ROHM OV / OVS - oil-operated cylinders - Manual (Page 8)

1. Qualification of Operating Personnel
Personnel inexperienced in the handling of clamping equip-
ment may be in particular danger of injury from the clamping
actions and forces as a result of inappropriate conduct, espe-
cially during set-up work.
For this reason the clamping devices may only be operated,
set-up or repaired by personnel with special training or with
many years of experience in this field.
2. Danger of Injury
For technical reasons this assembly may contain individual
parts with sharp edges. Always proceed with utmost caution
when working with the assembly to prevent the risk of injury!
2.1 Contained forces
Moving parts pre-tensioned with pressure springs, ten-
sion springs or any other springs or elastic elements
constitute a potential danger due to the forces they con-
tain. Underestimation of these forces can cause serious
injury resulting from uncontrollable, flying components
travelling at the speed of projectiles. Prior to executing
any further tasks, these contained forces must be relea-
sed. For this reason the respective assembly drawings
must always be procured prior to dismantling such a
device and such potential hazards detected.
Should the discharge of such contained forces not be
possible without any potential hazard, such elements
should only be dismantled by authorised RÖHM person-
nel.
2.2 Exceeding the Permissible Speed
This unit is designed for live operation. The centrifugal
forces resulting from excessive speeds or rotational
speeds may result in individual parts becoming detached
and constituting a potential danger for personnel or ob-
jects in the vicinity. This also applies to rotary seals,
which can cause a drop in pressure in the cylinder cham-
bers if they are subjected to excessive wear.
Operation at higher speeds than those specified for this
device is not permissible for the above-mentioned re-
asons.
The maximum speed and operating force/pressure are
engraved on the body and may not be exceeded. There-
fore the maximum speed of the machine used should not
be higher than that of the cylinder/oil distributor and must
therefore be limited.
Exceeding permissible values even once can cause da-
mage and constitutes a latent source of danger, even if
this is not immediately apparent. In such cases the ma-
nufacturer must be notified immediately so that the func-
tionality and operational safety of the device can be
checked. Only then can the continuing safe operation of
the device be ensured.
2.3 Lubrication
Dry operation of the distributor is not permitted.
If rotation of the clamping cylinder/oil distributor is initia-
ted, ensure that a minimum media pressure is supplied
to the connections (5 bar min.).
Pronounced wear must otherwise be expected on the
distributor gaps which can cause failure of the torsional
protection. A possible result could be that the pressuri-
sed connection lines are torn off.
2.4 Filtering the supplied medium
A pressure filter to remove foreign bodies from the hy-
draulic oil must be installed. We recommend installing
the filter on the hydraulic unit between the pump and the
control valve.
The absolute filter gauge must be 0.01 mm.
Inadequate filtering can have the same consequences as
described in section 2.3 (Lubrication).
2.5 Coolant Filtering
In the case of hollow clamping cylinders with a coolant
chip tray, chips can be flushed with the coolant into the
coolant chip tray and clog the drain. This can cause the
fluid level to rise so high that the coolant leaks into the
bearings, thereby destroying them. To avoid this, the
used coolant must be filtered and the coolant chip tray
has to be cleaned from time to time.
If the hollow clamping cylinder passage is not needed,
this should be sealed either on the chuck side or the cy-
linder side on the index plate.
2.6 Torsional protection on the distribution housing
The distribution housing must always be secured against
turning. This safety turn pin is to be attached at the lea-
kage oil connection.
Note:
Experience has shown that a fork-shaped holder is
particularly effective which encompasses the lea-
kage oil connection on both sides with minimum
clearance and which features an axial slot to com-
pensate for expansion and tolerances. This holder is
generally secured to the spindle housing.
2.7 Connection lines
No additional external forces, except the unit weight,
should be exerted on the distributor housing/shaft. This
would cause premature wear on the bearings and the
distributor gap with the consequences described in sec-
tion 2.3 (Lubrication).
For this reason all connection lines must be flexible and
should therefore all be hoses.
2.8 Tightening and replacing screws
In the event that screws are loosened or replaced, dan-
ger to personnel or equipment can result from inade-
quate replacement or tightening. If not expressly stated
otherwise, the tightening torque recommended by the
screw manufacturer and which is suitable for the screw
quality must be applied to all securing screws.
The values in the tightening torque table apply to the
standard sizes M5 -- M24 in the qualities 8.8, 10.9 and
12.9.
When replacing the original screws the quality 12.9
should be used if in doubt. The quality 12.9 must always
be used for cylinder covers and comparable elements.
The threads and head contact surfaces of all securing
screws which are frequently released and retightened
due to their application (e.g. for retooling) must be coated
with a lubricant (grease paste) at six-monthly intervals.
Even securely tightened screws can become loose under
adverse outside conditions such as, for instance, vibra-
tions. In order to prevent this happening, all safety-rela-
ted screws (clamping fixture fastening screws), clamping
set fastening screws etc.) must be checked and, if ne-
cessary, tightened at regular intervals.
2.9 Safety valves
In the event of a power failure (e.g. electric power sup-
ply) the safety valves must prevent loss of pressure,
which would release the clamping device. It must, howe-
ver, be pointed out that, due to the reaction times or seal
wear, a pressure loss of approx. 20% of the output pres-
sure of hydraulic cylinders may be experienced.
In unfavourable circumstances and despite the fact that
safety valves have been fitted this can lead to a situation
where the residual clamping force is no longer sufficient
to retain the workpiece in the clamping device.
Safety instructions and guidelines for the use of
oil-operated cylinders
17571-k001-001 26.10.2004 10:53 Uhr Seite 6