金得力重工(无锡)有限公司
 
 
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  History of cranes

  Orange used for irrigation in ancient China is the prototype of jib crane.

  In Fourteenth Century, a rotary boom crane was driven by manpower and animal power in Western Europe.

  In the early nineteenth century, bridge cranes appeared; the important wear parts of cranes such as shafts, gears and hangers began to be made of metal materials, and began to use hydraulic drive.

  In the late nineteenth Century, steam driven cranes gradually replaced hydraulic powered cranes.

  Since the 1920s, with the rapid development of the electrical industry and the internal combustion engine industry, various cranes powered by electric motors or internal combustion engines have been basically formed. Cranes mainly include lifting mechanism, operation mechanism, luffing mechanism, slewing mechanism and metal structure. Lifting mechanism is the basic working mechanism of the crane, mostly composed of hanging system and winch, but also through the hydraulic system to lift the weight.

  Operating mechanism is used to move weights horizontally and longitudinally or to adjust the working position of crane. It is generally composed of motor, reducer, brake and wheel. The luffing mechanism is only equipped on the jib crane. When the jib is raised, the amplitude decreases, while the amplitude increases when the jib is pitched. There are two kinds of luffing mechanism: balanced luffing and unbalanced luffing.

  The slewing mechanism is used for turning the boom, which is composed of a driving device and a slewing supporting device. Metal structure is the skeleton of the crane, the main load-bearing components such as bridge frame, boom and portal frame can be box structure or truss structure, can also be web structure, and some can be used as beam support.
 

  Boom design of cantilever crane

  The main girder of a cantilever crane is designed according to three-dimensional prestressing. The base plate is 6m wide and the wing plate is 2.5m wide. Longitudinal prestressing is composed of 12 j15.24 and 9 j15.24 steel hinges with symmetrical tension at both ends; transverse prestressing is composed of 2 j15.24 steel hinges with single-end tension; vertical prestressing is made of 32mm high-strength finish-rolled thick steel bars. The standard strength Ryb = 1860 MPa of cantilever suspension steel hinge line is OVM type anchorage, and the pipe is designed to be holed according to metal bellows; the standard strength Ryb = 785 MPa of coarse steel bar is adopted YGM type anchorage.

  A bridge length 120m, wide 12M, is a prestressed concrete continuous T type steel bridge. The main girder adopts single box and single room variable height concrete box section. The height of the girder at the main pier is 4.2 m and the height of the girder at the middle of the span is 2.1 M. The upper and lower edges of the floor are changed by two parabolas. The technology of the part is SL6400A light bus rear door outer panel. The structure size is large. The rear license plate lamp is fixed on the inclined plane of the middle part with three 8mm and two 30mm holes. The manual drilling method has been used for several years, which consumes a lot of manpower.

  In the past, short sleepers were laid across the chord bar of the steel beam to nail the rails, and each time the crane moved, it had to be disassembled and transported one by one. In this way, even if the upper chord is partly covered with scaffolding, it is still very unsafe, labor intensive and time-consuming. Each station (8m) must be moved by a workshift of about 8/hour to complete, accounting for 1/6-1/5 of the beam erection time (60-80m span) of the bridge.

  The cantilever crane sets the column vertically on the front cover of the press through the bolt, the top of the column is a cylindrical section, the two bearings are spaced on the cylindrical section of the column, one end of the cantilever with sliding groove is vertically equipped with a sleeve, the sleeve sleeve sleeve sleeve sleeve sleeve on the two bearings and interference fit, the pulley is arranged in the sliding groove of the cantilever and moves along the sliding groove, and the hand-pulling hoist is arranged on the cylindrical Lower end of chute.
 

  Characteristics of cantilever cantilever crane

  Characteristics of cantilever crane with wall and column type

  D-MOS movable pillar cantilever crane (500 kg) with complete supply range (including full set of electrical devices) is an ideal choice for frequently changing workplaces because it is easy to adapt to new requirements and can be quickly rearranged according to workplaces. Case D-MOS cantilever crane is especially suitable for maintenance or needs constant change.

