Telescoping Scotch Yoke Actuator for Compact Valve Actuation
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Solution Overview
Problem
Conventional Scotch yoke actuators require substantial installation space, are heavy, and have complex maintenance procedures due to their design, which leads to inefficiencies and reduced operational lifetimes, and reversing the rotational mode is time-consuming.
Innovation Solution
The design incorporates a telescoping assembly with a yoke having a passage that supports a pivotable slide member, allowing linear motion to be converted to torque with reduced footprint and improved stress distribution, and simplified assembly and maintenance methods by using interchangeable end caps and adjustable limit stop bushings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional Scotch yoke actuator design is used, then the actuator can convert linear motion to rotary motion, but the actuator requires substantial installation space and has large dimensions
Solution Approach 1:
The rod assembly is received within the yoke assembly, with the rod extending through a passage in the yoke. The slide member is received within the rod assembly and converts linear motion of the rod to rotary motion of the yoke. This nested configuration allows compact packaging of components, reducing the overall footprint and installation space required while maintaining the motion conversion capability.
2Weight of moving object
If a conventional Scotch yoke actuator design is used, then the actuator can provide rotational actuation, but the actuator is heavy
Solution Approach 1:
The actuator is divided into distinct functional assemblies: a yoke assembly that rotates, a rod assembly that moves linearly, and a slide member that couples them. This segmentation allows each component to be optimized independently for weight while maintaining the overall rotational actuation capability. The modular design reduces unnecessary material and simplifies the structure.
3Ease of repair
If a conventional Scotch yoke actuator design is used, then the actuator can operate reliably, but maintenance procedures are complex and time-consuming
Solution Approach 1:
The actuator is divided into modular assemblies (yoke assembly, rod assembly, slide member) that can be independently accessed and maintained. The rod assembly can be removed from the yoke assembly by disconnecting coupling mechanisms, allowing maintenance of individual components without disassembling the entire actuator, thus simplifying maintenance while maintaining reliability.
Solution Approach 2:
The rod assembly is designed to be extractable from the yoke assembly through the passage, allowing easy removal and replacement of wear components such as the slide member or rod itself. This extraction capability enables simple maintenance procedures while maintaining operational reliability through component replacement.
4Loss of time
If a conventional Scotch yoke actuator design is used, then the actuator can provide rotational motion, but reversing the rotational mode is time-consuming
Solution Approach 1:
The coupling between the rod assembly and yoke assembly is designed to be dynamically adjustable. The rod can be disconnected from the yoke and reconnected in an inverted configuration, allowing reversal of the rotational mode (clockwise to counter-clockwise or vice versa). This dynamic reconfigurability enables quick mode reversal without permanent fixed connections.
5Volume of moving object
If a compact design is used to reduce installation space, then the actuator footprint is reduced, but stress distribution may be compromised
Solution Approach 1:
The nested configuration of the rod assembly within the yoke assembly, with the slide member coupling them, allows compact packaging while maintaining proper stress distribution. The passage in the yoke provides a guided path for the rod, ensuring proper alignment and force transmission. The slide member distributes loads between the rod and yoke, preventing stress concentration despite the compact arrangement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces the overall size and weight of the actuator, improves stress distribution, and simplifies assembly and maintenance, allowing for efficient operation and easy reversal of rotational modes without disassembling the actuator from the valve.
Implementation Method 1
The rod assembly can be part of a piston assembly so that linear motion of a piston of the piston assembly can cause, via the rod assembly, a corresponding rotational motion of the yoke
Implementation Method 2
The first end cap can support a linear actuator relative to the housing. The linear actuator can move the first rod assembly in the first direction
Implementation Method 3
A Scotch yoke actuator can include a housing and a rod assembly that moves back and forth transverse to a rotatable shaft of a yoke that is offset from the rod assembly. The rod assembly can be part of a piston assembly so that linear motion of a piston of the piston assembly can cause, via the rod assembly, a corresponding rotational motion of the yoke
Implementation Method 4
The piston rod can be slidably supported with a sliding bushing
Implementation Method 5
The limit stop bushing can be threadedly adjustable relative to the housing to adjust a limit stop location for the first rod assembly relative to movement of the first rod assembly in the first direction
Data Source
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AI summary
Embodiments of the invention provide an actuator (100) for a valve assembly. The actuator can include a yoke (146) with at least one bore (196), a first rod assembly (136), and a first slide member (148) seated within the at least one bore and pivotally connected to the first rod assembly. The yoke can be configured to rotate about a yoke axis (198) to actuate the valve assembly. The first rod assembly can be configured to move in a first direction transverse to the at least one bore and the yoke axis. The first slide member can be configured to slide telescopically within the at least one bore as the first rod assembly moves in the first direction to transmit torque to the yoke for actuation of the valve assembly.