure includes an empty positioning structure without weights and a loaded positioning structure with weights, and the number and position of the empty positioning structure are selected;

[0014] S20, connecting the lifting device of the container overload and unbalanced load detection device to the calibration box and lifting the calibration box;

[0015] S30. Calculate the eccentric load amount according to the distribution positions of the weights, and compare the calculated eccentric load amount with the eccentric load amount detected by the container overload detection device.

[0016] Based on the above solution, a further improvement is made as follows: the positioning structure is a groove provided on the rectangular base plate, and the shape and size of the groove are the same as the shape and size of the bottom of the weight. Since the weight is relatively heavy, at least several hundred or thousands of kilograms, if other complex positioning structures are used, the operation and adjustment precision requirements will be too high. However, the groove structure is used to position the weight, and the weight can be directly placed on it. On the one hand, this structure is simple and easy to use, especially for facilitating the insertion and removal of the weight. On the other hand, it takes advantage of the large weight of the weight, making it difficult for it to fall out of the groove due to its own weight, thus achieving a stable and fixed effect.

[0017] Based on the above solution, a further improvement is as follows: five positioning structure groups are arranged along the length of the rectangular base plate, each positioning structure group includes three positioning structures evenly distributed along the width direction. This layout method can not only select a standard 1-ton weight, but also easily adjust the total weight and set the offset.

[0018] On the basis of the above solution, a further improvement is made as follows: columns are provided on the four corners of the calibration box, and corner pieces are provided at the ends of the four columns for adapting and connecting with the rotary locks of the spreader.

[0019] Based on the above solution, a further improvement is to use a truck-mounted crane to carry the calibration box and weights, and use the crane on the truck-mounted crane to lift and transfer the weights. The truck-mounted crane, also known as a truck-mounted crane, is a standard product that can be used directly, avoiding the high cost of customization. The crane's crane also conveniently lifts the calibration box and the weights inside, such as adjusting the number of weights and setting the offset.

[0020] On the basis of the above solution, a further improvement is made as follows: when no offset calibration total weight is set, each loading and positioning structure is symmetrically arranged on the rectangular bottom plate.

[0021] Based on the above solution, further improvements are made as follows: the total weight of the calibration box is changed by reducing the loading and positioning structure to meet the needs of selecting calibration points within the three ranges of 5t-10t, 10t-15t, and 15t-20t.

[0022] Based on the above solution, a further improvement is made: the calibration box is made by removing the top and side panels of a standard container. This not only reduces the cost of custom processing, but also allows the calibration box to more realistically simulate the container to be measured, improving calibration accuracy.

[0023] Beneficial effects of the present invention:

[0024] 1. Convenient, fast and efficient operation: Because the present application positions the weights by disposing multiple positioning structures with known coordinate values ​​in a matrix distribution on a rectangular base plate, when the weights are placed on the positioning structures, the coordinates of the positioning structures are the coordinates of the weights, and the weight positions do not move. Therefore, no matter how many times calibration is performed, there is no need to check the coordinate values ​​of each weight, which saves a lot of measurement workload and improves calibration efficiency.

[0025] 2. Safe, stable and reliable: Because the present application distributes multiple weights on the rectangular base, multiple weights are sufficient to meet the total weight requirement for calibration, and each weight is fixed on the positioning structure. The weight of each weight is limited and does not need to be stacked on top of each other. Therefore, the center of gravity is relatively low, and it will not tip over, and it is safe and stable.

