Assembling method and disassembling method of floor double-rocker-arm derrick

Abstract

The invention relates to the technical field of lifting appliances, in particular to an assembling method and a disassembling method of a floor double-rocker-arm derrick, according to the assembling method, firstly, geological conditions of different sites are considered, and the stability and the flatness of a fixed base are ensured through different foundation treatment modes; the step effectively prevents the rod body assembly from sinking or inclining, the stability and safety of the equipment are improved, and the lifting height of the double-rocker-arm derrick can be correspondingly increased along with the increase of the height of the rod body assembly. The method is flexible and efficient and can meet the requirements of operation at different heights by dismantling connecting bolts, hoisting a rod body and utilizing a hanging bracket and a roller lifting assembly on the jacking sleeve frame to carry out mechanical lifting; in the dismounting process, the lifting hook of the rocker arm assembly is firstly lowered to the ground and is dismounted, the risk of high-altitude hanging objects is reduced, and therefore the safety of the dismounting process is improved, all the components can be completely dismounted through an ordered dismounting method, and follow-up repair, maintenance and reutilization are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of lifting equipment, and in particular to an assembly method and a disassembly method of a ground-mounted double rocker arm holding rod. Background Art

[0002] With the development of power transmission grid construction, the number of interconnection projects is increasing, so the number of power towers is increasing. The construction of power towers requires the use of lifting equipment such as power poles. In the past, in the construction process in remote mountainous areas, while ensuring the safety of lifting equipment, remote mountainous areas gradually developed in the direction of miniaturization and automation, and the use of light and small double-jib poles became more and more extensive. In the field of infrastructure construction, especially in the power and communications industries, ground-mounted double-jib poles, as an important construction equipment, play a pivotal role. However, with the continuous advancement of technology and the increasing requirements of construction, traditional ground-mounted double-jib poles have gradually exposed some problems, such as large footprint, heavy weight, high price, and large assembly and disassembly workload; these problems not only affect construction efficiency, but also increase construction costs, and even pose a certain threat to construction safety.

[0003] The main action process of the traditional floor-standing double rocker arm is mostly realized by motorized capstan when meeting the work needs. For example, the ups and downs and lifting process of the arm are realized by an independent motorized capstan, and the rotation of the arm is directly completed by manpower. It has low safety performance and extremely high requirements for the synchronization of operations. When assembling the jacking device, it is often difficult for large hydraulic equipment to enter the site due to the mountainous terrain and the heavy weight of large hydraulic equipment. Summary of the invention

[0004] In order to solve some problems existing in the above-mentioned prior art, the present invention provides an assembly method and a disassembly method of a ground-mounted double rocker arm holding rod to solve the deficiencies existing in the prior art.

[0005] To achieve the above object, the present invention provides an assembly method for a floor-standing double rocker arm, the assembly method comprising the following steps:

[0006] Step 1: Install the fixed base; ensure that the fixed base is flat and compacted. To prevent the rod assembly from sinking or tilting, dig the site and level the site.

[0007] When the site is made of hard soil, loose gravel, mudstone, sandstone or other relatively hard soil, level the site and lay a layer of gravel on it, and then place the fixed base on the site;

[0008] When the site is relatively soft soil such as ordinary soil or clay soil, foundation treatment is required. The site endurance value must be greater than or equal to 150kPa, and then road timber or steel is used on the site;

[0009] Step 2: Install the base cable and tighten it, and ensure that the load of the corresponding tool is not less than 50kN. Adjust the base cable on one side of the lower part of the fixed base to the same height as the cable on the opposite side;

[0010] Step 3: Install the jacking frame on the fixed base while paying attention to the opening direction and the pulling direction, arrange the position of the hydraulic operating table reasonably, and install the pull wire and other components in time; after the main structure of the jacking frame is installed, install the remaining structure of the jacking frame;

[0011] Step 4: Install the rocker arm assembly; the rocker arm assembly must be arranged symmetrically along the line or the horizontal line and on both sides of the opening direction of the lifting frame. Use the top of the mast assembly to hoist the rocker arm assembly to the slewing connection, install the pin shaft, and check the connection of each component;

[0012] Step 5: After the assembly is completed, the pole should be inspected to check whether the supporting tools are operating normally and whether the fastening connection between the components is in good condition; check whether the wire rope is threaded correctly and whether there is any interference; check whether there is any debris on the pole. After the pole is assembled, no-load test and load test should be carried out in turn; hoist the pole at the maximum amplitude to 25%, 50%, 75%, and 100% of the rated lifting weight respectively, and test according to the requirements of the fastening connection between the components;

[0013] Step 6: During use, as the height of the pole assembly is continuously increased, the lifting height of the double rocker arm boom also needs to be continuously increased. Remove the bolts connecting the pole body and the fixed base, hoist the pole body, use the hanger on the jacking sleeve to lift multiple groups of first standard sections and second standard sections on the pole body, use the roller lifting assembly on the jacking sleeve to perform mechanical lifting, and stop after the lifting exceeds the length of any group of first standard sections or second standard sections. Place any group of first standard sections or second standard sections into the jacking sleeve, slightly lower the lifted part, install the connecting bolts, and repeat the jacking and heightening operation until the installation is completed, and then lock it with the tower body with bolts;

[0014] Step 7: Install the waist ring; hoist one waist ring half frame with rollers installed to the desired derrick installation position, hoist the other waist ring half frame with rollers installed to the first waist ring half frame and connect them together. Do not tighten them at this time, adjust the upper and lower positions of the waist ring, install the pull rope and anti-sinking pull line, so that the rollers in all directions of the waist ring can support the rod assembly, and lock them after the waist ring position is determined.

