Hitachi NR 90AC3, Technical Data And Service Manual

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8. MECHANISM AND OPERATION PRINCIPLE
8-1. Mechanism
As illustrated in Fig. 3, the Model NR 90AC3 can be generally divided into four sections:
Output section, control valve section, driving section and magazine section.
Although the basic construction of the Model NR 90AC3 is the same as that of the Model NR 90AC2 and
interchangeable components are used as much as possible, the Model NR 90AC3 is provided with the single
actuation (single sequential actuation)/contact actuation mechanisms in order to correspond to the modification of
the ANSI standard. The driving section and the magazine section are common to those of the Model NR 90AC2.
Primary differences from the Model NR 90AC2 are described below.
Output section .............. Body: Newly designed.
Control valve section .... Following parts were changed or added owing to the change of the construction
(selectable either the single actuation mechanism or the contact actuation mechanism).
Plunger (A): Newly designed (common to the Model NT 65MA2).
Valve piston (B): Newly designed (common to the Model NT 65MA2).
Trigger (A): Newly designed (common to the Model NT 65MA2).
Change knob (switching device): Added new parts.
Fig. 4 Construction
Exhaust vent
Adjuster (A) [34]
Cylinder [17]
Piston [19]
Piston Bumper (A)
[24]
Trigger (A)
[47]
Dust Filter [42]
Exhaust
Cover [5]
Body [22]
Cap [43]
Nail feeder ass'y
Magazine section
Driving section
Output section
Top Cover [3]
Exhaust Valve
Rubber [7]
Head Valve [10]
Accumulator
Piston Bumper (B)
[25]
Nose [30]
Pushing Lever (B)
[33]
Pushing Lever (A)
[37]
Control valve section
Plunger Spring [60]
Plunger (A) [61]
Valve Piston (B) [57]
Valve Bushing
(B) [54]
Valve Bushing
(A) [63]
Control valve section
Switching device
(Change Knob [50])