Maintenance And Inspection - Hitachi dv 20vc Bedienungsanleitung

5. Selecting the appropriate drill bit
When boring concrete or stone
Use the drill bits specified in the Optional
Accessories.
When boring metal or plastic
Use an ordinary metalworking drill bit.
When boring wood
Use an ordinary woodworking drill bit.
However, when drilling 6.5 mm or smaller holes,
use a metalworking drill bit.
6. Confirm the direction of bit rotation (Fig. 5)
The bit rotates clockwise (viewed from the rear
side) by pushing the R-side of the reversing switch
lever. The L-side of the lever is pushed to turn the
bit counterclockwise. (for DV20VB only)
CAUTION
Always use the impact drill with clockwise rotation,
when using it as an impact drill.
7. Fixing the side handle (Fig. 6)
Loosen the wing bolt on the side handle, and attach
the side handle to the gear cover in a position
convenient for drilling. Match the projecting part of
the handle to the groove on the gear cover, and
firmly tighten the wing bolt. To remove the side
handle, loosen the wing bolt and rotate the handle.
To attach a depth gauge on the side handle, insert
the gauge into the U-shaped groove on the side
handle, adjust the position of the depth gauge in
accordance with the desired depth of the hole, and
firmly tighten the wing bolt.
8. IMPACT to ROTATION changeover (Fig. 7)
The Impact Drill can be switched from IMPACT
(impact plus rotation) to ROTATION (rotation only)
by turning the change lever. When boring concrete,
stone, tile or similar hard materials, turning the
change lever to IMPACT side. The drill head impacts
against the material while continuing to rotate.
When boring metal, wood or plastic, turning the
change lever to ROTATION side. The drill rotates
as an ordinary electric drill.
CAUTION
Do not use the Impact Drill in the IMPACT
function if the material can be bored by rotation
only. Such action will not only reduce drill
efficiency, but may also damage the drill tip.
The change lever may not turn smoothly when
changing from impact drill mode to drill mode.
(Fig. 7)
In this case, switch ON and operate the machine
for few seconds.
The spindle shaft will then be pushed forward,
and the change lever can be moved smoothly.
9. High-spped/Low-speed changeover
To change speed, rotate the gear shift dial as
indicated by the arrow in Fig. 8. The numeral "1"
engraved on the drill body denotes low speed, the
numeral "2" denotes high speed.
PRACTICAL HANDLING PROCEDURES
1. Speed adjustment and switch operation
The drill speed can be adjusted from 0 through full
speed by regulating the trigger-squeezing force.
The more the trigger is squeezed, the faster the drill
rotates. When the trigger is squeezed fully, the
speed is the maximum. (for DV20VB and DV20VC)
Pulling the trigger switch and pushing the stopper,
keeps the switched-on condition which is convenient
for continuous running. When switching off, the
stopper can be disconnected by pulling the trigger
again.
2. When using as a Drill or an Impact Drill
(1) Pressing force of the drill
You cannot drill holes more quickly even if you
press the drill with a stronger force than necessary.
It not only damages tip of drill bit and decreases
the efficiency of operation, but also shortens the
life of the drill tip.
(2) In case of penetrating holes
Drill bits can be broken when the material being
drilled is penetrated. It is important to decrease
pressing force just before penetrating.
CAUTION
In continuous operation, conduct no-load operation
for five seconds after completing a drilling job.
(3) When a thick drill bit is used
Your arm is subjected to larger reaction force when
a thicker drill bit is used. Be careful not to be moved
by the reaction force. For this, establish a foothold,
hold the unit tightly with both hands perpendicularly
to the material being drilled.

MAINTENANCE AND INSPECTION

1. Inspecting the drill bit
Continued use of a worn and/or damaged drill bit
will result in reduced drilling efficiency and may
seriously overload the drill motor. Inspect the drill
bit frequently and replace it as necessary.
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 (Fig. 10)
The motor employs carbon brushes which are
consumable parts. Since an excessively worn carbon
brush can result in motor trouble, replace the carbon
brushes with new ones having the same carbon
brush No. shown in the figure when they become
worn to or near the "wear limit". In addition, always
keep carbon brushes clean and ensure that they
slide freely within the brush holders.
5. Replacing carbon brushes: (Fig. 11)
Disassembling:
(1) Loosen the three screws on the handle cover, and
remove the handle cover.
(2) Lift out the brush holders together with the carbon
brushes, while being very careful not to forcibly pull
the lead wires within the brush holders.
(3) Withdraw the brush terminals, and remove the
carbon brushes from the brush holders.
Reassembling:
(1) Place new carbon brushes into the brush holders,
and connect the brush terminals to the carbon
brushes.
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