Reliable sealing of hydraulic cylinder is an important factor for its normal operation. If the original rexler A4VG180 series leaks seriously, it will not only reduce the working efficiency of the hydraulic cylinder, but even make it unable to work normally (such as failing to meet the requirements of load capacity and movement speed, etc.). Good dust prevention measures are conducive to improving the working life of the hydraulic cylinder.When the manual reversing valve is placed in the right position, the pressure oil output by the hydraulic pump enters into the rodless cavity of the four vertical hydraulic cylinders and the supporting legs extend through the rotary valve and the original rexroth A4VG125 series hydraulic lock (dual-liquid control one-way valve). When the manual reversing valve is placed in the left position, the pressure oil enters the rod cavity of the four vertical hydraulic cylinders respectively through the tubing and the hydraulic lock, and the supporting leg is retracted. Rotary valve can make the four legs of the hydraulic cylinder at the same time extended support or separate leveling, but also at the same time or separate folding.

In order to prevent hydraulic leg in the process of support "soft leg" phenomenon oil research plunger pump accessories (leg hydraulic cylinder under a large load, piston rod self-shrinking phenomenon), cause accidents, in each leg hydraulic cylinder oil road are installed two-way hydraulic lock. The working pressure of the overflow valve control circuit is set at 16MPa.