Scotch Yoke Pneumatic Actuator Working Principle

Scotch Yoke pneumaic actuators provide an efficient service and maintenance costs , which is quite low actuators between. Pneumatic actuators are among the efficient and reliable actuators that work with compressed air or gas . These actuators, which provide a high working speed and efficiency , are among the actuators that are very easy to install with their lightweight structure .

Maintenance and operating costs are very low. The costs during installation  maybe slightly higher than other actuators . A scotch yoke actuator can basically be described as an actuator that can transform a straight motion into a circular motion .

How Does a Scotch Yoke Actuator Work?

We can think of a linear motion as a forward and backward motion on a straight iron bar . We can imagine that the ends of this iron rod are attached to a yoke, one of which is attached to a rod and the other to a sliding block ahead. If force is applied to the piston , the sliding block moves in the seat of the yoke, causing the yoke to rotate in a circular manner.

A scotch yoke actuator converts a linear force into torque . It also makes the quarter turn, that is 90 degree turn valves, motorized. Scotch yoke actuators are also divided into two as single-acting and double-acting.

Single Acting Scotch Yoke Actuators

Single-turn or single- action scotch yoke actuators consist of three basic parts. One of them is the yoke mechanism, the others are the pressure cylinder and the spring. Deleted alive to when compressed air is applied to that section, straight movement is past the piston surface. Thanks to the movement of the sliding block in the yoke seat, a counterclockwise rotation occurs on the yoke and the valve is moved in the opposite direction.

Double-Acting Scotch Yoke Actuators

A double-acting or double-acting actuator does not contain a spring inside. This is the air pressure required for the actuator to be open or closed. It does not require a system that prevents errors in double acting pneumatic actuators . Pneumatic movement, that is, if the air pressure stops when it is made from any input, it works, if it works, it stops. Unlike the other, there are only two different entries.