  KBK pillar cantilever crane (to 1000kg) KBK pillar type cantilever crane is an independent and ideal workstation crane. KBK pillar cantilever crane has light deadweight, heavy lifting weight, long cantilever and small floor area. It can be fixed with heavy anchor bolts or embedded anchor bolts. KBK column type cantilever crane low clearance design low clearance design of the cantilever crane than the standard design of its own height is 290mm lower, therefore, for the space is small, but the lifting height requirements are greater.

  KBK double cantilever vertical column cantilever crane (to 1000kg) is more efficient than single cantilever vertical column cantilever crane. The installation area of double cantilever vertical column cantilever crane is the same. There are four different double cantilever combination schemes available. D-JB column type H/I steel cantilever crane (up to 1000kg) is characterized by greater load and longer cantilever service area. Low clearance cantilever crane can provide greater lifting height, it can also provide electric cantilever rotation function to facilitate operation.

  KBK wall-type cantilever crane (to 1000kg) because KBK wall-type cantilever crane is installed on supporting concrete walls, columns or other load-bearing components, so its decisive advantage is to save space on the ground columns, it is easy to install, ready-made standardized support saves a lot of complex calibration work, KBK wall-type cantilever crane applicable The load range can reach 1000kg.. The low clearance design of the cantilever crane is 290 mm lower than the standard design itself.
 

  Five conditions for electric hoist to stop operation

  If the electric hoist meets the following five situations, it needs to stop operation:

  1. It is possible to slip if the binding and suspension are not firm or unbalanced, and there is no padding between the corner of the heavy object and the wire rope.

  2. Structures or components have defects or damages that affect safety work, such as failure of brake safety device, damage of hook nut anti-loosening device, damage of wire rope to scrap standards, etc.

  3. Overload or unclear weight of objects, such as lifting or pulling weight or unclear pulling force of buried objects, and inclined suspension;

  4. There are people or floating objects on hanging objects.

  5, the work site is dim, unable to see the venue, suspended objects and command signals.
 

  Automatic protection of electric chain hoist with overload and low load

  The use of limited switches can eliminate damage caused by overload and low load to electric chain hoist.

  1. Button control handle

  Light weight button control has rainproof function and responsive.

  2, wear resistant load pulley

  Load pulley is made of alloy steel, and through professional heat treatment to wear resistance and smooth fit with the chain. The new chain design guide provides guidance for smoothly embedding the chain into the pulley.

  3. Low voltage of operation handle.

  The standard link hoist operating handle voltage is 24V-36V low voltage control, low voltage can effectively protect the operator from electric shock injury. 24V-36V is also the mandatory requirement of AQSIQ for special lifting equipment. )

  4. Hoisting height to the limit.

  The structural design of the chain hoist can achieve a high lifting height.

  5, operation mode

  The working mode of electric hoist is divided into single-speed or double-speed lifting, suspension hook or running car with manual or electric, two-way or multi-direction operation.
 

  Safe operation of electric hoist

  Safety operation specification of electric hoist in use, including the detection before use, some matters needing attention in use, and a series of processes after work.

  1. Before lifting, the mechanical part of the equipment should be checked, the wire rope, hook and limiter should be in good condition, the electrical part should be checked without leakage, and the grounding device should be in good condition. Each time lifting heavy objects, 10 cm off the ground should be suspended to check the braking situation, to confirm the integrity of the work before proceeding. Rain shelter should be installed in open air operations.

  2. Do not overload the lifting, do not hold the hand between the rope and the object when lifting, and strictly prevent collision when the lifting object rises.

  3, hoisting objects should be strapped firmly and weighed. Lifting walking, the weight off the ground should not be too high, forbid heavy objects from the head over, the work space should not be heavy objects suspended in the air.

  4. Electric hoist in the process of lifting odor, high temperature should be immediately stopped to check, find out the reason, after treatment can continue to work.

  5. The electric hoist wire rope should be winded neatly on the drum. When the hook is placed in a low position, the wire rope on the drum should not be less than three turns.

  6. Start with suspended cable electrical switch, insulation must be good, sliding must be free, and correct operation of the button and attention to people standing position.

  7. In the course of hoisting, when the heavy object slips due to the fault, emergency measures must be taken to drop the heavy object to the unmanned place.

