The limiter of tower crane often breaks down. Why?

1. Classification: 1. Simple action type: lifting can only complete one spatial action, including: jack, winch, winch and elevator; 2. Complex action type: generally, there are three directions of motion mechanisms, which are divided into bridge cranes and jib cranes. (1), bridge crane: it takes the bridge as the load-bearing component and moves in the three coordinate directions of X (horizontal), Y (vertical) and Z (height) by means of trolley walking, bridge rail lifting and hook lifting. There are gantry cranes, factory cranes and so on. , mainly used in ports, yards, factories, etc. (2) Rotating jib crane: The jib and the tower are the load-bearing components, which move in the three coordinate directions of H (height), R (radius) and θ (angle) by means of hook lifting, trolley walking and jib rotation, and are divided into two types: fixed and mobile, mainly including tower crane and truck crane.

Figure 1 bridge crane rotating arm crane II. Main technical parameters: 1, lifting weight (KN) and lifting torque (kn m); 2. Height (m): lifting height (m), independent height (m) and free height (m); 3. Span (m) and amplitude (m); 4. Working speed: speed V (m/min) and speed N (rpm). The second part of the tower crane The tower crane is a crane with a vertical tower body, a lifting arm and a balance arm hinged under the tower cap, which can rotate 360 degrees. It has the characteristics of large lifting height, long luffing radius, wide turning angle, high working efficiency, convenient operation and reliable operation. Because the tower crane is tall and upright, its structure is complex, its disassembly and assembly are frequent, and its technical requirements are high, it also brings certain difficulties to the safe construction and production, and it is prone to overturning and collapse accidents. The safe installation, disassembly and operation of tower crane are particularly important. 1. Classification: 1. According to the boom structure, it can be divided into horizontal boom and movable boom, which also determines the different luffing methods; 2. According to the rotation mode, it can be divided into upward rotation and downward rotation; 3. According to whether there is a walking mechanism, it can be divided into walking type and fixed type (including fixed attachment type and internal climbing type); The common tower cranes in construction sites are cross-arm, upward-rotating and fixed-attached. The models are usually represented by QT80, QTZ 120, QTZ50 13, F0/23B, etc. Second, the working principle: three working mechanisms: lifting, luffing and slewing mechanisms, which rely on three working mechanisms for vertical and horizontal transportation of heavy objects; The hydraulic jack-up mechanism realizes jack-up and joint-adding, so that the tower crane keeps rising with the building; The track walking type also has a walking mechanism to make it walk on the subgrade track and change its working position. 3. Structure: Figure 2 (1). Metal structure: 1. Foundation, underframe and ballast: the tower body and foundation are fixed with footbolts or underframe (ballast); 2. Tower body: It consists of a reinforced section (lower tower body) and a standard section, each section is connected by eight high-strength pins or bolts (with the bolts facing downwards), and the upper end is connected with a rotating lower bracket; 3. Climbing frame: it is sleeved outside the standard section, and its upper end is connected with the rotating lower bracket, which consists of a frame, a working platform, a standard section lead-in device, etc. 4. Rotating bearing: it is divided into two parts: upper bearing and lower bearing. The lower bearing is connected with the tower body and jack-up jacket to keep static, and the upper bearing is connected with the rotating tower body to rotate together with the upper part of the tower crane. 5. Rotating tower body: the lower end is connected with the rotating upper bracket, the upper part is connected with the tower cap, the front and rear ear plates are connected with the lifting arm and the balance arm respectively, and the cab is installed on it; 6. Tower cap: an inclined cone, the lower end of which is pin-connected with the rotating tower body, and the upper end of which is connected with the lifting arm and the balance arm through a pull rod to keep the two arms horizontal; 7. Derrick: It consists of a plurality of arm joints connected with each other, the heel of which is pin-connected with the rotating tower body, and is connected with the top of the tower cap through two pull rods, and the luffing mechanism is arranged on it; 8. Balance arm: divided into two sections, the heel of which is pin-connected with the rotating tower body and connected with the top of the tower cap through a pull rod, and there are railings and walkways on both sides, on which there are counterweight, lifting mechanism and power distribution cabinet;

