SERV1851 02/08
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Text Reference Boom, Stick, and Bucket Circuits
STICK REGENERATION HYDRAULIC CIRCUIT Stick Cylinder
To Tank
STICK IN - SLOW WITHOUT REGENERATION
To Stick Out
To Stick In
Stick 1 To Stick 2 Valve From Idler Pump
Line Relief Valves
To Stick 2 Valve
Stick Drift Reduction Valve
Stick Unloading Valve
Swing Priority Valve
From Idler Pump
From Idler Pump From Stick 2 Valve Check Valve
Stick Regeneration Valve
131
Slow STICK IN - No Regeneration Depending on the position of the stick, for a slow STICK IN, regeneration may not be required due to the supply oil from the pump being able to fill and pressurize the head end of the stick cylinder to force the stick in. For a slow STICK IN the pilot signal is reduced and will only partially shift the stick 1 spool. The stick 2 control valve may or may not shift. Pilot oil shifts the regeneration valve down, which allows return oil to be sensed at the check valve. The regeneration valve also allows pump supply oil pressure to be sensed at the unloading valve. The unloading valve does not shift due to the supply oil pressure being below the setting of the unloading valve spring. A reduced NFC signal is sensed at the idler pump, and the pump upstrokes to provide flow.
