Rohm DURO-A, Translation Of The Original Operating Manual

Page: 42 / 52

7 | Maintenance
42 / 52 Power Chuck DURO-A
Activity Interval
Visually inspect wear parts. Weekly.
Visually inspect jaw screws.
Replace defective screws. Weekly.
Replace jaw screws. Annually.
Inspection of the power chuck.
See
Inspection of the Power
Chuck [ } 45] .
Annually or at the latest after 500,000
clamping cycles.
7.3 Maintenance Work
7.3.1 Checking the Tightness of Screw Connections
If screws are replaced or undone, incorrect replacement or incorrect attach-
ment may lead to dangers for persons and objects. For this reason, for all
holding screws, the tightening torque recommended by the manufacturer of
the screw must be applied in accordance with the screw grade.
For cylinder head screws of the conventional sizes M4 – M24 and strength
classes 8.8, 10.9 and 12.9, the following tightening torque table applies:
Tightening torque in Nm
Strength
class M3 M4 M5 M6 M8 M10 M12 M14 M16 M18 M20 M22 M24
8.8 1.27 3.0 5.9 10.1 24.6 48 84 133 206 295 415 567 714
10.9 1.79 4.6 8.6 14.9 36.1 71 123 195 302 421 592 807 1,01
7
12.9 2.14 5.1 10 17.4 42.2 83 144 229 354 492 692 945 1,19
0
The table values do not apply to tightening torques expressly specified
elsewhere!
When replacing the original screws, the strength class specified by the man-
ufacturer is to be observed. In the case of mounting screws for clamping
devices, clamping inserts, top jaws, rigid stops, pre-clamped covers, equal-
ising weights and comparable elements, strength class 12.9 is always to be
used.