Hitachi Koki WF 4H2 Instrucciones De Manejo página 12

English
7. Mode switching feature (Fig. 17)
The screw driver has a mechanism for switching modes,
allowing it to output pressure in two steps to suit the
conditions with diff erent materials. The Normal mode has
little recoil, so works well when the fi nish is important,
while the Power mode is for jobs that require powerful
tightening.
Application
Gypsum board + wood studs
Plywood + wood studs
0.4 mm or less
Steel studs
0.4 – 0.6 mm
(Thickness)
0.6 – 0.8 mm
NOTE
○ Disconnect the air hose before switching modes.
○ Clean and oil the area around the mode lever periodically.
○ We recommend using the Normal mode with steel studs
if possible and using the Power mode if screws are not
penetrating far enough.
Take particular note that the Power mode cannot be used
with 0.4 mm steel studs. Always use the Normal mode.
Screws may pierce too far and strip out the metal or they
may not hold the material.
○ When using the Normal mode, if the materials are too
hard and screws are not getting tight, switch to the Power
mode.
○ When driving screws into plywood in the Power mode,
hold the body of the driver fi rmly with both hands to keep
it from shaking. (Fig. 18)
If the driver vibrates, the bit may lose contact with the
screw and fail to tighten it.
○ When starting work in the Normal mode, the driver may
not start properly on the fi rst try. If this happens, switch
the mode lever to Power mode temporarily and after two
or three screws, switch back to the Normal mode and use
it.
○ When in the normal mode, the pressure inside the high-
pressure screw driver is essentially the same all the time,
regardless of the pressure on the air compressor side.
Consequently, even if the pressure on the air compressor
side is raised, the pressure inside the driver does not
change.
○ The screw driver may not perform well when used in the
cold.
8. Relief valve (Fig. 19)
The relief valve is a mechanism that functions when the
pressure inside the driver exceeds 10 bar, expelling air out
of the exhaust port and decreasing the pressure inside the
driver.
The relief valve is inside the exhaust port.
When using the high pressure screw driver, if the relief valve
should operate and leak air, take the following steps to stop
the leak.
(If the air leak does not stop on the fi rst try, repeat steps 1
to 3 several times.)
1 Immediately disconnect the air hose.
2 Wait until the air compressor's pressure returns to 17.6
bar or more.
3 Reconnect the air hose.
12
○: can be used
×
: cannot be used
Normal Mode Power Mode
○ ○
×
○
○ ○
×
○
CAUTION
○ Put the dust cap on the air plug when not using the screw
driver or during breaks from work.
If dirt or dust from drywall gets into the screw driver via
the air plug, it may reduce the ability of the high-pressure
reducing valve to seal.
○ When not in use or during breaks from work, always
disconnect the air hose.
If you leave the air hose connected when the ability of the
high-pressure reducing valve is compromised, over time
air will leak little by little from the air hose (high pressure)
into the screw driver, raising the pressure inside it, which
may cause the relief valve to actuate.
○ Make a habit of draining the water inside the air
compressor.
If foreign matter such as rust in the drain gets inside the
high-pressure reducing valve, it will reduce its ability to
seal.
The high-pressure screw driver is equipped with a high-
pressure reducing valve that reduces the pressure from
the high pressure air hose side at 17.6 to 22.6 bar to a
normal pressure (about 8.2 bar). If debris gets inside this
high-pressure reducing valve, it reduces its ability to seal
properly and in such a state, if an air hose is left attached
for a long time, the pressure inside the screw driver will
rise gradually. This will eventually actuate the relief valve,
allowing air to leak violently from the exhaust port.
REPLACING THE BIT
If the bit starts losing contact with the screw frequently during
fastening, (bit fails to engage with the head of the screw,
spins out and fails to tighten the screw) it is time to change
the bit. Replace with a new part as soon as possible.
Use the bit changing tool that comes with the driver and
replace the bit as follows.
CAUTION
Always disconnect the air hose and unload all the screws
when changing the bit.
NOTE
○ Make sure no powder, dust or debris gets inside the
screw driver while changing the bit.
Such foreign matter can damage the screw driver.
○ Bits are consumable parts. If you continue to use a
worn bit, it may become impossible to replace it due
to damage to the bit's cross or to internal parts. At the
same time, work effi ciency suff ers and screws fail to be
fastened properly. Replace worn bits with new ones as
soon as possible.
1. Removing the bit
(1) Disconnect the air hose.
CAUTION
The bit cannot be replaced unless the air hose is
disconnected.
(2) Open the screw guide.
Open the vertical guide, insert the tip of the bit changing
tool in the muzzle and align it to the cross on the tip of the
bit. (Fig. 20)
(3) While pressing the bit changing tool against the bit, turn it
counterclockwise about 10 turns until the bit is detached
from inside the screw driver. (Fig. 21)
(4) Take the bit changing tool out, lower the muzzle, open
the vertical guide and the bit can be removed. (Fig. 22)