Glossary · Pneumatics and hydraulics
Double-acting cylinder
Also known as: Double-acting actuator
German: Doppeltwirkender Zylinder
In fluid power, a double-acting cylinder is a cylinder in which fluid pressure can act on both sides of the piston, so it produces force and motion in both the extending and retracting directions.
- Fluid power
In one sentence
A double-acting cylinder uses fluid pressure on both sides of the piston to push and pull in both directions.
Example
A pneumatic clamp uses a double-acting cylinder so that both clamping and opening are powered and speed-controlled.
How it applies
- Engineering: Force on retraction is lower than on extension because the rod reduces the piston area. Speed is typically set with flow-control valves in the exhaust (meter-out).
- Commissioning: End-position cushioning and speeds are adjusted; sensors detect end positions.
- Operation: On loss of air, a double-acting cylinder may stay, drift or move, depending on the valve and load; there is no spring to return it.
- Documentation: Describe the behavior on loss of energy and after re-pressurization, when trapped air or empty chambers can cause sudden motion. Include a procedure to vent both chambers before maintenance.
Double-acting vs. single-acting cylinder
A Single-acting cylinder is powered in one direction and returns by spring or external force. A double-acting cylinder is powered in both directions.