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21
Bosch Power Tools
1 609 929 W79 | (22/4/10)
Setting the Speed/Impact Rate
The electronic control enables stepless speed
and impact preselection in accordance with the
material to be worked.
The constant electronic control keeps the prese-
lected speed and impact rate nearly constant
between no-load and load conditions.
When plugging the plug into the socket outlet or
after a power failure, the constant electronic
control automatically sets the highest speed
and impact rate. This ensures working at opti-
mum performance despite too low preadjust-
ment of the thumbwheel
7
.
– Select the impact rate with the thumbwheel
7
according to the material.
The data in the following table are recommend-
ed values.
Safety Clutch
f
If the tool insert becomes caught or
jammed, the drive to the drill spindle is in-
terrupted. Because of the forces that occur,
always hold the power tool firmly with both
hands and provide for a secure stance.
f
If the power tool jams, switch the machine
off and loosen the tool insert. When switch-
ing the machine on with the drilling tool
jammed, high reaction torques can occur.
Changing the Chiselling Position (Vario-Lock)
The chisel can be locked in 12 positions. In this
manner, the optimum working position can be
set for each application.
– Insert the chisel into the tool holder.
– Turn the mode selector switch
3
to the
“Vario-Lock” position (see “Setting the Oper-
ating Mode”, page 20).
– Turn the tool holder to the desired chiselling
position.
– Turn the mode selector switch
3
to the “chis-
elling” position. The tool holder is now
locked.
f
The mode selector switch 3 must always be
locked in the “Chiselling” position when
chiselling.
Working Advice
f
Before any work on the machine itself, pull
the mains plug.
Vibration Damper
The integrated vibration damper reduces occur-
ring vibrations.
The soft grip handle increases the safety against
slipping off and thus provides for a better grip
and handling of the power tool.
Application
Thumbwheel
Position
Working roughcast/light
building materials
Removing tiles
Working brick
Working concrete
OBJ_BUCH-491-004.book Page 21 Thursday, April 22, 2010 1:32 PM
