5-10t Internal Combustion Counterbalance Forklift Truck Operation & Maintenance Manual
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5.2.2 Brake Valve (Refer to Fig 5-3.)
(1) Non-Braking Status
Under the working condition when brake is not performed, as the Opening A of brake valve is
opened, the pump joint is interlinked with the joint of steering unit, and steering is in normal
service: When brake pedal is not pushed down, it will not generate brake even if steering is
operated. At this point, the oil pressure in oil pressure chamber D under control will not rise,
as B Opening is closed.
(2) Commencement and Completion of Brake Working Condition
A. When brake pedal is pushed down, the piston assembly 10 moves leftwards, and the valve
sleeve 7 and the recoil piston 5 are pressed towards the left side by spring unit, while the
return spring 6 is compressed towards left side at the same time along with.
B. Due to the movement of part 7, place A is closed, and D and the joint of oil tank are
disconnected. B will be opened accordingly, for D chamber and the pump joint to be
interlinked.
C. At this point the valve sleeve 7 moves further leftwards, place C allows the oil pressure of
pump joint and D chamber to rise due to compression, namely the oil pressure leading to
brake wheel cylinder will rise as well along with, at the same time the relatively higher oil
pressure in D chamber will push the recoil piston 5 rightwards, and this thrust force and the
pedal force are mutually balanced.
D. When maximum pedal force is entered on the right end of piston, bolt and pedal bracket
are used for limitation, in order not for the oil pressure in D chamber to exceed the maximum
adjusting oil pressure.
E. Release the foot from the pedal, the counterforce of recoil piston as well as the spring
counter forces of parts 6 and 8 will reset the valve sleeve 7 to its original position, and the
braking process is completed.
(3) Energy Accumulator Working Process
When oil pump stops work (for flameout of engine) or is damaged, it is required for energy
accumulator to enter into the working status.
A. When brake pedal is further pushed down, the valve sleeve 7, the recoil piston 5, and the
one-way valve contact pin 3 will move together leftwards, the contact pin will eject the ball,
and at this point D chamber and the joint of energy accumulator are connected, to play a
braking function to the brake wheel cylinder by using the pressure oil of energy accumulator .
B. Release the foot from the pedal, the valve sleeve, the recoil piston, and the contact pin will
move rightwards at the same time, the ball of one-way valve will recover its connection with
valve seat (one-way valve closed) under the action of spring force, while the contact pin shall
stop at this position.
C. Recoil piston moves rightwards, and the place C is opened, for the oil of brake wheel
cylinder of the brake to return to oil tank through D chamber.
Summary of Contents for FD100T
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