A method for determining a hoist wire rope multiplication factor for a crane

Abstract

This invention discloses a method for determining the lifting wire rope ratio of a crane, wherein: 1) the lifting ratio is not greater than the maximum lifting ratio n determined by the number of pulleys in the boom pulley block and the hook pulley block. max1 ;2) The tension of a single rope shall not exceed the maximum tension T of the wire rope that the winch can provide. max The corresponding multiplier is the minimum multiplier n determined by the maximum single rope tension. min2 The lifting ratio shall not be less than the maximum single-rope tension T of the wire rope. max The hoisting ratio at that time; 3) The remaining number of layers of the hoisting wire rope shall not be greater than the maximum allowable remaining number of layers of the hoisting wire rope and shall not be less than 0, m Smax The minimum magnification n is determined by the number of remaining layers of the hoisting wire rope. min3 m Smin The maximum magnification n is determined by the number of remaining layers of the hoisting wire rope. max3 The lifting ratio is not greater than the lifting ratio of the minimum allowable remaining number of layers of the hoisting wire rope and not less than the lifting ratio of the maximum allowable remaining number of layers of the hoisting wire rope; 4) Considering conditions 1), 2), and 3), the method for determining the lifting wire rope ratio n is MAX[n min2 n min3 ]≤n≤MIN[n max1 n max3 ].

Description

Technical Field

[0001] This invention relates to the field of cranes, and more particularly to a method for determining the lifting wire rope ratio of a crane. Background Technology

[0002] Crane: A machine used for lifting and moving heavy objects. Boom: A component on a crane located between the main unit and the hook, used to support the load. Winch: A mechanism on a crane used to wind a wire rope and provide tension to the hook through the wire rope. Hook: A device on a crane used to hook and lift heavy objects. Pulley Block: A device on a crane consisting of one or more pulleys that allows a larger pulling force to be obtained with a smaller single rope tension.

[0003] The hoisting system of a crane typically consists of a winch, wire rope, boom pulley block, and hook.

[0004] When the lifting capacity is small, a single winch is generally used for lifting. The winch is wound with a wire rope, which is guided by a pulley and wound between the boom pulley block and the hook pulley block in a set winding manner. The hook can carry heavy objects. By rotating the winch to wind up and down the wire rope, the distance between the boom pulley block and the hook is changed, thereby realizing the lifting and lowering of heavy objects.

[0005] When lifting a large load, double or multiple winches are often used. Each winch is wound with a wire rope, which is guided by a pulley and wound in a predetermined manner between the pulley blocks on one side of the boom and the pulley blocks on the other side of the hook. The winch is also wound with a wire rope, which is guided by a pulley and wound in a predetermined manner between the pulley blocks on the other side of the boom and the pulley blocks on the other side of the hook. The hook and the two pulley blocks are connected to the same hook head, forming a split pulley block hook.

[0006] The number of hoisting wire ropes wound between the boom pulley block and the hook pulley block is called the ratio. For single-winch hoisting, the number of hoisting wire ropes between the boom pulley block and the hook pulley block is 6, which is a ratio of 6. For double-winch hoisting, the number of wire ropes wound between the boom pulley block and the hook pulley block for each winch is 6, which is a ratio of 2 × 6, where 2 represents the number of winches.

[0007] Since the maximum single-rope tension Tmax that the winch can provide is a fixed value, in order to increase the lifting capacity, that is, to increase the tension between the boom pulley block and the hook, the number of lifting wire ropes wound between the boom pulley block and the hook pulley block is usually increased, that is, the multiplier is increased.

[0008] The commonly used method for determining the multiplier is:

[0009] 1. Based on the number of pulleys in the boom pulley block and hook pulley block, and the required lifting capacity, assume a ratio n1, and calculate the efficiency η of the pulley block at this ratio. Z1 :

[0010] η Z1 =η D (1-η n1 ) / [n1×(1-η)] (1)

[0011] In the formula, η is the efficiency of a single pulley; n1 is the lifting ratio; and D is the number of guide pulleys between the boom pulley block and the winch.

