China Scotch Yoke Actuator Manufacturers, Suppliers and Factory

Company Profile

ZHEJIANG BIGTORK VALVE AUTOMATION CO,.LTD was located in famous pump and valve manufacturer base--Wenzhou City, China since founded by Mr zhang in 2006. Bigtork® take part in domestic and oversea gas and oil project in 2011, and now have a extensive experience in industry valve automation and flow control. Company has signed framement agreement with SINOPEC and CNOOC as qualified Pneumatic Actuator supplier. Meanwhile, we are the reliable business partner of foreign world famous brand.

Why Choose Us?

Rich experience
BIGTORK not only focus on manufacturing Rotary & Linear and Pneumatic & Hydraulic valve actuator, but also offering one industry process control solution since founded by Mr zhang in 2006. We have 18+ extended production experience and 14+ extensive globle project undergo.

Strong R&D ability
Our team involves 6 engineers who owns domestic and oversea project work experience. We supply 100% technical support and problem solution for whole product life. Size selection tool that self owned software is avaivable for every clients.

Quality assurance
All series products strictly controlled with 9 processes by ISO and other system. The business partner of the raw material and components are profession major which supply for world renowned brand. A product warranty was provided with final testing and test report accordance with international product standards.

One stop service
Bigtork offer OEM & ODM services according to your requests from pre-sale to after-sale period. Each project has its own sale service tracking records. Each staffs is well trained to master proficient skill and full professional knowledge to support industry flow control one stop solution service.

Double-Acting P350Scotch Yoke Actuator
This scotch yoke pneumatic actuator adopts a high-output torque structural design and is suitable for automated opening and closing control of 90° rotary valves such as ball valves and butterfly valves. The actuator features a compact
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BG Series Scotch Yoke Actuator
The BG Series Scotch Yoke Actuator is a compact, high-torque, and reliable quarter-turn actuator designed specifically for the automated control of ball valves, butterfly valves, and plug valves.
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Spring Return Actuator
A spring return actuator utilizes stored spring energy to generate motion, enabling the controlled movement of air or fluid in a single direction to drive the piston. This action is used to precisely open or close the valve. The design is
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Double Acting Actuator
A double acting actuator is a sophisticated device designed to operate valves by applying force in both opening and closing movements. Unlike their single acting counterparts, which use a spring to return to the original position, double
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Air Actuator
An scotch yoke air actuator is a valve switch device can converts energy into compressed air into rotary mechanical motion to achieve the valve open and close. It mostly called scotch yoke pneumatic actuator. Bigtork® scotch yoke air
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Air Torque Actuator
BG series scotch yoke air torque actuator are designed in many different model number combinations of actuator sizes, cylinder diameters. The scotch and yoke actuator can provide a wide torque output range from 360Nm to 110000Nm, which the
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Air Pressure Actuator
Scotch yoke air pressure actuators are designed for use over a wide range of pressures or temperatures. BG series air pressure actuators use pressurize air or gas to move a piston back and forth, which is connected to an oscillating yoke
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Heavy Duty Actuator
The heavy duty actuator are available as pneumatic or hydraulic scotch yoke actuators for 90 degree angular valves, dampers or any device.BG series is accompanied by a complete sets of accessories modular, involving side-mounted handwheel,
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Actuator Scotch Yoke
Valve actuator scotch yoke type are 90˚ driving mechanisms that can be powered by compressed air or hydraulic oil from an external source to converts linear motion of a bar sliding back and forth into a rotational motion. Rotary actuator
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Single Acting Actuator
A single acting actuator have either air or liquid supplied to one side of the piston, and the energy to move the valve comes from a spring on the opposite side. The pressure of the air or liquid in the single acting actuator can opens or
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Double Acting Actuator
Double acting actuator has ports at each end of the actuator and can operates in both directions. Double acting actuator can have higher torque in specific situations than spring return actuators. This applies there is a need for very high
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Heavy Duty Rotary Actuator
The heavy duty rotary actuator are available as pneumatic or hydraulic scotch yoke actuators for 90 degree angular valves, dampers or any device.BG series is accompanied by a complete sets of accessories modular, involving side-mounted
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What is Scotch Yoke Actuator？

Scotch yoke actuators are mechanical devices used to automatically open and close valves or dampers. The scotch yoke is a mechanism that converts linear motion of a bar sliding back and forth into a rotational motion.

Benefits of Scotch Yoke Actuator

Compactness
Its compact design is advantageous in space-constrained applications.

Smooth output motion
The mechanism ensures a continuous acceleration and velocity profiles which help to minimize jerk and inertial loading.

Simplicity and reliability
Fewer moving parts mean easier manufacturing and maintenance, and often greater reliability.

