How to choose the right crane sheave block and the problems you are likely to encounter
According to the function, crane sheave block can be roughly divided into fixed pulley, dynamic pulley, pulley set, guide pulley, etc.. Baoxin will answer your questions.
1. choose crane sheave block according to the demand
Dynamic pulley can only play the role of force saving, can not change the direction of the force; fixed pulley, although it can change the direction of the force, but can not play the role of force saving. In the process of crane operation, if you want to change the direction of movement of the wire rope and want to achieve the purpose of force saving, it is necessary to connect the fixed pulley and dynamic pulley together to form a pulley block to meet the operational needs.
2. According to the material selection crane sheave block
According to the material, crane sheave block can be divided into cast steel pulley block, cast iron pulley block, nylon pulley block, hot-rolled pulley block and aluminum alloy pulley block.
Cranes with small lifting capacity and low working level can choose cast iron sheave block, nylon sheave block and aluminum sheave block; cranes with large lifting capacity and high working level can choose cast steel sheave block and hot-rolled sheave block; in addition, explosion-proof cranes can choose aluminum sheave block or nylon sheave block.
crane sheave block problems easily encountered in the later stages of work.
Crane sheave block in the crane is an important component of the crane lifting, generally composed of rolling bearings, pulleys, pulley shafts, rolling bearing spacer. Problems with the sheave block will directly affect the normal construction.
1. Crane overload
Lifting heavy objects overload, directly causing the lifting pulley parts shaft bearing force increases, close to or beyond the force range, which is the most direct cause of bearing damage.
Solution: Increase the overload limiting device. According to the load table to calculate the maximum bearing force, when the bearing bearing load force equal to the rated force to issue an alarm, prompting the operator.
2. Pulley quality problems
Wire rope directly wrapped around the crane lifting pulley, the weight of the object is directly transferred to the bearing through the wire rope and pulley. Therefore, the bearing is easily damaged.
Solution: change the structure of the pulley, increase the thickness of the pulley and replace the bearing.
3. The heavy object is not stable in the air during construction, and there is shaking
The shaking will lead to uneven bearing force on the shaft, and if the pulley is still rotating at this time, the bearing retaining ring will bear significantly more force, and the bearing will be easily damaged under such circumstances.
Solution: Construct in accordance with the requirements of the equipment instruction manual, strictly prohibit overloading, keep the weight stable during the process of lifting and descending, and avoid uneven bearing force and axial force increase due to the shaking of the weight.
4. Design deviation
If you choose a small safety factor or a large error in the calculation of the load, the bearing capacity can not meet the actual work needs. In addition, unfamiliar with the working conditions, will also cause the selected bearings do not meet the actual working needs. If the bearings selected are small in all parameters, the bearings will also be damaged prematurely.
Solution: Strictly control the quality of the pulley, improve the production process of the pulley and strictly check the inspection procedure of the pulley in the factory, and control the center of the rope groove of the pulley and the flatness of the center of the pulley to meet the design requirements.
Construction machinery construction is generally about timeliness, time is benefit, crane as a special mechanical equipment, in order to construction process continuous uninterrupted, must be analyzed for the above situation, to solve the problem of premature damage to crane sheave block.