[0012] 2. Calculate the single rope tension T1 of the hoisting wire rope at this ratio:

[0013] T1=Q / (n1η Z1 (2)

[0014] In the formula, Q is the maximum load under the boom pulley block.

[0015] If T1 > T max Then, assume the multiplier is n2, n2 = n1 + 1, change n1 in equations (1) and (2) to n2, and calculate T2. If T2 > T max Let n2 = n1 + 2, calculate T2, and continue until T2 ≤ T max At this point, n2 is determined as the lifting ratio for that lifting capacity.

[0016] If T1 = T max Then n1 is determined as the lifting ratio of the lifting capacity.

[0017] If T1 < T max Then, assume the multiplier is n2, n2 = n1 - 1, change n1 in equations (1) and (2) to n2, and calculate T2. If T2 < T max Let n2 = n1 - 2, calculate T2, and continue until T2 ≥ T. max If T2 > T max Then the corresponding n2+1 is determined as the lifting ratio for that lifting capacity; if T2 = T max Then, the corresponding n2 is determined as the lifting ratio of the lifting weight.

[0018] However, existing technologies primarily consider the lifting capacity determined by the single-rope tension and lifting ratio to ensure the winch is not overloaded, and this is on the premise that the remaining wire rope in the winch is in a pre-tensioned state when the hook reaches the position of the load. However, they do not consider the number of layers of remaining wire rope in the winch when the hook reaches the load. If there are many layers of remaining wire rope in the winch, and the remaining wire rope is not pre-tensioned, it will be in a slack state. When lifting a heavy load, the wire rope wound into the winch will be in a taut state and will get caught in the slack remaining wire rope, causing irregular entanglement, damage, or even breakage of the wire rope, leading to an accident. Furthermore, pre-tensioning the remaining wire rope is time-consuming and labor-intensive, and crane users are generally unwilling to pre-tension before each lifting operation, or even rarely pre-tension it at all.

[0019] Therefore, it is necessary to develop a new method for determining the lifting wire rope ratio of cranes, to reasonably determine the lifting ratio, and to avoid irregular winding of the winch wire rope. Summary of the Invention

[0020] Purpose of the invention: To address the shortcomings and defects of existing technologies, this invention provides a method for determining the lifting wire rope ratio of a crane. By reasonably determining the lifting ratio, irregular winding of the winch wire rope is avoided, and the method eliminates the need for pre-tensioning of the remaining winch wire rope. This ensures that the tension of a single wire rope does not exceed its maximum single rope tension, and that the number of layers of remaining winch wire rope does not exceed the safe number of layers, thereby preventing irregular winding of the winch wire rope and ensuring lifting safety.

[0021] Technical solution: The present invention provides a method for determining the lifting wire rope ratio of a crane, characterized in that the following conditions are met simultaneously:

[0022] 1) The lifting ratio shall not exceed the maximum lifting ratio n determined by the number of pulleys in the boom pulley block and hook pulley block. max1 That is, n≤n max1 ;

[0023] 2) The tension of a single rope shall not exceed the maximum tension T of the wire rope that the winch can provide. max The corresponding multiplier is the minimum multiplier n determined by the maximum single rope tension. min2 That is, T≤T max , n≥n min2 The lifting ratio shall not be less than the maximum single-rope tension T of the wire rope. max Lifting ratio at that time;

[0024] 3) The remaining number of layers of the hoisting wire rope shall not exceed the maximum allowable remaining number of layers of the hoisting wire rope and shall not be less than 0.m Smax The minimum magnification n is determined by the number of remaining layers of the hoisting wire rope. min3 m Smin The maximum magnification n is determined by the number of remaining layers of the hoisting wire rope. max3 , i.e. m S≤m Smax And m S ≥m Smin =0, n min3 ≤n≤n max3 The lifting ratio shall not be greater than the lifting ratio of the minimum allowable remaining number of layers of the winch wire rope and shall not be less than the lifting ratio of the maximum allowable remaining number of layers of the winch wire rope.

