Arc Chamber Grid Assembly With Press-Fit Fixing Cap

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Solution Overview

Problem

The assembly process of arc chambers in circuit breakers is inefficient due to difficulties in consistent caulking, leading to potential deformation, displacement, and inconsistent gaps between grids, which affects productivity and maintenance.

Innovation Solution

An arc chamber design featuring grids with body and leg portions, and a fixing cap with protrusions and grooves for press-fitting, ensuring secure coupling and consistent spacing through frictional forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If caulking is used to couple the fixing plate to the grid, then the grid can be secured, but the assembly process becomes difficult to perform consistently and may cause deformation or cracking

Engineering Contradiction:
Improvecoupling securityVSAvoidassembly consistency
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the caulking process (mechanical deformation method) with a press-fit coupling system using protrusions and grooves. The protrusions on the fixing plate engage with corresponding grooves on the grid, providing secure coupling without deformation or cracking, thus eliminating the inconsistency issues associated with manual caulking.

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

Solution Approach 2:

The patent introduces protrusions and grooves as intermediary coupling elements between the fixing plate and the grid. These features act as a mediator that enables secure attachment through geometric interlocking, replacing the direct caulking process and ensuring consistent assembly quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple caulking operations are performed to ensure secure coupling, then the grid can be firmly attached, but the processing time increases and productivity decreases

Engineering Contradiction:
Improvecoupling securityVSAvoidassembly efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The coupling mechanism is segmented into discrete protrusion-groove pairs that provide immediate mechanical interlocking. This segmentation eliminates the need for multiple sequential caulking operations, as the geometric features provide inherent coupling security in a single assembly step, thereby improving productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent substitutes the time-consuming multiple caulking operations with a single press-fit action that engages the protrusions with grooves. This mechanical substitution dramatically reduces assembly time while maintaining or improving coupling security through the interlocking geometry.

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

3Strength

If strong force is applied during caulking to secure the grid, then the coupling can be firm, but the grid may be deformed, cracked, or twisted

Engineering Contradiction:
Improvecoupling forceVSAvoidgrid integrity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the high-force caulking process with a low-force press-fit operation. The protrusions and grooves are designed to engage through controlled insertion, providing firm coupling without applying excessive force that could deform, crack, or twist the grid, thus preserving manufacturing precision.

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

Solution Approach 2:

The patent changes the coupling mechanism from a force-intensive process to a geometry-intensive process. By designing specific protrusion and groove dimensions, the coupling strength is achieved through mechanical interlocking rather than applied force, preventing grid damage while maintaining coupling integrity.

Inventive Principle:
Principle #35Parameter changes

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

Facilitates easy assembly, reduces processing time, maintains consistent grid spacing, and allows for maintenance, thereby improving productivity and product quality.

Implementation Method 1

a plurality of fixing grooves coupled to the first protrusions is provided on an end of the coupling portion... ensuring secure coupling and consistent spacing through frictional forces

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3734635B1Arc chamber of circuit breaker
Publication Date: 2026.01.07 LS ELECTRIC CO LTD
  • EP3734635B1 patent drawingFigure 1
  • EP3734635B1 patent drawingFigure 2
  • EP3734635B1 patent drawingFigure 3

AI summary

The present device was conceived in order to resolve the aforementioned problem, and the objective thereof is to provide an arc chamber of a circuit breaker that enhances assemblability and ensures the consistency of the product. An arc chamber of the circuit breaker according to one embodiment of the present device comprises: a plurality of grids arranged at predetermined intervals outside a motion locus of a movable contactor and having a body portion and a leg portion extending from one side of the body portion; and a fixing cap having a receiving portion that is inserted into the leg portion in a press-fitting manner, wherein the fixing cap has a coupling portion extending to a side of the body portion at one side thereof.