Rotary pneumatic actuators produce oscillating action by using compressed air or fluid power to turn a shaft in a predetermined arc of motion. Durability, efficiency, and compact size are hallmark’s of good actuator design. They are great for generating massive torque on demand, as needed, in a simple intelligent package.

Here are five common types of pneumatic actuator designs.

1. Helical spline – Helical splines going in both directions are housed in separate chambers. One produces clockwise rotation and the other returns the actuator to its starting position
2. Enclosed piston crank – Produces sinusoidal torque from a simple 100 degree shaft rotation
3. Scotch yoke – This is an enclosed piston crank with one rotational shaft controlling two pistons; one on either side. These actuators generate high breakaway torque.
4. Rack and pinion – Central toothed gear moves two pistons with constant and equal torque in both directions.
5. Piston chain – Two geared sprockets move pistons using a chain system. They can produce several complete rotations.

Methods to limit rotation include the use of bladders, electric actuators and vanes. Bladder driven actuators are highly accurate and almost any fluid medium can be used to operate them with rotation ranges between 90 and 180 degrees. Vane actuators come in two varieties, single and double. Single vane actuators typically have 280 degrees of rotation, while double vane actuators have about 100 degrees of motion.

There are many applications for rotary actuators. They include mixing, lifting, turning, positioning containers, and operating valves to name just a few. So if you need rotational motion to get the job done, actuators are just what you need.