Datasheet
184
SAFETY, ACTUATORS
System design
• CAutIoN!
1. Pneumatic cylinders can often be linked with
other moving parts, this must be taken into ac-
count when designing a system. If an external
force causes a sudden movement on the part
that is joined to the cylinder, the movement can
cause danger of injury.
2. If the cylinder is mounted directly adjacent to
an area where humans are present, use some
form of protective cover for the moving parts.
The system should have a design where pos-
sible, that isolates the moving parts.
3. Ensure that any brackets are carefully tted
with the necessary tools and proper torque.
This is especially important in systems where
strong vibrations occur which may cause the
machine parts to loosen.
4. When a cylinder handles a heavy load, or when
the speed is high, the built-in cushioning may
not be enough. For these cases a throttle cir-
cuit is recommended, that reduce the kinetic
energy when the actuator nears its end posi-
tions, or shock absorbers. Shock absorbers
can either be placed directly on the cylinder or
externally elsewhere in the machine construc-
tion.
5. Be aware that the system can consume an un-
natural high amount of air for a short time, that
can cause a pressure drop. This pressure drop
can cause the gripping tools, fastening cylin-
ders or other type of holding tools to drop the
object they handle. If the equipment handles
lifting movements, this is very important. In
some cases it may be necessary to integrate a
special safety circuit whose sole purpose is to
ensure that the cylinder always has access to
the required pressure so its safety is not com-
promised.
6. When one of an actuators working chambers
is exhausted, and the other is pressurized to
normal system pressure, the starting speed
is always high when the controlling valve is
switched. Ensure therefore that the working
speed is adapted to the movement it is intend-
ed to perform, and that the velocity isn’t too
high and causes personel injury.
Use the soft start valve EAV.
7. If the compressed air system has an emergen-
cy stop function, ensure that moving parts like
actuators always get exhausted, except when
the actuator itself has an important safety fea-
ture. It is also important to take into account
what happens when re-prezzurising the sys-
tem after an emergency stop. An emergency
stop can cause actuators to stop in unnatural
positions, with re-continued movement after
re-start, without regard to other safety features.
Manual safety valves can be used to return
the actuators to the normal position. For other
information about emergency stop Functions,
see EN-418; Machine safety – emergency stop
equipment, functional aspects – construction
principles.
Selecting appropriate
components
• DANGeR!
1. Ensure the cylinder technical data and other
specications. Products shown in this catalog
are designed for use in compressed air sys-
tems in industrial applications. If the product
is used in cases where its use is outside the
current specication, the product’s function is
compromised with the risk of personal injury
as a result. Contact SMC if you are in doubt or
if you believe that the application conditions
are beyond the current specication or if the
product should be used with a media, it isn’t
intended for.