Threaded Insulating Rod Adjustment for Circuit Breaker Timing

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Solution Overview

Problem

Existing high voltage circuit breakers face challenges in achieving stable and reliable performance due to manufacturing and assembly tolerances, which affect the travel characteristics of arcing and contact separation, necessitating a secure and precise adjustment of the insulating rod length.

Innovation Solution

A system comprising a clutch and fitting with coordinated threads allows for adjustable length adjustment of the insulating rod, secured by a locking pin, eliminating the need for adhesives and tools, and ensuring precise alignment despite manufacturing tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the insulating rod length is fixed based on manufacturing tolerances, then the assembly process is simple, but the contact separation timing becomes inaccurate due to tolerance accumulation

Engineering Contradiction:
Improvecontact separation timingVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The insulating rod length is made dynamically adjustable through a clutch mechanism that can be rotated relative to the fitting. This allows the effective length to be changed during assembly to compensate for manufacturing tolerances, thereby achieving accurate contact separation timing without requiring extremely precise manufacturing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustment mechanism is segmented into distinct components: the clutch with external threads and the fitting with internal threads. This segmentation allows for independent optimization of each component and simplifies the adjustment process by providing a clear mechanical interface for length modification

Inventive Principle:
Principle #1Segmentation

2Reliability

If adhesives are used to secure the clutch position, then the adjustment is stable, but the assembly process becomes complex and costly

Engineering Contradiction:
Improveclutch position stabilityVSAvoidassembly process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The chemical bonding method (adhesives) is replaced with a purely mechanical locking system. The locking pin inserted through the securing opening in the clutch and engaging with the fitting provides stable positional fixation through mechanical interference, eliminating the need for adhesives and simplifying both the manufacturing and assembly processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The locking pin acts as an intermediary element that secures the clutch to the fitting without requiring adhesives. This simple mechanical intermediary provides reliable position stability while maintaining ease of manufacture and assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the clutch and fitting are made as separate adjustable components, then the length adjustment is precise, but the device complexity increases

Engineering Contradiction:
Improvelength adjustment precisionVSAvoidnumber of components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The clutch and fitting are designed as separate but closely integrated components with coordinated threading. This merging of concepts allows precise length adjustment through the thread engagement while maintaining a relatively simple overall structure. The clutch forms part of the lever mechanism and the fitting connects to the insulating rod, integrating the adjustment function into the existing structure without adding excessive complexity

Inventive Principle:
Principle #5Merging (Combining)

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 system provides a secure, reliable, and cost-effective method to adjust the insulating rod length, reducing the risk of mechanical failure and assembly errors, while ensuring correct contact separation timing and improved force distribution.

Implementation Method 1

The clutch includes a thread with a given thread pitch. The fitting also comprises a thread with a given thread pitch formed in coordination with the thread of the clutch. The fitting and the clutch are adjustably coupled with each other by means of their threads.

Methodology Applied
Scientific EffectThreaded fastening: Screw

Implementation Method 2

The system further comprises a securing member that is coupled with the clutch configured to counteract an unwanted rotation of the clutch relative to the fitting, wherein the fitting and the clutch each comprises a respective securing opening and wherein the securing member is formed as a locking pin which extends into the securing openings of the fitting and the clutch.

Methodology Applied
Scientific EffectMechanical locking: Pin

Data Source

PatentEP4381532B1A system and a method for adjusting a length of an insulating rod for a high voltage circuit breaker and a high voltage circuit breaker
Publication Date: 2025.09.03 HITACHI ENERGY LTD
  • EP4381532B1 patent drawingFigure 1
  • EP4381532B1 patent drawingFigure 2
  • EP4381532B1 patent drawingFigure 3

AI summary

A system and a method for adjusting a length of an insulating rod for a high voltage circuit breaker and a high voltage circuit breaker A system (10) for adjusting a length of an insulating rod (5) of a high voltage circuit breaker (1) comprises a clutch (11) and a fitting (12). The clutch (11) comprises a thread (18) with a given thread pitch, and the fitting (12) includes a thread (19) with a given thread pitch formed in coordination with the thread (18) of the clutch (11). The fitting (12) is adjustably coupled with the clutch (11) by means of the threads (18, 19) and the fitting (12) is configured to be fixedly coupled with the insulating rod (5) such that with respect to an assembled state of the system (10) with insulating rod (5) and with respect to a longitudinal axis (A) the length of the insulating rod (5) is adjustable due to rotation of the clutch (11) relative to the fitting (12).