Bucket Circuit

137

For STICK IN, the shuttle valve is moved down by pilot oil from the joystick.

The shuttle valve allows oil in the lock valve spring chamber to flow to the tank.

Return oil from the stick cylinder rod end moves the lock check valve to the left against the lock check valve spring.

The open lock check valve allows oil flow from the rod end of the stick to return to the stick 1 control valve and the regeneration valve.

138

Bucket Circuit

The bucket circuit control valve operates as previously discussed. Two line relief valve and makeup valves are used to protect the lines from high pressures.

The bucket is only supplied by the drivepump. Pilot oil from the joystick is directed to the bucket control valve to shift the control spool.

When the control spool shifts, the NFCsignal to the drive pump is reduced and the pump upstrokes to provide flow.

For BUCKETCLOSE, the return oil from the rod end of the cylinder is restricted by the control spool to control the bucket speed.