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| Illustration 1 | g00550914 |
(1) Control manifold (2) Solenoid valve (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
The control manifold (1) maintains the selected angle of the work tool as the lift arms are raised. The control manifold only functions during the RAISE function. During the LOWER function, the control manifold does not affect the operation of the machine.
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| Illustration 2 | g00551233 |
(2) Solenoid valve (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
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| Illustration 3 | g00666165 |
(3) Automatic leveling switch | |
The solenoid valve (2) enables the control manifold. The solenoid valve is controlled by the switch (3). The switch (3) is located in the second position from the left side of the instrument panel. The instrument panel is located to the left and above the ignition switch.
When you start the engine, solenoid (2) is energized. The control manifold is not activated. Oil flows through port (A) to solenoid (2). The oil flows through the top section of solenoid (2) and through port (B). Then, the oil flows to the lift spool.
Press the bottom of the switch in order to activate the self-leveling function of the control manifold. When you press the bottom of the switch, solenoid (2) is de-energized. Oil flows through port (A) to the divider spool and to the unloading spool. Press the top of the switch in order to deactivate the self-leveling function of control manifold. Solenoid (2) is energized.
Self-Leveling Operation (Raising the Work Tool)
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| Illustration 4 | g00551505 |
(4) Flow divider valve (5) Unloading spool (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
The control manifold is activated. Solenoid (2) is de-energized. When the tilt control valve is in the HOLD position and the lift control valve is in the RAISE position, oil from the lift control valve enters the head end of the lift cylinders. As the lift cylinders extend, oil from the rod end of the lift cylinder enters port (A) .
The oil enters the flow divider valve (4). The hydraulic oil divides into two loops. One loop flows through the fixed orifice. The second loop flows through the adjustable orifice. The flow divider valve (4) balances the pressure between the head end of the tilt cylinder and the rod end of the lift cylinder. When the pressure between the head end of the tilt cylinder and rod end of the lift cylinder are kept in balance, the load will stay level.
The oil that flows through the fixed orifice flows out of port (B) and back to the tank. The variable orifice adjusts to the flow of oil from the rod end of the lift cylinders. The oil flows through the divider spool. Then, the oil flows to the unloading spool. The ports for the unloading spool are blocked. The oil will flow through the check valve and out port (D). From port (D), oil flows to the head end of the tilt cylinders and to the tilt control valve.
The internal ports are blocked in the tilt control valve. Because the internal ports are blocked in the tilt control valve, the oil flows to the head end of the tilt cylinder. As the tilt cylinders extend, the oil from the rod end of the tilt cylinders flows into port (C) .
The resistance to movement in the tilt cylinders causes pressure in the oil line from port (D). The check valve blocks oil. The resistance to movement in the tilt cylinders causes pressure. The pressure is great enough to open the unloading spool (5). The oil flows through the unloading spool and out port (B) back to the tank.
Hydraulic oil flows through the unloading spool. The oil flow reduces the pressure through port (C). The centering spring in the unloader valve (5) shifts the unloading spool.
When the fixed orifice loop pressure increases, the pilot oil shifts the flow divider (4). The oil will flow through the flow divider and out port (B) .
Lowering the Work Tool
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| Illustration 5 | g00551970 |
(5) Unloading spool (6) Check valve (7) Check valve (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
When the tilt control valve is in the HOLD position and the lift control valve is in the LOWER position oil enters the control manifold through port (B). The oil opens check valve (6). The oil flows through port (A) to the rod end of the lift cylinders.
Oil flows from the head end of the lift cylinders and branches. Part of the oil flows to the ball valve. The oil flow is blocked. The oil flows to the lift control valve. Then, the oil flows through the valve to the tank.
Tilting the Work Tool Forward
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| Illustration 6 | g00551970 |
(5) Unloading spool (6) Check valve (7) Check valve (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
When the lift control valve is in the HOLD position and the tilt control valve is in the TILT FORWARD position, oil flows from the pump toward the head end of the tilt cylinders and branches. The oil flows into the control manifold through port (D), but the flow is blocked by the check valve (7). Then, the oil flows to the head end of the tilt cylinders.
Hydraulic oil from the rod end of the cylinders flows toward the tilt control valve and branches. Oil enters the control manifold through port (C), but the flow is blocked by the unloading spool (5). The control manifold is used during lifting operations only. Then, the oil flows to the tilt control valve and to the tank.
Tilting the Work Tool Backward
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| Illustration 7 | g00551970 |
(5) Unloading spool (6) Check valve (7) Check valve (A) Oil from the rod end of the lift cylinders (B) Oil for the lift control valve (C) Oil for the rod end of the tilt cylinders (D) Oil for the head end of the tilt cylinders | |
When the lift control valve is in the HOLD position and the tilt control valve is in the TILT BACK position oil flows into the rod end of the tilt cylinder from the tilt control valve. Oil also flows into the control manifold through port (C), but the flow is blocked by the unloading spool (5). Oil flows from the head end of the tilt cylinder to the tilt control valve and back to the tank. Oil from the head end of the tilt cylinder also flows to the control manifold through port (D), but the flow is blocked by the check valve (7) .