Jacobsen AR-3 - Raise Circuit Schematic and Theory of Operation

6-18 4181384 First Edition
HYDRAULICS
6
Raise Circuit Schematic and Theory
of Operation
See Figure 6-12.
System Conditions:
• Engine running
• Weight transfer switch in the off position
• Raise/lower joystick in the raise position
NOTE
See “Raise/Lower Circuit—Theory of Operation” on
page 4-36 for the electrical operation of this circuit.
Operating pressure oil is supplied to the lift valve by the
steering circuit, and oil flows to the primary weight
transfer valve in the lift valve. With the primary weight
transfer valve de-energized, and the raise valve
energized, high-pressure oil flows through the primary
weight transfer valve and raise/lower valve. The oil then
unseats the check valve and flows to the check valve in
the secondary weight transfer valve. The check valve
blocks the oil and forces it to the rod end of the lift
cylinders, raising the cutting units.
Oil from the piston end of the lift cylinders flows through
the oil cooler and back to the hydraulic tank.