9. Wall-attached device: use wall-attached frame and wall-attached pillar to attach to the building. Fig. 2 Schematic diagram of tower crane structure (II), working mechanism: 1, hoisting mechanism: consisting of hoisting motor, main hoist, reducer, brake, sheave, hook, wire rope, etc. , and provide power for tower crane hoisting; 2. luffing mechanism: it consists of luffing motor, reducer, brake, hoist, trolley, wire rope, etc. To provide power for the truck to luff outward and inward along the boom guide rail; 3. Rotary mechanism: it consists of a big gear ring, two sets of motors, a reducer, a brake and a pinion. And provides power for the upper rotation of the tower crane. (3) Hydraulic jacking mechanism: it is installed on the jacking frame and consists of motor, hydraulic oil pump, oil cylinder, jacking beam, etc. It is a hydraulic working device for tower crane to increase and decrease cross section; (4) Walking mechanism: used on crawler-type walking tower crane, consisting of two driving trolleys and two passive trolleys, diagonally arranged. The driving trolley is composed of motor, hydraulic coupling, worm gear reducer, brake and walking wheel, which provides power for the tower crane to walk along the track. (5) Internal climbing mechanism: used on internal climbing tower crane, consisting of supporting beam, climbing frame, anchoring frame and hydraulic climbing device. , make the tower crane anchored on the building, and gradually climb up. Four. Safety device: "two limits, three limits and two guarantees" 1. Lifting torque limiter: The rated lifting torque (M=FR) of the tower crane is constant, which is used to control the lifting torque of the tower crane and prevent the tower crane from overturning due to torque overload. When the weight is overweight or the working radius is too large, and the lifting torque exceeds the technical performance of the tower crane, it can automatically cut off the power supply in the ascending and luffing directions, and the mechanism can only move in the descending and luffing directions. There will be a lifting performance table or a lifting performance diagram (Figure 3) in the instruction manual of the tower crane, and the corresponding lifting weight should be specified for a certain working range. The lifting moment limiter is mainly mechanical, and it adopts a spring bow-plate limiter (Figure 4), which is generally installed on the chord of the tower cap at one side of the lifting arm. The spring bow plate is deformed by compression, and the bolt head contacts the contact of the travel switch to act; It is also installed on the chord on one side of the balance arm of the tower cap, and its spring bow plate is concave and deformed by tension, and the bolt head contacts the contact of the travel switch to act. The lifting torque limiter should be adjusted strictly according to the requirements of the instruction manual, and the constant load amplitude (deceleration operation) and constant amplitude variable load (early warning) tests should be carried out respectively to control the corresponding travel switch. When the boom length and wire rope ratio change, the moment generated by the boom and wire rope will be reflected in the load, and it is generally not necessary to reload.

Adjust the lifting torque limiter. 2. Lifting capacity limiter: the maximum lifting capacity of the tower crane remains unchanged, and the power of the lifting motor remains unchanged (P=FV). The lifting limiter responds to the force of the lifting wire rope, and is used to control the lifting weight of the tower crane and the lifting speed of the hook under a certain lifting weight, so as to prevent the tower crane structure from being damaged due to the lifting weight and the overload of the lifting motor. The lifting capacity limiter is arranged between the rotating tower body and the tower cap, and has three limit switches, which respectively correspond to light, medium and heavy lifting capacity and high, medium and low lifting speed limits. When the lifting weight exceeds the rated weight of the corresponding lifting speed gear, the power supply of the speed gear will be automatically cut off, and the speed gear can only be lifted at a lower speed; When the lifting capacity reaches the maximum rated lifting capacity, cut off the lifting main power supply, and the mechanism can only move downward. Generally, there are two kinds of structures: the load-measuring ring lifting limiter (Figure 5 Sichuan Construction Machine), which makes the load-measuring ring stretch and deform through the tension generated by the lifting wire rope, and the bolt head contacts the contact of the travel switch; Spring-pull-rod load limiter (Figure 6, at the bottom of the river) works through spring-pull rod, rubber block and travel switch.

