9. COMBINED BOOM UP AND BUCKET OPERATION ARM CYLINDER BUCKET CYLINDER BOOM CYLINDER TRAVEL MOTOR P5 P4 Pi2 Rs MU Pi1 Pn1 Pn2 SWING MOTOR PBa PAb1 P02 P04 PDb2 A2 PUMP A1 PUMP PILOT PUMP HYDRAULIC TANK 330S3HC25 When the boom up and bucket functions are operated, simultaneously each spool in the main control valve is moved to the functional position by the pilot oil pressure from the remote control valve. The oil from the A1 pump flows into the boom cylinders through the boom 2 spool in the left control valve. The oil from the A2 pump flows into the boom cylinders and bucket cylinder through the boom 1 spool, bucket spool and the parallel and confluence oil passage in the right control valve.
Also, when the boom up and bucket in functions are operated simultaneously, the boom up operation preference function is operated by the pilot pressure P04 and then the bucket spool transfers in the half stroke not full stroke (refer to page 2-43). Therefore, the most of pressurized oil flows into boom 1 spool than the bucket spool to make the boom up operation more preferential. The boom and bucket are operated.
3-32 BC1 N RV2 Cck DR9 Co P05 Do PCo PDo OPTION Ca Da BC2 NRV1 Cco CoR AkR LCk1 LCk2 DoR LCo CaR DaR BUCKET Bucket in stroke limiter spool BbkR DR7 CRa PaL ARM1 LCa LCa2 ARM2 PAa2 DR6 Csp Db2 BOOM2 Ccb SWING P/R LCar LCbk BbR ARM REGEN P02 Abk PBrc PAbk DR4 Cs Ds PCs PDs DR5 SWING LCs AbR LCb Relief valve CRb BOOM1 P03 DR3 Ctl Dtl PCtl PDtl SH Patt ( TR RIG AVH ET L) PS DR1 P01 PtrPS TS P03 DR3 Ctl Dtl PCtl PDtl Patt (RIGHT) TRAVEL DR1 BtR AtR (LEFT) TRAVEL MRV