[0015] A beneficial effect of the present invention is:

[0016] 1. Strong site adaptability: The assembly method first takes into account the geological conditions of different sites, and ensures the stability and flatness of the fixed base through different foundation treatment methods; this step effectively prevents the sinking or tilting of the pole assembly and improves the stability and safety of the equipment.

[0017] 2. Guy wire adjustment ensures balance: By installing and tightening the base guy wires, especially adjusting the base guy wires on one side of the fixed base to the same height as the guy wires on the opposite side, the overall stability of the pole is further enhanced; this method helps to maintain the balance of the pole under the influence of complex terrain or external factors such as wind.

[0018] 3. Modular and symmetrical design: The installation of the lifting frame and rocker arm assembly embodies the idea of ​​modular design, which not only simplifies the installation process, but also makes the structure more compact and stable; at the same time, the rocker arm assembly is symmetrically arranged along the line or transverse line direction, which is conducive to maintaining mechanical balance and reducing stress concentration caused by eccentric load.

[0019] 4. Strict quality control: The inspection work after assembly is very detailed, including the operating condition of tools, the fastening and connection condition of each component, the threading and winding of the wire rope, and the cleaning of debris on the pole; these meticulous inspection steps help to timely discover and correct potential safety hazards and ensure the reliability of the pole during use.

[0020] 5. Flexible lifting mechanism: As the height of the pole assembly increases, the lifting height of the double rocker arm can also be increased accordingly; by removing the connecting bolts, hoisting the pole body and using the hanger and roller lifting assembly on the jacking frame for mechanical lifting, this method is both flexible and efficient and can meet the needs of operations at different heights.

[0021] 6. Waist ring enhances stability: The final step of installing the waist ring further enhances the overall stability of the pole; the waist ring is in close contact with the pole assembly through rollers and is fixed by pull ropes and anti-sinking wires, effectively preventing the pole from shaking or shifting during use.

[0022] The present invention also provides a method for disassembling a ground-mounted double rocker arm, the method comprising the following steps:

[0023] Step 1: Lower the hooks on the first rocker arm and the second rocker arm of the rocker arm assembly to the ground and place them firmly, and remove the hooks;

[0024] Step 2: After the hook is removed, the first rocker arm and the second rocker arm are lifted and lifted to both sides of the fixed mast of the mast assembly to fix them into a whole;

[0025] Step 3: Remove the rocker arm assembly, rotate the slewing bearing by ±45°, and remove the first standard section, second standard section, base section, mast assembly, lifting sleeve and other parts in turn, and finally remove the fixed base.

[0026] Another beneficial effect of the present invention is:

[0027] 1. Enhanced safety: The disassembly process first reduces the risk of high-altitude hanging objects by lowering the hook of the rocker arm assembly to the ground and removing it, thereby improving the safety of the disassembly process; in addition, the first rocker arm and the second rocker arm are lifted and fixed on both sides of the mast assembly to form a stable overall structure, which reduces the possibility of accidental falling off or shaking during subsequent disassembly operations.

[0028] 2. Improved orderliness and efficiency: The disassembly method follows a clear and orderly procedure, from the removal of the hook to the disassembly of each component. Each step has a clear purpose and sequence; this orderliness not only improves the efficiency of disassembly, but also reduces safety risks caused by chaotic operations.

[0029] 3. Consideration of structural protection: During the disassembly process, the slewing bearing is rotated ±45° and then each part is removed in turn. This practice helps to protect the structure from damage during the disassembly process; especially for some precise or vulnerable parts, such as the first standard section, the second standard section, etc., this method can ensure their safe and complete disassembly, which is convenient for subsequent storage and reuse.

[0030] 4. Resource conservation and environmental protection: The orderly disassembly method allows each component to be completely disassembled, which is convenient for subsequent repair, maintenance and reuse. This not only extends the service life of the equipment, but also reduces resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to facilitate the understanding of those skilled in the art, the present invention is further described below with reference to the accompanying drawings:

[0032] Figure 1 This is a verification diagram when the angle between the amplitude modulation pulley group and the rocker arm is 45° when the rocker arm is laid flat.

[0033] Figure 2 This is a schematic diagram showing the distribution of horizontal wind loads that the pole needs to bear in addition to the central pressure.

[0034] Figure 3 Schematic diagram of the strength verification of the rocker arm.

[0035] Figure 4 This is the force analysis diagram of the rocker arm main material.

[0036] Figure 5 Schematic diagram of the horizontal load distribution and support reaction of the boom.

[0037] Figure 6 This is the analysis diagram of the deadweight stress of the pole. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution in this application, Figure 1-6 The present invention is further described. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0039] like Figure 1-6 The assembly method of a ground-mounted double rocker arm holding rod shown in the figure comprises the following steps:

[0040] Step 1: Install the fixed base; ensure that the fixed base is flat and compacted. To prevent the rod assembly from sinking or tilting, dig the site and level the site.

