Reasons and solutions for jitter of the lifting mechanism and engine stalling of truck cranes

Truck cranes play a crucial role in various construction and industrial settings, enabling the lifting and transportation of heavy loads. However, at times, issues can arise that affect their performance and safety. One such problem is the jitter of the lifting mechanism and engine stalling, which can pose significant challenges and potential risks. In this article, we will explore the reasons behind these issues and discuss possible solutions.

18m Truss Type Bridge Inspection Platform (4)

When lifting a heavy load, the lifting mechanism jitters. This is a concerning problem that can not only affect the efficiency of the operation but also pose a safety hazard. During heavy lifting operations, it is observed that the drum rotates intermittently and cannot work continuously, and there is obvious vibration. This jitter can be disconcerting for the operator and may lead to instability in the lifted load.
In an attempt to address this issue, increasing the engine throttle is often a first instinct. However, in this case, it is found that even when increasing the engine throttle, the fault remains. This indicates that the problem is not simply a matter of insufficient power. At the same time, there is also the phenomenon of engine stalling. Engine stalling can be extremely dangerous, especially when lifting a heavy load. It can lead to a sudden loss of power and potentially cause the load to drop, endangering the safety of personnel and property.

45M HOWO Ladder Lift Truck

To diagnose the problem, a series of measurements and inspections are carried out. Firstly, the control oil pressure entering the brake piston before the throttle valve in the hydraulic oil circuit of the lifting mechanism is measured. It is found to be normal (1.5 – 1.8 MPa). This indicates that the problem is not related to the initial stage of the hydraulic system.
Next, the possibility of the lifting balance valve being stuck by dirt is considered. The lifting balance valve plays an important role in ensuring the smooth operation of the lifting mechanism. If it is stuck by dirt, it can disrupt the flow of hydraulic oil and cause problems. However, after careful inspection, this possibility is ruled out.

ISUZU GIGA Truck with 10T XCMG Crane

Finally, it is judged that the one-way throttle valve in the brake oil circuit may be blocked. The one-way throttle valve is designed to control the flow of hydraulic oil to the brake piston. If it is blocked, it can affect the operation of the brake and lead to problems with the lifting mechanism. After disassembling and inspecting the one-way throttle valve, it is found that the 0.6mm throttle hole on the valve core has been blocked by dirt. This blockage causes the pressure oil entering the brake piston after the throttle valve to be throttled, and the pressure is lower than 1.8 MPa. As a result, the brake piston cannot be fully opened, which leads to the jitter of the lifting mechanism and the engine stalling.
Once the problem is identified, the solution is relatively straightforward. The dirt blocking the throttle hole is removed. After this is done, the lifting mechanism works normally again. This shows the importance of regular maintenance and inspection of truck cranes. Dirt and debris can accumulate in the hydraulic system over time, leading to various problems. By regularly cleaning and maintaining the system, such issues can be prevented.

Huashen D912 12-ton 9-meter truck crane

For example, imagine a construction site where a truck crane is in use. If the lifting mechanism starts to jitter and the engine stalls, it can cause significant delays in the project and pose a safety risk to the workers. By quickly diagnosing the problem and removing the dirt from the one-way throttle valve, the crane can be back in operation, minimizing downtime and ensuring the safety of the construction site.
In conclusion, the jitter of the lifting mechanism and engine stalling of truck cranes can be caused by a blockage in the one-way throttle valve. By carefully measuring and inspecting the hydraulic system, the problem can be identified and resolved. Regular maintenance and inspection of truck cranes are essential to prevent such issues from occurring and ensure the safe and efficient operation of these important pieces of equipment.

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