Operational Cautions - Hitachi WR 22SA Manual De Instrucciones

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OPERATIONAL CAUTIONS

1. Confirm the line voltage (Fig. 4)
The available tightening torque is in-
fluenced by line voltage. Reduced line
voltage lowers the available tightening
torque.
For example, if you use a 120 V type
wrench on a 110 V line the available
tightening torque will be reduced to 70
to 90%. When extending the power
cord, use an extension cord which is
as short as possible. When the line volt-
age is low and a long extension cord is
needed a step up transformer should
be used. The relation between the line
voltage and the tightening torque are
shown in the figures.
2. 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.
3. Work at a tightening torque suitable for the bolt under impact
The optimum tightening torque for nuts and bolts differs 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.
4. 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 insufficient tightening but also in damage
to the socket or nut.
A worn or deformed hex. or square-holed socket will not give an adequate tight-
ness for fitting 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 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.
10
M22 × 70 (F10T)
ft–lbs (kg-m)
588(80)
514(70)
Rating 120V
440(60)
367(50)
294(40)
220(30)
0
0 2 4
Tightening time
Fig. 4
110V
6 8 10 (s)