Theory of Operation
oil acts on shuttle valve (B), allowing pressure oil from
Boom cylinder controlled load lowering valves are used
the head end of the boom cylinder to flow through pilot
in the boom circuit. The function of the boom cylinder
valve (A). The oil then flows through the boom valve
controlled load lowering valve is to prevent the boom
and back to sump. The pilot oil acting on shuttle valve
from falling by maintaining pressure in the circuit in
(B) also vents through the shuttle, through the pilot
case of a hose or line rupture.
valve (A) and back to sump.
In the down position pilot oil acts on pilot valve (A)
moving it against spring force. At the same time pilot