[0026] 3. High measurement and calibration accuracy: First, because the position of each weight is fixed and the coordinate value is known, there is no need for manual measurement, thus reducing the measurement error caused by multiple manual measurements; second, during the calibration process, because the weight is fixed by the positioning structure, its position will not move even slightly, thus ensuring the accuracy of the calibration results;

[0027] 4. Low cost: First, since a large number of weights can meet the total weight requirement, there is no need to customize a single weight to meet the total weight requirement, which reduces the cost of the weights; second, since there is no need to repeatedly measure the position of the weights, a lot of measurement time is saved and labor costs are also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the specific structure of a calibration box in one embodiment of the calibration method for a container overload and unbalanced load detection device of the present invention;

[0029] Figure 2 is a cross-sectional view of the calibration box;

[0030] Figure 3 is a top view of the rectangular base plate;

[0031] Figure 4 A three-dimensional diagram of the support column supporting the counterweight;

[0032] In the figure: 1- rectangular base plate, 11- groove, 12- supporting through hole, 2- column, 21- corner piece, 3- weight, 4- supporting column. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0035] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0036] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0037] An embodiment of a method for calibrating a container overload and unbalanced load detection device according to the present invention includes the following steps:

[0038] Adjust the distribution layout of the weights at the bottom of the calibration box;

[0039] Connect the lifting device of the container overload and unbalanced load detection device to the calibration box and lift the calibration box;

[0040] The calculated eccentric load is obtained based on the distribution position of each weight, and the calculated eccentric load is compared with the detected eccentric load of the container overload detection device.

[0041] The calibration box comprises a rectangular base plate, the bottom plate of which is uniformly distributed along its length, each of which includes a plurality of positioning structures uniformly distributed along its width. A coordinate origin is set on the rectangular base plate, and the coordinate values ​​of each positioning structure relative to the coordinate origin are known. Each weight is detachably connected to the positioning structure, which secures the weight so that its center of gravity coincides with the center of the corresponding positioning structure. The positioning structures include an unloaded positioning structure (without a weight) and a loaded positioning structure (with a weight), and the number and position of the unloaded positioning structures are selected. The positioning structure is a groove provided in the rectangular base plate, and the shape and size of the groove are the same as the shape and size of the bottom of the weight. Because the weight is relatively heavy, at least hundreds or thousands of kilograms, the use of other complex positioning structures would result in excessively high operational adjustment precision. However, the groove structure is used to position the weight, and the weight can be directly placed on it. On the one hand, this structure is simple and easy to use, especially convenient for placing and removing the weight. On the other hand, it takes advantage of the large weight of the weight, making it difficult for it to fall out of the groove due to its own weight, thus achieving a stable and fixed effect. Five positioning structure groups are arranged along the length of the rectangular base, each consisting of three positioning structures evenly spaced across the width. This layout allows for the selection of standard one-ton weights and facilitates adjustment of the total weight and offset. The calibration box is equipped with columns at each corner, each with corner fittings that connect to the spreader's twistlocks. A truck-mounted crane transports the calibration box and weights, and the weights are hoisted and transferred using the crane's crane. Truck-mounted cranes, also known as truck cranes, are standard products that can be used directly, eliminating the high cost of customization. The crane's crane also facilitates the handling of the calibration box and its contents, such as adjusting the number of weights and offset. When the total weight is not offset, the loading and positioning structures are arranged symmetrically on the rectangular base. By reducing the number of loading and positioning structures, the total weight of the calibration box can be adjusted to accommodate calibration points within the ranges of 5t-10t, 10t-15t, and 15t-20t. The calibration box is made by removing the top and side panels from a standard container. This reduces custom processing costs while allowing the calibration box to more realistically simulate the container being measured, improving calibration accuracy.

[0042] Specifically, if Figure 1 As shown, the calibration box includes a rectangular bottom plate 1, a column 2, and a weight 3. In this embodiment, the calibration box is modified from a standard 20-foot container, and can also be customized in other embodiments.

