Hoisting field type selection and checking method for chain lifting appliance

Abstract

The invention discloses a hoisting field type selection and checking method for a chain lifting appliance, and relates to the technical field of chain lifting appliances. The storage device is used for storing rigging types, rigging grades, nominal diameters, breaking force, allowable pulling force, safety coefficients, angle correction coefficients and multi-limb distribution coefficients of lifting chains and annular joint-free steel wire ropes, and the lifting chains at least comprise an M4-grade lifting chain, an S6-grade lifting chain and a T8-grade lifting chain. The annular joint-free steel wire rope is stored according to the specification in the GB / T8918-1996 steel wire rope standard; and the calculation unit is connected with the database unit and is used for calling the breaking force, the safety coefficient, the angle correction coefficient and the multi-limb distribution coefficient in the database unit after receiving the rigging category, the rigging grade, the nominal diameter, the hoisting included angle and the limb number parameters, and calculating to obtain the allowable use tension and the breaking force of the rigging under the working condition.

Description

Technical Field

[0001] This invention relates to the field of chain lifting equipment technology, specifically a method for on-site selection and verification of chain lifting equipment for hoisting operations. Background Technology

[0002] In lifting operations in metallurgy, machinery manufacturing, port loading and unloading, and construction installation, M4, S6, and T8 grade lifting chain single-limb slings and seamless circular wire ropes are widely used as lifting slings. National and industry standards specify the breaking force and safety factor for each specification of sling. However, on-site crane operators typically only know the sling grade and nominal diameter when selecting slings. They need to consult standard tables or instruction manuals to find the permissible tensile force. The calculation process involves multiple coefficients, is cumbersome, and easily leads to empirical estimations and overloading, thus causing lifting accidents.

[0003] Under current technological conditions, the following challenges exist at crane sites: First, there are numerous specifications for chains and seamless wire ropes, making it difficult for crane operators to quickly obtain the allowable tensile and breaking strength corresponding to a given grade, nominal diameter, lifting angle, and number of limbs. They often rely on experience for selection, lacking intuitive and unified judgment criteria. Second, the current standard tables involve many calculation steps, which is not conducive to team training, nor to quick verification by frontline personnel when changing rigging or adding lifting points. Manual calculation is time-consuming and prone to errors. Third, there is a lack of a comprehensive solution that can unify and solidify standard data and on-site experience formulas into gauges, and enable automatic calculation and judgment via computer, thus balancing the use of handheld gauges with systematic management. Summary of the Invention

[0004] The purpose of this invention is to provide a method for on-site selection and verification of chain lifting devices for lifting operations, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for on-site selection and verification of chain lifting slings for hoisting and lifting, the system used in this method includes the database unit, which is used to store the sling type, sling grade, nominal diameter, breaking strength, allowable tensile strength, safety factor, angle correction factor and multi-limb distribution factor of the lifting chain and the annular seamless wire rope, wherein the lifting chain includes at least M4 grade lifting chain, S6 grade lifting chain and T8 grade lifting chain, and the annular seamless wire rope is stored according to the specifications in the GB / T8918-1996 wire rope standard; The calculation unit, connected to the database unit, is used to calculate the allowable tensile force and breaking tensile force of the rigging under the working condition by calling the breaking tensile force, safety factor, angle correction factor and multi-limb distribution factor in the database unit after receiving parameters such as rigging type, rigging grade, nominal diameter, lifting angle and number of limbs. The display unit, connected to the calculation unit, is used to display the allowable tensile force and breaking tensile force output by the calculation unit in numerical and tabular form, and to provide prompts indicating whether the safety requirements are met. The card-making unit, connected to the calculation unit, generates load data tables based on the calculation results for making a simple quick calculation ruler for the tensile force of a single limb of a lifting chain, the breaking tensile force of a single limb of a lifting chain, and the tensile and breaking tensile forces of a ring-shaped seamless steel wire rope. The output is an electronic file for printing into paper calculation rulers for on-site use and lookup cards for training.