  8, hoisting heavy objects must be vertical lifting, no heavy load is allowed, and the weight of lifting objects is not clear.

  9, after the work is finished, the electric hoist should be stopped at the designated position, the hook will be raised, and the power will be cut off.
 

  Classification of motor grade of electric hoist

  1. Continuous working system: running time under constant load is enough to achieve thermal stability.

  2. Short-term operating system: running at a given time under a constant load, the time is not enough to achieve thermal stability, and then stop running enough time, so that the motor is cooled again to the temperature difference between the cooling medium within 2K.

  3. Intermittent Cycle Working System: Running in a series of the same working cycles, each cycle including a constant load running time and a period of interruption shutdown time. The starting current of each cycle in this system does not significantly affect the temperature rise.

  4. Including the start-up intermittent cycle: running in a series of the same cycle, each cycle includes a period of start-up time which has a significant impact on temperature rise, a period of constant load operation time and a period of off-energy shutdown time.

  5. Including intermittent cycle operation of electric brake: running in a series of the same cycle, each cycle includes a period of start-up time, a period of constant load operation time, a period of rapid electric brake time and a period of off-energy stop time.

  6. Continuous cycle operation: running in a series of the same working cycles, each cycle includes a constant load running time and a period of no-load running time, but the uninterrupted shutdown time.

  7. Continuous cycle operation including electric braking: running in a series of the same working cycles, each cycle including a period of start-up time, a period of constant load operation time and a period of fast electric braking time, but no interruption of the shutdown time.

  8. Continuous cycle operating system including variable speed variable load: running in a series of same working cycles, each cycle including a period of constant load operating time at a predetermined speed, and a period or several other periods of constant load operating time at different speeds, but without interruption of energy shutdown time.

  9. Non-periodic variation of load and speed: Non-periodic variation of load and speed within the allowable range. This system includes frequent overloads, which can exceed the full load.
 

  Twelve points for safety operation of wire rope electric hoist

  The cautions for using wire rope electric hoists are as follows:

  1. Do not hoist objects with wire rope electric hoist that exceed the rated load. The rated load is marked on the hook nameplate.

  2. It is forbidden to take passengers on lifting objects. Electric hoists should not be used as lifting mechanisms for elevators to carry people.

  3. There should not be any person or important equipment and equipment under the lifting objects.

  4. Hoisting objects and hooks cannot be lifted under swing condition.

  5, please move the gourd up to the top of the object and hang up again.

  6, the limit device is not allowed to be used as a travel switch.

  7. No objects or buried objects connected to the ground should be hoisted.

  8, please do not over operate the wire rope electric hoist.

  9, do not use flashlight door line to pull other objects.

  10, before the maintenance inspection, we must cut off the power supply.

  11, maintenance and inspection work must be carried out under no load condition.

  12, please confirm whether the wedge is reliable and reliable before use.
 

  Safe operation of electric hoist

  Safety operation specification of electric hoist in use, including the detection before use, some matters needing attention in use, and a series of processes after work.

  1. Before lifting, the mechanical part of the equipment should be checked, the wire rope, hook and limiter should be in good condition, the electrical part should be checked without leakage, and the grounding device should be in good condition. Each time lifting heavy objects, 10 cm off the ground should be suspended to check the braking situation, to confirm the integrity of the work before proceeding. Rain shelter should be installed in open air operations.

  2. Do not overload the lifting, do not hold the hand between the rope and the object when lifting, and strictly prevent collision when the lifting object rises.

  3, hoisting objects should be strapped firmly and weighed. Lifting walking, the weight off the ground should not be too high, forbid heavy objects from the head over, the work space should not be heavy objects suspended in the air.

  4. Electric hoist in the process of lifting odor, high temperature should be immediately stopped to check, find out the reason, after treatment can continue to work.

  5. The electric hoist wire rope should be winded neatly on the drum. When the hook is placed in a low position, the wire rope on the drum should not be less than three turns.

  6. Start with suspended cable electrical switch, insulation must be good, sliding must be free, and correct operation of the button and attention to people standing position.

