Working Advice - Bosch GDR 10,8 V-LI Professional Notice Originale

OBJ_BUCH-241-003.book Page 10 Thursday, October 22, 2009 10:13 AM
10 | English
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 power light 4 lights up when the On/Off
switch 8 is slightly or completely pressed, and
allows the work area to be illuminated when
lighting conditions are insufficient.
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.
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.
Temperature Dependent Overload Protection
When using as intended for, the power tool can-
not be subject to overload. When the load is too
high or the allowable battery temperature range
of 0–70 °C is exceeded, the speed is reduced.
The power tool will not run at full speed until
reaching the allowable battery temperature.
Protection Against Deep Discharging
The lithium ion battery is protected against
deep discharging by the "Electronic Cell Protec-
tion (ECP)". When the battery is empty, the ma-
chine is switched off by means of a protective
circuit: The inserted tool no longer rotates.

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
1 609 929 T13 | (22.10.09)
impact. The maximum torque is achieved after
an impact duration of 6–10 seconds. After this
duration, 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.
– A spring-loaded seat is given for metal-to-
metal screw applications, however with the
use of spring washers, disc springs, studs or
screws/nuts with conical seat as well as
when using extensions.
– A soft seat is given for screw applications,
e. g., metal on wood or when using lead
washers or fibre washers as backing.
For a spring-loaded seat as well as for a soft
seat, the maximum tightening torque is lower
than for a hard seat. Also, a clearly longer im-
pact duration is required.
Bosch Power Tools