[0006] According to the above technical solution, the parameters stored in the database unit for the lifting chain satisfy the following relationship: The breaking tensile force of a single-limb lifting chain with a nominal diameter of d is denoted as Fb(d), which is obtained by fitting the breaking tensile force test data in JB / T8108.2-1999 standard for circular link chains for lifting and the occupational safety industry standard LD48-93. The safety factor of the lifting chain is denoted as SF, with a value of 4; the allowable tensile force of the lifting chain is denoted as WLL(d,β,n), which satisfies the unified calculation formula: WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, where d represents the nominal diameter of the lifting chain; Fb(d) represents the breaking tensile force of a single-limb lifting chain with a nominal diameter of d; SF represents the safety factor of the lifting chain; β represents the angle between the chain and the center line of the suspended object; f(β) represents the angle correction coefficient corresponding to the angle β; n represents the number of chain limbs; ξn represents the multi-limb distribution coefficient corresponding to the number of limbs n; after obtaining WLL(d,β,n), the calculation unit calculates the breaking tensile force Fb(d,β,n) under the corresponding working condition according to the following formula: Fb(d,β,n)=WLL(d,β,n)×SF.

[0007] According to the above technical solution, the parameters stored in the database unit for the ring-shaped seamless steel wire rope satisfy the following relationships: the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d is denoted as Fbr(d), which is determined according to the minimum breaking tensile force data in the GB / T8918-1996 steel wire rope standard; the safety factor of the ring-shaped seamless steel wire rope is denoted as SFr, with a value of 6; the allowable tensile force of the ring-shaped seamless steel wire rope is denoted as WLLr(d), which satisfies the calculation formula: WLLr(d)=Fbr(d) / SFr, where d represents the nominal diameter of the ring-shaped seamless steel wire rope; Fbr(d) represents the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d; and SFr represents the safety factor of the ring-shaped seamless steel wire rope. The calculation unit calculates WLLr(d) and Fbr(d) for each nominal diameter based on the above formula and provides the calculation results to the display unit and the card making unit to generate a load data table for a simple quick calculation ruler of the operating tensile force and breaking tensile force of the ring-shaped seamless steel wire rope.

[0008] According to the above technical solution, the values ​​of the angle correction coefficient f(β) and the multi-limb distribution coefficient ξn are determined according to the angle coefficient table and multi-limb coefficient table for the allowable tension of the lifting chain in the occupational safety industry standard LD48-93, and satisfy the following conditions: In the vertical lifting condition, the included angle β is equal to zero degrees, and f(β) is 1; in the 90-degree lifting condition, the included angle β is equal to 90 degrees, and f(β) is less than 1 and equal to the angle coefficient corresponding to 90-degree lifting in LD48-93; in the 120-degree lifting condition, the included angle β is equal to 120 degrees, and f(β) is less than the value in the 90-degree lifting condition and equal to the angle coefficient corresponding to 120-degree lifting in LD48-93; the multi-limb distribution coefficient ξn is determined according to the distribution coefficient given in LD48-93 for two-limb lifting, three-limb lifting and four-limb lifting, and the calculation unit calls f(β) and ξn simultaneously when calculating WLL(d,β,n).

[0009] According to the above technical solution, the following steps are included: Step 1: Obtain the weight of the object to be lifted, the lifting point layout plan, and the type, grade, and number of lifting slings to be used to determine the lifting conditions; Step 2: Measure the angle between each chain or each loop of seamless steel wire rope and the center line of the object being lifted, determine the angle β, and classify the angle into vertical lifting, 90-degree lifting, or 120-degree lifting conditions. Step 3: Input the rigging type, rigging grade, nominal diameter, lifting angle β, and number of limbs n into the lifting rigging rapid selection and verification system. The calculation unit reads the breaking tensile force corresponding to the nominal diameter d, the safety factor corresponding to the rigging type, the angle correction factor corresponding to the angle β, and the multi-limb distribution factor corresponding to the number of limbs n from the database unit, and calculates the allowable tensile force and breaking tensile force according to the formula. Step four: The display unit displays the allowable tensile force and breaking tensile force as numerical values ​​and tables. At the same time, it compares the allowable tensile force with the equivalent weight calculated based on the weight of the load and the lifting point layout. When the equivalent weight under each combination of working conditions is not greater than the corresponding allowable tensile force, the selected rigging is determined to meet the safety requirements. When the equivalent weight under any combination of working conditions is greater than the corresponding allowable tensile force, an overload warning is output and the user is required to reselect the rigging specifications or adjust the lifting plan.