  7. In the course of hoisting, when the heavy object slips due to the fault, emergency measures must be taken to drop the heavy object to the unmanned place.

  8, hoisting heavy objects must be vertical lifting, no heavy load is allowed, and the weight of lifting objects is not clear.

  9, after the work is finished, the electric hoist should be stopped at the designated position, the hook will be raised, and the power will be cut off.
 

  Wall slewing crane

  Wall crane is called wall crane for short. It can be divided into manual and electric rotation. The large rotation angle is about 300 degrees.

  The large arm length 10m is attached to a sufficient strength support to support the wall crane.

  The fixing bracket of the wall type rotary jib crane is bolted to the fixing prop, which is convenient for disassembly and can be equipped with domestic wire rope electric hoist or chain electric hoist.

  The working area is circular.

  At present, the lifting capacity of the wall crane is less than 3 tons.
 

  Cantilever crane moment protection system

  In order to improve the accuracy of the input signal, a second-order low-pass filter is used to filter out the high-frequency noise in the front end of the torque protection system of the cantilever crane.

  A primary signal conditioning circuit is constructed at the end of the force sensor to solve the problem of long-distance transmission of the sensor signal in the work site. The execution part is isolated from the power supply and the system power to solve the system interference.

  The delta sigma type based on CS5505 and the SAR type A/D conversion circuit based on ADS7809 are compared. The results show that the former has simple circuit and obvious advantages in input impedance, noise suppression and price.
 

  The gnawing phenomenon of suspension cranes

  The concept, formation conditions and judgment of gnawing track are various. Sometimes there is only one wheel gnawing track. Sometimes there are several wheels gnawing at the same time. Some of the wheels gnawing at the same side of the track, and some of the wheels gnawing at the two sides respectively. The causes of rail gnawing are very complicated. It may be the track, wheel, bridge, or other factors. Therefore, specific problems should be analyzed in detail.

  Suspension cranes are orbiting, and the wheels are running on dedicated tracks. The crane rail is used to support all the weight of the crane to ensure normal and directional operation of the equipment.

  Therefore, the selection of suspended crane rail should meet the following technical requirements:

  (1) the rail top surface can withstand the extrusion force of the wheel.

  (2) the rail bottom has a certain width to reduce the pressure on the foundation.

  (3) there should be good wear resistance.

  During the operation of the crane, axial movement or axial skew often occurs due to various reasons. The wheel flange of the cart or trolley of the operating mechanism contacts the side of the track head, resulting in horizontal lateral force and serious friction, resulting in rapid wear and deformation of the wheel flange.

  At the same time, the side of the track also has serious wear. The crane is constrained by the flange and track in operation. When the crane is constrained, the wheel and rail contact state of the flange wheel. At this time, the wheel and rail have two contact points, point A on the tread is called load point, point B on the flange or excessive arc is called guide point. This kind of contact friction causes wheel rim friction and rail side friction, which is customarily called rail gnawing. Slight rail gnawing caused obvious wear marks on the flange and the side of the track; serious rail gnawing caused flange and the side of the track metal spalling or deformation.
 

  Working strength of cantilever crane (cantilever crane)

  Cantilever crane (cantilever crane) has a light working strength.

  The crane is composed of a column, a rotary arm drive device and an electric hoist. The lower end of the column is fixed on a concrete foundation by a anchor bolt, and the cantilever is driven to rotate by a cycloid pin wheel reducer. The electric hoist operates in a straight line from left to right on the cantilever I-beam and lifts the load.

  The swing arm of a crane is a hollow steel structure with light weight, large span, large lifting weight, and economy and durability. Built-in walking mechanism, using special engineering plastic wheel with rolling bearings, small friction, walking lightly; small structure size, especially conducive to improving the hook stroke. The machine usually has a huge structure and a more complex mechanism, the operation process is often several different directions of movement at the same time, the technical difficulty is greater.

  Heavy loads can be hoisted and loads vary. Some heavy objects weigh up to hundreds of tons, are large and irregular, and there are granular, hot melt and inflammable and explosive dangerous goods, so that the lifting process is complex and dangerous. It needs to operate in a larger scope and has larger activity space. Once the accident is caused, the area affected will be larger.

