Maintenance And Inspection - Hitachi Koki WH 14DMR Instrucciones De Seguridad Y Manual De Instrucciones

3. Use a tightening time suitable for the screw
The appropriate torque for a screw differs according to the material and size of the screw, and the material
being screwed etc., so please use a tightening time suitable for the screw. In particular, if a long tightening
time is used in the case of screws smaller than 5/16" (8 mm), there is a danger of the screw breaking, so
please confirm the tightening time and the tightening torque beforehand.
4. Work at a tightening torque suitable for the bolt under impact
The optimum tightening torque for nuts or bolts differs with material and size of the nuts or bolts. An
excessively large tightening torque for a small bolt may stretch or break the bolt. The tightening torque
increases in proportionate to the operation time. Use the correct operating time for the bolt.
5. Holding the tool
Hold the impact wrench firmly with both hands. 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) Voltage
When the discharge margin is reached, voltage decreases and tightening torque is lowered.
(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.
(3) Diameter of bolt
The tightening torque differs with the diameter of the bolt. Generally a larger diameter bolt requires 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 workpiece
through which the bolts are to be tightened. When the bolt and nut turn together, torque is greatly reduced.
(5) Using optional parts (Impact wrench)
The tightening torque is reduced a little when an extension bar, universal joint or a long socket is used.
(6) Clearance of the socket (Impact wrench)
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.
CAUTION:
Pull out battery before doing any inspection or maintenance.
1. Checking the condition of the bit (Impact driver)
The bits should be checked regularly. If worn or broken bits can slip or decrease the efficiency of the motor and burn it out.
Replace worn bits with new ones.
CAUTION:
If you use a driver bit of which point is worn or broken, it will be dangerous since it slips. So replace it with a new
one.
2. Checking the condition of the socket (Impact wrench)
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 a socket holes
periodically, and replace with a new one if needed.
3. Check the Screws
Loose screws are dangerous. Regularly inspect them and make sure they are tight.
CAUTION:
Using this power tool with loosened screws is extremely dangerous.
4. 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.

MAINTENANCE AND INSPECTION

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