[0041] When the site is made of hard soil, loose gravel, mudstone, sandstone or other relatively hard soil, level the site and lay a layer of gravel on it, and then place the fixed base on the site;

[0042] When the site is relatively soft soil such as ordinary soil or clay soil, foundation treatment is required. The site endurance value must be greater than or equal to 150kPa, and then road timber or steel is used on the site;

[0043] Step 2: Install the base cable and tighten it, and ensure that the load of the corresponding tool is not less than 50kN. Adjust the base cable on one side of the lower part of the fixed base to the same height as the cable on the opposite side;

[0044] Step 3: Install the jacking frame on the fixed base while paying attention to the opening direction and the pulling direction, arrange the position of the hydraulic operating table reasonably, and install the pull wire and other components in time; after the main structure of the jacking frame is installed, install the remaining structure of the jacking frame;

[0045] Step 4: Install the rocker arm assembly; the rocker arm assembly must be arranged symmetrically along the line or the horizontal line and on both sides of the opening direction of the lifting frame. Use the top of the mast assembly to hoist the rocker arm assembly to the slewing connection, install the pin shaft, and check the connection of each component;

[0046] Step 5: After the assembly is completed, the pole should be inspected to check whether the supporting tools are operating normally and whether the fastening connection between the components is in good condition; check whether the wire rope is threaded correctly and whether there is any interference; check whether there is any debris on the pole. After the pole is assembled, no-load test and load test should be carried out in turn; hoist the pole at the maximum amplitude to 25%, 50%, 75%, and 100% of the rated lifting weight respectively, and test according to the requirements of the fastening connection between the components;

[0047] Step 6: During use, as the height of the pole assembly is continuously increased, the lifting height of the double rocker arm boom also needs to be continuously increased. Remove the bolts connecting the pole body and the fixed base, hoist the pole body, use the hanger on the jacking sleeve to lift multiple groups of first standard sections and second standard sections on the pole body, use the roller lifting assembly on the jacking sleeve to perform mechanical lifting, and stop after the lifting exceeds the length of any group of first standard sections or second standard sections. Place any group of first standard sections or second standard sections into the jacking sleeve, slightly lower the lifted part, install the connecting bolts, and repeat the jacking and heightening operation until the installation is completed, and then lock it with the tower body with bolts;

[0048] Step 7: Install the waist ring; hoist one waist ring half frame with rollers installed to the desired derrick installation position, hoist the other waist ring half frame with rollers installed to the first waist ring half frame and connect them together. Do not tighten them at this time, adjust the upper and lower positions of the waist ring, install the pull rope and anti-sinking pull line, so that the rollers in all directions of the waist ring can support the rod assembly, and lock them after the waist ring position is determined.

[0049] A method for disassembling a ground-mounted double rocker arm, the method comprising the following steps:

[0050] Step 1: Lower the hooks on the first rocker arm and the second rocker arm of the rocker arm assembly to the ground and place them firmly, and remove the hooks;

[0051] Step 2: After the hook is removed, the first rocker arm and the second rocker arm are lifted and lifted to both sides of the fixed mast of the mast assembly to fix them into a whole;

[0052] Step 3: Remove the rocker arm assembly, rotate the slewing bearing by ±45°, and remove the first standard section, second standard section, base section, mast assembly, lifting sleeve and other parts in turn, and finally remove the fixed base.

[0053] When the present invention is working, before starting to assemble the ground-mounted double rocker arm, it is necessary to ensure that all necessary components are ready. These components include the mounting base, rod body assembly, jacking sleeve, rocker arm assembly, mast assembly, base section, waist ring and roller lifting assembly.

[0054] 1. Component inspection:

[0055] Carefully inspect each component to ensure it is intact and free of deformation, cracks, or other obvious damage.

[0056] Check whether all parts are complete, for example, small parts such as fixed pulley, luffing rope, safety rope, etc. should not be ignored; pay special attention to check whether rotating parts such as fixed pulley are flexible and can rotate freely.

[0057] 2. Placement and fixation of the installation base

[0058] Select the location: Select a site with a flat, solid and obstacle-free ground, which is the basis for ensuring the stability of the pole; perform necessary cleaning and leveling work on the site to ensure that there are no debris, gravel and other factors that may affect the stability of the base; Place and fix the base: Place the fixed base in the predetermined position, ensuring that its bottom is in full contact with the ground without hanging or tilting; Use the mounting plate and base cable to firmly fix and tighten the fixed base, which is an important step to prevent the base from moving or tilting during use.

[0059] 3. Assembly of the rod assembly and the lifting frame

[0060] Assembly of the pole body components: Connect multiple groups of first standard sections and second standard sections tightly in sequence to form a complete pole body; install angle plates on the pole body, which can significantly enhance the structural strength of the pole body and improve its load-bearing capacity and stability.

[0061] Place the rod assembly:

[0062] Place the assembled shaft vertically on the fixed base to ensure its verticality and stability; use tools such as a level to make fine adjustments to ensure that the shaft is not tilted.

[0063] Lifting frame assembly and installation:

[0064] Assemble the working platform, upper frame and lower frame together according to the design requirements to form a complete jacking frame structure; install necessary components such as lifting rings, hangers and upper pull wires on the jacking frame to ensure its complete functions and safety and reliability; fit the assembled jacking frame onto the outside of the rod assembly, paying attention to maintaining its smooth up and down sliding.