  Some lifting machines (only refer to construction lifts, etc.) need to carry personnel directly to do lifting movement, its reliability directly affects personal safety. Exposure to various parts of the activity, and often direct contact with the operator, there are many potential incidental risk factors. Operating environment is complex, such as involving enterprises, ports, sites and other places, involving high temperature, high pressure, inflammable and explosive and other environmental risk factors, threatening equipment and operators.

  Many people need to cooperate with each other in operation, which requires higher requirements for commanders, operators and lifting workers. When crane is working, overload protection device is a safety device which can protect overload operation. It includes lifting limiter and torque limiter. The main difference between them is whether the crane has dynamic measurement and control requirements of boom amplitude.
 

  Overloading protection device for cantilever crane

  The "Technical Specification for Safety of Overload Protection Devices for Cranes" (GB12602-90) stipulates the functional requirements, technical requirements, test methods, inspection rules and safety management measures for various types of crane overload protection devices.

  (1) function requirements: cantilever crane overload protection device can be divided into automatic stop type and comprehensive type. When the lifting mass exceeds the rated lifting weight, the former can automatically stop the crane to continue operation in an unsafe direction; while the latter can send out sound or light warning signals when the lifting mass reaches about 90% of the rated lifting weight; when the lifting mass exceeds the rated lifting weight, the crane should be able to stop moving in an unsafe direction. But both allow the crane to move in a safe direction. The device should also have the function of distinguishing the dynamic load effect caused by the lifting, braking and running of the crane when the crane is actually overloaded and when the crane is in normal operation.

  (2) Technical requirements: Standard for power supply devices and switch locking devices, anti-interference, strength margin, electronic components and components materials, construction, setting points, comprehensive errors, signals, display errors, operational errors, vibration and impact resistance, temperature adaptability, voltage fluctuation resistance, insulation resistance of power supply devices, Overload capacity, protection level, reliability and fatigue strength are specified.

  (3) Test methods: crane shall be tested before leaving factory for action error, vibration, impact, temperature, voltage fluctuation, anti-interference, insulation resistance, voltage withstand test, humidity and heat test, protection grade test, overload capacity test, alarm sound test, installation test, fatigue test and so on. Industrial operation test.
 

  Definition of hoisting machinery

  Lifting machinery refers to the mechanical and electrical equipment used for vertical lifting or vertical lifting and horizontal movement of heavy objects, its scope is stipulated as the rated lifting weight is greater than or equal to 0.5t; rated lifting weight is greater than or equal to 1t, and the lifting height is greater than or equal to 2m crane and load-bearing fixed electric hoist.
 

  Application of industrial weighing control technology in rotary arm crane machinery

  With the breakthrough of digital technology, especially the progress of electronic weighing control technology, the application of industrial weighing control technology in crane machinery has promoted the development of mechanization, automation, integration and intelligence.

  Due to the continuous expansion of industrial production scale and the increasing production efficiency, the large-scale, high-speed and specialized hoisting machinery has the characteristics of automation, intelligence and informatization. The application of modern industrial weighing control technology has made all kinds of hoisting machinery directly participate in loading, unloading, transportation, lifting, sorting, stacking, storage and even distribution of materials in the operating environment, and sometimes can directly measure, identify, track and manage materials.

  At present, the weighing devices used in hoisting machinery can be divided into two types according to their functions: electronic crane scale and special weighing device. There are many related explanations for the widely used electronic scale. The special weighing device mainly refers to the lifting weight limiter which has been widely used in hoisting machinery. The weighing sensor detects lifting weight, and the output signal is amplified by the amplifier. The amplified signal is sent to the weighing controller.

  The weighing instrument outputs the corresponding state control signal by comparing the weight signal with the three reference weight signal settings of "forecast warning", "delay warning and control" and "immediate warning and control". The setting values of the three benchmark weights are set at 90%, 105% and 130% of the rated load respectively. When the lifting load reaches 90% of the rated load, the weighing controller makes the buzzer sound intermittently. When the crane lifts, the temporary impact load will occur because of the accelerating force.

