Independent operation of the stabilizers allows the machine to be leveled when the machine is operating on uneven ground.
Stabilizers are installed as optional equipment on TH355, TH360, TH460 and TH560 machines only. Stabilizers are not available on TH350 machines.
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| Illustration 1 | g00945248 |
Control Valve Gp (Stabilizer) (1) Bank valve 2 (stabilizer) (2) Control valve (right stabilizer) (3) Control valve (left stabilizer) (4) Inlet manifold (5) Electronic pilot valve (stabilizer) (6) Valve ECM (7) Outlet manifold | |
The control valve Gp (stabilizer) is located in the center of the stabilizer frame at the front of the machine.
The control valve Gp (stabilizer) includes the following components:
- Electronic pilot valve (stabilizer) (5)
- Bank valve 2 (stabilizer) (1)
The electronic pilot valve (stabilizer) includes the following component:
- Valve ECM (6)
The bank valve 2 (stabilizer) includes the following components:
- Inlet manifold (4)
- Control valve (right stabilizer) (2)
- Control valve (left stabilizer) (3)
- Outlet manifold (7)
Reference: See Systems Operation Section, "General Information" for more information.
The stabilizer system includes the following components:
- Switch (LH stabilizer)
- Switch (RH stabilizer)
- Pressure switches (stabilizer cylinders)
- Switch (fully retracted boom)
- Control valve Gp (stabilizer)
- Lock valve
- Cylinders
The lock valve includes the following components:
- Dual overcenter valves
- Check valves
The stabilizers are installed on each side of the stabilizer frame at the front of the machine. A lock valve is attached by hydraulic pipes to each stabilizer cylinder.
The stabilizers are operated by stabilizer cylinders. The stabilizer cylinders are controlled by a control valve Gp (stabilizer) and a lock valve. The lock valve is mounted on the stabilizer cylinder.
The top section of the control valve Gp (stabilizer) operates the stabilizer cylinder (left side), and the bottom section operates the stabilizer cylinder (right side).
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| Illustration 2 | g00945862 |
(8) Left stabilizer switch (9) Right stabilizer switch | |
Both of the sections for the stabilizer control valve are operated by solenoids that are controlled by switches (8) and (9). The switches are mounted on the dash panel. The switches are three-position rocker switches, which are spring centered.
The stabilizer cylinders are equipped with lock valves. The lock valves lock oil into both sides of the cylinders when switches (8) and (9) are in the HOLD position. The lock valves provide the following functionality:
- Maintain the desired position of the stabilizer legs within the limits of drift that are defined by the specification of the valve.
- Prevent overrun of the stabilizer legs while the legs are being lowered.
- Prevent the stabilizer legs from collapsing in the event of a burst hose.
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| Illustration 3 | g00945848 |
(10) Pressure switch | |
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| Illustration 4 | g00886074 |
(11) Indicator for the stabilizer | |
Pressure switches (10) are installed in the stabilizer cylinders. When the cylinders are extended and the stabilizers are supporting a predefined weight, the contacts in the pressure switches will close and indicator (11) on the dash panel will illuminate. When the machine is equipped with a rear axle lock, a signal is sent to the machine ECM when the stabilizers are in this position, and the machine ECM then allows full movement of the boom.
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| Illustration 5 | g00945847 |
(12) Switch (fully retracted boom) | |
Switch (12) for the boom retract is installed on the front left side of the fixed boom section. The switch sends a signal to the machine ECM in order to inhibit the function for raising the stabilizer when the boom is extended. This function is available only if the machine ECM is equipped with a feature to inhibit lateral stability.
The following text describes the procedure to operate the right stabilizer. The procedure for operating the left stabilizer is the same procedure as operating the right stabilizer.
Stabilizer cylinders (hold)
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| Illustration 6 | g01022538 |
Hydraulic Schematic for the Stabilizers (Hold) (10) Pressure switch (stabilizer) (13) Lock valve (14) Right stabilizer cylinder (15) Check valve (16) Load Control valve (17) Spool (20) Proportional pilot reducing valve (22) Pilot supply oil (23) Return oil to tank (24) Pump supply oil (25) Load signal (26) Return oil to tank (27) Proportional pilot reducing valve | |
When the dash panel switch is released, the solenoid in proportional reducing valve (20) is de-energized. This causes the spool in valve (20) to move to the left. The supply of pilot oil is now blocked.
Spool (17) is spring centered to the HOLD position. When spool (17) is returned to the HOLD position, supply oil from the pump is blocked by the closed center of the spool. Check valve (15) in load control valve (16) is seated by the valve spring. This blocks oil in the head end of stabilizer cylinder (14). Oil is also blocked in the rod end of the stabilizer cylinder by the valve stem in lock valve (13). A spring in the lock valve overcomes the pressure of the blocked oil from the rod end of the cylinder in order to close the valve.
