How V-Tork Scotch Yoke Actuators Work
V-Tork Scotch Yoke Actuators operate using a mechanical principle that converts linear motion into rotary movement. Inside the actuator, a piston is driven by either compressed air (pneumatic) or hydraulic fluid. As the piston moves forward or backward within the cylinder, it pushes or pulls a sliding yoke mechanism.
This yoke is connected to a rotary shaft via a pin and slot system. As the piston travels, the yoke’s motion causes the shaft to rotate—typically 90°—to open or close a quarter-turn valve such as a ball, butterfly, or plug valve. The scotch yoke design delivers non-linear torque, meaning it produces maximum torque at the start and end of the stroke—precisely where valves require the most force to overcome static friction or tight shut-off seals.
In spring-return models, a heavy-duty spring compresses during one half of the stroke and then releases to return the actuator to its fail-safe position in the event of pressure loss. This makes them ideal for safety-critical applications.
The actuator body includes guide rails and bearings to ensure smooth piston movement and minimise wear, while the modular housing allows for the mounting of various accessories like solenoid valves, positioners, and limit switches. This combination of mechanical efficiency and flexible design makes V-Tork Scotch Yoke Actuators a powerful and practical solution for industrial valve automation.
