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4.4.4 Governor valve
The governor valve controls the lowering speed of pallet fork and plays the safety role in case of accidents etc.,
like the rubber hose broken under high pressure. Refer to the figure (Fig.4-15)
Fig.4-14 Lifting cylinder
The governor valve (I.e. throttle valve) is installed in the lifting oil line to restrict the falling speed when the
pallet fork is under heavy load. The structure is shown in Fig.4-16. When the slide valve of multi-way valve is
placed at the position "Lifting", the high pressure oil from the multi-way valve passes through A, B, the holes C,
D, E, F and the cavity G, and flows into the lifting cylinder without subject of throttle. When the multi-way
valve is at the position "Lowering", the oil from the lifting cylinder will flow the whole valve through the cavity
G, the holes F, E, D, C and B, A. Now the pressure difference will produce between the cavities A and B and
draw up the ball valve. When the difference of pressure is more than the elastic force of spring, the valve
element will move to the right resulting in the reduction of oil mass with the decrease of the holes D and C, as
well as the flow through the throttle hole.
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