The lifting limiter must also be adjusted in strict accordance with the requirements of the instruction manual, and the light, medium and heavy loads should be tested separately, and the corresponding three travel switches should be controlled. When the wire rope ratio changes, such as 2 to 4, the lifting weight of the corresponding lifting mechanism is doubled, the lifting speed of the hook is doubled, and the stress of the wire rope remains unchanged, so it is not necessary to readjust the lifting weight limiter; When the boom length changes, there is no need to readjust. 3. Lifting height limiter: also called superelevation limiter, it is used to control the lifting height of the hook and prevent the hook from colliding with the trolley and boom. When the top of the hook device is at a certain distance from the lower end of the trolley frame (2 times ratio is not less than 1m, and 4 times ratio is not less than 0.7m), the lifting power supply is automatically cut off, and the hook can only descend, but not ascend. The lifting height limiter is installed at the end of the drum of the lifting winch, connected with the drum through the pinion and reducer, and rotates together. According to the recorded number of turns of the drum, the length of the winding wire rope, that is, the lifting height position of the hook, is known. When the hook moves to the highest position, the protrusion in the stopper contacts the contact of the travel switch and cuts off the power supply. When the hoisting height changes, the length of the wire rope released and retracted by the hoisting winch drum is equal, and the length of the wire rope required between the highest position of the hook and the drum remains unchanged, so it is not necessary to readjust the hoisting height limiter; When the boom length changes and the wire rope ratio changes, it is necessary to readjust the superelevation limiter. 4. Limiter: used to control the running range of the trolley and prevent the trolley from hitting the end and heel of the boom. When the car moves to a certain position, it can automatically slow down, and when it continues to move to the limit position, it will automatically cut off the forward power supply, so that the car can only retreat and cannot move forward, and ensure that when the electrical device fails, the buffer and stop device can make the car stop on the boom stably. A limiter is installed at the end of the drum of the luffing winch, and the running position of the trolley can be known according to the recorded drum revolutions. The working principle is the same as the lifting height limiter. Buffer and stop device should be set at the operating terminal position of the boom end and heel. When the limiter acts, it must be ensured that the distance between the end of the trolley and the buffer device is not less than 0.2m, and the distance between the buffer stop device and the end or heel of the boom is not less than1m.. 5. Rotation limiter: For the tower crane with no current collector in the rotating part, a rotation limiter should be set to control the number of positive and negative turns of the tower crane, so as to prevent the tower crane from running in one direction without restriction, resulting in cable winding and twisting. The slewing limiter is installed next to the slewing mechanism, which is connected with the big gear ring through the pinion and reducer to rotate together, thus recording the number of positive and negative rotations of the tower crane. Its working principle is the same as that of the lifting height limiter. When the rotation of the tower crane reaches the limit position (generally around 540 degrees), the power supply of the forward rotation will be automatically cut off, so that the tower crane can only run in the reverse direction. 6. Hook safety device: refers to the spring gland installed on the hook. The gland cannot be opened upward, but can only be pressed downward to prevent the sling from falling off the hook and causing heavy objects to fall. The damage of hook safety device must be repaired in time, and steel bars cannot be used instead. Welding and drilling hooks are strictly prohibited. 7. Drum and pulley safety device: refers to the blocking device installed at the edge of drum and pulley side plates of hoisting winch and trolley winch to prevent the steel wire rope from crossing the flanges of drum and pulley side plates, resulting in rope tripping, rope jamming or even cutting. The minimum clearance between the device and the outermost edge of the side plate of the drum or pulley should be less than 20% of the diameter of the wire rope. 8. Travel limiter: used for traveling of the tower crane to control the traveling stroke of the tower crane and ensure that the tower can automatically stop on the running track. The travel limiter must be set in two running directions at the same time, including travel switches installed at both ends of the walking trolley and iron bumpers at both ends of the travel. When the tower crane runs to a certain position, the travel switch collides with the iron stop, which automatically cuts off the power supply for walking, so that it cannot move forward but only retreat. When parking, ensure that the distance between the end of the tower crane and the buffer is not less than 1 m. 9. Buffer and stopper: used to prevent the tower crane from derailing and overturning, including buffers and terminal stoppers arranged at both ends of the track to ensure that the tower crane can be buffered and blocked when the walking stopper fails, and can stop on the track smoothly without being violently impacted. The distance between the buffer and the terminal brake is not less than 65,438+0 meters. 