  In order to avoid the instantaneous false overload caused by the impact load during hoisting, the weighing controller has the function of time delay discrimination. At the end of the delay of 1-2 seconds, if the overload phenomenon still exists, the real overload is determined. The weighing instrument immediately outputs the signal to cut off the main hoisting circuit of the crane and the buzzer sounds long. The delay of overload signal is judged in the range of certain overload. If the overload is greater than 130% of the rated load, the weighing instrument outputs signals to cut off the main hoisting circuit of the crane, and at the same time gives an acoustooptic alarm, that is, an immediate alarm control. Because the output signal of the weighing controller only cuts off the main lifting circuit of the crane, it will not affect the action of the lifting circuit to descend and other mechanisms.
 

  Crane common sense

  I. General knowledge of hoisting machinery

  1. Hoisting machinery and cranes

  Lifting machinery is widely used in lifting, transportation, loading and unloading, installation and personnel transportation of various kinds of things in modern industrial production indispensable equipment.

  Crane is a kind of mechanical equipment that lifts, drops, or lifts and moves materials through hoisting hooks or other lifting devices in intermittent and repetitive working mode.

  2. Classification of lifting cylinders (see Table 1)

  3. Main parameters of hoisting machinery

  Rated lifting weight Gn, span S, amplitude L, lifting height H, operating speed V, lifting moment M, gauge k, base distance B, wheel pressure p, working level, etc.

  4, the reverse structure of crane structure.

  (1) Steel structure: main beam, end beam (beam), car frame, leg, lower beam, lifting arm, balance arm, column, door frame, tie rod, tower body, walkway and cab, etc.

  (2) transmission mechanism: lifting mechanism, operation mechanism, slewing mechanism, luffing mechanism and jacking mechanism.

  (3) Electrical system: handheld controller, master controller, conductive device, cable drum, resistance box, frequency converter and control cabinet, etc.

  (4) Main parts and components: crane, grab, lifting electromagnet, wire rope, ring chain, pulley, drum, brake, wheel and track, etc.

  5. Crane safety device

  Limiter, Limit Limiter, Buffer, Anchorage Straightening, Rail Clamp or Windproof Shoes, Safety Junk, Anti-Back Tilting Device, Lifting Limiter, Torque Limiter and Anti-Collision Device, etc.

Table 1. Classification of hoisting machinery
C
r
a
n
e
Light and small 
Lifting equipment
Hoist gourd
Such: electric hoist
Suspended sheep rail system
Monorail gourds
other
 
overhead type crane
Bridge crane
Such electric single beam crane. 
  Suspended single beam crane 
  Gourd double girder crane 
  Double girder bridge crane
Portal crane
Such:Gourd gantry crane 
  Single girder gantry crane 
  Double girder gantry crane 
  Tyre container gantry crane 
  Quayside container gantry crane
Half gantry crane
Such:Half gantry crane
Boom type crane
Cantilever crane
Such:pillar jib crane
Mobile crane
Such:Truck crane
  Tyre crane 
  Crawler crane
Tower crane
Such:Fixed tower crane
Portal crane
Such:Port gantry crane
oher
Such:Container overhead crane
Other lifting appliances
Cable crane
Such:stationary cable crane
Other lifting appliances
Construction elevator
Such:Construction elevator
Window cleaning machine
Such:Window cleaning machine
other
Such:Overhead working basket


  Two. Working characteristics and risk factors of lifting appliances

  1. Lifting machinery usually has a huge structure and a more complex mechanism, the operation process is often several different directions of movement at the same time, the technical difficulty is greater.

  2, heavy loads can be hoisted and loads are varied. Some heavy objects weigh up to hundreds of tons, are large and irregular, and there are granular, hot melt and inflammable and explosive dangerous goods, so that the lifting process is complex and dangerous.

  3. It needs to be operated in a large range, with a large space for activities. Once an accident occurs, the area affected is also large.

  4. Some lifting machines (only refer to construction lifts, etc.) need to carry personnel directly to do lifting movement, its reliability directly affects personal safety.

  5. There are many exposed parts of the activity, and they are often in direct contact with the workers, potentially many incidental risk factors.

