Method for determining multiplying power of hoisting steel wire rope of crane

Abstract

The invention discloses a method for determining the multiplying power of a hoisting steel wire rope of a crane. The method comprises the following steps: 1) the hoisting multiplying power is not greater than the maximum hoisting multiplying power nmax1 determined by the number of pulleys of a boom pulley block and a hook pulley block; (2) the single-rope tension is not larger than the maximum single-rope tension Tmax of the steel wire rope provided by hoisting, the corresponding multiplying power is the minimum multiplying power nmin2 determined by the maximum single-rope tension, and the lifting multiplying power is not smaller than the lifting multiplying power when the maximum single-rope tension Tmax of the steel wire rope; (3) the residual layer number of the hoisting steel wire rope is not larger than the maximum allowable residual layer number of the hoisting steel wire rope and cannot be smaller than 0, mSmax corresponds to the minimum multiplying power nmin3 determined by the residual layer number of the hoisting steel wire rope, and mSmin corresponds to the maximum multiplying power nmax3 determined by the residual layer number of the hoisting steel wire rope; the lifting multiplying power is not larger than the lifting multiplying power of the minimum allowable remaining layer number of the hoisting steel wire rope and is not smaller than the lifting multiplying power of the maximum allowable remaining layer number of the hoisting steel wire rope; and 4) according to the conditions 1), 2) and 3), the method for determining the multiplying power n of the hoisting steel wire rope is that n is greater than or equal to MAX [nmin2, nmin3] and less than or equal to MIN [nmax1, nmax3].

Description

Technical Field

[0001] The invention relates to the field of cranes, and in particular to a method for determining the multiple of a hoisting wire rope of a crane. Background Art

[0002] Crane: A machine used to lift and move heavy objects. Boom: A component of a crane located between the main engine and the hook, used to support the load. Winch: A mechanism on a crane used to wind up the 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: A device on a crane consisting of more than one pulley that achieves a larger pulling force with a smaller single rope pulling force.

[0003] The lifting system of a crane usually consists of a winch, wire ropes, a boom pulley block and a hook.

[0004] When the lifting weight is small, a single winch is generally used for lifting. The winch is wrapped with a wire rope, which passes through a guide pulley and is wound between the boom pulley block and the hook pulley block through a set winding method. The hook can carry heavy objects. The winch is rotated to retract and release the wire rope, and the distance between the boom pulley block and the hook is changed to achieve the action of lifting and lowering the heavy object.

[0005] When the lifting weight is large, double or multiple winches are often used for lifting. Each winch is wrapped with a wire rope, which passes through a guide pulley and is wound between the pulley block on one side of the boom and the pulley block on one side of the hook through a set winding method; the winch is wrapped with a wire rope, which passes through a guide pulley and is wound between the pulley block on the other side of the boom and the pulley block on the other side of the hook through a set winding method; the hook and the two pulley blocks are connected to the same hook head to form 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 6-multiplier. 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 2×6 ratio, where 2 is 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 method usually adopted is to increase the number of lifting wire ropes wound between the boom pulley block and the hook pulley block, that is, to increase the multiplier.

[0008] The commonly used method to determine the magnification is:

[0009] 1. According to the number of pulleys in the arm pulley block and the hook pulley block and the required lifting weight, assume a ratio n1 and calculate the pulley efficiency η of the ratio Z1 :

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

[0011] Where 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 lifting wire rope at this ratio:

[0013] T1=Q / (n1η Z1 ) (2)

[0014] Where Q is the maximum load under the boom pulley block.

[0015] If T1>T max , then set the assumed magnification to n2, n2 = n1 + 1, change n1 in equation (1) and equation (2) to n2, and calculate T2. If T2 > T max , then let n2=n1+2, calculate T2 until T2≤T max At this time, the corresponding n2 is determined as the lifting ratio of the lifting weight.

[0016] If T1 = T max , then n1 is determined as the lifting ratio of the lifting weight.

