Maintenance And Service - Bosch GDR 14,4 V-LI Professional Notice Originale

OBJ_BUCH-832-007.book Page 18 Thursday, September 8, 2016 9:07 AM
18 | English
after an impact duration of 6–10 seconds. After this dura-
tion, 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 corre-
sponds with the maximum reachable torque, and the steep-
ness 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
Reference Values for Maximum Screw/Bolt Tightening Torques
Calculated from the tensional cross-section; utilization of the yield point 90 % (with friction coefficient μ
measure, always check the tightening torque with a torque wrench.
Property Classes Standard Screws/Bolts
according to DIN 267
3.6
M 6 2.71
M 8 6.57
M 10 13
M 12 22.6
M 14 36
M 16 55
Tips
Before screwing larger, longer screws into hard materials, it is
advisable to predrill a pilot hole with the core diameter of the
2
thread to approx. / of the screw length.
3
Note: Pay attention that no metal particles enter the power
tool.
Belt Clip
With the belt clip 4, the machine can be hung onto a belt. The
user has both hands free and the machine is always at hand.
Recommendations for Optimal Handling of the Battery
Protect the battery against moisture and water.
Store the battery only within a temperature range between
–20 °C and 50 °C. As an example, do not leave the battery in
the car in summer.
Occasionally clean the venting slots of the battery using a soft,
clean and dry brush.
A significantly reduced working period after charging indi-
cates that the battery is used and must be replaced.
Observe the notes for disposal.
1 609 92A 2CV | (8.9.16)
The following application cases result accordingly:
– A hard seat is given for metal-to-metal screw applications
with the use of washers. After a relatively short impact du-
ration, the maximum torque is reached (steep characteris-
tic curve). Unnecessary long impact duration only causes
damage to the machine.
– A spring-loaded seat is given for metal-to-metal screw ap-
plications, 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 back-
ing.
For a spring-loaded seat as well as for a soft seat, the maxi-
mum tightening torque is lower than for a hard seat. Also, a
clearly longer impact duration is required.
4.6 5.6 4.8 6.6
3.61 4.52 4.8 5.42
8.7 11 11.6 13.1
17.5 22 23 26
30 37.6 40 45
48 60 65 72
73 92 98 110

Maintenance and Service

Maintenance and Cleaning
 Before any work on the machine itself (e. g. mainte-
nance, tool change, etc.) as well as during transport
and storage, remove the battery from the power tool.
There is danger of injury when unintentionally actuating
the On/Off switch.
 For safe and proper working, always keep the machine
and ventilation slots clean.
Replacing the Carbon Brushes (see figure E)
Check the length of the carbon brushes approx. every
2–3 months and replace the carbon brushes if required.
Never replace only a single carbon brush!
Note: Use only carbon brushes supplied by Bosch and intend-
ed specifically for your product.
– Unscrew the caps 16 using a suitable screwdriver.
– Replace the spring-loaded carbon brushes 15 and screw
the caps back on again.
= 0.12). As a control
total
High-strength Bolts
5.8 6.8 6.9 8.8
6.02 7.22 8.13 9.7
14.6 17.5 19.7 23
29 35 39 47
50 60 67 80
79 95 107 130
122 147 165 196
10.9 12.9
13.6 16.2
33 39
65 78
113 135
180 215
275 330
Bosch Power Tools