20 Ton Crane Safety Technical Inspection

Crane Safety Technical Inspection
 

Safety technical inspection is the key to the management of hoisting equipment. The use effect of hoisting machinery depends largely on the quality of safety technical inspection, daily maintenance and management during the use of hoisting machinery.
 

It is of great significance to do a good job in the safety technical inspection of the 20 ton bridge crane, and to carry out timely maintenance and maintenance according to the actual situation of the inspection, which is of great significance to prolong the service life of the equipment, improve the intact rate and utilization rate of the equipment, eliminate hidden dangers of accidents, and ensure safe production.
 

 

1. Inspection of the operating environment
 

Although the operating environment does not belong to the scope of the crane itself, it is directly related to the safe operation of the crane, so it is also an indispensable content for the safety inspection of the crane.
 

The first inspection is to check whether there are power lines (especially high-voltage lines) in the operating range of the crane, and the crane should keep a sufficient safe distance from it when it is running. Otherwise, corresponding measures should be taken to limit the operating range of the crane.
 

Second, check whether the surrounding buildings, temporary facilities, etc. prevent the normal operation of the crane, and whether the boom, counterweight and other parts will collide with them, especially when the gantry crane track is extended or the fixed crane is raised and displaced. Special attention should be paid to inspection.
 

For truck cranes, it is also necessary to check whether there are enough outrigger positions, whether there are holes in the ground, and the size of the ground bearing capacity.
 

Check the crane rails, rail stoppers, anti-collision devices at both ends of the rails, rail gnawing conditions, and rail temperature gaps in detail.
 

 

2. Inspection of the walking part
 

Mainly check the walking wheel tread, the open gears, couplings, the foundation bolts of the transmission and the oil hole of the walking wheel shaft, etc., such as the hardness of the surface of the walking wheel tread is not good;
 

Blocky peelings can be seen during the inspection, and each open gear and coupling should be equipped with a protective cover;
 

If the basic bolts of the transmission are loose, they should be tightened in time;
 

Keep the oil hole of the walking wheel axle unobstructed.
 

3. Inspection of metal structures
 

Attention must be paid to plastic deformation of metallic structures.
 

The camber of the main girder is the key part of the structural inspection of the crane, to avoid the disappearance of the camber of the main girder of the crane or even the downward deflection due to factors such as overloading and heat radiation.
 

In addition, key inspections should be made on whether the boom is bent or twisted; whether the lug plate at the root of the boom and balance arm is cracked, whether the weld between the main girder web plate of the bridge crane and the lower cover plate is cracked, etc. .
 

The inspection of the main structural connecting bolts of important parts such as the crane jib, the tower body of the tower crane, the slewing center bearing seat of the portal crane, and the base of the crawler crane, because the bolts in the above parts are frequently subjected to tensile stress, shear force and torsion Combined action such as force, if the situation of breaking from the root occurs, the consequences will be very serious.
 

 

4. Inspection of various mechanisms and parts
 

① Brake The brake is an important part of the crane, which directly affects the accuracy and reliability of the movement of each mechanism. Therefore, it is necessary to carefully check the brakes of the hoisting mechanism and the luffing mechanism, and observe the opening of the brake shoe and the wear of the friction elements. .
 

For band brakes, pay attention to check whether the steel backing of the brake band has cracks, whether the transmission of the brake is flexible, whether the brake frame is intact, and whether the elasticity of the main spring and auxiliary spring meets the requirements.
 

② Reducer Check whether there is oil leakage in the reducer, and whether there is any abnormal sound in the box during operation.
 

Abnormal noise is generally caused by bearing problems or excessive gear meshing backlash, serious tooth surface wear and other reasons.
 

③ Check the steel wire rope and pulleys for broken wires, wear, kinks and corrosion, etc., mark the positions where the wear and broken wires are serious but have not exceeded the standard, so as to focus on re-inspection; check the safety limit of the steel wire rope in the drum. Whether the positioner is valid and whether the wire rope pressure plate on the reel is pressed tightly.
 

The inspection points for the pulley are whether the wear of the bottom of the groove exceeds the standard, and whether there are cracks in the cast iron pulley. The balance wheel of the pulley block of the pitching mechanism is easy to be overlooked. Before installation, the flexibility of its rotation must be checked. If the balance wheel does not rotate flexibly, the length and tension of the left and right steel wire ropes during installation cannot be self-adjusted through the balance wheel, which will increase at high altitude. Adjust the difficulty and risk of operation of the steel wire rope.
 

④ Coupling Check whether each coupling is loose or even "rolled key".
 

Focus on checking whether the elastic rubber ring of the elastic pin coupling is abnormally worn, and pay special attention to the wear of the gear and ring gear of the toothed coupling.
 

In the case of poor installation accuracy and large offset between the two shafts, the entire ring gear will soon wear out. If this situation occurs in the hoisting mechanism, serious accidents are likely to occur.
 

 

5. Inspection of the hydraulic system The hydraulic transmission system is generally used for the lifting, slewing, luffing and outrigger telescopic actions of the truck-mounted rubber-tyred crane.
 

It is necessary to check whether the hydraulic cylinder of the telescopic arm can maintain the extended length of the boom for a long time, and whether the hydraulic cylinder is leaking; check whether the luffing cylinder and the outrigger cylinder are leaking, and whether the sinking and retracting amount meet the requirements under the rated load , whether the outrigger has "soft leg" phenomenon;
 

Check whether the operation of each hydraulic pump, valve and hydraulic lock is normal, whether the action is sensitive and reliable, whether there is abnormal vibration and noise, whether the performance of the seal is good, whether there is internal leakage or leakage of hydraulic oil;
 

Check the hydraulic oil for deterioration and contamination;
 

Whether the liquid level of the fuel tank meets the regulations, and whether there is any leakage in the high-pressure pipes and joints.
 

6. Crane electrical inspection
 

Cranes operate under shock, vibration and swing conditions, and electrical equipment is prone to failure, especially in high-temperature, dusty, and humid environments, where failures are more likely to cause accidents. Therefore, attention should be paid to the safety inspection of the electrical part of the crane.
 

The electrical system must pay attention to whether the insulation resistance of the motor is within the normal range, whether there is abnormal noise during operation, and whether the temperature rise is normal;
 

When shutting down, check whether there are obvious cracks, wear, looseness, and carbon powder attached to the trickle ring, brushes, and wire joints; Whether the contact of the block is good;
 

Check whether the electrical components and the switch shell of the control system are damaged, whether the pressure of the contact part is appropriate when closing, and whether the capacity of the fuse meets the requirements;
 

Whether the main contacts and auxiliary contacts of the contactor are singeing, whether the pressure between the contacts is sufficient when contacting, and whether the contacts are completely disengaged;
 

Whether there is any attachment on the suction surface of the static and dynamic iron core of the contactor, whether there is any abnormal sound when the suction is closed, and whether the arc extinguishing cover is intact;
 

And whether the relays on the power distribution cabinet are working normally, whether the binding posts and wiring screws are fastened well, whether the action direction of the controllers in the cab is correct, and whether there is zero protection. In particular, check whether there is an emergency switch on the console. Electric switch, and confirm whether the power can be effectively cut off in case of emergency;
 

Check the sensitivity and reliability of the torque limiter, overload limiter and each travel protection device.
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