Hitachi NR 90AC3, Технические данные и руководство по обслуживанию

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(4) Single actuation mechanism/contact actuation mechanism: (Fig. 9 and Fig. 10)
Single/contact actuation mechanism changeover is accomplished by turning the switching device
(Change Knob [50]).
Single actuation mechanism (Switching device:
upward position):
1) Immediately after driving the first nail, the
control valve should be as shown in Fig. 8.
2) When only Pushing Lever (B) [33] is released
and Trigger (A) [47] is held as shown in Fig. 9,
the plate of Trigger (A) [47] contacts the
Change Knob [50] and Plunger (A) [61]
returns (lowers) only halfway.
Because of this, compressed air does not flow
into the valve piston lower chamber, and
Valve Piston (B) [57] remains in the lowered
position. Accordingly, the Piston [19] remains
in the lowered position as shown in Fig. 7.
3) When Trigger (A) [47] is released, Plunger (A)
[61] returns (lowers) completely as shown in
Fig. 6. Compressed air then flows into the
valve piston lower chamber, and Valve Piston
(B) [57] is forced upward. The Piston [19]
then returns fully upward. Therefore, unless
Trigger (A) [47] is released after each nailing
operation, the structural mechanism prevents
the next nailing operation.
Contact actuation mechanism (Switching device:
downward position):
1) Immediately after the first nail is driven, the
control valve should be as shown in Fig. 8.
2) Even when only Pushing Lever (B) [33] is
released and Trigger (A) [47] is held, Plunger
(A) [61] returns (lowers) completely as shown
in Fig. 10. Thus the Piston [19] returns
(raises) fully. Accordingly, continuous nailing
can be accomplished by pushing only Pushing
Lever (B) [33] up and down while holding
Trigger (A) [47] depressed.
Plate
Plunger (A) [61]
Pushing Lever (B) [33]
Valve piston
lower chamber
Trigger (A) [47]
Valve Piston (B) [57]
Accumulator
Switching device (Change Knob [50])
(Upward position)
Fig. 9 Single actuation mechanism
Plunger (A) [61]
Pushing Lever (B) [33]
Valve piston
lower chamber
Trigger (A) [47]
Valve Piston (B) [57]
Accumulator
Switching device (Change Knob [50])
(Downward position)
Fig. 10 Contact actuation mechanism