Single-Acting Cylinders Pneumatic Controls

Design of a Single-Acting Cylinder

The following graphic shows the design of a single-acting cylinder with return spring and the relevant symbol according to DIN ISO 1219-1.


(1) Base
(2) Side of piston
(3) Cylinder tube
(4) Piston with piston rod and seal
(5) Side of rod
(6) Cover
(7) Exhaust
(8) Return spring
(9) Air inlet

If compressed air of pressure pis supplied to the cylinder via the air inlet, the piston surface A is subjected to a force of


The amount of mechanical work then performed is proportional to the stroke length 's'


Single-acting cylinders are only able to do work in one direction. This means they are suitable for charging, ejecting, pressing, lifting and feeding.

How the cylinder Works:

The following animation shows how a single-acting cylinder works.



Compressed air flows via the air-inlet into cylinder on the side of the piston, in the process of which pressure p builds up over the surface of the piston generating a force F that is proportional to the pressure. This pressure causes the piston and piston rod to move (extend). Once the piston has reached full extension, the pressure builds up to full operating pressure. After the pressure has fallen the reset spring restores the piston to its initial operating position (return action). As the force of the spring resists the motion during forward motion phase, it is only designed to be strong enough to return the piston back into its initial position and is thus normally unable to return any heavy items connected to the piston rods to their initial position. It is also important to keep the length of the stroke sufficiently restricted as otherwise the force of the spring would continue to increase the longer the stroke length becomes.

More From