UNDERCARRIAGE AR 2185861 - Caterpillar

Pilot Logic Network
The passage (79) is part of the pilot logic network. The pilot logic network is used to activate the straight travel valve. Refer to "Valve for Straight Travel" for more information on the pilot logic network .Boom Valve
The boom valve is controlled by the right hand joystick control. Move the joystick control forward in order to lower the boom. Move the joystick control backward in order to raise the boom. Refer to the Operation and Maintenance Manual, SEBU7203, "Joystick Controls" for more information on the joystick controls.HOLD Position for the Boom
Illustration 34 g00592827
(80) Inlet passages. (81) Openings in the spool. (82) Outlet passage. (83) Spool.When the joystick control is in the HOLD position, the oil enters the valve through the inlet passage (80). Then, the oil flows through the openings (81) in the spool (83) and into the outlet passage (82). Then, the oil flows to the bucket valve.RAISE Position for the Boom
Illustration 35 g00592828
(83) Spool. (84) Parallel passage. (85) Return passage. (A) Port. (B) Port.When the joystick control is in the RAISE position, the spool (83) shifts to the left. Oil is blocked from entering the inlet passages (80). Since the oil cannot enter the valve through the inlet passages, the oil enters the valve through the parallel passage (84). From the parallel passage, the oil flows to port (B) through the check valve. From port (B), the oil flows to the head end of the boom cylinder in order to extend the cylinder. Oil that is returning from the rod end of the cylinder enters the valve through port (A). From port (A), the oil flows to the return passage (85) .LOWER Position for the Boom
Illustration 36 g00592829
(83) Spool. (84) Parallel passage. (85) Return passage. (A) Port. (B) Port. (86) Passage.When the joystick control is in the LOWER position, the spool (83) shifts to the right. Oil is blocked from entering the valve through the inlet passages (80). Since the oil cannot enter the valve through the inlet passages, the oil enters the valve through the parallel passage (84). From the parallel passage, the oil flows to port (A) through the check valve. From port (A), the oil flows to the rod end of the boom cylinder in order to retract the cylinder. Oil that is returning from the head end of the cylinder enters the valve through port (B). From port (B), the oil flows to the return passage (85) .Pilot Logic Network
The passage (86) is part of the pilot logic network. The pilot logic network is used to activate the straight travel valve. Refer to "Valve for Straight Travel" for more information on the pilot logic network .Bucket Valve
The bucket valve is controlled by the right hand joystick control. Move the joystick control to the right in order to dump the bucket. Move the joystick control to the left in order to close the bucket. Refer to the Operation and Maintenance Manual, SEBU7203, "Joystick Controls" for more information on the joystick controls.HOLD Position for the