[0017] If T1<T max , then set the assumed magnification to n2, n2 = n1-1, change n1 in equation (1) and equation (2) to n2, and calculate T2. max , then let n2=n1-2, calculate T2 until T2≥T max If T2>T max , then the corresponding n2+1 is determined as the lifting ratio of the lifting weight; if T2=T max , then the corresponding n2 is determined as the lifting ratio of the lifting weight.

[0018] However, the existing technology mainly considers the lifting capacity determined by the single rope tension and the lifting ratio to ensure that the winch is not overloaded, and the premise is that when the hook reaches the position of the hoisted object, the remaining wire rope in the winch is in a pre-tightened state. However, it does not consider the number of layers of remaining wire rope in the winch when the hook reaches the position of the hoisted object. If the number of layers of remaining wire rope in the winch is large and the remaining wire rope is not pre-tightened, the remaining wire rope is in a loose state. When lifting, the wire rope wound into the winch is in a taut state and will fall into the loose remaining wire rope, causing the winch wire rope to be irregularly wound, and the wire rope will be damaged or even broken, causing an accident. The pre-tightening of the remaining wire rope is time-consuming and labor-intensive, and crane users are generally unwilling to pre-tighten it before each lifting, and even basically do not pre-tighten it.

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

[0020] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a method for determining the ratio of the hoisting wire rope of a crane. By reasonably determining the hoisting ratio, irregular winding of the hoisting wire rope is avoided, and there is no need to pre-tighten the remaining hoisting wire rope, thereby ensuring that the single-rope tension of the wire rope does not exceed its maximum single-rope tension, and the number of remaining hoisting wire rope layers does not exceed the safe number of layers, thereby preventing irregular winding of the hoisting wire rope and ensuring lifting safety.

[0021] Technical solution: A method for determining the ratio of a crane hoisting wire rope of the present invention is characterized in that the following conditions are met at the same time:

[0022] 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 , that is, n≤n max1 ;

[0023] 2) The single rope tension is not greater than the maximum single rope tension T of the wire rope that the winch can provide max The corresponding magnification is the minimum magnification n determined by the maximum single rope tension min2 , that is, T≤T max , n≥n min2 , the lifting ratio is not less than the maximum single rope tension of the wire rope T max The lifting ratio at 10 ...

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

[0025] 4) Comprehensive 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 ].

[0026] Among them, in the condition 1), n max1 The method to determine is:

[0027] 1) If the number of pulleys in the arm 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 Equal to twice the minimum number of pulleys in the arm pulley block or hook pulley block, that is, n max1 =n Hmax =2*z B =2*z G , so n≤n max1 =n Hmax , that is, n≤22*z B =2*z G ;

[0028] 2) If the number of pulleys in the arm 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 is equal to twice the minimum number of pulleys in the hook pulley block + 1, that is, n max1 =n Hmax =2*z G +1, so n≤n max1 =n Hmax , that is, n≤2*z G +1;

[0029] where n H The lifting ratio is determined by the number of pulleys in the arm pulley block and the hook pulley block, z B is the number of pulleys in the arm pulley assembly, z G is the number of pulleys in the hook pulley block.

[0030] Among them, in the condition 2), n min2 The method to determine is:

[0031] According to the number of pulleys in the arm pulley block and the hook pulley block and the required lifting capacity, first assume a ratio n1, n1≤n max1 ; The lifting factor n assumed according to the lifting capacity required Q Not less than the ratio of the lifting weight to the maximum single rope tension, that is, n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; then it is assumed that the value range of n1 is n Qmin ≤n1≤n Hmax ; Q is the maximum load under the boom pulley block when the weight is lifted off the ground, n Q It is the lifting ratio at the maximum load under the boom pulley block when the heavy object is lifted off the ground;

[0032] Calculate the pulley efficiency η for 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 lifting wire rope at the n1 ratio:

[0036] T1=Q / (n1η Z1 ) (2)