  6. Complex operating environment, such as involving enterprises, ports, sites and other places, involving high temperature, high pressure, inflammable and explosive and other environmental risk factors, poses a threat to equipment and operators.

  7. Many people are often required to cooperate with each other in the operation, and the commander, operator and hoist are required to be higher.

  According to relevant statistics, the number of deaths caused by crane accidents in China accounts for about 15% of the total number of deaths caused by work in all industrial enterprises every year. In order to ensure the safe operation of lifting machinery, the state classifies it as a special equipment to be managed, many enterprises take good management of lifting equipment as a key link in safety production.
 

  Three. Safety requirements for hoisting machinery

  1, safety requirements for general requirements

  A. When the driver takes over, the brakes, cranes, wire ropes and safety devices shall be inspected, and when abnormal performance is found, the brakes shall be removed before operation.

  B, before you start, you must ring or alarm. When you approach people, you should also give intermittent bells or alarm.

  C and operation should be conducted according to the command signal, and the emergency stop signal should be executed immediately, no matter who sends it.

  D. When no one is confirmed on or around the crane, the main power supply can be closed. If the power circuit breaker is locked or marked, the main power supply can be closed only after the relevant personnel remove it.

  E, before closing the main power supply, all pulling handles should be placed in zero position.

  F. When a sudden power failure occurs at work, all the controller handles should be pulled back to zero, and the crane should be checked for normal operation before re-working.

  G, crane on the track and open operation, when the work is finished, the crane should be anchored. When the wind force is greater than 6, it should generally stop working and anchor the crane. For portal cranes and other cranes working along the coast, when the wind force is greater than 7, they should stop working and anchor the crane.

  H. When the driver carries on the maintenance, should cut off the main power supply and hang up the warning sign or lock, if has not eliminated the fault, should inform the successor driver.

  2, safe wiping requirements

  (1) drivers should not operate at any time in the following circumstances:

  A. Overload or unclear weight of objects, such as lifting or pulling weight or unclear pulling force of buried objects, and inclined cable-stayed suspension;

  B. Structures or components have defects or damages that affect safety work, such as brake safety failure, hook nut anti-loosening straight damage, wire rope damage to scrap standards, etc.

  C, binding and hanging are not firm or unbalanced, and may slip.

  D, there are people or floating objects on the suspended objects.

  E, the working place is dim, unable to see the venue, suspended objects and command signals.

  (2) when driving, the driver shall comply with the following requirements:

  A, no limit limit parking can be used.

  B, the brake of hoisting and luffing mechanism must not be adjusted under load.

  C, when lifting, it is not allowed to pass over the human body.

  D, crane should not be inspected and maintained during work.

  E. When the lifting weight approaching or reaching the rated lifting capacity, the brake should be checked before lifting, and the brake should be lifted smoothly with a small height and a short stroke.

  F. For a crane without a downward limit straight limiter, when the hook is in a low working position, the wire rope on the drum must keep the number of safety rings specified in the design.

  G. When the crane is working, the small distance between the boom, lifting accessories, wire rope, cable wind rope and heavy objects and the transmission line should not be less than the stipulations in Table 2.

Table two, small distance from transmission lines
Transmission line voltage V(kV)
〈1
1~35
>=60
4、distance(m)
15
3
0.01(V-50)+3

  H. Mobile crane should stop the airport smoothly according to the requirements of the instructions before working and strike the supporting legs firmly and reliably.

  I. For cranes without inverted braking performance, it is not allowed to brake by using a reversed truck except in special emergencies.

  (3) When hoisting the same weight with two or more cranes, the wire rope should be vertical, and the lifting and running of each crane should be kept in synchronization; the loads of each crane should not exceed their rated lifting capacity. If it fails to meet the above requirements, the rated lifting capacity should be reduced to 80%. It can also be used by the chief engineer to reduce the rated lifting capacity according to actual conditions. The chief engineer should be present at the time of lifting.

  (4) For a crane with two sets of lifting mechanisms, the main and auxiliary hooks shall not be operated simultaneously, except for a special crane which is allowed to be used at the same time in design.

  3. General safety requirements for lifting appliances

  A and command signals should be clear and conform to the regulations.

