Bosch GDS 18 V-EC 250 Original Instructions Manual page 14

14 | English
Removing the battery
The battery (4) is equipped with two locking levels to pre-
vent the battery from falling out when pushing the battery re-
lease button (5)unintentionally. As long as the battery is in-
serted in the power tool, it is held in position by means of a
spring.
To remove the battery (4), press the release button (5) and
pull the battery forward and out of the power tool. Do not
use force to do this.
Changing the Tool (see figure A)
Remove the battery from the power tool before carry-
u
ing out work on the power tool (e.g. maintenance,
changing tool, etc.). The battery should also be re-
moved for transport and storage. There is risk of injury
from unintentionally pressing the on/off switch.
Regularly clean the power tool's air vents. The motor's
u
fan will draw the dust inside the housing and excessive
accumulation of powdered metal may cause electrical
hazards.
When working with an application tool, ensure that
u
the application tool is connected securely to the tool
holder. If the application tool is not securely connected to
the tool holder, it can come off during operation.
Slide the application tool (10) onto the square drive of the
tool holder (1).
Due to the way the system operates, the application tool
(10) will move around slightly in the tool holder (1); this has
no influence on the function/safety.
Operation
Method of Operation
The tool holder (1) (with the application tool) is driven by an
electric motor via a gear and impact mechanism.
The working procedure is divided into two phases:
Screwing in and tightening (impact mechanism in action).
The impact mechanism is activated as soon as the screwed
connection runs tight and load is therefore put on the motor.
The impact mechanism then converts the power of the mo-
tor to steady rotary impacts. When loosening screws or nuts,
the process is reversed.
1 609 92A 4PN | (12.10.2018)
Starting Operation
Inserting the Battery
Set the rotational direction switch (6) to the centre position
to protect the power tool from being switched on accident-
ally.
Push the charged battery (4) into the base of the power tool
from the front until the battery is securely locked.
Set the rotational direction (see figure B)
The rotational direction switch (6) is used to change the ro-
tational direction of the power tool. However, this is not pos-
sible while the on/off switch (7) is being pressed.
Right rotation: To drive in screws and tighten nuts, press
the rotational direction switch (6) through to the left stop.
Left Rotation: To loosen and unscrew screws and nuts,
press the rotational direction switch (6) through to the right
stop.
Switching on/off
To start the power tool, press and hold the on/off switch
(7).
To switch off the power tool, release the on/off switch (7).
Adjusting the Speed
You can adjust the speed of the power tool when it is on by
pressing in the on/off switch (7) to varying extents.
A light pressure on the on/off switch (7) results in a low rota-
tional speed. Increased pressure on the switch causes an in-
crease in speed.
Practical advice
Only apply the power tool to the screw/nut when the
u
tool 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 impact. Maximum torque is
achieved after an impact duration of 6–10 seconds. After
this duration, the tightening torque is increased only minim-
ally.
The impact duration is to be determined for each tightening
torque required. The tightening torque that is actually
achieved should always be checked with a torque wrench.
Screw applications with hard, spring-loaded or soft seats
When the achieved torques in an impact series are measured
during a test and transferred into a diagram, the result is the
curve of a torque characteristic. The height of the curve cor-
responds to the maximum achievable torque, and the steep-
ness indicates the time in which this is achieved.
A torque characteristic depends on the following factors:
– 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 connection
Consequently, the following applies in each case:
– A hard seat is used for metal-to-metal screw applications
that use washers. The maximum torque is achieved after
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