Hydraulic lock structure and working principle

Hydraulic lock structure and working principle

Hydraulic lock refers to two liquid-controlled check valves composed of two-way hydraulic lock, 

the principle is that the two liquid-controlled check valves take the pressure of the other oil circuit as the pilot oil,

 when there is no pressure in one pipeline, the other side is closed at the same time

1. Hydraulic lock structure diagram and symbol

The structure diagram and only symbols of the hydraulic lock are as follows: The hydraulic lock is composed of two identical hydraulic control check valves,

 with a piston in the middle

2. Working principle of hydraulic lock

When the hydraulic oil enters from port A1, the pressure is greater than the opening pressure of the check valve, the check valve opens, 

A1 and A2 are connected, the oil flows from port A1 to port A2, at the same time, the pressure oil entering from port A1 will push the piston to the right, 

the piston will open the right check valve, and the oil can return from B2 to B1.

When the oil pressure is reduced, the piston returns to the median under the action of the spring, the two check valves will be closed, the flow is blocked, 

and the hydraulic lock can play the role of both on and off.

3. When to use hydraulic locks

Hydraulic lock is mainly used for static locking load, can only achieve switching action, such as: truck crane leg, 

load is relatively small and relatively stable changes in some airport elevator, horizontal directional drilling, shear difference elevator, fire trucks, 

sanitation trucks and other equipment. Not suitable for dynamic speed control with heavy load and large load change (start smoothly, drop to prevent stall)