[0010] According to the above technical solution, the step three is followed by the following steps: The card-making unit is invoked, and based on the allowable tensile force and breaking tensile force output by the calculation unit under various nominal diameters, lifting angles, and combinations of the number of limbs, the load data for each rigging category is compiled into tables, generating tables for the tensile force of a single limb of an M4 grade lifting chain, the breaking tensile force of a single limb of an M4 grade lifting chain, the tensile force of a single limb of an S6 grade lifting chain, the breaking tensile force of a single limb of an S6 grade lifting chain, the tensile force of a single limb of an T8 grade lifting chain, the breaking tensile force of a single limb of an T8 grade lifting chain, as well as tables for the tensile force and breaking tensile force of a ring-shaped seamless wire rope. The output is a printable electronic file.

[0011] According to the above technical solution, when the electronic file is printed into a paper slide rule, the nominal diameter, allowable tensile force for vertical lifting, allowable tensile force for 90-degree lifting, allowable tensile force for 120-degree lifting, and corresponding breaking tensile force are arranged into multiple columns. Alignment marks corresponding to the nominal diameter are placed on the paper slide rule, so that crane operators can directly read the allowable tensile force and breaking tensile force under each working condition after aligning with the nominal diameter on site, realizing rapid selection and verification without on-site calculation.

[0012] According to the above technical solution, the system is equipped with a sample calculation display function. This function provides at least one set of sample calculations for each rigging category and rigging grade. The sample calculations use unified symbols d, Fb(d), WLL(d,β,n), SF, f(β), ξn, Fbr(d), WLLr(d), and SFr to explain their meanings. The calculation process is displayed in the following order: First, the breaking tensile force Fb(d) or Fbr(d) corresponding to the nominal diameter d is read. Then, the safety factor is selected according to the rigging category. The permissible tensile force and breaking tensile force are calculated by counting SF or SFr, then selecting the angle correction coefficient f(β) based on the included angle β, and selecting the multi-limb distribution coefficient ξn based on the number of limbs n. Finally, the permissible tensile force and breaking tensile force are calculated by using the formulas WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, Fb(d,β,n)=WLL(d,β,n)×SF, and WLLr(d)=Fbr(d) / SFr respectively. The sample calculation is displayed on the display unit to train operators to understand the source of load data and reduce calculation errors.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention pre-calculates the allowable tensile force and breaking tensile force of different grades and specifications of rigging under various lifting angles and multi-limb working conditions based on relevant standards and empirical formulas for chains and wire ropes. The calculation results are solidified into a calculation ruler for the tensile force and breaking tensile force of single limb of various lifting chains and a simple quick calculation ruler for the tensile force and breaking tensile force of ring-shaped seamless wire ropes. It is also equipped with a set of automatic calculation methods based on a unified formula, thereby constructing an integrated solution for rapid selection and safety verification of lifting rigging. Compared to existing methods that rely on manual reference to standard tables and calculations, this invention prints the permissible tensile force and breaking tensile force of different grades of lifting chains and seamless wire ropes under typical working conditions such as vertical lifting, 90° lifting, and 120° lifting on a dedicated slide rule. This allows crane operators to select the appropriate slide rule based on the rigging grade and nominal diameter and read the value in the window to complete rigging selection and overload determination, significantly reducing reliance on personal experience and tedious calculations. Simultaneously, this invention provides a unified WLL (permissible tensile force) calculation formula and parameter system, facilitating the automatic generation of load data tables and training lookup cards through a computer system. This improves the inherent safety level of lifting operations and facilitates standardized training and on-site verification for work teams. The invention is simple in structure, low in cost, and suitable for widespread application in various types of lifting enterprises. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall process of the present invention. Detailed Implementation

[0015] 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. 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.

