Shop Manual

20-113
Hydraulic-control Check Valve
(For power incline, rear ripper (optional), front scraper blade (optional))
1. Check Valve
2. Piston
3. Shell Body
4. Check Valve
5. Overflow Valve
The hydraulic-control check valve with safety
valve is mainly prevent the pressure variation
of hydraulic cylinder and protect hydraulic
cylinder from occurring abnormal pressure
due to the foreign force.
Operation
When operate the operation rod to extend the
oil cylinder, the oil enters into A
1
chamber
from oil pump and pushes the piston (2) and
the check valve (4), then the oil flows to the
bottom of hydraulic cylinder through B
1
chamber. The oil on the head of oil cylinder
back to oil tank from B
2
chamber and A
2
chamber.
When operate the operation rod to retract the
oil cylinder, the oil enters into A
2
chamber
from oil pump. When the pressure of A
2
chamber is increased, the check valve (1) is
pushed and opens the check valve (1). The oil
flows to the head of hydraulic cylinder from
B
2
chamber.
When the pressure of B
2
chamber is increased
to abnormal value of 250 kg/cm
2
or more due
to the impact, the overflow valve will be
opened and oil flows from B
2
chamber to B
1
chamber, which reduce the impact.