Full definition
Single-acting cylinders are pneumatic actuators that apply pressure to one side of a piston, enabling linear motion in one direction. The return stroke is facilitated either by a compression spring or gravity, making these cylinders simpler and often more compact than their double-acting counterparts. The basic operational principle involves the force exerted by the compressed air (P) acting on the piston area (A), countered by the force of the spring (F_spring). This results in the equation for advance force: F_advance = P × A − F_spring. Consequently, single-acting cylinders are particularly suited for applications where the return stroke can be achieved without additional pneumatic input, thus minimizing air consumption and enhancing energy efficiency.
Typically, the stroke length of single-acting cylinders is limited by the length of the return spring, which usually ranges from 100 mm to 200 mm. When selecting a cylinder, it is crucial to consider the maximum stroke required for the application, as exceeding this distance may lead to a failure in the return mechanism. Common standards governing these cylinders include ISO 6432, which specifies mini cylinders with diameters between 8 mm and 25 mm, and ISO 15552, which covers larger cylinders with a more extensive range of diameters and stroke lengths.
Single-acting cylinders find applications in various industrial contexts, primarily in workpiece clamping, ejectors, and light assembly pressing operations. Their design allows them to be used where space is at a premium or where simplicity and reliability are paramount. For instance, in automated assembly lines, these cylinders can efficiently clamp components during assembly, ensuring high precision and reduced cycle times. Brands such as Festo (ESNU/DSN), SMC (CJP/CDQ2), Parker (P1A), and Norgren (RM/C series) offer a range of single-acting cylinders tailored for diverse operational requirements.