[0025] 4) Considering conditions 1), 2), and 3), the method for determining the hoisting wire rope ratio n is MAX[n]. min2 n min3 ]≤n≤MIN[n max1 n max3 ].

[0026] Among them, n in condition 1) max1 The method for determining it is as follows:

[0027] 1) If the number of pulleys in the boom pulley block is less than or equal to the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It is equal to twice the minimum number of pulleys in the boom pulley block or hook pulley block, i.e., n max1 =n Hmax =2*z B =2*z G Therefore, n≤n max1 =n Hmax That is, n≤22*z B =2*z G ;

[0028] 2) If the number of pulleys in the boom pulley block is greater than the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It equals twice the minimum number of pulleys in the hook pulley system plus 1, i.e., n max1 =n Hmax =2*z G +1, therefore n≤n max1 =n Hmax That is, n≤2*z G +1;

[0029] Where n H The lifting ratio, z, is determined by the number of pulleys in the boom pulley block and the hook pulley block. B z is the number of pulleys in the boom pulley system. G This refers to the number of pulleys in the hook pulley block.

[0030] Among them, n in condition 2) min2 The method for determining it is as follows:

[0031] Based on the number of pulleys in the boom pulley block and hook pulley block, and the required lifting capacity, we first assume a multiplier n1, where n1 ≤ n max1 The lifting ratio n is assumed to be the lifting capacity to be achieved. Q Not less than the ratio of lifting capacity to maximum single-rope tension, i.e., n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; therefore, it is assumed that the range of values ​​for n1 is n Qmin ≤n1≤n Hmax Where Q is the maximum load under the boom pulley block when the load is lifted off the ground, and n Q The lifting ratio is the maximum load under the boom pulley block when the load is lifted off the ground.

[0032] Calculate the efficiency η of the pulley system with the assumed n1 ratio. Z1 :

[0033] η Z1 =η D (1-η n1 ) / [n1×(1-η)] (1)

[0034] Where η is the efficiency of a single pulley, and D is the number of guide pulleys between the boom pulley block and the winch;

[0035] Calculate the single-rope tension T1 of the hoisting wire rope at the n1 ratio:

[0036] T1=Q / (n1η Z1 (2)

[0037] If T1 > T max Then, assume the multiplier is n2, n2 = n1 + 1, and use equation (1) to calculate T2 by changing n1 to n2 and T1 to T2 in equations (1) and (2); if T2 > T max Let n3 = n1 + 2, calculate T3, and so on, until T... x ≤T max ; the corresponding n at this time x Then it is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n x ;

[0038] If T1 = T max Then n1 is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n1;

[0039] If T1 < T maxThen, assume the multiplier is n2, n2 = n1 - 1, change n1 to n2 in equations (1) and (2), change T1 to T2, and calculate T2; if T2 < T max Let n3 = n1 - 2, calculate T3, and so on, until n x When the multiplier is T x ≥T max If T x >T max Then the corresponding (n x +1) is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n x +1; if T x =T max Then the corresponding n x The lifting ratio, n, is determined as the lifting capacity. min2 =n x .

[0040] Among them, n in condition 3) min3 n max3 The method for determining it is as follows:

[0041] Calculate the maximum allowable remaining length L of the hoisting wire rope Ymax Determine the maximum allowable number of remaining layers i of the hoisting wire rope based on the structure of the hoist. max Maximum permissible remaining length L of the hoisting wire rope Ymax =L J1 +L J2 +…+L Ji ; where L J1 L is the length of the wire rope that can be wound in the first layer (i.e., the bottom layer) of the hoist; J2 The length of wire rope that can be wound in the second layer (i.e., the second bottom layer) of the winch is L. Ji The length of the wire rope that can be wound around the i-th layer of the winch is L. Ji ;

