Hitachi NT 65M2 Technical Data And Service Manual page 15

(4) Single actuation mechanism/contact actuation mechanism: (Fig. 8 and Fig. 9)
Single/contact actuation mechanism changeover is accomplished by turning the switching device
(Change Knob (C) [58]).
Single actuation mechanism (Switching device:
upward position):
1) Immediately after driving the first nail, the
control valve should be as shown in Fig. 7.
2) When only Pushing Lever (B) [40] is released
and Trigger (C) Ass'y [36] is held as shown in
Fig. 8, the plate of Trigger (C) Ass'y [36]
contacts Change Knob (C) [58] and the Plunger
[67] returns (lowers) only halfway.
Because of this, compressed air does not flow
into the valve piston lower chamber, and Valve
Piston [63] remains in the lowered position.
Accordingly, the Piston [12] remains in the
lowered position as shown in Fig. 6.
3) When Trigger (C) Ass'y [36] is released, the
Plunger [67] returns (lowers) completely as
shown in Fig. 5. Compressed air then flows into
the valve piston lower chamber, and the Valve
Piston [63] is forced upward. The Piston [12]
then returns fully upward. Therefore, unless
Trigger (C) Ass'y [36] 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. 7.
2) Even when only Pushing Lever (B) [40] is
released and Trigger (C) Ass'y [36] is held, the
Plunger [67] returns (lowers) completely as
shown in Fig. 9. Thus the Piston [12] returns
(raises) fully. Accordingly, continuous nailing
can be accomplished by pushing only Pushing
Lever (B) [40] up and down while holding
Trigger (C) Ass'y [36] depressed.
Plunger [67]
Switching device (Change Knob (C) [58])
(Upward position)
Fig. 8 Single actuation mechanism
Plunger [67]
Switching device (Change Knob (C) [58])
(Downward position)
Fig. 9 Contact actuation mechanism
--- 12 ---
Accumulator
Valve Piston [63]
Trigger (C)
Ass'y [36]
Valve piston
lower chamber
Accumulator
Valve Piston [63]
Trigger (C) Ass'y [36]
Valve portion
lower chamber
Pushing Lever (B) [40]