Hitachi WR 12DH, Инструкция по эксплуатации и правила безопасности

Страница: 16 / 76

English
16
䡬
The rotational speed can be controlled by varying the amount that the trigger switch is
pulled. Speed is low when the trigger switch is pulled slightly and increases as the trigger
switch is pulled more.
NOTE
A buzzing noise is produced when the motor is about to rotate; this is only a noise, not
a machine failure.
7. Tightening and loosening bolts
A hex socket matching the bolt or nut must first be selected. Then mount the socket on
the anvil, and grip the nut to be tightened with the hex socket. Holding the wrench in line
with the bolt, press the power switch to impact the nut for several seconds.
If the nut is only loosely fitted to the bolt, the bolt may turn wit the nut, therefore mistaking
proper tightening. In this case, stop impact on the nut and hold the bolt head with a
wrench before restarting impact, or manually tighten the bolt and nut to prevent them
slipping.
8. Number of bolt tightened possible (with one charge (EB12B))
Please refer to the table below for the number of bolt tightened possible with one charge.
These values may vary slightly, according to surrounding temperature and battery
characteristics.
OPERATIONAL CAUTIONS
1. Cautions on use of the speed control switch
This switch has a built-in, electronic circuit which steplessly varies the rotation speed.
Consequently, when the switch trigger is pulled only slightly (low speed rotation) and the
motor is stopped while continuously driving in screws, the components of the electronic
circuit parts may overheat and be damaged.
2. Tightening torque
Refer to Fig. 8, 9 and 10 for the tightening torque of bolts (according to size), under the
conditions shown in Fig. 11. Please use this example as a general reference, as tightening
torque will vary according to tightening conditions.
Tightening torque varies, depending on the battery’s charge level. Fig. 12 shows an
example of the relationship between tightening torque and the number of tightenings,
for a 9/16
″ ×
2
″
(M14
×
50) high tension bolt. As shown, tightening torque gradually
weakens with the increase in the number of tightenings. In particular, as the torque
decreases very close to the complete discharge (“a” margin in graph), the unit’s impact
weakens, the number of time impacts declines and tightening torque drops off abruptly.
If this occurs, check torque level, then recharge the battery if necessary.
NOTE
䡬
If a long striking time is used, screws will be strongly tightened. This may cause the screw
to break, or may damage the end of the bit.
䡬
If the unit is held at an angle to the screw being tightened, the head of the screw may be
damaged, or the specified torque may not be transmitted to the screw. Always keep the
unit and the screw being tightened in a straight line.
Bolt used No. of tightenings
High tension bolt 15/32
″ ×
1–3/4
″
(M12
×
45) Approx. 130