Handle Arm Assembly Integrating Undervoltage Release Reset Mechanism
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Solution Overview
Problem
Existing undervoltage release mechanisms in circuit breakers require additional components for resetting, which can complicate the structure and functionality, and existing handle arm designs do not efficiently translate arcuate movement into actuation of the reset mechanism.
Innovation Solution
A handle arm assembly with a body and arm portion formed from a single piece of material, such as 1070 steel, that rotates through an arc to engage and actuate the reset mechanism, incorporating an interface lever for reliable retraction of the plunger when the handle is moved to the off position, allowing for overtravel compliance without applying undue force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate pin member is added to the handle arm to actuate the reset lever, then the reset function can be achieved, but the device complexity increases
Solution Approach 1:
The patent integrates the reset lever directly into the handle arm assembly, eliminating the need for a separate pin member. The handle arm itself is configured to directly engage and actuate the reset lever through its arcuate movement, merging two previously separate components into one integrated structure, thereby reducing device complexity while maintaining the reset function
Solution Approach 2:
The handle arm is designed to perform multiple functions: it operates the circuit breaker switches and simultaneously acts as the actuating mechanism for the reset lever. By making the handle arm multi-functional, the patent eliminates the need for dedicated separate components, reducing overall device complexity
2Ease of operation
If the handle arm rotates through a large arc to ensure proper engagement with the reset mechanism, then the ease of operation improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent introduces an interface lever as an intermediary component between the handle arm and the reset lever. This interface lever translates the arcuate movement of the handle arm into the linear motion required to actuate the reset lever, accommodating variations in handle arm rotation arc while ensuring reliable engagement, thereby reducing manufacturing precision requirements
Solution Approach 2:
The interface lever is designed with specific geometric parameters that allow it to accommodate a range of handle arm rotation arcs. By optimizing the lever arm lengths, pivot point positions, and engagement geometries, the system can tolerate manufacturing variations while maintaining proper function across the required rotation range
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
The solution provides a simplified and reliable mechanism for resetting the undervoltage release, accommodating overtravel and tolerance stackup, ensuring consistent operation of the circuit breaker without additional complex components.
Implementation Method 1
the magnetic force generated by the coil is sufficient to maintain a plunger in a retracted position
Implementation Method 2
when the voltage drops below the predetermined dropout level, a compression spring overcomes the magnetic force and extends the plunger out of the coil
Data Source
AI summary
A handle arm assembly is for a circuit interrupter including an undervoltage release mechanism having a reset mechanism. The handle arm assembly includes a body portion rotatable through an arc between an on position, an off position, and a reset position beyond the off position and an arm portion projecting laterally from the body portion out of the plane of the arc through which the body portion rotates. The body portion and the arm portion are formed from a single piece of material wherein the body portion and the arm portion are different portions of the single piece of material. The arm portion is structured to engage the reset mechanism in a manner such that arcuate movement of the arm portion as the body portion moves to the off position is translated into actuation of the reset mechanism.