ROHM KZZT / KZZT-A - Power operated pulling collet chucks - Handbuch (Seite 9)

2.8 Fastening and replacing screws
If screws are replaced or loosened, defective replace-
ment or fastening may lead to a hazard for persons and
objects. For this reason, the corresponding torque re-
commended by the manufacturer for the screw and the
screw quality has to be used for all fastening screws as a
matter of principle, unless explicitly stated otherwise.
The following torque table shall be applicable for all stan-
dard sizes M5 to M24 of quality 8.8, 10.9 and 12.9:
In case of doubt, use screw quality 12.9 to replace the
original screw. As a matter of principle, quality 12.9 shall
be used for all fastening screws on clamping inserts, top
jaws, positive stops, cylinder covers, and comparable
elements.
All fastening screws, which on account of their useful
purpose have to be unscrewed and tightened again sub-
sequently (e.g. for refitting work), have to be covered
with an anti--seize agent (grease paste) in the thread
area and the head contact area in intervals of six
months.
2.9 Maintenance work
The reliability of the clamping equipment can only be
ensured if the maintenance specifications in the opera-
ting manual are strictly observed. Please observe in par-
ticular:
Use the lubricant recommended in the operating instruc-
tions for lubrication (unsuitable lubricant may reduce the
chucking force by more than 50 per cent).
-- In case of manual lubrication, please make sure that all
surfaces to be lubricated are reached (The narrow pas-
sages of the built--in parts require a high injection pres-
sure. For this reason, it is advisable to use a high--pres-
sure grease gun).
-- For good distribution of the grease in manual lubrica-
tion, move the internal moving parts to their final posi-
tions several times, re--lubricate them, and subsequently
check the chucking force.
-- For good distribution of the grease when a central lubri-
cation system is used, the lubrication pulses should be
set to the open phase of the clamping device.
Prior to series production and between the maintenance
intervals a chucking force measuring instruments has to
be used to check the chucking force. ”It is only a regular
check that ensures ideal safety”. It is advisable to move
the internal moving elements to their final position seve-
ral times after five hundred clamping actions at the latest
(Any lubricant pressed away will thus be returned to the
contact surfaces. Thus the chucking force is retained for
a longer period of time).
After a collision of the clamping unit, it has to be subjec-
ted to a crack detection prior to any further operation.
III. Hazards to the environment
The operation of clamping equipment partly requires the
use of various media for lubrication, cooling, et cetera.
As a rule these media are fed to the clamping equipment
through the distribution housing. The most frequently
used media are hydraulic fluid, lubricating oil or grease,
and coolant. When operating the clamping unit, these
media have to handled with care so that they do not get
on the ground and/or into the water. Warning ! Environ-
mental hazard !
This applies especially
-- for the assembly / disassembly as residual amount
may still be in the pipes, piston chambers and/or oil drain
screws
-- for porous, defective or incorrectly mounted seals
-- for lubricants which escape and/or are ejected from the
clamping equipment during operation for design reasons
For this reason, these escaping substances should be
collected and re--used or should be disposed of accor-
ding to the relevant regulations !
IV. Safety requirements on power clamping equipment
1. The machine spindle may not start until the clamping
pressure has been reached in the clamping cylinder and
clamping action has been effected within the permissible
working range.
2. The tension may be relieved only when the machine
spindle is at a standstill.
3. In case the clamping energy fails, a signal has to shut
down the machine spindle immediately.
4. In case the clamping energy fails, the work piece has
to remain safely clamped until the machine spindle has
come to a standstill.
5. In case of a power failure and subsequent power re-
turn, no changes of the switch position may occur.
Safety instructions and guidelines for the use of
power-operated clamping equipment
Tightening torques in Nm:
Class M5 M6 M8 M10 M12 M14 M16 M18 M20 M22 M24
8.8 5,9 10,1 24,6 48 84 133 206 295 415 567 714 Nm
10.9 8,6 14,9 36,1 71 123 195 302 421 592 807 1017 Nm
12.9 10 17,4 42,2 83 144 229 354 492 692 945 1190 Nm