A piston rod cylinder always has a piston rod with a drive piston, the movement of which is controlled by compressed air. The energy applied to the piston is then transferred by the piston rod to the parts to be moved. Cylinders with piston rod are available as double-acting and single-acting piston rod cylinders.
Single-acting cylinders with piston rod only have one supply port. The cylinder is supplied with compressed air via the port, causing the piston to move in one direction. When the cylinder releases the air again, the piston is returned to its initial position by a spring.
Double-acting cylinders, on the other hand, have two supply ports and are only actuated using compressed air. As compressed air is supplied to either port, it causes the cylinder to extend and retract.