[0016] Please see Figure 1 This invention provides a technical solution: a method for on-site selection and verification of chain lifting slings for hoisting operations. The system used in this method includes a database unit for storing the sling type, sling grade, nominal diameter, breaking strength, allowable tensile strength, safety factor, angle correction factor, and multi-limb distribution factor of the lifting chain and the ring-shaped seamless wire rope. The lifting chain includes at least M4 grade lifting chain, S6 grade lifting chain, and T8 grade lifting chain, and the ring-shaped seamless wire rope is stored according to the specifications in the GB / T8918-1996 wire rope standard. The calculation unit, connected to the database unit, is used to calculate the allowable tensile force and breaking tensile force of the rigging under the working condition by calling the breaking tensile force, safety factor, angle correction factor and multi-limb distribution factor in the database unit after receiving parameters such as rigging type, rigging grade, nominal diameter, lifting angle and number of limbs. The display unit, connected to the calculation unit, is used to display the allowable tensile force and breaking tensile force output by the calculation unit in numerical and tabular form, and to provide prompts indicating whether the safety requirements are met. The card-making unit, connected to the calculation unit, is used to generate load data tables based on the calculation results for making a simple quick calculation ruler for the tensile force of a single limb of a lifting chain, the breaking tensile force of a single limb of a lifting chain, and the tensile force and breaking tensile force of a ring-shaped seamless steel wire rope. The output is an electronic file, which is used to print paper calculation rulers for on-site use and lookup cards for training. The parameters stored in the database unit for the lifting chain satisfy the following relationship: The breaking tensile force of a single-limb lifting chain with a nominal diameter of d is denoted as Fb(d), which is obtained by fitting the breaking tensile force test data in JB / T8108.2-1999 standard for circular link chains for lifting and the occupational safety industry standard LD48-93. The safety factor of the lifting chain is denoted as SF, with a value of 4; the allowable tensile force of the lifting chain is denoted as WLL(d,β,n), which satisfies the unified calculation formula: WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, where d represents the nominal diameter of the lifting chain; Fb(d) represents the breaking tensile force of a single-limb lifting chain with a nominal diameter of d; SF represents the safety factor of the lifting chain; β represents the angle between the chain and the center line of the suspended object; f(β) represents the angle correction coefficient corresponding to the angle β; n represents the number of chain limbs; ξn represents the multi-limb distribution coefficient corresponding to the number of limbs n; after obtaining WLL(d,β,n), the calculation unit calculates the breaking tensile force Fb(d,β,n) under the corresponding working condition according to the following formula: Fb(d,β,n)=WLL(d,β,n)×SF; The parameters stored in the database unit for the ring-shaped seamless steel wire rope satisfy the following relationships: the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d is denoted as Fbr(d), which is determined according to the minimum breaking tensile force data in the GB / T8918-1996 steel wire rope standard; the safety factor of the ring-shaped seamless steel wire rope is denoted as SFr, with a value of 6; the allowable tensile force of the ring-shaped seamless steel wire rope is denoted as WLLr(d), which satisfies the calculation formula: WLLr(d)=Fbr(d) / SFr, where d represents the nominal diameter of the ring-shaped seamless steel wire rope; Fbr(d) represents the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d; and SFr represents the safety factor of the ring-shaped seamless steel wire rope. The calculation unit calculates WLLr(d) and Fbr(d) for each nominal diameter based on the above formula and provides the calculation results to the display unit and the card making unit to generate a load data table for the simple quick calculation ruler of the operating tensile force and breaking tensile force of the ring-shaped seamless steel wire rope. The values ​​of the angle correction coefficient f(β) and the multi-limb distribution coefficient ξn are determined according to the angle coefficient table and multi-limb coefficient table for the permissible tension of the lifting chain in the occupational safety industry standard LD48-93, and satisfy the following conditions: In the vertical lifting condition, the included angle β is equal to zero degrees, and f(β) is 1; in the 90-degree lifting condition, the included angle β is equal to 90 degrees, and f(β) is less than 1 and equal to the angle coefficient corresponding to 90-degree lifting in LD48-93; in the 120-degree lifting condition, the included angle β is equal to 120 degrees, and f(β) is less than the value in the 90-degree lifting condition and equal to the angle coefficient corresponding to 120-degree lifting in LD48-93; the multi-limb distribution coefficient ξn is determined according to the distribution coefficients given in LD48-93 for two-limb lifting, three-limb lifting and four-limb lifting. The calculation unit calls f(β) and ξn simultaneously when calculating WLL(d,β,n); All these scattered coefficients are standardized in the database, and using a unified logic of breaking strength ÷ safety factor × angle correction factor × multi-limb distribution factor, the permissible tensile force and corresponding breaking strength are directly generated for any diameter, any typical included angle, and any combination of limbs. In this solution, this step is the calculation core of the entire system, providing completely consistent load data for subsequent system selection, field gauges, and training card production. Its originality lies in the fact that it does not simply copy standard tables, but abstracts the chain strength standard, angle correction rules, and multi-limb distribution rules into a unified parameterized model. Any grade, specification, and working condition can be automatically generated by inputting only a few parameters. It truly achieves a single formula that connects all combinations, integrating multiple tables and algorithms into a concise yet rigorous calculation link, which is not only easy to implement but also easy to expand to new grades and working conditions in the future.

