Bosch GDR Professional Original Instructions Manual page 10

OBJ_BUCH-608-002.book Page 10 Monday, November 23, 2009 8:32 AM
10 | English
Operation
Method of Operation
The tool holder 1 with the tool is driven by an
electric motor via a gear and impact mechanism.
The working procedure is divided into two phas-
es:
Screwing in and tightening (impact mechanism
in action).
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 O-pack batteries
with the voltage given on the type plate of
your machine. The use of other batteries can
lead to injuries and danger of fire.
Set the rotational direction switch 8 to the cen-
tre position in order to avoid unintentional start-
ing. Insert the charged battery 5 into the handle
so that it can be felt to engage and faces flush
against the handle.
Reversing the Rotational Direction
(see figure B)
The rotational direction switch 8 is used to re-
verse the rotational direction of the machine.
However, this is not possible with the On/Off
switch 9 actuated.
Right rotation: For driving in screws and tight-
ening nuts, press the rotational direction switch
8 through to the left stop.
Left Rotation: For loosening and unscrewing
screws and nuts, press the rotational direction
switch 8 through to the right stop.
Switching On and Off
To start the machine, press the On/Off switch 9
and keep it pressed.
To switch off the machine, release the On/Off
switch 9.
1 609 929 T16 | (23.11.09)
Adjusting the Speed
The speed of the switched on power tool can be
variably adjusted, depending on how far the
On/Off switch 9 is pressed.
Light pressure on the On/Off switch 9 results in
a low rotational speed. Further pressure on the
switch results in an increase in speed.
Swivel Lighting System (see figure C)
Your tool is equipped with a light source in the
knurled thumbwheel 7. The light is activated as
soon as the knurled thumbwheel 7 is in position
1 – 3 and the On/Off switch 9 is pressed.
Depending on the bit being used, the light beam
can be adjusted to three positions by turning
the knurled thumbwheel 7. In position 1, the fo-
cus of the light beam is approx. 20 mm, in posi-
tion 2 approx. 150 mm and in position 3 approx.
500 mm in front of the tool holder 1.
In the "OFF" position, the light is switched off
permanently.
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.
Bosch Power Tools