8
The main working part of the forklift is the forks. The forks recognize the
loading, unloading, stacking and short-distance transportation for pallets or
cargo.
The forks are mounted on the carriage, by chain drive or inner mast moving
up and down, the carriage and forks lifts the goods off the ground or to be
stacked on racks. The chain transmission and inner mast overall movement are
achieved by the extension of the lift cylinder. Forklift operation process is
achieved by extending of the control cylinders (including tilt action).
Cylinder movement is controlled by a physical valve stem, and the oil
pressure is provided by the hydraulic pump.
The controlled safety valves in the lifting cylinders and tilt cylinder will
slow down the speed of mast lifting, lowering or tilting to ensures safety.
2.3 Electrical principle
2.3.1 Electrical system
The forklift electrical system includes driving and operation control, and lighting.
The forklift implements Curtis Instrument Controllers and i.e. CURTIS1232 AC
control assembly.
The controller has the indicator for power display, slowing down of mast lifting,
parking and hour meter display function. When the battery power is may be low,
the power meter will cut off the control circuit of pump motor to protect its
battery life. The forklift will not lift however can still drive, which means the
forklift should be charged immediately.
The hydraulic pump motor is a DC motor therefore not recommended for long
continuous operations. The lifting movements should have intervals, should not
be continuous, otherwise it can cause the motor to overheat
Special Note: If the forklift is used for a continuous period, the pump motor may
lack performance. The lack of performance is that the starter may not lift
properly. The latter one is represented as no lifting with the multi-way valve
control lever, pump motor will keep turning. If this occurs the forklift should be
turned off. Disconnect the battery and allow time to dissipate the overload.