High torque output:
One of the key advantages of a Scotch yoke actuator is its ability to deliver high torque output. The unique design of the Scotch yoke mechanism converts rotary motion into linear motion with a constant torque profile throughout the stroke. This consistent torque output makes it ideal for applications that require precise control and the ability to handle heavy loads effortlessly.

Versatile applications:
Scotch yoke actuators find extensive use in a wide range of applications. They are commonly employed in valve automation, where they provide precise control over the opening and closing of valves. These actuators can handle both linear and rotary valve motions, making them suitable for gate valves, globe valves, and other types of industrial valves. Additionally, Scotch yoke actuators are used in various other applications such as damper control, process control, and even in heavy machinery for linear motion tasks.

Enhanced safety features:
Safety is paramount in industrial environments, and Scotch yoke actuators are designed with this in mind. They often come equipped with features such as emergency shut-off capabilities, fail-safe options, and position feedback systems. These safety features ensure that the actuator can quickly respond to emergency situations, prevent equipment damage, and safeguard personnel.

Types of Scotch Yoke Actuator

1.Double acting scotch yoke actuators:

In the example below, air supplied at port 2 is released into the chamber and forces the piston towards the central module of the scotch yoke actuator, in turn performing the counterclockwise rotation through the scotch yoke mechanism and opening of the connected valve. Exhaust air is exited through port 4. To perform the closing operation air is supplied through port 4 from the central module of the actuator. Forcing the piston to the end of the body chamber and clockwise rotation is achieved. Exhaust air is exited through port 2.

2.Spring return scotch yoke actuators:

For Spring Return Scotch Yoke Actuators, air supplied at port 2 is released into the chamber and forces the piston towards the central module of the actuator, this compresses the spring in the opposite chamber and performs the counterclockwise rotational movement, opening the valve. Exhaust air is exited through port 4. Depressurisation to port 2 through the use of an intentional or non-intentional action allows the spring to move the piston back towards the opposite end of the air chamber and immediately closes the valve. Exhaust air is exited through port 2.

Application of Scotch Yoke Actuator

Industrial automation: Used in assembly lines for moving parts or products.

Material handling: For lifting and moving heavy materials in manufacturing and warehousing.

Machine tools: In CNC machines and other automated tools for precise positioning.

Medical equipment: In devices that require controlled linear motion, such as patient beds or surgical tables.

Agricultural machinery: For controlling the movement of plows, harvesters, and other farming equipment.

Automotive industry: In assembly lines for the precise placement of components.

Construction equipment: For controlling the movement of hydraulic rams in excavators and other heavy machinery.

Aerospace: In control systems for aircraft components and satellite deployment mechanisms.

Entertainment: In animatronics and other special effects for movies and theme parks.

Valve actuation: For opening and closing valves in fluid control systems.

Components of Scotch Yoke Actuator

Crank

The crank rotates around the fixed link as its centre point and the sliding pin as its endpoint.

Sliding pin

This sliding pin is a fixed link to the double slider crankshaft on the other side. It is also attached to a crank

Sliding yoke

The sliding yoke has a slot that attaches to a sliding pin that slides inside the sliding yoke.

Fixed link

When the crank rotates around the fixed link, the sliding pin slides into the slot of the yoke, and the yoke slides forward and backwards.

Connecting rod or piston

It achieves the output reprocessing motion of the scotch yoke mechanism. The piston or reciprocating part is added to a sliding yoke.

How to Maintain Scotch Yoke Actuator

Safety warnings and caution
Prior to maintenance work on the scotch and yoke actuator, it is necessary to disconnect all air and electrical supplies from actuator.
The recommended air pressure is given according to the design pressure in principle. If local conditions require higher pressure, an assessment should be performed. However, it is recommended that the maximum air pressure should be not more than 0.6MPa.
Ensure the service environment conditions are compatible with scotch and yoke actuators before installation.
The air supply shall be clean, use of non-corrosive components, compressed air or other gas as suitable.
●Attention: The spring sleeve and end covers provide protection structure of the spring assembly. Spring is pre-compressed and is always under pressure, the nuts and bolts securing this assembly should not be tampered with to avoid any accidents.
●Attention: Before any assembly/dissassembly work of the actuator, the operator shall make sure the actuator spring is not energized and the actuator air supply is shut off. Failure to do so may result in injuries.
●Attention: During mounting of an actuator on a valve, never insert your hand in the valve bore.
Due to heavy weight of the actuator, it is advisable to provide support in the middle of the spring cartridge at the installation site.
Air supply shall be clean, use of non-corrosive components, compressed air or other gas as suitable.
The air pressure is given according to the design pressure in principle. If local conditions require higher pressure, an assessment should be performed.
However, it is recommended that the maximum air pressure should be not more than 0.6MPa.
The spring sleeve and end covers provide protection structure of the spring assembly. Spring is pre-compressed and is always under pressure, the nuts and bolts securing this assembly should not be tampered with to avoid any accidents.
During inspection maintenance, ensure that the air supply is cut off and pressure is fully discharged.