The pressure sensor for the stabilizer (10) signals the ECM when the stabilizers are under load.
Stabilizer cylinders (raise)
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| Illustration 7 | g01022552 |
Hydraulic Schematic for the Stabilizers (Raise) (1) Bank valve 2 (stabilizer) (2) Control valve (right stabilizer) (10) Pressure switch (stabilizer) (13) Lock valve (14) Right stabilizer cylinder (15) Check valve (16) Load Control valve (17) Spool (18) Line (19) Pressure compensating valve (21) Check valve (22) Pilot supply oil (23) Return oil to tank (24) Pump supply oil (25) Load signal (26) Return oil to tank (27) Proportional pilot reducing valve (28) Check valve (29) Lock valve (30) Proportional pilot reducing valve | |
To raise the right stabilizer cylinder, press the stabilizer switch on the dash panel to the left. The switch energizes proportional reducing valve (30) and the spool is moved to the right. Pilot oil from the main control valve (implement) then flows past the open spool in order to move spool (17) to the position for raising the stabilizer.
The machine ECM will ramp up the command to the stabilizer valve ECM when switch (9) is pressed. The ramp up time is approximately two seconds. The scale of the ramp up is adjustable in ET.
Pump supply oil then flows past open spool (17) and the pump supply oil opens pressure compensating valve (19). Oil flows through the pressure compensating valve. The oil unseats check valve (21), and flows past open spool (17) to load control valve (16) .
When the spool in pressure compensating valve (19) has been fully opened, pressurized oil will enter the load signal system. Load signal pressure is connected to the pressure and flow compensator valve on the main pump through line (18). This ensures that the highest system pressure controls the pump output. The pump upstrokes in order to meet the flow demand of the stabilizer.
Oil from the stabilizer control valve flows into load control valve (16). The oil flow causes check valve (28) to open. The oil passes through the check valve and into the rod end of right stabilizer (14). As the oil in the rod end of the stabilizer cylinder increases, the piston begins to move and the stabilizer cylinder is retracted.
Simultaneously, pressurized oil acts against the spring in lock valve (29) to open the lock valve. As stabilizer cylinder (14) retracts, the oil flows from the head end of the cylinder to the open lock valve (29). Oil flows from the lock valve back to the hydraulic tank through bank valve (1) and the main control valve (implement).
Stabilizer cylinders (lower)
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| Illustration 8 | g01022582 |
Hydraulic Schematic for the Stabilizers (Lower) (1) Bank valve 2 (stabilizer) (2) Control valve (right stabilizer) (10) Pressure switch (stabilizer) (13) Lock valve (14) Right stabilizer cylinder (15) Check valve (16) Load Control valve (17) Spool (18) Line (19) Pressure compensating valve (20) Proportional pilot reducing valve (21) Check valve (22) Pilot supply oil (23) Return oil to tank (24) Pump supply oil (25) Load signal (26) Return oil to tank (27) Proportional pilot reducing valve | |
To lower the right stabilizer cylinder, press stabilizer switch (9) to the right. The switch energizes the solenoid in proportional reducing valve (20) and the spool is moved to the right. Pilot oil from the main control valve (implement) then flows past the open spool in order to move spool (17) in right stabilizer valve (2) to the position for lowering the stabilizer.
The machine ECM will ramp up the command to the stabilizer valve ECM when switch (9) is pressed. The ramp up time is approximately two seconds. The scale of the ramp up is adjustable in ET.
Pump supply oil then flows past the open spool (17) and the pump supply oil opens pressure compensating valve (19). Oil flows through the pressure compensating valve. The oil unseats check valve (21), and flows past open spool (17) to load control valve (16) .
When the spool in pressure compensating valve (19) has been fully opened, pressurized oil will enter the load signal system. Load signal pressure is connected to the pressure and flow compensator valve on the main pump through line (18). This ensures that the highest system pressure controls the pump output. The pump upstrokes in order to meet the flow demand of the stabilizer.
Oil from the control valve Gp (stabilizer) flows into load control valve (16). The oil flow causes check valve (15) to open. The oil passes through the check valve and into the head end of right stabilizer cylinder (14). As the pressure and volume of oil in the head end of the stabilizer cylinder increases, the piston begins to move and the stabilizer cylinder is extended.
Simultaneously, pressurized oil acts against the spring in lock valve (13) to open the lock valve. As the stabilizer cylinder extends, the oil flows from the rod end of stabilizer cylinder (14) to the open lock valve (13). Oil flows from the lock valve back to the hydraulic tank through bank valve (1) and main control valve (implement).