Hitachi NT 65GB Technical Data And Service Manual page 15

2) Holding down the Trigger [71] makes
the spark switch turn on. The spark
plug in the combustion chamber then
discharges (Fig. 6).
The fuel thus burns and a sudden
expansion occurs. The Piston [27] is
then lowered to drive nails (Fig. 7).
When the Piston [27] passes the
hole of Cylinder Ass'y (A) [104A],
combustion gas is partially released
into the atmosphere through the
Reed Valve [50]. Because the
Reed Valve [50] is a non-return
valve, no air enters Cylinder Ass'y
(A) [104A]. When the Piston [27]
contacts the Piston Bumper [28],
the combustion of fuel is almost
completed.
(3) During return
Piston Ring (B) [17] seals the Chamber
[16] to cut off the atmosphere (Fig. 7).
Because combustion gas is partially
released into
through the Reed Valve [50], the
pressure at the upper portion of the
Piston [27] becomes lower than the
atmospheric pressure. The Piston [27]
is returned to its initial position by the
difference in pressure between the
upper and lower portions of the
Piston [27].
Hole of Cylinder
Ass'y (A) [104A]
the atmosphere
Hole of Cylinder
Ass'y (A) [104A]
Spark
Plug (A) [5]
Combustion
chamber
Piston [27]
Piston
Bumper [28]
Piston [27]
-12-
Spark switch
Trigger [71]
Fig. 6
Fig. 7