[0065] 4. Installation of rocker arm and mast assembly

[0066] Rocker arm assembly: Tightly connect the first rocker arm and the second rocker arm with the mounting base to form an integral rocker arm structure, and install fixed connecting ribs inside the rocker arm assembly. These connecting ribs can effectively improve the structural strength and rigidity of the rocker arm.

[0067] Installation of hook and slewing bearing: Install hooks on both sides of the rocker arm assembly. This is a key component for subsequent lifting operations and must be ensured to be firmly installed and function properly; connect the rocker arm assembly to the rod body assembly.

[0068] Assembly and installation of mast components: tightly connect the fixed mast and the mast body component together to form an integral mast structure; install the mast cap on the top of the fixed mast to enhance its structural integrity; install the first fixed bracket and the second fixed bracket in the middle section of the fixed mast, and perform precise assembly work through the pin shaft; in order to further enhance the structural strength, install several groups of fixed reinforcement ribs inside the first fixed bracket and the second fixed bracket.

[0069] 5. Installation of base section and roller lifting assembly

[0070] Assembly and installation of base sections: Connect multiple groups of transition sections tightly together to form a complete base section structure; install transition reinforcement ribs inside each transition section, which can significantly improve the structural strength and bearing capacity of the base section; install spacers between adjacent transition sections, which is an important measure to ensure the stability of the base section; install the assembled base section under the pole assembly to ensure that it can stably support the weight of the entire pole and various loads during the operation.

[0071] Installation of roller lifting assembly: Install multiple sets of fixed pulleys on both sides of the rod assembly and the mounting base to form a complete roller lifting assembly system; ensure that each fixed pulley can rotate freely and is firmly installed without shaking, which is the basic guarantee for the smooth progress of subsequent jacking and lifting operations.

[0072] The dangerous section of the ground-mounted four-jib boom is the upper waist ring of the boom, because at this section, the boom not only bears all the gravity of the part above the waist ring, but also bears the bending moment caused by wind loads, etc. When the boom is in use, the upper waist ring is located 10m below the boom. This calculation takes the reinforced section above the standard section for verification.

[0073] 1. Lifting pulley and traction rope

[0074] 1. Calculation conditions

[0075] (1) The maximum lifting weight is 1000 kg (10000 N), and the maximum deflection angle β of the lifting rope is 5°;

[0076] (2) The angle between the climbing rope and the ground is not greater than 45°, that is, ω = 45°;

[0077] (3) The lifting pulley group adopts a 1-go-1 pulley group, and the pulley efficiency value is η=0.95.

[0078] 2. Static tension T1 of the lifting pulley group

[0079] The static tension of the lifting block is

[0080]

[0081] Where G is the weight of the lifting component (hanging piece), N;

[0082] ω—Angle of the climbing rope to the ground;

[0083] β—the angle between the combined force line of the lifting pulley and the plumb bob;

[0084] Substituting the known conditions into the formula, we get

[0085]

[0086] Therefore, the lifting pulley selected is 20kN (single wheel).

[0087] 3. Static tension of traction rope T Q1

[0088] The lifting pulley group is 1-way and 1-way, and the 2 ropes are stressed.

[0089]

[0090] Where T Q1 —Tension of the traction rope, N;

[0091] n—number of ropes under load in the lifting block group;

[0092] η—efficiency of the pulley;

[0093]

[0094] T Q1P ≥6416×4.8=30797N

[0095] Therefore, Φ8 steel wire rope (6×19 type, σ b =1770MPa), T b =37.4kN>30.797kN, which meets the requirements. Each rope is 200m long and weighs about 48kg.

[0096] 4. Static tension F of climbing rope

[0097] The calculation formula is but

[0098]

[0099] F P ≥1355×4.8=6504N

[0100] Select Φ4 steel wire rope (6×19M type, σ b =1770MPa), T b =8.69kN>6.504kN, which meets the requirements. Each rope is 70m long and weighs about 4kg.

[0101] 2. Modulation pulley block and traction rope

[0102] 1. Calculation conditions

[0103] (1) Assume that the arm is 4 m long and the mast is 4 m long. When the arm is laid flat, the angle between the modulating block and the arm is 45°. Figure 1 as stated;

[0104] (2) The amplitude modulation pulley group adopts a 1-go-1 pulley group, with 2 ropes under force;

[0105] (3) According to calculations, when the rocker arm is laid flat, the amplitude modulation pulley group is subjected to the greatest force;

[0106] (4) The lifting weight at the end of the rocker arm is 10kN;

[0107] (5) The vertical load borne by the amplitude modulation rope is

[0108] 2. Static tension T2 of the amplitude modulation pulley group

[0109] like Figure 1 As shown, the static tension of the amplitude modulation pulley group is

[0110]

[0111] 3. Static tension T of the traction rope of the amplitude modulation pulley group Q2 for

[0112]

[0113] T Q2P ≥9.11×4.8=43.73kN

[0114] Choose Φ9 steel wire rope (6×19 type, σ b =1770MPa), T b =44kN>43.73kN, which meets the requirements. Each rope is 100m long and weighs about 28kg.

