5) WHEN THE RCV LEVER IS IN THE ROLL BACK (retract) POSITION Steering unit P port 3 Steering unit LS port SX P Pst T b1 b3 b2 4 B.D/F B.U CRAWD DUMP 1 3 4 2 P T 1.1 2.1 A1 7 P1 T Cut off valve P1 port Return line 24 X1 PS Return line 1 18 B1 E/G 17 L L1 S1 74096WE07 В If the RCV lever (4) is pulled left, the bucket spool is moved to roll back position by pilot oil pressure from port 4 of RCV. The oil from main pump (1) flows into main control valve (3) and then goes to the large chamber of bucket cylinder by pushing the load check valve of the bucket spool. The oil at the chamber of bucket cylinder (9) returns to hydraulic tank (17). When this happens, the bucket roll back.
When the rolling speed of bucket is faster, the return oil from the small chamber of bucket cylinder combines with the oil from the pump, and flows into the large chamber of the cylinder. This prevents cylinder cavitation by the negative pressure when the pump flow cannot match the bucket rolling speed. В В В В 6-9 8 LH 2 A2 ( ) ( ) Dump )( Floating Down ) ( Rollback Up Up