Circuit Breaker Control Unit Fastening for Breaking Shock Absorption

Solution Overview

Problem

Existing electrical circuit breakers face issues with HMI elements being fragile and prone to ejection or cracking due to breaking shocks during circuit operation, and traditional fastening methods exacerbate these issues.

Innovation Solution

A control unit design with a front sub-assembly secured by kinematic links allowing translation blocking and rotation freedom, using hooks and complementary members to distribute deformation and absorb shock without hard points, ensuring the sub-assembly bends but does not break.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the front sub-assembly is rigidly fixed to the rear sub-assembly using traditional fastening elements (screws), then the front sub-assembly is securely attached, but local stresses increase during triggering which risks cracking the front sub-assembly and damaging HMI elements

Engineering Contradiction:

Improveattachment strengthVSAvoidlocal stress concentration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The fastening members are designed to transition from a rigid fixed state during normal operation to a movable state during triggering. The front sub-assembly is allowed to move relative to the rear sub-assembly during breaking shocks, transforming the static rigid connection into a dynamic adaptive connection that absorbs shock energy and prevents stress concentration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The mechanical properties of the connection between front and rear sub-assemblies change based on operational conditions. During normal operation, the connection provides strong attachment; during triggering, the connection allows movement and deformation. This parameter change enables the system to adapt to different stress conditions and prevent cracking.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the front sub-assembly is made loose or removable to avoid stress concentration, then cracking is prevented, but the HMI elements become vulnerable to ejection during triggering

Engineering Contradiction:

Improvecracking preventionVSAvoidHMI element retention

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The connection between front and rear sub-assemblies is designed to be dynamic rather than static. During normal operation, the fastening members maintain a secure fixed connection that retains HMI elements. During triggering, the connection transitions to allow controlled movement and deformation, preventing cracking while maintaining HMI element retention through the distributed flexible attachment.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the front sub-assembly is rigidly fixed to prevent ejection of HMI elements, then retention is improved, but the breaking shock causes cracking and damage to HMI elements

Engineering Contradiction:

ImproveHMI element retentionVSAvoidshock damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The fastening members are designed to transition from a rigid fixed state during normal operation to a movable state during triggering. The front sub-assembly is allowed to move relative to the rear sub-assembly during breaking shocks, transforming the static rigid connection into a dynamic adaptive connection that absorbs shock energy and prevents stress concentration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The flexible connection design provides beforehand cushioning by allowing controlled deformation and movement during triggering. This pre-planned flexibility acts as a cushion that absorbs the breaking shock energy before it can reach and damage the HMI elements, while still maintaining sufficient retention.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Strength

If traditional screw fastening is used to secure the front sub-assembly, then attachment is strong, but hard points are created that increase local stresses during triggering

Engineering Contradiction:

Improveattachment strengthVSAvoidstress distribution

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The fastening members are designed to transition from a rigid fixed state during normal operation to a movable state during triggering. The front sub-assembly is allowed to move relative to the rear sub-assembly during breaking shocks, transforming the static rigid connection into a dynamic adaptive connection that absorbs shock energy and prevents stress concentration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention extracts the rigid constraint function from the fastening system, removing the hard points that cause stress concentration. By allowing movement and deformation during triggering, the system eliminates the problematic rigid constraints while maintaining attachment strength during normal operation.

Inventive Principle:

Principle #2Taking out (Extraction)

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 design effectively distributes and absorbs breaking shocks, preventing ejection and cracking of HMI elements while maintaining operational integrity.

Implementation Method 1

the complementary members include a first complementary member, which cooperates with the first fastening member so as to form a first kinematic link between the front sub-assembly and the rear sub-assembly, the first kinematic link being such that: the first edge is blocked in translation relative to the rear sub-assembly according to a first direction parallel to the height axis, and the first edge is free in rotation relative to the rear sub-assembly around a first axis parallel to the transverse axis

Methodology Applied

Scientific EffectKinematic link:

Implementation Method 2

Thanks to the invention, the front sub-assembly is held, along the two transverse edges, by kinematic links blocking translation but allowing rotation. In other words, the central portion is free to elastically deform by bending. During a triggering of the breaker unit, the deformations caused by the breaking shock are thus distributed and absorbed over the entire front sub-assembly. The absence of hard points means that the front sub-assembly bends but does not break.

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20250308826A1Control unit for an electrical circuit breaker and associated electrical circuit breaker

Publication Date: 2025.10.02 SCHNEIDER ELECTRIC IND SAS

AI summary

This control unit (20) comprises a casing (30) comprising a rear sub-assembly (34) and a front sub-assembly (100), which is assembled to the rear sub-assembly, and which comprises a central portion (102) with two opposing transverse edges (111, 112). The front sub-assembly (100) also comprises fastening members (121, 122) while the rear sub-assembly (34) comprises complementary members (131, 132), which are configured to cooperate with the fastening members to secure the front sub-assembly (100) to the rear sub-assembly (34), so that the two transverse edges are blocked in translation relative to the rear sub-assembly (34) according to two respective opposite and divergent directions, while each of the transverse edges is free to rotate relative to the rear sub-assembly (34) around an axis parallel to the considered transverse edge.