Operation Principle - Hitachi NR 90AC2 Technical Data And Service Manual

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 (
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) [54] 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) [46]
are operated together and Plunger (A) [58] is
pushed upward, the compressed air in the valve
piston lower chamber is discharged from the
bottom of Plunger (A) [58]. As a result, the
compressed air in the accumulator (
pushes down Valve Piston (B) [54], 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.
portion).
portion)
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Exhaust Valve Rubber [7]
Exhaust vent
Head Valve
Spring [8]
Head Valve [10]
Accumulator
Piston [19]
Cylinder hole
Cylinder [17]
Return air
chamber
Pushing Lever (A) [37]
To the head valve chamber
Air passage
Exhaust
valve
Valve piston lower chamber
Fig. 6 Control valve section
Head valve chamber
Air passage
Control
valve
section
Trigger (A) [46]
Nail
Fig. 5
Accumulator
Air supply vent
Valve Piston (B)
[54]
Plunger (A) [58]