[0037] If T1>T max , then set the assumed magnification to n2, n2 = n1 + 1, and use formula (1) to calculate. Change n1 in formula (1) and formula (2) to n2, and T1 to T2, and calculate T2; if T2>T max , then 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 of the lifting weight, that is, n min2 =n x ;

[0038] If T1 = T max , then n1 is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =n1;

[0039] If T1<T max, then set the assumed magnification to n2, n2 = n1-1, change n1 in equation (1) and equation (2) to n2, change T1 to T2, and calculate T2; if T2 < T max , then let n3 = n1-2, calculate T3, and so on, until n x Ratio T x ≥T max ; if T x >T max , then the corresponding (n x +1) is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =n x +1; if T x =T max , then the corresponding n x Determine the lifting ratio of the lifting weight, that is, n min2 =n x .

[0040] Among them, in the condition 3), n min3 、n max3 The method to determine is:

[0041] Calculate the maximum allowable remaining length L of the winch wire rope Ymax :Determine the maximum allowable remaining layers of winch wire rope i according to the winch structure max , the maximum allowable remaining length of the winch wire rope L Ymax =L J1 +L J2 +…+L Ji ; where L J1 L is the length of wire rope that can be wound on the first layer (i.e. the bottom layer) of the winch; J2 The length of the wire rope that can be wound on 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 for the i-th layer of winch is L Ji ;

[0042] Calculate the minimum length L of the wire rope to be pulled out of the winch when the heavy object is off the ground Cmin :L Cmin =L S -L ymax ; where L S is 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, it will be rounded up. Smin That is n min3 ; where R B is the pulley diameter of the boom pulley block, R G is the pulley 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 weight is lifted off the ground, and L JD L is the center distance from winch to guide pulley. DB The center distance from the guide pulley to 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, it will be rounded down. The rounded n Smax That is n max3 .

[0052] In the case of combined lifting with multiple winches, each winch is calculated separately.

[0053] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention introduces how to determine the hoisting ratio of the crane to ensure that the wire rope tension is not overloaded, and the hoisting can be ensured not to be tangled without pre-tightening the remaining wire rope of the hoisting. It can ensure that the hoisting system is not overloaded, the rope is not tangled, and the operating efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the structure of a single-roll hoist;

[0055] Figure 2 It is a schematic diagram of the structure of double hoisting;

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

[0057] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0058] The method for determining the crane hoisting wire rope multiplier of the present invention is characterized in that the following conditions are met at the same time:

[0059] 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 , that is, n≤n max1 ;

[0060] 2) The single rope tension is not greater than the maximum single rope tension T of the wire rope that the winch can provide max The corresponding magnification is the minimum magnification n determined by the maximum single rope tension min2 , that is, T≤T max , n≥n min2 , the lifting ratio is not less than the maximum single rope tension of the wire rope T max The lifting ratio at 10 ...

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

[0062] 4) Comprehensive 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 ].

[0063] Among them, n in condition 1) max1 The method to determine is:

[0064] 1) If the number of pulleys in the arm 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 Equal to twice the minimum number of pulleys in the arm pulley block or hook pulley block, that is, n max1 =n Hmax =2*z B =2*z G , so n≤n max1 =n Hmax , that is, n≤22*z B =2*z G ;

[0065] 2) If the number of pulleys in the arm 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 is equal to twice the minimum number of pulleys in the hook pulley block + 1, that is, n max1 =n Hmax =2*z G +1, so n≤n max1 =n Hmax , that is, n≤2*z G +1;

[0066] where n H The lifting ratio is determined by the number of pulleys in the arm pulley block and the hook pulley block, z B is the number of pulleys in the arm pulley assembly, z G is the number of pulleys in the hook pulley block.

