CAB GP-ENCLOSED ROPS 1942707 - Caterpillar

Illustration 1 g01093750
Apron circuit in RAISE position
(1) Sequence and pressure control valve
(2) Snubber
(3) Pressure switch
(4) Actuator for the bowl
(5) Actuator for the apron
(6) Actuator for the ejector
(7) Valve spool for the apron
(8) Valve spool for the ejector
(9) Valve spool for the bowl
(10) Actuator for the ejector
(11) Actuator for the apron
(12) Actuator for the bowl
(13) Main control valve
(14) Apron cylinder
(15) Main relief valve
(16) Pilot oil supply line
(17) Vent line from carry-check valve
(18) Vent line from quick-drop
(19) Shuttle valve
(20) Screen
(21) Pilot oil filter
(22) Solenoid and pressure reducing valve
(23) Oil line from the main control valve to the carry-check and quick-drop valve
(24) Carry-check and quick-drop valves
(24A) Quick-drop valve (two)
(24B) Check valve (two)
(24C) Carry-check valve (two)
(24D) Oil line from the carry-check and quick-drop valve to the rod end of the cylinder
(25) Line from main control valve to the tank
(26) Line from cushion-hitch pump
(27) Line to cushion-hitch valve
(28) Bowl cylinder (two)
(29) Line for equalization of bowl cylinders
(30) Line to steering system
(31) Ball valve
(32) Oil filter
(33) Hydraulic tank
(34) Gear pump (hydraulic and steering)
(35) Cushion-hitch pump
(36) Case drain screen for the cushion-hitch pump
(37) Ejector cylinder
(38) Line from the main control valve to the tank
(39) Line from pump to sequence valve
(AA) Pressure oil from pump
(BB) Return oil
(CC) Blocked oil
(DD) Pilot oil Implement Pilot Circuit
Illustration 2 g00760418
Joystick control
When the engine is started with the joystick control in the HOLD position, the cushion-hitch pump (35) sends oil through line (26). Some of this oil flows through line (27) to the cushion-hitch valve. The rest of the oil flows through shuttle valve (19) and through screen (20) to solenoid and pressure reducing valve (22). Oil flows through solenoid and pressure reducing valve (22) to filter (21). This oil flows through line (16) to main control valve (13). Regardless of the joystick movement, the oil supply to the actuators is pilot supply oil. The pilot supply oil to the actuators is for the following implements: the bowl, the apron and the ejector.Lowering the Apron
When the thumb wheel on the joystick control is moved to the LOWER position, an electrical current is sent to the solenoid in actuator (11). The solenoid allows pilot oil to shift spool (7). The pump oil flows through the following items: valve spool (7), sequence valve (1) and rod end of apron cylinder (14). The hydraulic oil in the rod end moves the piston downward. When the piston moves down, the piston pushes the oil in the head end of the cylinder to sequence and pressure control valve (1). This oil passes through main control valve (13). Then, the return oil flows through line (38) into filter (32) and hydraulic oil tank (33).When the apron is lowered completely, pressure increases in the rod end of apron cylinder (14). When the oil pressure reaches 15000 kPa (2176 psi), the sequence valve (1) will open. Then, the pump oil flows through the following items: sequence valve (1), main control valve (13), oil filter (32) and hydraulic tank (33).When the thumb wheel is released valve spool (7) returns to HOLD position.