[0043] Specifically, the rectangular base plate 1 is a rectangular plate, and a plurality of positioning structure groups are distributed along the length direction of the rectangular plate. Each positioning structure group includes a plurality of positioning structures evenly distributed along the width direction. In this embodiment, the positioning structure is a groove 11 provided on the upper surface of the rectangular plate. The shape of the groove 11 is adapted to the shape of the bottom of the weight 3 so as to limit the position of the weight 3 after it is placed therein. Due to the heavy weight of the weight 3, the provision of the groove 11 allows the weight 3 to have only one degree of freedom in the upward direction. Due to its heavy deadweight, the weight 3 is not easy to move upward. The arrangement of the groove 11 facilitates assembly and disassembly positioning, while ensuring that the weight 3 will not move easily. The groove 11 is a rectangular groove, and the bottom of the weight 3 is a rectangular platform. There are five positioning structure groups, and each positioning structure group includes three positioning structures. Since the calibration method specified in the standard requires that the total weight needs to be within the ranges of 5-10 tons, 10-15 tons, and 15-20 tons, calibration points are selected. A 3×5 matrix arrangement is set through the positioning structure, and each weight 3 weighs 1 ton. By removing a certain number of weights 3, the total weight can be within the three weight ranges while ensuring that the arrangement of each weight 3 is uniform, so as to complete the measurement without deviation.

[0044] There are multiple weights 3, each used for detachable connection with the corresponding positioning structure. In this embodiment, there are 17 weights 3, and the corresponding grooves 11 are 3×5, totaling 15. One or more weights 3 can be selectively placed in each groove 11. When multiple weights 3 are placed, they need to be stacked. Four cylindrical support holes 12 are provided in the middle groove 11, and the four support holes 12 are evenly distributed in the groove 11. Four corresponding support columns 4 are provided, and the four support columns 4 can slide in the support holes 12 respectively. The length of the support column 4 is greater than the thickness of the rectangular base plate 1, so that the weights 3 located on the four support columns 4 can be lifted up, so that the weights 3 have a certain distance from the bottom of the groove 11, which is convenient for subsequent sudden loading of the rectangular base plate 1 to simulate hooked loading. The four support columns 4 can also be connected as a whole by a thin metal plate for easy movement and use.

[0045] There are four columns 2, which are fixed at the four corners of the rectangular base plate 1 respectively. The top of the column 2 is provided with a corner piece 21 for adapting to the rotary lock of the spreader of the container overload detection device. Several columns 2 can also be added, for example, several columns can be arranged symmetrically on the long side of the rectangular base plate 1.

[0046] The calibration box or simulated container in this application refers to a standard container that has been stripped of side panels and top panels, has grooves and support holes on the bottom panel processed, and has counterweights added so that its total weight is the same or similar to that of a real container.

[0047] The coordinate origin in this embodiment is set at the center of the base plate. In other embodiments, it can also be set at a corner of the base plate.

[0048] The positioning structure of this embodiment is a groove. In other embodiments, an electromagnet can also be used as the positioning structure to adsorb the weight on the electromagnet, or a structure with multiple limiting columns can be used to limit each weight.

[0049] The counterweights in this embodiment are ordinary weights, that is, weights used to set the bias, but their function is to replace the weight of the container flat car. They are named after their function. This embodiment has three pieces with a total weight of 3t, which is close to the weight of the container flat car.

[0050] When the calibration box and calibration equipment of the present invention are in use, the truck crane can carry the calibration box to the position to be tested, the boom can complete the lifting of the calibration box, and it is convenient to dock with the container overload detection device to be calibrated. The rotary lock on the container hoist can be directly connected with the corner pieces 21 at the four corners of the calibration box to facilitate the lifting of the calibration box. The calibration box is provided with multiple positioning structure groups on the rectangular bottom plate 1, and each group includes multiple positioning structures, so that the coordinate position of each positioning structure is fixed and measurable. The weight 3 is a standard weight. After docking it with the positioning structure, the coordinate of the weight 3 is also determined, which is convenient for subsequent calculations. The weight 3 can move freely between the positioning structures to facilitate bias setting and bias detection in the subsequent calibration process. It can be seen that compared with the calibration method in the prior art, the present application has the characteristics of convenient bias setting, convenient calculation, convenient adjustment, and convenient operation. Moreover, since the weight 3 is fixed by the positioning structure, it is not easy to move during the subsequent calibration process, so it has the characteristics of stable position, ensuring the accuracy of the subsequent calibration.