[0042] Calculate the minimum length L of the wire rope required to pull out the winch when the load is off the ground. Cmin :L Cmin =L S -L ymax ; where L S This refers to the length of the lifting wire rope;

[0043] Calculate the minimum lifting ratio n min3 :

[0044] L Cmin =L JD +L DB +n Smin *π*R B / 2+n Smin *π*RG / 2+n Smin *H;

[0045] n Smin =(L Cmin -L JD -L DB ) / (π*R B / 2+π*R G / 2+H);

[0046] n Smin If the calculated value is a decimal, round it up. The rounded value n Smin That is, n min3 ;where R B R is the diameter of the pulley in the boom pulley block. G Where L is the diameter of the hook pulley block, H is the distance between the center line of the boom pulley block and the center line of the hook pulley block when the load is lifted off the ground, and L is the diameter of the hook pulley block. JD L is the center distance from the winch to the guide pulley. DB The center distance between the guide pulley and the boom pulley block;

[0047] Calculate the maximum lifting ratio n max3 :

[0048] Let L Ymin =0, then L Cmax =L S ;

[0049] L S =L JD +L DB +n Smax *π*R B / 2+n Tmax *π*R G / 2+n Tmax *H;

[0050] n Smax =(L S -L JD -L DB ) / (π*R B / 2+π*R G / 2+H);

[0051] n Smax If the calculated value is a decimal, round it down. The rounded value n Smax That is, n max3 .

[0052] For cases where multiple winches are used for joint lifting, each winch is calculated separately.

[0053] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention introduces a method for determining the lifting ratio of a crane to ensure that the wire rope tension is not overloaded, and to ensure that the winch does not become tangled without pre-tensioning the remaining wire rope. This ensures that the lifting system is not overloaded, does not become tangled, and improves operational efficiency. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of a single-coil hoisting structure;

[0055] Figure 2 This is a schematic diagram of a double-winch lifting structure;

[0056] Figure 3 This is a diagram showing the winding of the crane hoisting wire rope according to the present invention. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] The method for determining the lifting wire rope ratio of a crane according to the present invention is characterized by simultaneously satisfying the following conditions:

[0059] 1) The lifting ratio shall not exceed the maximum lifting ratio n determined by the number of pulleys in the boom pulley block and hook pulley block. max1 That is, n≤n max1 ;

[0060] 2) The tension of a single rope shall not exceed the maximum tension T of the wire rope that the winch can provide. max The corresponding multiplier is the minimum multiplier n determined by the maximum single rope tension. min2 That is, T≤T max , n≥n min2 The lifting ratio shall not be less than the maximum single-rope tension T of the wire rope. max Lifting ratio at that time;

[0061] 3) The remaining number of layers of the hoisting wire rope shall not exceed the maximum allowable remaining number of layers of the hoisting wire rope and shall not be less than 0.m Smax The minimum magnification n is determined by the number of remaining layers of the hoisting wire rope. min3 m Smin The maximum magnification n is determined by the number of remaining layers of the hoisting wire rope. max3 , i.e. m S ≤m Smax And m S ≥m Smin =0, n min3 ≤n≤n max3 The lifting ratio shall not be greater than the lifting ratio of the minimum allowable remaining number of layers of the winch wire rope and shall not be less than the lifting ratio of the maximum allowable remaining number of layers of the winch wire rope.

[0062] 4) Considering conditions 1), 2), and 3), the method for determining the hoisting wire rope ratio n is MAX[n]. min2 n min3 ]≤n≤MIN[n max1 n max3 ].

