HOSE 5N5566 - Caterpillar

When the pilot control valve for the hook is moved to the RAISE position, a signal is sent to a HOOK RAISE port (pilot pressure) (b1). This signal enters manifold (1) and the oil travels through a resolver network. The resolver network consists of shuttle valves (8) and (7). The shuttle valves are shifted and the signal is allowed to pass through each one.See Hydraulic Systems Operation, "Shuttle Valve" for more information.Then, the signal travels to three-way pilot control valve (4). The signal causes valve (4) to shift. This opens a passage of signal oil to two-way pilot control valve (3) .See Hydraulic Systems Operation, "Pilot Control Valve (Three-Way)" for more information.Pump pressure enters manifold (1) through port (P). A small portion of this oil becomes a signal which travels to three-way pilot control valve (4). Since this valve is shifted open, the signal is allowed to pass through the valve. Then, this signal travels to two-way pilot control valve (3). This signal shifts valve (3) to the OPEN position. Now, pump pressure is allowed to pass through valve (3) .See Hydraulic Systems Operation, "Pilot Control Valve (Two-Way)" for more information.Part of the pump pressure that enters manifold (1) travels to pressure reducing valve (5). The pressure is reduced to approximately 5170 kPa (750 psi). This reduced pressure travels through check valve (6). First, this pressure travels to accumulator port (AC). The pressure also charges the accumulator to 5170 kPa (750 psi). Next, the reduced pressure travels to pilot pressure port (PP). This pressure supplies the pilot control valves for the hook and the boom. The return flow from the pilot control valves enters port (PD). This oil flows to drain port (DR) and the oil flows to the tank.See Hydraulic Systems Operation, "Pressure Reducing Valve" for more information.See Hydraulic Systems Operation, "Check Valve" for more information.The signal from HOOK RAISE port (b1) also travels to hook control valve (10) through an exterior line. This signal shifts the spool in valve (10) to the HOOK RAISE position. Pump pressure travels from two-way pilot control valve (3) to hook control valve (10) through internal passages (PG) and (CG). The passage through Internal passage (CG) is blocked in this spool position. The pump pressure travels through passage (PG) and a check valve in valve (10). This pressure travels through the valve spool to HOOK RAISE port (B1). From port (B1), the oil pressure travels to the winch motor and the hook winch raises the hook.See Hydraulic Systems Operation, "Pipelayer Winches" for more information.The oil from the winch motor returns through port (A1). This oil travels through the valve spool in valve (10) again. Then, the oil travels to the spool in boom control valve (11). The boom spool is in the HOLD position. The oil is allowed to pass through the boom spool to the tank.Boom in RAISE Position and Hook in HOLD Position
Illustration 5 g00465454
Schematic of the boom and hook control valve in the BOOM RAISE position (1) Manifold (2)