Actuator Lever Collet Coupling for Valve Shaft Precision
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Solution Overview
Problem
Existing process control valves with oversized shaft receptacles experience lost motion due to loose mechanical coupling, leading to inaccurate positioning and poor control over fluid flow, especially in throttling applications, and the removal of valve shafts from actuators is cumbersome and potentially damaging.
Innovation Solution
The use of actuator levers coupled with collets and collet tools that apply a controlled force to decouple and recouple the collet from the actuator lever, ensuring a tight mechanical coupling and facilitating easy removal and installation without damaging the valve assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an oversized shaft receptacle is used to ensure ISO standard compliance, then compatibility with various actuators is improved, but lost motion occurs due to loose mechanical coupling
Solution Approach 1:
A collet is introduced as an intermediary component between the shaft receptacle and the valve shaft. The collet fits tightly within the oversized shaft receptacle and engages the valve shaft, providing a precise mechanical coupling that eliminates lost motion while maintaining compatibility with ISO standard actuators.
Solution Approach 2:
The coupling system is divided into three separate components: the shaft receptacle (providing ISO standard interface), the collet (providing precise engagement), and the valve shaft. This segmentation allows each component to be optimized for its specific function while working together as a complete assembly.
2Manufacturing precision
If a collet is used to provide tight coupling between lever and valve shaft, then lost motion is reduced, but removal of the collet requires cumbersome and potentially damaging force
Solution Approach 1:
A removal tool is introduced to extract the collet from the lever. The removal tool engages with the collet and applies controlled force to back it out of the lever, eliminating the need for damaging hammering or blunt force while maintaining the tight coupling during operation.
3Manufacturing precision
If broaching technique is used to manufacture the shaft receptacle bore, then precise dimensional control is improved, but the process complexity and time increase
Solution Approach 1:
Instead of broaching the entire shaft receptacle bore to precise dimensions, the system segments the precision requirement to the collet component. The shaft receptacle can be manufactured with less complex processes, while the collet is precision-manufactured to provide the tight fit around the valve shaft.
Data Source
AI summary
Actuator levers, collets and collet tools for use in process control devices are disclosed. An example apparatus includes a tool for installing or removing a collet from an actuator lever. The example tool comprises a tool body and at least one of a plurality of inner-diameter threads, a plurality of outer-diameter threads, or a plate to removably couple the tool to at least one of an actuator lever or a collet. The tool is configured to apply a force to at least one of the actuator lever, the collet, a valve shaft, or an intervening structure to install the collet in or remove the collet from the actuator lever.