[0063] Among them, n in condition 1) max1 The method for determining it is as follows:

[0064] 1) If the number of pulleys in the boom pulley block is less than or equal to the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It is equal to twice the minimum number of pulleys in the boom pulley block or hook pulley block, i.e., n max1 =n Hmax =2*z B =2*z G Therefore, n≤n max1 =n Hmax That is, n≤22*z B =2*z G ;

[0065] 2) If the number of pulleys in the boom pulley block is greater than the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It equals twice the minimum number of pulleys in the hook pulley system plus 1, i.e., n max1 =n Hmax =2*z G +1, therefore n≤n max1 =n Hmax That is, n≤2*z G +1;

[0066] Where n H The lifting ratio, z, is determined by the number of pulleys in the boom pulley block and the hook pulley block. B z is the number of pulleys in the boom pulley system. G This refers to the number of pulleys in the hook pulley block.

[0067] Among them, n in condition 2) min2 The method for determining it is as follows:

[0068] Based on the number of pulleys in the boom pulley block and hook pulley block, and the required lifting capacity, we first assume a multiplier n1, where n1 ≤ n max1 The lifting ratio n is assumed to be the lifting capacity to be achieved. Q Not less than the ratio of lifting capacity to maximum single-rope tension, i.e., n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; therefore, it is assumed that the range of values ​​for n1 is nQmin ≤n1≤n Hmax Where Q is the maximum load under the boom pulley block when the load is lifted off the ground, and n Q The lifting ratio is the maximum load under the boom pulley block when the load is lifted off the ground.

[0069] Calculate the efficiency η of the pulley system with the assumed n1 ratio. Z1 :

[0070] η Z1 =η D (1-η n1 ) / [n1×(1-η)] (1)

[0071] Where η is the efficiency of a single pulley, and D is the number of guide pulleys between the boom pulley block and the winch;

[0072] Calculate the single-rope tension T1 of the hoisting wire rope at the n1 ratio:

[0073] T1=Q / (n1η Z1 (2)

[0074] If T1 > T max Then, assume the multiplier is n2, n2 = n1 + 1, and use equation (1) to calculate T2 by changing n1 to n2 and T1 to T2 in equations (1) and (2); if T2 > T max Let n3 = n1 + 2, calculate T3, and so on, until T... x ≤T max ; the corresponding n at this time x Then it is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n x ;

[0075] If T1 = T max Then n1 is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n1;

[0076] If T1 < T max Then, assume the multiplier is n2, n2 = n1 - 1, change n1 to n2 in equations (1) and (2), change T1 to T2, and calculate T2; if T2 < T max Let n3 = n1 - 2, calculate T3, and so on, until n x When the multiplier is T x ≥T max If T x >T max Then the corresponding (n x +1) is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =nx +1; if T x =T max Then the corresponding n x The lifting ratio, n, is determined as the lifting capacity. min2 =n x .

[0077] Among them, n in condition 3) min3 n max3 The method for determining it is as follows:

[0078] Calculate the maximum allowable remaining length L of the hoisting wire rope Ymax Determine the maximum allowable number of remaining layers i of the hoisting wire rope based on the structure of the hoist. max Maximum permissible remaining length L of the hoisting wire rope Ymax =L J1 +L J2 +…+L Ji ; where L J1 L is the length of the wire rope that can be wound in the first layer (i.e., the bottom layer) of the hoist; J2 The length of wire rope that can be wound in the second layer (i.e., the second bottom layer) of the winch is L. Ji The length of the wire rope that can be wound around the i-th layer of the winch is L. Ji ;

[0079] Calculate the minimum length L of the wire rope required to pull out the winch when the load is off the ground. Cmin :L Cmin =L S -L ymax ; where L S This refers to the length of the lifting wire rope;

[0080] Calculate the minimum lifting ratio n min3 :

[0081] L Cmin =L JD +L DB +n Smin *π*R B / 2+n Smin *π*R G / 2+n Smin *H;

[0082] n Smin =(L Cmin -L JD -L DB ) / (π*R B / 2+π*R G / 2+H);

[0083] n Smin If the calculated value is a decimal, round it up. The rounded value n SminThat is, n min3 ;where R B R is the diameter of the pulley in the boom pulley block. G Where L is the diameter of the hook pulley block, H is the distance between the center line of the boom pulley block and the center line of the hook pulley block when the load is lifted off the ground, and L is the diameter of the hook pulley block. JD L is the center distance from the winch to the guide pulley. DB The center distance between the guide pulley and the boom pulley block;