[0115] 3. Selection of insurance wire rope

[0116] Given T2, select the safety wire rope as follows:

[0117] T 2P ≥16.44×3=49.32kN

[0118] Select Φ10 steel wire rope (6×19 type, σ b =1770MPa), T b =54.3kN>49.32kN, which meets the requirements. Each rope is 5m long and weighs about 2kg.

[0119] 4. Calculation of wind load

[0120] 1. Wind load on the lifting rope

[0121] The horizontal load perpendicular to the lifting rope direction is

[0122]

[0123] Where W x ---Horizontal wind pressure per unit length perpendicular to the lifting rope direction, kN / m;

[0124] α---wind pressure unevenness coefficient, the value is 1.0;

[0125] μ Z --- Wind pressure height variation coefficient, the value is 1.49 (H = 70m);

[0126] μ SC ---Rope shape coefficient, the value is 1.2;

[0127] β C --- Wind load adjustment factor, the value is 1.0;

[0128] d---diameter of lifting wire rope, m;

[0129] v---wind speed at reference height, taken as 13m / s.

[0130] Substituting the known conditions into the formula, we get

[0131]

[0132] Each rope is 70m long and one rope is under force. Then the wind pressure of each set of lifting pulley rope is

[0133] P X1 =0.0015×70×1=0.105kN

[0134] 2. Wind load on luffing block rope

[0135] The length of the single-side amplitude modulation rope is 5.6 meters, two ropes are stressed, and the angle between the wind load and the amplitude modulation rope is 45°. According to the above method, the wind load on the single-side amplitude modulation rope is

[0136] P X2 =0.0017×5.6×2×sin45°=0.014kN

[0137] 3. Wind load on mast

[0138] The calculation formula of the wind load on the pole is: Where W S --- Wind load on the pole when the wind direction is perpendicular to the pole plane, kN / m;

[0139] υ---wind speed at reference height, value is 13m / s;

[0140] μ Z --- Wind pressure height variation coefficient, approximate value is 1.49 (H = 70m);

[0141] μ S ---Structural body coefficient, approximate value is 1.3×(1+η);

[0142] β Z --- Wind load adjustment factor, the approximate value is 1.8;

[0143] A f ---The projected area of ​​wind pressure borne by the pole with a length of 1m, m 2 .

[0144] The mast is a □400mm×400mm cross-section pole, the main material is ∠50mm×5mm, the diagonal material is ∠30mm×4mm, and the main flange material is ∠63mm×5mm. f =0.7799m 2 .

[0145] From the table, we get η=0.33

[0146] So μ S =1.3×(1+0.33)=1.72 9

[0147] Substituting the known conditions into the formula, we get

[0148]

[0149] 5. Calculation of the strength of the pole when both sides are hoisted with a load of 10kN

[0150] 1. Central pressure of the mast

[0151] (1) The vertical pressure caused by the tension of the amplitude modulation rope is

[0152] G F =(11.625+9.11)×2=41.47kN=41470N

[0153] (2) The mast’s deadweight is G V =2450N

[0154] (3) The central pressure of the mast is

[0155] ΣG V =41470+2450=43920N

[0156] (4) The bending moment on the mast is (the uniform wind pressure on the mast is 420 N / m considering the climbing coefficient of 1.1)

[0157]

[0158] 2. Horizontal load distribution of the pole

[0159] In addition to the central pressure, the pole also bears the horizontal wind load, the distribution diagram of which is shown in the figure Figure 2 Point A is the guy wire hanging point (rotation point), point B is the guy wire of the top waist hoop of the assembled tower, and point C is the waist hoop adjacent to the top waist hoop, with a spacing of 8m.

[0160] P1 is the wind load acting on the top of the boom, which is 14N; P2 is the wind load acting on the section of the boom where the rocker arm is located, that is, P2=105×2+14=224N.

[0161] q1 is the uniform load acting on the mast. Considering the influence of the ladder, multiply it by the coefficient 1.1, then q1=382×1.1=420N / m;

[0162] q2 is the uniform load acting on the main pole of the boom. Considering the influence of the ladder, multiply it by a coefficient of 1.1. Considering the wind load of the lifting rope, we can get

[0163] q2=382×1.1+1.5×2=423N / m

[0164] 3. Calculation of support reaction force and bending moment

[0165] When the moments of inertia of each section of the pole are equal, the simplified formula of the three bending moment equations is:

[0166] M n-1 l n +2M n (l n +l n+1 )+M n+1 l n+1 =-6(B n +A n )

[0167] For uniform load within the span

[0168]

[0169] Where M n-1 、M n 、M n+1 —Principal bending moments at points n-1, n, and n+1, kN·m;

[0170] l n , l n+1—The distance between the left and right points of n points, m;

[0171] A n , B n —are the calculation parameters of span uniformly distributed load.

[0172] like Figure 2 As shown, it is known

[0173] M C =0

[0174]

[0175] Substitute the known conditions into the formula

[0176]

[0177] Get M B =442.6N·m

[0178] The support reaction force at each section point is

[0179]

[0180] 4. Calculation of static tension of the pole cable

[0181] (1) Calculation conditions. The angle between the tension wire inside the pole and the horizontal plane is α = 60°, the angle between the tension wire resultant line and the ground plane is α1 = 67.79°, and the angle between the tension wire and its resultant line is θ = 20.71°.