[0051] The specific calibration process is as follows:

[0052] 1. Calibration of eccentric load, indication error and repeatability

[0053] Use a standard weight that is no less than 25% of the maximum weighing capacity of a single weighing sensor of the container overload detection device to load the container. In this embodiment, a standard weight of 1 ton is used, such as Figure 3 As shown, first place 15 weights in the corresponding 15 grooves of the rectangular bottom plate. Add the weight of the calibration box itself (about 2 tons), a total of 17 tons, which can directly meet the total weight range of 15-20t. The rotary locks of the spreader of the container overload detection device are respectively matched with the corner pieces on the four corners of the calibration box. By lifting the calibration box, the loaded weights can act on the weighing sensor as much as possible, and the overload indication of the sensor is recorded. The error should not exceed the maximum allowable error of the weighing section.

[0054] Later in Figure 3In the figure shown, the weights numbered 2, 7, 9, and 14 are lifted out by a crane, and the total weight of the calibration box is 13 tons, which meets the test requirements for a total weight range of 10t-15t. Alternatively, the three weights 7, 8, and 9 are lifted out, or the four weights 2, 5, 11, and 14 are lifted out, that is, the weights in symmetrical positions are lifted out, so that the remaining weights remain in symmetrical positions to meet the test requirements without bias. When bias is required, the weights in a certain position are lifted out to make the position of the overall weights no longer symmetrical.

[0055] Similarly, continue to lift out a few weights so that the total weight is within the range of 5t-10t.

[0056] 2. Static measurement

[0057] a) Place the weights in a rectangular array within the container, i.e., the remaining weights are symmetrically positioned, with their centers of gravity close to the center (i.e., both the preset values ​​for lateral offset and longitudinal eccentricity are zero). The weights are securely reinforced using the grooves on the rectangular base plate and the weights' own weight. The detection device performs three pre-measurements (optionally without taking readings) before conducting the formal measurement. The suspended over-eccentricity detection device should record the reading 5 seconds after the calibration box has stabilized. The calibration box should be reliably on the ground for at least 5 minutes between measurements. Repeat the measurement 10 times. The error in the indication of the total weight of the calibration box is calculated using formula (1).

[0058] (1)

[0059] Where:

[0060] -Indication error, %;

[0061] - Average value of 10 measurements by the detection device, kg;

[0062] Nominal value of weight mass, kg;

[0063] —Reference value (20000), kg.

[0064] The static measurement error of the lateral offset and longitudinal offset weight is the difference between the measurement result and the preset value of the corresponding parameter. The static measurement repeatability is the difference between the maximum and minimum values ​​of the corresponding parameter measured 10 times.

[0065] b) Adjust the center of gravity of the weights in the calibration box to set the offset. For example, lift the weights at a certain position to maintain the overall rectangular arrangement. The theoretical lateral offset is between 20mm and 50mm, and the theoretical longitudinal offset is between 500kg and 2000kg (the weight of the weights within 50% of the box length must not exceed 60% of the total weight of the weights). Calculate the preset value of the lateral offset in the calibration box according to formula (2), and the preset value of the longitudinal offset according to formula (3). Record the offset information. Obtain the total weight of the calibration box, the lateral offset, and the longitudinal offset according to the measurement process in step a), and calculate the indication error and repeatability.

[0066]

[0067] Where:

[0068] -Preset value of lateral offset of calibration box, mm;

[0069] -mass of the ith weight, kg;

[0070] The horizontal coordinate of the center of gravity of the i-th weight, mm.

[0071]

[0072] Where:

[0073] --Preset value of longitudinal partial weight of container, kg;

[0074] --The vertical coordinate of the center of gravity of the i-th weight, mm;

[0075] Y--fixed distance, mm.

[0076] 3. Dynamic indication error measurement

[0077] After completing steps a) and b) of each calibration point, perform the bias setting before and after each calibration point.