[0067] Among them, n in condition 2) min2 The method to determine is:

[0068] According to the number of pulleys in the arm pulley block and the hook pulley block and the required lifting capacity, first assume a ratio n1, n1≤n max1 ; The lifting factor n assumed according to the lifting capacity required Q Not less than the ratio of the lifting weight to the maximum single rope tension, that is, n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; then it is assumed that the value range of n1 is nQmin ≤n1≤n Hmax ; Q is the maximum load under the boom pulley block when the weight is lifted off the ground, n Q It is the lifting ratio at the maximum load under the boom pulley block when the heavy object is lifted off the ground;

[0069] Calculate the pulley efficiency η for 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 lifting wire rope at the n1 ratio:

[0073] T1=Q / (n1η Z1 ) (2)

[0074] If T1>T max , then set the assumed magnification to n2, n2 = n1 + 1, and use formula (1) to calculate. Change n1 in formula (1) and formula (2) to n2, and T1 to T2, and calculate T2; if T2>T max , then 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 of the lifting weight, that is, n min2 =n x ;

[0075] If T1 = T max , then n1 is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =n1;

[0076] If T1<T max , then set the assumed magnification to n2, n2 = n1-1, change n1 in equation (1) and equation (2) to n2, change T1 to T2, and calculate T2; if T2 < T max , then let n3 = n1-2, calculate T3, and so on, until n x Ratio T x ≥T max ; if T x >T max , then the corresponding (n x +1) is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =nx +1; if T x =T max , then the corresponding n x Determine the lifting ratio of the lifting weight, that is, n min2 =n x .

[0077] Among them, n in condition 3) min3 、n max3 The method to determine is:

[0078] Calculate the maximum allowable remaining length L of the winch wire rope Ymax :Determine the maximum allowable remaining layers of winch wire rope i according to the winch structure max , the maximum allowable remaining length of the winch wire rope L Ymax =L J1 +L J2 +…+L Ji ; where L J1 L is the length of wire rope that can be wound on the first layer (i.e. the bottom layer) of the winch; J2 The length of the wire rope that can be wound on 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 for the i-th layer of winch is L Ji ;

[0079] Calculate the minimum length L of the wire rope to be pulled out of the winch when the heavy object is off the ground Cmin :L Cmin =L S -L ymax ; where L S is 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, it will be rounded up. SminThat is n min3 ; where R B is the pulley diameter of the boom pulley block, R G is the pulley 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 weight is lifted off the ground, and L JD L is the center distance from winch to guide pulley. DB The center distance from the guide pulley to 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, it will be rounded down. The rounded n Smax That is n max3 .

[0089] In the present invention, in the case of joint lifting of multiple winches, each winch is calculated separately.

[0090] The invention introduces how to determine the hoisting ratio of a crane to ensure that the wire rope tension is not overloaded and the winch does not need to be pre-tightened to ensure that the winch does not become tangled. The invention can ensure that the hoisting system does not become overloaded or tangled and improve the operation efficiency.

Claims

1. A method for determining the ratio of a crane hoisting wire rope, characterized in that: The following conditions must be met at the same time: 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 , that is, n≤n max1 ; 2) The single rope tension is not greater than the maximum single rope tension T of the wire rope that the winch can provide max The corresponding magnification is the minimum magnification n determined by the maximum single rope tension min2 , that is, T≤T max , n≥n min2 , the lifting ratio is not less than the maximum single rope tension of the wire rope T max The lifting ratio at 10 ... 3) The remaining number of layers of hoisting wire rope shall not be greater than the maximum allowable remaining number of layers of hoisting wire rope and shall not be less than 0, m Smax The minimum ratio n is determined by the number of remaining layers of the corresponding hoisting wire rope min3 , m Smin The maximum ratio n is determined by the number of remaining layers of the corresponding hoisting wire rope max3 , that is, m S ≤m Smax And m S ≥m Smin =0,n min3 ≤n≤n 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 the lifting ratio is not less than the lifting ratio of the maximum allowable remaining number of layers of the hoisting wire rope; 4) Comprehensive 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 ].

