Hyster A238, Руководство пользователя

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Emergency Lowering Valve
The lift cylinders will NOT lower if lift cylinder
pressure is insufficient to overcome the combined
force of the spring and the oil pressure at the pilot
side of the check valve. This situation occurs for
instance, when the weight of the carriage has been
removed from the lift cylinders. The emergency
lowering valve provides the possibility to manually
relieve lift cylinder pressure to tank.
The emergency lowering valve combines three
functions in one assembly. The anti-cavitation valve
opens when lift cylinder pressure is lower than tank
pressure. The shock valve opens when (under
extreme conditions) lift cylinder pressure exceeds
35 MPa (5076 psi). Turning the hand wheel clock
wise, opens the shock valve against spring force.
Operation
The emergency lowering valve is located at the left
hand side of the main control valve, and can be
accessed after removal of the cover above it. See
Figure 6.
Initial turning of the hand wheel CLOCKWISE will
remove play between spindle and shock valve.
Continued turning clockwise opens the shock valve
against spring force and allows oil from the lift
cylinders to drain to tank. See Figure 7.
The emergency lowering valve closes by turning the
hand wheel COUNTER CLOCKWISE. After the
spindle loses contact with the shock valve, continue
to turn the hand wheel counter clockwise as far as it
goes. This allows the Anti-Cavitation Valve to open
when necessary.
Immediately after, turn the hand wheel one turn
back to prevent damage in case an operator is not
familiar with the correct direction of hand wheel
rotation.
1. EMERGENCY LOWERING CONTROL VALVE
Figure 6. Emergency Lowering Control Valve - Location
4000 SRM 1664 Description And Operation
5