PLUG 0941882 - Caterpillar

Illustration 1 g00828984
Control Valve (Felling Head) (P) Pump port. (LS) Load signal port.The control valve (felling head) is located under the step in the engine compartment. The control valve (felling head) is composed of three control valves. These control valves control the following components:
Grapple arm cylinders
Collector arm cylinders
Lateral tilt cylinder
Illustration 2 g00828989
Schematic of Control Valve (Felling Head) (1) Control valve (feller buncher head). (2) Relief valve (load signal). (3) Valve section (tilt cylinder). (4) Valve section (collector arm cylinders). (5) Valve section (grapple arm cylinders). (A) Work port. (B) Work port. (LS) Load signal port. (P) Pump port. (T) Tank port. (X) Pilot port. (Y) Pilot port. The implement pump oil flows into the control valve (1) through pump port (P). The flow of implement pump oil is controlled by control valve (1). The oil flow is supplied to cylinders that are selected for operation.Return oil from cylinders enters control valve (1). Then, the oil flows from tank port (T) back to the hydraulic tank through the return line.The main spools of valve sections (3), (4), and (5) are shifted with pilot oil pressure. Pilot oil pressure is controlled by the solenoid valves of the pilot control valve (felling head).When one of the valve sections is activated, the main spool in the valve section begins to move. This movement creates a load signal pressure.The load signal oil flows from the load signal port (LS) to relief valve (2) and the implement pump. The load signal pressure controls the implement pump. An increase in the load signal pressure causes the implement pump to upstroke. A decrease in the load signal pressure causes the implement pump to destroke.When the load signal reaches a pressure of 22000 kPa (3200 psi), relief valve (2) opens allowing the oil to flow back to the tank. The load signal pressure will decrease causing the implement pump to destroke.The check valve in the load signal circuit prevents a load signal from a separate circuit to flow to the control valve.Reference: The valve sections of control valve (1) function in the same way as the valve section of the main control valve (boom). For a detailed explanation of the main spools and the line relief valves of control valve (1), refer to System Operation, "Control Valve (Boom, Stick, and Saw Tilt)".