260 Hydraulic System
Proportional Valve
EXPERT™ vehicles with an automated arm are equipped with a proportional valve (see Figure 5-5), as
part of the arm vane pump, that powers all arm functions (gripper [open/close], lifting arm [extend/
retract, up/down], chute [left/right], etc.) and other options.
As such, the amount of flow coming out of it will depend on the position of the spool inside a valve
section. This feature, called proportional control, allows infinite control of the arm speed and
movement.
Each section of this valve is actuated by an electric coil located under the valve.
Figure 5-5
Proportional valve
• Input/output cover: provided with main relief valve
• Chute section (optional): not proportional, with load sensor relief
• Gripper section (open/close): not proportional, with load sensor relief
• Lifting arm section (up/down): proportional, no load sensor relief
• Lifting arm section (extend/retract): proportional, no load sensor relief
Input /output cover
Chute
(co-mingle units only)
Gripper (open/close)
Lifting arm (up/down)
Lifting arm (extend/retract)
Electric coil