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| Illustration 1 | g01279864 |
Partial hydraulic schematic (1) Blade cylinder (2) Swivel (3) Blade control valve (4) Main control valve (5) Main pump | |
The blade control lever is located next to the right joystick. The blade control lever has three positions:
- Blade raise
- Blade lower
- Blade float
Operation
When the operator performs a blade raise function, the blade control valve is shifted downward. Oil from main pump (5) flows through blade control valve (3), to swivel (2) and into the rod end of blade cylinder (1). Return oil flows out of the head end through swivel (2) into blade control valve (3) and back to the hydraulic tank. This causes the cylinder rod to extend. The extending of the cylinder rod causes the blade to rise.
When the operator performs a blade lower function, oil flows in the reverse direction of the blade raise function.
When the operator performs a blade float function, the blade control valve shifts two positions upward. See the Operation and Maintenance Manual, SEBU7452, "Blade Control" section in order to place the blade in the FLOAT position. Oil is allowed to flow from both the head end of the blade and the rod end of the blade. This allows the blade to float with the contour of the ground. If the ground level rises, oil from the head end of the blade cylinder is sucked into the rod end of the blade cylinder. If the ground level lowers, oil from the rod end of the blade cylinder is sucked into the head end of the blade cylinder. This causes the cylinder rod to float. The continuous flowing of oil between both the rod end of the cylinder and the head end of the cylinder causes the blade to float.