[0017] The breaking tensile force (Fb_r(d)) and safety factor (SF_r=6) of the wire rope are explicitly written into the database. Using the same breaking tensile force ÷ safety factor = allowable tensile force model as for chains, the allowable tensile force of the loop-type seamless wire rope and the WLL of the chain are generated and displayed under the same system and symbol system. This step plays a role in cross-category unification in this solution, allowing chains and wire ropes to be compared, selected, and verified on the same platform. Its originality lies not in simply adding another type of rigging, but in unifying two major categories of rigging with different standards and safety factors into a single algorithm and data structure. This allows the management system, slide rule, and training materials to output a consistent solution, resolving the long-standing confusion in the field where chains were calculated using one algorithm and wire ropes were bent using another set of empirical methods.

[0018] Includes the following steps: Step 1: Obtain the weight of the object to be lifted, the lifting point layout plan, and the type, grade, and number of lifting slings to be used to determine the lifting conditions; Step 2: Measure the angle between each chain or each loop of seamless steel wire rope and the center line of the object being lifted, determine the angle β, and classify the angle into vertical lifting, 90-degree lifting, or 120-degree lifting conditions. Step 3: Input the rigging type, rigging grade, nominal diameter, lifting angle β, and number of limbs n into the lifting rigging rapid selection and verification system. The calculation unit reads the breaking tensile force corresponding to the nominal diameter d, the safety factor corresponding to the rigging type, the angle correction factor corresponding to the angle β, and the multi-limb distribution factor corresponding to the number of limbs n from the database unit, and calculates the allowable tensile force and breaking tensile force according to the formula. Step 4: The display unit displays the allowable tensile force and breaking tensile force as numerical values ​​and tables. At the same time, it compares the allowable tensile force with the equivalent weight calculated based on the weight of the load and the arrangement of the lifting points. When the equivalent weight under each combination of working conditions is not greater than the corresponding allowable tensile force, the selected rigging is determined to meet the safety requirements. When the equivalent weight under any combination of working conditions is greater than the corresponding allowable tensile force, an overload warning is output and the user is required to reselect the rigging specifications or adjust the lifting plan. Under conventional methods, even with a given allowable tensile force, on-site operations often only compare the load's own weight with the rated load under a specific condition, easily overlooking the effects of multiple lifting points, angles, and the worst-case scenarios for different combinations of conditions. Safety margin assessments vary depending on individual habits. The principle of this step is: first, through steps one and two, the load's weight, lifting point arrangement, and angles are summarized into clear lifting conditions. Then, the allowable tensile force for each combination is calculated in the system using formulas. Finally, a judgment is made based on the hard condition that the equivalent weight corresponding to all combinations of conditions is less than or equal to the corresponding allowable tensile force. If any condition fails to meet this condition, an overload warning is output. In this solution, this verification step is the crucial link between calculating numbers and making decisions, directly determining whether the selection result is considered safe. Compared to conventional manual calculations, the originality of this step lies in: fixing multi-factor safety verification into a rigorous comparative logic, eliminating the ambiguity of only looking at the most intuitive conditions or estimating based on experience, compressing complex safety judgments into a clear rule that the system can execute, allowing non-experts to perform expert-level safety verification.

