2. COMBINED SWING AND BOOM 2. COMBINED SWING AND BOOM UP UP OPERATION OPERATION ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER SWING MOTOR ps1 ps2 T3 T1 T2 T4 TRAVEL MOTOR A1 A2 FRONT PUMP REAR PUMP PILOT PUMP HYDRAULIC TANK 480A3HC21 When the swing and boom up functions are operated, simultaneously the swing spool and boom spools in the main control valve are moved to the functional position by the pilot oil pressure (pa2, pb2, pb3, pb7) from the remote control valve. The oil from the A1 pump flows into the swing motor through swing spool and the boom cylinder through boom 2 spool. The oil from the A2 pump flows into the boom cylinders through the boom 1 spool in the right control valve.
The upper structure swings and the boom is operated. Refer to page 3-9 for the boom priority system. 3-25 3-25 A5 pb5 ARM 1 pa5 B4 A4 pb4 pa4 A3 B3 pb3 B2 pa3 A2 OPTION Anti-drift valv BOOM 2 pb2 SWING DR3 pa2 B1 pc6 TRAVEL(LH A1 pb1 pa1 TRAVEL(RH) TRAVEL STRAIGHT pr1 P1 PSPT PP PA PH PS SWING TRAVEL( RH) TRAVEL(LH TRAVEL STRAIGHT A6 pb6 pa6 ) P3 P2