Operational Cautions - Hitachi WR 22SE Manual De Instrucciones

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OPERATIONAL CAUTIONS

1. Do not touch the bumper or hammer case during continuous operation
The bumper and hammer case become hot during continuous screw tightening so be careful
not to touch them at that time.
2. Work at a tightening torque suitable for the bolt under impact
The optimum tightening torque for nuts and bolts diff ers with material and size of the nuts and
bolts. An excessively large tightening torque for a small bolt may stretch or break the bolt. The
tightening torque increases proportionally to the operating time. Use the correct operating
time for the bolt.
3. Selecting the socket to be matched to the bolt
Be sure to use a socket which is matched to the bolt to be tightened. Using an improper
socket will result not only in insuffi cient tightening but also in damage to the socket or nut.
A worn or deformed hex. or square-holed socket will not give an adequate tightness for fi tting
to the nut or anvil, consequently resulting in loss of tightening torque.
Pay attention to wear of socket holes, and replace before further wear has develops. Matching
socket and bolt sizes are shown in Table 2.
The numerical value of a socket designation denotes the side-to-side distance (S) of its hex.
hole.
4. Holding the tool
Hold the Impact Wrench fi rmly 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 suffi cient
to counteract the impact force.
5. Confi rm the tightening torque
The following factors contribute to a reduction of the tightening torque. So confi rm the actual
tightening torque needed by screwing up some bolts before the job with a hand torque
wrench.
Factors aff ecting the tightening torque are as follows.
(1) Line voltage:
The tightening torque decreases when the line voltage becomes low.
(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. 6)
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