Working Advice - Bosch GDR 10,8-LI Professional Original Instructions Manual

OBJ_BUCH-1066-001.book Page 20 Thursday, December 3, 2009 9:10 AM
20 | English
Battery Charge-control Indication
The battery charge-control indicator 10 consists
of three green LEDs, and indicates the charge
condition of the battery for a few seconds when
the On/Off switch 9 is pressed halfway or fully.
LED
Continuous lighting 3 x green
Continuous lighting 2 x green
Continuous lighting 1 x green
Flashing light 1 x green
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 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.
2 609 140 699 | (3.12.09)
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
Capacity
with the maximum reachable torque, and the
steepness indicates the duration in which this is
≥ 2/3
achieved.
≥ 1/3
A torque gradient depends on the following fac-
< 1/3
tors:
Reserve
– 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