Working Advice - Berner BACIS 10,8V BL Originalbetriebsanleitung

OBJ_BUCH-2730-001.book Page 17 Tuesday, November 24, 2015 11:56 AM
Preselecting the Speed/Impact Rate
With the button 6 you can preselect the required
speed/impact rate in 2 stages. Press the button 6
repeatedly until the desired setting appears in the
speed indicator 5. The selected setting will be
saved.
The required speed/impact rate depends on the
material and the working conditions, and can be
determined through practical testing.
Switching the "PowerLight" On/Off
To switch the "PowerLight" 3 on, press button 4.
To switch the "PowerLight" 3 off, press button 4
again.
Battery Charge-control Indication
The battery charge-control indicator 11 consists of
three green LEDs, and indicates the charge condi-
tion of the battery for a few seconds when the
On/Off switch 10 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
In normal conditions of use, the power tool cannot
be overloaded. If the power tool is overloaded or
not kept within the permitted battery temperature
range, the power output is reduced or the power
tool is switched off. The power tool will not run at
full power output again until the permitted battery
temperature has been reached.

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 impact.
Reference Values for Maximum Screw/Bolt Tightening Torques
Calculated from the tensional cross-section; utilization of the yield point 90 % (with friction coefficient
= 0.12). As a control measure, always check the tightening torque with a torque wrench.
μ
total
Property Classes Standard Screws/Bolts
according to DIN 267
3.6
M 6 2.71
M 8 6.57
M 10
1 609 92A 1RK • 24.11.15
Capacity
≥ 2/3
≥ 1/3
< 1/3
Reserve
4.6 5.6 4.8
3.61 4.52 4.8
8.7 11 11.6
13 17.5 22 23
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
A test in which the achieved torques in an impact
series are measured and transferred to a diagram
will produce the curve of a torque characteristic.
The height of the curve corresponds with the max-
imum reachable torque, and the steepness indi-
cates 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 connec-
tion
The following application cases result accordingly:
– A hard seat is given for metal-to-metal screw ap-
plications with the use of washers. After a rela-
tively 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 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 ex-
tensions.
– 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 impact duration is
required.
6.6 5.8 6.8 6.9
5.42 6.02 7.22 8.13
13.1 14.6 17.5 19.7
26 29 35 39
High-strength Bolts
8.8 10.9 12.9
9.7 13.6 16.2
23 33 39
47 65 78
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