Receiving and storage
Unloading
Actuators should be unloaded carefully. The actuators should be carefully lowered from the truck to the ground, not dropped. Only hoists and slings with adequate load capacity to handle the weight of the actuators should be used. Do not hook hoists into or fasten chains around by motors, cylinders, or hand wheels. Failure to carefully follow these recommendations is likely to result in damage to the actuators.

Storage
Actuators should be stored in the fully closed position to prevent entry of foreign material that could cause damage to the seating surfaces. Whenever practical, actuators should be stored indoors. If outside storage is required, means should be provided to protect operating mechanisms, such as gears, motor and cylinders, from weather elements. During outside storage, actuators should be protected from the weather, sunlight, ozone, and foreign material. In colder climates, where actuators may be subject to freezing temperatures, it is absolutely essential to remove water from the actuators interior and close the tightly before storage. Failure to do so may result in a cracked castings.

Store actuators so that no heavy loads are applied to the actuators body.

Inspection before installation
Actuators should be inspected at the time of receipt for damage in shipment. The initial inspection should verify compliance with specifications, directions of opening and size. Inspection personnel should look for broken hand wheels, cracked parts, loose bolts, missing parts and accessories, if applicable, and any other evidence of mishandling during shipment.

Inspection and maintenance
The scotch & yoke actuators are designed for long term maintenance-free service. Preventive maintenance shall be based on the actual operating conditions.

Actuators in stored for long period of time or with low operating cycles should be cycled at least once every 90 days.

Outside paints can be renewed if required based on environment conditions.

Internal seals should be every 3 to 6 years depending on the operating conditions.

How It Works

Gas supply: The gas-powered scotch yoke actuator uses pressurized gas as the driving force, which, depending on the specific application and site requirements, the gas source is a natural gas pipeline, an onsite compressor, or bottled gas.

Pneumatic cylinder: The gas enters the pneumatic cylinder, which is the core component of the actuator. The cylinder contains a piston that moves linearly when pressurized gas is applied.

Scotch yoke mechanism

The linear motion of the piston is converted into rotary motion using the scotch yoke mechanism. The scotch yoke consists of a yoke (a slotted, U-shaped component) attached to the piston rod and a pin mounted on the rotating output shaft. The yoke slides along the pin as the piston moves linearly, causing the output shaft to rotate.

Output shaft

The output shaft's rotation is transferred to the valve stem, causing the valve to open or close, depending on the direction of the rotation. The shaft is connected to the valve using a coupling, which ensures proper alignment and torque transmission.

Spring return mechanism

Some gas-powered scotch yoke actuators have a spring return mechanism, which enables the valve to return to a predetermined fail-safe position in the event of a loss of gas supply or system failure.

Rack and Pinion vs. Scotch-Yoke: When to Specify Which?

Torque profile needs:
For ball or butterfly valves that demand consistent torque throughout the rotation, rack, and pinion actuators are preferable.

The scotch-yoke design is advantageous for gate or globe valves that require high torque at the start and end of operation.

Space & weight considerations:
In constrained spaces or where weight is a concern, the compact nature of rack and pinion actuators may be beneficial.

Durability & maintenance:
In clean environments, the more straightforward design of the rack and pinion might have an edge in terms of longevity.

The wear and tear on the scotch-yoke's sliding parts may require more frequent maintenance in dirty or harsh conditions.

Cost sensitivity:
Budget constraints might lean towards rack and pinion actuators, though weighing initial costs against potential maintenance and longevity is essential.

Operational speed:
Depending on design specifics, speed requirements may favor one actuator type over the other.

Our Factory

Bigtork® have covered an area of total 20000 square meters, which its workshop for machining, assemble, testing and its warehouse for raw material, semi-finished product and finished product.

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Our Certificates

FAQ

Q: How does a scotch yoke actuator work?

A: The sliding bar is directly coupled to a piston and to a yoke with a slot that engages a sliding block. When a force is applied to the piston, the sliding block moves in the yoke slot, causing the yoke to rotate.

Q: What is the principle of scotch yoke mechanism?

A: The Scotch yoke (also known as slotted link mechanism) is a reciprocating motion mechanism, converting the linear motion of a slider into rotational motion, or vice versa. The piston or other reciprocating part is directly coupled to a sliding yoke with a slot that engages a pin on the rotating part.

Q: What is the formula for the scotch yoke mechanism?

A: The position of your yoke will be something like P=r * cos(theta) for a horizontal movement, where r is the radial distance from the crank center to the pin and theta is the angle of the crankshaft.

