Hitachi NV 50AG2, Technical Data And Service Manual

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(1) Prior to nailing (Fig. 6)
1 When compressed air is supplied 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 pushes up the valve piston. Also, the
compressed air flows from the air supply vent,
through air passage (A), and into the head valve
upper chamber where it simultaneously pushes
down the head valve and the head valve spring to
seal the upper surface of the head valve and the
cylinder.
(2) During nailing (I) (Fig. 7)
1 When the plunger is pushed up by operating both
the pushing lever and the trigger, the compressed
air in the valve piston lower chamber is exhausted
from the lower part of the plunger. Then, the valve
piston is pushed down by the compressed air from
the accumulator ( ///// ) so that it shuts off the air
supply vent and released the exhaust valve.
2 When the exhaust valve opens, the compressed
air in the head valve chamber is exhausted into the
atmosphere through air passage (A).
3 The air pressure applied to the lower surface of the
head valve exceeds the force of the head valve
spring, and pushes up the head valve. The head
valve is pushed fully upward by the compressed
air, and seals the upper surface of the exhaust
cover and the head valve.
4 When the head valve is pushed up, the
compressed air flows rapidly into the cylinder and
pushes down the piston to drive a nail. At this
time, the compressed air flows through the cylinder
hole, into the return air chamber, through air
passage (B), and into the chamber at the left side
of the feed piston in the nail feeder section. When
the air pressure exceeds the force of the feed
spring, the feeder moves to the right.
7-2. Operation Principle
Cylinder
Head valve spring
Air passage (A)
Head valve
Accumulator
Valve piston
Control
valve
section
Air supply vent
Pushing lever
Fig. 6 Prior to nailing
Air supply vent
Fig. 7 During nailing (I)
Exhaust valve
Accumulator
Exhaust cover
Air passage (A)
Head valve spring
Head valve
Cylinder
hole
Piston
Cylinder
[Return air
chamber]
Air passage
(B)
Plunger
Trigger
Pushing lever
Valve piston
Nail feeder
section
Feed spring
Feed piston
Nail
feeder
Pushing lever