10. There are four rail clamps: * *, which are installed on the traveling wheels of the traveling trolley and used to clamp the traveling wheels of the tower crane when the tower crane is not working, so as to prevent the tower crane from being blown by the wind and causing accidents by itself. Safety devices 165438+ items 1~5 and 8 are required to be debugged once every six months. Equipment users and installers are required to debug together to check whether they meet the safety requirements. Once debugged, no one is allowed to transfer at will. When it is necessary to transfer, the relevant units are also required to do it together. 1996 Donghai Garden Phase I crane collapsed due to overload caused by manual adjustment of lifting torque limiter (Shenzhen No.1 Construction). V. Foundation: The tower crane foundation mainly bears the weight of the tower crane, overturning moment, horizontal force and self-weight of the foundation. There are square plate foundation, beam foundation and pile foundation. The operating instructions of the tower crane will indicate the load parameters (Table 1) under working and non-working conditions, and users should design and manufacture concrete foundations according to these load parameters. If the site foundation conditions permit, the user can make the foundation according to the foundation form recommended in the instruction manual, including the length, width and thickness of the foundation, the embedding of anchor bolts, fixed legs or embedded joints, foundation reinforcement, concrete grade and ballast setting, etc. The foundation should have reliable drainage measures, such as a pool for pumping water when the foundation is located outside the building; If the foundation is integrated with the basement floor, raise the foundation surface to prevent water accumulation. When the local foundation conditions are insufficient, the design and calculation of tower crane foundation must meet the requirements of foundation bearing capacity and overturning stability. The calculation of overturning stability should be based on load parameters in non-working state, and the calculation of foundation bearing capacity should be based on working state. See GB/T 13752- 1992 Code for Design of Tower Cranes for details. Take the square slab foundation as an example to illustrate the design and calculation of tower crane foundation, as shown in Figure 7. Six, attached to the wall:

The independent height, wall spacing and free height of fixed attached tower crane are strictly required in the manual. When the installation height needs to exceed the independent height or free height specified after the wall is attached, reliable wall-attached connection must be made according to the requirements of the instruction manual. The wall-attached device of tower crane mainly bears overturning moment, torsion moment and wind load. It is very important to ensure the vertical stability of tower crane to adopt wall-attached bars and connection methods that meet the requirements of strength and stiffness. In fact, the wall-attached pole bears axial tension or pressure, which can be simplified into four forces: F 1, F2, F3 and F4 (Figure 8). For the wall-attached connection in general, the forces of F 1, F2, F3 and F4 are explained in the operating instructions of the digital tower crane in working and non-working conditions. In the case of special wall attachment, the values of forces F 1, F2, F3 and F4 should be obtained by the mathematical method of extreme value according to the overturning moment and the direction of wind load. After the values of F 1, F2, F3 and F4 are obtained, the strength and rigidity of the wall-attached device are checked, mainly including the stability, tensile strength, pin shaft, connecting plate and welding strength of the wall-attached rod. Under normal circumstances, the distance between the attached walls is 5 meters, the span of the attached walls is about 8 meters, the length of the attached wall members is less than 8 meters, and the angle should be 90. The manufacturer's original wall attachment device should be used as far as possible. Under special wall-attached conditions, tower crane manufacturers should be consulted to design wall-attached devices under such conditions. Before attaching the wall, the embedded parts should be buried firmly, and local reinforcement should be added when necessary to ensure the reliable strength of the attachment points. Deviation of verticality of tower: 1. When not attached, the verticality deviation of the independent height of the tower body should not be greater than 4 ‰; 2. The verticality deviation of the attachment point is not greater than 65438 0 ‰; 3. The verticality deviation of the attached free end is not more than 2.5‰. During the initial installation and attachment of tower crane, theodolite should be used to check the verticality of tower body and make adjustments to ensure that it meets the requirements. Especially before attachment, the tower must be leveled with trolley and standard section, and the trolley and rotation must be kept still before attachment and fixation such as welding can be carried out. Seven. Stair-climbing fixer: A person climbing a ladder on a tower crane must set a fixer 2 meters above the ground. When the ladder is arranged inside the tower body, and the tower body structure meets the following conditions, and the side structure does not allow balls with a diameter of 0.6m to pass through, there is no need to set a retainer: 1, and the ladder is arranged along the long side of the tower, and the length of the tower side is not more than 0.75m; 2. The ladder is arranged diagonally along the tower body, and the length around the tower is not more than 1. 