[0182] The horizontal force acting on the cable hanging point is R A =4.4kN.

[0183] (2) Calculate the static tension of the wire. Assume that the static tension of the wire is P L ,but

[0184]

[0185] (3) The pressure exerted by the pull wire on the holding pole is

[0186] N L =R A tanα1=4.4×tan67.79°=10.89kN

[0187] 5. Calculation of the central pressure of the main pole

[0188] Known conditions: The cross-section of the pole is □400×400, and the verification length is 10m.

[0189] The pole center pressure includes the following items:

[0190] (1) The self-weight of the pole is

[0191] (110×3+175)×10=5050N

[0192] (2) Central pressure of the mast

[0193] ΣG V =43920N

[0194] (3) The self-weight of the rocker arm is 125×2×10=2500N

[0195] (4) The downward pressure of the lifting block is 2T 1N =2×11002=22004N

[0196] (5) The pressure exerted by the pole pull wire on the pole is 10890N

[0197] (6) The self-weight of the climbing rope is 4×2×10=80N

[0198] The center pressure of the pole is

[0199] ΣG1=5050+43920+2500+22004+10890+80=84444N

[0200] 6. Strength verification of mast

[0201] Known conditions: The cross section of the pole is □400×400, the verification length is 4m, the main material is ∠50×5 (the cross section area of ​​the angle steel is f1 = 4.803cm 2 , A=19.212cm 2 , J x =11.21cm 4 , Z0=1.42cm), Q355B material; auxiliary material ∠30×4 (angle steel cross-sectional area f1=2.276cm 2 , J x =1.84cm 4 , Z0=0.89cm), Q235B material.

[0202] According to the known conditions, the moment of inertia of the cross section of the pole is obtained:

[0203]

[0204] According to the moment of inertia of the pole section, the bending section coefficient of the pole section is obtained

[0205]

[0206] The rotation radius of the pole is

[0207]

[0208] The slenderness ratio of the pole is

[0209]

[0210] The calculated slenderness ratio is

[0211]

[0212] The stability coefficient of the compressive member is obtained by looking up the table

[0213]

[0214] The calculated stress is

[0215]

[0216] The safety factor of the pole is

[0217]

[0218] In actual use, the horizontal displacement of the top of the pole should not exceed 1.24H / 100 (H is the free height of the pole), that is, 12.4cm.

[0219] 7.Strength verification of rocker arm

[0220] Calculation conditions: Assuming the arm length is L1, the mast height is H1, L1 = H1 = 4m, such as Figure 3 As shown, the angle between the luffing rope and the rocker arm is α=45°, the vertical hoisting weight of the rocker arm is 1000kg (10000N), and the maximum deflection angle of the hanging part is 5°.

[0221] (1) Force analysis of rocker arm

[0222] Calculation of center pressure

[0223] When the angle between the luffing rope and the rocker arm axis is 45°, the comprehensive pressure N of the rocker arm in the lifting component state y for

[0224]

[0225] (2) Stability verification of rocker arm under center pressure

[0226] The main material of the rocker arm is No. 8 rectangular steel, and the two rectangular steels are welded with rectangular steel and Φ18×2 round pipe to form a V-shaped plane truss. For safety reasons, the main material of the rocker arm is subjected to stress as follows Figure 4 As shown. Assume that the angle between the two main materials of the rocker arm is θ, then

[0227]

[0228] Where b is the width of the opening at the connection between the rocker arm and the pole, which is 43cm.

[0229] Assume the pressure on the main material of the rocker arm is N y1 ,but

[0230]

[0231] The stable compressive stress of the main material of the rocker arm is σ y1 for

[0232]

[0233] Where A0—Cross-sectional area of ​​the main material of the rocker arm, cm 2 ;

[0234] ψ—Stress reduction coefficient of the compression rod under central compression state, which can be obtained by looking up the table based on the slenderness ratio λ.

[0235]

[0236] Where μ is the compression rod conversion coefficient, which is 1.0 based on the hinged support at both ends;

[0237] r—Rectangular steel inertia radius, cm.

[0238] Substituting the known conditions into the equation, we get

[0239]

[0240] It is known that the No. 8 rectangular steel is Q235, r = 2.692cm, A0 = 10.356cm 2 ,but

[0241]

[0242] From the table, we get ψ=0.353, then

[0243]

[0244] Calculated according to the stability coefficient of 2.0, the allowable stability stress [σ] of Q235 steel is 11750N / cm 2 , which is much larger than the calculated stress, and therefore meets the design requirements.

[0245] 8. Main pole strength verification

[0246] Known conditions: The cross section of the pole is □400×400mm, the verification length is 10m; the main material is ∠50×5 (the cross section area of ​​the angle steel is f1=4.803cm 2 , A=19.212cm 2 , J x =11.21cm 4, Z0=1.42cm), Q355B material; auxiliary material ∠30×4 (angle steel cross-sectional area f1=2.276cm 2 , J x =1.84cm 4 , Z0=0.89cm), Q235B material.

