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

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

In these hydraulic systems, when the oil pump ceases providing oil or the reversing valve is in the center position, the load cylinder is under changeable force in two directions, and the pressure oil in the cylinder is not hard to ooze out from the gap of the reversing valve.

Therefore, the fitting of a hydraulic lock between the reversing valve and the cylinder can act as a pressure-holding role to stop oozing and ensure the steadiness of the loading cylinder piston.

Many people often find that when making use of a truck mounted crane for building work, the vehicle is in a horizontal state, and the original drop-off legs have been punched. However, after a specific period, the vehicle will be a bit slanted. At this moment, the whole car is not in a horizontal status, with the crane in the protection of the hidden danger, serious cases may cause a major accident.

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

According to the concept 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 work out the issue.

If the cylinder is spoiled from the inside, then it must be replaced. If it’s an issue with the hydraulic lock, it requires to be dismantled and inspected for dirtiness stuck to be washed. And in cases such as a strained valve stem, then it must be restored.

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

●       Expand the horizontal and vertical cylinders of the outrigger and turn off the engine.

●       Face the hydraulic lock and get rid of the bottom left rodless chamber interface of the hydraulic lock.

●       Check if there's constant hydraulic oil oozing out of the hydraulic lock interface; if so, it is a hydraulic lock issue; if not, it is a cylinder error. When restoring the hydraulic lock, take care that the vertical cylinder is not under pressure to prevent injury during dismantling.