Equipment safety of tower crane
Some use units over profit, not pay attention to safety, small horse cart, overloading seriously, tower crane accident is one of the main source of high incidence. Some manufacturers in order to meet the construction requirements of the enterprise, expand sales, to occupy the market, will be independent of height increase, the boom will be lengthened to increase the tower coverage, this is bound to reduce the stability of tower crane, reduce the rated lifting weight, increased insecurity. There are some private and unauthorized modification of the tower crane tower crane in the assembly, this part of the tower crane for a long time in the second-hand purchase price is cheap, not willing to invest in maintenance, and frequent failure, which should arouse our attention, we should seek truth from facts, according to local conditions, to solicit the views of all parties on the basis of the introduction of relevant the supporting policies to solve this problem. By strengthening the safety management of several aspects of tower crane, it can effectively prevent all kinds of accidents in the process of tower crane use, and play a preventive role. Practice shows that as long as the construction enterprises, factories, construction administrative departments, in accordance with the tower crane detection institutions can each link to do, to strengthen the safety management of the tower crane, can effectively control the incidence of major accident of crane.
Safe distance tower and transmission line is not up to the requirements of the tower frame door frame to design, erection principle to power erection, do not use metal materials, bamboo and other materials can be used. The distance between a bamboo pole and a power line shall not be less than 1m, and a certain degree of stability shall be taken to prevent the wind from blowing. The tower crane height and bottom bearing size ratio is large, and the center of gravity of the tower body, high torque, braking frequency, impact force, in order to increase its stability, we will analysis the main causes of the tilting of the tower crane has the following:Overloading. Different types of cranes usually adopts the lifting torque based control, when the amplitude exceeds the rated load weight increase or the corresponding weights, the overturning moment more than stable moment of it, it may cause the collapse of the tower crane.Two, inclined hanging. Slant weights will increase its overturning moment, the lifting point will produce horizontal force and vertical force on the crane, bottom supporting point will produce an additional overturning moment, and the stability coefficient is reduced, resulting in tower crane collapse.Three, the tower crane foundation is uneven, the ground endurance is insufficient, the perpendicularity error is too big, also can cause the tower crane to overturn the moment to increase, causes the tower crane stability to reduce. Therefore, we should proceed from these key factors to strictly check, check and check, and prevent major equipment personal safety accidents. State explicitly eliminated the model should resolutely prohibit the use of, in disrepair, tower crane in the identification of the repair, to limit the use of load, tower crane for the use of fixed number of years there is no uniform standards, opinions vary, different places have different provisions.
The boom of a tower crane is divided into two types: horizontal and compressed arms. When the movable arm is horizontal, the carrier car runs along the horizontal arm with variable amplitude and amplitude, and the movable arm is longer, but the boom has a larger deadweight. The arm for the strut type when the tractor boom luffing mechanism pitch amplitude, amplitude motion than horizontal smooth, but its relatively small weight.The weight of a tower crane varies with its amplitude. The product of the weight and the amplitude is called the load torque, which is the main technical parameter of the crane. Through the rotary mechanism and slewing tower crane, lifting height, rotation and walking the inertial mass, so it needs to have good control performance, especially the lifting mechanism can fast, slow, heavy and light load installation fretting. In addition to the general use of resistance speed regulation, but also often use eddy current brake, FM, pole change, SCR and mechanical and electrical joint speed regulation. When the crane in the layout to drawing, especially in real estate development area, residential buildings, such as tower crane, but also to consider the safety distance of adjacent tower crane, two in horizontal and vertical direction to ensure the safe distance of not less than 2m, the adjacent tower crane tower crane and interference can not occur. Try to ensure that the tower crane in the wind is too large to be free of rotation. The safe distance between the rear arm of tower crane and adjacent buildings shall be no less than 50cm. The safe distance between tower crane and power line meets the requirement.