[0247] According to the known conditions, the moment of inertia of the cross section of the pole is obtained:

[0248]

[0249] According to the moment of inertia of the pole section, the bending section coefficient of the pole section is obtained

[0250]

[0251] The rotation radius of the pole is

[0252]

[0253] The slenderness ratio of the pole is

[0254]

[0255] The calculated slenderness ratio is

[0256]

[0257] The stability coefficient of the compressive member is obtained by looking up the table

[0258]

[0259] Calculate the bending stress of the pole. Considering the influence of wind load, the bending moment of the top hoop wire section of the main pole is 536700N·cm, so the calculated stress is

[0260]

[0261] The safety factor of the pole is

[0262]

[0263] Therefore, the pole meets the design requirements.

[0264] 6. Strength verification when unbalanced lifting weight (unbalance coefficient 25%)

[0265] 1. Calculation conditions

[0266] (1) One-side hoisting weight is 10kN, and the opposite side balance hoisting weight is 7.5kN;

[0267] (2) The wind speed is 13m / s.

[0268] 2. Central pressure of the mast

[0269] (1) The vertical pressure caused by the amplitude modulation pulley group is 11625N on one side and 9125N on the other side.

[0270] G F =11625+9125=20750N=20.75kN

[0271] (2) Static tension of the amplitude modulation rope: 9110N on one side and 7150N on the other side

[0272] (3) The mast’s deadweight is G V =2450N

[0273] (4) The central pressure of the mast is

[0274] ΣG V =39460N

[0275] 3. Horizontal load distribution and support reaction force of the holding pole

[0276] (1) The horizontal load generated by the boom due to the wind load and the unbalanced lifting load is as follows: Figure 2 As shown in the figure, the horizontal tension difference at the top of the mast is 2500N.

[0277] q1=420N / m,q2=423N / m

[0278] P1=14+2500=2514N

[0279] P2=-2500+224=-2276N

[0280] (2) Bending moment calculation

[0281] Known M C =0

[0282]

[0283] Substitute the known conditions into the formula

[0284]

[0285] Get M B =3245N·m

[0286] The bending moment distribution is as follows Figure 5 shown.

[0287] (3) Calculation of support reaction. The support reaction at each section point is

[0288]

[0289] 4. Calculation of static tension of wire

[0290] (1) The calculation conditions are the same as the load of 10kN on both sides at the same time. The horizontal force acting on the hanging point of the cable is

[0291] R′ A =7975-2276=5699N=5.699kN

[0292] (2) Calculate the static tension of the wire. Assume that the static tension of the wire is P L ',but

[0293]

[0294] According to the above calculation, when the load is unbalanced, the wire is subjected to the greatest force, so the breaking force of the wire should satisfy

[0295] P Q ≥8.14×4.8=39kN

[0296] Choose Φ9 steel wire rope (6×19 type, σ b =1770MPa), T b =47.3kN>39kN, meets the requirements.

[0297] (3) The pressure exerted by the pull wire on the holding pole is

[0298] N L =R A tanα1=5.699×tan67.79°=14.1kN

[0299] 1. Strength verification of the main pole

[0300] Basic parameters and slenderness ratio are the same as above

[0301] (1) The central pressure is

[0302] ∑G1=5050+39460+2500+22004+14100+80=83194N

[0303] (2) The calculated bending stress of the main pole is:

[0304]

[0305] The safety factor of the pole is

[0306]

[0307] Therefore, the pole meets the design requirements.

[0308] 6. Strength verification of mast

[0309] The basic parameters and slenderness ratio are the same as the above calculation results. The bending moment at the bottom of the mast is

[0310]

[0311] The main material of the mast bottom section is ∠50×5 (angle steel cross-sectional area f1 = 4.803cm 2 , A=19.212cm 2 , J x =11.21cm 4 , Z0=1.42cm), Q355B material; auxiliary material ∠30×4 (angle steel cross-sectional area f1=2.276cm 2 , J x =1.84cm 4 , Z0=0.89cm), Q235B material.

[0312] According to the known conditions, the moment of inertia of the cross section of the pole is obtained:

[0313]

[0314] According to the moment of inertia of the pole section, the bending section coefficient of the pole section is obtained

[0315]

[0316] The calculated bending stress of the mast is

[0317]

[0318] The safety factor of the pole is

[0319]

[0320] Therefore, the mast can meet the strength requirements

[0321] 7. After the whole set of poles (total height 69m) are assembled, the strength of the bottom section of the pole is verified

[0322] After the whole set of poles (total height 69 meters) are assembled, under rated load, the comprehensive pressure on the pole center includes the main pole center pressure of 84444N and the self-weight pressure of the 55m pole standard section of 20550N.

[0323] After the whole set of poles are assembled, the strength of the poles below the lowest waist hoop is verified, and the length is 10 meters. The known conditions are: the cross section of the pole is □400×400mm, the main material is ∠50×5 (the cross section area of ​​the angle steel f1=4.803cm 2 , A=19.212cm 2 , J x =11.21cm 4 , Z0=1.42cm), Q355B material; auxiliary material ∠30×4 (angle steel cross-sectional area f1=2.276cm 2 , Jx =1.84cm 4 , Z0=0.76cm), Q235 material.