Q: What is the difference between a rack and pinion actuator and a scotch yoke actuator?

A: Scotch Yoke and Rack & Pinion actuators have been in widespread use for many years. Both are proven, reliable designs. Scotch Yoke actuators offer higher torque for the same frame size, while Rack & Pinon feature a constant torque throughout the cycle.

Q: What is the efficiency of the scotch yoke mechanism?

A: The scotch yoke mechanism converts its rotary motion obtained from the sprockets into reciprocating motion of the two plungers used to suck water in one stroke into the cylinder and to deliver the same out from it in the next stroke. Efficiency of the system is found up to 48%-and 2.7-liters discharge per minute.

Q: What is the difference between slider crank and scotch yoke mechanism?

A: Slider-Crank is limited by its slider length and may acquire large space and for continuous operation, the length to radius ratio of Slider: Crank must be at least 2:1. This will increase space requirement of the mechanism. Scotch-Yoke requires less space than Slider-Crank.

Q: What are the advantages of scotch yoke?

A: Advantages of Scotch Yoke Mechanism
Smoother operation due to fewer moving components. Engine efficiency is increased by a higher proportion of time spent at the top dead centre. It can be easily automated.

Q: What is the principle of scotch yoke actuator?

A: The scotch yoke principle is characterised by high torque at the beginning and end of each operation. This matches with the typical torque request of quarter-turn valves and increases safety, especially in applications where a valve remains stationary throughout long periods.

Q: What is the objective of scotch yoke mechanism?

A: A scotch yoke mechanism is used for activating the motion of the shaper frame during its strokes, that is forward and backward stroke is used for shaper and thus by performing the shaping operation at both sides.

Q: Is scotch yoke better than rack and pinion?

A: Rack & Pinion actuators are more compact and provide a constant torque output. They can be re-configured to either double acting or spring return designs. Scotch Yoke actuators are lower cost and feature a higher torque output for the same frame size.

Q: How does the yoke mechanism work?

A: Either sides of yoke is connected to each piston rods. pulley rotates, along with the small pulley the large pulley also rotates. This makes the scotch disk to rotate mean while the cam also reciprocates inside the yoke slot. This moves the yoke to and fro. This converts the rotary motion into reciprocating motion.

Q: Which link is fixed in the scotch yoke mechanism?

A: Scotch yoke mechanism.
The inversion is obtained by fixing either the link 1 or link 3, link 1 is fixed. In this mechanism, when the link 2 (which corresponds to crank) rotates about B as centre, the link 4 (which corresponds to a frame) reciprocates. The fixed link 1 guides the frame.

Q: Who invented the scotch yoke mechanism?

A: The Scotch Yoke Mechanism, "MYE", designed by EDIBON, is an example of slider-crank mechanism for converting the linear motion of a slider into rotational motion or vice versa. It is made of aluminum and consists of a rotary element, called crank, with a graduated disc.

Q: What is simple scotch yoke mechanism?

A: The Scotch Yoke Mechanism Explained
A Scotch Yoke mechanism is a unique type of motion converter. It consists of a pin (or crank), a yoke (a sliding block), and a guiding slot. As the pin moves in a circular path due to the rotation of a crank, it drives the yoke to move in a straight line.

Q: What is the degree of freedom of the scotch yoke mechanism?

A: It can be considered as single-degree-of-freedom translational and rotational motion.

Q: What is scotch yoke mechanism torque?

A: The Scotch Yoke Mechanism:
The lever is longer at the ends of stroke so that a given force results in more torque at the ends of travel than at the mid-travel positions. Additionally, the angular relationship between the input force and the lever also acts to increase the torque output.

Q: What is a scotch yoke actuator?

A: A scotch yoke actuator typically consists of a crank and piston system in a hollow cylinder. Pressure is applied to a side of the piston inside the cylinder. As a result, force is generated which moves the piston along the axis of the cylinder to rotate the actuator stem 90° with pilot air application.

Q: What are the advantages of scotch yoke mechanism?

A: The scotch yoke mechanism will generate perfect simple harmonic motion (sine wave), whereas the slider-crank mechanism will produce a slightly distorted sine wave. Because the output is simple harmonic motion, the scotch yoke mechanism is commonly used in testing equipment to simulate simple harmonic vibration.

Q: What are the parts of a scotch yoke?

Q: How many links are there in scotch yoke mechanism?

A: The double slider-crank linkage has four links joined in a kinematic chain and consists of two revolute joints and two sliding or prismatic joints. Different mechanisms obtained by fixing different links of a kinematics chain are known as its inversions.

As one of the leading scotch yoke actuator manufacturers and suppliers in China, we warmly welcome you to buy customized scotch yoke actuator at competitive price from our factory. Contact us for more details.

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