SYSTEM / Hydraulic System Travel and Arm Roll-In Operation 1. When the arm is rolled in while traveling, pilot pressure shifts the travel, arm 1 and 2 spools. 2. At the same time, right travel pilot pressure shifts the flow combiner valve control spool in the sig- nal control valve. Pressure oil from the flow com- biner valve control spool is routed to the flow combiner valve and shifts the flow combiner valve. 3. Pressure oil from pump 1 drives the right travel motor through the right travel spool. 4. At the same time, pressure oil from pump 1 passes through the flow combiner valve and the left travel spool and drives the left travel motor. 5.
Pressure oil from pump 2 flows into the arm cyl- inder through the arm 1 spool and moves the arm. 6. Consequently, pressure oil from pump 2 is used only to operate the arm. Pressure oil from pump 1 is equally routed to both the right and left travel motors and ensures that the machine can travel straight. T2-4-20