[0324] According to the known conditions, the moment of inertia of the cross section of the pole is obtained:

[0325]

[0326] According to the moment of inertia of the pole section, the bending section coefficient of the pole section is obtained

[0327]

[0328] The rotation radius of the pole is

[0329]

[0330] The length below the lowest waist ring of the pole is L = 10m, and its slenderness ratio is calculated as (μ is approximated to be 1.05)

[0331]

[0332] The calculated slenderness ratio is

[0333]

[0334] From the table (Q355), the stability coefficient of the central compression member is

[0335]

[0336] The calculated stress is

[0337]

[0338] The safety factor of the pole is

[0339]

[0340] Therefore, the pole can meet the strength requirements after being fully assembled.

[0341] 8. Self-weight stress calculation

[0342] Section A is located 0.5m from the bottom of the pole:

[0343] Self-weight stress of section A PA = N / A = 15.81 MPa;

[0344] Section B is located 1m below the pole rotating device:

[0345] Self-weight stress of section B PA = N / A = 13.87 MPa;

[0346] Section C is located 0.5m above the rotating device:

[0347] Self-weight stress of section C PA = N / A = 2.81 MPa;

[0348] Section D is located at the top of the mast:

[0349] Self-weight stress of section D PA = N / A = 2.59 MPa;

[0350] Section E is located at the root of the rocker arm:

[0351] Self-weight stress of section E, PA = N / A = 2.62 MPa;

[0352] Section F is located at the midpoint of the rocker arm:

[0353] Self-weight stress of section F, PA = N / A = 8.16 MPa;

[0354] Section G is located at the top of the rocker arm:

[0355] Self-weight stress of G section PA = N / A = 1.55MPa;

[0356] IX. Conclusion

[0357] In summary, the strength calculation of the ground-mounted four-arm pole holder is qualified, and both meet the requirements of DL / T 319-2018 "General Technical Conditions and Test Methods for Overhead Transmission Line Construction Pole Holders" and DL / T 875-2016 "Basic Technical Requirements for Overhead Transmission Line Construction Machinery and Tools".

[0358] The provisions in the specification meet the design requirements.

[0359] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for assembling a floor-standing double rocker arm, characterized in that: The assembly method comprises the following steps: Step 1: Install the fixed base; ensure that the fixed base is flat and compacted. To prevent the rod assembly from sinking or tilting, dig the site and level the site; When the site is made of hard soil, loose sand and gravel, mudstone, sandstone or other relatively hard soil, level the site and lay a layer of gravel on it, and then place the fixed base on the site; When the site is relatively soft soil such as ordinary soil or clay soil, foundation treatment is required. The site endurance value must be greater than or equal to 150kPa, and then road timber or steel is used on the site; Step 2: Install the base cable and tighten it, and ensure that the load of the corresponding tool is not less than 50kN. Adjust the base cable on one side of the lower part of the fixed base to the same height as the cable on the opposite side; Step 3: Install the jacking frame on the fixed base while paying attention to the opening direction and the pulling direction, arrange the position of the hydraulic operating table reasonably, and install the pull wire and other components in time; after the main structure of the jacking frame is installed, install the remaining structure of the jacking frame; Step 4: Install the rocker arm assembly; the rocker arm assembly must be arranged symmetrically along the line or the horizontal line and on both sides of the opening direction of the lifting frame. Use the top of the mast assembly to hoist the rocker arm assembly to the slewing connection, install the pin shaft, and check the connection of each component; Step 5: After the assembly is completed, check the pole assembly to see if the supporting tools are operating normally and the tight connection between the components; check if the wire rope is threaded correctly and if there is any interference; check if there is any debris on the pole. After the pole is assembled, the no-load test and load test should be carried out in sequence; hoist the pole at the maximum amplitude to 25%, 50%, 75%, and 100% of the rated lifting weight respectively, and test according to the tight connection requirements between the components; Step 6: During use, as the height of the pole assembly is continuously increased, the lifting height of the double rocker arm boom also needs to be continuously increased. Remove the bolts connecting the pole body and the fixed base, hoist the pole body, use the hanger on the jacking sleeve to lift multiple groups of first standard sections and second standard sections on the pole body, use the roller lifting assembly on the jacking sleeve to perform mechanical lifting, and stop after the lifting exceeds the length of any group of first standard sections or second standard sections. Place any group of first standard sections or second standard sections into the jacking sleeve, slightly lower the lifted part, install the connecting bolts, and repeat the jacking and heightening operation until the installation is completed, and then lock it with the tower body with bolts; Step 7: Install the waist ring; hoist one waist ring half frame with rollers installed to the desired derrick installation position, hoist the other waist ring half frame with rollers installed to the first waist ring half frame and connect them together. Do not tighten them at this time, adjust the upper and lower positions of the waist ring, install the pull rope and anti-sinking pull line, so that the rollers in all directions of the waist ring can support the rod assembly, and lock them after the waist ring position is determined.

2. A method for disassembling a ground-mounted double rocker arm, characterized in that: include Step 1: Lower the hooks on the first rocker arm and the second rocker arm of the rocker arm assembly to the ground and place them firmly, and remove the hooks; Step 2: After the hook is removed, the first rocker arm and the second rocker arm are lifted and lifted to both sides of the fixed mast of the mast assembly to fix them into a whole; Step 3: Remove the rocker arm assembly, rotate the slewing bearing by ±45°, and remove the first standard section, second standard section, base section, mast assembly, lifting sleeve and other parts in turn, and finally remove the fixed base.

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