8. COMBINED BUCKET AND TRAVEL OPERATION 8. COMBINED BUCKET AND TRAVEL 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 480A3HC27 When the bucket and travel functions are operated, simultaneously the bucket spool and travel spools in the main control valve are moved to the functional position by the pilot oil pressure (pa8, pb8, pa1, pb1, pa6, pb6) from the remote control valve, and the straight travel spool is pushed to the right by the oil pressure from pilot pump.
The oil from the A1 pump flows into the travel motors through the RH travel spool of the left control valve and the LH travel spool of the right control valve via the straight travel spool of the control valve. The oil from the A2 pump flows into the bucket cylinder through the bucket spool via the confluence oil passage. The bucket is operated and the machine travels straight. 3-31 3-31 A5 pb5 ARM 1 pa5 B4 A4 pb4 pa4 A3 B3 pb3 B2 pa3 A2 OPTION 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