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Home > new > Safety and management of tower cranes(two)

Safety and management of tower cranes(two)


2011/12/4 9:38:42


5 safety devices

In order to ensure the normal tower crane and safe use of tower cranes in the mandatory requirements we must have the required installation of safety devices, are: lifting torque limiter, since the weight limiter, height limiter, amplitude limiter, rotation stopper, hook safety device, roll safety device, wind anemometer, rope off the tank, insurance, car anti-broken rope device, anti-car devices and buffers such as off-axis. These safety devices to ensure its integrity and sensitive and reliable. Damage found in the use of timely maintenance and replacement, shall be adjusted or lifted without permission, April 20, 2003, the city tower crane driver Guanyun a site without the torque limiter removed, resulting in overloaded tower crane standard operating section angle cracking, collapse of tower crane arm, fortunately found in time, there were no casualties. Another example is the July 16 construction companies in Beijing Nantong construction lead 2 death and three injuries a major tower crane overturning accident is due to illegal transfer high torque limiter overload caused by the operation of these lessons in blood can not but arouse our insurance for the safety of tower cranes devices are highly valued.

6 Stability

Height and the bottom of the tower crane supporting a larger size ratio, and the tower's high center of gravity, torque, frequent starting and braking, the impact force, in order to increase its stability, we will analyze the main tower crane tipping were the following: First, the overload. Different types of cranes lifting torque-based control is usually used when the work rate of increase or exceed the rated load weight, the weight of the overturning moment exceeds its steady torque, it may cause tower collapse. Second, the oblique hanging. Inclined lifting weights will increase its overturning moment, in the lifting point will have a horizontal component and vertical force, the points of support at the bottom of the tower crane will have an additional overturning moment, thereby reducing the stability factor, resulting in crane collapse. Third, the tower crane foundation injustice, lack of endurance, vertical error is too large will increase the overturning moment caused by the tower crane, tower crane stability to decrease. Therefore, we proceed from these key factors to strictly check the inspection checks, personal safety equipment to prevent major accidents.

7 Electrical Safety

Accordance with the "construction safety inspection standards" (JGJ59-99) requirements, a special crane switch box must meet the "one machine a gate a drain a box" requirements, leakage protection device trip should not exceed the rated operating current 30mA Rated operating time of not more than 0.1s. Driver's switchboard room shall not be exposed. Electrical cabinet should be intact, tightly closed, door locks complete electrical components inside the cabinet should be in good condition, the line clear, sensitive and reliable operation control agencies, the limit switches in good professional electrician to check regularly scheduled maintenance.

8 devices attached to the wall

When the tower crane exceeds its time to set up an independent high device attached to the wall, in order to increase the stability of the tower crane. Device attached to the wall in accordance with the requirements of tower crane erection instructions, attached to the wall above the wall spacing, and with a high degree of freedom can not be arbitrarily long, long attached to the wall to support the design and there should be additional calculations, checking for strength and stability. Attached to the frame to maintain the level of fixation and attachment bar at the same horizontal plane, and the strong connection between buildings, attached the following tower after the vertical attachment points is not greater than 2 / 1000, vertically above the attachment point is not greater than 3 / 1000. Connection point with the building to be elected in the concrete or concrete ring beam on the column. Or off the wall with bolts embedded parts and the building structure and effective connectivity. Some construction companies with expansion bolts instead of embedded parts, and replaced with a rope attached to the cable supporting the wind, these are very dangerous.

9 safe operation

The key is the management of tower cranes on the driver's management. Operator must be in good health, understand the mechanical structure and working principle, familiar with mechanical principles, maintenance rules, certificates. Driver must make the required maintenance work on the crane, a high degree of responsibility, seriously prepare to clean, lubricate, tighten, adjust, corrosion, etc., shall not drink and work, not sick or tired operations, crane machine operating in strict accordance with procedures and crane "10 are not allowed, ten do not hang" operation, not illegal operations, barbaric operation, the right to refuse illegal command, the job must have adequate lighting at night. Safe use of tower crane usually lies in the operator's skill level and sense of responsibility, inspection, maintenance and key in the mechanical and electrical maintenance worker. We must firmly establish the people-oriented thinking.

10 safety inspection

Before and after the tower crane installation and daily use should check it. Every weld metal structure shall not crack, no plastic deformation of metal structures, bolt, pin quality to meet the requirements, the only retreat, locking measures, bolt preload to arrange a regular basis, well maintained wire rope lubricant, not exceeding the number of broken wires , must not be allowed off the unit, not plastic deformation, Shengka connector standard, gearbox and fuel tank may not leak, the hydraulic system pressure is normal, brake and limit insurance, sensitive and reliable, well-lubricated transmission, complete and reliable safety device , well-insulated electrical control circuit. Particular, to supervise the tower crane driver, maintenance, electrical and mechanical maintenance man should always be checked, to focus on checking the wire rope, hook, various transmission parts, wearing parts such as limit safety device, identify problems dealt with immediately, so who was scheduled time, measures, and strictly prevent mechanical sick job.

11 exit mechanism

The obsolete models must resolutely prohibit the use, dilapidated tower crane in the identification of the load after the repair to limit the use of tower crane for the life there is no uniform standard, different opinions, different parts of the provisions of the concentration being in some production manufacturers in order to meet the requirements of the construction business, expanding sales, dominate the market, will be independent of height increase, the lifting tower crane arm extended to increase the coverage, so that will definitely lower the tower crane stability, reduce the rated lifting capacity, increase insecurity of factors. There are some unauthorized modification of the tower crane and private in the group with the tower crane, tower crane's this part of the longer, second-hand purchase cheap, do not want to put in more capital maintenance, so frequent failures, which should cause us great attention, we should be realistic, according to local conditions, to seek the views of all parties in a wide range based on the introduction of the relevant supporting policies to address this problem.

Conclusion

Through the strengthening of the tower above aspects of safety management, can effectively prevent the process of tower crane use a variety of incidents, to play the purpose of preventive measures. Practice has proved that as long as the various construction companies, manufacturers, construction administrative departments, tower crane testing organizations can do according to all aspects of the above, strengthen the tower crane safety administration, we can effectively control the major tower crane accidents.