[0019] Step three is followed by the following steps: The card-making unit is invoked, and based on the allowable tensile force and breaking tensile force output by the calculation unit under various nominal diameters, lifting angles, and combinations of the number of limbs, the load data for each rigging category is organized into tables, generating tables for the tensile force of a single limb of an M4 grade lifting chain, the breaking tensile force of a single limb of an M4 grade lifting chain, the tensile force of a single limb of an S6 grade lifting chain, the breaking tensile force of a single limb of an S6 grade lifting chain, the tensile force of a single limb of an T8 grade lifting chain, the breaking tensile force of a single limb of an T8 grade lifting chain, as well as tables for the tensile force and breaking tensile force of a ring-shaped seamless wire rope, and outputting them as printable electronic files. When the electronic file is printed into a paper slide rule, the nominal diameter, allowable tensile force for vertical lifting, allowable tensile force for 90-degree lifting, allowable tensile force for 120-degree lifting, and corresponding breaking tensile force are arranged in multiple columns. Alignment marks corresponding to the nominal diameter are placed on the paper slide rule, so that crane operators can directly read the allowable tensile force and breaking tensile force for each working condition after aligning with the nominal diameter on site, achieving rapid selection and verification without on-site calculation. The system includes a sample calculation display function. This function provides at least one sample calculation for each rigging category and grade. The sample calculation uses standardized symbols d, Fb(d), WLL(d,β,n), SF, f(β), ξn, Fbr(d), WLLr(d), and SFr to explain their meanings. The calculation process is displayed in the following order: First, the breaking tensile force Fb(d) or Fbr(d) corresponding to the nominal diameter d is read. Then, the safety factor SF or SFr is selected according to the rigging category. Next, the angle correction factor f(β) is selected according to the included angle β. Then, the multi-limb distribution factor ξn is selected according to the number of limbs n. Finally, the allowable tensile force and breaking tensile force are obtained according to the formulas WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, Fb(d,β,n)=WLL(d,β,n)×SF, and WLLr(d)=Fbr(d) / SFr. The sample calculation is displayed on the display unit to train operators to understand the source of load data and reduce calculation errors.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0021] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for on-site selection and verification of chain lifting slings for hoisting operations, characterized in that: The system used in this method includes the database unit, which stores the rigging type, rigging grade, nominal diameter, breaking strength, allowable tensile strength, safety factor, angle correction factor, and multi-limb distribution factor of the lifting chain and the ring-shaped seamless wire rope. The lifting chain includes at least M4 grade lifting chain, S6 grade lifting chain, and T8 grade lifting chain, and the ring-shaped seamless wire rope is stored according to the specifications in the GB / T8918-1996 wire rope standard. The calculation unit, connected to the database unit, is used to calculate the allowable tensile force and breaking tensile force of the rigging under the working condition by calling the breaking tensile force, safety factor, angle correction factor and multi-limb distribution factor in the database unit after receiving parameters such as rigging type, rigging grade, nominal diameter, lifting angle and number of limbs. The display unit, connected to the calculation unit, is used to display the allowable tensile force and breaking tensile force output by the calculation unit in numerical and tabular form, and to provide prompts indicating whether the safety requirements are met. The card-making unit, connected to the calculation unit, generates load data tables based on the calculation results for making a simple quick calculation ruler for the tensile force of a single limb of a lifting chain, the breaking tensile force of a single limb of a lifting chain, and the tensile and breaking tensile forces of a ring-shaped seamless steel wire rope. The output is an electronic file for printing into paper calculation rulers for on-site use and lookup cards for training.

