Starting Operation; Working Advice - Bosch GDR Professional 14,4 V-LI Notice Originale

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The impact mechanism is activated as soon as
the screwed connection runs tight and thus load
is put on the motor. In this instance, the impact
mechanism converts the power of the motor to
steady rotary impacts. When loosening screws
or nuts, the process is reversed.

Starting Operation

Inserting the Battery
Use only original Bosch lithium ion batter-
ies with the voltage listed on the nameplate
of your power tool. Using other batteries can
lead to injuries and pose a fire hazard.
Set the rotational direction switch 7 to the cen-
tre position to protect the power tool against
accidental starting.
Insert the charged battery 5 from the front into
the base of the power tool until the battery is se-
curely locked.
Reversing the Rotational Direction
(see figure B)
The rotational direction switch 7 is used to re-
verse the rotational direction of the machine.
However, this is not possible with the On/Off
switch 8 actuated.
Right rotation: For driving in screws and tight-
ening nuts, press the rotational direction switch
7 through to the left stop.
Left Rotation: For loosening and unscrewing
screws and nuts, press the rotational direction
switch 7 through to the right stop.
Switching On and Off
To start the machine, press the On/Off switch 8
and keep it pressed.
The light 9 is lit when the On/Off switch 8 is
slightly or completely pressed in and permits to
light the work area when the lighting conditions
are bad.
To switch off the machine, release the On/Off
switch 8.
Adjusting the Speed
The speed of the switched on power tool can be
variably adjusted, depending on how far the
On/Off switch 8 is pressed.
Bosch Power Tools
Light pressure on the On/Off switch 8 results in
a low rotational speed. Further pressure on the
switch results in an increase in speed.

Working Advice

Apply the power tool to the screw/nut only
when it is switched off. Rotating tool inserts
can slip off.
The torque depends on the impact duration. The
maximum achieved torque results from the sum
of all individual torques achieved through im-
pact. The maximum torque is achieved after an
impact duration of 6–10 seconds. After this du-
ration, the tightening torque is increased only
minimally.
The impact duration is to be determined for
each required tightening torque. The actually
achieved tightening torque is always to be
checked with a torque wrench.
Screw Applications with Hard, Spring-loaded
or Soft Seat
When in a test, the achieved torques in an im-
pact series are measured and transferred into a
diagram, resulting in the curve of a torque char-
acteristic. The height of the curve corresponds
with the maximum reachable torque, and the
steepness indicates the duration in which this is
achieved.
A torque gradient depends on the following fac-
tors:
– Strength properties of the screws/nuts
– Type of backing (washer, disc spring, seal)
– Strength properties of the material being
screwed/bolted together
– Lubrication conditions at the screw/bolt con-
nection
The following application cases result accord-
ingly:
– A hard seat is given for metal-to-metal screw
applications with the use of washers. After a
relatively short impact duration, the maxi-
mum torque is reached (steep characteristic
curve). Unnecessary long impact duration
only causes damage to the machine.
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