Pneumatic Cylinders

PNEUMATIC CYLINDERS

          Drive Elements are Actuators – used to perform the task of exerting the required force at the end of the stroke or used to create displacement by the movement of the piston.
Pneumatic Actuators can be classified as :

•Single Acting Cylinders

Conventional Cylinder with Spring Loaded Piston or
Diaphragm type

•Double Acting Cylinders

Symbolic Representation of Pneumatic Cylinders -Linear Actuators

Pneumatic Cylinders

Single Acting Cylinder

•Single acting cylinder has one working port
•Forward motion of the piston is accomplished to due to supply of compressed air behind
the piston.
•Return motion of piston takes place only due to built in reset spring placed on the rod
side of the cylinder.
•Single acting cylinders are used for applications such as clamping, feeding, sorting,
locking, ejecting, braking etc., where force is required to be exerted only in one direction..
•Single acting cylinder are usually available in short stroke lengths [ maximum length up
to 80 mm] due to the natural length of the spring.
Single Acting Cylinder exert force only in one direction.

Single Acting Cylinder

Double Acting Cylinders

They are available in different constructions such as
•Conventional,
•Double ended piston rod type,
•Rod less type
•Tandem type
•Multi-position type and
•Rotary type.

Conventional Cylinders

•Double Acting Cylinders are equipped with two working ports- one on the piston side
and the other on the rod side.
•To achieve forward motion of the cylinder, compressed air is admitted on the piston side
and the rod side is connected to exhaust. During return motion supply air admitted at the
rod side while the piston side volume is connected to the exhaust. Force is exerted by the
piston both during forward and return motion of cylinder
•Double acting cylinders are available in diameters from few mm to around 300 mm and
stroke lengths of few mm up to 2 meters

Double Acting Cylinder Retracted and Advanced Positions

End Position Cushioning

•Pneumatic cylinders operates at much higher speeds than Hydraulic cylinders. Due to
this, there is a tendency of the piston to ram against the end covers as the piston
approaches the ends at high velocity especially in cylinder with large mass. This impact
force can damage the cylinder as well as the piston due to repetitive action .
•All Double acting cylinders excepting for small sizes, are provided with end position
cushioning arrangement.
•This arrangement decelerates the piston motion as it approaches the end of the stroke

Double Acting Cylinder With Cushions

Tandem Cylinder

•Tandem cylinder is essentially a combination of two cylinders in tandem such that force
derived from the first cylinder, supplements the force obtained by the second cylinder.
More or less the force produced by a tandem cylinder is as twice as that of a conventional
double acting cylinder of the same diameter.
•This type of cylinder is used where more force is to be generated and there is no scope
for increasing the diameter of cylinder due constraint of space

Tandem Cylinder

Rod less Cylinders

Different operational principals are used for the construction of Rod less cylinders:
1. Cable Cylinder
2. Sealing band Cylinder with slotted cylinder barrel
3. Cylinder with Magnetically Coupled Slide
Rod less cylinder have the following advantages:
•Available in long lengths –up to 4 m or even higher ( as there is no buckling)
•Most ideally suited for stopping and fixing (Robotic application)
•Occupies less space as the extension of piston rod is not present

Rod less Cylinder with Magnetic Coupling

This cylinder has a hermetically sealed arrangement where piston is housed inside a
sealed cylinder barrel. The piston is provided with number of annular ring magnets,
radially polarised. An external sleeve which slides over the cylinder, is also provided
with similar arrangement of ring magnets. Thus a magnetic coupling is established
between the piston and slider. As the piston reciprocates due to supply of compressed air,
the slider also reciprocates over the cylinder

Rod less cylinder with Magnetic coupling

In the next share pages, we will show you Rod Less Cylinder - Mechanically Coupled,
so stay on this page, thank you.