The basic principle of single-acting cylinder is transferring the fluid or any output force to one direction only. So, the hydraulic fluid in the single-acting cylinder acts only on one side of the piston. Within a single-acting cylinder, the piston rod is pushed outwards but it cannot be pulled back. A force is required from the opposite direction to retract piston rod to its reset position. In application single-acting cylinders are complemented with another component that works as secondary source of force – this is done either by a internal spring of the cylinder or by a pump or a motor. As the single-acting cylinder works in unidirectional way they are used where either the push or the pull force is required and hence there are two types of single-acting cylinder that are available in the market – for push or pull. This is the reason single-acting cylinders are mostly used in reciprocating engines. Where the force generated by a single-acting cylinder is reciprocated by another cylinder or spring or gravitational force of the load for retraction of the piston rod.

There are many reasons for which single-acting cylinder is preferred over double-acting cylinders. As single-acting cylinders have a defined rest position it is considered fail safe. So, where safety is a major concern and hand-held machines are used single-acting cylinder is always preferred. In the single-acting cylinder the piston rod resets to a fixed position that is known by the operator and it is a safer option while operating the machine. Single-acting cylinders consumes less air in comparison to double-acting cylinder so it is more cost effective for operation. Machines with single-acting cylinder are precise and fail safe and hence they are easier to control. Single-acting cylinders are used where motion is required to be generated in one direction. Let us see in which jobs single-acting cylinders are mostly used:

• Single-acting cylinders are used for clamping. For example, a work piece can be drilled with a machine fitted with single-acting cylinder by holding the piece at a place. After drilling one piece the jaws of the drill retract to its reset position and the machine is ready for drilling the next piece.
• Single-acting cylinders are also used for positioning a product on a conveyor belt. Either for placing the piece on the belt or for pulling off the product from the belt. Once a product is pulled off the conveyor belt the piston rod retracts and gets ready for pulling off the next product.
• The thrust of a single acting cylinder is used to punch on an object or to mark a product. The piston is retracted to its reset position and the machine is ready for puncing the next product.

This is to be noted that all these jobs can be done by other types of cylinders as well. But with single acting cylinder they can be done with more precision and at a faster speed. With single acting cylinder these processes can be done in a safer and cost-effective manner as well.