Huawei WR 22SA - Manual (Page 12)

11
English
before further wear developes. Matching socket and
bolt sizes are shown in Table 1.
The numerical value of a socket designation denotes
the side to side distance (S) of its hex hole.
5. Holding the tool
Hold the Impact Wrench firmly with both hands by
the body handle and the side handle. In this case
hold the wrench in line with the bolt.
It is not necessary to push the wrench very hard.
Hold the wrench with a force just sufficient to
counteract the impact force.
6. Confirm the tightening torque
The following factors contribute to a reduction of
the tightening torque. So confirm the actual
tightening torque needed by screwing up some
bolts before the job with a hand torque wrench.
Factors affecting the tightening torque are as follows.
(1) Line voltage:
The tightening torque decreases when the line
voltage becomes low (See Fig. 4).
(2) Operating time:
The tightening torque increases when the operating
time increases. But the tightening torque does not
increase above a certain value even if the tool is
driven for a long time (See Fig. 4).
(3) Diameter of bolt:
The tightening torque differs with the diameter of
the bolt as shown in Fig. 4. Generally a larger
diameter bolt has a larger tightening torque.
(4) Tightening conditions:
The tightening torque differs according to the torque
ratio; class, and length of bolts even when bolts
with the same size threads are used. The tightening
torque also differs according to the condition of the
surface of metal through which the bolts are to be
tightened.
(5) Using optional parts:
The tightening torque is reduced a little when an
extension bar, universal joint or a long socket is
used.
(6) Clearance of the socket:
A worn or deformed hex or a square-holed socket
will not give an adequate tightness to the fitting
between the nut or anvil, consequently resulting in
loss of tightening torque.
Using an improper socket which does not match
to the bolt will result in an insufficient tightening
torque. Matching socket and bolt sizes are shown
in Table 1.
MAINTENANCE AND INSPECTION
1. Inspecting the socket
A worn or deformed hex or a square-holed socket
will not give an adequate tightness to the fitting
between the nut or anvil, consequently resulting in
loss of tightening torque. Pay attention to wear of
socket holes periodically, and replace with a new
one if needed.
2. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure
that they are properly tightened. Should any of the
screws be loose, retighten them immediately. Failure
to do so could result in serious hazard.
3. Maintenance of the motor
The motor unit winding is the very “heart” of the
power tool.
Exercise due care to ensure the winding does not
become damaged and/or wet with oil or water.
4. Inspecting the carbon brushes
For your continued safety and electrical shock
protection, carbon brush inspection and replacement
on this tool should ONLY be performed by a Hitachi
Authorized Service Center.
5. Replacing supply cord
If the supply cord of Tool is damaged, the Tool
must be returned to Hitachi Authorized Service
Center for the cord to be replaced.
6. Service parts list
A: Item No.
B: Code No.
C: No. Used
D: Remarks
CAUTION
Repair, modification and inspection of Hitachi Power
Tools must be carried out by a Hitachi Authorized
Service Center.
This Parts List will be helpful if presented with the
tool to the Hitachi Authorized Service Center when
requesting repair or other maintenance.
In the operation and maintenance of power tools,
the safety regulations and standards prescribed in
each country must be observed.
MODIFICATION
Hitachi Power Tools are constantly being improved
and modified to incorporate the latest technological
advancements.
Accordingly, some parts (i.e. code numbers and/or
design) may be changed without prior notice.
NOTE
Due to HITACHI’s continuing program of research and
development, the specifications herein are subject to
change without prior notice.