Electric Actuator Selector Mechanism to Prevent Erroneous Power Cutoff
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Solution Overview
Problem
Existing electric actuators for valves require power cutoff through up-and-down motion of a clutch button or manual operation shaft, which can lead to erroneous switching and safety risks, particularly during manual operations.
Innovation Solution
An electric actuator design featuring a selector member with a detection object and position holding member, where the detection object moves between detectable and undetectable areas to control power supply, requiring both axial movement and rotation for switching, enhancing safety through a dual-engagement groove mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power cutoff is achieved by simple up-and-down motion of clutch button or manual operation shaft, then operation simplicity is improved, but safety deteriorates due to risk of erroneous switching
Solution Approach 1:
The patent transitions from one-dimensional up-and-down motion to two-dimensional operation requiring both axial movement and rotation. The selector member must be moved axially to disengage the position holding member from the first engagement groove, then rotated to move the detection object between detectable and undetectable areas, providing a more reliable switching mechanism that prevents erroneous operation.
Solution Approach 2:
The patent divides the power switching operation into two distinct phases: axial movement to disengage the position holding member from engagement grooves, and rotation to position the detection object relative to the detector. This segmentation ensures that both actions are intentionally performed, reducing the risk of accidental switching while maintaining operational clarity.
2Reliability
If dual-engagement groove mechanism with axial movement and rotation is implemented, then safety is improved by preventing erroneous operation, but device complexity increases
Solution Approach 1:
The selector member serves multiple functions: it acts as a manual operation input, a position indicator through its detection object, and a switching actuator through its dual movement (axial and rotational). The engagement grooves serve both as mechanical stops and as part of the switching mechanism, reducing the need for separate components and minimizing overall system complexity despite the enhanced safety features.
3Reliability
If detection object is positioned in detectable area when position holding member engages with first engagement groove, then power cutoff reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent designs the engagement grooves and detection object positioning such that when the position holding member engages with the first engagement groove, the detection object naturally aligns with the detectable area position. This equipotential design ensures that the safe state (power cutoff) is automatically achieved through the mechanical engagement itself, reducing the need for high-precision manufacturing while maintaining reliability.
Data Source
AI summary
An electric actuator includes a housing, an electric driving unit, an selector member being rotatable about a rotation axis and moving in a direction of the rotation axis, a position holding member and detection object provided in the selector member, a detector, an engagement groove provided on a cooperation surface inside the housing, and a biasing member biasing the selector member in the direction of the rotation axis to make the position holding member approach the cooperation surface. The engagement groove is formed so that the detection object is positioned in one of a detectable area and an undetectable area when the position holding member is engaged with the engagement groove, and the detector is configured to switch between supply and cutoff of power to the electric driving unit in accordance with whether or not the detection object is detected.