PULLEY-CRANKSHAFT 1949456 - Caterpillar

Pilot oil from the pilot control valves flows through pilot lines to the ports on the right side of the main control valve to perform the opposite operation.The following example is given for the BOOM RAISE operation and the BOOM LOWER operation. Machine operations for a stick operation, bucket operation, travel operation, and swing operation are accomplished in the same manner as the boom operation.When the joystick for the boom is moved to the BOOM RAISE position, pilot oil from pilot control valve (2) flows through pilot line (16) to boom I control valve (21) and boom II control valve (23). The pilot pressure shifts the boom I control valve and the boom II control valve. The oil delivery from the drive pump and the idler pump flows to the head end of the boom cylinders to perform the BOOM RAISE operation.When the joystick for the boom is moved to the BOOM LOWER position, pilot oil from pilot control valve (2) flows through pilot line (17) to boom I control valve (21). The pilot pressure shifts the boom I control valve. The BOOM LOWER operation is now performed.For more information concerning the operation of the boom, refer to Systems Operation, "Boom System".Pressure Sensors
Pressure sensor (8) is connected to pilot oil for boom down control. Pressure sensor (11) is connected to pilot oil for a swing RIGHT operation and swing LEFT operation. These two pressure sensors send an electrical signal to the machine ECM.When a boom DOWN function is performed, pressure sensor (8) sends an electrical signal to the machine ECM. The machine ECM then sends a signal to the following components:
PRV for boom regeneration valve (22) limits pilot oil to the boom regeneration valve.
The AEC system is activated to lower the engine rpm.
Swing brake solenoid valve (38) is activated to release the swing parking brake.When a swing operation is performed, pressure sensor (11) sends an electrical signal to the machine ECM. The machine ECM then sends a signal to the following components:
The solenoid valve for swing priority (19)
Swing brake solenoid valve (38) is activated to release the swing parking brake.Drive pump pressure sensor (41) and idler pump pressure sensor (42) are located on main control valve (3).
Pressure sensors (28) and (29) are connected to travel pilot control valve (27). Pressure sensor (9) is connected to pilot control valve (1) and pilot control valve (2). When all the joysticks and/or travel levers/pedals are in the NEUTRAL position, the pilot oil pressure to the pressure sensors is low. The AEC system is activated to lower the engine rpm.If any of the joysticks and/or travel levers/pedals are moved from the NEUTRAL position, the increased pilot oil pressure is sent to the pressure sensors. As pressure rises, the AEC system increases the engine rpm.If both travel levers/pedals and either one of the joysticks are moved from the NEUTRAL position simultaneously, pilot oil pressure will cause pressure at the sensors to rise. The increased pressure signals are detected in the machine ECM. The