1 m.. The diameter, maximum spacing, transverse vertical slats and bearing capacity of the retainer have specific requirements. See GB5 144—2006 Safety Regulations for Tower Cranes for details. Eight, access to the tower: when you need to climb the tower crane through the building floor or scaffolding, you must set up a reliable access to the tower, which requires stability, set up protective railings, hang a safety net, and it is strictly forbidden to climb from scaffolding. 9. Electrical device: 1, special switch box: isolating switch and leakage protector are set, and the working current of leakage protector is not more than 30mA；; 2. Protect the grounding body to the zero line of the distribution box at the top of the tower with a five-core cable and fix it reliably; 3, reliable lightning protection grounding, grounding resistance is not more than 4 ω, and connected to the construction site protection zero system; The insulation resistance of the main circuit and the control circuit is not less than 0.5MΩ；; 4. There is no need to set lightning rod and down lead. X. Safe distance: 1. The horizontal distance between the boom end of the low-position tower crane and the tower body of the high-position tower crane is not less than 2m; 2, the vertical distance between any part of the high and low tower crane is not less than 2 meters; 3. The safe distance between any part of the tower crane and the overhead transmission line shall meet the requirements: (Table 2) Table 2 Safe distance voltage between the tower crane and the overhead transmission line (kV) <11520 ~ 4060 ~10220 Safe distance. 3, oblique hanging, lifting underground buried heavy overload; 4. When the wind force exceeds the specified range, jack-up or hoisting operation shall be carried out (Level 4: jack-up and installation are not allowed; Level 6: No hoisting); 5. When the wind is strong, the slewing mechanism cannot guarantee the free rotation of the boom; 6. The independent height and free height of the tower body exceed the specified value, and no wall is attached; 7. The verticality of the tower does not meet the requirements, and the center of gravity moves out too much; 8. The counterweight and ballast are too small and the position is incorrect; 9, steel structure fatigue damage, corrosion, weld cracking; 10, wire rope and sling are damaged, resulting in the sudden fall of heavy objects. (2) "Ten Don't Lift": 1, overloaded or the weight of the lifted object is unclear; 2, the command signal is not clear; 3. The binding and hanging are not firm or balanced; 4. There are people or floating objects on the hanger; 5. Oblique hanging; 6. The workplace is dimly lit; 7. There is no gasket between the corner of the hoisted object and the binding wire rope; 8. Buried objects; 9, flammable and explosive; 10, the structure or parts are damaged or have safety defects. 200 1 Crystal Island subway station collapsed during jacking (Shenzhen Municipal Company). In 2000, the rotary welding seam of tower crane in Bantian construction site (China Railway Construction Bureau) cracked and collapsed. On March 30th, 2008, the welding seam of tower crane underframe cracked and collapsed in Xindu construction site of Longgang seaside in Fan Hua, Shenzhen. (3) Matters needing attention in installation, disassembly, jacking and connection of tower crane: 1. Before each installation, disassembly, jacking and jointing, the oil quality and oil level of hydraulic oil must be carefully checked, and the hydraulic oil, oil filter and air filter should be replaced regularly (every 1500 working hours). When replacing, all the old oil must be drained and cleaned, and any sundries and water are prohibited from entering the hydraulic pump station; 2. Before jack-up and joint operation, the reliability of hydraulic system must be carefully checked, especially whether the sealing ring and piston cylinder at the hydraulic pump station and pipeline joint are fastened, whether the balance valve and hydraulic lock are reliable and whether there is oil leakage; Jack-up and joint operation in each shift must start from jack-up 10~20cm, stay for 2 minutes, and repeat several times to check the reliability of hydraulic system and metal structure, which is beneficial to the rise of oil temperature and the flexible action of control valve, and it is not allowed to tighten pipes or connection points under the pressure of hydraulic system; 3. Before the jack-up operation, the moment balance of the front and rear arms of the tower crane must be adjusted, that is, the gap between the 16 guide wheel on the climbing frame and the main chord of the tower is equal, generally 2~4 mm is appropriate. In order to adjust the balance of tower arm, the method of lifting standard section is generally adopted. Corresponding to a certain boom length, the position of the car on the boom is relatively fixed, and there will be hints in the instruction manual of the tower crane; 4. In the process of jacking the top of the tower, that is, when jacking the climbing frame, it is forbidden to rotate or jack up, and the position of the trolley can be adjusted appropriately to ensure the balance of the tower arm, but only when jacking the climbing frame for a short distance; 5. In the process of tower hoisting, two installers must be specially arranged to monitor the jack-up beam to ensure that the pin shafts at both ends of the jack-up beam correctly fall into the step grooves on the tower and do not shift during the jack-up process; 6, at the same time, in the process of jack-up, two installation workers must be specially arranged to monitor the climbing claw on the climbing frame to keep it vertical, so as to avoid collision with the steps on the tower during jack-up. After a trip of jack-up, it is necessary to ensure that the climbing claw correctly falls into the step groove on the tower. The correct state of climbing claw is especially important for dismantling tower crane and lowering climbing frame. 