- Load Haul Dump:
- R1700G (S/N: 8XZ)
Reference: Service Magazine, SEPD0659, 09 December 2002, "A New Switch is Used for the Ride Control System".
Because the ride control switch has been changed the testing and charging procedure for the ride control accumulator contains incorrect information. The following information replaces the former information.
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| Illustration 1 | g00943289 |
Location of the ride control switch (14) Ride control switch (15) Ride control indicator | |
Ride control switch (14) is mounted in the switch panel in the operator's station. Ride control indicator (15) is located on the indicator panel in the operator station.
When the ride control system is activated, the head end of the lift cylinders are connected to ride control accumulator (2). The ride control accumulator provides a cushioning effect to the head end oil, allowing the lift cylinders to extend and retract slightly. The bucket can move as a balance weight against the movement of the machine.
Ride control switch (14) has three positions the OFF position, the AUTO position and the SERVICE position.
OFF Position
Ride control solenoid valve (6) is a normally closed valve. When the lift spool in main control valve (3) is in the HOLD position and ride control switch (14) is in the OFF position, the coil in ride control solenoid valve (6) is not energized. A spring in ride control solenoid valve (6) holds the solenoid valve spool in the closed position. With the solenoid valve spool in the closed position pilot oil is blocked.
When the ride control system is in the OFF position, the orifice between lift cylinders (1) and ride control accumulator (2) allows a continual sensing of the lift cylinder pressure. When a load is in the bucket, pressure increases in the head end of the lift cylinders. This pressure passes through the orifice into ride control accumulator (2) to compress the nitrogen charge. This prevents the bucket from moving when the ride control system is activated.
AUTO Position
When ride control switch (14) is moved to the AUTO position, the ride control system will automatically activate when the machine ground speed exceeds 5 km/h (3 mph). Ride control indicator (15) will illuminate when the ride control system is activated.
When the lift spool is in the HOLD position and ride control switch (14) is moved to the AUTO position and the ground speed of the machine exceeds 5 km/h (3 mph), the coil in ride control solenoid valve (6) is energized. When the solenoid valve coil is energized it causes the solenoid valve spool to move against the spring force to the OPEN position, allowing pilot oil to flow into ride control diverter valve (8) .
The pilot oil causes the ride control diverter valve spool to move against the spring force to the OPEN position. Head end oil is open to ride control accumulator (2). Lift cylinder rod end oil is open to hydraulic tank (11) .
As the machine moves across rough terrain with a loaded bucket, the forces of the load act against the lift cylinders and the oil in the head end of the lift cylinders. The oil in the head end of the lift cylinders is felt at ride control accumulator (2) .
SERVICE Position
The SERVICE position is used for testing and troubleshooting the ride control system.
When ride control switch (14) is moved to the SERVICE position, the ride control system will be activated. Ride control switch (14) will return to the OFF position when released. Ride control indicator (15) will illuminate when the ride control system is activated.
When ride control switch (14) is moved to the SERVICE position, the ride control system operates the same as "AUTO Position" except that the system is activated regardless of ground speed.