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Scotch yoke actuators are a type of pneumatic or hydraulic actuator used primarily for automating quarter-turn valves such as ball valves, butterfly valves, and plug valves. Their distinctive design converts linear motion from a piston into rotational motion, using a “scotch yoke” mechanism. This design enables the actuator to deliver high torque output at the beginning and end of the stroke—where it's needed most to overcome valve breakaway and seating resistance.

Key Features

Scotch yoke actuators are specifically designed to deliver maximum torque at the beginning and end of the stroke—where valve resistance is typically highest. This makes them ideal for applications where valves are infrequently operated or have tight shutoff requirements.

Key Features

Engineered with robust materials and precision components, these actuators are built to handle harsh industrial environments. Their durable design ensures consistent performance over long operational cycles with minimal maintenance.

Key Features

Available in pneumatic and hydraulic models with both double-acting and spring-return configurations, Scotch yoke actuators can be tailored to suit a wide range of process conditions. They also support various accessories such as positioners, solenoids, and limit switches for complete valve control.

Scotch yoke actuators operate using a clever mechanical principle that transforms linear motion into rotary motion, making them ideal for quarter-turn valve automation. The core of this mechanism lies in the unique "scotch yoke" design, which allows for efficient torque distribution—particularly high at the start and end of the stroke. These torque peaks are critical for overcoming valve breakaway resistance and achieving tight shutoff.

At the heart of a scotch yoke actuator is a central shaft connected to a yoke, which is in turn driven by a piston. When pneumatic or hydraulic pressure is applied, the piston moves linearly along the cylinder. This motion pushes or pulls the yoke, which is slotted and engages with a pin or roller attached to the actuator shaft. As the yoke moves, it forces the shaft to rotate—usually 90 degrees—thus opening or closing the connected valve.

One of the key benefits of this design is the non-linear torque output. Unlike rack and pinion systems that deliver a more constant torque, the scotch yoke design concentrates torque at the critical points of valve operation: the breakaway (start) and seating (end) positions. This makes them highly effective in demanding applications where extra torque is needed during tight sealing or when valves haven’t been operated for long periods.

Scotch yoke actuators are available in double-acting configurations—where air or hydraulic pressure is used to power both opening and closing strokes—or spring-return versions, where the spring automatically returns the actuator to its fail-safe position in the event of pressure loss. They are also modular in design, allowing easy integration with a range of accessories such as solenoid valves, positioners, and limit switch boxes for full control and monitoring.

The scotch yoke design used by Air Torque provides a mechanical advantage by generating higher torque during the critical breakaway and seating phases of valve operation. This makes them especially effective where valves are hard to operate or require enhanced control under pressure. Air Torque actuators are built with quality materials, offering long service life and low maintenance requirements even in tough environments.

Pneumatic Pressure Range:	10bar Standard, 210bar (Hydraulic Version)
Torque Range:	60000Nm Double Acting, 30000Nm Spring Return
Temperature Range:	Standard (-40 - 80°C), High Temperature (-15 - 150°C), Low Temperature (-60°)

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With a compact footprint and modular design, Bettis actuators offer easy integration and maintenance. Their scotch yoke mechanism ensures optimal torque delivery throughout the stroke—particularly during valve breakaway and seating. Available in both pneumatic and hydraulic versions, Bettis actuators support a wide range of accessories including positioners, limit switches, and fail-safe systems, making them a reliable choice for critical applications.

Torque Output:	2,289,200Nm
Certificates:	ABS, ATEX, CCOE, CE, CSA, EAC, FM, IECEx, NACE, PED, SIL, INMETRO...

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Biffi Scotch Yoke Actuators are designed to deliver reliable and efficient valve automation in some of the most demanding industrial environments. Known for their precision engineering and robust construction, these actuators provide high torque output while maintaining smooth and consistent operation throughout the entire stroke.

They are available in both pneumatic and hydraulic versions, with options for double-acting and spring-return configurations. The scotch yoke mechanism ensures optimal torque performance at critical points of valve movement, making them particularly effective for tight shut-off and high-cycle duties.

Function:

Quarter Turn, Multi Turn & Linear

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V-Tork Scotch Yoke Actuators are built for high-torque valve automation in some of the most demanding industrial environments. With a rugged modular design and reliable performance at the core, these actuators are well-suited for applications requiring powerful, efficient quarter-turn motion such as ball, butterfly, and plug valves.

The VTS Series from V-Tork utilises a scotch yoke mechanism to provide superior torque output during breakaway and seating phases—exactly where it’s needed most. Designed for longevity and minimal maintenance, these actuators feature wear-resistant components and heavy-duty housings that ensure durability in harsh conditions.

Function:

Quarter Turn, Multi Turn & Linear

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A Scotch yoke actuator is a mechanical device that converts linear motion from a piston into rotary motion to operate quarter-turn valves. It uses a unique yoke mechanism to produce high torque at both the start and end of the stroke.

The actuator’s piston moves linearly, pushing or pulling a sliding yoke connected to a rotating shaft. This design delivers more torque where it's needed most—during valve opening and closing phases.

Scotch yoke actuators are typically used on quarter-turn valves such as ball valves, butterfly valves, and plug valves. They are ideal for valves with high torque or tight shutoff requirements.

They are commonly used in oil and gas, petrochemical, water treatment, power generation, and other heavy-duty industrial applications.

Key benefits include high torque output, efficient force distribution, rugged durability, and a design that suits valves with infrequent operation or tight sealing.

Yes, they come in both pneumatic and hydraulic versions. Each can be further configured as double-acting or spring-return based on application needs.

Double-acting actuators use air or hydraulic pressure to move in both directions. Spring-return models use pressure to move in one direction and a spring to return the actuator when pressure is lost.

Yes, many models are available with ATEX, SIL, and other certifications, making them suitable for use in explosive or safety-critical environments.

Common accessories include solenoid valves, positioners, limit switch boxes, manual overrides, and travel stops for enhanced control and feedback.

Scotch yoke actuators provide higher torque for the same cylinder size and are better suited for heavy-duty or high-torque applications. Rack and pinion actuators are more compact and better for general-purpose use.

They are designed for long-term durability with minimal maintenance. However, periodic inspection and lubrication may be needed depending on the operating environment and cycle frequency.

Scotch yoke actuators are usually made from high-grade aluminum, carbon steel, or stainless steel, depending on the application and environment. Internal components are often treated or coated for added corrosion and wear resistance.

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