7. After jack-up twice, before hanging the standard, the rotary lower bearing must be effectively connected with the tower, and each corner must be connected with at least one bolt (at the foot of the river), or at least diagonally and reliably (in Sichuan), which must be strictly implemented in accordance with the instruction manual. On March 3, 2007165438+/KLOC-0, Longhua Bishui Longting Tower Crane collapsed in an incorrect state (Wu Jian, Fujian). Part III Safety Management The safety management of construction hoisting machinery includes leasing, property right registration and use registration, installation and disassembly, acceptance, inspection, use and supervision, etc. It is very important for all parties involved in the leasing, installation, disassembly, use and supervision of construction hoisting machinery to earnestly fulfill their respective safety responsibilities and improve various safety management materials to ensure the safe installation, disassembly and safe operation of construction hoisting machinery. Basis of normative documents: 1, Regulations on Safety Supervision and Management of Construction Hoisting Machinery (Order of Ministry of Construction166); 2. Measures for Safety Management of Construction Hoisting Machinery in Shenzhen (Shen Jian Zi [2006] No.214); 3. Notice of Guangdong Provincial Construction Department on Establishing the Registration Management System of Construction Lifting Machinery in Guangdong Province (Yue Jian An Zi [2007] No.88); 4. Notice on Strengthening the Supervision of Qualification and Safety Production License of Professional Contractors for Crane Installation and Elevator Installation Engineering (Guangdong Jian 'an Letter [2008]11); 5. Notice on Carrying out Safety Technical Training and Assessment for Special Operators of Construction Hoisting Machinery (Shen Jian Xie Zi [2008] No.02); 6. Notice on Strengthening Safety Management of Construction Hoisting Machinery (Shen Jian 'anzhi [2008] 143). 1. Property right filing: the construction cranes are registered and managed, and all construction cranes entering the construction site must go to the municipal construction safety supervision institution for property right filing and obtain the property right filing certificate. It is strictly forbidden for construction hoisting machinery that has been explicitly eliminated by the state, has no manufacturing license, no product certificate and has reached the scrapping condition to enter the construction site for installation and use. The following materials need to be submitted for the record of the property right of construction hoisting machinery: 1, a copy of the business license of the legal person of the property right unit; 2, special equipment manufacturing license; 3. Product certificate; 4, manufacturing supervision and inspection certificate; 5. Purchase and sale contracts, invoices or corresponding valid vouchers. 2. Lease: When using the construction hoisting machinery leased by other units, a lease contract must be signed with the leasing unit to clarify the safety responsibilities of both parties. In particular, it should be clear whether the leasing unit or the user or the installation unit is responsible for inspection, repair and maintenance. The leasing unit in the lease contract shall be consistent with the property right unit in the property right record certificate of construction hoisting machinery, and there shall be no clause in the lease contract that the leasing unit is responsible for the installation and disassembly of construction hoisting machinery. Three. Installation and disassembly: 1. Qualification of installation units and personnel: Units engaged in the installation and disassembly of construction hoisting machinery must have corresponding qualifications and safety production licenses, and undertake the installation and disassembly of construction hoisting machinery within the scope of their qualifications. Class III personnel of the installation unit of construction hoisting machinery must obtain the certificate of safety production assessment, and the installation and disassembly workers must pass the examination of the competent construction department and obtain the qualification certificate of special operations; 2. Installation and disassembly contract: When non-users install or disassemble the construction hoisting machinery, they must sign an installation and disassembly contract with the installation unit to clarify the safety responsibilities of both parties, especially the total installation height and initial installation height. If the installation unit is responsible for the total height installation of construction hoisting machinery, it must be clearly responsible for attaching walls and adding sections