[0084] Calculate the maximum lifting ratio n max3 :

[0085] Let L Ymin =0, then L Cmax =L S ;

[0086] L S =L JD +L DB +n Smax *π*R B / 2+n Tmax *π*R G / 2+n Tmax *H;

[0087] n Smax =(L S -L JD -L DB ) / (π*R B / 2+π*R G / 2+H);

[0088] n Smax If the calculated value is a decimal, round it down. The rounded value n Smax That is, n max3 .

[0089] In the case of multiple winches lifting together, the present invention calculates each winch separately.

[0090] This invention describes how to determine the lifting ratio of a crane to ensure that the wire rope tension is not overloaded and that the winch does not become tangled without pre-tensioning the remaining wire rope. This ensures that the lifting system is not overloaded, the rope does not become tangled, and work efficiency is improved.

Claims

1. A method for determining the lifting wire rope ratio of a crane, characterized in that: The following conditions must be met simultaneously: 1) The lifting ratio n shall not exceed the maximum lifting ratio n determined by the number of pulleys in the boom pulley block and hook pulley block. max1 That is, n≤n max1 ; 2) The single rope tension T shall not exceed the maximum single rope tension T that the winch can provide. max The corresponding multiplier is the minimum multiplier n determined by the maximum single rope tension. min2 That is, T≤T max , n≥n min2 The lifting ratio shall not be less than the maximum single-rope tension T of the wire rope. max Lifting ratio at that time; 3) Number of remaining layers of hoisting wire rope (m) S Not greater than the maximum allowable number of remaining layers of the hoisting wire rope (m) Smax And it cannot be less than 0, m Smax The minimum magnification n is determined by the number of remaining layers of the hoisting wire rope. min3 m Smin The maximum multiplier n is determined by the minimum allowable number of remaining layers of the hoisting wire rope. max3 , i.e. m S ≤m Smax And m S ≥m Smin =0, n min3 ≤n≤n max3 The lifting ratio shall not be greater than the lifting ratio of the minimum allowable remaining number of layers of the winch wire rope and shall not be less than the lifting ratio of the maximum allowable remaining number of layers of the winch wire rope. 4) Considering conditions 1), 2), and 3), the method for determining the hoisting wire rope ratio n is MAX[n]. min2 n min3 ] ≤n≤MIN[n max1 n max3 ].

2. The method for determining the lifting wire rope ratio of a crane according to claim 1, characterized in that: In condition 1), n max1 The method for determining it is as follows: 1) If the number of pulleys in the boom pulley block is less than or equal to the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It is equal to twice the minimum number of pulleys in the boom pulley block or hook pulley block, i.e., n max1 =n Hmax =2×z B =2×z G Therefore, n≤n max1 =n Hmax That is, n≤2×z B =2×z G ; 2) If the number of pulleys in the boom pulley block is greater than the number of pulleys in the hook pulley block, the maximum lifting ratio n is determined by the number of pulleys. max1 It equals twice the minimum number of pulleys in the hook pulley system plus 1, i.e., n max1 =n Hmax =2×z G +1, therefore n≤n max1 =n Hmax That is, n≤2×z G +1; Where n H The lifting ratio, z, is determined by the number of pulleys in the boom pulley block and the hook pulley block. B z is the number of pulleys in the boom pulley system. G This refers to the number of pulleys in the hook pulley block.

