Bosch GDR Professional Manual Original página 16

16 | English
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 can 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.
Inserting the application tool
GDR 18 V-160:
Pull the locking sleeve (2) forward, guide the application tool
(1) into the tool holder up to the stop and release the locking
sleeve (2) to lock the application tool.
Only use screwdriver bits with ball catch (9) (DIN 3126-
E6.3). Other screwdriver bits (11) can be inserted using a
universal bit holder with ball catch (10).
GDX 18 V-180:
Slide the application tool (12) onto the square drive of the
tool holder (1).
Due to the way the system operates, the application tool
(12) will move around slightly in the tool holder (1); this has
no influence on the function/safety.
Removing
Pull the locking sleeve (2) forward and remove the applica-
tion tool.
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.
Starting Operation
Inserting the Battery
Set the rotational direction switch (5) to the centre position
to protect the power tool from being switched on accident-
ally.
Push the charged battery (3) into the base of the power tool
from the front until the battery is securely locked.
Set the rotational direction (see figure C)
The rotational direction switch (5) is used to change the ro-
tational direction of the power tool. However, this is not pos-
sible while the on/off switch (6) is being pressed.
Right rotation: To drive in screws and tighten nuts, press
the rotational direction switch (5) through to the left stop.
1 609 92A 4PW | (25.10.2018)
Left Rotation: To loosen and unscrew screws and nuts,
press the rotational direction switch (5) through to the right
stop.
Switching on/off
To start the power tool, press and hold the on/off switch
(6).
The lamp (7) lights up when the on/off switch (6) is lightly or
fully pressed, meaning that the work area is illuminated in
poor lighting conditions.
To switch off the power tool, release the on/off switch (6).
Adjusting the Speed
You can adjust the speed of the power tool when it is on by
pressing in the on/off switch (6) to varying extents.
A light pressure on the on/off switch (6) 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 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 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 with the maximum reachable torque, and the
steepness indicates the duration in which this is achieved.
A torque gradient 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
The following application cases result accordingly:
– A hard seat is a metal-to-metal screw application which
uses washers. After a relatively short impact duration, the
maximum torque is reached (steep characteristic curve).
Unnecessary long impact duration only causes damage to
the machine.
– A spring-loaded seat is also a metal-to-metal screw ap-
plication but uses spring washers, disc springs, studs or
screws/nuts with conical seats. It is also called a spring-
loaded seat when extensions are used.
– A soft seat is a screw application of e.g. metal on wood or
a screw application that uses lead washers or fibre wash-
ers as backing.
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