in the terms of the contract; If the installation unit is responsible for the inspection, repair and maintenance of construction hoisting machinery, it must also be specified in the contract terms; Shall not be directly signed by the rental unit and installation unit installation, demolition contract; 3. Installation scheme: The installation unit shall formulate a scientific and feasible special construction scheme for the installation and disassembly project according to the characteristics of the construction hoisting machinery, the requirements of the instruction manual, the engineering characteristics and the site conditions, and organize the installation and disassembly operation according to the requirements of the special construction scheme and the safety operation regulations. The special construction scheme for installation and disassembly works shall be compiled by the mechanical engineer of the installation unit, reviewed by the technical and safety departments, approved by the technical director, and implemented after being reviewed by the professional supervision engineer and project director. The special construction scheme of tower crane installation project shall include the following contents: (1), general situation of engineering and machinery: general situation of the project, installation quantity of building hoisting machinery, specifications and models, factory number, total installation height, initial installation height, etc. (2) Personnel arrangement: technical person in charge, full-time safety officer, general operation commander and special operators such as installers, drivers and commanders; (3) Lifting machinery and rigging equipment: lifting machinery, steel wire rope for installation, spreader and fixture equipment; (4) Foundation and attached wall design: plan, foundation design plan, attached wall plan, attached wall elevation, etc. Construction crane, if necessary, should be attached with the design calculation of foundation and attached wall; (5) Installation procedures: including the lifting operation procedures from underframe, ballast, standard section, climbing frame, slewing bearing and tower cap to balance arm, lifting arm and counterweight; (6) Jack-up and connection procedures: According to the requirements of operation manual and safety operation regulations, explain the whole operation procedures of jack-up and connection process in detail; (7) Safety protection measures: including unified command, cooperative operation requirements, personal labor protection, tools and parts falling prevention and warning measures in the operation area, etc. 4. Emergency rescue plan: At the same time, the installation unit must formulate an emergency rescue plan for production safety accidents in installation and disassembly projects, and improve the examination and approval procedures; 5. Installation (dismantlement) notice: Before the installation and dismantlement of construction hoisting machinery, the installation unit must submit the unit qualification, safety production license, list of installation and dismantlement personnel, operation qualification certificate, special construction plan and emergency rescue plan to the supervision unit for review, and then notify the construction safety supervision institution where the project is located in writing. Four. Acceptance: 1. Installation acceptance: After the installation of construction hoisting machinery is completed, the user should organize relevant units such as leasing, installation and supervision to carry out acceptance according to the contents and requirements of the installation acceptance sheet. Construction hoisting machinery can be put into use only after it has passed the acceptance, and it shall not be used without acceptance or unqualified acceptance; 2. Acceptance of wall-attached joints: After each completion of wall-attached joints and jack-up joints, users should also organize relevant units to conduct acceptance according to the contents and requirements of the wall-attached joint installation acceptance form. Construction hoisting machinery can be put into use without experience when it needs to be jacked up without being attached to the wall during use. 5. Inspection and test: Before the construction hoisting machinery is put into use, it must pass the supervision and inspection of inspection and test institutions with corresponding qualifications. Inspection and testing institutions and inspection and testing personnel shall bear legal responsibility for inspection and testing results and appraisal conclusions according to law. 1, newly installed and used at each transfer station; 2. Once a year after installation in the same place; 3. After the major fault is repaired; 4, the factory time more than a certain number of years, once every six months, see "seven, use". 6. Use registration: The user must go to the construction safety supervision institution where the project is located to register the use and obtain the use registration certificate within 30 days after the installation and acceptance of the construction hoisting machinery is qualified. Those who fail to submit the installation notice will not be registered for use. The following materials need to be submitted for the use registration of construction hoisting machinery: 1, property right registration certificate; 2. Installation acceptance form; 3, supervision and inspection report; 4, driver, conductor, operator operation qualification certificate; 5, construction hoisting machinery safety management system.