STRUCTURE AND FUNCTION SUSPENSION LOCK CYLINDER CIRCUIT Purpose The undercarriages of wheeled hydraulic excava- tors have one of the two driven axles oscillating mounted. This makes it possible to fully utilize the excavator's rimpull in rough terrain - all of the wheels being constantly in contact with the ground. An oscillation blocking ram is fitted on each side of the undercarriage to block the axle during digging or lifting work. Blocking the axle increases the excavator's stability. Function The oscillating axle (3) is mounted in bearing (2) in the middle of the excavator.
The two rams (1) which are full of hydraulic oil are connected through pipe- lines to the oscillation lock solenoid valve (4). When the excavator is being moved, the oscillation lock solenoid valve should be de-energized so that the hydraulic oil in the ram can be returned to tank as the axle is oscillating up and down. Before com- mencing excavating operations, the oscillation lock solenoid valve should be energized to pressurize the oil in the rams. This will lock the axle in the posi- tion it is in. 1. Ram 2. Axle oscillation point 3. Oscillating axle 4. Oscillation lock solenoid valve 5. Pilot pressure reducing valve 6. Hydraulic tank 7. Swivel joint 8. Check valve 10-20