2. The method for on-site selection and verification of chain lifting devices for hoisting operations according to claim 1, characterized in that: The parameters stored in the database unit for the lifting chain satisfy the following relationship: The breaking tensile force of a single-limb lifting chain with a nominal diameter of d is denoted as Fb(d), which is obtained by fitting the breaking tensile force test data in JB / T8108.2-1999 standard for circular link chains for lifting and the occupational safety industry standard LD48-93. The safety factor of the lifting chain is denoted as SF, with a value of 4; the allowable tensile force of the lifting chain is denoted as WLL(d,β,n), which satisfies the unified calculation formula: WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, where d represents the nominal diameter of the lifting chain; Fb(d) represents the breaking tensile force of a single-limb lifting chain with a nominal diameter of d; SF represents the safety factor of the lifting chain; β represents the angle between the chain and the center line of the suspended object; f(β) represents the angle correction coefficient corresponding to the angle β; n represents the number of chain limbs; ξn represents the multi-limb distribution coefficient corresponding to the number of limbs n; after obtaining WLL(d,β,n), the calculation unit calculates the breaking tensile force Fb(d,β,n) under the corresponding working condition according to the following formula: Fb(d,β,n)=WLL(d,β,n)×SF.

3. The method for on-site selection and verification of chain lifting devices for hoisting and lifting, as described in claim 2, is characterized in that: The parameters stored in the database unit for the ring-shaped seamless steel wire rope satisfy the following relationships: the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d is denoted as Fbr(d), which is determined according to the minimum breaking tensile force data in the GB / T8918-1996 steel wire rope standard; the safety factor of the ring-shaped seamless steel wire rope is denoted as SFr, with a value of 6; the allowable tensile force of the ring-shaped seamless steel wire rope is denoted as WLLr(d), which satisfies the calculation formula: WLLr(d)=Fbr(d) / SFr, where d represents the nominal diameter of the ring-shaped seamless steel wire rope; Fbr(d) represents the breaking tensile force of the ring-shaped seamless steel wire rope with a nominal diameter of d; and SFr represents the safety factor of the ring-shaped seamless steel wire rope. The calculation unit calculates WLLr(d) and Fbr(d) for each nominal diameter based on the above formula and provides the calculation results to the display unit and the card making unit to generate a load data table for the simple quick calculation ruler of the operating tensile force and breaking tensile force of the ring-shaped seamless steel wire rope.

4. The method for on-site selection and verification of chain lifting devices according to claim 3, characterized in that: The values ​​of the angle correction coefficient f(β) and the multi-limb distribution coefficient ξn are determined according to the angle coefficient table and multi-limb coefficient table for the permissible tension of the lifting chain in the occupational safety industry standard LD48-93, and satisfy the following conditions: In the vertical lifting condition, the included angle β is equal to zero degrees, and f(β) is 1; in the 90-degree lifting condition, the included angle β is equal to 90 degrees, and f(β) is less than 1 and equal to the angle coefficient corresponding to 90-degree lifting in LD48-93; in the 120-degree lifting condition, the included angle β is equal to 120 degrees, and f(β) is less than the value in the 90-degree lifting condition and equal to the angle coefficient corresponding to 120-degree lifting in LD48-93; the multi-limb distribution coefficient ξn is determined according to the distribution coefficients given in LD48-93 for two-limb lifting, three-limb lifting and four-limb lifting, and the calculation unit calls f(β) and ξn simultaneously when calculating WLL(d,β,n).

