16-2. PRINCIPLES OF OPERATION (CONT)
The fork tips lower port relief valve is connected to the head end of the cylinders. The relief valve is set at
725 psi (5064 kPa) to limit any external upward force on the forks.
g. Fork Sideshift System. The fork sideshift function, as with the previous two functions, is controlled by
the electric joystick and the attachment control valve. Hydraulic oil from the piston pump flows through the
control valve as in the other two systems. The third section of the attachment valve controls the left fork
(right cylinder) and the bottom (fourth) section controls the right fork (1eft cylinder).
Push the button on top of the electric joystick and move the joystick to the left and the third from the top right
solenoid is energized. The solenoid allows pilot oil to flow through the solenoid and push the spool in the third
section towards the left of the machine. System oil flows through the third section, pilots open a load
compensating check valve and allows oil to flow from the work port to the head end port of right cylinder
which moves the left fork to the left. Oil in the rod end of the cylinder flows back to the return circuit of the
attachment control valve.
If the button is held and the electric joystick is moved to the right, the third from the top left solenoid is
energized. The oil flow through the third section of the attachment control valve is similar to the above left
fork motion but the flow to the cylinder is reversed. Oil pressure is sent to the rod end port of the right
cylinder which retracts the cylinder and moves the left fort to the right.
The above description of hydraulic function for the left fork can also be applied to the right fork. The button is
held down while the electric joystick is moved front to rear to control the right fork position.
While holding button down on top of the electric joystick and moving the joystick diagonally from center will
energize two solenoids at the same time. These four diagonal.positions can move the forks apart, together,
both right, or both left depending on which combination of solenoids is used.