Hitachi NR 90AC3, Технические данные и руководство по обслуживанию

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8-3. Operation Principle
(1) Before nailing (See Fig. 5 and Fig. 6.)
1) When compressed air is fed to the main body, it
fills the accumulator ( portion).
2) At the same time, the compressed air flows into
the valve piston lower chamber of the control valve
section and forces Valve Piston (B) [57] upward.
Compressed air is then fed through the air supply
vent and air passage to the head valve chamber.
As a result, the Head Valve Spring [8] is pushed
down to seal the Head Valve [10] and Cylinder
[17].
(2) When nailing (See Fig. 4 and Fig. 5.)
1) When Pushing Lever (A) [37] and Trigger (A) [47]
are operated together and Plunger (A) [61] is
pushed upward, the compressed air in the valve
piston lower chamber is discharged from the
bottom of Plunger (A) [61]. As a result, the
compressed air in the accumulator ( portion)
pushes down Valve Piston (B) [57], blocking the air
supply vent and opening the exhaust valve.
2) When the exhaust valve opens, the compressed
air in the head valve chamber is discharged into
the atmosphere through the air passage.
3) When the air pressure on the bottom surface of the
Head Valve [10] overcomes the strength of the
Head Valve Spring [8], the Head Valve [10] is
pushed upward. At this time, the Head Valve [10]
seals with the Exhaust Valve Rubber [7], blocking
the passage to the exhaust vent.
4) When the Head Valve [10] goes up, the
compressed air in the accumulator flows rapidly
into the Cylinder [17], forcing the Piston [19]
downward to strike the nail. When the Piston [19]
passes the cylinder hole, the compressed air flows
into the return air chamber and is accumulated
there.
Fig. 6 Control valve section
Fig. 5
Head valve chamber
Nail
Air passage
Control
valve
section
Cylinder hole
Head Valve
Spring [8]
Exhaust vent
Exhaust Valve Rubber [7]
Head Valve [10]
Cylinder [17]
Return air
chamber
Pushing Lever (A) [37]
Piston [19]
Accumulator
Trigger (A) [47]
To the head valve chamber
Plunger (A) [61]
Valve Piston (B)
[57]
Valve piston lower chamber
Exhaust
valve
Air passage
Accumulator
Air supply vent