2. The method for determining the crane hoisting wire rope ratio according to claim 1, characterized in that: In the condition 1) described above, n max1 The method to determine is: 1) If the number of pulleys in the arm 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 Equal to twice the minimum number of pulleys in the arm pulley block or hook pulley block, that is, n max1 =n Hmax =2*z B =2*z G , so n≤n max1 =n Hmax , that is, n≤22*z B =2*z G ; 2) If the number of pulleys in the arm 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 is equal to twice the minimum number of pulleys in the hook pulley block + 1, that is, n max1 =n Hmax =2*z G +1, so n≤n max1 =n Hmax , that is, n≤2*z G +1; where n H The lifting ratio is determined by the number of pulleys in the arm pulley block and the hook pulley block, z B is the number of pulleys in the arm pulley assembly, z G is the number of pulleys in the hook pulley block.

3. The method for determining the crane hoisting wire rope ratio according to claim 1, characterized in that: In the condition 2) described above, n min2 The method to determine is: According to the number of pulleys in the arm pulley block and the hook pulley block and the required lifting capacity, first assume a ratio n1, n1≤n max1 ; The lifting factor n assumed according to the lifting capacity required Q Not less than the ratio of the lifting weight to the maximum single rope tension, that is, n Qmin ≥Q / T max , if Q / T max If the calculated value is a decimal, it is rounded up; then it is assumed that the value range of n1 is n Qmin ≤n1≤n Hmax ; Q is the maximum load under the boom pulley block when the weight is lifted off the ground, n Q It is the lifting ratio at the maximum load under the boom pulley block when the heavy object is lifted off the ground; Calculate the pulley efficiency η for the assumed n1 ratio Z1 : or Z1 =the 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 lifting wire rope at the n1 ratio: T1=Q / (n1η Z1 ) (2) If T1>T max , then set the assumed magnification to n2, n2 = n1 + 1, and use formula (1) to calculate. Change n1 in formula (1) and formula (2) to n2, and T1 to T2, and calculate T2; if T2>T max , then 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 of the lifting weight, that is, n min2 =n x ; If T1 = T max , then n1 is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =n1; If T1<T max , then set the assumed magnification to n2, n2 = n1-1, change n1 in equation (1) and equation (2) to n2, change T1 to T2, and calculate T2; if T2 < T max , then let n3 = n1-2, calculate T3, and so on, until n x Ratio T x ≥T max ; if T x >T max , then the corresponding (n x +1) is determined as the minimum lifting ratio of the lifting weight, that is, n min2 =n x +1; if T x =T max , then the corresponding n x Determine the lifting ratio of the lifting weight, that is, n min2 =n x .

4. The method for determining the crane hoisting wire rope ratio according to claim 1, characterized in that: In the condition 3) described above, n min3 、n max3 The method to determine is: Calculate the maximum allowable remaining length L of the winch wire rope Ymax :Determine the maximum allowable remaining layers of winch wire rope i according to the winch structure max , the maximum allowable remaining length of the winch wire rope L Ymax =L J1 +L J2 +…+L Ji ; where L J1 L is the length of wire rope that can be wound on the first layer (i.e. the bottom layer) of the winch; J2 The length of the wire rope that can be wound on 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 for the i-th layer of winch is L Ji ; Calculate the minimum length L of the wire rope to be pulled out of the winch when the heavy object is off the ground Cmin :L Cmin =L S -L ymax ; where L S is the length of the lifting wire rope; Calculate the minimum lifting ratio n min3 : L Cmin =L JD +L DB +n Smin *p*R B / 2+n Smin *p*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, it will be rounded up. Smin That is n min3 ; where R B is the pulley diameter of the boom pulley block, R G is the pulley 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 weight is lifted off the ground, and L JD L is the center distance from winch to guide pulley. DB The center distance from the guide pulley to 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 *p*R B / 2+n Tmax *p*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, it will be rounded down. The rounded n Smax That is n max3 .

5. The method for determining the crane hoisting wire rope ratio according to any one of claims 1 to 4, characterized in that: In the case of combined lifting with multiple winches, each winch is calculated separately.

Images