  When B or hanging, the angle between the hanging rope should be less than 120 degrees, so as to avoid the excessive force of the hanging rope.

  C, rope and chain should be lined with edges.

  D, when command objects are turned over, they should be weighed. The heart should change smoothly, and no action other than command intention should be generated.

  E, when entering the suspended weight, contact the driver and set up a direct supporting device.

  F, when many people bind and hang up, one person should be responsible for directing.

  4, safety inspection and apricot cycle requirements

  (1) the crane should be inspected according to the relevant standards in the following situations:

  A, crane with normal work is carried out every two years.

  B, overhaul, newly installed and renovated cranes before delivery;

  C, idle time more than one year crane before reusing;

  D. After storms, earthquakes and major accidents, cranes may damage strength, stiffness, stability of components and importance of mechanisms.

  (2) When the work is heavy and the environment is harsh, the regular inspection cycle shall not be less than once a month, and the regular inspection cycle shall not be less than once a year.

 

  Four, crane accident causes, prevention and treatment

  1. The causes of crane accidents mainly include human factors and equipment factors. Human factors are mainly due to managers or users'psychological reasons such as luck, saving trouble and reversal, which lead to irrational behavior. Material factors are mainly due to equipment not designed, manufactured, installed and maintained according to requirements. And maintenance, especially if the inspection is not carried out according to the requirements, with the "disease" operation, thereby burying the potential safety hazard.

  The main causes of crane accidents are:

  (a) Violation of safety operation rules, such as overloading or not confirming the weight of lifting articles, cable-stayed inclined crane, unreliable lifting down station, unreliable hanging hook and unqualified operators, etc.

  B, equipment safety protection device is not installed or failed. For example, the lifting height limiter, lifting weight limiter, torque limiter, hook anti-decoupling device, limit limit limiter, etc. are not installed or invalid, the equipment grounding or zero connection is unreliable, leakage protection is unreliable, etc.

  C, inspection and inspection were not carried out according to the requirements. If the regular inspection system (pre-shift inspection, weekly inspection and monthly inspection, etc.) is not established and implemented, the equipment will be "sick" if it is not submitted to the supervision and inspection institutions for acceptance inspection and periodic inspection as required.

  There is no safety guard or no warning sign for D and maintenance. If the adjacent equipment is not monitored, no warning signs will be installed on the ground power switch.

  E, the use of maintenance and other personnel do not wear protective labor protection products according to regulations.

  F or tower cranes are not installed or disassembled according to the prescribed procedures.

  G. The safe distance between the equipment and lifting articles and the electric wires in the working environment can not be guaranteed during the operation of truck crane.

  2. In view of the various causes of crane accidents, the user should cooperate closely with the manufacturing, installation and maintenance units, the crane machinery supervisory departments and the supervisory and inspection institutions, strengthen the management work, implement the various inspection systems, eliminate hidden safety hazards and minimize the possibility of accidents. The user must do at least the following work:

  A. Strengthen the safety ideological work conscientiously, from the safety staff to the operation, maintenance and inspection personnel should cultivate safety awareness, consciously avoid unsafe behavior;

  B, strictly enforce safety procedures, and eliminate illegal operation.

  C, formulate a sound inspection and inspection system and implement them strictly.

  D, training and assessment of operators.

  3. Handling of lifting injury accidents.

  The handling of crane injury accidents can generally be divided into five stages: on-site handling, investigation of accident details, analysis of accident causes, and settlement of accidents.

  1) After a lifting injury accident, the unit where the accident occurs must do everything possible to organize the rescue of the injured and state property, take effective measures to stop the spread of the accident, and carefully protect the scene of the accident. All objects, traces and conditions that may be related to the accident shall not be damaged artificially. If the injured need to be moved to rescue the injured Certain objects on the scene must be well marked, photographed and recorded in detail.

  2) While handling the scene, the unit shall immediately report the accident situation to the local safety supervision department and the relevant competent departments by telephone, telegram or other quick means.

  3) after analyzing the causes and responsibilities of the accident clearly, it should be dealt with seriously according to the relevant laws and regulations.

  (1) accidents involving leadership responsibilities should be investigated, inclu

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