3. The method for determining the lifting wire rope ratio of a crane according to claim 1, characterized in that: In condition 2), n min2 The method for determining it is as follows: Based on the number of pulleys in the boom pulley block and hook pulley block, and the required lifting capacity, we first assume a multiplier n1, where n1 ≤ n max1 The lifting ratio n is assumed to be the lifting capacity to be achieved. Q Not less than the ratio of lifting capacity to maximum single-rope tension, i.e., n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; therefore, it is assumed that the range of values ​​for n1 is n Qmin ≤n1≤n Hmax Where Q is the maximum load under the boom pulley block when the load is lifted off the ground, and n Q The lifting ratio is the maximum load under the boom pulley block when the load is lifted off the ground. Calculate the efficiency η of the pulley system with the assumed n1 ratio. Z1 : or Z1 =h D (1st) n1 ) / [n1×(1-n)] (1) Where η is the efficiency of a single pulley, and D is the number of guide pulleys between the boom pulley block and the winch; Calculate the single-rope tension T1 of the hoisting wire rope at the n1 ratio: T1=Q / (n1η Z1 ) (2) If T1 > T max Then, assume the multiplier is n2, n2 = n1 + 1, and use equation (1) to calculate T2 by changing n1 to n2 and T1 to T2 in equations (1) and (2); if T2 > T max Let n3 = n1 + 2, calculate T3, and so on, until T... x ≤T max ; the corresponding n at this time x Then it is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n x ; If T1=T max Then n1 is determined as the minimum lifting ratio for that lifting capacity, i.e., n min2 =n1; If T1 < T max Then, assume the multiplier is n2, n2 = n1 - 1, change n1 in equations (1) and (2) to n2, change T1 to T2, and calculate T2; if T2 < T max Let n3 = n1 - 2, calculate T3, and so on, until n x When the multiplier is T x ≥T max If T x >T max Then the corresponding (n) x +1) Determine the minimum lifting ratio for this lifting capacity, i.e., n min2 =n x +1; if T x =T max Then the corresponding n x The lifting ratio, n, is determined as the lifting capacity. min2 =n x .

4. The method for determining the lifting wire rope ratio of a crane according to claim 1, characterized in that: In condition 3), n min3 n max3 The method for determining it is as follows: Calculate the maximum allowable remaining length L of the hoisting wire rope Ymax The maximum allowable number of remaining layers (m) of the hoisting wire rope is determined based on the structure of the hoist. Smax Maximum permissible remaining length L of the hoisting wire rope Ymax =L J1 +L J2 +…+L Ji ; where L J1 This refers to the first layer of the winch, which is the bottom layer, and the length of the wire rope that can be wound around it; L J2 The second layer of the winch, which is the sub-bottom layer, has a wire rope length of L that can be wound around it. Ji The length of the wire rope that can be wound around the i-th layer of the winch is L. Ji ; Calculate the minimum length L of the wire rope required to pull out the winch when the load is off the ground. Cmin :L Cmin =L S -L ymax ; where L S This refers to the length of the lifting wire rope; Calculate the minimum lifting ratio n min3 : L Cmin =L JD +L DB +n Smin ×π×R B / 2+n Smin ×π×R G / 2+n Smin ×H; n Smin =(L Cmin -L JD -L DB ) / (π×R B / 2+π×R G / 2+H); n Smin If the calculated value is a decimal, round it up. The rounded value n Smin That is, n min3 ;where R B R is the diameter of the pulley in the boom pulley block. G Where L is the diameter of the hook pulley block, H is the distance between the center line of the boom pulley block and the center line of the hook pulley block when the load is lifted off the ground, and L is the diameter of the hook pulley block. JD L is the center distance from the winch to the guide pulley. DB The center distance between the guide pulley and the boom pulley block; Calculate the maximum lifting ratio n max3 : Let L Ymin =0, then L Cmax =L S ; L S =L JD +L DB +n Smax ×π×R B / 2+n Tmax ×π×R G / 2+n Tmax ×H; n Smax =(L S -L JD -L DB ) / (π×R B / 2+π×R G / 2+H); n Smax If the calculated value is a decimal, round it down. The rounded value n Smax That is, n max3 .

5. The method for determining the lifting wire rope ratio of a crane according to any one of claims 1-4, characterized in that: For cases where multiple winches are used for joint lifting, each winch is calculated separately.

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