What distinguishes a single-acting cylinder from a double-acting cylinder?

A single-acting cylinder is designed to apply force only on one side, which is why it is distinguished from a double-acting cylinder. In a single-acting cylinder, the actuation occurs when air or fluid pressure is applied to one side of the piston, causing it to move in one direction. The return motion typically relies on an external force, like a spring or gravity, to bring the piston back to its original position.

In contrast, a double-acting cylinder can exert force in both directions because it has ports on both sides of the piston. This means that pneumatic or hydraulic pressure can be applied to either side, allowing it to push and pull with equal efficiency. The ability to control movement in both directions is one of the key advantages of double-acting cylinders over single-acting ones.

Therefore, the defining characteristic of a single-acting cylinder is its limitation to applying force on only one side, which underscores its functionality in specific applications where a return mechanism is acceptable or advantageous.