What do you know about hydraulic locks for truck mounted cranes?

The truck mounted crane hydraulic lock, also known as compression protection and blocking valve, is used in mining, engineering, crane, port, and other types of machinery such as outriggers, telescopic automatic and other weight-bearing cylinders of cranes, road heading machines, loaders, and other hydraulic systems.

In these hydraulic systems, when the oil pump stops supplying oil or the reversing valve is in the middle position, the load cylinder is under variable force in two directions, and the pressure oil in the cylinder is easy to leak from the gap of the reversing valve. Therefore, the installation of a hydraulic lock between the reversing valve and the cylinder can play a pressure-holding role to prevent leakage and ensure the stability of the loading cylinder piston.

Many people often find that when using a truck mounted crane for construction work, the original drop-off legs have been punched and the vehicle is in a horizontal state. However, after a certain period, the vehicle will be slightly tilted. At this point the whole car is no longer in a horizontal status, with the crane in the safety of the hidden danger,serious cases may occur a major accident.

So, what are the specific causes of this phenomenon? And what can people do to solve this phenomenon?

According to the principle of the truck crane hydraulic system, there will be two failure points: one is the vertical cylinder, and the other is a hydraulic lock.If the cylinder is faulty and the internal seal is worn, replacing the seal will solve the problem. If the cylinder is internally damaged, the cylinder must be replaced.If it is a problem with the hydraulic lock, it needs to be disassembled and checked for impurities stuck in the main and cleaned. If it is a problem such as a strained valve stem then it must be replaced.

So how do we check whether it is the cylinder or the hydraulic lock that is the problem?

1. extend the horizontal vertical cylinder of the outrigger and turn off the engine.

2. face the hydraulic lock and remove the bottom left rodless chamber interface of the hydraulic lock.

3. check whether there is continuous hydraulic oil flowing out of the hydraulic lock interface, if so, it is a hydraulic lock problem, if not, it is a cylinder problem. When replacing the hydraulic lock take care that the vertical cylinder is not under pressure to avoid injury during disassembly.