5. The method for on-site selection and verification of chain lifting devices for hoisting and lifting, as described in claim 4, is characterized in that: Includes the following steps: Step 1: Obtain the weight of the object to be lifted, the lifting point layout plan, and the type, grade, and number of lifting slings to be used to determine the lifting conditions; Step 2: Measure the angle between each chain or each loop of seamless steel wire rope and the center line of the object being lifted, determine the angle β, and classify the angle into vertical lifting, 90-degree lifting, or 120-degree lifting conditions. Step 3: Input the rigging type, rigging grade, nominal diameter, lifting angle β, and number of limbs n into the lifting rigging rapid selection and verification system. The calculation unit reads the breaking tensile force corresponding to the nominal diameter d, the safety factor corresponding to the rigging type, the angle correction factor corresponding to the angle β, and the multi-limb distribution factor corresponding to the number of limbs n from the database unit, and calculates the allowable tensile force and breaking tensile force according to the formula. Step four: The display unit displays the allowable tensile force and breaking tensile force as numerical values ​​and tables. At the same time, it compares the allowable tensile force with the equivalent weight calculated based on the weight of the load and the lifting point layout. When the equivalent weight under each combination of working conditions is not greater than the corresponding allowable tensile force, the selected rigging is determined to meet the safety requirements. When the equivalent weight under any combination of working conditions is greater than the corresponding allowable tensile force, an overload warning is output and the user is required to reselect the rigging specifications or adjust the lifting plan.

6. The method for on-site selection and verification of chain lifting devices for hoisting and lifting, as described in claim 5, is characterized in that: Following step three, the following steps are also included: The card-making unit is invoked, and based on the allowable tensile force and breaking tensile force output by the calculation unit under various nominal diameters, lifting angles, and combinations of the number of limbs, the load data for each rigging category is compiled into tables, generating tables for the tensile force of a single limb of an M4 grade lifting chain, the breaking tensile force of a single limb of an M4 grade lifting chain, the tensile force of a single limb of an S6 grade lifting chain, the breaking tensile force of a single limb of an S6 grade lifting chain, the tensile force of a single limb of an T8 grade lifting chain, the breaking tensile force of a single limb of an T8 grade lifting chain, as well as tables for the tensile force and breaking tensile force of a ring-shaped seamless wire rope. The output is a printable electronic file.

7. The method for on-site selection and verification of chain lifting devices for hoisting and lifting, as described in claim 6, is characterized in that: When the electronic file is printed into a paper slide rule, the nominal diameter, allowable tensile force for vertical lifting, allowable tensile force for 90-degree lifting, allowable tensile force for 120-degree lifting, and corresponding breaking tensile force are arranged in multiple columns. Alignment marks corresponding to the nominal diameter are placed on the paper slide rule, so that crane operators can directly read the allowable tensile force and breaking tensile force for each working condition after aligning with the nominal diameter on site, realizing rapid selection and verification without on-site calculation.

8. The method for on-site selection and verification of chain lifting devices for hoisting and lifting according to claim 7, characterized in that: The system is equipped with a sample calculation display function. This function provides at least one set of sample calculations for each rigging category and rigging grade. The sample calculations use unified symbols d, Fb(d), WLL(d,β,n), SF, f(β), ξn, Fbr(d), WLLr(d), and SFr to explain their meanings. The calculation process is displayed in the following order: First, the breaking tensile force Fb(d) or Fbr(d) corresponding to the nominal diameter d is read. Then, the safety factor SF or SFr is selected according to the rigging category. Next, the angle correction factor f(β) is selected according to the included angle β. Then, the multi-limb distribution factor ξn is selected according to the number of limbs n. Finally, the allowable tensile force and breaking tensile force are obtained according to the formulas WLL(d,β,n)=Fb(d) / SF×f(β)×ξn, Fb(d,β,n)=WLL(d,β,n)×SF, and WLLr(d)=Fbr(d) / SFr. The sample calculations are displayed on the display unit to train operators to understand the source of load data and reduce calculation errors.

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