Precautions before CNS crane hoisting operations:
1. Check that the steel wire rope and connection parts comply with the regulations.
2. Check that there are numerous stability protection devices and indicating instruments.
Before starting the oil pump, let the engine run at low speed for a period of time first.
4. Sufficient fuel, lubricating oil, hydraulic oil and cooling water should be added.
5. Pay attention to whether the foundation is soft. If it is relatively soft, it is necessary to pad the outriggers with load-bearing wooden boards or soil blocks.
6. Check if the hydraulic system is functioning properly.
7. Adjust the outriggers. It is necessary to fully extend the outriggers in the prescribed sequence to ensure the lifting is in a water state. Adjust the machine body so that the inclination of the slewing bearing surface does not exceed 1/1000 when there is no load (with the level bubble centered).
8. The outriggers should not be close to the square sections of the foundation.
9. Thoroughly inspect the ground conditions at the workplace. The ground at the workplace needs to be capable of keeping the crane in a horizontal position and sufficient to withstand the torque acting on the outriggers.
10. Check the tire pressure and ensure that all connecting parts are not loose.
11. Confirm the weight and center of gravity of the lifted object to prevent overloading.
12. According to the lifting operation curve, determine the workbench radius and the rated total lifting capacity, that is, adjust the boom length and boom Angle to ensure stable operation.
13. Underground buried objects should be inspected in advance, and stable signs should be placed near the buried objects to draw attention.
14. The lifting height should be confirmed. According to the model of the crane, there are specific regulations on the height to which the hook can be lifted. The height of the steel wire rope used for binding the rope loop and the margin required for lifting the goods should be estimated in advance; otherwise, the goods cannot be lifted to the required height. A gap should be left between the bottom surface of the arm and the goods being called.
When in use, the Marine crane can be installed on the hull of the vessel or the storage ship as a gantry crane. The entire equipment can adopt two forms: rack luffing and wire rope luffing. It can luffing under load and perform displacement. Marine cranes can perform loading and unloading operations between ships on the shore or between ships. The center of gravity of the turntable of this machine is relatively low, with good stability and flexible operation. When in use, we often apply it more and more in some heavy industries such as ports, freight yards and docks.
Under normal circumstances, a crane is mainly composed of two parts: the power unit and the frame. The working speed of the crane is also closely related to its working principle. The main principle of a crane lies in the composition and operation of its power unit. The power unit is composed of an electric motor, a reducer, a clutch, a brake, a rope drum and a steel wire rope, etc. The motor of the crane is mainly a single-phase capacitor motor with magnetic connection. During the design process, there will be a braking mechanism when power is cut off. A thermal switch is also installed in the motor, which can prevent the motor from overheating and burning out to a certain extent. The reducer is divided into two-stage gear reduction, so it is connected to the motor. The clutch, brake and fly cylinder are integrated as one. However, when the clutch is disengaged, it can achieve rapid descent. Operating the brake can control the descent speed to avoid impact.
After long-term use, the components of the hoist will also experience more or less faults as the frequency of use increases. When the rotary table of the equipment malfunctions, we need to learn how to disassemble it. The slewing bearing of the hoist is relatively heavy, with some weighing about 2 to 3 tons, making disassembly and assembly quite difficult.
Disassembly requirements for cranes:
1. Install the lifting tools, lift and remove the slewing bearing. To disassemble the slewing bearing, tools should be used, such as making lifting rings with three screw rods, installing the threads of the lifting rings into the lifting threads of the slewing bearing, and lifting the rotary table at three equal positions with steel wire ropes or chains.
2. Clean the mating surfaces of the frame and the slewing bearing, and apply lubricating oil on the mating surfaces.
3. Secure the inner ring of the slewing bearing with fixing bolts.
4. Use a crane to lift the slewing bearing of the hoisting machine, and make marks on the frame and the inner ring of the slewing bearing. To correctly rotate the soft area of the inner circle, it is necessary to align the marking accurately.
Disassembling and assembling the rotary table of the hoisting machine is an important task. When in use, it is mainly because the bearing force-bearing surfaces of the slewing bearing are all made by high-frequency induction hardening. Around the entire high-frequency induction hardening area, there are unquenched parts distributed at the connection points, generally 50-80mm long, which are called soft band layers. This part should be placed in the area with less force on the entire vehicle during installation. Therefore, special marks should be made during repairs. If a new one is to be replaced, special attention should also be paid to the force-bearing part of this soft belt layer.