[0078] Simulating normal operating procedures, 10 consecutive measurements were performed under different calibration box states (stable, varying amplitude swings, and lateral motion). The calibration box was reliably on the ground for at least 5 minutes between measurements. The indication error of the dynamic measurement of gross weight was calculated according to formula (1). The indication error of the dynamic measurement of lateral offset and longitudinal eccentricity was calculated as the difference between the measurement result of the corresponding parameter of the detection device and the preset value. The dynamic measurement repeatability was calculated as the difference between the maximum and minimum values ​​of the 10 measurement data of the corresponding parameter.

[0079] 4. F-TR lock anti-hook function test

[0080] like Figure 2 、4 As shown, support columns of the same length are installed in the support through-holes in the groove in the middle of the rectangular bottom plate, and the length of the support columns is greater than the thickness of the rectangular bottom plate. Multiple weights are stacked on the top of the four support columns. When the calibration box is lifted, the stacked weights do not contact the rectangular bottom plate at the beginning, and the weight of the weights is not loaded on the rectangular bottom plate. When it is lifted to a certain distance, so that the lower surface of the stacked weights contacts the bottom surface of the groove, the rectangular bottom plate will carry the stacked weights and move upward, that is, the weight of the stacked weights will be instantaneously loaded on the rectangular bottom plate, which can simulate the connection of the F-TR lock to the container. At this time, if the corresponding module of the container overload detection device alarms in time, the calibration result is normal. Otherwise, the calibration result is abnormal, and the corresponding detection module needs to be repaired or replaced.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the description and drawings of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for calibrating a container overload and unbalanced load detection device, characterized in that: The following steps are involved: S10, adjusting the distribution layout of the weights at the bottom of the calibration box; A plurality of positioning structure groups are evenly distributed along the length direction of the rectangular bottom plate of the calibration box, each positioning structure group includes a plurality of positioning structures evenly distributed along the width direction, a coordinate origin is set on the rectangular bottom plate, and the coordinate values ​​of each positioning structure relative to the coordinate origin are known; Each weight can be detachably connected to the positioning structure, and the positioning structure can fix the weight so that the center of gravity of the weight coincides with the center of the corresponding positioning structure; The positioning structure includes an empty positioning structure without weights and a loaded positioning structure with weights, and the number and position of the empty positioning structure are selected; S20, connecting the lifting device of the container overload and unbalanced load detection device to the calibration box and lifting the calibration box; S30. Calculate the eccentric load amount according to the distribution positions of the weights, and compare the calculated eccentric load amount with the eccentric load amount detected by the container overload detection device.

2. The container overload detection device calibration method according to claim 1, characterized in that: The positioning structure is a groove arranged on the rectangular bottom plate, and the shape and size of the groove are the same as the shape and size of the bottom of the weight.

3. The calibration method of a container overload detection device according to claim 1, characterized in that: Five positioning structure groups are arranged in the length direction of the rectangular bottom plate, and each positioning structure group includes three positioning structures evenly distributed along the width direction.

4. The container overload detection device calibration method according to claim 1, characterized in that: The four corners of the calibration box are provided with upright posts, and the ends of the four upright posts are provided with corner pieces for adapting and connecting with the rotary locks of the sling.

5. The calibration method of a container overload detection device according to claim 1, characterized in that: Use a truck-mounted crane to carry the calibration box and weights for movement, and use the crane on the truck-mounted crane to lift and transfer the weights.

6. The method for calibrating a container overload detection device according to claim 1, characterized in that: When no offset calibration total weight is set, the loading and positioning structures are symmetrically arranged on the rectangular bottom plate.

7. The container overload detection device calibration method according to claim 6, characterized in that: The total weight of the calibration box is changed by reducing the loading positioning structure to meet the needs of selecting calibration points within the three ranges of 5t-10t, 10t-15t, and 15t-20t.

8. The method for calibrating a container overload detection device according to claim 1, characterized in that: The calibration box is made by removing the top and side panels of a standard container.

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