Mechanism And Operation Principle; Mechanism - Hitachi NR 83A2 Technical Data And Service Manual

8. MECHANISM AND OPERATION PRINCIPLE

8-1. Mechanism

As illustrated in Fig. 3, the Model NR 83A2 can be generally divided into four sections:
output section, control valve section, driving section and magazine section.
The basic construction of the Model NR 83A2 is the same as that of the Model NR 83A and the interchangeable
components are used as much as possible. However, most of the parts of the control valve section have been
changed to provide the tool-less depth adjuster and the single actuation (single sequential actuation)/contact
actuation mechanisms in order to correspond to the modification of the ANSI standard and the market demands.
All the parts of the driving section and the magazine section have been newly designed. Primary differences from
the Model NR 83A are described below.
Output section ...........
Control valve section .... Following parts were changed or added owing to the change of the construction
Driving section ............ All the parts were newly designed.
Magazine section ........ The magazine and handle arm (B) were newly designed.
Body: Fixation of the magazine section was changed from two M5 bolts to one M8 bolt.
An air escape groove was provided at the inmost position of the trigger valve
bushing (see 8-2 (1) (2) for details). The bolt for mounting the nose was
changed from the hex. socket hd. bolt M8 x 25 to the nylock hex. socket hd. bolt
M8 x 22. The screw hole is therefore different in depth and the bolt for the
Model NR 83A cannot be used for the Model NR 83A2.
The grip tape wound around the handle was changed to the ring-type grip
rubber. (The grip rubber is common to the Model NR 83AA2. Conventional grip
tape is supplied as a repair part because the grip rubber cannot be mounted to
the body handle by hand.)
The cylinder was newly designed.
The exhaust valve was newly designed. {A hole (1 mm dia.) was provided to prevent
malfunction when selecting the single actuation (single sequential actuation)
mechanism.}
The bolts were changed to the bolts with washers and flanges (common to the Model
NR 83AA2).
(selectable either the single actuation mechanism or the contact actuation
mechanism).
Plunger (A) was newly designed.
Plunger (B) was newly designed.
The spring of Plunger (B) was newly designed.
The valve bushing was newly designed.
Valve sleeve (A) (switching device) was newly designed.
(This is a new part adopted in the Model NR 83A2 first.)
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